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| Monday Digital Poster | Tuesday Digital Poster | Thursday Digital Poster |
| 3339 | Computer 1
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Improved MUSSELS Reconstruction for High Resolution Diffusion Weighted Imaging Using Fast Iterative Re-weighted Least Squares Algorithm |
1University of Iowa, Iowa City, IA, United States |
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Multi-shot diffusion-weighted imaging reconstructions are challenged by the inter-shot phase inconsistency that exists between the data from different shots. The MUSSELS algorithm enabled the direct reconstruction of the multi-shot k-space data by posing it as a low-rank based matrix recovery problem. The iterative algorithm has been shown to successfully recover the missing k-space samples in accelerated and non-accelerated acquisitions. However, the reconstruction time increases as the number of shots\acceleration increases. We propose a new formulation based on iterative re-weighted least squares that increase the computational efficiency of the matrix completion by several folds to speed up the recovery of multi-shot data. |
| 3340 | Computer 2
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Simultaneous Multi-Slice Diffusion MR Reconstruction using Coil-Combined Split Slice-GRAPPA |
1ECE, University of Utah, SALT LAKE CITY, UT, United States, 2Radiology and Imaging Science, University of Utah, SALT LAKE CITY, UT, United States, 3Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States |
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Simultaneous multi-slice (SMS) acquisition accelerates diffusion MR imaging by acquiring multiple slices simultaneously. In this work, we propose a new method, termed coil-combined split slice-GRAPPA (CC-SSG), to improve the quality of SMS diffusion imaging reconstruction. By optimizing split-slice-GRAPPA (SSG) kernels specifically for coil combining, our approach allows for a better trade-off for suppressing inter-slice and intra-slice leakages and minimizes the mean-square-error (MSE) of coil-combined images. The proposed CC-SSG method improves the estimation of diffusion tensor imaging (DTI) parameters over existing methods. |
| 3341 | Computer 3
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Joint-diffusion GRAPPA: enabling higher acceleration rates in dMRI by exploiting joint information from the k- and q-space |
1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Laboratorio de Procesado de Imagen, Universidad de Valladolid, Valladolid, Spain, 3Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States |
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In this work, we generalize conventional GRAPPA-based dMRI reconstruction by exploiting joint information from the Our novel method, joint-diffusion GRAPPA, is validated with in-vivo multi-slice dMRI data, where we show it always outperforms conventional GRAPPA in terms of image |
| 3342 | Computer 4
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Use of self-navigation to enable efficient 3D DWI SE-EPI multislab multiband imaging |
1University of Minnesota, Minneapolis, MN, United States, 2Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States |
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A method is proposed for self-navigation of DWI 3D multislab multiband SE-EPI, to enable whole brain high-resolution imaging, with optimal imaging TR for higher SNR efficiency. Data for high b-value (b=3k s/mm2) and 1mm3 resolution is presented. |
| 3343 | Computer 5
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Acceleration of 3D diffusion MRI using a kernel low rank compressed method |
1Electrical Engineering, University at Buffalo, State University of New York, buffalo, NY, United States, 2Radiology, New York University School of Medicine, New York City, NY, United States, 3Radiology & Electrical Engineering, Stanford University, Stanford, CA, United States, 4Paul C Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Shenzhen, China, 5Biomedical Engineering, University at Buffalo,State University of New York, buffalo, NY, United States |
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Diffusion MRI has showed great potential in probing tissue microstructure and brain structural connectivity. However, high-resolution diffusion MRI with multiple direction is limited by the lengthy scan time. In this abstract, we apply a kernel low rank model to accelerate diffusion imaging by undersampling the k-space. This method is validated using high-resolution mouse brain datasets. Compared with the conventional compressed sensing method, the proposed method demonstrate more accurate mean diffusivity, fractional anisotropy and fiber orientation distribution estimates with acceleration factors up to 8. |
| 3344 | Computer 6
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Deep Learned Diffusion Tensor Imaging |
1Department of Biomedical Engineering, Department of Electrical Engineering, The State University of New York at Buffalo, Buffalo, NY, United States, 2Radiology, New York University School of Medicine, New York City, NY, United States, 3Paul C. Lauterbur Research Center for Biomedical Imaging, Medical AI research center, SIAT, CAS, Shenzhen, China, 4Department of Computer Science, Virginia Tech, Blacksburg, VA, United States |
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Diffusion tensor imaging typically requires acquisition of a large number of diffusion weighted images (DWI) for accurate fitting of the tensor model due to the issue of low SNR. This abstract presents a deep learning method to generate FA color map showing the primary diffusion directions from very few DWIs. The method uses deep convolutional neural networks to learn the nonlinear relationship between the DWIs and the FA color maps, bypassing the conventional DTI models. Experimental results show that the proposed method is able to generate FA color maps from only 6 DWIs with quality comparable to results from 270 DWIs using conventional tensor fitting. |
| 3345 | Computer 7
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Self-navigated Half-Fourier Multi-shot Echo-planar DWI Reconstructions for Brain Imaging |
1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands |
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EPI trajectories using Half-Fourier achieve shorter echo times and therefore higher SNR, which is especially desirable in low-SNR applications like diffusion-weighted MRI. For the same reason, methods enabling phase-corrected image recovery for multi-shot diffusion acquisitions have been intensively studied for both spiral and EPI trajectories. In this work, two algorithms are presented comprising both half-Fourier and the multi-shot same-magnitude constraints to exploit the advantages of both techniques. The algorithms are shown to robustly recover interleaved half-Fourier datasets from in-vivo brain acquisitions. |
| 3346 | Computer 8
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Multi-shot Diffusion EPI Reconstruction with Iterative Rigid Motion-correction and Motion-induced Phase-correction for Brain Imaging |
1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands |
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Multi-shot diffusion-weighted imaging offers increased SNR and higher resolution, but makes the acquisition vulnerable to shot-specific phase variations and macroscopic inter-shot motion. A wide range of iterative phase-corrected reconstruction schemes have been proposed to overcome the inter-shot phase inconsistencies, but robust motion estimation is still challenging due to the inherently low SNR of DWI. This work moves forward from initial one-time rigid motion estimation to an alternating optimization balancing the joint image, phase and motion estimation. A novel multi-shot echo-planar diffusion algorithm with iterative motion and phase correction is presented in simulations and in-vivo. |
| 3347 | Computer 9
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Accelerating Iterative SENSE-based Algorithms for Cartesian Trajectories using the Point Spread Function and Coil Compression |
1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands |
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For multi-shot diffusion-weighted imaging, iterative SENSE-based algorithms like POCSMUSE are boosting SNR allowing for higher image resolution. These advantages are achieved at the cost of higher computational load, thereby narrowing the clinical use case. The Cartesian implementation of such SENSE algorithms iteratively involves time-consuming 1D-Fast Fourier Transforms. In this abstract, the well-known point spread function for regular Cartesian undersampling is exploited to accelerate gradient- and projection-based SENSE updates. Accelerations of approximately 45% were achieved. Furthermore, coil compression is evaluated for these algorithms. |
| 3348 | Computer 10
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Super-Resolution Diffusion Imaging using Deep Learning: A Feasibility Study |
1Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indiana University, Indianapolis, IN, United States, 2Indiana Alzheimer Disease Center, Indianapolis, IN, United States |
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In this study, we present and validate the efficacy of using a state-of-the-art deep-learning method to achieve submillimeter high-resolution diffusion-weighted (DW) images. The 2D-based deep-learning method was validated by comparing diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) of the deep-learning high-resolution images and the ground-truth. |
| 3349 | Computer 11
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Super-Resolution Hybrid Diffusion Imaging (SR-HYDI) |
1Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indiana University, Indianapolis, IN, United States, 2Indiana Alzheimer Disease Center, Indianapolis, IN, United States, 3University of Bordeaux, LaBRI, UMR 5800, PICTURA, F-33400 Talence, France, 4CNRS, LaBRI, UMR 5800, PICTURA, F-33400 Talence, France |
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In this study, we present and validate an efficient pipeline for submillimeter super-resolution hybrid diffusion imaging (SR-HYDI). The pipeline employs a collaborative patch-based super-resolution interpolation approach, which uses self-similarity to drive the reconstruction of diffusion-weighted images. The FA and MD generated from the proposed pipeline are compared against the ground-truth for validation. |
| 3350 | Computer 12
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Complex-valued diffusion MRI data processing: Application to neural soma imaging |
1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom, 3Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 4Department of Radiology, New York University School of Medicine, New York, NY, United States, 5School of Psychology, Australian Catholic University, Melbourne, Australia |
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Microscopic diffusion anisotropy imaging requires averaging the diffusion signal over the gradient directions to regress out the unwanted effects of the fibre orientation distribution. However, Rician noise biases the mean signal calculations especially in the high b-value regime and subsequently the estimation of microstructural tissue features. In this work we develop new data processing methods using complex-valued MRI data that remove the background phase and hence retain the Gaussian characteristics of the signal noise, which is demonstrated in neural soma imaging, a novel application of the Spherical Mean Technique (SMT). |
| 3351 | Computer 13
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Giving up the ghost: a systematic comparison of 2D phase correction algorithms in multi-shell high angular diffusion weighted imaging |
1Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 3Philips Healthcare UK, Guildford, Surrey, United Kingdom, 4Developmental Imaging and Biophysics Section, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 5Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 6Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy |
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The echo planar imaging (EPI) Nyquist ghost often requires complex 2D phase error corrections in order to be robustly removed. Several methods exist but have not yet been systematically evaluated in high b-value diffusion-weighted (DW) EPI, where lower signal-to-noise ratios may affect the phase error estimation. We explore here the influence of different 2D phase-error corrected reconstruction methods on quantitative parameters derived from DW-EPI, and demonstrate that errors in parameter estimations relating to the Nyquist ghost can persist even after 2D phase-error correction. |
| 3352 | Computer 14
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Whole-brain DTI at 860 μm isotropic resolution in 10 minutes on a commercial 3T Scanner |
1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, United States, 2Martinos Center for Biomedical Imaging, Charlestown, MA, United States |
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We describe an acquisition and reconstruction methodology that enables in vivo human diffusion tensor imaging with whole-brain coverage and 860$$$\mu$$$m isotropic spatial resolution, all within a 10 minute acquisition window on a commercial 3T scanner. Our approach is enabled by combining the gSlider-SMS acquisition approach (which uses simultaneous multi-slab acquisition for increased spatial coverage, combined with highly-efficient RF slab-encoding to achieve high spatial resolution) with an SNR-enhancing joint reconstruction approach that mitigates the noise associated with high-resolution acquisition. |
| 3353 | Computer 15
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Estimation and Correction of Image Phase in diffusion weighted MRI using Deep Learning |
1Computer Science, Technical University Munich, Munich, Germany, 2GE Healthcare, Munich, Germany, 3Physics, Technical University Munich, Munich, Germany, 4MR Applied Science Laboratory Europe, GE Healthcare, Stockholm, Sweden |
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The phase of diffusion weighted MR images (DWI) is regularly discarded in clinical application although it might contain valuable information, as it is composed of phase contributions due to rigid motion, eddy currents and brain pulsation among others. In this work we take advantage of a neural network to separate the different phase components in individual DWI phase images. This enables estimating the amount of brain pulsation from DWI and modelling brain pulsation. The gained information may be used for phase correction, which eventually will allow using real-valued DWI (instead of magnitude DWI) to eliminate the Rician bias. |
| 3354 | Computer 16
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Nyquist Ghost Correction of High-Resolution SMS Breast DWI with Ghost/Object Minimization |
1Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 3Radiology, University of Minnesota, Minneapolis, MN, United States |
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A recent novel approach to acquire high-resolution breast DWI uses a simultaneous multi-slice (SMS) SE-EPI sagittal acquisition. In EPI, Nyquist ghosts are typically corrected using a 3-line navigator, which often fails in SMS SE-EPI breast DWI due to low SNR, insufficient fat suppression, and larger B0 inhomogeneity. In this work we compare a referenceless ghost correction method, called Ghost/Object minimization, with the standard 3-line navigator in high-resolution breast DWI. Ghost/Object provides more reliable 1st-order ghost correction in a dynamic and slice-specific way, which improves image quality and reduces bias in ADC values compared to the standard correction. |
| 3355 | Computer 17
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Pseudo-3D Diffusion-Weighted Imaging of the Brain using Echo Planar Imaging with Compressed SENSE (EPICS) |
1Radiology, Kumamoto University, Kumamoto-shi, Japan, 2Philips Japan, Tokyo, Japan, 3Diagnostic Radiology, Kumamoto University, Kumamoto-shi, Japan |
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We attempted to obtain brain high-resolution pseudo-3D (2D multi-slice acquisition with very thin slice thickness) diffusion-weighted echo planar imaging (DW-EPI) using a hybrid compressed sensing and sensitivity encoding (Compressed SENSE) framework (EPICS). pseudo-3D-DWI with EPICS achieved high-resolution (1.15 mm3) isotropic DWI within clinically feasible scan time. Furthermore, EPICS clearly improved the accuracy and robustness of ADC values in high b-value brain DWI with pseudo-3D acquisition without any penalty for scan parameters. |
| 3356 | Computer 18
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Fast reconstruction of fractional anisotropy with two-dimensional principal component analysis based recognition |
1The Key Laboratory for Interdisciplinary Research, Institute of Biophysics, China Academy of Sciences, Beijing, China, 2State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 3The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China, 4University of Chinese Academy of Sciences, Beijing, China, 5Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 6Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 7UCSF/UC Berkeley Joint Graduate Group in Bioengineering San Francisco, San Francisco, CA, United States |
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Reducing the acquisition time for obtaining fractional anisotropy (FA) is of paramount importance to investigate cerebral microstructures and morphologies non-invasively. This is the first time to introduce the two-dimensional principal component analysis recognition reconstruction (i.e. 2D-PCA-RR) in recovering highly under-sampled FA maps with 5-fold acceleration of data acquisition. An in-house data processing procedure is implemented to optimize signal-to-noise ratio and construct a distortion-free database. Our results from two different under-sampling patterns show a superior performance gain from the 2D-PCA-RR algorithm as compared to conventional reconstruction methods. |
| 3357 | Computer 19
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Acquisition and processing strategy for obtaining high quality, distortion free diffusion MRI of the brainstem and cervical spine |
1Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, United States, 2NIH MRI Research Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, United States, 3Laboratory of Brain and Cognition, National Institute of Mental Health, NIH, Bethesda, MD, United States, 4Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, United States, 5Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States, 6NIH, Bethesda, MD, United States, 7Boston Children's Hospital and Harvard Medical School, Boston, MA, United States, 8Icahn School of Medicine at Mount Sinai, New York City, NY, United States |
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Despite its clear clinical and research usefulness, high quality in-vivo diffusion MRI imaging of the brainstem and the cervical spine has been challenging due to susceptibility-induced distortions and ghosting in echo planar images (EPI). In this study, we propose an acquisition and data processing strategy that can be carried out on clinical scanners with commonly available EPI sequences with good resolution and in a reasonable scan time (less than 30 minutes). We apply this acquisition strategy to the study of pyramidal decussation in subjects with Moebius syndrome and mirror movements. |
| 3358 | Computer 20
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Accelerating Diffusion MRI via Slice Undersampling and Deep-Learning Reconstruction |
1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States |
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In this abstract, we present a proof-of-concept method for effective diffusion MRI reconstruction from slice-undersampled data. Instead of acquiring full diffusion-weighted (DW) image volumes, only a subsample of equally-spaced slices are acquired. We show that the complementary information from DW volumes corresponding to different diffusion wavevectors can be harnessed using graph convolutional neural networks for reconstruction of the full DW volumes. |
| 3359 | Computer 21
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Deep learning for DSI parameter map generation without image pre-processing |
1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Bioengineering, University of Utah, Salt Lake City, UT, United States |
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Recent advances in diffusion spectrum imaging (DSI) have reduced scan time considerably. Through the use of deep learning, DSI parameter maps (NODDI, GFA, etc.) can be generated with only a fraction of the number of q-space samples compared to conventional acquisition strategies. However, image pre-processing prior to the deep learning parameter map generation step is a computational bottleneck. This abstract explores if this bottleneck can be bypassed entirely and use images straight from the scanner as CNN inputs. We show that the image pre-processing is not necessary to generate NODDI and GFA parameter maps--thereby avoiding the image processing computation time. |
| 3360 | Computer 22
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Phase-Error-Free Multi-shot 3D DWI using Filtered Back Projection Reconstruction |
1AllTech Medical Systems, Chengdu, China, 2Alltech Medical System America, Solon, OH, United States |
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Conventional multi-shot DWI is known to suffer from inter-shot phase inconsistencies due to motion and hardware imperfections. In this work, we present a new approach for phase-error-free diffusion imaging by using multi-shot Paddlewheel-shaped EPI acquisition and filtered back projection (FBP) Reconstruction. The necessity of inter-shot phase correction is removed due to the magnitude-only nature of FBP. Reduced FOV excitation scheme is incorporated to reduce scan time and artifacts. Exemplary results of head and prostate DWI are demonstrated to show the efficacy of the proposed methods. |
| 3361 | Computer 23
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Imaging Cortical Columns in Gray Matter with Sub-Millimeter isotropic DTI |
1Duke University Medical Center, Durham, NC, United States |
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The microarchitecture in gray matter of the human brain is comprised of short (<3 mm) cortical columns that traverse six cortical layers. To most accurately delineate these columns in-vivo, it is essential to achieve isotropic spatial resolutions on the order of 0.8 mm or less. In this study, we present a means of acquiring diffusion tensor imaging data with ultrahigh spatial resolution to effectively characterize the complex architecture of gray matter. |
| 3362 | Computer 24
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High-resolution DWI for breast by using multi-band sense technique |
1Radiology Department, Peking Union Medical College Hospital, Beijing, China, 2Philips Healthcare, Beijing, China |
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Two challenges in clinical MRI are the slow image acquisition time and low image resolution compared to other clinical imaging technique such as CT. The purpose of this study is to improve the image quality of diffusion weighted imaging (DWI) for clinical breast examination within a limited scanning time by using multi-band sense technique. |
| 3363 | Computer 25
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Rapid and Accurate NODDI Parameter Estimation with the Spherical Mean Technique |
1Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, Los Angeles, CA, United States |
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Neurite orientation dispersion and density imaging (NODDI) is a widely used tool for modeling microstructure using diffusion MRI, but its computational cost can be prohibitively expensive. This work investigates the efficacy of integrating the spherical mean technique (SMT) into a non-linear optimization framework to improve NODDI parameter estimation. Through quantitative simulation, comparative, and reliability analyses, we found that integrating SMT into more traditional non-linear optimization enables rapid, accurate, and reliable estimation of neurite density and dispersion compared to other approaches. |
| 3364 | Computer 26
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Assessment of the reproducibility of structural brain networks derived using different edge-weighting strategies |
1Medicine, Cardiff University, Cardiff, United Kingdom, 2Psychology, Cardiff University, Cardiff, United Kingdom, 3Psychology, Australian Catholic University, Melbourne, Australia |
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Structural brain networks derived from diffusion Magnetic Resonance Imaging data can use various tract metrics to weigh the network edges. In this work we use the Human Connectome Project test-retest diffusion MRI data to assess the reproducibility of structural brain networks, their edges and their graph-theoretical measures derived using different edge-weighting strategies. |
| 3365 | Computer 27
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White matter parcellation test-retest reproducibility of diffusion MRI tractography fiber clustering |
1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States |
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Fiber clustering is a popular strategy for automated white matter parcellation using diffusion MRI tractography. However, there has been no investigation to assess fiber clustering parcellation test-retest reproducibility, i.e. whether white matter parcellations could be reliably reproduced in repeated scans. This work presents the first study of fiber clustering white matter parcellation test-retest reproducibility. We perform evaluation on a large test-retest dataset, including a total of 255 subjects from multiple independently acquired datasets. Our results in general indicate that the fiber clustering method produced more reproducible white matter parcellations than a popular cortical-parcellation-based method. |
| 3366 | Computer 28
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Connectome analysis of world class gymnasts using probabilistic multi-shell multi-tissue constrained spherical deconvolution tracking |
1Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan, 2Department of Radiological Sciences, Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo, Japan, 3Department of Sports Science, Juntendo University Graduate School of Medicine, Tokyo, Japan, 4Department of Radiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan |
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We analyzed the brain anatomical networks between world-class gymnasts and controls using probabilistic Multi-shell, Multi-tissue Constrained Spherical Deconvolution tracking method. Our results showed higher neural connectivities in gymnasts in the brain areas related to motor activity and visual perception. In addition, a positive correlation between difficulty-score (D-score) and brain connectivity was also in the brain areas including auditory, limbic, associative and visual area. In conclusion, our findings can be useful for a better understanding of neural changes related to gymnastic skills. |
| 3367 | Computer 29
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A novel connectomics metric for investigating the structural-functional relationship in the brain |
1School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia, 2Brain and Mind Centre, The University of Sydney, Sydney, Australia, 3Sydney Imaging, The University of Sydney, Sydney, Australia, 4Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia |
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We present a novel connectomics metric that quantifies the relationship between structural connectivity (SC) and functional connectivity (FC) in each connection in the brain. The metric is based on a biologically meaningful and quantitative measure of SC, followed by normalization of both modalities to a common scale. We demonstrated the utility of the metric in examining structural-functional relationships in pairs of homologous connections, detecting homologues that are dissimilar. The metric is more informative than using FC in isolation, and might provide insights into factors that contribute to FC beyond the strength of SC (e.g., indirect connections, organization of fibres). |
| 3368 | Computer 30
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Bundle Analytics: a computational and statistical analyses framework for tractometric studies |
1Intelligent Systems Engineering, Indiana University Bloomington, Bloomington, IN, United States, 2School of Public Health, Indiana University Bloomington, Bloomington, IN, United States, 3Pervasive Technology Institute, Indiana University Bloomington, Bloomington, IN, United States |
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Bundle Analytics promises fast, robust, and flexible computational and statistical analyses for tractometric studies on clinical data. It uses information from both tractometry, and anatomy to analyze the extracted fiber bundles from challenging clinical datasets. It uses streamline-based efficient algorithms to register and extract fiber bundles from a tractogram, and applies linear mixed models in the extracted bundles to find significant differences at specific locations of the bundles across groups. Finally, the method does not require training, an important advantage over deep learning methods. |
| 3369 | Computer 31
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Is it feasible to directly access the bundle’s specific myelin content, instead of averaging? A study with Microstructure Informed Tractography |
1Department of Computer Science, University of Verona, Verona, Italy, 2Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 3Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland, 4FIDMAG Germanes Hospitalàries Research Foundation, Sant Boi de Llobregat, Barcelona, Spain |
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Diffusion MRI connectometry is a widely used tool to investigate features of structural connectomes that reflect differences in white matter tracks integrity. It consists in averaging microstructural tissues properties (obtained from any voxel-wise map) along streamlines recovered with diffusion tractography. Nevertheless, the average of a microstructural measure is a weak information about an entire bundle. Using microstructure-informed tractography (COMMIT), we were able to simultaneously estimate fiber’s specific myelin water fraction, intra-axonal volume fraction, and g-ratio. We also computed new connectomes with bundles’ specific measures instead of the commonly used averages. |
| 3370 | Computer 32
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Using HCP data to improve diffusion tractography in routine-quality data: Application to the virtual dissection of the SLF system |
1Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital and Harvard Medical School, SOMERVILLE, MA, United States |
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The development of scanners with ultra-high gradients, spearheaded by the Human Connectome Project, has led to dramatic improvements in the spatial, angular, and diffusion resolution that is feasible for in vivo diffusion MRI acquisitions. Here we show that global probabilistic tractography with anatomical priors can be trained on such data, which can only be acquired on a handful of Connectome scanners worldwide, and improve the accuracy of tractography in more widely available, routine-quality diffusion data. We apply this method to reconstruct the three subcomponents of the SLF and show its superior accuracy compared to a conventional multi-ROI approach. |
| 3371 | Computer 33
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Reducing false-positive connections using hierarchical microstructure-informed tractography |
1Computer Science Department, University of Verona, Verona, Italy, 2Athena Project-Team, Inria Sophia-Antipolis Méditerranée, Université Côte d'Azur, Nice, France, 3Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Radiology Department, University Hospital Center (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 5Sherbrooke Connectivity Imaging Laboratory (SCIL), University of Sherbrooke, Sherbrooke, QC, Canada, 6Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Science, Sherbrooke Molecular Imaging Center, Sherbrooke, QC, Canada |
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Tractography has proven particularly effective for studying non-invasively the neuronal architecture of the brain, but recent studies have showed that the high incidence of false-positives can significantly bias any connectivity analysis. Last year we presented a method that extended COMMIT framework to consider the prior knowledge that white matter fibers are organized in bundles. Inspired by this, here we propose another extension to further improve the quality of the tractography reconstructions. We introduce a novel regularization term based on the multilevel hierarchy organization of the human brain and we test the results on both synthetic phantom and in vivo data. |
| 3372 | Computer 34
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TractEM: A fast protocol for Whole Brain Tractography |
1Computer Science, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institue of Imaging Science, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 4Electrical Engineering, Vanderbilt University, Nashville, TN, United States, 5Laboratory of Behavioral Neuroscience, National Institue of Aging, National Institutes of Health, Baltimore, MD, United States, 6Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States |
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We introduce TractEM, a tractography-based whole-brain labeling protocol informed by the Eve Labeling [1] procedures from the single-subject Johns Hopkins white matter atlas [1, 2]. This project proposes to create a resource of manually labelled white matter atlases that is driven by state-of-the-art diffusion tractography, and can be manually created in less than 6 hours. We defined and tested the TractEM protocol on 61 tracts for 20 subjects, with multiple raters per subject, and show moderate to high reproducibility for most labels. TractEM should be a useful resource for generating target templates for automated labeling methods. |
| 3373 | Computer 35
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Structural anatomy of the executive control network – a high angular resolution diffusion MRI study |
1Australian eHealth Research Centre, CSIRO, Brisbane, Australia, 2Department of Biomedical Sciences, Macquarie University, Sydney, Australia, 3Sydney Translational Imaging Laboratory, Heart Research Institute, University of Sydney, Sydney, Australia, 4Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia |
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In this abstract, our aim is to investigate the relationship between executive function and the underlying structures of the executive control network (ECN) in the normal population. To this end, we acquired multi-shell diffusion MRI data with 391 gradient directions to estimate the structural connectivity within this functionally-defined network, and evaluated the executive function of the subjects. We used network-based statistic (NBS) to assess the relationships between executive function and the ECN connectivity, and found that the structural connectivity between hemispheres displayed positive correlation with higher executive function performance, while the connectivity within a sub-network in the right hemisphere showed a negative correlation with executive function. |
| 3374 | Computer 36
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In vivo Diffusion MRI ODF-Fingerprinting performance relative to an HCP reference |
1Center for Advanced Imaging Innovation and Research (CAI2R), NYU School of Medicine, New York, NY, United States, 2Center for Biomedical Imaging, Dept of Radiology, NYU School of Medicine, New York, NY, United States, 3The Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY, United States, 4Department of Neurosurgery, Perlmutter Cancer Center, Neuroscience Institute, Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY, United States |
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High quality diffusion acquisitions are routinely used to study white matter architecture and brain connectivity in vivo. A key step for successful tractography of neuronal tracts is correct identification of the tract directions in each voxel. The recently proposed ODF-Fingerprinting method has been demonstrated in computer simulations and qualitative in vivo results to improve detection of fiber pairs with small crossing angles whilst maintaining fiber direction precision. Here we evaluate the performance of ODF-Fingerprinting and several other fiber direction identification algorithms quantitatively in vivo in a downsampled DWI dataset where the high resolution dataset provides a reference standard. |
| 3375 | Computer 37
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Towards a deep learning model for diffusion-aware tractogram filtering |
1KTH Royal Institute of Technology, Stockholm, Sweden, 2Université de Sherbrooke, Sherbrooke, QC, Canada |
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We propose a deep learning model that is able to separate a tractogram into sets of anatomically plausible and implausible streamlines. In contrast to existing methods, our model relies solely on the measured diffusion signal as an input ensuring independence of potential misalignments between subjects. The model is shown to generalize to different tractography methods and has the potential to simultaneously learn from multiple supervisor methods. |
| 3376 | Computer 38
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Tractostorm: Evaluation of intra and inter rater reproducibility in tractography dissection |
1Computer Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada, 2IMN UMR 5293, Université de Bordeaux, Bordeaux, France |
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Investigative studies of white matter structures using tractography often require manual virtual bundle dissection to be performed. Human errors and personal decisions make these manual segmentations hard to reproduce. Reproducibility assessment of raters is common practice in other neuroimaging field where segmentation protocols were refined to maximize reproducibility. However, this has not been done in the field of diffusion tractography. The contribution of this study is to provide the first large-scale, multi-center variability assessment of virtual dissection of tractography dataset. |
| 3377 | Computer 39
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Brain tumors: a challenge for tracking algorithms |
1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada, 2Division of Neurosurgery and Neuro-Oncology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, QC, Canada, 3Imeka Solutions Inc, Sherbrooke, QC, Canada |
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In tumor cases, several fiber bundles are displaced, destroyed, or infiltrate the tumor zone. For surgical planning, it is important to have the best estimation of the bundles near the tumor and in the edema. In neurosurgical tractography, DTI is the clinical standard and most used tractography method in publications. DTI does not correctly estimate local crossing fibers and is limited by edema contamination. In this work, we compare 4 tracking algorithms (DTI, HARDI deterministic, probabilistic, a new probabilistic edema-informed) applied to tumor cases, show differences and advise on the choice of tractography algorithm to be used in neurosurgical cases. |
| 3378 | Computer 40
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Optimized DTI acquisition and tractography pipeline for a reliable reconstruction of the facial nerve in patients with vestibular schwannoma |
1Padova Neuroscience Center, University of Padova, Padova, Italy, 2Department of Information Engineering, University of Padova, Padova, Italy, 3Department of Neurosciences, University of Padova, Padova, Italy, 4Department of Developmental Psychology and Socialisation, University of Padova, Padova, Italy, 5Neuroradiology Unit, University of Padova, Padova, Italy |
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Vestibular schwannomas (VS) are intracranial tumors that can cause the dislocation of the facial nerve (FN). The location of the FN is therefore a priori unknown to the surgeon and this is the main reason why patients with VS may experience FN damage during the surgery, leading to facial paralysis. In this work we used a multi-shell DTI acquisition to perform probabilistic fiber tracking for the preoperative determination of FN course in patients with VS. High-resolution anatomical scans were used to help the fiber tracking algorithm to obtain a reliable reconstruction also when the FN course had a complex configuration. |
| 3379 | Computer 41
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Comparison of diffusion MRI data with different b-values in trigeminal nerve tracking with unscented Kalman filter tractography |
1Nuclear Industry 215 Hospital of Shaanxi Province, Xianyang, China, 2Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 3Cantonal Hospital St. Gallen, St. Gallen, Switzerland |
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Diffusion MRI enables improved identification of the trigeminal nerve by tracking of its 3-D trajectory. To explore optimal methods for trigeminal nerve tracking using diffusion MRI, we compared tracking results from acquisitions with different b-values using single- and multi-fiber tractography methods. We found that the trigeminal nerve can be best tracked using b=3000 data with a two-tensor fiber model. We suggest that these settings can potentially be suitable for clinical applications, e.g., diagnosis and evaluation of trigeminal neuralgia. |
| 3380 | Computer 42
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Toward identifying individual branches of the trigeminal nerve with dMRI-based tractography at 7 Tesla: methodological considerations |
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 3Department of Diagnostic & Biological Sciences, University of Minnesota, Minneapolis, MN, United States, 4Department of Neurology, University of Minnesota, Minneapolis, MN, United States, 5Department of Radiology, University of Minnesota, Minneapolis, MN, United States |
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Trigeminal Neuralgia is a debilitating neuropathic condition affecting the trigeminal nerve. Tractography allows for the possibility of identifying the three branches of the nerve to assist in refining the etiopathology of trigeminal neuralgia. In this study we identify methodological factors that contribute to reliability in identifying the branches of the nerve through an analysis of public HCP data and methodological experiments at 7 Tesla. We conclude that the choice of phase encoding direction can dramatically impact the fidelity of cranial nerve tractography results, and that spatial resolution plays an important role in CN-V branch identification. |
| 3381 | Computer 43
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Fibre Tracking of the Arcuate Fasciculus at High Spatial and Angular Resolution |
1Sydney Translational Imaging Laboratory, Heart Research Institute, The University of Sydney, Sydney, Australia, 2GE Healthcare, Melbourne, Australia, 3Department of Radiology, Mayo Clinic, Rochester, MN, United States, 4GE Global Research, Niksayuna, NY, United States, 5Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia |
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We compared fibre tracking performance in the arcuate fasciculus across a range of angular resolutions, as well as a low distortion dataset using diffusion MRI data from a Compact 3T scanner with high-performance gradients. Tracking performance increased approximately linearly with greater angular resolution. Performance was also improved using a low-distortion diffusion sequence at a single relatively low angular resolution acquisition (33 directions). |
| 3382 | Computer 44
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Altered structural connectivity in the auditory-related pathway in patients with idiopathic sudden sensorineural hearing loss by diffusion spectrum imaging |
1Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China, 2MR Scientific Marketing, Siemens Healthcare, Beijing, China, 3Department of Hyperbaric Oxygen, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China |
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Sensorineural hearing loss is increasingly recognized as the result of alterations in the auditory-related network. The present study aimed to further explore the whole brain abnormalities of neural network connections in idiopathic sudden sensorineural hearing loss (ISSNHL) through diffusion spectrum imaging. It was found left-sided ISSNHL exhibited decreased connectivity between the contralateral inferior temporal gyrus and rolandic operculum, and the contralateral heschl gyrus and superior marginal gyrus; while increased connectivity was detected between the ipsilateral temporal pole and cuneus, which suggests that DSI could help investigate the structural correlates of these imaging abnormalities in this disease. |
| 3383 | Computer 45
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A surface-based shape analysis of the human corticospinal tract |
1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada |
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Traditionally, when examining bundles, comparative methods between measures such as volume, streamline density and mean fractional anisotropy are often used. However, these measures can be biased and do not inform about shape of the white matter bundle. In this work, a new method is proposed to compare bundles based on its surface. Indeed, three measures (area, elongation, irregularity) applied along the cross-sections of the surface enable to highlight shape differences. Here, we illustrate the potential of these surface-based shape measures on the right and the left pyramidal tract in a healthy group of 30 datasets. |
| 3384 | Computer 46
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DIPY Horizon: fast, modular, unified and adaptive visualization |
1Intelligent Systems Engineering, Indiana University, Bloomington, IN, United States, 2Microsoft Research, Montreal, QC, Canada, 3Microsoft, Hyderabad, India, 4Université de Sherbrooke, Sherbrooke, QC, Canada, 5Indian Institute of Technology, Hyderabad, India, 6Pervasive Technology Institute, Indiana University, Bloomington, IN, United States |
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DIPY Horizon is fast, modular, unified and adaptive visualization system that resembles a high-end game engine, works on the web and across desktop operating systems. Horizon is suitable both for user, programmers and clinical applications. |
| 3385 | Computer 47
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On the regression of intracranial volume in Fixel-Based Analysis |
1The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia, 2The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Heidelberg, Australia |
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Fixel-Based Analysis (FBA) enables robust whole-brain statistical analysis of both microscopic and macroscopic white matter properties that is both sensitive and specific to crossing fibre geometry. Given the influence of macroscopic brain differences in such experiments, interest has been expressed in how best to account for variations in brain volume across participants. Here we demonstrate the effect of brain volume on FBA by synthetically modulating brain sizes within a healthy cohort and statistically testing FBA metrics with various regressions of estimated intracranial volume. We conclude with recommendations for regression of the influence of global brain size differences in FBA when desired. |
| 3386 | Computer 48
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Automated Segmentation of the Cortical Boundaries in Native Diffusion Tensor Imaging Space to Measure Anisotropy of the Cerebral Cortex |
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada |
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Diffusion tensor imaging (DTI) can quantify anisotropic diffusion in the cerebral cortex reflecting its microstructural architecture. However, the analysis is usually performed by defining the inner and outer cortical boundaries on 3D T1-weighted images which are then applied to co-registered DTI, but this is prone to registration errors. Here we present an automatic cortical boundary segmentation method applied directly to 1.5 mm isotropic DTI acquired in 6 minutes at 3T. The cortical surfaces derived from DTI alone demonstrate the radial orientation of the primary eigenvector and appropriate FA/MD showing promise for DTI studies of the cortex in neurological disorders. |
| 3387 | Computer 49
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Spatial Normalization of Fiber Orientation Distribution (FOD) Maps using Mrtrix and an Image-based Non-uniform Gradient Method |
1Center for Biomedical Imaging (CBI), Department of Radiology, New York University School of Medicine, New York, NY, United States |
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Diffusion MRI based fiber orientation distribution (FOD) estimates are widely used to examine structural connectivity in the brain. For group comparison using nonlinear spatial normalization, FOD needs to be adjusted based on the estimated degree of rotation and scaling at each voxel. We compared the current method implemented in Mrtrix for spatial normalization of FODs with an image-based method. The results suggest that the method in Mrtrix is accurate for rotation but generates potential bias in FOD peak amplitude and orientation when large anisotropic scaling is present. This knowledge is important for studies to use spatially normalized FOD maps. |
| 3388 | Computer 50
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Characterization of the cerebro-cerebellar loop exploiting advanced tractography and dealing with thalamic synapsis |
1Neuroradiology Unit, Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy, 2Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 3School of Aerospace Mechanical and Mechatronic Engineering, University of Sydney, Sydney, Australia, 4Sydney Imaging, University of Sydney, Sydney, Australia, 5Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy, 6Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 7Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy |
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Recently, advanced tractography has been used for assessing the feasibility of characterizing cerebro-cerebellar loop, composed of cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways, acknowledging the issue of how tractography deals with polysynaptic connectivity, i.e. at thalamic level. In this work, polysynaptic cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways were reconstructed using a multiplicative hypothesis for thalamic connectivity. Our findings revealed the importance of using such a multiplication factor for streamlines reaching the thalamic synapses to properly reconstruct cerebro-cerebellar connection. Furthermore, findings using polysynaptic tracts support the cerebellar role in cognition showing that cognitive/associative areas are the mainly involved in both the cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways. |
| 3389 | Computer 51
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Distortion dominates fibre tracking of the optic chiasm – an evaluation of ultra-high angular resolution compared to low-distortion diffusion MRI on a Compact 3T |
1Sydney Translational Imaging Laboratory, Heart Research Institute, University of Sydney, Sydney, Australia, 2GE Healthcare, Richmond, Melbourne, Victoria, Australia, 3GE Global Research, Niskayuna, NY, United States, 4Department of Radiology, Mayo Clinic, Rochester, MN, United States, 5Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia |
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We evaluated the impact of angular resolution and spatial distortion on crossing-fibre tracking accuracy at the optic chiasm using diffusion MRI data from a Compact 3T scanner with high-performance gradients. Contralateral tracking via the chiasm was quantified in acquisitions optimised for q-space resolution or low distortion and compared to the known true rate of decussation. We found that, for chiasmal tracking, minimising the effects of geometric distortion may provide better value than maximising spatial or angular resolution beyond 140 directions. An ideal future diffusion MRI protocol will combine these features for more optimal tracking performance. |
| 3390 | Computer 52
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Compensation of signal loss induced by scanner table vibrations in high b-value DW-TSE for measuring lipids ADC |
1Department of Diagnostic and Interventional Radiology, Technical University Munich, Munich, Germany, 2Health Systems Philips Schweiz, Zurich, Switzerland, 3Clinic of Orthopaedic Surgery, Technical University Munich, Munich, Germany |
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Fat plays a central role in the incidence of metabolic syndrome but current MRI biomarkers cannot answer questions about fat cell microstructure. Diffusion-weighted measurements are capable of revealing information about fat tissue microstructure but the required strong diffusion weighting induces scanner table vibrations that eventually lead to measurement errors and artifacts. The purpose of this work was to mitigate vibration artifacts by placing a vibration compensation gradient before the diffusion preparation. The approach was tested in a water-fat phantom and in-vivo in the lower leg of a healthy volunteer. |
| 3391 | Computer 53
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Diffusion Gradient Nonlinearity Correction in a Diffusion Phantom and in Breast Cancer Bone Metastases |
1Department of Radiology, Aarhus University Hospital, Aarhus, Denmark, 2Department of Oncology, Aarhus University Hospital, Aarhus, Denmark |
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The purpose was to investigate if diffusion gradient nonlinearity (DGNL) ADC-errors could be corrected in vitro and in vivo.
Methods DWIBS was performed in a diffusion phantom and in breast cancer patients. ADC-maps with and without DGNL correction were created and compared at different positions relative to the isocenter.
Results In the diffusion phantom uncorrected ADC-values 17.5cm from the isocenter dropped by 29-32% while the corrected ADC-values increased by 2-4%. In 85 bone metastases uncorrected ADC-values 14cm from the isocenter dropped by 18.7% while corrected ADC-values dropped by 2.8%.
Conclusion DGNL ADC-errors can be corrected in vitro and in vivo. |
| 3392 | Computer 54
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Noise2Noise MRI for High-resolution Diffusion-weighted Imaging of the Brain: Deep Learning-based denoising without need for Highly Averaged Ground-truth Images |
1Department of Radiology, University of Yamanashi, Chuo-shi, Japan |
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Deep learning (DL)-based denoising is promising to achieve high resolution diffusion-weighted imaging (HR-DWI) by improving SNR without signal averaging. Training supervised DL-based algorithm, however, requires thousands of teaching data, which need long acquisition time. In this study, we propose to use noise2noise (N2N) theory to develop DL-based denoising algorithm, which does not need teaching data with high SNR. In the results, the proposed method (N2N-MRI-based algorithm) outperformed conventional ground-truth-based algorithm in terms of maximum peak SNRs on validation sets during training. The image quality of HR-DWI denoised by N2N-MRI-based algorithm was equivalent to that denoised by conventional algorithm. |
| 3393 | Computer 55
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Iteration-based motion compensation method for multi-shot diffusion imaging |
1School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, Guangzhou, China, 2School of Medicine, South China University of Technology, Guangzhou, China, 3Guangdong General Hospital, School of Medicine, South China University of Technology, Guangzhou, China, 4Philips Healthcare, Guangzhou, China, 5Division of Superconducting Magnet Science and Technology, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, 6Laboratory of Biomedical Imaging and Signal Processing, University of Hong Kong, Hongkong, China, 7Neusoft Medical System, Shanghai, China |
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Multi-shot EPI technique is vulnerable to patient motion. Though CIRIS proposed by our group tackles the infrequent macroscopic motion in multi-shot EPI by clustering and registration, it cannot deal with the frequent motion (e.g. shot-wise motion). In this work, an iterative motion compensation frame was introduced to correct for the frequent motion during the multi-shot acquisition. The simulation experiments demonstrated that the proposed method can obtain improved image quality in the presence of infrequent motion, and even correct for the shot-wise motion, compared to CIRIS. |
| 3394 | Computer 56
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Impact of processing options on histogram metrics extraction from DWI in cerebral small vessel disease |
1Department of Bioengineering, ISR-Lisboa/LARSyS, Instituto Superior Técnico - Universidade de Lisboa, Lisbon, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisbon, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal, 5Imaging Department, Hospital da Luz, Lisbon, Portugal |
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Biomarkers based on diffusion-weighted imaging (DWI) have been proposed as potential disease biomarkers in several brain conditions including cerebral small vessel disease (SVD). Often histogram-based metrics are extracted, but findings across studies are somehow inconsistent. Here, we investigated the impact of several processing options for extracting histogram metrics of fractional anisotropy (FA) and mean diffusivity (MD) from DWI. We considered two white matter regions-of-interest with different interpolation and thresholding options, as well as different numbers of bins. We found that processing options significantly impacted histogram metrics, which in some cases significantly affects the ability to discriminate between patient and controls. |
| 3395 | Computer 57
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Corrupted Data Rejection Strategy in k-space Based Multi-shot Diffusion Reconstruction |
1China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, 2Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, 3Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 4Philips Healthcare, Beijing, China, 5Department of Radiology, University of Washington, Seattle, WA, United States |
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In diffusion imaging, bulk and physiological motion together with strong diffusion encoding gradient introduces extra image phase or data corruption in the diffusion-weighted images. Corrupted data identification/rejection procedure has not been integrated in the recently proposed k-space based multi-shot diffusion reconstruction pipelines. In this work, two corrupted data rejection strategies were proposed, compared and evaluated. Results show that using corrupted data identification and rejection after the CK-GRAPPA reconstruction is potentially a robust choice for multi-shot diffusion imaging reconstruction. |
| 3396 | Computer 58
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Correction of systematic errors in DTI imaging caused by gradient nonlinearity using gradient field maps measured by diffusion imaging of an isotropic diffusion phantom. |
1Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, United States, 2Vanderbilt University Medical Center, Nashville, TN, United States |
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Gradient nonlinearity causes systematic errors in the measurement of DTI parameters. These errors can be greatly reduced if the actual fields generated by the gradient coils is known. Although the gradient field maps are known to the manufacturers, many users do not have access to them. We describe a method for measuring the gradient field maps using a set of diffusion weighted images of an isotropic diffusion PVP phantom. We use the field maps to analyze a DTI study of the phantom and compare the results to analysis performed without the field maps. The results show that the method works well. |
| 3397 | Computer 59
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Motion Compensation for Free-Breathing Diffusion-Weighted Imaging (MoCo DWI) |
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany, 4Medizinische Fakultät Heidelberg, Heidelberg University, Heidelberg, Germany |
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Diffusion-weighted imaging (DWI) of the abdomen has acquisition times of several minutes. For this reason respiratory motion can cause misalignment between acquired slices at the same position but different b-values. To overcome this, we estimate the patients’ respiratory motion using a T1-weighted, stack-of-stars GRE pulse sequence and an advanced 4D reconstruction. This motion estimation is used to compensate for respiratory motion in a common, free-breathing DWI acquisition. In three volunteers an improved alignment of structures in the liver are shown. This allows for a better comparison and potential benefits for further processing (e.g. for ADC-maps). |
| 3398 | Computer 60
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Effects of Gradient Nonlinearities on Reproducibility and Accuracy of Diffusion MRI Metrics in the Brain. |
1Quantitative Medical Imaging/NIBIB, National Institutes of Health, Bethesda, MD, United States |
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Gradient nonlinearities in MRI cause spatially-varying b-values and diffusion gradient directions. In this work, we analyze whether these nonlinearities have a significant impact on data reproducibility and accuracy for brain studies. Our results indicate that not only FA and TR values have an increasing bias away from the isocenter of the magnet, but also differences in subject positioning and head orientation combined with nonlinearities have a significant effect on reproducibility. The effects were also observed in principal eigenvector directions computed with the tensor model. |
| 3399 | Computer 61
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Progress toward on-line implementation of vendor-provided prospective correction for non-uniform diffusion weighting due to gradient nonlinearity |
1Radiology, University of Michigan Health System, Ann Arbor, MI, United States, 2Philips Research Laboratories, Cambridge, MA, United States, 3GE Global Research, Niskayuna, NY, United States, 4Siemens Medical Solutions, Cary, NC, United States, 5Philips MR Clinical Science, Best, Netherlands, 6Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 7Radiology and Radiological Science, John Hopkins University School of Medicine, Baltimore, MD, United States |
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Feasibility of the prospective correction for non-uniform diffusion weighting due to gradient nonlinearity using scanner-specific gradient design information was previously demonstrated by our academic-industrial partnership (AIP). Here we report on the progress toward implementation of the prospective correction by leading MRI vendor participants of the AIP on their respective scanner platforms. The vendor-provided on-line correction is benchmarked by comparison to previously validated retrospective off-line processing for uniform gel and flood phantoms, and a human volunteer. Vendor efforts enable comprehensive bias correction for standardization of quantitative DWI applications in multi-center clinical trial environments. |
| 3400 | Computer 62
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Gradient nonlinearity-induced bias calibration and correction in diffusion imaging using DIADEM and a simple, uniform gel phantom |
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2GE Global Research, Niksayuna, NY, United States |
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This study reports a novel gradient nonlinearity (GNL) calibration approach using DIADEM (Distortion-free Imaging Approach with a Double Encoding Method) diffusion imaging. Unlike standard diffusion-weighted echo-planar-imaging (DW-EPI), DIADEM is free from DW-EPI distortions. This allows GNL calibration with a uniform phantom, since confounding effects between DW-EPI and GNL-induced distortions in the calibration are separated. Direct bias correction could be applied to the corresponding in-vivo data from the DIADEM scans, which results in reliable quantitative diffusion imaging. The feasibility was successfully demonstrated in phantom and in-vivo on a compact 3T system. |
| 3401 | Computer 63
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Evaluation of an adapted DWI MRI for improved image quality and tissue differentiation in abdominal MRI – a prospective study in oncologic follow-up examinations |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany, 4Siemens Healthcare GmbH, Erlangen, Germany |
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Diffusion-Weighted imaging is a mainstay for oncologic examinations. However, abdominal examinations with standard DWI can be challenged by signal exploration and motion artifacts. This prospective study therefore compares a standard EPI-DWI with an oncologically optimized-DWI, including complex averaging, motion correction between averages, rescaling of motion corrupted averages, and background suppression, in oncological follow-up MRI investigations. A diffusion resolution phantom demonstrated an improved image quality by the optimized-DWI. Image quality analysis of prospectively acquired abdominal DWI MRI examinations in 52 patients showed a significant improvement in image quality and apparent signal-to-background-noise-ratio by optimized-DWI as compared to standard EPI-DWI in oncologic imaging. |
| 3402 | Computer 64
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Learned Gibbs Removal in Partial Fourier Acquisitions for Diffusion MRI |
1Radiology, NYU School of Medicine, New York, NY, United States |
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Despite significant advances in both denoising and Gibbs artifact removal, in acquisitions such as partial Fourier encoding, noise and Gibbs ringing continue to be an issue. Here we demonstrate that a machine learning approach can extend Gibbs ringing and noise removal to partial Fourier image acquisitions and show results on estimates of diffusion parameters on phantom and brain imaging data. |
| 3403 | Computer 65
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An independent phase-based measure for slice outlier rejection in diffusion MRI |
1Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom |
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Detecting and downweighting damaged slices is vital in analysing motion-corrupted dMRI data. Conventional magnitude-based outlier rejection methods rely on intensity model predictions, with the state of the art using slice-to-volume reconstruction. However, in cases with very high outlier prevalence such model prediction is no longer reliable. Here, we introduce a model-independent phase-based measure for detecting motion-induced slice dropouts. We demonstrate its use in neonatal data, and show that it outperforms model-based magnitude techniques in highly damaged data. |
| 3404 | Computer 66
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Noise Estimation and Bias Correction of Diffusion Signal Decays: Application to Prostate Diffusion Imaging |
1Radiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden, 2Zenuity, Gothenburg, Sweden, 3Radiology, Brigham and Women's Hospital, Boston, MA, United States |
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A novel approach to estimate noise and Rician signal bias in diffusion MRI magnitude data is proposed. Rather than relying on repeat measurements for estimation of noise and expected signal, the methods uses multi-b measurements and non-monoexponential signal fits. In addition to noise and bias estimation this approach also provides signal averaging over all b-factors and permits determination of non-monoexponential tissue water diffusion signal decay. Testing was performed with Monte-Carlo simulations and on diffusion-weighted high-b prostate image data obtained with an external coil array. |
| 3405 | Computer 67
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Correction of motion artifacts in head and neck diffusion-weighted MRI |
1Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, Netherlands, 2Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands, 3Department of Medical Informatics, Erasmus MC, Rotterdam, Netherlands |
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Diffusion-weighted imaging (DWI) is a promising technique for early stratification of responders and non-responders in head and neck chemoradiotherapy. However, data corruption due to swallowing and misalignment reduce the precision of estimated DWI parameters. We investigated different post-processing approaches to improve the reproducibility of the apparent diffusion coefficient (ADC) and demonstrated an improvement in reproducibility from 13.2% to 6.7%. Inter-volume registration showed the largest improvement compared to intra-volume registration and swallowing artifact rejection. The 6.7% reproducibility is sufficient for stratification of responders and non-responders in H&N chemoradiotherapy. |
| 3406 | Computer 68
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Deep Learning based displacement transform estimation for EPI distortion correction |
1GE Global Research, Bangalore, India, 2GE Global Research, Niskayuna, NY, United States |
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In this work, we propose a DL methodology to estimate the displacement field transform (DL_DispMap) from distorted DWI-EPI images. Compared to direct estimation of distortion-free images, we establish that DL_DispMap provides better training accuracy and mitigates the smoothening effect noticed in DL_Direct. The DL_DispMap corrected images are well matched (SSIM = 0.97) to gold-standard INVERSION method based distortion-free images in performance but might be needed to be tuned for an anatomy and system configuration. The method can potentially be also applied for fMRI studies |
| 3407 | Computer 69
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Validation of an image-based measurement of gradient non-linearity method and voxel-wise correction of b-values in a HARDI dataset |
1Laboratory for Social and Neural Systems Research, University of Zürich, Zürich, Switzerland, 2Institute for Biomedical Engineering, ETH Zürich, Zürich, Switzerland, 3Brain Imaging Centre, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary, 4Department of Nuclear Techniques, Budapest University of Technology and Economics, Budapest, Hungary, 5Brain Imaging Centre, Goethe University Frankfurt, Frankfurt, Germany, 6Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 7Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, United Kingdom |
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Diffusion MRI requires numerous corrective steps in the data processing pipeline. One such step regards the need for voxel-wise correction of erroneous b-values that ensue from the inherent non-linearity of the magnetic field gradients. To estimate the non-linearity we used a simple image-based method that involves a spherical water phantom to measure voxel-wise the apparent diffusion constant. Deviations from the expected value allow estimation of the local b-value. The b-value maps were validated against the spherical harmonic predictions and subsequently used to correct phantom and in-vivo data. |
| 3408 | Computer 70
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Minimization of Nyquist ghost artifacts for diffusion-weighted single-refocused spin-echo EPI |
1Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany |
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In diffusion-weighted (DW) imaging with EPI readout, Nyquist ghost (NG) artifacts might be aggravated due to higher order eddy currents, especially when using monopolar DW gradients in single-refocused spin-echo EPI (srSE-EPI). Both linear and point-by-point phase corrections were tested on DW-srSE-EPI and, for comparison, also on DW twice-refocused spin-echo EPI (trSE-EPI) with intrinsic eddy-current compensation. Both phase correction methods performed equally well for DW-trSE-EPI. However, for DW-srSE-EPI with high b-values, the linear phase correction failed to fully correct NG artifacts. In contrast, point-by-point phase correction yielded considerably better results. This was confirmed in vitro and in vivo. |
| 3409 | Computer 71
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HARDI denoising with mean-curvature enhancement PDE on SE(3) |
1SCIL, Université de Sherbrooke, Sherbrooke, QC, Canada, 2CASA, Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Netherlands |
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We present a new High Angular Resolution Diffusion-weighted Imaging (HARDI) mean-curvature enhancement (MCE) on the homogeneous space of positions and orientations, embedded in the rigid body motion group SE(3). Its potential for crossing-preserving enhancement of fiber orientation distribution (FOD) fields is demonstrated. Compared to previous partial differential equation (PDE) enhancements on SE(3), denoising FOD fields with MCE better preserve boundaries, resulting in a lower overall angular error. |
| 3410 | Computer 72
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QC-Aautomator: A deep learning based automated artifact detection in dMRI data |
1Penn Patho-Connectomics Lab, Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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We have developed a deep learning based automated Quality Control (QC) tool, QC-Automator, for diffusion weighted MRI data, that will detect different artifacts. This will ensure that appropriate steps can be taken at the pre-processing stage to improve data quality and ensure that these artifacts do not affect the results of subsequent image analysis. Our tool based on convolutional neural nets has 94 – 98% accuracy in detecting the various artifacts including motion, multiband interleaving artifact, ghosting, susceptibility, herringbone and chemical shift. It is robust and fast and paves the way for efficient and effective artifact detection in large datasets. |
| 3411 | Computer 73
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D-stripe: correction for stripe artefacts in diffusion MRI using a combined deep neural network and SVR approach |
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 3Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, King's College London, London, United Kingdom |
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We present a data-driven method for the correction of stripe artefacts in multi-shell diffusion data that might arise for example from spin-history or stimulated echo effects. It relies on a filter, based on a deep neural network trained with simulated data to detect and remove stripe artefacts from single volumes. This is used to destripe signal predictions obtained from a slice to volume reconstruction, which are then projected onto the input data to determine the appropriate modulation field. The corrected input data are then reconstructed again with reduced stripe artefacts. This approach is applied to super-resolution reconstructions of neonatal multi-shell high angular resolution data. |
| 3412 | Computer 74
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Distortion Correction of Multi-Shot Diffusion-Weighted Echo-Planar Imaging using Reversed Gradient Acquisition and Joint Reconstruction |
1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China, 2The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China, 3Philips Healthcare, Hong Kong, China |
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Multi-shot diffusion-weighted echo-planar imaging (DW-EPI) with multiplexed sensitivity encoding (MUSE) is a self-navigated technique that can achieve high resolution diffusion-tensor imaging (DTI) without the need of navigator echo. However, even with multi-shot acquisition, the effective echo spacing is still relatively long for acquisition of high resolution DTI, leading to significant geometric distortion. In this study, we aim to reduce the geometric distortion of multi-shot DW-EPI by 1) integrating the reversed gradient acquisition in multi-shot DW-EPI, and 2) developing a joint reconstruction method that can reconstruct non-uniform k-space data by taking the off-resonance effect into account. |
| 3413 | Computer 75
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Dual-echo blip reversed EPI acquisition enables distortion correction in the presence of motion in diffusion-weighted MRI |
1Boston Children's Hospital and Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States |
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Slice-to-volume registration methods have been shown to provide motion robust reconstruction for large and frequent motions. One challenge with motion correction is the changing magnetic field inhomogeneities with different head positions. In this work we implemented a dual-echo blip reversed EPI acquisition and show that this sequence can be used to reduce distortions in large and frequent motions and can improve slice-to-volume registration results. |
| 3414 | Computer 76
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Mapping anatomical connectivity: a Structural Network Analysis in Early and Profoundly Deaf people. |
1CIMeC, Center for Mind/Brain Sciences, University of Trento, Rovereto (TN), Italy, 2Athinoula A. Martinos Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 3Institute of Research in Psychology (IPSY) and in Neuroscience (IoNS), University of Louvain, Louvain-la-Neuve, Belgium |
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In case of early acquired deafness, auditory deprived temporal regions massively enhance their response to stimuli from remaining senses. This so called cross-modal plasticity also alters functional connectivity between reorganized temporal regions and those from preserved senses. The extent and distribution of white matter structural alterations supporting these functional effects are still poorly understood. In this diffusion MRI study, we investigate white matter reorganization of early deaf relative to hearing controls. Further, since early deaf typically become fluent at sign language, which may itself also induce brain structural reorganization unrelated to deafness, we also include a group of hearing signers. |
| 3415 | Computer 77
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Structural connectivity between cerebellum and cerebral cortex in idiopathic generalized epilepsy: a diffusion tensor imaging study |
1University of Electronic Science and Technology of China, Chengdu, China |
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Probabilistic tracking method was applied to study the cerebellar efferent and afferent fibers in the patients with idiopathic generalized epilepsy (IGE), trying to address the structural connectivity (SC) alteration in the |
| 3416 | Computer 78
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Difference in Tensor Metrics between the Survived and Infarcted Penumbra by Reperfusion in a Rat Model of Cerebral Ischemia |
1Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan, 2Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 3Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan, 4Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan, 5Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, 6Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, 7Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan |
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We demonstrated |
| 3417 | Computer 79
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Graph-based Structural Connectivity is correlated with Children Intelligence Quotient Scores |
1Université Claude Bernard-Lyon 1, lyon, France, 2American University of Beirut, Beirut, Lebanon, 3Hôpital Neurologique, Hospices Civils de Lyon, Bron, France, 4CERMEP - Imagerie du Vivant, Bron, France |
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The neural substrate of high intelligence performances remains not well understood. We propose to investigate the structural brain connectivity measurements and their relationship with the intelligence performances, as measured by the WISC-IV scores of 57 children. We found strong correlations between children brain network density and intelligence scores. Moreover, several correlations were found between integration and redundancy graph metrics suggesting that intelligence performances are probably related to homogeneous network organization. |
| 3418 | Computer 80
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High-Resolution FLAIR DTI Tractography of the Fornix in Multiple Sclerosis |
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada |
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Diffusion tensor imaging (DTI) tractography of the human fornix is biased by partial volume effects from cerebrospinal fluid (CSF) due to its small bundle size and intra-ventricular location, even when using high spatial resolution. These errors in diffusion parameter estimation and tracking of the fornix will worsen with axonal loss in multiple sclerosis (MS). Here we demonstrate the superiority of FLAIR-DTI, even when compared to high-resolution 1.5 mm isotropic DTI, to mitigate CSF contamination of fornix tractography in MS and healthy volunteers. FLAIR-DTI yields more accurate diffusion metrics in both cohorts, and still shows abnormal fornix in MS. |
| 3419 | Computer 81
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Brain White Matter Abnormality Induced by Chronic Spinal Cord Injury in the Pediatric Population: A Tract Based Spatial Statistic Study |
1Thomas Jefferson University, Philadelphia, PA, United States |
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Few studies have quantified the change in cortical white matter tracts following chronic spinal cord injury in a pediatric population. Additionally, no work has been done to compare chronic SCI subjects with different American Spinal Injury Association Impairment (AIS) scale classifications. We hypothesized that these cortical changes can be detected using tract-based spatial statistics (TBSS). Our efforts revealed that significant changes in fractional anisotropy occur in several motor and sensory related regions. We conclude that TBSS can be effectively used to identify alterations in brain microstructure in a chronic pediatric spinal cord injury population. |
| 3420 | Computer 82
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Measuring white matter damage in different types of MS |
1Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States, University City, MO, United States, 2Radiology, Washington University School of Medicine, St. Louis, MO, United States, University City, MO, United States, 3Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States, 4Chemistry, Washington University in St. Louis, st louis, MO, United States, 5Radiology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States |
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A new diffusion histology imaging (DHI) is proposed to model intra and extra axonal diffusion along with isotropic diffusion within an image voxel of diffusion-weighted MR images. It resolves crossing fibers while more accurately detecting and quantifying axonal injury, axon loss, demyelination, edema and inflammation. Through the multiple-tensor modelling of diffusion-weighted MRI signals, DHI has shown the potential to detect underlying pathologies of normal appearing corpus callosum in all clinical subtypes of multiple sclerosis. |
| 3421 | Computer 83
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Evaluating Neurite Density and Orientation in the White Matter of Youth Born with Congenital Heart Disease |
1Advances in Brain & Child Development Research Laboratory, Research Institute of the McGill University Health Centre, Montreal, QC, Canada, 2Sherbrooke Connectivity Imaging Lab, Université de Sherbrooke, Sherbrooke, QC, Canada, 3MR Clinical Science, Philips Healthcare, Markham, ON, Canada, 4Division of Cardiology, Montreal Children's Hospital, Montreal, QC, Canada, 5Division of Radiology, Montreal Children's Hospital, Montreal, QC, Canada, 6School of Physical & Occupational Therapy, McGill University, Montreal, QC, Canada |
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In this study, neurite orientation dispersion and density imaging (NODDI) was used to quantify neurite density and orientation in white matter tracts in youth born with congenital heart disease (CHD). Neurite density index was significantly lower in youth born with CHD as compared to control youth in numerous, widespread association tracts. There were no regional differences in orientation dispersion index that survived correction for multiple comparisons. Our findings suggest a predominant role for lower neurite density, rather than lower neurite coherence and organization, in the white matter abnormalities observed in youth born with CHD. |
| 3422 | Computer 84
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Structural brain connectivity network alterations following mild traumatic brain injury |
1Turku Brain and Mind Center, University of Turku, Turku, Finland, 2Department of Neurology, University of Turku, Turku, Finland, 3Division of Clinical Neurosciences, Traumatic Brain Injury Centre, Turku University Hospital, Turku, Finland, 4Turku PET Centre, Turku University Hospital, Turku, Finland, 5Department of Radiology, University of Turku, Turku, Finland |
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We used graph theoretical analysis to investigate structural brain connectivity networks in mild traumatic brain injury (mTBI). Global and local measures of structural connectivity were investigated in acute/sub-acute and chronic phases after TBI. There were no statistically significant differences in the global network measures between patients and controls at either of the stages after TBI. Node-level differences were found between patients and controls in local efficiency, strength, and betweenness centrality in several brain regions. However, only betweenness centrality in the right pars opercularis endured the Bonferroni correction for multiple comparisons. |
| 3423 | Computer 85
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White matter Fractional Anisotropy measures in Autism Spectrum Disorder. Implications of differences in structural correlation with performance IQ measures and age. Results from EU- Autism Interventions data. |
1Forensic and Developmental Neuroscience, King's College London, London, United Kingdom, 2Natbrainlab, King's College London, London, United Kingdom, 3Neuroimaging, King's College London, London, United Kingdom |
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We present voxel-wise statistics on Fractional Anisotropy from EU-AIMS diffusion imaging data on Autism Spectrum Disorder. We validate previous findings of structural white matter abnormalities in a younger cohort. Correlation analysis of white matter development with behavioural tasks points to altered functioning in ASD individuals in visuospatial reasoning tasks, consistent with the central coherence theory of autism. Cohort differences between ASD and control of white matter integrity correlation with age hint toward altered developmental trajectory in Autism Spectrum individuals. |
| 3424 | Computer 86
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White Matter Microstructural Alternations in Neuropsychiatric Systemic Lupus Erythematosus With Normal Appearing Brain Using Diffusion Tensor Imaging |
1Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan, 2College of Medicine, China Medical University, Taichung, Taiwan, 3Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Sciences and Technology, Taichung City, Taiwan, 4College of Human Development and Health, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, 5Department of Thanatology and Health Counseling, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, 6Department of Biomedical Engineering, Hung Kuang University, Taichung City, Taiwan |
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Systemic lupus erythematosus (SLE) patient has neuropsychiatric signs and symptoms, called neuropsychiatric SLE (NPSLE), usually with increased mortality and morbidity rates. There was little known about pathogenic mechanisms leading to neuropsychiatric symptoms in SLE. The aims of this study attempt to investigate diffusion tensor imaging (DTI) in detection of white matter micro-structural alternations for NPSLE patients, who had normal appearing brain in conventional MRI. By using the TRACULA analysis, we found significant differences of mean diffusivity (MD) and fraction anisotropy (FA) in several important nerve tracts between NPSLE patients and normal subjects, which would be helpful in understanding the mechanisms of NPSLE. |
| 3425 | Computer 87
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Reproducibility of the diffusion of the perivascular space in older adults with dementia. |
1University of Melbourne, Melbourne, Australia, 2Royal Melbourne Hospital, Melbourne, Australia |
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Recently, there has been interest in the glymphatic system and its role in flushing amyloid ß along with other waste products in the brain. New imaging techniques are being developed to try and measure such activity. Recently, diffusion tensor MRI was used to construct an index "DTI-ALPS" to help link dementia burden with diffusion in the perivascular space. We aimed to replicate this study in 36 patients (16 AD, 16 MCI, and 4 SMC). Significant correlations were found between DTI-ALPS and stratified Mini-Mental State Examination score. Further work is needed to evaluate the feasibility of MRI to measure glymphatic activity. |
| 3426 | Computer 88
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Multivariate characterization of brain white matter maturation related to intellectual ability in children |
1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi’an, China, 2the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi'an, China, 3MR Research China, GE Healthcare, Bei Jing, People's Republic of China, Bei Jing, China |
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Brain maturations are thought to relate to behavioral acquisitions and cognitive development. Nevertheless, in vivo investigations of such relationships remain scarce in childhood. To bridge this gap, a multivariate index (DM), which delineates the “maturational distance” between children and adults and leverages DTI-metrics complementarity, was utilized to characterize WM variation. We found that DM showed significantly negative correlations with FSIQ in children aged 4-12 yr, especially in cingulum and superior longitudinal fasciculus. Besides, left hemispheric lateralization (higher correlations with FSIQ) was also observed. Our findings suggest DM as a useful biomarker in detailing the brain WM maturation related to intelligence. |
| 3427 | Computer 89
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Alterations of brain white matter tracts in children with abnormal intelligence quotient |
1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi’an, China, 2the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi'an, China, 3MR Research China, GE Healthcare, Bei Jing, People's Republic of China, Bei Jing, China |
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Studies have shown that brain white matter microstructure is of crucial importance for intelligence. Here, we detailed the alterations of brain white matter tracts in children with abnormal intelligence quotient by comparing the difference of brain white matter tract between the two groups and exploring correlations with intelligence scores based on DTI parameters. Significant differences of ILF, IFO and SLF were found in children with abnormal intelligence quotient. And all these tracts were strongly correlated with intelligence quotient, suggesting the underlying structural origins of lower cognitive function. |
| 3428 | Computer 90
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High Spatial Resolution Multi-shell DTI in Children and Young Adults Prenatally Exposed to Alcohol |
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada |
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Diffusion tensor imaging (DTI) has identified white matter differences in individuals with prenatal alcohol exposure (PAE). The current study uses higher spatial resolution of 1.5 mm isotropic (3.4 mm3 voxels) and larger b-values of 2000 s/mm2 (in addition to typical 1000 s/mm2) to assess the brain in children to young adults with PAE. Using the ICBM DTI template regions-of-interest for white matter, the b2000 tensor metrics (but not b1000) showed group differences in the left medial lemniscus and left stria terminalis, the latter also showing correlations with age in the control group but not the PAE group. |
| 3429 | Computer 91
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A fixel-based analysis of diffusion properties of white matter fiber in Williams Syndrome |
1Neuroscience Research Australia, Sydney, Australia, 2School of Medical Sciences, University of New South Wales, Sydney, Australia, 3Centre for Research in Atypical Neurodevelopment, Macquarie University, Sydney, Australia, 4T.Y. Nelson Department of Neurology, Children's Hospital at Westmead, Sydney, Australia |
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Williams Syndrome (WS) is a genetic neurodevelopmental disorder produced by a hemideletion of around 26 genes on chromosome 7 (7q11.23) that leads to unique changes in physical and cognitive profiles. Behavioural characteristics including hyper-sociability, excessive friendliness and empathy, sensitivity to loud noises and visual-spatial construction deficits infer unique brain structure and connections. WS is also characterised by reduced muscle tone and a decrease in motor coordination and balance1. We show significant differences in the corticospinal tract in WS participants and that white matter changes previously reported are more likely to be due to morphological changes to the fiber bundles rather than microstructural ones. |
| 3430 | Computer 92
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Abnormal brain white matter volume underlying methamphetamine abusers: A machine learning approach |
1Department of Radiology, Shenzhen Mental Health Center, Shenzhen Kangning Hospital, Shenzhen, China, 2Department of Drug Dependence, Shenzhen Kangning Hospital, Medicine Division of Shenzhen University, Shenzhen, China, 3GE Healthcare, MR Research China, Beijing, China |
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The disruption of specific microstructural features of white-matter (WM) has been observed in methamphetamine (MA) abusers. However, it remains unknown whether WM volume is abnormal in MA abusers. To address this issue, a machine learning approach was applied in this study to differentiate between 21 MA abusers and 13 age- and gender- healthy controls. Our results showed that a linear support vector machine classifier achieved an accuracy of 73.53% using the white matter volume as input features. Particularly, the most discriminative WM regions included pontine crossing tract, motor system and the reading related network. |
| 3431 | Computer 93
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Diffusion MRI detects changes in the Hippocampus and Fimbria-Fornix Circuit in 2 months old 3xTg-AD mice |
1Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States, 3Department of Neurology, Medical University of South Carolina, Charleston, SC, United States, 4Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States |
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The triple transgenic mouse model (3xTg) of Alzheimer’s disease (AD) exhibits both Aβ and tau pathology. Interestingly, the first detectable pathological features in this model are alterations in overall myelination patterns leading to white matte disruption as early as 2 months of age. Here we investigated the sensitivity of diffusion MRI (dMRI) to detect brain changes in young 3xTg mice. Our results indicate that dMRI is able to capture brain microstructural alterations associated with the hippocampus-fimbria-fornix circuit in 2 months-old 3xTg-AD mice, thus demonstrating dMRI as a viable tool for studying abnormal pathology in this AD mouse model. |
| 3432 | Computer 94
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3D Diffusion MRI of Perivascular Fluid Movement: Towards Non-Invasive Mapping of Glymphatic Function. |
1Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, United Kingdom, 2The Francis Crick Institute, London, United Kingdom, 3Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, London, United Kingdom, 4Leonard Wolfson Experimental Neurology Centre, UCL Queen Square Institute of Neurology, London, United Kingdom |
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Within the glymphatic system, CSF is transported in a network of perivascular channels where it exchanges with ISF to drive drainage of unwanted solutes, like amyloid- β, out of the brain. Perivascular channel impairment may be an early biomarker of neurodegenerative processes. Here, we present a pilot study for 3D non-invasive assessment of glymphatic function in the rat brain using ultra-long echo time diffusion MRI. We show that this technique is sensitive to the fluid movement in downstream perivascular channels that drives glymphatic inflow. |
| 3433 | Computer 95
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DW-MRI and FDG-PET as an Imaging Biomarker for Biological Response to Fast Neutron Exposure |
1Division of Applied Radioisotope, Korea Institute Radiological and Medical Sciences, Seoul, Korea, Republic of |
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In this study, we monitored biological response in neutronexposed normal mouse brains using DW-MRI and 18F-FDG-PET. DW-MRI and 18F-FDG-PET were sensitive enough to detect physiological changes that were not identified in the H&E results. These results suggest that DW-MRI and 18F-FDG-PET can be used as imaging biomarkers to provide a quantitative indicator of complex in vivo pathological changes. Assessment of radiation exposure using imaging biomarkers is non-invasive and can be used repeatedly in clinical practice. In addition, it should be applied not only for evaluating the therapeutic effects of tumors, but also for evaluating the degree of tissue damage by radiation exposure. |
| 3434 | Computer 96
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Functional and microstructural alterations in the rat hippocampus after repetitive mild traumatic brain injury |
1Clinical Medicine, Aarhus University, Århus C, Denmark, 2Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark, 3John D. Dingell VA Medical Center, Wayne State University, Detroit, MI, United States |
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Repetitive mild traumatic brain injury ( |
| 3435 | Computer 97
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Structural and Functional Characteristics of the Common Marmoset Brain Assessed Using Connectome Analysis |
1Radiological Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 2Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 3Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Wako, Japan, 4Live Imaging Center, Central Institute for Experimental Animals, Kawasaki, Japan |
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Connectome analysis with magnetic resonance imaging (MRI) is a non-invasive method and is an important approach for assessing brain networks and neurological diseases from a multilateral perspective. We examined the structural and functional characteristics of the common marmoset brain using structural and functional connectome analyses. For these connectome analyses, diffusion-weighted imaging and true-awake resting-state functional MRI (rsfMRI) were performed using a 9.4-T MRI scanner. The structural connectome analysis showed that the visual region had the most prominent structural characteristics in the marmoset brain. In addition, functional connectome analysis indicated that the functional connectome results were affected by the rsfMRI environment. |
| 3436 | Computer 98
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Ex vivo Structural Connectomics of the Mouse Brain Subcortical Regions |
1GAIST, Incheon, Korea, Republic of, 2Lee Gil Ya Cancer & Diabetes Institute, Incheon, Korea, Republic of |
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Parkinson's disease (PD) is one of the degenerative brain disease and the hallmark of PD is the death of dopaminergic cells. The subcortical area involved in neuronal circuits which play a central role in the motor control. Structural connectivity can identify abnormal connectivity of neural circuits. Diffusion tensor imaging (DTI) is a non-invasive technique that has been used to delineate the internal anatomy by tracing white matter tracts. In this study, we investigated ex vivo diffusion MR images using perfusion methods and identify the structural connectivity in subcortical regions. In conclusion, we provide structural connectional fingerprints in the mouse model. |
| 3437 | Computer 99
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Readout segmented EPI based Relative apparent diffusion coefficient in early monitoring the treatment effect of low-intensity transcranial ultrasound: evaluation in a rat permanent occlusion model |
1Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China, 2Graduate School of Hebei Medical University, Shijiazhuang, China, 3MR Scientific Marketing, Siemens Healthcare, Beijing, China |
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Acute ischemic stroke is a common and frequently occurring disease that severely harms human health and has high morbidity and mortality. Low-intensity transcranial ultrasound (LIPUS), due to its advantages of higher spatial resolution and greater penetration depth, has emerged as a new modality for noninvasive neuromodulation. This study indicated that the rADC based on readout segmented EPI sequence is a good indicator to evaluate the curative effect of LIPUS on acute cerebral infarction treatment. |
| 3438 | Computer 101
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Comparison of IVIM Model, Kurtosis Model and IVIM-Kurtosis Model for the Grading of Hepatocellular Carcinoma |
1Beijing Hospital, Beijing, China |
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IVIM model and DKI model cover different aspects of diffusion, thus a combined IVIM-DKI model might describe diffusion in perfused biological tissues more accurately. The aim of the study was to quantitatively compare the potential of various parameters obtained from IVIM model, Kurtosis model and IVIM-Kurtosis model in the grading of hepatocellular carcinoma (HCC). We enrolled 24 HCC patients who underwent multiple b values Diffusion-Weighted Imaging (DWI) with subsequent pathological confirmation. Our results showed that all three models could differentiate high-grade HCC from low-grade HCC and IVIM-Kurtosis model may be superior to IVIM model. |
| 3439 | Computer 102
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Correlation between IVIM parameters and cT1 in HCV patients |
1Dept of Physics, Vision Lab, University of Antwerp, Antwerp, Belgium, 2Fondazione Toscana "G.Monasterio", Massa, Italy, 3Perspectum Diagnostics, Oxford, United Kingdom, 4Hepatology Unit, University Hospital of Pisa, Pisa, Italy, 5Dept Clinical and Experimental Medicine, University Of Pisa, Pisa, Italy, 6Dept of Information Engineering, University Of Pisa, Pisa, Italy |
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IVIM imaging has been investigated by several researchers to understand its clinical potential. However, the dependency from b-value distribution and the effect of confounding factors such as iron and steatosis make hard to draw conclusion. In this work, a multiparametric protocol was proposed to address those confounds and the correlation with iron-corrected T1 (cT1) was studied in a group of patients affected by hepatitis C. The vascular volume fraction F shows a statistically relevant correlation with cT1 (p<0.001). |
| 3440 | Computer 103
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DTI of Spinal Cord Lesions of Varying Severity Based on MRI in the Entire Pediatric Spinal Cord |
1Thomas Jefferson University, Philadelphia, PA, United States, 2University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3Johns Hopkins School of Medicine, Baltimore, MD, United States |
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To determine whether DTI at sites cephalad and caudal to the MRI lesion provides measures of cord abnormalities in different SCI groups (n=23) compared to TD (n=36) and any correlation between the varying severity of MRI abnormality and DTI abnormalities cephalad and caudal to the MRI lesion. to the MRI lesion. The five SCI groups included; 1= SCIWORA (n=6); 2=Syringohydromyelia (n=4); 3=Atrophy+Syringomyelia (n=7); 4=Atrophy+Myelomalacia (n=3); 5=Atrophy+Hemorrhage (n=3). Groups 1 to 5 |
| 3441 | Computer 104
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Assessment of Traumatic Peripheral Nerve Injury and Carpal Tunnel Syndrome with Diffusion Tensor Imaging |
1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 4Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States |
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Clinical management following traumatic peripheral nerve injury and carpal tunnel release surgeries requires physicians to rely on qualitative measures from patient history and physical exams. The resulting delays in clinical decision-making can lead to a negative impact on patient outcomes because the regeneration of nerves must occur in a timely fashion to avoid permanent muscle atrophy and loss of sensorimotor function. The current study aims to test the feasibility of performing diffusion tensor imaging in the nerves of the wrist to provide a noninvasive and reliable tool that can monitor patient outcomes and improve clinical decision-making after surgical interventions. |
| 3442 | Computer 105
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Inter- and intraobserver reproducibility of two different delineation of intravoxel incoherent motion in differentiating benign and malignant thyroid nodule |
1MR Department, Beijing Shijitan Hospital of Capital Medical University, Beijing, China, 2Philips Healthcare, Hong Kong, China, 3Beijing Friendship Hospital, Capital Medical University, Beijing, China |
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To compare the reproducibility and diagnostic performance of IVIM parameters derived from 3D whole-lesion (W-L ROI) and single-section (S-S ROI) delineation respectively . Forty-three patients with 46 pathologically confirmed thyroid nodules were involved. Reduced FOV DWI with 2D RF was employed to decrease the distortion. The ICC values of all IVIM parameters were higher with W-L ROI delineation than with S-S ROI delineation. The 95% limits of agreement (Bland-Altman plots) determined by W-L ROI revealed smaller absolute intra- and interobserver variability and the AUC of W-L ROI delineation was higher than S-S ROI according to ROC analysis. |
| 3443 | Computer 106
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Application of Whole-Body Diffusion-Weighted MRI Imaging with Apparent Diffusion Coefficient Mapping for the Evaluation of Depth of Response to Therapy in Multiple Myeloma |
1The First Affiliated Hospital of Soochow University, Soochow, China |
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Whole-body diffusion-weighted magnetic resonance imaging (WB-DWI MRI) is an important imaging technique of great supplementary diagnostic value to the evaluation of treatment response in patients with multiple myeloma (MM). Conventional radiography which has been widely avaiable for the identification of myeloma-related bone lesions both at diagnosis and during disease course is of limited value to the assessment of response to therapy or disease relapse in MM, as lytic bone lesions rarely show signs of healing despite response to therapy. WB-DWI MRI with the measurement of apparent diffusion coefficient (ADC) value is an effective way for quantitatively comparing the differences in water diffusion among normal marrow, active pathologic marrow and that in remission. In this work, we report the preliminary results of the application of WB-DWI MRI in discriminating deep response to induction therapy for newly diagnosed MM patients. |
| 3444 | Computer 107
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Non-Gaussian IVIM-DWI for prediction of locoregional failure in nasopharyngeal carcinoma |
1Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Radiation Oncology, Dana-Farber/Brigham and Women’s Cancer Center, South Weymouth, MA, United States, 3Radiation Oncology, Memoral Sloan Kettering Cancer Center, New York, NY, United States, 4Radiation Oncology Eye, Ear, Nose & Throat, Hospital of Fudan University, Shanghai, China, 5Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States |
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The study aims to assess quantitative metrics derived from pretreatment NG-IVIM using multiple b-value diffusion weighted imaging data for predicting tumor with and without locoregional failure (LRF) in NPC patients. Kaplan-Meier method and the log-rank test were used to analyze differences between NPC patients with and without locoregional curves. Kaplan Meier results showed that the pre-treatment mean ADC and D value could predict LRF in NPC patients. The pretreatment NG-IVIM diffusion-weighted imaging will provide useful information for the selection of patients appropriate for definitive radiotherapy. |
| 3445 | Computer 108
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Increasing reader confidence in cancer imaging using an advanced DWI processing – a prospective reader study |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany |
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Diffusion-Weighted imaging (DWI) in abdominal MRI is highly valuable for oncological follow-up-investigations. However, intrinsic limitations of the method, including susceptibility to motion artifacts and poor signal in the retroperitoneum, are of special importance regarding its usage in abdominal examinations. This prospective study compared a standard EPI-DWI with an oncologically optimized prototype DWI in 59 patients with regard to the detectability/characterization of suspicious lesions. The study demonstrated that the oncologically optimized prototype DWI sequence with complex averaging, motion correction between averages, rescaling of motion corrupted averages, and background suppression, significantly increased the reader confidence for lesion characterization/detection in oncological abdominal MRI. |
| 3446 | Computer 109
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Prospective evaluation of motion correction and complex averaging in ultra-high-b-value DWI for image quality and lesion conspicuity in oncologic follow-up examinations |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany |
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In oncological, abdominal MRI, the value of motion corrected Diffusion-Weighted Imaging (DWI) including complex averaging with high and ultra-high b-values remains to be defined. This is of special importance regarding the balance between normal tissue suppression and suspicious lesion demarcation. This prospective study investigated 41 patients with an oncologically optimized prototype-DWI (with complex averaging, motion correction between averages, rescaling of motion corrupted averages, background suppression). Image quality, tissue differentiation and lesion detection/characterization were significantly increased in high (b900) as compared to ultra-high (b1500) DWI. At the same time, apparent signal-intensity ratio of lesion/normal tissue was not significantly different. |
| 3447 | Computer 110
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Whole-volume ADC Histogram and Texture Analyses of Parotid Glands as an Image Biomarker in Evaluating Disease Activity of Primary Sjögren's Syndrome |
1Radiology, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China, 2Philips Healthcare, Shanghai, China |
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Fifty-five patients with pSS underwent MRI including DWI to explore whether ADC histogram and texture analyses to evaluate the disease activity of pSS. According to the ESSDAI score, 35 patients were categorized into the low-activity group and 20 into the moderate-high-activity group. ROC analysis showed that the anti-SSB, lip biopsy, MRI morphology, ADC, ADCmean, and entropy values were able to categorize the disease into two groups, particularly the entropy values. The multivariate model, which included anti-SSB, MRI morphology and entropy, had an area under the ROC curve of 0.923. The parotid entropy value distinguished disease activity in patients with pSS. |
| 3448 | Computer 111
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Non-Gaussian Diffusion Imaging with a Fractional Order Calculus Model to predict response to neoadjuvant chemoradiotherapy in local advanced rectal cancer |
1Shanxi Province Cancer Hospital, Taiyuan, China, 2MR Clinical Sciences, Philips Healthcare Greater China, Beijing, China |
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A novel non-Gaussian diffusion model based on fractional order calculus (FROC) were successfully applied to diffusion MRI of rectal cancer. Statistically significant differences in △D and △β values are observed between the responder group and non- responder group (p < 0.01), indicating that FROC-derived parameters from the FROC diffusion model may be useful as imaging biomarkers in predicting the biological properties of rectal cancer in clinical practice. |
| 3449 | Computer 112
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Reduced field-of-view Diffusion-weighted imaging at 3T for Evaluating Allograft Fibrosis After Kidney Transplantation: A Preliminary Study |
1Department of Medical Imaging, Jinling Hospital, Nanjing Clinical School, Southern Medical University, Nanjing, China, China, 2Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China, Nanjing, China, China, 3GE Healthcare, Advanced Application, Shangha, China, Shangha, China, China |
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The extent of renal allograft fibrosis is a critical predictor of adverse allograft outcome. This institutional review board approved study included 109 renal transplantation recipients receiving 3 T multi-b reduced field-of-view intravoxel incoherent motion diffusion-weighted imaging (rFOV IVIM-DWI) examinations. The purpose of the present study is exploring the diagnostic value of evaluating allograft fibrosis with IVIM-DWI. In the present study, we have found that there is downward trend of ADCT and ADCD with the development of kidney fibrosis and both of them had good diagnostic efficiency in the distinguish fibrosis extent. |
| 3450 | Computer 113
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Diffusion time-dependence of diffusivity and kurtosis in locally advanced head and neck squamous cell carcinoma before and after chemo-radiation therapy |
1Radiology, NYU School of Medicine, New York, NY, United States, 2Radiation Oncology, NYU Langone Health, New York, NY, United States |
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Synopsis: The effect of chemo-radiation therapy on advanced head & neck squamous cell carcinoma was evaluated via diffusion and kurtosis time-dependence. We found opposing diffusion limiting regimes pre and post therapy, where prior to therapy the tissue was well described by the long-time limit (Karger Model applies), and where after therapy the tissue was well described by the short-time S/V limit. This reversal of imaging regimes can serve as a signature of the minimal effective dose required for treatment. |
| 3451 | Computer 114
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Predicting Renal Glomerular Filtration Rate of Children with Account of Kidney Compensation Using Multiple b Values Diffusion-Weighted Imaging |
1Radiology Department, Wuhan Children's Hospital, Tongji Medical College,Huazhong University of Science&Technology, Wuhan, China, 2Department of Nephrology, Wuhan Children's Hospital, Tongji Medical College,Huazhong University of Science&Technology, Wuhan, China, 3FITPU Healthcare Ltd, Singapore., Singapore |
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GFR would fail to tell the functional status of each kidney for CKD cases,so we try to use machine learning methods to predict GFR of pediatric kidneys based on the IVIM diffusion parameters. The results is that,With account of kidney compensation, averaged correlation between predicted and measured GFR up to 0.9 (p < 0.05) was obtained for the combination of perfusion-fraction f and pseudo-flow fD*. For comparison, if not taking into account kidney compensation, the best predictor attained the correlation of 0.3. We conclude that a noninvasive method can predict well the GFR of children with kidney diseases using multiple b values DWI. The best predictions involved the use of perfusion-fraction f and pseudo-flow fD* which are closely related to renal blood perfusion. |
| 3452 | Computer 115
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The performance of TGSE BLADE DWI in the diagnosis of cholesteatoma compared with RESOLVE DWI technique |
1EENT Hospital of Fudan University, Shanghai, China, 22.Scientific Marketing, Siemens Healthcare, Shanghai, China, 3Department of Digitalization, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 4Scientific Marketing, Siemens Healthcare, Shanghai, China |
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Synopsis：This study aimed to compare the performance of two diffusion weighted imaging techniques used to diagnose cholesteatoma: readout-segmented echo-planar imaging (RESOLVE) and turbo gradient spin echo (TGSE) BLADE DWI. The results showed that the TGSE BLADE DWI had better image quality with respect to reducing susceptibility artifacts, distortion, and blurring compared with RESOLVE. However, the SNR of TGSE BLADE DWI needs to be improved in the future. |
| 3453 | Computer 116
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Head and neck squamous cell carcinoma: diagnostic performance of diffusion kurtosis imaging for the prediction of histopathologic prognostic factors |
1Radiology, Peking Union Medical College Hospital, Beijing, China, 2Pathology, Peking Union Medical College Hospital, Beijing, China, 3Otolaryngology, Peking Union Medical College Hospital, Beijing, China, 4Stomatology, Peking Union Medical College Hospital, Beijing, China, 5Siemens Healthcare Ltd., Beijing, China, 6Siemens Healthcare GmbH, Erlangen, Germany |
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This preliminary study evaluated the diagnostic efficacy of diffusion parameters, derived from different models, for differentiating between tumor grades and identifying metastatic lymph nodes in head and neck squamous cell carcinomas (HNSCCs). Superior diagnostic efficiency was achieved when combining ADC values derived from a mono-exponential model with kurtosis and diffusivity values derived from a diffusion kurtosis imaging (DKI) model compared to using each parameter by itself. |
| 3454 | Computer 117
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Histogram analysis of diffusion kurtosis imaging in prostate cancer: comparison with pathology using in-bore transrectal MR-guided biopsy |
1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China |
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Our purpose was to verify the use of DKI histogram analysis for differential diagnosis of prostate cancer and noncancerous foci (benign prostatic hyperplasia and prostatitis). Twenty-three patients underwent MRI subsequently using in-bore transrectal MR-guided biopsy as the pathological reference. Our results showed DKI histogram analysis has favorable effective function and good repeatability for the differential diagnosis. DKI histogram analysis may contribute to improve the diagnostic accuracy. |
| 3455 | Computer 118
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Quantifying diffusion-weighted MRI parameters with cellular infiltration, tissue ingrowth, and angiogenesis to characterize collagen-sponge remodeling. |
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Worcester Polytechnic Institute, Worcester, MA, United States |
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In vivo evaluation of biomaterial implant remodeling involves surgical removal of the implant for subsequent histological assessment, which is often destructive and limits the effective evaluation of these materials. Diffusion-weighted MRI has the potential to non-invasively monitor the remodeling of collagen scaffolds. This study investigated the role of apparent diffusion coefficient (ADC) from different diffusion regimes to evaluate the remodeling of implanted collagen scaffolds and correlated the findings to conventional histological techniques. Correlations between ADC and histological parameters demonstrated that MRI is sensitive to specific remodeling parameters which can aid in the design of robust biomaterial scaffolds for tissue regeneration. |
| 3456 | Computer 119
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A Comparative Study of IVIM Model, Kurtosis Model and IVIM-Kurtosis Model for the Diagnosis and Aggressiveness Assessment of Prostate Cancer |
1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China |
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The purpose of our study was to quantitatively compare the utility of the parameters obtained from IVIM, kurtosis, and IVIM-kurtosis models in the differential diagnosis and aggressiveness assessment of prostate cancer, by using in-bore transrectal MR-guided biopsy as a reference. Our results displayed that IVIM, kurtosis and IVIM-kurtosis models has effective function for the differential diagnosis of prostate cancer and the diagnostic efficacy among the three models were similar. In aggressiveness assessment, IVIM-kurtosis model may be superior to the others. |
| 3457 | Computer 120
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Adapting Diffusion Weighted Arterial Spin Labelling (DWASL) to use a Single Sided Bipolar Diffusion Gradient to Probe Microvascular Signal |
1Neuroscience & Psychology, University of Glasgow, Glasgow, United Kingdom, 2University of Edinburgh, Edinburgh, United Kingdom, 3University of Glasgow, Glasgow, United Kingdom |
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Diffusion Weighted Arterial Spin Labelling uses a pair of bipolar diffusion gradients surrounding a spin echo pulse to image signal in the intravascular and extravascular compartments. We propose moving these gradients to a single sided gradient, reducing Δ and changing where the change to the extravascualar signal starts. Our results show that the ratio has changed from b = 50 to b = 300 s/mm2 for our new single sided sequence. This can give us more information on the intravascular signal, helping to improve the probing of blood brain barrier permeability. |
| 3458 | Computer 121
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Differentiation of Sinonasal Mucosal Malignant Melanomas from Sinonasal Carcinomas Using Whole-tumour Histogram Analysis of Diffusion Kurtosis Imaging and Intravoxel Incoherent Motion |
1Eye & ENT Hospital of Fudan University, Shanghai, China, 2Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 3Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 4MR Scientific Marketing, Siemens Healthcare, Shanghai, China |
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This is the first study that used histogram metrics derived from diffusion kurtosis (DKI) and intravoxel incoherent motion (IVIM) to differentiate sinonasal mucosal malignant melanomas (SNMMMs) and squamous cell carcinomas (SCCs) which are sometimes indistinguishable with conventional MRI. Overall, histogram metrics obtained from K, D, D* and f were found to be significantly higher in SNMMMs than in SCCs. Furthermore, the combined use of the two independent indicators, the 75th percentile of K and skewness of D, can effectively differentiate between SNMMMs and SCCs. |
| 3459 | Computer 122
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Quantifying diffusivity of ISFIs in vivo using DWI: A novel method to evaluate drug release |
1Basic Medical Sciences, Purdue University, West Lafayette, IN, United States, 2Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 3Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States |
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Medication effectiveness relies on patient adherence to a given treatment regimen. Often, patients do not adhere to the temporal guidelines set by their physicians and treatments therefore remain less effective. In situ forming implants (ISFIs) eliminate the need for patient adherence and release an effective dose of drug overtime. However, no methods exist to noninvasively and temporally validate drug release in vivo. We conducted in vivo experiments that validated the use of DWI to monitor ISFI diffusivity overtime. This has enormous implications in pharmaceutical research as this method can robustly quantify diffusivity in ISFIs post-implantation to ensure effective drug release. |
| 3460 | Computer 123
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Evaluation the staging of liver fibrosis using diffusion kurtosis imaging: a pilot study |
1The Second Hospital of Dalian Medical University, Dalian, China, 2The First People’s Hospital of Dalian Jinzhou, Dalian, China, 3GE Healthcare, China, Beijing, China |
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To investigate the diagnostic value of the quantitative diffusion kurtosis imaging（DKI）parameters in the staging diagnosis of liver fibrosis in rabbits’ model. Twenty-nine successful rabbit models were scanned by a 3T MR scanner (Discovery MR750W, GE，Healthcare, USA). GE AW4.6 Workstation and statistical software helps to evaluate the correlation between quantitative analysis of DKI and METAVIR staging. It is concluded that DKI related parameters might have important diagnostic value for the staging of liver fibrosis. |
| 3461 | Computer 124
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Assessment of microstructural changes during intervertebral disc degeneration by diffusion kurtosis imaging |
1Radiological Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, China, 21.Radiology Dept., 2. Bioengineering Dept., College of Medicine, University of Illinois at Chicago, Chicago, IL, United States |
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To assess the microstructural changes of intervertebral disc degeneration, 18 rats were punctured percutaneously at the intervertebral disc, and the rats’ tail was imaged with T2WI, DWI and DKI sequences. The diffusion parameters changes were consistent with the histological changes at the different time points and showed significant differences between the different groups. And, DKI parameters were better markers to detect the change of microstructure of the degenerated discs than conventional DWI. Therefore, DKI is a noninvasive technique to test the changes of the microstructure of the intervertebral discs. |
| 3462 | Computer 126
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Brain Development in Non-human Primates Assessed with Neurite Orientation Dispersion and Density Imaging |
1Department of Radiological Sciences, Human Health Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 2Live Imaging Center, Central Institute for Experimental Animals, Kanagawa, Japan, 3Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 4Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Saitama, Japan |
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Neurite orientation dispersion and density imaging (NODDI) can specifically estimate the microstructure of neurites. Brain development characteristics were evaluated using NODDI in common marmosets. The study included six common marmosets (age, 5–30 months). In NODDI, the value of both dispersion and density increased. Additionally, the trend of increase varied from region to region. This pattern has previously been observed in human studies. Thus, NODDI can be a good approach to evaluate brain development in the common marmoset, and eventually a suitable parameter to study brain developmental disorders for diagnosis and treatment. |
| 3463 | Computer 127
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Diffusion Dispersion Imaging: Mapping OGSE Frequency Dependence in the In Vivo Human Brain |
1Centre for Functional and Metabolic Mapping, Robarts research institute, Western university, London, ON, Canada |
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Oscillating gradient spin-echo (OGSE) diffusion MRI allows measurement of the frequency dependence of the apparent diffusion coefficient (ADC), which gives insight into tissue microstructure. OGSE has been utilized in numerous animal models, but its application in the in vivo human brain is challenging. Further, a parameterization that allows visualization of maps of the frequency dependence of ADC throughout the human brain has thus-far not been demonstrated. In this work, we report on an efficient method to generate maps of diffusion dispersion (DD), which characterizes the frequency dependence of the ADC, and demonstrate full-brain DD mapping in vivo at 7T. |
| 3464 | Computer 128
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Correlation Tensor Imaging (CTI): resolving diffusion sources of non-Gaussian diffusion |
1Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal, 2Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Clinical Institute, Aarhus University, Aarhus, Denmark, 3Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark |
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The cumulant expansion of Double Diffusion Encoding (DDE) involving correlation tensors has been previously theoretically presented but never exploited beyond microscopic anisotropy detection. Here, we propose the correlation tensor imaging (CTI) as novel approach capable of mapping correlation tensor features using DDE acquisitions. The correlation tensor can provide unique information: as a first step, we theoretically and experimentally demonstrate that CTI can be used to resolve the different underlying sources of diffusion kurtosis vis-à-vis isotropic and anisotropic variance of tensors and restricted diffusion (µK). The ensuing estimates bode well for many future applications. |
| 3465
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Computer 129
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Restricted diffusion in the Gaussian local phase approximation |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Neuroradiology, University Hospital Wuerzburg, Wuerzburg, Germany, 3Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany |
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Diffusion MRI is highly influenced by diffusion boundaries created by microscopic cells and blood-filled vessels. The Gaussian phase approximation is a common method to analyze the signal evolution in the presence of diffusion. However, the Gaussian phase approximation exhibits several drawbacks as it is only valid for strong diffusion effects, it does not provide phase information and it yields only the total magnetization. In this work, we generalize the traditional Gaussian phase approximation and solve the mentioned issues. The new Gaussian local phase approximation is then applied to diffusion restricted between two slabs, within a cylinder and within a sphere. |
| 3466 | Computer 130
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Diffusion kurtosis imaging as an effective predictor of liver function |
1Department of Medical Technology, Tokyo Women's Medical University Yachiyo Medical Center, Yachiyo, Japan, 2Department of Radiological Technology, Tokushima Bunri University Faculty of Health and Welfare, Sanuki, Japan, 3Department of Radiological Service, The University of Tokyo Hospital, Hongo, Japan, 4Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan |
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We evaluated whether DKI analysis as an indicator of liver function can replace laboratory tests. The mean kurtosis value was found to correlate with the Child–Pugh score and the ICG score. However, the correlation between the mean kurtosis valueand the ALBI score was the poorest among these. ADC values correlated with only the ICG score. The mean kurtosis value can be one of predictors for liver function owing to its correlation with typical indicators of liver function by serum data although this method, which shows liver function using DKI alone, cannot completely substitute the laboratory tests. |
| 3467 | Computer 131
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Single-shell diffusion MRI data with b=1000: which non-tensor models are feasible? |
1Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON, Canada, 2McMaster University, Hamilton, ON, Canada, 3University of Toronto, Toronto, ON, Canada, 4University of Calgary, Calgary, ON, Canada, 5Rotman Research Institute, Toronto, ON, Canada, 6Krembil Research Institute, Toronto, ON, Canada |
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Single-shell diffusion data with b=1000 is commonly acquired in clinically focused studies, and fit with a tensor to calculate microstructure parameters, despite that model's limitations. This study fit several multi-compartment models to such data. The most promising models were: (i) two-fiber ball-stick with a single common diffusivity parameter, which provided the most stable results, and (ii) two-fiber ball-zeppelin, which provided low-noise and stable parameter maps and dispersion values with burn-in settings above 20,000 jumps. The default model in bedpostx yielded lower quality results in this data, even with extremely long processing times. |
| 3468 | Computer 132
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Regularization stabilizes the fit of the two-compartment free water diffusion MRI model |
1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States |
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Free water mapping using single-shell diffusion MRI has been proposed by regularizing the ill-posed problem, but the effect of this regularization has yet to be systematically investigated. Here we explore the solution space for the two-compartment free water model. Without regularization, the solution space is flat for one-shell data, and while it has a minimum for two-shell data, this minimum is not particularly steep. Regularizing the fit by exploiting smoothness of the tensor creates a steep minimum in both one- and two-shell data, demonstrating the advantage of regularization. |
| 3469 | Computer 133
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Optimal subsampling of q-space for Mean Apparent Propagator MRI using a genetic algorithm |
1Department of Neurosurgery, Medical College of Wisconsins, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States |
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Mean Apparent Propagator (MAP) MRI provides a robust analytical framework to estimate the diffusion probability density function (PDF). Several scalar metrics are calculated from the PDF, which might better characterize tissue microstructure compared to conventional diffusion methods. The downside of MAP MRI is the long acquisition times of over an hour. In this study we developed a genetic algorithm (GA) to determine optimal q-space subsampling scheme for MAP MRI that will keep total scan time under 10 minutes, while preserving accuracy. Results show that the metrics derived from the optimized schemes match those from the full set closely. |
| 3470 | Computer 134
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Quantifying voxel-wise differences between diffusion propagators across multiple MAP-MRI datasets |
1National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States, 2National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States, 3Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 4Department of Surgery, University of Arizona, Tucson, AZ, United States, 5Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, MD, United States, 6Clinical Center, National Institutes of Health, Bethesda, MD, United States, 7National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States |
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We describe a technique for voxel-wise analysis across multiple mean apparent propagator (MAP) MRI datasets warped using a diffeomorphic tensor-based registration algorithm. By measuring propagators from co-registered MAP datasets with the same MAP basis functions we can directly quantify voxel-wise differences using angular dissimilarity metrics. We show examples from a cohort of healthy volunteers, and from a longitudinal clinical dataset of a patient undergoing carotid endarterectomy. This approach could provide improved sensitivity in the detection and characterization of subtle microstructural tissue changes in cross-sectional group and longitudinal single-subject clinical studies. |
| 3471 | Computer 135
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Diffusion kurtosis imaging–derived histogram metrics for prediction of KRAS/NRAS/BRAF mutations in rectal adenocarcinoma: Preliminary findings |
1Shanxi Province Cancer Hospital, Taiyuan, China, 2MR Clinical Sciences, Philips Healthcare Greater China, Beijing, China |
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It was revealed that DKI metrics with whole-tumor volume histogram analysis, especially the K75th parameter, yielded more preferable AUC and specificity values for predicting KRAS/NRAS/BRAF mutations than ADC and D values, and thus may potentially serve as an optimal imaging biomarker for the prediction of KRAS/NRAS/BRAF mutations for guiding targeted therapy. |
| 3472 | Computer 136
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Differential diagnosis of pathologic grade of hepatocellular carcinoma (HCC) using whole-tumor histogram and texture analysis based on apparent diffusion coefficient (ADC) map |
1The First Affiliated Hospital of Dalian Medical University, Dalian, China |
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This work aimed for ADC histogram and texture features based strategy to identify poorly differentiated hepatocellular carcinoma (HCC) which may own a high risk of recurrence or metastasis. The results showed that ADC histogram and texture features can discriminate HCC grade. The 95th percentile achieved the best result (AUC: 0.772; sensitivity: 90%; specificity: 72%) on ADC signal intensity map, forming a valuable strategy for clinical practice. |
| 3473 | Computer 137
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Diffusion tensor imaging of the sciatic and femoral nerves in osteoarthritis of the hip and osteonecrosis of the femoral head |
1Chiba University, Chiba, Japan, 2Shimoshizu Hospital, Yotsukaido, Japan |
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We visualizedsciatic and femoral nerves andcompared the fractional anisotropy (FA) values of the sciatic and femoral nerves in patients with osteoarthritis of the hip (OA) and osteonecrosis of the femoral head (ONFH) using diffusion tensor imaging (DTI). This study indicates thatthe FA values for the sciatic and femoral nerves in patients with OA and ONFH showed no significant differences with normal hips indicating no degeneration or demyelination occurred in either nerve. DTI may be able to differentiate hip diseases from lumbar nerve radiculopathy. |
| 3474 | Computer 138
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A Simplified Approach for Measuring Tissue ADC: Application to Prostate Diffusion Scans |
1Radiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden, 2Radiology, Brigham and Women's Hospital, Boston, MA, United States |
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A simplified approach is presented to obtain consistent tissue ADC data, irrespective of diffusion protocol, location within field of view and MR system. Examples of application in prostate diffusion scans are presented. This could greatly facilitate the establishment of suitable cut-off values to differentiate aggressive from indolent disease in prostate cancer, but as detailed in the abstract would entail several other substantial benefits that are universally applicable to diffusion imaging in tissues. |
| 3475 | Computer 139
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Optimization of b-values for estimation of IVIM D and f |
1Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden, 2Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden |
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IVIM parameter estimation restricted to D and f (avoiding D*) has gained increased popularity. In this study we propose a framework for optimization of b-value schemes for this application. We show that optimized b-values schemes contain exactly three unique b-value, regardless of the total number of acquisitions, and that parameter estimation uncertainty can be substantially reduced by the use of the optimized b-value schemes. |
| 3476 | Computer 140
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Whole-lesion histogram analysis of the apparent diffusion coefficient - a correlation study with histological grade of hepatocellular |
1Radiology, First Hospital of LanZhou University, lanzhou, China, 2First Hospital of LanZhou University, lanzhou, China, 3MR scientific marketing，Siemens healthineers，China, Lanzhou, China |
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Lately, an increasing number of studies made an effort to investigate the correlation between quantitative analysis of diffusion weighted imaging (DWI) and the histological grade of HCC. However, the optimal ADC parameter for characterization of grade of HCC has yet to be determined. Various investigators have evaluated that ADC value such as the mean ADC and minimum ADC correlate with histological grade of HCC, which were derived from single or several parts slice–based ROIs within tumors. We drew lesions on multiple slices to get more reliable estimate of lesion signal. |
| 3477 | Computer 141
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Microstructural Variations in Intra-axonal and Extra-axonal Spaces Associated with Punctate White Matter Lesions in Preterm Infants Reveal by White Matter Tract Integrity Metrics |
1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, 2MR Research China, GE Healthcare,Beijing,People's Republic of China, BengJing, China |
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Punctate white matter lesions (PWML) are common in preterm infants. Extensive microstructural changes were observed previously. However, specific changes related to axons and extra-axonal structures remain to be investigated. White matter tract integrity (WMTI) metrics derived from diffusion kurtosis imaging provide information of intra-axonal or extra-axonal spaces. This study aimed to use these metrics to quantify specific variations associated with PWML. Besides reduced fractional anisotropy and increased radial diffusivity, increased diffusivities in extra-axonal and intra-axonal spaces were found. Furthermore, tortuosity and fiber dispersion decreased obviously. These results suggested that PWML would influence axonal reorganization as well as extra-axonal structural integrity. |
| 3478 | Computer 142
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The Histogram Analysis of Intravoxel Incoherent Motion-Kurtosis (IVIM-Kurtosis) model for Detection of Prostate Cancer |
1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China |
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Diffusion-weighted (DW) MR imaging has a great potential in the study of prostate cancer (PCa). We aimed to assess the feasibility and efficacy of intravoxel incoherent motion-kurtosis (IVIM-Kurtosis) model for the differential diagnosis of PCa, benign prostatic hyperplasia and prostatitis (BPH/prostatitis). Thirty-six patients were enrolled and underwent MRI subsequently using in-bore transrectal MR-guided biopsy as the pathological reference. Significant differences were found for D and f values for the differential diagnosis of PCa and BPH/prostatitis, and D median and f median had the highest area under curve. The f, K and D* were correlated with Gleason score (GS) of PCa. |
| 3479 | Computer 143
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Diffusion Weighted Imaging with Apparent Diffusion Coefficient on the Assessment of Tumor Heterogeneity for the Differentiation of Molecular Subtypes in Breast Cancer |
1Memorial Sloan Kettering Cancer Center, new york, NY, United States |
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The study evaluated the utility of diffusion weighted imaging with apparent diffusion coefficient on the assessment of tumor heterogeneity for the differentiation of molecular subtypes in a population of 91 patients with invasive breast cancer. The authors investigated the use of histogram analysis and visual assessment of tumor heterogeneity for the differentiation of breast cancer subtypes derived via immunohistochemistry surrogates. The results obtained demonstrated that HER-2 enriched tumors had higher ADC values than other tumor subtypes. It was also demonstrated that histogram analysis and visual assessment of tumor heterogeneity could not reliably be used to differentiate tumor molecular subtypes. |
| 3480 | Computer 144
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Negative-Unlabeled Learning for Diffusion MRI |
1Department of Informatics, Technical University of Munich, Garching, Germany, 2CUBRIC, Cardiff University, Cardiff, United Kingdom, 3Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy, 4Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom |
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Machine learning strongly enhances diffusion MRI in terms of acquisition speed and quality of results. Different machine learning tasks are applicable in different situations: labels for training might be available only for healthy data or only for common but not rare diseases; training labels might be available voxel-wise, or only scan-wise. This leads to various tasks beyond supervised learning. Here we examine whether it is possible to perform accurate voxel-wise MS lesion detection if only scan-wise training labels are used. We use negative-unlabeled learning (an equivalent of positive-unlabeled learning) and achieve an AUC of 0.77. |
| 3481 | Computer 145
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Diagnostic Value of Apparent Diffusion Coefficient for predicting aggressive histological features of papillary thyroid carcinomas |
1Department of Radiology, Minhang Hospital, Fudan University, Shanghai, China |
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Objective: To investigate the value of preoperative diffusion-weighted magnetic resonance imaging for predicting aggressive histological features in papillary thyroid cancer (PTC). Methods: The mean, minimum apparent diffusion coefficient (ADCmean and ADCmin) and ADC value of the solid component (ADCsolid) were compared among different aggressive histological groups. Analyses of receiver-operating characteristic curve were also performed. Results: The ADC value in the low aggressive PTC were significantly higher than in high aggressive PTC. ADCmin values had the best performance. Conclusion: ADCmin values derived from DWI could be used as quantitative predictors of aggressive histological features in PTC. |
| 3482 | Computer 146
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DKI parameter inference by deep neural networks trained by synthetic data |
1Radiology, Hiroshima Heiwa Clinic, Hiroshima, Japan, 2Graduate School of Information Sciences, Hiroshima City University, Hiroshima, Japan |
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In general, DKI parameters (D and K) are obtained by fitting models to DWI signal values, such as by least-square fitting (LSF) methods. However, when DWI signal values are contaminated by noise of high level, fitting error is often observed especially for diffusional kurtosis K. In this study, we propose a robust method to infer DKI parameters based on deep neural networks trained by only synthetic data to overcome the limitations of real data training. Our experimental results including comparison with LSF showed the potential of our method for robust inference of DKI parameters. |
| 3483 | Computer 147
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Framework to Identify Motion-Related Artifacts in Non-Diffusion Weighted Reference Images |
1Waisman Center, University of Wisconsin Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin Madison, Madison, WI, United States |
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Motion related artifacts can significantly degrade the quality of quantitative measures estimated from diffusion weighted images. Here, we present a method to identify images with significant motion artifact by inspecting the high and low frequency domain from a 1-D Fourier transform along the phase-encode direction of the data. Our results demonstrate the feasibility of such an approach for identifying images with significant motion artifacts, which can ultimately be used to improve the quality of diffusion parameter estimates. This framework may provide a more objective approach to identify images affected by motion-artifact compared to traditional visual inspection. |
| 3484 | Computer 148
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Machine learning can boost the acquisition and estimation of anomalous diffusion model |
1Center for MRI Research, Peking University, Beijing, China, 2MR Research China, GE Healthcare, Beijing, China |
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The departure from mono-exponential decay of the diffusion-induced signal loss has promoted the research of anomalous diffusion in MRI. It has been found that anomalous diffusion models offer substantial advantages over the conventional method in clinical applications. However, these models require more diffusion weightings for complicated estimation procedure, which prevents its further application. In this study, we demonstrated that machine learning can be applied to accelerate the estimation of anomalous diffusion parameters. Furthermore, feature selection was used to identify the most relevant signals, thus helping to reduce the extensive sets of diffusion weightings. |
| 3485 | Computer 149
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Multi-parametric segmentation of whole-brain variability maps of diffusion MRI metrics |
1Neuroimaging, King's College London, London, United Kingdom, 2Forensic and Neurodevelopmental Sciences, King's College London, London, United Kingdom, 3Natbrainlab, London, United Kingdom |
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The analysis of the whole-brain statistical variability maps corresponding to different statistical coefficients provides quantitative and anatomical information regarding the reproducibility, reliability or biological variability of diffusion MRI data. However, the separate analysis of each statistical map cannot reveal the emerging relationships that exist between these three properties of the data and their interactions across the brain anatomy. In this abstract, we present a new integrated multi-parametric segmentation approach for the combined visualisation and analysis of the reproducibility, reliability and biological variability maps using diffusion MRI data acquired from an older population. |
| 3486 | Computer 150
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Alteration of IVIM Parameters by Signal Variation of Multiple b-value DWI Measurement |
1Department of Medical Imaging, China Medical University Hsinchu Hospital, Hsinchu, Taiwan, taichung, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, taichung, Taiwan, 3Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan, Taiwan., tainan, Taiwan, 4Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, taipei, Taiwan |
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The purpose of this study is to explore the alterations of IVIM measurement among multiple b-value sets with different low b-value and high b-value numbers using EPDWI. EPDWI with 41 different b-values was performed. For simulating the situation in clinic, five sets of 16 b-value numbers were chose from the 41 b values. DWI data of 1000 pixels for each WM, GM and CSF were randomly chose to evaluate the error of IVIM parameters. Our study demonstrated the variation of DWI signal with multi-b-value, affect the evaluation of Df and f but does not affect Ds in pixel-wise IVIM analysis. |
| 3487 | Computer 151
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Optimal selection of diffusion-weighting gradient waveforms using compressed sensing and dictionary learning |
1Univ Rennes, CNRS, Inria, Inserm, IRISA - UMR 6074, VisAGeS - ERL U 1228, F-35000 Rennes, France, Rennes, France |
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Acquisition sequences in diffusion MRI rely on the use time-dependent magnetic field gradients. Each gradient waveform encodes a diffusion-weighted measure; a large number of such measurements are necessary for the in vivo reconstruction of microstructure parameters. We propose here a method to select only a subset of the measurements while being able to predict the unseen data using compressed sensing. We learn a dictionary using a training dataset generated with Monte-Carlo simulations; we then compare two different heuristics to select the measures to use for the prediction. We found that an undersampling strategy limiting the redundancy of the measures allows for a more accurate reconstruction when compared with random undersampling with similar sampling rate. |
| 3488 | Computer 152
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Reduced Eddy Current induced image distortions and Peripheral Nerve Stimulation based on the Optimal Diffusion-weighting Gradient Waveform Design (ODGD) formulation |
1Universidad de Valladolid, Valladolid, Spain, 2Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 3Radiology, University of Wisconsin-Madison, Madison, WI, United States, 4University of Wisconsin-Madison, Madison, WI, United States |
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Diffusion-Weighted MRI (DW-MRI) often suffers from signal attenuation due to long TE, motion-related artefacts, dephasing due to concomitant gradients (CGs), and image distortions due to eddy currents (ECs). Further, the application of rapidly switching gradients may cause peripheral nerve stimulation (PNS). These challenges hinder the progress, application and interpretability of DW-MRI. Therefore, based on the Optimized Diffusion-weighting Gradient waveforms Design (ODGD) formulation, in this work we design optimal (minimum TE) nth-order moment-nulling diffusion-weighting gradient waveforms with or without CG-nulling able to reduce EC induced distortions and PNS-effects. We assessed the feasibility of these waveforms in simulations and phantom experiments. |
| 3489 | Computer 153
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Silent Distortionless DWI |
1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States, 3GE Healthcare, Menlo Park, CA, United States, 4Pediatric Radiology, Lucile Packard Children’s Hospital, Stanford University, Stanford, CA, United States, 5Electrical Engineering and Computer Science, UC Berkeley, Berkeley, CA, United States |
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Standard clinical EPI based diffusion sequence has high acoustic noise, which is uncomfortable for patients. The images acquired by single-shot EPI also suffer from distortion in areas of large susceptibility variations. To overcome these two limitations, we have developed a silent and distortion-free DWI sequence using a driven equilibrium diffusion prepared multi-segmented Rotating Ultra-Fast Imaging Sequence (RUFIS) readout. The sequence was validated in phantom, volunteers, and patients. The results showed the proposed sequence provides similar diffusion contrast and ADC measurement compared to DW-EPI, with improved image quality and a sound level that approaches that of ambient noise. |
| 3490 | Computer 154
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The tuned trinity of b-tensors |
1Random Walk Imaging, Lund, Sweden, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark, 3Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, Lund, Sweden |
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Unprecedented microstructural details of heterogeneous materials such as tissue are non-invasively accessible by multidimensional diffusion encoding (MDE) MRI using varying shapes of b-tensors. MDE can probe multidimensional distributions of diffusion tensors in terms of their size, shape and orientation. For robust conclusions, time-dependent diffusion effects need to be considered in MDE. A convenient recipe for generating b-tensors of varying shape was implemented including a single adjustable tuning parameter. The resulting b-tensors can thus be tuned for sensitivity to time-dependent diffusion. |
| 3491 | Computer 155
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An accurate surface-to-volume ratio estimation by general diffusion gradient waveform |
1Laboratoire PMC, Ecole Polytechnique, Palaiseau, France, 2NORMENT, KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Oslo, Norway, 3Institute of Clinical Medicine, University of Oslo, Oslo, Norway |
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We generalize Mitra’s formula for estimating the surface-to-volume ratio of an anisotropic medium with any pore shapes by using arbitrary diffusion gradient waveforms. We show that the surface-to-volume ratio can be significantly misestimated using the original formula without taking into account the applied diffusion gradient profile. For an accurate estimation, we derive new “isotropy” criteria which ensure that the diffusion weighted sequence is insensitive to the mesoscopic anisotropy of the sample. As a result, we introduce a novel class of porous media characteristics which are useful for biomedical applications. |
| 3492 | Computer 156
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Optimized diffusion gradient waveforms for estimating surface-to-volume ratio of an anisotropic medium |
1Laboratoire PMC, Ecole Polytechnique, Palaiseau, France, 2NORMENT, KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Oslo, Norway, 3Institute of Clinical Medicine, University of Oslo, Oslo, Norway |
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We present here a simple and efficient algorithm for designing of diffusion gradient profiles allowing one to implement prescribed theoretical properties. This algorithm generalizes the well-known sine and cosine decomposition and can handle various experimental constraints. Relying on recent diffusion MRI theoretical advances, we apply it to the challenging problem of estimating the surface-to-volume ratios in anisotropic media. |
| 3493 | Computer 157
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Oscillating Gradient Spin-Echo Diffusion Tensor Imaging of the Human Brain using FLAIR |
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, 2Siemens Healthcare GmbH, Erlangen, Germany |
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Oscillating-gradient spin-echo (OGSE) diffusion tensor MRI permits very short diffusion times (e.g. 5 ms) relative to the typical pulsed-gradient spin-echo (PGSE), but it is challenging to acquire in the human brain. Given low b-values and spatial resolution, it is more prone to problematic artifacts such as Gibbs ringing and partial-volume effects that can compromise diffusion parameter measurements. It is shown here that the use of inversion-recovery FLAIR to suppress cerebrospinal fluid can significantly reduce such artifacts, improve overall image/map quality, and provide better quantitation of OGSE-PGSE diffusion parameter differences in the white matter of the human brain. |
| 3494 | Computer 158
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Impact of different b-value combinations on Radiomics Features of Apparent Diffusion Coefficient in Cervical Cancer |
1Department of Radiology, Hubei Cancer Hospital, Wuhan, China, 2Medical engineering and technology center, Taishan Medical University, Taian, China, 3Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, United States |
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There is potential influence of different b-value combinations on evaluation of ADC-based radiomics features. The aim of this study is to investigate the difference between ADC-based radiomics feature extracted from ADC maps with different b-value combinations in cervical cancer. It was found that variable b-value combinations can play substantially impact on radiomics features extracted from corresponding ADC maps in cervical cancer. Therefore, we should pay more attention to the choice of b-value combinations in retrospective and multi-center studies. |
| 3495 | Computer 159
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A Real-time Solver for Convex Optimization of Diffusion Encoding Gradient Waveforms |
1Radiology, Stanford University, Stanford, CA, United States |
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Recent work has demonstrated the usefulness of designing time optimal gradient waveforms for diffusion encoding, especially when incorporating gradient moment nulling to mitigate bulk motion artifacts. Prolonged optimization times, however, can limit the usability of these methods. This work presents a solver fast enough to run in real-time, and investigates the performance over a range of parameters and tests for convergence. The solver is able to generate diffusion encoding gradient waveforms with gradient moment nulling in 5-50 ms – fast enough to permit real-time optimization on the scanner. |
| 3496 | Computer 160
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Impact of Residual Gradient Moments on Diffusion Weighted Imaging |
1Radiological Sciences Lab, Department of Radiology, Stanford University, Stanford, CA, United States |
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Bulk motion corrupts diffusion measurements in the heart but can be mitigated by nulling first and second gradient moments. When using optimization methods to design diffusion gradient waveforms with moment nulling, imperfect gradient waveforms arise from discrete convergence criteria, which impart residual (non-zero) gradient moments. This leads to intravoxel dephasing, signal loss, and inaccurate ADC measurements. Herein, simulations show that residual M0≤10-2mT/m•s, M1≤10-4mT/m•s2, and M2≤10-5mT/m•s3 leads to ≤5% increase in ADC. This work defines convergence criteria requirements for residual gradient moments that enable faster optimizations and more accurate measurements of ADC when using optimization methods for cardiac DWI sequence design. |
| 3497 | Computer 161
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In-vivo cardiac DTI: Comparison between Motion Compensated Optimized Diffusion Encoding (MODE) and Convex Optimized Diffusion Encoding (CODE) Techniques |
1Radiology, Ohio State University Wexner Medical Center, Columbus, OH, United States, 2Center for Biostatistics, Ohio State University Wexner Medical Center, Columbus, OH, United States |
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Diffusion-weighted imaging(DWI) is used to determine defective areas such as fibrosis in the myocardium without the need of contrast agent by calculating apparent diffusion coefficient(ADC) and fractional anisotropy(FA). However, DWI of heart is very challenging due to bulk motion to which diffusion encoding gradients are sensitive. Previous studies proposed CODE (convex optimized diffusion encoding) and MODE (Motion-compensated Optimized Diffusion Encoding). Aim of this study is to compare ADC and FA using MODE and CODE technique in healthy subjects. No significant difference was found between two techniques. However, for a given TE, MODE generated slightly higher b-value compared to CODE. |
| 3498 | Computer 162
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Using symmetrized temporal gradient profiles for water diffusion pore imaging on a 14.1 T spectrometer |
1Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Institute of Radiology, University Hospital Erlangen (FAU), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 4Molecular Structure Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany |
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Diffusion pore imaging can be used to retrieve the pore-space function of an arbitrary closed pore. While a few publications involving pore imaging using the long–narrow gradient approach exist [1–3], all of them involve the use of sophisticated acquisition schemes like CPMG or involve an additional readout gradient. In this study, we were able to show that it is indeed possible to acquire the pore space function of capillaries with a diameter of 15 µm using a simple modification of the long–narrow gradient scheme on a 14.1 T NMR spectrometer. |
| 3499 | Computer 163
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A novel approach to diffusion phase imaging using non-linear gradients in anisotropic media |
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, 2Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, United States, 3Philips Healthcare UK, Guildford, Surrey, United Kingdom |
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Classical methods for Diffusion-Weighted MRI use linear gradients to obtain information about tissue microstructure encoded in the loss of MR magnitude. These linear gradients cause diffusing spins to dephase which prevents the use of phase information. When, however, gradient fields are applied that vary quadratically in space, diffusion in anisotropic media results in a shift of net phase with only a minimal loss in signal magnitude enabling the exploration of MR phase. Both the theory of this new concept and Monte-Carlo simulations predict net phase for diffusion experiments using quadratic gradients in anisotropic media in excellent agreement. |
| 3500 | Computer 164
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Optimizing Diffusion MRI for Mapping Cortical Fiber Patterns |
1Stanford University, Stanford, CA, United States |
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A custom DW pulse sequence is optimized to minimize echo time and evaluate optimal trade-offs between SNR, b-value and spatial resolution for mapping cortical fiber patterns. Using a lower b-value (500 vs. 1000 s/mm2) failed to improve estimates of the principal fiber orientation in the cortex despite the significant boost in signal. Accurate estimates of the principal fiber orientation in the cortex requires a spatial resolution of 1.44 mm isotropic or less. |
| 3501 | Computer 165
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Motion-Robust and Distortion-Corrected Diffusion MR Imaging of the Liver with Optimized Motion-Compensated Waveforms and Multi-shot EPI acquisition |
1Medical Physics, University of Wisconsin Madison, madison, WI, United States, 2Radiology, University of Wisconsin Madison, madison, WI, United States, 3Applications and Workflow, GE Healthcare, Boston, MA, United States |
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Conventional liver diffusion MRI acquisitions suffer from several challenges including low spatial resolution, B0-induced distortions, and elastic motion-induced signal voids. In this work, motion-robust and distortion-corrected liver diffusion-weighted imaging (DWI) was enabled by combining optimized motion compensated diffusion waveforms with multi-shot EPI acquisitions. Diffusion-weighted images of healthy volunteers were acquired to evaluate the effect of motion compensation and distortion correction. Preliminary results demonstrate the feasibility of the proposed approach, including reduced ADC bias in the left lobe (due to the motion-robust waveforms) and reduced distortion (due to the multi-shot acquisition) compared to conventional liver DWI. |
| 3502 | Computer 166
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Towards clinically viable and robust measurement of microscopic diffusion anisotropy |
1Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada, 2Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ON, Canada |
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In contrast to fractional anisotropy, microscopic diffusion anisotropy allows measurement of pore structural anisotropy with no influence from orientational coherence. However, acquisitions that allow in vivo measurement of microscopic anisotropy are generally time-consuming and/or low SNR. Here, we introduce an efficient approach to perform isotropic diffusion encoding and measure high quality full-brain microscopic anisotropy in a scan time of only 3 minutes at 7T. Results are demonstrated in a healthy subject and MS patient, where clear delineation of lesions is observed in the latter case. |
| 3503 | Computer 167
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Reducing spectral anisotropy in isotropic b-tensor multidimensional diffusion encoding |
1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2Clinical Sciences, Department of Radiology, Lund University, Lund, Denmark, 3Brigham and Women’s Hospital, Boston, MA, United States, 4Harvard Medical School, Boston, Denmark, 5Department of Radiology, Lund University, Lund, Denmark, 6Harvard Medical School, Boston, MA, United States, 7Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, 8Random Walk Imaging AB, Lund, Sweden |
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Multidimensional diffusion encoding isotropic b-tensors eliminate rotational variance from anisotropic Gaussian diffusion, an essential feature for estimating microscopic anisotropy. In anisotropic substrates which exhibit non-Gaussian diffusion on the time scale of the encoding pulse, the variance in temporal characteristics of diffusion encoding across different directions – spectral anisotropy (SA) - may introduce a directional variance in apparent diffusivities. We propose an alternative isotropic encoding with drastically lower SA, which in turn allows accessing intrinsic signatures of non-Gaussian diffusion. |
| 3504 | Computer 168
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Diffusion MRI of the Brain with a Gradient Strength of 100 mT/m and a Slew Rate of 1200 T/m/s |
1Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland |
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The performance of diffusion-weighted single-shot EPI is limited by off-resonance artifacts and low signal-to-noise. To address both problems, we employ a recently developed gradient insert (strength: 100 mT/m, slew rate: 1200 T/m/s). Thereby the time for the diffusion encoding as well as the EPI readout train duration can be significantly shortened, resulting in higher signal yield and robustness against off-resonance artifacts. First in-vivo results are presented. |
| 3505 | Computer 169
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3D distortion-free multi-slab diffusion-prepared magnitude-stabilized bSSFP imaging |
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Physics and Biology in Medicine IDP, University of California, Los Angeles, Los Angeles, CA, United States, 3Biomedical Engineering, Tsinghua University, Beijing, China, 4Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States |
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A 3D diffusion-prepared magnitude-stabilized bSSFP (DP-MS-bSSFP) sequence was proposed and validated to achieve |
| 3506 | Computer 170
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In-vivo Diffusion Exchange Spectroscopy (DEXSY), to measure water exchange in tumours. |
1Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, United Kingdom, 2Microstructure Imaging Group, Centre for Medical Image Computing, Department of Computer Science, UCL, London, United Kingdom, 3The Francis CRICK institute, London, United Kingdom |
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We describe the first use of Diffusion Exchange Spectroscopy (DEXSY) in-vivo, to measure water exchange in tumours. We present preliminary data suggesting that we can capture information about the micro-structure of tumors, with what appear to be intracellular, extracellular and perfusion peaks present in diffusion-diffusion exchange plots, acquired from subcutaneous tumor xenograft models, in-vivo using DEXSY. |
| 3507 | Computer 171
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Effects of Diffusion Gradient Waveforms on Time-dependent Kurtosis and Microstructural Properties |
1Biomedical Engineering, Zhejiang University, Hangzhou, China, 2Radiology, Johns Hopkins University School of Medicine, BALTIMORE, MD, United States, 3Radiology, New York University School of Medicine, New York, NY, United States |
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Diffusion-time (td) dependent diffusion MRI is a promising tool to probe tissue microstructure. Although different diffusion gradient waveforms (DGW) have been introduced to achieve short and long td’s, whether they have comparable sensitivity to microstructural changes remains to be investigated. Here, we examined the td-dependency of kurtosis measured using pulsed, bipolar, and oscillating gradients with different microstructural substrates. Simulations and in vivo experiments showed that the choice of DGW affects the characteristics of time-dependent kurtosis, and this effect varied with microstructural size and permeability. This knowledge is important for design of td-dependent diffusion MRI experiments. |
| 3508 | Computer 172
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The optimal b value study of endogenous water molecule diffusion imaging in the diagnosis of brain tumors |
1RenMin hospital of Wuhan University, Wuhan, China, 2Zhongnan Hospital of Wuhan University, Wuhan, China |
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In this study, thirty-six cases of meningioma were divided into benign and malignant meningioma. ADC values fitted by 11 b values and any pairs of two b values were used to distinguish between benign and malignant meningioma. We found that, the ADC values of benign, malignant, and all meningiomas showed a decreasing trend with the increase of b value, and the smaller the b value, the greater the decrease. when the b value was ≥ 200 s/mm2, any combinations of b values could discriminate between benign and malignant meningioma. The ADC values obtained by fitting b = 700 and b = 1000 s/mm2 had the highest AUC value. |
| 3509 | Computer 1
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Sub-Millimeter Isotropic DTI and fiber tractography of the human Spinal Cord in-vivo |
1Duke University Medical Center, Durham, NC, United States |
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The ability to characterize complex microstructures in the small cross-sectional area of the spinal cord through diffusion tensor imaging has traditionally been limited by the achievable spatial resolution in-vivo. Through ultra-high spatial resolution diffusion imaging, this study presents a technique for accurately delineating complex fiber pathways such as the corticospinal tracts. When imaged with sub-millimeter isotropic spatial resolutions, it is possible to characterize intricate details in the spinal cord such as the bifurcations and decussations of the corticospinal tracts. The improved delineation of neural pathways in the spinal cord could facilitate the placement of stimulation electrodes for movement disorder treatments. |
| 3510 | Computer 2
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Multi-Echo Segmented Diffusion-Weighted MRI for Ex-Vivo Whole-Brain Measurements with 300mT/m Gradients |
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany |
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We provide a novel method to increase SNR of segmented diffusion-weighted EPI acquisitions. Multiple gradient echoes were acquired after each diffusion-preparation and combined in an SNR-optimized way using weightings from quantitative T2* maps. The combination of diffusion-weighted echoes yielded an SNR-gain of 58% compared to single-echo dMRI data with an increase in the segmented readout duration by only 23.1 ms. The multi-echo diffusion MRI acquisition and combination were employed to acquire high-quality ex-vivo diffusion-weighted MRI data from a wild chimpanzee brain. |
| 3511 | Computer 3
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A Multi-Echo Stejskal-Tanner EPI Sequence for Rapid Measurements of T2 and Diffusion Tensor Correlations |
1Institute of Neuroscience and Medicine 4, Jülich Research Centre, Jülich, Germany, 2Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 3Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 4Department of Neurology, RWTH Aachen University, Aachen, Germany, 5Institute of Neuroscience and Medicine 11, Jülich Research Centre, Jülich, Germany, 6JARA - BRAIN - Translational Medicine, Aachen, Germany |
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Initial phantom and in vivo results of a multi-echo Stejskal-Tanner EPI sequence are presented demonstrating the feasibility of rapid measurements for diffusion tensor and T2 correlations. The diffusion and T2 maps are artefact-free and are found to be very similar to the ones derived from the conventional individual-echo methods. However, the data tend to display slightly overestimated diffusivities and T2, which need to be investigated further. Compared to the standard method, the proposed multi-echo sequence reduces the scan time by a factor of five, which is necessary to make multidimensional diffusion techniques feasible in clinical settings. |
| 3512 | Computer 4
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Effects of imperfect slice separation in simultaneous multi-slice for diffusion kurtosis imaging |
1Department of Neurosurgery, Medical College of Wisconsins, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States |
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Simultaneous multislice (SMS) technique accelerates MRI data acquisition. However, slice separation in reconstruction is imperfect. This results in residual leakage between the simultaneously excited slices. For diffusion MRI, repeated pairing of the same slices in the image series leads to repeated leakage of a consistent diffusion signal from the other slice. Studies of this effect on diffusion MRI is sparse. Here, we tested two different SMS acquisition and image reconstruction techniques and quantified resulting errors on all diffusion kurtosis (DKI) metrics in different ROIs. Large errors were observed with SMS compared to singleband acquisitions for all DTI and DKI metrics |
| 3513 | Computer 5
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Evaluation of Diffusion-Weighted Readout-Segmented EPI in Macaque Brain Imaging at 7T |
1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, College of Biomedical Engineering & Instrument Science, Zhejiang University, HangZhou, China, 2School of Medicine, Zhejiang University, Hangzhou, China, 3MR Collaboration Northeast Asia, Siemens Healthcare, Shanghai, China, 4Siemens Healthcare GmbH, Erlangen, Germany, 5Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States |
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Diffusion-weighted imaging (DWI) has been widely used in brain structure and connectivity investigations and other neuroscience applications. To implement an optimized protocol for high spatial resolution DW imaging at ultra-high field, we have conducted macaque brain imaging by using readout segmented echo planar imaging at 7T. Our results indicate that, the rsEPI has potential to achieve DWI with improved signal-to-noise ratio and with the intent of minimizing geometric distortion. |
| 3514 | Computer 6
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A model free, sparse acquisition approach (« Sindex ») to investigate brain tissue microstructure from diffusion MRI data in the human brain |
1NeuroSpin/Joliot, CEA-Saclay, Gif-sur-Yvette, France, 2System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan, 3Graduate School of Medicine, Human Brain Research Center, Kyoto University, Kyoto, Japan |
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Diffusion MRI provides noninvasively information of tissue microstructure. Current models allow to empirically analyze data or to provide more insightful information on the tissue features. However, those models require strong assumptions on the underlying tissues and the acquisition of large image data sets with different acquisition parameters. We have investigated a new, model free approach which enables classification of tissue types from the “proximity” or resemblance of their diffusion MRI signal profile at a sparse set of key b values (maximizing sensitivity to tissue microstructure) to a library of “signature” signal profiles (e.g. typical brain grey and white matter). |
| 3515 | Computer 7
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Maximising Repeatability: It’s Time to Reconsider the Sampling Scheme for IVIM |
1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway, 2Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway, 3Division of Radiotherapy & Imaging, Cancer Research UK Cancer Imaging Centre, London, United Kingdom, 4Clinic of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway |
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Diffusion-weighted imaging (DWI) has the potential to improve characterisation and detection of breast cancer. A variety of models are available to fit the relationship between MRI signal and b-value, but the repeatability of such models is often overlooked. In this study, we simulate repeated DWI scans and quantify the precision of IVIM parameters from segmented fitting for D and f; our findings suggest that repeatability of f is highly dependent on disproportionate noise at b=0, and repeatability for f and D can be maximised by redistribution of signal averages. Optimal acquisition strategies for varying values of inter-scan noise are reported. |
| 3516 | Computer 8
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TRACTOGRAPHY OF THE TRIGEMINAL NERVE OUTSIDE THE BRAIN |
1SBHSE, Arizona state university, Tempe, AZ, United States |
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Diffusion Tensor Imaging (DTI) tractography used for the visualization of cranial nerves has mostly focused on tracts inside the brain. This work focuses on tracking trigeminal nerve branches using DTI outside the brain. Trigeminal nerve efferents in the face can be stimulated using transdermal electrical neuromodulation. Locations of subcutaneous tracts of the ophthalmic and maxillary branches of the trigeminal nerve may assist with electrode placement in these studies. Here, we describe use of HARDI-derived DTI to determine locations of trigeminal nerve projections in the face. |
| 3517 | Computer 9
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Time-efficient high resolution diffusion weighted SSFP measurements at 14.1T |
1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany, 3Institute for clinical anatomy and cellanalysis, Department of Anatomy, University Hospital Tübingen, Tübingen, Germany |
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This study investigates the use of diffusion weighted SSFP imaging for high-resolution diffusivity measurements of post-mortem tissue, using two different models (Wu-Buxton and Freed) and draws a comparison to conventional DW SE-Measurements. A toolbox was developed to optimize SSFP imaging parameters for selected tissue regions which was then used successfully. We showed that the SSFP approach is highly valuable for time-efficient high-resolution post-mortem diffusion weighted imaging. |
| 3518 | Computer 10
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Feasibility of 129Xe MRI Morphometry Measurements with Acceleration Factors of 7 and 10 |
1Robarts Research Institute, London, ON, Canada, 2Department of Medical Biophysics, Western University, London, ON, Canada, 3Division of Respirology, Department of Medicine, Western University, London, ON, Canada |
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Hyperpolarized gas pulmonary MRI provides physiologically relevant biomarkers of obstructive lung disease including emphysema, bronchopulmonary dysplasia, congenital lobar emphysema and alpha-1 antitrypsin deficiency. Recently, a stretched-exponential-model combined with under-sampling in the imaging and diffusion direction was used for the generation of 3He static-ventilation, T2* and multiple b-value diffusion-weighted MRI-based ADC/morphometry maps. We hypothesize that the 3He method can be modified to provide whole lung 129Xe MRI-based emphysema biomarkers including static-ventilation, T2*/ADC/morphometry maps with high-spatial-image-resolution in a single breath-hold. Therefore, in this proof-of-concept evaluation, our objective was to demonstrate a feasibility of this approach in a small group of patients. |
| 3519 | Computer 11
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3D distortion-free diffusion imaging using an accelerated multi-shot diffusion-prepared sequence |
1Biomedical Engineering, King's College London, London, United Kingdom, 2Siemens Healthcare, Frimley, United Kingdom, 3Cancer Imaging, King's College London, London, United Kingdom |
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Current methods for cancer diffusion imaging employ 2D single-shot diffusion weighted echo planar imaging sequences, which are fast but have limited resolution and are prone to distortion artefacts. The purpose of this work is to achieve 3D high-resolution and distortion-free diffusion imaging suitable for cancer precision diagnostics and therapy planning. A multi-shot diffusion-prepared sequence with gradient echo readout, centric encoding, and accelerated variable density acquisition was developed and tested in healthy volunteer brains as an exemplar. A full set of 2.2-fold accelerated diffusion weighted images in three diffusion directions was acquired in 4:30 min producing quantitative 3D distortion-free ADC maps. |
| 3520 | Computer 12
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Diffusion-Weighted ZOOM-EPI with Simultaneous Multi-Slice Imaging |
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany |
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Zonal oblique multi-slice (ZOOM) EPI uses cross-sectional RF excitations to focus the measurement volume to a small, inner volume which allows to reduce the FOV without aliasing in the phase-encoding direction. Thus, geometric distortions are reduced and the spatial resolution of diffusion-weighted acquisitions can be increased as has been demonstrated for the optic nerve and spinal cord. In this study, ZOOM-EPI is combined with simultaneous multi-slice (SMS), the boundary condition to avoid unwanted signal contributions is determined, and the feasibility to shorten acquisitions times is demonstrated for diffusion-tensor imaging (DTI) of the human spinal cord. |
| 3521 | Computer 13
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Improvement of EPI-based DWI of the head/neck region using additional local shim coils at 3 Tesla |
1Department for Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany, 2Department for Diagnostic and Interventional Radiology, Univeristy Hospital Tuebingen, Tuebingen, Germany |
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Implementing additional local shim coils into the head and neck surface coil may enhance the performance of EPI-based diffusion weighted imaging of the head/neck region at 3 Tesla. Thus, we evaluated single shot echo planar DWI and standard T1-weighted gradient echo acquisition without and with the use of additional local shim coils. In addition, apparent diffusion coefficients were quantified in specific anatomical regions. Local shim coils improved the homogeneity of the static magnetic field, resulting in marked improvement of image quality, signal loss, distortion and fat saturation. ADC values did not significantly differ between the measured anatomical compartments. |
| 3522 | Computer 14
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A novel Multishell Acquisition with Increased b-Shells and Sparse ORientations (MAISSOR) |
1Physics, University of Florida, Gainesville, FL, United States, 2Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States |
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With improvements in MRI technology, more informative diffusion acquisitions can be obtained to improve tissue microstructure analysis. In this study, a Multi-shell Acquisition with Increased b-Shells and Sparse ORientations (MAISSOR) is proposed to optimize diffusion acquisition. The scheme improves diffusion signal decay fitting while simultaneously improving fiber orientation distribution1 (FOD) calculations as well as diffusivity metrics, such as those derived from diffusion tensor imaging2 (DTI). |
| 3523 | Computer 15
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A rapid PROPELLER technique for high resolution diffusion weighted imaging |
1Department of Neuroradiology, Barrow Neurological Institute, Phoenix, AZ, United States, 2Philips Healthcare, Gainesville, FL, United States |
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Diffusion weighted imaging is routinely used in the clinical settings. EPI is commonly used but suffers from severe geometric distortion. TSE/PROPELLER based DWI techniques are free of geometric distortion, but lead to long scan time and high SAR. In this project we propose a new SPLICE X-PROP technique to provide rapid high resolution DWI, by incorporating a SPLICE acquisition approach and a cross-blade GRASE readout into the PROPELLER technique. The improvement over conventional SPLICE PROPELLER technique is demonstrated with volunteer scans. |
| 3524 | Computer 16
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Investigating microscopic diffusion anisotropy in the human kidney using multidimensional diffusion encoding |
1Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 2Radiology, Brigham and Women’s Hospital, Boston, MA, United States, 3Harvard Medical School, Boston, MA, United States, 4Physical Chemistry, Lund University, Lund, Sweden, 5Random Walk Imaging AB, Lund, Sweden, 6Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology, Queen Square, London, United Kingdom, 7Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, United Kingdom |
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Diffusion tensor imaging (DTI) has been widely used to provide tissue microstructure measures such as fractional anisotropy (FA). Advances in diffusion acquisition methods (e.g. efficient spherical tensor encoding) have enabled more specific microstructural parameters to be derived, including microscopic fractional anisotropy (µFA). This work focused on extending our initial observation of µFA in the kidney through a detailed analysis of the linear and spherical diffusion encoding in healthy subjects, by comparing conventional FA to the µFA in human kidneys, and investigating the technical limitations of the current approach. |
| 3525 | Computer 17
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Diffusion weighted multi-spin echo sequence fuses T2-relaxometry and diffusometry |
1Center for Advanced Imaging Innovation and Research (CAI2R), NYU School of Medicine, New York, NY, United States, 2Center for Biomedical Imaging, Dept of Radiology, NYU School of Medicine, New York, NY, United States, 3Siemens Medical Solutions, New York, NY, United States |
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Combination of diffusion weighted MRI with orthogonal measures such as T$$$_2$$$-weighting has been proposed to overcome the fit degeneracy found in microstructure modeling of diffusion signals. However, the repetition of diffusion measurements at different TE leads to unacceptably long acquisition times, hindering clinical applicability of this approach. Here, we propose an accelerated acquisition using a multi spin echo diffusion and T$$$_2$$$-weighted sequence which samples each diffusion weighting at several TEs with a CPMG read-out train after the standard monopolar diffusion encoding spin echo. In the current configuration this speeds the acquisition up by a factor of 2.5x. |
| 3526 | Computer 18
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Sensitivity of 2D-Selective RF Excitations for Inner-Field-of-View Diffusion-Weighted Imaging to Field Inhomogeneities |
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany |
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Inner-field-of-view techniques based on 2D-selective RF (2DRF) excitations reduce geometric distortions of echo-planar imaging and improve diffusion-weighted imaging of the human spinal cord. A comparison of two common approaches revealed that a setup with the 2DRF excitation collinear to the image plane suffers from a reduced signal-to-noise ratio (SNR) for tall slice stacks. In this study, it is shown that the SNR loss is related to the larger sensitivity of the corresponding 2DRF excitation to frequency offsets caused by field inhomogeneities and is particularly pronounced for the large fields-of-excitation and 2DRF pulse durations needed for tall slice stacks. |
| 3527 | Computer 19
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A comparative study of single shot EPI, reduced field of view EPI, PROPELLER FSE based diffusion weighted imaging in the evaluation of normal thyroid gland |
1The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 2GE Healthcare China, Beijing, China |
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Thyroid gland diffusion images often suffer from high level of image distortion due to poor magnetic filed homogeneity. We evaluated the image quality and compared apparent diffusion coefficient (ADC) of healthy thyroid gland using EPI DWI, rFOV DWI and PROPELLER DWI images respectively. Our results indicated that the image quality of rFOV is better than that of EPI and PROPELLER DWI, while the image quality has no significant difference between EPI and PROPELLER DWI. Moreover, there was no significant difference in ADC value between EPI and rFOV DWI images, while the ADC value of PROPELLER EPI was significantly higher. |
| 3528 | Computer 20
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Diffusion-Weighted Imaging Of Upper Abdomen: A Comparative Study In Healthy Volunteers |
1Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 2GE Healthcare, China, Beijing, China |
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Nowadays，no standard scanning protocol or parameter for upper abdomen DWI is available. Due to tension, fear or poor tolerance, patients’ respiration may vary during the scan, leading to incorrect ADC measurement and missed diagnosis. In our study, we performed quantitative and qualitative analyses of images acquired via respiratory-triggered, breath-hold and free-breathing DWI at both 1.5T and 3T, to compare their image quality and the apparent diffusion coefficient (ADC) values of upper abdomen, then decide which is the best technique for upper abdomen DWI. |
| 3529 | Computer 21
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VASE-RESOLVE: Accelerated Readout Segmented Echo Planar Imaging with Compressed Sensing and Variable-Width Readout Segments |
1University of Erlangen-Nuremberg, Erlangen, Germany, 2Siemens Healthcare GmbH, Erlangen, Germany, 3University of Glasgow, Glasgow, United Kingdom |
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Readout-segmented echo-planar imaging (EPI) with 2D navigator correction, also known as RESOLVE, is an established method for performing high-resolution diffusion weighted imaging in clinical studies. However, the method requires long acquisition times compared to single-shot EPI. A reduction in acquisition time could be achieved with Compressed Sensing (CS), but sub-sampling of EPI-based sequences is problematic because of the phase evolution during the echo train. This work introduces a new CS sampling scheme for readout-segmented EPI that varies the readout-segment width as a function of sampling density and preserves the phase relationship between data points. |
| 3530 | Computer 22
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Golden-Angle Rotating Single-Shot Acquisition (GA-RoSA) for Simultaneous High-Resolution DTI and IVIM |
1Indiana University, School of Medicine, Indianapolis, IN, United States, 2Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, United States, 3Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 4Siemens Medical Solutions, Inc., Chicago, IL, United States |
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High-resolution DWI often relies on multi-shot acquisitions, which suffer from long acquisition time and motion-related phase variations. Although effort has been made to accelerate DWI acquisitions, acquiring b=0 images still requires multiple shots and multiple averages. In this work, in addition to accelerating DWI acquisitions, the proposed method (GA-RoSA) further rearranged the b=0 acquisitions to cover a range of lower b-values without increasing scan times, so that IVIM parameters can be obtained for free. With a golden-angle rotation scheme, GA-RoSA introduced sampling incoherence facilitating its combination with sparsity-based reconstruction approaches. We demonstrated its feasibility for simultaneous high-resolution DTI and IVIM. |
| 3531 | Computer 23
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Can unprecedented echo times in human diffusion weighted fMRI help reveal its biological underpinnings? |
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom |
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The brain versus vein dilemma in BOLD fMRI has spurred research towards more direct correlates of neuronal activation. Diffusion-weighted fMRI (dfMRI) emerged as a potential alternative 17 years ago. However, its signal origins and utility have been greatly debated. In this work, we combine ultra-high-gradients and spiral readout to characterize dfMRI contrast in humans in parameter spaces (TE, b-value, SNR and resolution) that have never been accessible before. Varying TE over a wide range while keeping the b-value fixed allowed us to detect significant hemodynamic contributions to dfMRI contrast at a b-value of 1200 s/mm2. |
| 3532 | Computer 24
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Novel HARDI-ZOOMit protocol detects changes in spinal cord microstructure in patients with asymptomatic non-myelopathic degenerative cervical spinal cord compression |
1Department of Neurology, Palacký University, Olomouc, Czech Republic, 2Department of Neurology, University Hospital Olomouc, Olomouc, Czech Republic, 3Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States, 4Department of Biomedical Engineering, University Hospital Olomouc, Olomouc, Czech Republic, 5Central European Institute of Technology, Masaryk University, Brno, Czech Republic, 6Department of Neurology, University Hospital Brno, Brno, Czech Republic, 7Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria, 8High Field MR Centre, Medical University of Vienna, Vienna, Austria, 9Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 10Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada |
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Detection of degenerative cervical spinal cord compression (DCSCC) at early stage that causes spinal cord (SC) microstructure disruption is limited when current imaging techniques are used. Early detection of damage to SC can predict symptomatic degenerative cervical myelopathy (DCM). We are presenting novel HARDI-ZOOMit protocol (High Angular Resolution Diffusion Imaging + syngo ZOOMit sequence), which is able to detect changes in microstructural diffusion MRI (dMRI) parameters (e.g. fractional anisotropy – FA, mean diffusivity – MD) in asymptomatic DCSCC. Results obtained with HARDI-ZOOMit protocol reveal higher sensitivity when compared to clinical RESOLVE (REadout Segmentation Of Long Variable Echo trains) protocol. |
| 3533 | Computer 25
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Clinical feasibility of multi-band diffusion tensor imaging (DTI) using simultaneous multi-slice acquisition for presurgical planning: Comparisons with standard DTI in patients with brain tumor |
1Radiology, MSKCC, New York, NY, United States, 2MSKCC, New York, NY, United States, 3Medical physics, MSKCC, New York, NY, United States |
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Standard diffusion tensor imaging (s-DTI) is currently utilized during presurgical planning to visualize white matter tracts despite its long scanning time. Multi-band DTI (mb-DTI) utilizes simultaneous multi-slice excitation, which greatly reduces scanning time and increases coverage. In this study, 42 patients with brain tumor were analyzed using mb-DTI and s-DTI in the arcuate fasciculus and corticospinal tract, two critical white matter tracts for language and motor function, respectively. When using mb-DTI, scanning time was reduced by 40% and the image quality and quantitative parameters were preserved. This study demonstrated the clinical feasibility and potential advantages of mb-DTI during presurgical planning |
| 3534
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Computer 26
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Comparison and Assessment of IVIM-MRI Methods Using a Capillary Flow Phantom |
1Department of Radiology, LMU University of Munich, Munich, Germany, 2Comprehensive Pneumology Center, German Center for Lung Research, Munich, Germany |
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In this study different intravoxel incoherent motion (IVIM) MRI methods were assessed and compared using phantom measurement. The phantom was constructed to mimic a capillary bed and allowed for the controlled application of fluid flow at varying rates. Advanced IVIM MRI methods beyond the biexponential pseudo-diffusion model were shown to be capable of accurately characterizing fluid flow inside a capillary network yielding intuitive parameters in a reproducible manner. |
| 3535 | Computer 27
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What are the consequences of ignoring non-Gaussian diffusion in models of convection-enhanced drug delivery to the human brain? |
1Medicine, Cardiff University, Cardiff, United Kingdom, 2Psychology, Cardiff University, Cardiff, United Kingdom, 3Huntington's Disease Centre, UCL, London, United Kingdom, 4Psychology, Australian Catholic University, Melbourne, Australia |
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Convection-enhanced drug delivery to the human brain is a promising method for treating neurodegenerative diseases and brain tumors. Accurate predictions of the drug concentration via computational fluid dynamics models are essential, and models not accounting for diffusion non-Gaussianity give predictions that are not in good enough agreement with experimental results. We use a fluid dynamics model recently presented in the literature, which accounts for diffusion non-Gaussianity, to calculate the differences with models that do not account for it, in data from pre-symptomatic Huntington’s disease patients and metastatic brain tumor patients. We make recommendations on the use of fluid dynamics models in the clinical setting. |
| 3536
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Computer 28
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MEDUSA: a GPU-based tool to create realistic phantoms of the brain white matter microstructure using tiny spheres. |
1UNIRS, CEA/Joliot/Neurospin, GIf-sur-Yvette, France, 2Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Germany, Juelich, Germany, 3UNATI, CEA/Joliot/Neurospin, GIf-sur-Yvette, France |
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This work proposes a novel Microstructure Environment Designer with Unified Sphere Atoms (MEDUSA) to construct realistic white matter cellular phantoms ensuring the absence of overlapping cells. It relies on a CUDA-based collision solver that enables to reach high values of packing density and angular dispersion, even in the case of multiple fiber populations. MEDUSA thus achieves the fast construction of biomimicking white matter phantoms with fully controlled geometrical properties, including axons, astrocytes and oligodendrocytes. |
| 3537
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Computer 29
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Axon diameter estimation in fixed human optic chiasm using diffusion weighted MR microscopy and microstructure-informed tractography |
1Department of Systems Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 3Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 4Neurocomputation and Neuroimaging Unit, Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany, 5Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany, 6Signal Processing Lab (LTS5), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 7Department of computer science, University of Verona, Verona, Italy |
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We estimated mean axon diameter of ipsilateral bundles in a fixed human optic chiasm sample using diffusion weighted MR microscopy and COMMIT framework. We computed that the resolution limit for axon diameters of our dMRI data is about 1.3 µm, indicating that our approach is sensitive to a larger range of axon diameter distribution (ADD) than in-vivo dMRI studies. We found a similar pattern in the estimated ADD using MRI as was reported by a histological analysis of macaque monkeys’ optic chiasm, indicating that the estimated ADD provides similar sensitivity to regional differences in microstructure properties as in ex-vivo histology. |
| 3538 | Computer 30
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An observational study on the diffusion time and field strength dependency of the diffusion coefficient in human white matter |
1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 3Department Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 5Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 6Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany |
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Signal dependence on diffusion time has been reported in various tissues and has been connected to cellular restrictions. It is conceivable, however, that it partly originates from relaxation weightings of different compartments. In this study, we investigate the diffusion time dependence of the diffusion tensor in brain tissue at 1.5 T, 3 T and 7 T using a stimulated echo sequence. The results show clear time dependencies of axial and radial diffusivity. 7 T data show a reduction of both diffusivities, indicating a non-negligible role of compartmental relaxation weighting effects. |
| 3539 | Computer 31
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A microstructure fingerprinting approach with heterogeneous axon diameters: validation on feline spinal cord |
1ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, Belgium, 2Signal Processing Lab (LTS5), Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland, 3Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States, 4Centre hospitalier universitaire vaudois (CHUV), University of Lausanne (UNIL), Lausanne, Switzerland |
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A microstructure fingerprinting approach is proposed in which an optimal single-fascicle configuration is selected from a pre-computed collection of Monte Carlo diffusion signals, or fingerprints, uniquely relating the diffusion MRI signals to the underlying axon properties. The simulated 3D geometries feature randomly-placed cylinders with diameter heterogeneity. The approach is validated on a public dataset of ex vivo cat spinal cord and exhibits indices of axon density and of the mean and standard deviation of the axon diameter distribution in agreement with histological measurements. The method is shown to outperform AMICO, which relies on approximate analytical expressions for the signal, and a simpler model using Monte Carlo simulations in a homogeneous packing of identical cylinders. |
| 3540 | Computer 32
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A Diffusion MRI Approach to Tumour Microstructure Modeling with Two Cell Populations of Different Sizes |
1Medical Physics Unit and Department of Physics, McGill University, Montreal, QC, Canada, 2Research Institute of McGill University Health Center, Montreal, QC, Canada |
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Advanced diffusion-weighted MRI allows the characterization of cancer tumours noninvasively by estimating cell radius R and volume fraction vin. Existing methods map the apparent R and vin , under the assumption that a given voxel contains one cell population. This work investigates the feasibility of estimating the radii and volume fractions of 2 cell populations co-existing in the same voxel. This method could be useful in studying biphasic tumours like round cell/myxoid liposarcoma, which consist of high-grade and low-grade tumour cells, where the percentage of high-grade cells is strongly related to the risk of metastasis and changes the course of treatment. |
| 3541 | Computer 33
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HOTmix: characterizing hindered diffusion using a mixture of generalized higher order tensors |
1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Center for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Radiology, University Hospital Center, Lausanne, Switzerland, 4ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, Belgium, 5Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland, 6Department of Computer Science, University of Verona, Verona, Italy, 7Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark |
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We present HOTmix, a new model to describe the diffusion MRI signal for molecules undergoing hindered diffusion. HOTmix is based on a mixture of generalized higher order tensors, explicitly incorporating the diffusion sequence’s time-dependent parameters. The method was evaluated on simulated diffusion MRI signals obtained through Monte Carlo simulations, using intermediate diffusion times, mimicking both ex-vivo and in-vivo conditions. HOTmix provided better reconstructions compared to the standard diffusion tensor, the kurtosis tensor, and a single generalized higher order tensor. In future work, we will explore whether modelling the hindered compartment using HOTmix improves microstructural features estimated using dMRI. |
| 3542 | Computer 34
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Double diffusion encoding enables unique parameter estimation of the Standard Model in diffusion MRI |
1Centre for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom, 2Leeds Institute for Cardiac and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, United Kingdom, 3Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 4Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, 5Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom, 6School of Psychology, Australian Catholic University, Melbourne, Australia |
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The widely adopted Standard Model (SM) for diffusion in white matter tissue has been shown to possess intrinsic degeneracies, making parameter estimation from single diffusion encoding (SDE) data ill-conditioned. We extend the SM to a multidimensional diffusion MRI acquisition and analyse the case where the fibre orientation distribution function (fODF) is a Watson distribution. The information contained in the kurtosis tensor, accessed by SDE, is insufficient to recover biophysical model parameters from the MR signal. We prove that Double Diffusion Encoding (DDE), letting us additionally access the full diffusion tensor covariance, makes parameter estimation well-posed. |
| 3543 | Computer 35
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Estimation of Axon Conduction Delay, Conduction Speed, and Diameter from Information Flow using Diffusion MRI and MEG |
1Athena Project-Team, Inria, Université Côte d'Azur, Sophia Antipolis - Méditerranée, France |
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Information transmission delays in the brain are generated by the physical properties of axons, including their length and diameter. These delays have a range of a few milliseconds and can thus be observed in bioelectric recordings such as electroencephalography and magnetoencephalography (MEG). In this work, we present a novel algorithm to estimate axon diameters from diffusion MRI and MEG. This approach identifies information flow between cortical regions using a model where transmission delays are parameters. The delays which maximize information transfer are identified and, using streamline length obtained through tractography, are then converted to axon diameters. We present results obtained on four subjects of the Human Connectome Project. |
| 3544 | Computer 36
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What perivascular spaces do to diffusion MRI? |
1Medical Physics, University Medical Centre Freiburg, Freiburg, Germany, 2Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany, 3Faculty of Biology, University of Freiburg, Freiburg, Germany, 4University Medical Centre Freiburg, Freiburg, Germany |
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PVS is gaining importance in a many research fields. In using both in vivo and formalin fixed ex vivo methods, we sought to better understand what parameters in dMRI may be used to understood be as PVS in brain tissue. |
| 3545 | Computer 37
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Surface-to-Volume ratio mapping using Oscillating Gradient Diffusion (OGSE) Spectroscopy for cancer characterization in the ex-vivo prostate |
1The University of New South Wales, Sydney, Australia, 2The University of Sydney, Sydney, Australia, 3Royal Prince Alfred Hospital, Sydney, Australia |
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This study investigates mapping of Surface-to-Volume (S/V) ratios from short diffusion time derived ADC maps to detect and characterize prostate cancer. ADC was mapped using a cos-OGSE DWI (fosc=50-200Hz) in one unfixed prostate (Gleason 4+4). Using a previously established model, S/V and free cytosol diffusivity (D0) maps were estimated by fitting the temporal behaviour of ADC. S/V and D0 were able to clearly and significantly separate the cancer and normal peripheral zone as indicated by a t-test and ROC curves. The geometrical nature of S/V may provide additional information to better characterize prostate cancer independent from diffusion related parameters. |
| 3546 | Computer 38
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Diffusion Time Dependence in Crossing Fiber Area in in vivo Human White Matter |
1Radiology, Juntendo University School of Medicine, Tokyo, Japan, 2Radiology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan, 3Radiology, National Institute of Radiological Sciences, Chiba, Japan, 4Siemens Japan K.K, Tokyo, Japan, 5Siemens Healthcare GmbH, Erlangen, Germany |
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We investigated the diffusion time dependency of diffusion metrics in the white matter crossing fiber areas with different diffusion times using OGSE, PGSE and STEAM-DTI in in vivo human white matter at 3T. Our results show that ADC and AD decreased with increasing diffusion time at Δless than 100ms; after that ADC increased with increasing diffusion time. RD decreased and FA increased with increasing diffusion time. Moreover, the changes of white matter fODF in the white matter crossing fiber area at different diffusion times are shown. |
| 3547 | Computer 39
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Random walk simulation of diffusion MRI in geometries constructed from two-photon microscopy of cortical gray matter |
1Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands |
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| 3548 | Computer 40
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Probing tissue microstructure using filtered q-trajectory imaging |
1Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital, Boston, MA, United States, 3Lund University, Lund, Sweden |
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We introduce an approach to characterize tissue microstructure using an extension of the q-trajectory imaging (QTI) technique in diffusion MRI. Our approach applies multiplicative filters to the diffusion tensor distribution (DTD) functions of the underlying tissue to obtain more specific information of tissue microstructure using the statistical moments of the filtered DTD's.We propose several descriptive statistics to distinguish microstructures that cannot be separated using existing methods.These measures are demonstrated in simulations and in vivo data acquired from a human brain. |
| 3549 | Computer 41
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Time Dependence in B-Tensor Encoding |
1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Great Ormond Street Institute of Child Health, University College London, London, United Kingdom |
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B-tensor encoding is becoming increasingly popular in microstructural imaging. In this technique microscopic tissue features are estimated by using different gradient waveforms that typically have different time regimes. This work studies for the first time two potential time-dependence issues that arise from these methods in-vivo in the human brain. We detect time-dependence effects in both cases, and even though these are small on a clinical system, they should not be overlooked. |
| 3550 | Computer 42
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Comparing Fiber Orientation Estimates from CLARITY and Diffusion MRI in Macaque Visual Cortex |
1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Department of Radiology, Stanford University, Stanford, CA, United States, 3CNC Program, Stanford University, Stanford, CA, United States, 4Department of Electrical Engineering, Stanford University, Stanford, CA, United States, 5Department of Computer Science, University of Verona, Verona, Italy, 6Radiology Department, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland, 7Department of Bioengineering, Stanford University, Stanford, CA, United States, 8Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States, 9Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States |
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Tissue clearing techniques offer new possibilities for reconstructing precise 3D axons trajectories. Here, we cleared a 1.5cmx1.3cmx0.3cm cuboid of rhesus macaque visual cortex using CLARITY 3D histology with a neurofilament stain to highlight axonal projections and compared the CLARITY-based fiber orientation estimate to a diffusion tensor MRI atlas. We found better agreement in grey matter than in white matter, potentially reflecting difficulties estimating the structure tensor in highly saturated regions of the CLARITY sample. This work demonstrates one of the largest and highest quality CLARITY cuboids from a macaque brain and explores key steps in the co-registration and analysis required to make a robust comparison against DTI data. |
| 3551 | Computer 43
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Microstructural Parameter Estimation of Skeletal Muscle Using Random Forest Model of dMRI |
1Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Beckman Institute for Advanced Science and Technology, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 4Radiology, Carle Foundation Hospital, Urbana, IL, United States |
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Results are presented for a random forest model to estimate skeletal muscle microstructure parameters from |
| 3552 | Computer 44
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Reliability of microstructural quantification with diffusion MRI in brain tumors. |
1Padova Neuroscience Center, University of Padova, Padova, Italy, 2Department of Information Engineering, University of Padova, Padova, Italy, 3Department of Neuroscience, University of Padova, Padova, Italy |
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Most existing biophysical models used to quantify diffusion microstructural information are designed for the healthy brain. When pathological processes occur, the diffusion signal of cancerous regions is altered, possibly biasing the fitting results of these models and making their parameter estimates unreliable. In this work, we investigate the precision and accuracy of estimates provided by several well known diffusion models, by evaluating their goodness-of-fit with residual sum of squares map and the parameter reliability with the bootstrap technique. |
| 3553 | Computer 45
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Diffusion Kurtosis Imaging (DKI) Biomarkers correlate with dysfunction in the EAE model of MS |
1CFIN, Aarhus University, Aarhus, Denmark, 2Department of Neurobiology Research, Institute for Molecular Medicine,University of South Denmark, Odense, Denmark, 3Champalimaud Center for Unknown, Lisbon, Portugal, 4Dept. of Physics and Astronomy, Aarhus University, Aarhus, Denmark |
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To study the relationship between microstructure and disability, 18 ex-vivo spinal cords from a mouse model of MS (EAE) were investigated using DKI and a biophysical model of diffusion. Diffusion data were acquired together with T2* images to delineate lesions. Kurtosis tensors and microstructural parameters were used for statistical analysis using a LME model. The results show a strong relation between disability and kurtosis tensor parameters similar to observations in other hypomyelinating MS models and in patients. Conversely, changes in model parameters, such as extra-axonal axial diffusivity, are clearly different from previous studies using other animal models of MS. |
| 3554 | Computer 46
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Effects of T2 relaxations on diffusion heterogeneity in the presence of tumor malignancy-related microstructural changes |
1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, United States, 2Department of Neurology, University of Kansas Medical Center, Kansas City, KS, United States, 3Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States |
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Cell compartments can present non-uniform T2 relaxations, depending on tissue properties. The non-uniform T2 relaxation has been shown to affect measurements of apparent diffusion coefficients (ADC). In additional to ADC, diffusion heterogeneity measured by modeling non-monoexponential decay has been used to characterize water diffusion in tissue microstructure. The purpose of this study is to study the effects of non-uniform T2 relaxations on the diffusion heterogeneity using a Monte Carlo simulation. The results demonstrate that the diffusion heterogeneity may provide more information about water diffusion within microstructure with non-uniform T2 relaxations. |
| 3555 | Computer 47
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Delineation of white matter microstructural maturation of infant brain with DKI |
1Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Radiology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States, 3Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States |
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Diffusion kurtosis imaging (DKI) based on multi-shell diffusion MRI may offer extra information on WM microstructural complexity changes during infant development compared to conventional DTI. After acquiring DKI and DTI from 18 normal infants aged 0-1 year, we measured the mean kurtosis (MK) and fractional anisotropy (FA) of all major WM tracts by combining WM skeletonization process and WM tract labels. Significant age-related increases in both MK and FA were found in all tracts. Distinctive developmental trajectories of WM tracts with MK measurements compared to those with FA measurements were revealed, indicating heterogeneous increases of microstructural complexity among WM tracts. |
| 3556 | Computer 48
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Time dependence and stability of diffusion tensor metrics in a hydrophilic, electrospun, water-perfused, hollow fiber phantom at 3T |
1Developmental Imaging and Biophysics, University College London, London, United Kingdom, 2Medical Radiation Physics, National Physical Laboratory, London, United Kingdom, 3University of Manchester, Manchester, United Kingdom, 4Neurology Applications Development, Siemens Healthcare GmbH, Erlangen, Germany |
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We assess the dependence of Diffusion Tensor Imaging metrics on diffusion time using a well-characterised hydrophilic phantom comprised of parallel hollow fibers with radii comparable to axons in healthy human white matter. |
| 3557 | Computer 49
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Experimental validation and SNR analysis of a clinical double diffusion encoding sequence |
1UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 2Champalimaud Neuroscience Programme, Lisbon, Portugal |
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Double diffusion encoding (DDE) allows the estimation of microscopic fractional anisotropy (μFA), which is a promising metric for studying microstructural properties of brain tissue independent of orientation dispersion. However, a large number of acquisitions is needed to obtain a rotationally invariant measurement of μFA, which poses a problem in clinical settings. A DDE protocol with a reduced number of acquisitions has recently been proposed as a solution. In this study, we assessed the accuracy of this approach and its potential for reporting μFA accurately. Our results show that a reduced number of acquisitions is sufficient for characterizing μFA. |
| 3558 | Computer 50
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Precision of microscopic fractional anisotropy estimation using double diffusion encoding |
1UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 2Champalimaud Neuroscience Programme, Lisbon, Portugal |
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Microscopic fractional anisotropy (μFA) estimation using diffusion MRI is a promising new method for quantifying microstructure, diagnosing pathologies, and measuring brain development. In order for μFA to be a useful metric in clinical and neuroscientific research, its robustness to noise has to be properly understood. In this study, precision of μFA estimation was quantified for different noise levels using propagation of error calculations, simulations, and imaging experiments. We show that μFA is non-linearly sensitive to noise, being the most instable at low values of mean diffusivity (MD) and μFA, and that increasing accuracy by correcting for higher order effects results in decreased precision. |
| 3559 | Computer 51
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Machine learning based estimation of axonal properties in the presence of beading |
1UNIRS, CEA/Joliot/Neurospin, GIf-sur-Yvette, France, 2Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Germany, Juelich, Germany, 3UNATI, CEA/Joliot/Neurospin, GIf-sur-Yvette, France |
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In this work, we investigate the potential of machine learning techniques to make one step forward by quantitatively estimating beading amplitude, a specific marker of pathological beading using frequency-dependent changes in diffusion measurements. Classification and regression are performed using Extremely Randomized Trees from OGSE signals corresponding to 6 distinct frequencies and synthesized from numerical simulations in realistic white matter phantoms depicting beaded axons. |
| 3560 | Computer 52
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Tensorial formulation allowing to verify or falsify the microstructural standard model from multidimensional diffusion MRI |
1Centre for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom, 2Leeds Institute for Cardiac and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, United Kingdom |
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The standard model (SM) has been proposed as an appropriate diffusion MRI microstructural model for brain white matter. Using the cumulant expansion up to 2nd order in the b-tensor, it has been recently shown that multidimensional diffusion encoding makes the model parameter estimation problem well-posed. However, the tensorial properties of the expansion and their relationship with the SM assumptions have not been exploited. We reformulate the solution of the SM in an elegant tensorial form and analyse the constraints the SM imposes, showing how they can potentially falsify the model. Some simulations show the test feasibility for high-quality signals ($$$\text{SNR}\geq 50$$$). |
| 3561 | Computer 53
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Permeable Barrier Modeling of Age Induced Changes in the Time Dependent Diffusion Eigenvalues |
1Physics, UC San Diego, San Diego, CA, United States, 2Radiology, UC San Diego, San Diego, CA, United States, 3Physics, San Diego State University, San Diego, CA, United States |
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The time dependence of the diffusion eigenvalues derived from diffusion tensor imaging allows one to probe tissue microstructure. A diffusion model is required to derive inferences about the microstructure from the time dependent eigenvalue data. We applied the Random Permeable Barrier Model1 to the time dependent diffusion data to infer age related changes in skeletal muscle microarchitecture. The tertiary eigenvalue at the largest diffusion time was significantly different between young and senior cohorts. Model derived myofiber size decreased and free diffusion coefficient increased with age, though neither parameter reached significance. |
| 3562 | Computer 54
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Estimating mixtures of 6D diffusion tensor distributions with "Magic DIAMOND": are b-plates better than b-spheres? |
1Université de Sherbrooke, Sherbrooke, QC, Canada, 2MR Clinical Science, Philips Healthcare Canada, Markham, ON, Canada, 3Dept. of Radiology, Boston Children’s Hospital, Boston, MA, United States |
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Tensor-valued diffusion encoding enables disentangling isotropic and anisotropic diffusion components. However, its impact on estimating brain microstructural features has only been studied in a handful of parametric models. In this work, we evaluate the Magic DIAMOND model, that allows characterization of crossing fascicles and assessment of diffusivities for each, using combinations of linear, planar and spherical encodings in vivo. Building statistics through stratified bootstrap, we show that spherical encoding substantially increases the variance in estimated parameters and should be avoided. Planar encoding, on the other hand, did not offer clear improvement or worsening within our current acquisition scheme and setup. |
| 3563 | Computer 55
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MicroLearn: Framework for machine learning, reconstruction, optimization and microstructure modeling |
1Intelligent Systems Engineering, Indiana University Bloomington, Bloomington, IN, United States, 2University Medical Center Freiburg, Freiburg, Germany, 3The University of Minnesota Twin Cities, Minneapolis, MN, United States, 4Cardiff University, Cardiff, United Kingdom, 5Psychological and Brain Sciences, Indiana University Bloomington, Bloomington, IN, United States, 6Databricks, San Francisco, CA, United States |
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MicroLearn is a Machine Learning and Model Fitting framework that enables modular construction of multi-compartment microstructure models in crossings with fast and accurate parameter estimation. |
| 3564 | Computer 56
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Investigating the Benefits of Incorporating Higher Order Spherical Harmonics in Axon Diameter Measurements |
1Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Separating out the scalar and orientation-dependent components of the diffusion MRI signal offers the possibility of increasing sensitivity to microscopic tissue features unconfounded by the fiber orientation. Recent approaches to estimating apparent axon diameter in white matter have employed spherical averaging to avoid the confounding effects of fiber crossings and dispersion at the expense of losing sensitivity to effective compartment size. Here, we investigate the feasibility and benefits of incorporating higher-order spherical harmonic (SH) components into a rotationally invariant axon diameter estimation framework and demonstrate improved precision of axon diameter estimation in the in vivo human brain. |
| 3565 | Computer 57
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On the feasibility of apparent exchange rate mapping in non-periodic systems with multiple cell sizes |
1Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Institute of Radiology, University Hospital Erlangen (FAU), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany |
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Apparent exchange rate (AXR) mapping might provide an insight into the exchange of water between intra- and extracellular space by using a double-diffusion encoded sequence with varying mixing times between the two gradient pairs. The connection between AXR and permeability has already been validated for simplified two-compartment models. However, multi-compartment systems and non-periodic geometries have not been evaluated so far. In this study, we were able to show that it is also possible to reliably connect permeabilities to AXR-values for these geometries. Furthermore, the AXR was only dependent on average cell size and not on the number of compartments. |
| 3566 | Computer 58
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Computational frameworks for multi-fascicle models: impact on microstructural descriptors |
1Computational Radiology Laboratory,Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States, 2Signal Processing Lab (LTS5), École polytechnique fédérale de Lausanne, Lausanne, Switzerland, 3University of Oxford, Oxford, United Kingdom |
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When performing operations on multi-fascicle DCI models, the need to preserve microstructural descriptors such as fFA and fMD is important. In this work we compared different multi-fascicle computational frameworks by assessing their impact on microstructure properties. Specifically, we investigated the impact after geometrical transformation and averaging of multi-fascicle models, two key operations when carrying out population studies. We found that Euclidean and log-Euclidean frameworks resulted in a decrease of fFA and fMD. More surprisingly, the values of microstructural descriptors depended on the number of subjects. The quaternion framework, in contrast, was the best at preserving microstructural features. |
| 3567 | Computer 59
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Non-parametric axon diameter distribution mapping with PGSE: reconstruction of uni- and multimodal distributions |
1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Center for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Computer Science, University of Verona, Verona, Italy, 4Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland, 5Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark |
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White matter diffusion MRI enables non-invasive estimation of the axon diameter distribution, which is of interest as it modulates communication speed and delays between brain regions, and changes during development and pathology. Distribution mapping is challenging: current methods simplify it by either estimating the mean diameter, imposing parametric distributions, or combining non-parametric approaches with Double Diffusion Encoding. We present a non-parametric framework based on a PGSE protocol. Simulations show robust reconstruction of unimodal and bimodal distributions. The method is sensitive to population specific changes within bimodal distributions, as long as the underlying populations are separated by a minimum distance. |
| 3568 | Computer 60
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Polynomial Meta-Model of Bloch-Torrey Equation for Track-based Regularization of Microstructural Inversion |
1Mechanical Science and Engineering, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States |
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A meta-model approach is presented which fits a multi-dimensional polynomial to numerical solutions of the Bloch-Torrey equation after being parameterized by microstructural and diffusion encoding parameters. This meta-model allows analytical representation of the solution space enabling analytical analysis of the space as well as |
| 3569 | Computer 61
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Improving Tractography in Baby Diffusion MRI via Asymmetric Spectrum Imaging |
1Department of Radiology and BRIC, University of North Carolina, Chapel Hill, Chapel Hill, NC, United States |
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Fiber tractography in baby diffusion MRI is challenging due to the low and spatially-varying diffusion anisotropy. In this abstract, we will introduce a method called asymmetric spectrum imaging (ASI) to improve estimation of white matter pathways in the baby brain by (1) incorporating an asymmetric fiber orientation model to help resolve subvoxel fiber configurations such as fanning and bending, and (2) explicitly modeling the spectrum of diffusion typical in the developing brain. |
| 3570 | Computer 62
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Diffusion of the perivascular space fluid is anisotropic in conventional DWI |
1Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 2Department of Psychology, University of Southern California, Los Angeles, CA, United States, 3Neuroscience graduate program, University of Southern California, Los Angeles, CA, United States, 4Department of Radiology, University of Southern California, Los Angeles, CA, United States, 5Department of Radiology, Alfred Health, Melbourne, Australia |
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Perivascular space (PVS), also known as Virchow-Robin space, is a pial-lined, fluid-filled structure that surrounds vessels in the cerebral cortex 1,2, and occupies a large portion of the cerebral tissue. PVS has an anisotropic morphology 3–5 and is mainly aligned with the white matter 6. However, its diffusion MRI profile has not been studied. Here we show experimental evidences that that PVS can be measured with diffusion MRI and the signature of this compartment is anisotropic. |
| 3571 | Computer 63
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Dependence of harmonic power on b-value for fiber ball imaging: comparison of theory and experiment |
1Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States, 3Department of Neurology, Medical University of South Carolina, Charleston, SC, United States |
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Fiber ball imaging (FBI) is a recently proposed diffusion MRI (dMRI) method for estimating fiber orientation density functions together with specific microstructural parameters in white matter. The theory underlying FBI predicts the b-value dependence for the dMRI harmonic power of any given degree as long as the b-value is sufficiently large. Good agreement between theory and experiment has been previously demonstrated for the zero-degree harmonic power. Here the predicted functional forms for higher degree harmonics are shown to also agree well with experimental measurements, providing additional support for the validity of FBI. |
| 3572 | Computer 64
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Diffusion time dependence in the mid-time regime: a simulation study using PGSE. |
1imec-Visionlab, Department of Physics, University of Antwerp, Antwerp, Belgium, 2Delft Center for Systems and Control, Delft University of Technology, Delft, Netherlands |
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The purpose of this work is to study the effect of varying the diffusion time on the estimation of the parameters of the two-compartment diffusion tensor model in the mid-time regime. Simulation results show that the precision of the diffusion time-dependent compartmental parameter estimates increases when a variable echo time acquisition scheme is used. At low SNR, however, including diffusion time-dependence may lead to a high bias and variance compared to the more conventional non diffusion time-dependent model. |
| 3573 | Computer 65
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Biases of microstructure models in baby diffusion MRI |
1Biomedical Engineering Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Department of Radiology and BRIC, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States |
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In this abstract, we show that some commonly used microstructure models do not perform as aspected when dealing with baby diffusion MRI, resulting in biased measurements. We found that this is mainly due to the greater water content in the developing brain. We show that the recently introduced Spherical Mean Spectrum Imaging (SMSI) [4] gives stable measurements in the presence of free water, making it well-suited for baby diffusion MRI. |
| 3574 | Computer 66
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MicroQIT - A Computational Framework for Population Microstructure Imaging |
1Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, Los Angeles, CA, United States |
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Microstructure imaging provides a quantitative tool for characterizing neural tissue with diffusion MRI and expanding our understanding of how the brain changes in health and disease. However, robust computational tools are needed for population imaging studies, so we developed a computational framework (MicroQIT) using the Quantitative Imaging Toolkit to meet this need by providing regional summaries and spatially normalized microstructure parameter maps. It supports a variety of ways to extract microstructure information from multi-shell diffusion MRI, leverages grid computing environments, and is available for use by the research community for future studies. |
| 3575 | Computer 67
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An in vivo investigation on quantitative metrics of diffusion kurtosis tensor: the effect of diffusion gradient parameters in the clinical setting |
1Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli County, Taiwan, 2Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany, 3Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan, 4Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Jülich, Germany, 5JARA - BRAIN - Translational Medicine, Aachen, Germany, 6Department of Neurology, RWTH Aachen University, Aachen, Germany, 7Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan |
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Diffusion kurtosis imaging (DKI) is an emerging technique that provides additional information to delineate tissue microstructures by quantifying the non-Gaussian water molecular diffusion. Although the capability of DKI has been demonstrated, the effects of diffusion gradient parameters on its quantitative metrics, particularly in the clinical setting, have not been fully understood yet. This study aims to investigate the effect of diffusion gradient parameters on diffusion kurtosis tensor calculation and its quantitative metrics. In vivo results show that diffusion gradient duration has incremental influence on DKI quantitative metrics in the clinical setting. Further investigation with more subjects would help to statistically solidify our findings. |
| 3576 | Computer 68
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Test-retest reliability of 3-tissue constrained spherical deconvolution of diffusion MRI data by analysis of three separate cohorts |
1Department of Radiology & Medical Imaging, Division of Neuroradiology, University of Virginia Health System, University of Virginia, Charlottesville, VA, United States, 2The Florey Department of Neuroscience, University of Melbourne, Melbourne, Australia, 3The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 4Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, United States |
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It has previously been demonstrated that, by using 3-tissue constrained spherical deconvolution, separate compartments encompassing cerebrospinal fluid-like, white matter-like, and grey matter-like, signal fractions can be derived from diffusion MRI data. This study explores the reliability of these compartments in three test-retest cohorts with a variety of timescales and scanning parameters. Whole-brain average signal fractions show excellent reliability across all datasets, particularly in determining the CSF-like signal fraction. This suggests that variations in whole brain signal fraction measurements are likely to be attributable to experimental manipulation or pathology and not variation introduced by performing the analysis. |
| 3577 | Computer 69
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Powering Up Microstructural Imaging: assessing cross-metric and cross-tract statistical power on an ultra-strong gradient MRI system |
1Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom, 2Department of Neuroimaging, King's College London, London, United Kingdom |
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We present cross-metric and cross-tract assessment of test-retest repeatability for microstructure measures on an ultra strong gradient MRI scanner (CONNECTOM 3T) in the human brain. We show that several MRI metrics of tissue microstructure are reliable and present relative sample sizes required to provide sufficient statistical power across different white matter pathways and microstructure metrics. |
| 3578 | Computer 70
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Improving reproducibility of diffusion connectome analysis using deep convolutional neural network model |
1Pediatrics and Translational Imaging Laboratory, Wayne State University School of Medicine, Detroit, MI, United States, 2Translational Neuroscience Program, Wayne State University School of Medicine, Detroit, MI, United States, 3Pediatrics, Neurology and Translational Imaging Laboratory, Wayne State University School of Medicine, Detroit, MI, United States |
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Reproducibility of diffusion-weighted structural connectomes is highly dependent on acquisition and tractography model, limiting the interpretation of connectomes acquired in the clinical setting. This study proposes a novel deep convolutional neural network (DCNN) to improve the reproducibility of structural connectomes, by which highly reproducible streamlines can be identified via an end-to-end deep learning of reference streamline coordinates in Human Connectome Project diffusion data. Preliminary results demonstrate that the proposed DCNN prediction model can improve the reproducibility of clinical connectomes (31.29% of F-statistics in intraclass correlation coefficient) and effectively remove noisy streamlines based on based on their poor prediction probabilities. |
| 3579 | Computer 71
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Resolving crossing fibers with the inclusion of intra-axonal diffusion modeling |
1Biomedical Engineering, Washington University in St. Louis, st louis, MO, United States, 2Radiology, Washington University School of Medicine, St. Louis, MO, United States, University City, MO, United States, 3Chemistry, Washington University in St. Louis, st louis, MO, United States, 4Radiology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States |
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A new diffusion histology imaging (DHI) model is proposed to model crossing fibers considering both intra- and extra-axonal water diffusion, along with extra-axonal isotropic diffusion within an image voxel. Both Monte-Carlo simulation and in vivo MRI data from one healthy volunteer brain were examined to assess whether DHI can resolve crossing fibers while quantifying axonal injury, demyelination, and inflammation. |
| 3580 | Computer 72
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A diffusion MRI pipeline leveraging Nextflow & Singularity: Robust, Efficient, Reproducible in time! |
1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada, 2Imeka Solutions Inc, Sherbrooke, QC, Canada |
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How do we assure a diffusion MRI processing pipeline that is: i) deterministic, i.e. given two runs of the pipeline on the same data, the same output is returned, ii) reproducible in time, and iii) efficient? Diffusion MRI has several processing steps that may not be reproducible between multiple runs. This reproducibility varies because of the parameters, multi-threading and the versions of the tools used. Moreoever, processing time for a large database can take several hours when each step are ran sequentially. To solve these problems, we developed a reproducible and efficient diffusion MRI pipeline based on Nextflow and Singularity. |
| 3581 | Computer 73
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Diffusion Kurtosis Imaging of the Brain with Free Water Elimination |
1Radiology, Miller School of Medicine, University of Miami, Miami, FL, United States |
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In diffusion weighted imaging (DWI) of the brain, a single voxel may contain gray matter (GM), white matter (WM), as well as free water embedded in GM, WM, and cerebrospinal fluid (CSF), each with different diffusion profiles. Free water elimination (FWE) is a method used to separate the free water components from tissue water. In this work, we extend FWE by fitting with a diffusion kurtosis imaging (DKI) model as it is a better descriptor of the non-Gaussian diffusion that occurs in tissue water. |
| 3582 | Computer 74
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A Graph Theory and Spectral Graph Theory Approach to Correlating Tractography with Parkinson’s Disease. |
1Physics, University of Florida, Gainesville, FL, United States, 2Clinical and Health Psychology, University of Florida, Gainesville, FL, United States, 3Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States |
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Diffusion imaging is a potentially powerful tool for analyzing the effect of Parkinson’s disease on the brain. DWI analysis may provide some insight into how Parkinson’s disease may affect low executive or low memory functioning in the brain on a structural level. This research aims to analyze the complexity of the brain connectivity using graph theory and spectral graph theory to correlate structural differences between the brains of Parkinson’s patients with low memory functioning or low executive functioning, and controls. |
| 3583 | Computer 76
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Multi-site diffusion MRI harmonization in the presence of gross pathology: How far can we push? |
1Department of Psychiatry, Harvard Medical School, BOSTON, MA, United States |
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We present a multi-site diffusion MRI (dMRI) data harmonization method using CycleGAN network with segmentation loss (CycleGANS). This method aims to learn an efficient mapping of dMRI signal using rotation invariant spherical harmonics features from the same set of subjects across sites. At the same time, it has potential to learn the tumor pathology (if exists) during harmonization. We compare our CycleGANS network with the CycleGAN network. We show that our CycleGANS network has better multi-site diffusion MRI data harmonization accuracy. Moreover, our method shows up to 60% improvement on the prediction of tumor pathology. |
| 3584 | Computer 77
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Joint distribution of axonal length and diameter quantifies beading in traumatic brain injury |
1National Institutes of Health, Bethesda, MD, United States, 2Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States |
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We present a novel diffusion MRI approach to measure the three-dimensional axonal morphology alterations following traumatic brain injury that results in beading, by modeling axons with a two-dimensional joint distribution of diameters and lengths ($$$D$$$-$$$L$$$). Here we study a segment of ferret spinal cord tissue with known and focal Wallerian degeneration of the corticospinal tract alongside an uninjured control. The results suggest that this approach can be used to specifically detect and quantify axonal beading. |
| 3585 | Computer 78
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Quantitative Sodium Pump Activity, Cellularity, and Cytometry: In Vivo Analytical Pathology from DWI |
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Home, Mill Creek, WA, United States, 3Radiology, University of Colorado Denver, Aurora, CO, United States, 4Surgery, Oregon Health & Science University, Portland, OR, United States |
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With cellular ensembles featuring stochastic geometries, Monte Carlo random walk simulated DWI b-space decays exhibit sensitivity to cell biology parameters measuring membrane Na+,K+‑ATPase [NKA] activity, cell density, ρ, and voxel average cell volume, <V>. Furthermore, the simulation matching the experimental in vivo human cerebral cortex b‑space decay has parameters [cellular water efflux rate constant <kio> = 2 s-1, ρ = 98,000 cells/μL, and <V> = 8.2 pL] in near absolute agreement with the most pertinent literature. Inspecting the common, empirical early decay measure, ADC, of these simulations provides insights into acute and chronic tissue property changes in vivo. |
| 3586 | Computer 79
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Investigation of relationships between systemic inflammation and brain structure in chronic obstructive pulmonary disease (COPD) |
1Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s Uni, Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, London, United Kingdom, 2Institute for Infection and Immunity, St George's University of London, London, United Kingdom, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom, 3Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, London, United Kingdom, 4St George’s, University of London, London, United Kingdom, 5Academic Respiratory Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom, Bristol, United Kingdom, 6Institute for Infection and Immunity, St George's, University of London, London, United Kingdom |
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COPD patients have increased systemic inflammation and increased structural brain damage. 23 COPD patients with coronary artery disease (CAD), and 24 people without COPD matched for smoking, and CAD severity (Gensini score) were studied. COPD patients had more white matter lesions and microstructural tract abnormalities compared to controls. Systemic inflammation (high sensitivity C-reactive protein and fibrinogen) was associated with microstructural brain damage in whole-group analyses. These results suggest a systemic inflammatory process in COPD, which may contribute to white matter abnormalities, consistent with those reported in small vessel disease. |
| 3587 | Computer 80
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Q-Space Trajectory Imaging to Untangle Sources of Microstructural White Matter Changes: Comparison of Schizophrenia Subjects and Healthy Controls |
1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Lund University, Lund, Sweden, 3University Hospital Brno, Brno, Czech Republic, 4Masaryk University, Brno, Czech Republic |
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The recently proposed q-space trajectory imaging (QTI) analysis for multidimensional dMRI acquisitions with free wave forms quantifies domains of variability (size, shape, orientation) that can explain the sources of microstructural changes in the brain. These previously inaccessible domains are used here to disentangle differences observed in the white matter of schizophrenia patients compared to healthy controls. In this population microscopic anisotropy (shape variability) explains changes in fractional anisotropy, in agreement with a hypothesis of white matter degeneration. This study provides a first proof of principal for the feasibility of applying free wave form based sequences on a clinical population. |
| 3588 | Computer 81
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Prostate Cancer Classification by Using Mono Exponential, Stretched Exponential and Kurtosis Model Parameters of Diffusion Signal Decay |
1Department of Urology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States, 2Richard and Loan Hill Department of Bioengineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States, 3Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States, 4Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States |
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Prostate cancer is the most common solid cancer occurring among men in the US. Diffusion-weighted MR imaging plays a complementary role to T2-weighted images in identifying regional changes in prostate tissue. Here, we fit the diffusion decay signal from patients using the stretched-exponential and the kurtosis models and compare the results with MR guided prostate biopsy histology. Our results showed that the kurtosis and stretched exponential models fit to multi-b values diffusion data have the potential to distinguish benign from malignant lesions. These model parameters identify tissue heterogeneity and structures that may be useful in the grading of prostate cancer. |
| 3589 | Computer 82
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Application of DTI and DWI quantitative parameters in differential diagnosis of uterine sarcoma and degenerated hysteromyoma |
1The First Affiliated Hospital of Dalian Medical University, DaLian, China, 2GE Healthcare, MR Research, Beijing, China |
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To investigate the application of diffusion tensor imaging methods, including Diffusion Tensor Imaging(DTI) and Diffusion Weighted Imaging(DWI) in the differential disgnosis of uterine sarcoma and degenerated hysteromyoma. |
| 3590 | Computer 83
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To Detect Metastatic Lymph Nodes Using Intravoxel Incoherent Motion Diffusion-weighted Imaging: A Longitudinal Study on Animal Model |
1Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China, 2Department of Medical Imaging, People's Hospital of Dehong Prefecture, Yunnan, China, 3Philips Healthcare, Guangzhou, China |
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Lymph node (LN) involvement is a dynamic process which may be reflected by intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI). However, there is no such studies so far. Therefore, the potential influence on the diagnosis performance for metastatic LN needs to be investigated. In this longitudinal study on animal models, metastatic LNs evolved in a different pattern from inflammatory LNs pathologically, and IVIM parameters differed between the two groups at particular time points. This indicates that IVIM-DWI can reflect the dynamic pathological changes of LN diseases, and its ability to detect metastatic LN may be affected by the course of disease. |
| 3591 | Computer 84
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Apparent Diffusion Coefficient Using Diffusion Weighted MRI and Biochemical Correlates in Human Breast Cancer |
1Radiological Sciences, UCLA Geffen School of Medicine, Los Angeles, CA, United States, 2Surgery, UCLA Geffen School of Medicine, Los Angeles, CA, United States |
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Multiparametric MRI has been investigated in breast and prostate cancer, and other tumors. We evaluated diffusion weighted imaging in a pilot cohort of 20 malignant and 11 benign breast cancer patients, and 7 healthy women. MR spectra were recorded using an accelerated version of five dimensional echo-planar correlated spectroscopic imaging (5D EP-COSI). Significant decline in ADC values of malignant breast cancer compared to benign and healthy women. There was a negative correlation of choline with ADC values in malignant cancer patients. Our findings suggest that choline and lipids can be reliable biomarkers in addition to widely used ADC. |
| 3592 | Computer 85
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Diffusion Tensor Imaging of Phenylketonuria (PKU) Mouse Brain White Matter Integrity |
1Mallinckrodt Institute of Radiology, Washington University, St Louis, MO, United States, 2Department of Psychological and Brain Sciences, Washington University, St Louis, MO, United States, 3The Edison Family Center for Genome Sciences & Systems Biology and Department of Biomedical Engineering, Washington University, St Louis, MO, United States, 4Alvin J Siteman Cancer Center, Washington University, St Louis, MO, United States |
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DTI was used to evaluate brain white-matter integrity and development in Pahenu2 mice, a model of phenylketonuria (PKU). At two months of age, the volume of the CC in Pahenu2 mice was smaller than that of C57Bl6 controls, and the FA of white matter is significantly lower. For PKU mice on a low-Phe diet, both Daxial and FA of CC and IC increased from two to four months, while these metrics decreased in Pahenu2 mice on a normal diet, suggesting a loss of axonal integrity. Our data suggest that Phe levels are critical to white-matter development in Pahenu2 mice. |
| 3593 | Computer 86
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Apparent diffusion coefficient: Early Indicator of Atheroembolic Renal Disease |
1Peking University First Hospital, Beijing, China |
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Atheroembolic Renal Disease (AERD) is part of a multisystemic disease and has a strong clinical impact on patient and renal survival. Its early diagnosis has a valuable prognostic meaning and huge impact on treatment planning. The tissue edema in early-stage AERD makes DWI a perfect tool for early diagnosis of AERD. In this study, we investigated the role of DWI to noninvasively detect AERD as well as the correlation between ADC values and disease severity identified by histology in an early stage. |
| 3594 | Computer 87
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Longitudinal evaluation of bundle-wise water diffusion changes following axonal degeneration in a region of fiber crossing |
1Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico, 2Escuela de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina, 3Centro de Investigacion en Matematicas, Guanajuato, Mexico |
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Axonal degeneration is a hallmark of many neuropathologies, with a defined time course presenting distinct histological features. In single fiber regions, the tensor model provides reliable information in early and chronic phases of axonal damage. However, said model cannot accurately determine per-bundle characteristics in voxels occupied by axonal populations with different orientations. We evaluated two multiple-fiber methods in an animal model of axonal degeneration (unilateral retinal ischemia) to provide information about the sensitivity of these models related to microstructural changes occuring in the acute and early chronic stages of pathology in a crossing fiber region. |
| 3595 | Computer 88
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Towards MR-based interrogation of the hypoxia-driven insulin resistance mechanism: Adipocytes size estimation. |
1Radiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States |
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It has been suggested that adipocyte hypertrophy plays a key role in the pathogenesis of systemic insulin resistance and type 2 diabetes. A method for quantifying adipocyte size/hypertrophy in-vivo would be a major advance towards understanding the pathogenesis of type 2 diabetes. In-vivo quantification of adipocyte size might be achievable using short time regime diffusion MR, which carries information about size of the system. Herein, we explore the feasibility of measuring adipocyte size based on the diffusion of triglyceride within adipocytes and the principles of the short diffusion time regime. |
| 3596 | Computer 89
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Decoupling effects of fiber dispersion and microscopic anisotropy fundamentally change interpretations of DTI in multiple sclerosis |
1Copenhagen University Hospital Hvidovre, Danish Research Centre for Magnetic Resonance, Hvidovre, Denmark, 2Random Walk Imaging, AB, Lund, Sweden, 3Clinical Sciences, Lund, Department of Radiology, Lund University, Lund, Sweden, 4Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, 5Medical Radiation Physics, Lund University, Lund, Sweden, 6Harvard Medical School, Boston, MA, United States, 7Radiology, Brigham and Women’s Hospital, Boston, MA, United States, 8Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark, 9Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark, 10Danish Multiple Sclerosis Center, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark, 11DTU Compute, Technical University of Denmark, Lyngby, Denmark |
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Fractional anisotropy from diffusion tensor imaging (DTI-FA) has frequently been used to probe changes in white matter microstructure, but is also heavily affected by axonal fiber dispersion. μFA removes fiber dispersion effects and thereby estimates the microscopic anisotropy. Here, we found lower μFA in normal appearing white matter in multiple sclerosis patients as compared with healthy controls. In addition, μFA correlated significantly with age, disability and cognitive performance. These relations could not be established with DTI-FA. Our results indicate that μFA could be used as a powerful biomarker for diseases related to micro-structural changes in white matter as well as in studies of the healthy brain. |
| 3597 | Computer 90
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A Novel Characterization of Traumatic Brain Injury in White Matter with Diffusion MRI Spherical-Harmonics Rotation Invariants |
1Athena Project-Team, INRIA, Sophia Antipolis - Méditerranée, France, 2University of Pennsylvania, Philadelphia, PA, United States, 3Department of Molecular, Cellular, and Biomedical Sciences, CUNY School of Medicine, New York, NY, United States |
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The current DTI-based markers of traumatic brain injury are able to capture affected white matter in the brain, but miss the areas of crossing fibers due to the simplicity of the model. In this work, we use a novel set of spherical-harmonics rotation invariants indices, recently proposed in the literature. We demonstrate that these 12 invariants capture all the information provided by DTI and, in addition, they capture differences in complex white matter beyond DTI measures. This, combined with the clinical feasibility of the method, paves the way for them to be used as better markers of brain injury. |
| 3598 | Computer 91
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Multi-site concordance of diffusion weighted imaging derived metrics, a comparison of fitting algorithms for differentiating whole-mount, pathologically confirmed, prostate cancer of differing Gleason patterns |
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 3Biostatistics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Radiology, University of Michigan, Ann Arbor, MI, United States, 5Radiation Oncology, University of Michigan, Ann Arbor, MI, United States, 6Radiology, Brigham and Women's Hospital, Boston, MA, United States, 7Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, 8Radiology, Mount Sinai, New York, NY, United States, 9Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 10Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 11Institute for Computational Engineering and Sciences, University of Texas, Austin, TX, United States, 12Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 13Advanced Imaging Research Center, Oregon Health Sciences University, Portland, OR, United States, 14Department of Radiology, University of Washington, Seattle, WA, United States, 15Urological Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, 16Pathology, Medical College of Wisconsin, Milwaukee, WI, United States |
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We present a multi-site study measuring the ability of various software platforms to fit diffusion weighted imaging (DWI) models for differentiating prostate cancer (PCA) of different Gleason patterns. A dataset of DWI collected from 33 PCA patients was distributed to ten collaborating groups who fit the multi-b DWI models with onsite software and submitted the derived parametric maps to a central analysis site. Each map was aligned to the T2-weighted image and compared to pathologist annotations of whole-mount prostate samples. A statistical analysis was performed for similarity of the quantitative values, and the ability of each metric to differentiate PCA. |
| 3599 | Computer 92
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Optimizing Imaging Protocols for Structural Connectomics in Mouse Models of Neurological Conditions |
1Radiology, Duke University Medical Center, Durham, NC, United States, 2Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States |
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Network approaches provide sensitive biomarkers for neurological conditions such as Alzheimer’s disease. Mouse models provide tools to dissect vulnerable circuits at prodromal stages, and to assess the effects of interventions. We have simulated mouse brain structural connectomes, balancing angular, spatial resolution and scan time. Specifically, we evaluated protocols with 6, 12, 15, 20, 30, 45, 60 and 120 angles; and 3 voxel sizes at 43, 86 and 172 µm. Our results indicate schemes using 46 or 60 diffusion directions, acquired at 86 µm resolution achieve a good cost/performance balance relative to a high spatial, high angular resolution sampling scheme. |
| 3600 | Computer 93
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THE EFFECT OF MATERNAL OXYGENATION ON PLACENTAL PERFUSION IN NORMAL GROWTH AND FETUS GROWTH RESTRICTED FETUSES BY USING IVIM MRI |
1Radiology Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, 2MR Collaboration, United Imaging Healthcare, Shanghai, China |
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The aim of this study was to determine whether IVIM-MRI could evaluate oxygen inhalation therapy in placental perfusion during maternal hyperoxygenation in FGR and normal growth fetuses. |
| 3601 | Computer 94
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Free Water Characterization of Peritumoral Regions in Primary and Secondary Brain Neoplasms |
1Penn Patho-Connectomics Lab, Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Synaptive Medical, Victoria, BC, Canada, 3Neurosurgical Oncology, University of Pennsylvania, Philadelphia, PA, United States |
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There is a growing interest in characterizing the peritumoral regions in neoplasms, in order to distinguish primary and secondary neoplasms, improve tractography for surgical planning, and create radiomic markers of infiltration. Free water estimation is expected to reflect the differences in water content of the peritumoral region between these tumor types. In this work, we compare glioblastoma (primary) and metastatic (secondary) tumors based on their free water estimated using standard clinical diffusion MRI (dMRI). Results demonstrate significant difference in these tumor types based on the free water measures, fractional anisotropy post-correction and the coverage of the peritumoral region by tractography. |
| 3602 | Computer 95
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Diffusion Weighted MRI Characterization of Effects of Sex and APOE Genotype in a Mouse Model |
1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 2Department of Clinical Therapeutics, USC School of Pharmacy, University of Southern California, Los Angeles, CA, United States, 3Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States, 4Department of Pharmacology, University of Arizona, Tucson, AZ, United States |
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Structural and diffusion MRI (dMRI) analyses can be used to characterize neurodegeneration during Alzheimer’s disease progression. Male and female mice with a targeted replacement of mouse APOE gene with humanized APOEε3 or APOEε4, underwent behavioral, transcriptomic and imaging analyses. Postmortem MRI of fixed brains included high resolution T2-weighted and diffusion weighted imaging. Structural volume assessment revealed that APOE genotype and sex have a significant impact on regional brain volumes. dMRI quantified white matter microstructural differences between APOEε3 or APOEε4 females/males which maybe cross-validated with transcriptomic and behavioral findings. Further confirmation of microstructural assessment is pending by electron micrographs. |
| 3603 | Computer 96
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MRI Assessment of Sex Differences in APOEε4 Knock-in in Rat Brains |
1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 2Department of Clinical Therapeutics, USC School of Pharmacy, University of Southern California, Los Angeles, CA, United States, 3Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States, 4Department of Pharmacology, University of Arizona, Tucson, AZ, United States |
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Using a humanized APOEε4 gene knock-in ex-vivo rat brain model, the individual and combined impact of sex and APOEε4 genotype on white matter microstructure was measured using high T2-weighted and diffusion weighted MRI. Total brain volumes showed a significant sexual dimorphism in WT as well as APOEε4 animals, with the females having significantly lower volumes. Both volumetric and diffusion MRI measures were able to show trends of sexual dimorphism as well as genotype effect. These findings were supported with metabolomic data suggesting reduction in glucose utilization and possible shift to fatty acids derived from white matter catabolism as a fuel source. |
| 3604 | Computer 97
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Multicomponent Analysis of High b-value Diffusion-Weighted MRI for Tracking Progression of Amyotrophic Lateral Sclerosis in A Mouse Model |
1Department of Electrical & Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States, 2Research Resources Center, University of Illinois at Chicago, Chicago, IL, United States, 3Department of Physiology, Northwestern University, Chicago, IL, United States, 4Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 5Department of Radiology, Northwestern University, Chicago, IL, United States |
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Amyotrophic lateral sclerosis (ALS) is a progressive disease of motor neuron degeneration in brain and spinal cord with an unknown etiology. Diffusion MRI has potential to track the disease progression in ALS due to the technique’s intrinsic advantages in detecting structure changes and non-invasive nature. In this study, we investigated the feasibility of analyzing multiple high b-value diffusion-weighted images using a non-negative least squares method (requiring no prior assumptions about components) and a bi-compartment model with restricted and hindered diffusion components. Both methods were able to detect alterations of spinal cord in the G93A-SOD1 mouse model of ALS. |
| 3605 | Computer 98
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High B-value In-vivo DTI for Early Detection of Cerebral Microstructure Alteration: Application to Hippocampus Lesions in a Mouse Model of Multiple Sclerosis |
1INCIA, Université de Bordeaux, CNRS, Bordeaux, France, Metropolitan, 2Neurocentre Magendie, INSERM, U1215, Bordeaux, France, Metropolitan, 3CHU de Bordeaux, Bordeaux, France, Metropolitan, 4Institut des sciences cognitives Marc Jeannerod, UMR 5229, CNRS-université Lyon1, Bron, France, Metropolitan |
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Few reports have highlighted the value of DTI achieved with a strong water-diffusion weighting to capture early and diffuse changes in cerebral microstructure of the white-matter. This study investigates the benefit of DTI with b-value=2700s/mm² to detect microstructure lesions of the hippocampus in a mouse model of multi-sclerosis. High b-value DTI allowed to detect microstructure changes invisible using DTI achieved with classical b-value=1000s/mm². In grey-matter tissues with complex architecture such as hippocampus, an increase of b-value appeared to be more relevant to monitor the microstructure changes compared to an increase of the number of diffusion directions. |
| 3606 | Computer 99
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Diffusional Kurtosis Imaging of Temporal Lobe Gray Matter as a Biomarker of Neurological Disease: Schizophrenia and Autism Spectrum Disorder |
1Radiology, Center for Biomedical Imaging, New York, NY, United States, 2Sackler Institute of Graduate Biomedical Sciences, New York, NY, United States, 3Psychiatry, New York University School of Medicine, New York, NY, United States |
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In this study, we employed diffusion kurtosis imaging (DKI) to test for differences in gray matter (GM) microstructure in schizophrenia (SZ) and autism spectrum disorder (ASD). Significantly increased metrics of DKI were found in SZ compared to HC participants, while significantly decreased metrics of DKI were found in ASD compared to HC in the temporal lobe and sub-lobar temporal regions of interest (ROIs). In vivo DKI metrics appear to be sensitive to GM microstructural pathology in SZ and ASD and may provide new information on the neural underpinnings of these disorders. |
| 3607 | Computer 101
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Resting-state diffusion fMRI bears strong resemblance and only subtle differences to BOLD fMRI |
1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland |
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Diffusion fMRI (dfMRI) is a presumably non-BOLD technique sensitive to transient microstructural changes underlying neural activity. Previous task-fMRI studies have assessed the characteristics of the dfMRI signal and potential BOLD contamination, with conflicting results. Here we acquired resting-state fMRI data with five protocols with incrementally reduced BOLD contributions and analyzed the characteristics of resting-state networks and functional connectivity using model-free approaches. We report dfMRI data does not contain fundamentally different information to BOLD-fMRI, with the exception of a few regions that switch from anti- to positively-correlated. Future work will focus on removing any remaining BOLD contribution from the dfMRI acquisition. |
| 3608 | Computer 102
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Diffusion Kurtosis Image in assessment of 3D Cell Culture |
1Master's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, 3Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, 4Department of Radiology, China Medical University Hospital, Taichung, Taiwan |
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A non-Gaussian kurtosis model has been shown to take into account tissue heterogeneity and two relative imaging biomarkers namely, the kurtosis coefficient and the corrected diffusion coefficient can be quantified. In this study, 3D cell culture with hydrogels ECM was used to investigate whether DKI may provide information on these microenvironmental parameters and the microenvironment-associated metastatic propensity of tumors. Our results demonstrated DKI-MRI may provide the potential biomarkers on the change of microenvironment in the application of 3D cell culture experiment. |
| 3609 | Computer 103
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Does cerebrospinal fluid pulsation affect DWI thermometry?: healthy volunteer study |
1KPUM, Kyoto, Japan, 2KPUM Hospital, Kyoto, Japan |
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Diffusion-weighted imaging (DWI) based thermometry has a potential to be a non-invasive method of temperature measurement for the deep inside of human brain. Nevertheless, the DWI at lateral ventricle in the brain might be influenced by the pulsation flow of cerebrospinal fluid (CSF), which is motivated by heartbeat. The purpose of this study was to investigate the influence of pulsation flow on brain DWI thermometry for healthy subjects. Comparisons were performed among ΔT at three CSF speed selections (slow vs. fast vs. random). There was no significant difference in ΔT among the CSF speed and volume on healthy subjects. |
| 3610 | Computer 104
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Abnormal cerebellar connectivity within the motor subnetwork in MSA with cerebellar dysfunction |
1Symbiosis Centre of Medical Image Analysis, Symbiosis International University, Pune, India, 2Department of Clinical Neurosciences and Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India, 3Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India, 4Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, India |
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Multiple system atrophy with cerebellar features (MSA-C) is a distinct subtype of MSA characterized by predominant cerebellar symptoms. Neuroimaging studies have demonstrated cerebellar abnormalities; however, abnormality of structural connectivity of the motor subnetwork has not been studied and this study aims to investigate this aspect. We observed impairment in the structural segregation, integration and network resilience with significantly reduced nodal strength and connectivity in several cerebellar as well as non-cerebellar regions that correlate with UMSARS scores. Our findings provide definitive evidence of abnormalities that may be causally implicated in the motor features of cerebellar dysfunction and Parkinsonism observed in MSA-C. |
| 3611 | Computer 105
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Propagation of Bias in Moment-Matching Based Standard Model Parameter Estimation |
1Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 2Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, 3Champalimaud Neuroscience Programme, Lisbon, Portugal |
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Moment-matching is one proposed approach for estimating Standard Model parameters which partly overcomes the issues of the model’s notoriously shallow fitting landscape. The method achieves robustness by matching the model’s moments to the cumulants of the data determined by diffusion kurtosis imaging which is stable and clinically feasible. However, estimates of cumulants generally suffer from bias due to the use of finite b-values. Here, it is demonstrated that this bias propagates to the model-parameter estimates resulting in substantial inaccuracy even for small b-values. |
| 3612 | Computer 106
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Random Walks in Stochastic Geometries |
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Surgery, Oregon Health & Science University, Portland, OR, United States |
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Monte Carlo random walk simulations of water molecule displacements in realistic cell ensembles are presented. Within an ensemble, the cells have stochastic distributions of sizes, shapes, and interstitial spacings. The probability of molecules permeating the cell membrane is varied. The irreducible, fundamental system parameters are the cell density, ρ, the mean cell volume, <V>, and the steady-state cellular water efflux rate constant, <kio>. Even though the self-diffusion coefficient is that of pure water, non-Gaussian displacements are observed. |
| 3613 | Computer 107
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Characterising tissue heterogeneity in cerebral metastases using multi-shell multi-tissue constrained spherical deconvolution |
1School of Psychology, Cardiff University Brain Research Imaging Centre, Cardiff, United Kingdom, 2Velindre University NHS Trust, Velindre Cancer Centre, Cardiff, United Kingdom, 3Department of Cancer and Genetics, Cardiff University School of Medicine, Cardiff, United Kingdom, 4School of Psychology, Australian Catholic University, Victoria, Australia |
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Considerable attention has focused on characterizing brain tumours using diffusion tensor imaging, and only more recently using advanced modelling techniques. Building on the observation that metastatic tumors exhibit different signal intensities depending on their histological/cellular composition, we investigate how multi-shell multi-tissue constrained spherical deconvolution can characterise tissue heterogeneity within brain metastases. |
| 3614 | Computer 108
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Reproducibility of tractography based on fibre orientation distribution and anatomical constraints applied on paediatric diffusion MRI. |
1ExpORL, KU Leuven, Leuven, Belgium, 2Research and Development, icometrix, Leuven, Belgium |
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Tractography is known to be sensitive to technical variations but might also be sensitive to issues related to paediatric data, such as head motion. We assessed the reproducibility in paediatric data of the probabilistic tractography algorithm based on fibre orientation distribution and anatomical constraints that enables to deal with crossing fibres and to reconstruct tracts with more anatomical accuracy. Our results showed that the reproducibility of this approach when it is applied on paediatric data is negatively affected by younger age and by head motion but can still achieve good reproducibility for selected tracts. |
| 3615 | Computer 109
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Cardiac Fiber Mobility During Contraction Using High Resolution Diffusion Tensor MRI |
1Radiological Sciences Lab, Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Radiological Sciences, University of California, Los Angeles, CA, United States, 3Physics and Biology in Medicine IDP, University of California, Los Angeles, CA, United States, 4Department of Bioengineering, University of California, Los angeles, CA, United States |
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The main cardiomyocyte aggregate orientation, represented by the Helix Angle, remains poorly described in vivo during contractionas it is affected by the imaging resolution and thus by a change of wall thickening. This work evaluated the effect of the imaging resolution using a numerical phantom and ex vivoscans on porcine hearts. High-resolution cDTI was acquired in vivoto measure the transmural mobility of Helix Angle at three cardiac phases. A strong steepening of Helix Angle was observed as the resolution decreased in simulation and ex-vivo. A significant change in the Helix Angle distribution was observed during contraction. |
| 3616 | Computer 110
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Metabolite diffusion weighted imaging with golden angle radial echo planar spectroscopic imaging |
1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2C.J. Gorter Center for High Field MRI Research, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 3Philips Healthcare, Copenhagen, Denmark, 4Center for Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark |
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Diffusion weighted spectroscopy (DWS) is a promising tool for investigating compartment specific microstructure in heterogeneous tissues. Unlike water abundant in all cellular spaces, the mobility of metabolites provides a window into the microstructure of specific cell types. Multi-shot sequences for diffusion spectroscopic imaging suffer from translation induced phase fluctuations. This has previously been addressed with additional phase navigators. In this work we propose self navigated metabolite diffusion weighted spectroscopic imaging using golden angle radial echo planar gradient readouts with semi-LASER voxel localization. Initial data shows good spatial localization and spectral quality. |
| 3617 | Computer 111
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Needle in a Haystack: Finding connections of interest in the precentral gyrus from diffusion MRI based connectomics |
1Département de médecine nucléaire et radiobiologie, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Université de Sherbrooke, Sherbrooke, QC, Canada |
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DMRI tractography and connectomics aim to create comprehensive maps of all neural circuitry in the brain, however, dMRI is a false-positive prone imaging modality. Yet, as it is the only non-invasive and in-vivo method to indirectly study the white matter connectivity of the brain it is heavily utilized. DMRI-Connectomic analyses often end with a “big data” problem, as there are many possible connections. Moreover, this data is likely populated by false-positive connections. By utilizing data-driven criteria to filter matrices this work attempts to narrow the “search window” by adding criteria on which we can discard “connections” or consider them potential candidates for further investigation. Such judgements may also lead to connections being evaluated as true or false-positives. |
| 3618 | Computer 112
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Characterization of white matter asymmetries in the healthy human brain using diffusion MRI fixel-based analysis |
1Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2Florey Department of Neuroscience and Mental health, Melbourne, Australia, 3The University of Sydney, Sydney Imaging, Sydney, Australia, 4The University of Sydney, School of Aerospace, Mechanical and Mechatronic Engineering, Sydney, Australia |
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The diffusion tensor model has been used extensively to study asymmetry in various regions of the human brain white matter. However, given the limitations of the tensor model, the nature of any underlying asymmetries remain uncertain, particularly in crossing |
| 3619 | Computer 113
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Toward prognostic sensitivity of DTI to cognitive outcomes following physical exercise interventions. |
1Aging, Mobility and Cognitive Neuroscience Laboratory, University of British Columbia, Vancouver, BC, Canada, 2Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute and University of British Columbia, Vancouver, BC, Canada |
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Diffusion Tensor Imaging (DTI) is widely implemented in clinical research, yet, its prognostic value in brain and cognitive health remains uncertain. Prospective estimation of the effectiveness of interventions, such as physical exercise, can increase cost-effectiveness of treatment, thus, maximizing the impact of accessible modifiable preventive factors in improving health outcomes in the general population. We examined DTI in relationship to cognitive outcomes of physical activity intervention. This is the first study to show that white matter integrity related to sleep efficiency can be an early predictor of the cognitive outcomes of physical exercise intervention. |
| 3620 | Computer 114
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Assessment of Microstructural Changes Induced via Repeated Videogame Training as a Measure of Neuroplasticity in Normal Developing, College-age Brains |
1University of Wisconsin-Madison, Madison, WI, United States, 2Indiana University-Bloomington, Bloomington, IN, United States |
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In this study, diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) were used to assess brain changes in white matter regions as a result of repeated videogame training. In a cohort playing a simulated race car game, we observe evidence of microstructural changes in tracts associated with working and long-term memory. Subjects playing a guitar simulation game, experienced changes in regions associated with attention, visuomotor learning, and proprioception of the limbs. This study demonstrates that diffusion MRI is promising for characterizing subtle brain changes associated with learning. |
| 3621 | Computer 115
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Finding the Surrogate Biomarkers of Glioma Infiltration in the Normal Appearing White Matter adjacent to Tumor using Neurite Orientation Dispersion and Density Imaging (NODDI) |
1Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan, 2Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei Veterans General Hospital, Taipei, Taiwan, 3Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan |
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This work addresses the study in glioma, where Diffusion Tensor Imaging (DTI) provides incoherent information while Neurite orientation dispersion and density imaging (NODDI) may improve the microstructural characterization. Glioma recurrences are mostly located at the margin of the resection cavity as peritumoral area. NODDI, using a compartment-based biophysical model, would potentially provide specific surrogate biomarkers for the microscopic foci of glioma infiltration better than DTI. NODDI reveals that glioma cells can extend beyond the bulk tumor and peritumoral edema into |
| 3622 | Computer 116
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Assessing inter-vender reproducibility of diffusion tensor imaging of the spinal cord for multi-center imaging studies |
1Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba City, Japan, 2radiology, Chiba University Hospital, Chiba City, Japan, 3radiology, Asahi General Hospital, Asahi City, Japan |
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In this study, we assessed the inter-vendor precision of diffusion tensor imaging (DTI) metrics using consensus acquisition protocol across 3T scanners from 3 main vendor at the two sites. The data were acquired from the traveling human healthy volunteer. DTI data and anatomical images were also acquired and imaging data were processed using the Spinal Cord Toolbox (SCT). Relatively higher inter vender reproducibility of fractional anisotropy (FA) in and cross-sectional area were demonstrated and it is considered feasible to conduct multicenter DTI studies of the spinal cord using FA value as biomarker and SCT as postprocessing tool. |
| 3623 | Computer 117
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Performance of Intravoxel incoherent motion (IVIM) imaging in the curative effect evaluation of diabetic nephropathy - A preliminary study |
1AFFILIATED HOSPITAL OF SHAANXI UNIVERSITY OF CHINESE MEDICINE, Xianyang, China, 2Siemens Healthcare, Erlangen, Germany, 3MR Scientific Marketing, Siemens Healthcare, Xi'an, Xi'an, China |
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Diabetes has nowadays become one of the major public health problems. Early detection and intervention is crucial to delay the progress of Diabetic kidney disease. In this study, IVIM imaging was used to evaluate the renal-cortex- and medulla-related parameter changes before and after the treatment of diabetic nephropathy. It was found that after treatment, D, f, D *and ADC values were increased, indicating the improved microvascular perfusion. |
| 3624 | Computer 118
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Diffusion MRI characterization of Proton-therapy-induced brain tissue changes: a case study |
1CIMeC - Center for Mind/Brain Sciences, University of Trento, Trento, Italy, 2Proton-Therapy Unit, S. Chiara Hospital, APSS, Azienda Provinciale per i Servizi Sanitari, Trento, Trento, Italy, 3Radiology Unit, Santa Maria del Carmine Hospital, Rovereto (Trento), Italy, 4Departments of Psychiatry and Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States |
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Radiotherapy-induced neurotoxicity may be life threatening and its characterization is crucial for cancer treatment management, especially in early treatment phases. Diffusion MRI allows to assess non-invasively microstructural changes occurring with radiation treatment, which are of interest in relation to local absorbed dose and cognitive changes. Proton therapy (PT) offers the promise of more focal tumor damage relative to conventional radiotherapy. However, few studies have evaluated how it affects brain microstructure. As part of an ongoing longitudinal study, we present the first available data of 5 acquisitions along PT course showing a possible treatment-related “necrosis-like” effect during treatment. |
| 3625 | Computer 119
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Diffusion-Relaxation Imaging with B-tensor Encoding using the Cumulant Expansion |
1BWH Radiology, Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Lund University, Lund, Sweden |
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Quantitative T2 and diffusion imaging provide important information about tissue microstructure. However, a joint knowledge of quantitative T2 and diffusion-derived measures can provide richer information about the microstructure that is not accessible when using these modalities independently. The standard approach for estimating the joint distributions of the T2-diffusion relies on the inverse Laplace transform. This transform is known to be unstable and difficult to invert. In this work, we introduce an alternative approach based on cumulant expansion, and extend the recently proposed multidimensional diffusion MRI framework ``Q-space Trajectory Imaging" (QTI) to include T2-relaxation modeling. The cumulants of the expansion include estimates of mean diffusion and T2 relaxation, as well as their variance and covariance. We demonstrate the feasibility of this approach in a healthy human brain. |
| 3626 | Computer 120
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Qualitative Comparison of Calculated and Measured Ultra-High b-Value Diffusion-Weighted Images in the Assessment of Clinically Significant Prostate Cancer. |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Urology, University Hospital Heidelberg, Heidelberg, Germany, 3MR Physics, University Hospital Erlangen, Erlangen, Germany, 4Medical Physics, German Cancer Research Center, Heidelberg, Germany |
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To qualitatively compare measured and calculated ultra-high b-value (UHB, b-value up to 4000 s/mm2) DWI for detection of clinically significant prostate cancer. UHB-DWI was acquired in 55 patients at 3T in addition to standard DWI (S-DWI) extrapolated to UHB b-values. Two raters R1 and R2 independently assessed DWI and ADC in combination with T2w images. Lesion visibility was best on ultra-high b-value images monoexponentially extrapolated (ME-DWI) from S-DWI and equal on S- and UHB-ADC. The experienced rater was better able to adapt the improved lesion visibility on ME-DWI into the lesion detection task and utilized it for superior predictive performance. |
| 3627 | Computer 121
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Qualitative Diagnosis of Complex Ovarian Tumors Using Diffusion Weighted Imaging and Dynamic Contrast-Enhanced Magnetic Resonance Imaging: Correlation with MR Features and Pathology |
1Radiology, Department of Radiology, Fujian Provincial Maternity and Child Health Hospital, Fuzhou, China |
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Aims: To evaluate the effectiveness of diffusion weighted imaging and dynamic contrast enhanced magnetic resonance imaging in qualitative diagnosis of complex ovarian tumors． Methods: Semi-quantitative parameters of maximal slope of time-signal intensity curve and apparent diffusion coefficient measurements of diffusion-weighted imaging obtained from the tumor solid regions in 65 cases confirmed complex ovarian tumors were done． Results: A cut-off value of 1．61 × 10－3mm2 /s for ADC was used in differentiating invasive from borderline tumors．Optimal threshold value for maximal slope was 4．58% per second identifying benign and malignant tumors. Conclusion: Maximal slope value of time-signal intensity curve is the best index in distinguishing malignant from benign ovarian complex tumors，and ADC value of the solid component is the best index in differentiating invasive from borderline ovarian complex tumors． |
| 3628 | Computer 122
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Directional Intravoxel Incoherent Motion (IVIM) MR in Rodent Brain |
1Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States |
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The measurement of white matter flow, which is directional along the neuronal fibers, is challenging due to inherent limitations of low sensitivity and signal-to-noise ratio with arterial spin labeling(ASL)- and dynamic susceptibility contrast(DSC)-MRI acquisitions mainly due to low blood volumes. Recently, |
| 3629 | Computer 123
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Application of Spinal Cord White Matter Tract Integrity Quantification with Atlas-based Analysis in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder |
1Radiology, Juntendo University School of Medicine, Tokyo, Japan, 2Radiology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan, 3Neurology, Juntendo University School of Medicine, Tokyo, Japan, 4Siemens Japan K.K, Tokyo, Japan, 5NeuroPoly Lab, Polytechnique Montreal, Montreal, QC, Canada |
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We investigated both branches (Da ≤ De,∥ or Da > De,∥) of Kurtosis-based white matter tract integrity to distinguish microstructural changes in the spinal cords of patients with MS and Neuromyelitis Optica. FA and AWF were significant higher and MD was significant lower in spinal cord white matter in MS (P=0.009, 0.024, 0.032, respectively). Di,axial, Di,radial and De,radial of spinal cord white matter in MS were significant lower (P=0.009, 0.024, 0.032, respectively,) in Branch 2(Da > De,∥) in MS. There was no significant difference in Branch 1 ( Da ≤ De,∥) metrics. |
| 3630 | Computer 124
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Delineation of thalamic substructures in ultra-high b-value DWI-measurement with reasonable acquisition time |
1Diagnostic and interventional Neuroradiology, University Hospital Tuebingen, Tuebingen, Germany |
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The purpose of this study was to evaluate the capability of optimized and faster ultra-high b-value DWI in separating and identifying intrathalamic substructures compared to a previously described protocol. 7 subjects underwent MR-imaging, including T1 MPRAGE and two DWI sequences at 0 and 5000 s/mm2. DWI was performed with 64 directions and 5 averages (17:56 min) and with 6 directions and 25 averages (8:23 min). Intrathalamic substructures were semi-automatically delineate 4mm above AC/PC line. Accordance between the original sequence and the new speeded-up measurement was high. Acquisition time was reduced by more than 50 % with comparable results. |
| 3631 | Computer 125
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The value of Mean Apparent Propagator (MAP)-MRI in the diagnosis of hippocampal sclerosis |
1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2MR Scientific Marketing, Siemens Healthcare, Shanghai, China, Shanghai, China |
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This study aimed to explore the value of mean apparent propogation (MAP)-MRI parameters in the diagnosis of hippocampal sclerosis. By comparing the MAP-MRI parameters of hippocampus from both the hippocampal sclerosis patients and the healthy controls, the study found that the MAP-MRI parameters showed high consistency with pathological results, particularly for MSD and QIV. It suggests that MAP-MRI may be used as a diagnostic method with high sensitivity and specificity besides magnetic resonance spectroscopy(MRS) in the future. |
| 3632 | Computer 126
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Tunable diffusion kurtosis in lamellar vesicle suspensions toward development of quantitative phantom surrogate of tumor microenvironment |
1Radiology, University of Michigan, Ann Arbor, MI, United States |
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A set of materials based on nanostructured lamellar vesicles with restricted diffusion compartments is constructed to achieve tunable diffusion kurtosis behavior. The observed apparent diffusion (Dapp) and kurtosis (Kapp) model parameters span the range of values found in vivo. Effect of vesicle population, size, and porosity is studied for estimated diffusion parameters. These nanostructured systems provide an ideal platform for a diffusion kurtosis phantom used to validate quantitative imaging protocols and results. |
| 3633 | Computer 127
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Simulation of Intravoxel Incoherent Perfusion Signal using a Realistic Capillary Network of a Mouse Brain |
1University Hospital Zürich, Zürich, Switzerland, 2Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Switzerland, 3Institute for Biomedical Engineering, ETH and University of Zürich, Zürich, Switzerland |
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The microscopic origin of the IVIM perfusion signal is not well understood. We simulated blood motion in three realistic microvascular networks obtained by two-photon laser microscopy in mouse brain and computed the effect of this motion on the diffusion-weighted signal MR signal for b-values between 0 and 1000 s/mm2. We found pseudo-diffusion coefficients D* in the range of in vivo measurements. Further, the signal decay was strongly dependent on the specific type of vessel (capillary,arterioles/venules or pial vessels) and on the global vessel diameters of the network. |
| 3634 | Computer 128
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Taxon anisotropic phantom delivering human scale parametrically controlled diffusion compartments to advance cross laboratory research and calibration. |
1University of Pittsburgh, Pittsburgh, PA, United States, 2Psychology Software Tools, Pittsburgh, PA, United States |
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Details a novel bi-component polymer Taxon (textile water filled tubes) anisotropic diffusion phantom providing 0.8 microndiameter tubes, packing density of 106 per mm2, water fraction of over 45% matched to human axon histology with parametric control of water compartment (intra/extra axon), size, density, angle dispersion that can be manufactured to supply hundreds of laboratories. Observed human tissue range FA (0.6-01.0), MD and RD in observed range. Providing ground truth measurement to advance and calibrate anisotropic diffusion measurement. Micro-CT and diffusion MRI indicate high water content in agreement with MRI and non MRI measurements. |
| 3635 | Computer 129
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Phantoms for Diffusion Simulations: Multi-Objective Differential Evolution for Realistic Numerical (MODERN) Phantoms. |
1Signal Processing Lab (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Centre for Magnetic Resonance, University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark, 4European Synchrotron Radiation Facility, Genoble, France, 5Radiology Department, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland |
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The following work presents a novel, generally applicable framework (MODERN) which takes, as input, statistics from histology and automatically generates biologically plausible numerical phantoms whose morphological features are optimized to match the input statistics. As a proof of concept, MODERN is used to generate three-dimensional geometrical meshes representing a bundle configuration of axons which can be immediately integrated into Monte Carlo simulations for diffusion MRI acquisitions. The obtained features of the optimised phantoms are shown to match those from the input values. The statistics used were obtained from axonal segmentations from synchrotron imaging. |
| 3636 | Computer 130
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Axon-mimicking hydrophilic fibre phantoms for diffusion MRI |
1Quantitative Biomedical Imaging Laboratory, The University of Manchester, Manchester, United Kingdom, 2School of Materials, The University of Manchester, Manchester, United Kingdom, 3Developmental Imaging and Biophysics, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 4National Physical Laboratory, Teddington, London, United Kingdom, 5College of Textile and Clothing Engineering, Soochow University, Suzhou, China, 6Bioxydyn Limited, Manchester, United Kingdom |
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We report the development of an axon-mimicking phantom composed of hydrophilic hollow microfibres, and evaluate its potential for validating clinical diffusion MRI. Microfibers were fabricated by the co-electrospinning (co-ES) of polycaprolactone (PCL)-polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide (PEO) as core, and characterized by scanning electron microscopy (SEM). Three material samples were constructed and included in the phantom within a water bath. SEM images reveal that PCL-PSi fibres in the samples were uniaxially aligned and hollow, with a similar distribution of pore sizes to axons in vivo. MR measurement shows similar anisotropic diffusion behaviour in each sample. |
| 3637 | Computer 131
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Multisite evaluation of repeatability and stability for a novel quantitative diffusion kurtosis phantom |
1Radiology, University of Michigan Health System, Ann Arbor, MI, United States, 2Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 3Columbia University Irving Medical Center, New York, NY, United States, 4Medical Physics and Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States |
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Multi-center clinical trials utilizing quantitative diffusion kurtosis imaging (DKI) protocols require accurate, precise, and stable phantoms for validation of derived imaging metrics. This study examines the precision and reproducibility of isotropic (i)DKI parameters obtained from a phantom based on nanostructured vesicles that restrict diffusion and mimic tissue cellularity. Ten test-retest iDKI studies were performed on four scanners at three imaging centers over a six-month period. The tested prototype phantoms exhibited physiologically-relevant and highly-repeatable apparent diffusion and kurtosis parameters. Achieved precision was sufficient to characterize thermal and temporal stability trends to guide robust quantitative iDKI phantom production. |
| 3638 | Computer 132
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Comparison of dMRI Models for Skeletal Muscle Microstructure Estimation with Numerical Simulations and Porcine Phantom |
1Mechanical Science and Engineering, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Beckman Institute for Advanced Science and Technology, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 4Radiology, Carle Foundation Hospital, Urbana, IL, United States, 5Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States |
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Four models used to estimate skeletal muscle microstructure from |
| 3639 | Computer 133
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Towards a more realistic and flexible white matter numerical phantom generator for diffusion MRI simulation |
1Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom, 2Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal |
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We present a novel method for the generation of realistic white matter numerical phantoms with controllable morphology, and more realistic orientation-dispersion and packing-density. A shift of paradigm is proposed: rather than ‘packing fibres’, our algorithm ‘grows fibres’ contextually and efficiently, avoiding intersection between fibres. The potential of the method is demonstrated by reaching the highest orientation-dispersion and packing-density ever. The flexibility of the method is demonstrated with simulations of diffusion-weighted MR signal in three example substrates with differing orientation-dispersions, packing-densities and permeabilities. A proof-of-concept application is presented to investigate the impacts of undulation and beading on the intra-axonal axial diffusivity. |
| 3640 | Computer 134
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Quantitative Comparison of 6 different Diffusion Weighted Imaging Approaches using NIST Diffusion Phantom |
1Medical College of Wisconsin, Milwaukee, WI, United States, 2GE Healthcare, Waukesha, WI, United States |
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The application of diffusion weighted imaging (DWI) is rapidly increasing in musculoskeletal system. DWI is useful in imaging diverse range of musculoskeletal pathologies like soft-tissue tumors, bone lesions, vertebral fractures pre and post treatment follow up. In this work, our goal is to quantitatively compare the accuracy of ADC estimation of EPI, and PROPELLER based techniques. We also optimize the imaging parameters for PROPELLER and MSI-PROPELLER techniques and provide a correction method to improve the accuracy of ADC estimation. |
| 3641 | Computer 135
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Validation and Estimation of crossing angles of fiber bundle with different density using hollow textile-based phantom |
1Learning Research and Development Center, University of Pittsburgh, Pittsburgh, PA, United States, 2Biological Cybernetics, Max Planck Institute, Tuebingen, Germany, 3Psychology, Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, 4Neurosurgery, Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States |
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A textile-based hollow fiber (taxon) MRI phantom ( |
| 3642 | Computer 136
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Novel Atlas of Fiber Directions Built From Ex Vivo DT images of Porcine Hearts |
1University of Ontario Institute of Technology, Oshawa, ON, Canada, 2Sunnybrook Research Institute, Toronto, ON, Canada, 3INRIA Sophia Antipolis, Sophia Antipolis, France |
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In this study we successfully created the first high-resolution cardiac Diffusion Tensor (DT) imaging-based fiber atlas from porcine hearts. Furthermore, we laid the foundation of a framework for building a statistical cardiac atlas by computing an average cardiac geometry from a small database (N=8) of explanted porcine hearts without the need for selecting landmarks, transforming the diffusion tensors of subjects, and obtaining the associated average DT field and fiber architecture. The fiber atlas can be used for personalized electro-mechanical simulations of cardiac function (in anisotropic models when DT data is not available), and aid in diagnosis or therapy guidance procedures. |
| 3643 | Computer 137
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OGSE diffusion weighted imaging of epidermoid cysts: 3D Monte Carlo simulation |
1Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan, 2Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan, 3LPixel Inc., Tokyo, Japan |
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Diffusion weighted imaging with shorter diffusion time using oscillating gradient spin echo (OGSE) may reveal microstructural features among brain disorders. Here we observed DTI eigenvalues in four patients with epidermoid cysts. The values measured by OGSE were higher than those measured by pulsed gradient spin echo (PGSE; used in conventional MRI), indicating restricted diffusion due to spatial restriction and/or viscosity. The results of our Monte Carlo simulation based on the pathological feature of epidermoid cysts suggest that spatial restriction of multiple ellipsoids formed by keratin filaments as well as viscosity and water exchange should influence the extent of restricted diffusion. |
| 3644 | Computer 138
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Studying the effect of membrane permeability with a GPU-based Bloch–Torrey simulator |
1Department of Aeronautics, Imperial College London, London, United Kingdom, 2Cardiovascular Magnetic Resonance Unit, The Royal Brompton Hospital, London, United Kingdom, 3National Heart and Lung Institute, Imperial College London, London, United Kingdom, 4Data Science Institute, Imperial College London, London, United Kingdom |
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To better understand diffusion MRI in biological tissues, numerical simulations are commonly used to model the MR signal. Realistic simulation substrates built directly from histology images help to reduce the model error, but intrinsic parameters other than the microstructure have an effect too. In this study, we investigate the relationship between diffusion tensor fractional anisotropy and membrane permeability. Using a GPU-accelerated Bloch–Torrey solver, we observe a significant difference from the impermeable case for long diffusion times on the order of 1s. |
| 3645 | Computer 139
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Comparison of Cylindrical and Spherical Geometric Models to Infer Cell Sizes in a Celery Sample |
1Physics, University of Winnipeg, Winnipeg, MB, Canada, 2Cubresa, Inc., Winnipeg, MB, Canada, 3Physics and Astronomy, University of Manitoba, Winnipeg, MB, Canada, 4Biology, University of Winnipeg, Winnipeg, MB, Canada |
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Temporal diffusion spectroscopy (TDS) can be used to infer sizes of cells in samples. It relies on a geometric model to relate the MRI signal to the cell sizes. Celery collenchyma tissue and vascular bundles have long cells while parenchyma cells are rounder. We compared a cylindrical and spherical geometric model in temporal diffusion spectroscopy to determine how important the geometrical model was for celery. The inferred diameters of cells in celery (14±6µm to 20±12µm) were not statistically different when using the two different geometric models. This is the first step toward understanding the importance of geometric models for TDS. |
| 3646 | Computer 140
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Kärger Model Difficulties for In Vivo DWI |
1Westview High School, Portland, OR, United States, 2Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 3Home, Mill Creek, WA, United States, 4Surgery, Oregon Health & Science University, Portland, OR, United States |
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Although it is well known that diffusion-weighted imaging (DWI) is sensitive to in vivo trans-membrane water-exchange, quantitative interpretation of the diffusion b-space decay remains difficult. Using random-walk simulated DWI data, this study investigates the feasibility and reliability in studying the water exchange effects with a multi-exponential fitting approach on DWI data. |
| 3647 | Computer 141
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Non-destructive measurement and prediction of soluble solids of fruits using diffusion-weighted magnetic resonance imaging |
1Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo, China, 2Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, The University of Nottingham, Nottingham, United Kingdom |
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Diffusion-weighted magnetic resonance imaging (DW-MRI) was used to measure and predict total soluble solids (TSS, unit: °Brix) of fruits noninvasively. The results demonstrated that mean apparent diffusion coefficient (ADC) in fruits was strongly correlated with TSS of fruit juice (R ≥ 0.92 and p ≤ 1.51E-4). DW-MRI shows great potential for future commercial implementation of fruit quality evaluation. |
| 3648 | Computer 142
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Diffusion Time Dependence of Diffusion Tensor Parameters in the Evaluation of Meningioma Subtype: a Preliminary Study |
1Radiology, Juntendo University Hospital, Tokyo, Japan, 2Radiology, The University of Tokyo Hospital, Tokyo, Japan, 3Siemens Healthcare Japan KK, Tokyo, Japan |
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We investigated the DTI eigenvalues and MD of five types of meningioma acquired with a shorter diffusion time using an OGSE sequence. Eleven meningiomas that consisted of 4 meningothelial meningiomas, 2 fibrous meningiomas, 2 transitional meningiomas, 1 psammomatous meningioma, and 2 atypical meningiomas were analyzed. Our results showed that the psammomatous and atypical meningiomas had a relatively strong diffusion time-dependence of diffusion tensor metrics. The use of shorter diffusion time with DTI provide additional information about the microstructure of each meningioma subtypes. |
| 3649 | Computer 143
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Whole-Tumor Histogram Analysis of Monoexponential and Advanced Diffusion-weighted Imaging for Sinonasal Malignant Tumors: Correlations with Histopathologic Features |
1Eye & ENT Hospital of Fudan University, Shanghai, China, 2Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 3Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 4Pathology, School of Basic Medical Sciences, Fudan University, Shanghai, China, 5Biostatistics, School of Public Health, Fudan University, Shanghai, China, 6MR Scientific Marketing, Siemens Healthcare, Shanghai, China |
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This is the first study with a large sample size to systematically investigate the correlation of monoexponential diffusion-weighted imaging (DWI) and advanced DWI (intravoxel incoherent motion [IVIM] and diffusion kurtosis imaging [DKI]) parameters with histopathologic features of sinonasal malignant tumors using whole-tumor histogram analysis, which could improve the interpretation of DWI findings and promote the use of these diffusion methods in clinical practice. In comparison with monoexponential DWI and biexponential DWI (IVIM), histogram metrics derived from DKI may better reflect the microstructure of sinonasal malignant tumors, including the cellular, stromal and nuclear fractions. |
| 3650 | Computer 144
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Examining Links Between Free Water and a TSPO-PET Marker of Neuroinflammation |
1Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Boston, MA, United States, 2Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 4Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 5Research and Development, VA Boston Healthcare System, Boston, MA, United States |
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Free-water (FW) is a diffusion MRI marker of freely diffusing water in the extracellular space, which is expected to increase in the presence of neuroinflammation. Here, we test associations between FW and positron emission tomography (PET) imaging of the translocator protein (TSPO), which is a putative neuroinflammatory marker. We show that increased FW relates to higher TSPO binding in the hippocampi of healthy controls, but not of individuals with sports-related, repetitive traumatic brain injury. Thus, while FW relates to TSPO under healthy conditions, pathological variance in TSPO may complicate associations between FW and TSPO-indexed neuroinflammation. |
| 3651 | Computer 145
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A Novel Metric Shows the Robustness of the Graph Communities to Brain-Tractography False-Positives. |
1Computer Science, Centro de Investigación en Matemáticas A.C., Guanajuato, Mexico, 2CONACYT-CentroGeo-CentroMet, Queretaro, Mexico |
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We study the impact of the brain tractography false positives in the brain connectivity graphs. The representative input database for the analysis is the set of tractograms from the participants on the ISMRM-2015 Tractography Challenge. We propose 2 novel metrics to rank the quality of a tractogram when it is compared with a known ground truth. The results of this study indicate that the the estimation of graph communities is robust to high levels of overestimation in the connectivity. |
| 3652 | Computer 146
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The multi-play of diffusion tensor imaging and immunohistochemistry to unveil the longitudinal microstructural brain alterations in a closed head brain injury model. |
1Queensland Brain institute, Brisbane, Australia, 2Adelaide Medical School, University of Adelaide, Adelaide, Australia, 3School of Health Sciences, University of South Australia, Adelaide, Australia |
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Traumatic brain injury (TBI) is a disease burden worldwide and it is associated with axonal injury and neuroinflammation. Investigating the underlying mechanisms and the progression in the acute and sub-acute stages following TBI non-invasively would aid for early diagnosis and intervention. In this study, we used diffusion tensor imaging (DTI) to investigate the microstructural changes following TBI. Furthermore, we used immunohistochemistry to investigate the axonal injury and microglial activity following TBI. Using DTI, we detected persistent microglial activity associated with TBI which might suggest a possible use of DTI for reflecting on the microstructural changes associated with TBI in humans. |
| 3653 | Computer 147
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How reproducible are the results of probabilistic white matter tract estimation? |
1Department of Biomedical Egineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Department of Neuroradiology, King's College Hospital, London, United Kingdom, 3Department of Medical Physics and Bioengineering, NHS Highland, Inverness, United Kingdom |
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Diffusion tractography and fMRI data is valuable for pre-surgical planning, but its analysis involves a number of user-dependent decisions. In particular the choice of activation threshold in fMRI maps and the definition of seed region in tractography may impact the results. This work evaluates both the intrinsic variability of probabilistic white matter tract estimation and the inter-user reproducibility of tractography analysis. The former was estimated from repeated identical processing, while for the latter tracts obtained by different users were compared. Achieving a good inter-user reproducibility (up to 85%) is possible, considering that the intrinsic reproducibility ranged between 72% and 89%. |
| 3654 | Computer 148
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Consistency and Reproducibility of Probabilistic Tractography |
1Imaging Institute, The Cleveland Clinic, Cleveland, OH, United States, 2Neurological Institute, The Cleveland Clinic, Cleveland, OH, United States |
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Deciding from among the many available tractography algorithms can be challenging. We demonstrate that track-based measures can be compared using standard statistical approaches to compare the performance of two probablistic tractography algoirthms to determine the conditions under which one algorithm can replace another. |
| 3655 | Computer 149
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Validation of Diffusion Imaging Measures in Gray Matter using Histology from macaque monkey |
1Graduate Program for Neuroscience, Boston University, Boston, MA, United States, 2Psychiatry NeuroImaging Lab, HMS, BWH, Boston, MA, United States, 3Harvard Center for Biological Imaging, Harvard University, Cambridge, MA, United States, 4Center for Morphometric Analysis, Massachusetts General Hospital, Charlestown, MA, United States, 5Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 6Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States |
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This study is the first attempt towards histological validation of diffusion imaging measure of Trace in the gray matter of macaque monkey. Heterogeneity of Trace (hTrace) computed for one monkey in 7 cytoarchitectonically different regions was compared with the variance in intracellular volume fraction for the same regions computed using digitized histological sections, stained for all cell bodies. hTrace was found to be significantly correlated with the variance in intracellular volume fraction. This shows that the diffusion measure of hTrace is sensitive to the underlying gray matter cytoarchitecture such as the cell size and cell packing density. |
| 3656 | Computer 150
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Free water mapping in diffusion MRI: How do two common approaches compare? |
1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States |
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Free water eliminated diffusion tensor imaging (fwDTI) and neurite orientation dispersion and density imaging (NODDI) are two increasingly established techniques that measure free water (FW) in diffusion MRI. Yet, despite the utility of each approach, their corresponding FW estimates have yet to be compared. In this work, we find that FW measurements near cerebrospinal fluid are highly similar between the two approaches, but within tissue, NODDI tends to compute slightly higher FW values in the white matter and lower FW values in gray matter than fwDTI. Potential sources of this discrepancy are discussed. |
| 3657 | Computer 151
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Value of patent foramen ovale in grey matter and white matter lesions of migraine: A comparative study |
1Department of Diagnostic Radiology, First Affiliated Hospital of Xi’an Jiaotong University, xi'an, China, 2Department of Neurology, First Affiliated Hospital of Xi’an Jiaotong University, xi'an, China |
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Migraine is a complicated neurological disability disease and still not been clarified. PFO may be a subset to cause migraine. Therefore, this study aims to analysis the value of PFO in grey matter and white matter lesions of migraine. We found that the changes mainly in frontal cortex, precentral gyrus regions of pain modulating area between patients with PFO and without PFO in migraine. However, out results do not support the relationship between PFO and white matter lesions. This findings may provide a new insight for clinical treat strategy. |
| 3658 | Computer 152
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A New Nodal Staging System for Nasopharyngeal Carcinoma Based on the Quantitation of Metastatic Lymph Nodes |
1radiology, Sun Yat-sen University Cancer Center, Guangzhou, China |
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We aimed to investigate whether the number of metastatic lymph nodes (LNs) is an independent prognostic factor for progression-free survival (PFS) in nasopharyngeal carcinoma (NPC) and to establish a new N staging system based on the number of positive LNs on magnetic resonance imaging. In 792 NPC patients, we found that the number of metastatic LNs was the only independent prognostic factor for PFS following multivariate analysis. We categorized the number of metastatic LNs into 4 groups to create a new N staging system which was more effective than the American Joint Committee on Cancer staging system for predicting PFS. |
| 3659 | Computer 153
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Accuracy of Synthetic MAgnetic Resonance image Compilation (MAGiC) neural scan |
1Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, 2GE Healthcare, Taipei, Taiwan, 3Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan |
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This study aimed to verify the accuracy of quantitative T1 and T2 estimation generated from a synthetic MR imaging method, MAGiC by comparing these results with conventional scanning on a homemade phantom with 9 concentration of aqueous CuSO4, and our result showed that the quantitative estimations were inaccurate in the CSF regions. In addition, the MAGiC synthetic image contrast was evaluated in both healthy volunteers and stroke patients. Agreed with the quantitative estimations, the CSF regions caused the apparent contrast differences. |
| 3660 | Computer 154
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Comparing the Quantitative T1 and T2 Mapping Acquired by Magnetic Resonance image Compilation (MAGiC) and MR Fingerprinting (MRF) |
1Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, 2GE Healthcare, Taipei, Taiwan, 3GE Healthcare MR Research China, Beijing, China, 4IMAGO7 Foundation, Pisa, Italy, 5National Institute for Nuclear Physics, Pisa, Italy, 6Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan |
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Quantifying tissue T1 and T2 provides valuable biomarker for characterizing various tissue pathologies yet limits by its long scan time and consequently hampered their clinical practice. Magnetic resonance image compilation (MAGiC) and Magnetic resonance fingerprinting (MRF) are novel imaging techniques that simultaneously provide quantitative maps of tissue relaxation times at one acquisition. We compared the quantitative values in various brain tissue using the MAGiC and MRF in healthy volunteers. In quantifying T1 between two techniques, no significant difference was found in white matter and gray matter, but difference was observed in cerebrospinal fluid. On the contrary, T2 value showed significant difference. |
| 3661 | Computer 155
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Clinical Implementation of Fast Markerless Motion Correction in K-Space of Structural 3D MR-Images of the Brain |
1DTU Compute, Technical University of Denmark, Lyngby, Denmark, 2Tracinnovations, Ballerup, Denmark, 3Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen, Denmark, 4CUBRIC School of Engineering, Cardiff University, Cardiff, United Kingdom |
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This work demonstrates retrospective motion correction using a markerless motion tracker to accommodate the needs in the clinical workflow. Motion degradation in neurological MRI imaging is a major concern and causes increased study time and cost due to repeated scans and the need for sedation or anesthesia. With retrospective motion correction of raw k-space data, both the corrected and non-corrected images can be reconstructed and presented for the radiologists within a few minutes. The external markerless motion tracker is sequence independent meaning that retrospective motion correction can be applied to clinical examination without sequence modification or added scan time. |
| 3662 | Computer 156
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Early evaluation of radiation-induced parotid damage in patients with nasopharyngeal carcinoma by T2 mapping and mDIXON Quant imaging: initial findings |
1Radiology, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China, 2Philips Healthcare, Shanghai, China |
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Forty-one patients with NPC underwent T2 mapping and mDIXON Quant imaging for parotid glands before RT, mid-RT, and post-RT. From pre-RT to mid-RT, parotid T2 and FF values increased significantly. From mid-RT to post-RT, parotid T2 value continuously increased, but parotid FF value decreased significantly. Change rate of parotid T2 value significantly correlated with parotid atrophy rate from pre-RT to post-RT. Parotid T2 value and FF value negatively correlated with parotid volume, while parotid T2 value positively correlated with MR scan time point significantly. T2 mapping and mDIXON Quant imaging is useful for noninvasive evaluation of radiation-induced parotid damage. |
| 3663 | Computer 157
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Functional stability of clinical research neurological scanners |
1Medical Physics Department, Bambino Gesù Children's Hospital, Rome, Italy, 2Neuroradiology Department, Carlo Besta Neurological Institute, Milan, Italy, 3Brain MRI 3T Center, Mondino National Neurological Institute, Pavia, Italy, 4IRCCS Stella Maris Foundation, Pisa, Italy, 5Imago7 Foundation, Pisa, Italy, 6Brain MRI 3T Research Center, Mondino National Neurological Institute, Pavia, Italy, 7Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 8Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 9Advanced Neuroimaging Network of Italian Research Neurological Institutes (IRCCS), Italy, Italy |
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A multicenter network of Italian Neurological Research Hospital was recently started. Its first aim was to establish quality assessment protocols for future quantitative imaging studies. In this context, we report the outcome of the first 6 months of data collection using a dedicated phantom and processing pipeline. Scanner performance was assessed in terms of several stability indicators, grouped by manufacturer. The preliminary results represent the initial step towards a large-scale scanner stability assessment in clinical settings. We expected to gather regular data from all the sites in order to broaden data analysis and assess the multi-site temporal stability. |
| 3664 | Computer 158
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Single-breath-hold whole-heart-coverage accelerated 3D-cine cardiac MRI |
1Medical College of Wisconsin, Milwaukee, WI, United States |
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Conventional cine imaging consumes a large part of scan time due to the need to acquire a stack of short-axis and long-axis slices. In this study, we provide preliminary results about the feasibility of a single-breath-hold whole-heart-coverage accelerated 3D-cine acquisition in a fraction of this time using recent developments in acquisition and reconstruction techniques. The results shows significantly reduction of scan time by more than 90%. Despite encountered reduction in resolutions, SNR and CNR, sufficient image quality was maintained such that the resulting clinical measurements were not significantly different from those obtained using conventional cine acquisition. |
| 3665 | Computer 159
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Hypovascular nodules detected on gadoxetic acid-enhanced MR imaging: Risk factors and appropriate treatments for hypervascular transformation |
1Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China., Beijing, China, 2Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, Beijing, China, 3GE Healthcare, MR Research China, Beijing, China, Beijing, China |
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Hypovascular hypointense nodules detected in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI have significant potential to transform into hypervascular hepatocellular carcinoma (HCC). This study aims to assess the risk factors for hypervascular transformation and to enable guiding the clinical treatment properly. |
| 3666 | Computer 160
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Evaluation the functional of parotid glands in diabetic patients: diffusion-weighted echo-planar MRI before and after stimulation |
1Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China, 2Graduate School of Hebei Medical University, Shijiazhuang, China, 3MR Scientific Marketing, Siemens Healthcare, Beijing, China |
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Recent studies have reported that lipid infiltration (LIPG) may be one of the mechanisms of salivary secretion decrease in diabetic patients. In this study, we compared the difference of ADCs between normal and patients before and after stimulation. It demonstrated that diffusion-weighted echo-planar MR imaging allows non-invasive quantification of functional changes in the parotid glands and the feasibility in reflecting the degree of fat deposition in parotid gland caused by parotid dysfunction. |
| 3667 | Computer 161
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Improving Patient Comfort by Shortening MR Scan Duration with the Help of Compressed SENSE |
1Philips Health Systems, Philips India Limited, Chennai, India, 2Deaprtment of Radiology, Fortis Memorial Research Institute, Gurugram, India, 3Philips Health Systems, Philips India Limited, Gurugram, India |
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Compressed SENSE i.e parallel imaging combined with Compressed Sensing, plays a vital role in reducing the overall imaging time without compromising the image quality. Objective of the study is to analyze the impact of using Compressed SENSE to improve the patient comfort by reducing the scan time. This is achieved by implementing Compressed SENSE in T1, T2, PD Weighted TSE, T1 & T2 FFE based sequences in 2D & 3D mode in routine MR Examinations. |
| 3668 | Computer 162
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Comprehensive comparison of MR image quality between intratympanic and intravenous gadolinium injection using 3D real IR sequences |
1Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 2Eye & ENT Hospital of Fudan University, Shanghai, China, 3Weifang People's Hospital, Weifang, China, 4Suzhou Municipal Hospital, Suzhou, China, 5Scientific Marketing, Siemens Healthcare Ltd, Shanghai, China, 6Scientific Marketing, Siemens Healthcare Ltd., Shanghai, China |
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Both intratympanic (IT-method) and intravenous (IV-method) administration of gadodiamide are used to detect endolymphatic hydrops. The purpose of our study was to comprehensively compare the image quality of the two methods. By qualitative and quantitative comparison, the IV-method can be used as an alternative to the IT-method in future clinical applications. |
| 3669 | Computer 163
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MRI prediction of Slipped Capital Femoral Epiphysis in children |
1Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China, 2Department of Radiology, Liaoning Electric Power Center Hospital, Shenyang, China, 3Philips Healthcare, Beijing, China, 4Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom |
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We compared the MRI images of peripheral skeletal muscle atrophy and steatosis between heathy children and children with Slipped Capital Femoral Epiphysis (SCFE). Statistical analysis revealed the correlation between the two pathological changes in MRI images and the incidence of SCFE,and get the threshold value of two indicators leading to the onset of SCFE,which holds potential for the guidance on clinical diagnosis and therapy plan for SCFE. |
| 3670 | Computer 164
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Enhanced Value and Diagnostic Utility in Musculoskeletal MRI Using ZTE |
1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States |
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Zero Echo Time (ZTE) MRI affords CT-like positive contrast visualization of bone This study highlights instances in which ZTE imaging proved clinically useful as an adjunct to standard-of-care MRI in diagnosis and treatment of musculoskeletal injuries. Cases are presented in which patient circumstances (pregnancy, age, prior imaging, etc.) coupled with the underlying pathology resulted in added diagnostic, safety, monetary, and/or temporal value for the patient or care team. This study coupled with our prior work indicates that ZTE imaging can provide a suitable alternative to CT and, in certain circumstances may in fact, be preferable. |
| 3671 | Computer 165
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The changes of R2’ in quantitative evaluation of acute renal injury: Preliminary animal study |
1Peking University, Beijing, China, 2Shanghai Jiao Tong University, Shanghai, China, 3Peking University First Hospital, Beijing, China |
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As a recently proposed novel pulse sequence, the pulse-shifting multi-echo asymmetric spin echo (psMASE) can isolate R2’ in real time. Combined with gas challenge, it can be used to evaluate acute renal injury (AKI) quantitatively. In this study, we further investigated the feasibility of the change of R2' value (dR2’) in distinguishing different severities of AKI using this sequence. Results suggested that there was significant difference between the different severities of AKI and dR2’, which indicating that the dR2' value can serve as a potential quantitative indicator for acute renal injury evaluation. |
| 3672 | Computer 166
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A test-retest multi-site reproducibility of neurovascular 4D flow MRI |
1MR, the First Affiliated Hospital of Zhengzhou University, zhengzhou, China, 2the First Affiliated Hospital of Zhengzhou University, zhengzhou, China, 3GE Healthcare, beijing, China |
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4D flow shows great potential in neurovascular disorders such as stenosis, atherosclerotic disease, aneurysms, and vascular malformations; its widespread application in neurovascular system requires evidence of good test-retest multi-site reproducibility. This study would like to assess the multi-center reproducibility, test-retest variability and inter-observer dependence of 4D flow MRI in neurovascular system. |
| 3673 | Computer 167
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3D CUBE MRI of facial nerve lesions in temporal bone: a preliminary study |
1Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China, 2Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China, 3GE Healthcare MR Research, Beijing, China |
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This study mainly investigated the feasibility of three-dimensional (3D) CUBE MRI for high resolution facial nerve imaging in patients with peripheral paralysis. We thus systematically measured the corresponding patients with three different syndromes using 3D fat suppressed CUBE technique. While significant image enhancement between the affected and unaffected sides was almost shown in all segments for the patients, different effects were found in mastoid and internal auditory canalicular regions，We thus can demonstrate the feasibility of 3D CUBE MRI in the diagnosis of patients with facial paralysis relevant diseases. |
| 3674 | Computer 168
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The prognostic value of detailed MRI reports in predicting the progress-free survival of patients with nasopharyngeal carcinoma |
1Department of Radiology, Sun Yat-sen University Cancer Center, Guangzhou, China |
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To evaluate the prognostic value of detailed MRI reports for progress-free survivals (PFS) of patients with Nasopharyngeal Carcinoma (NPC) who underwent intensity modulated radiation therapy (IMRT), we used Cox regression to analyze all the variables of detailed MRI reports and to build a new nomogram for PFS. Our results demonstrated that the new nomogram was more efficient than the American Joint Committee on Cancer (AJCC) 8th staging system. These results indicated that detailed MRI reports could play a more important role in predicting PFS, and some significant factors may be added to improve the current staging system. |
| 3675 | Computer 169
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3D T1-weighted Images with Scan Time of Less than 2 Minutes by Using Wave-CAIPI |
1Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan, 2Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan, 3Integrated Clinical Education Center, Kyoto University Hospital, Kyoto, Japan, 4Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 5Siemens Healthineers, San Francisco, CA, United States, 6Siemens Healthineers, Erlangen, Germany |
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A preliminary imaging study for MPRAGE with Wave-CAIPI has been introduced at the clinical MR scanner. MPRAGE with Wave-CAIPI 3×3 shows relatively better contrast despite its short scan time. Less imaging noise and segmentation error was found in MPRAGE with Wave-CAIPI 3×3. MPRAGE with GRAPPA 3×3 showed prominent imaging noise and segmentation errors, however, MPRAGE with CAIPI 3×3 showed few segmentation errors and almost equivalent to Wave-CAIPI 3×3. |
| 3676 | Computer 170
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Decreased Relative Cerebral Blood Flow In Unmedicated Heroin Use Disorders |
1Department of Radiology, Second Xiangya Hospital of Central South University, Changsha, China, 2Department, Hunan Judicial Police Academy, Changsha, China |
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Sixty-eight patients with heroin use disorders(HUD) and forty-seven matched healthy controls underwent a high resolution T1 and whole-brain pulse arterial spin labeled (PASL) perfusion magnetic resonanceMRI scanning. We found that compared to control subjects, HUD showed worse neuropsychological performance and significantly decreased regional relative CBF (（rCBF）) in HUD patients had hypoperfusion in limbic, frontal, and temporol areas,and the correlation between middle frontal gyrus(MFG) and theneurocognitive measures. |
| 3677 | Computer 171
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Energy usage of a newly operational GE Healthcare Signa Premier 3T MRI |
1Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Sustainability, University of California, San Francisco, San Francisco, CA, United States |
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Healthcare is a leading producer of carbon emissions with radiology as a key contributor. Our study describes the GE Premier's energy consumption. When operational for 10 hours in a 24 hour day, the GE Premier consumed 57.69 kwh, which is over double the energy consumption of the average household. Individual scans require 2.44-4.98 kwh; refrigerators use 1-2 kwh a day. Ready-to-scan and scanning modes require 4-10x the power of off mode. Optimizing the use of off mode will yield energy savings, and comparison to other models may guide environmentally conscious expansion of radiology services. |
| 3678 | Computer 172
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Let’s play! The MR escape room |
1University Medical Center Utrecht, Utrecht, Netherlands, 2Utrecht University, Utrecht, Netherlands |
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To create an innovative teaching method that engages students new to MR. The MR Escape room is a fun game that tests the (newly acquired) knowledge of students, while doubling as a team building exercise. |
| 3679 | Computer 173
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A Dedicated Head-Only MRI Scanner for Point-of-Care Imaging |
1Synaptive Medical, Toronto, ON, Canada, 2Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada, 3Department of Medical Biophysics, Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada |
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A dedicated head-specific MRI is presented. The MRI is designed to address many of the siting and installation requirements to better allow the use of MRI in point-of-care imaging. |
| 3680 | Computer 174
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HCC screening with abbreviated MRI: retrospective comparison of noncontrast, dynamic-contrast enhanced and hepatobiliary phase protocols post gadoxetic acid |
1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Columbia University, New York, NY, United States, 5Radiology, Albert Einstein College of Medicine, New York, NY, United States, 6Infectious diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 7Radiology, UC San Diego Medical Center, San Diego, CA, United States |
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In this study, we compare the performance of different abbreviated MRI (AMRI) protocols using 3 different sets: noncontrast, dynamic T1WI, and hepatobiliary phase (HBP) post gadoxetic acid for hepatocellular carcinoma (HCC) screening in 238 patients at risk. Our results showed that performance of noncontrast AMRI was low, while AMRI using dynamic T1WI and AMRI including HBP showed equivalent sensitivity for HCC detection with slightly better specificity for dynamic T1W. These results need verification in a larger study. |
| 3681 | Computer 1
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Sex-linked neurofunctionnal basis of psychological resilience in late adolescence |
1Huaxi MR Research Center, West China Hospital, Sichuan University, Chengdu, China |
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Psychological resilience refers to the ability to bounce back from adversity and previous studies have shown sex differences in psychological resilience. Here, we employed amplitude of low-frequency fluctuations (ALFF) to investigate sex differences in the relationship between resting-state brain activity and psychological resilience in 231 healthy adolescents. Behaviorally, we found that males were more resilient than females. Neurally, a positive correlation between psychological resilience and the ALFF in the right orbitofrontal cortex was detected among males while a negative correlation was observed among females. Together, our study provided the first evidence of sex-specific neurofunctional substrates underlining psychological resilience in adolescents. |
| 3682 | Computer 2
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Gender differences in the relationship between gray matter structure and psychological resilience in late adolescence |
1Huaxi MR Research Center, West China Hospital, Sichuan University, Chengdu, China |
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Although behavioral studies have shown that males are more resilient than females, the effects of gender on the relationship between brain structure and psychological resilience are largely unknown. Here, we investigated the gender-specific associations between psychological resilience and regional gray matter volume (GMV) in 231 healthy adolescents via structural magnetic resonance imaging. We found that the relationship between psychological resilience and GMV differed between genders in the left ventrolateral prefrontal cortex, with a positive correlation in males and a negative correlation in females. Therefore, our study provided the first evidence for the gender-specific neuroanatomical correlates of psychological resilience. |
| 3683 | Computer 3
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Effects of Omega-3 Fatty Acids on Brain Connectivity in Long-Evans Rats |
1Imaging Research Center, Department of Radiology, Cincinnati Children's, Cinicinnati, OH, United States, 2Pediatric Neuroimaging Research Consortium, Cincinnati Children's, Cinicinnati, OH, United States, 3UC Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States |
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This study examines the impact of dietary fatty acid intake on functional connectivity of the maturing brain. This study was performed with 88 rats. In vivo as well as ex vivo neurological data was collected by means of MR imaging and postmortem gas chromatography. The graphs were compared by using network-based statistics and showed non-significant trends between the controls and the fatty-acids deficient group. Network metrics were also computed and showed non-significant trends between the controls and the fatty acids deficient group. |
| 3684 | Computer 4
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Stress and the brain: Perceived stress mediates the impact of the superior frontal gyrus spontaneous activity on depression in late adolescence |
1Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China |
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Perceived stress (PS), which reflects the tendency to appraise one’s life situations as stressful and overwhelmed, is a stable predictor for depression. Here, we used resting-state functional magnetic resonance imaging to investigate the neural basis of PS and the underlying brain mechanism linking PS and depression in 217 adolescents. We found that PS was positively related to the spontaneous activity in the left superior frontal gyrus (SFG). Furthermore, PS mediated the link between the left SFG activity and depression. Altogether, our study might present a neurofunctional marker of PS and reveal an underlying brain-stress mechanism for predicting depression. |
| 3685 | Computer 5
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Odor stimulation by automated syringe pumps in combination with the independent component analysis for BOLD-fMRI study of mouse whole brain |
1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan |
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Olfactory perception in mice involves the activation of brain regions. We previously developed a method that uses repetitive odor stimulation and independent component analysis (ICA) for BOLD-fMRI studies. Using BOLD-ICA, we sought to detect odor-evoked responses in the mouse whole brain. Previously, the administration of an odorant substance had been performed by manually operating a syringe pump to infuse the saturated vapor of an odorant substance. We constructed a system that automatically controls the syringe pump, to ensure the accuracy of stimulation timing and duration. We demonstrate the improved detectability in the BOLD-ICA method by the automated system. |
| 3686 | Computer 6
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Structural and Resting-State Functional Connectivity Changes of the MPS I Mouse Brain |
1Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 2Department of Biomedical Engineering, Penn State University, State College, PA, United States, 3Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 4College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States |
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Mucopolysaccharidoses (MPSs) is a group of inherited lysosomal storage disorders that could cause multiple organ failure, cognitive impairment, and shortened life span. In spite of the recognizable clinical morphological and physiological features associated with MPSs, brain connectivity changes and physiopathologic mechanisms responsible for these alterations in the central nervous system are rarely studied but might be a reliable biomarker for disease severity and treatment efficacy. A new study of brain connectome on MPS I mouse model using resting-state functional MRI (rs-fMRI) technique was conducted and a dramatic deterioration on functional connections involving multiple brain regions were observed. |
| 3687 | Computer 7
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BOLD-fMRI evaluation of analgesic candidates with different analgesic mechanisms against allodynia-specific pain in a chronic pain animal model |
1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan |
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The aim of this study is to evaluate the pain-relieving effect of a novel chemokine signal-inhibiting compound on allodynia-specific responses in a chronic pain animal model, using our BOLD-fMRI-based pain evaluation system with a green laser. We observed activations in four brain regions related to pain. We found that the compound suppresses green laser-evoked allodynia-specific responses in three regions. We expect that the compound has synergistic pain-relieving effects with existing analgesic agents. Our system is useful to evaluate the effects of new analgesic candidates in non-clinical and, expectantly, clinical studies. |
| 3688 | Computer 8
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Altered bilateral functional connectivity in rat brain under isoflurane and medetomidine anesthesia |
1CIBM-AIT, École polytechnique fédérale de Lausanne, Lausanne, Switzerland |
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Anesthetic agents are commonly used in rodent resting-state functional MRI. When anesthetized under different agents, brain functional connectivity can be altered. It has been shown that after isoflurane initiation, brain connectivity measured under medetomidine was extensively affected in a time-dependent manner. Here, we further compare the difference of resting-state networks detected under isoflurane and medetomidine anesthesia. |
| 3689 | Computer 9
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An awake mouse MRI method using mouse clothes for fMRI applications |
1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan, 2Bruker Japan K.K., Yokohama, Japan |
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In current awake MRI methods, fixing apparatuses implanted in the brain by surgery and acclimation procedures by training have been explored, to suppress head movement in the scanner. Previously, we reported an awake MRI method using mouse clothes designed for a cryogenic coil system, without surgery and training. We now report the successful optimization of the awake mouse MRI method for fMRI applications, using the newly designed mouse clothes. Resting-state analyses showed bilateral functional connectivities in the cortical and limbic system networks in an awake mouse. Our method will contribute to the acquisition of awake-specific neuronal responses. |
| 3690 | Computer 10
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Awake Macaque MRI Setup on 7T Human Scanner Platform for High-Resolution Anatomical and Functional Imaging |
1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2School of Medicine, Zhejiang University, Hangzhou, China, 3MR Collaboration Northeast Asia, Siemens Healthcare, Hangzhou, China |
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We introduced a customized setup for awake sitting macaque MRI in a 7T horizontal-bore human scanner. Considerations in the specialized design of monkey cage and head fixation device consisting of 1) monkey comfort in a Sphinx position, 2) stable head fixation, 3) easy mounting of the surface array for cortex imaging, and 4) easy presentation of visual stimuli. Our findings demonstrate that, in a well-trained awake monkey, with the increased contrast sensitivity and substantial gains in spatial resolution offered by ultra-high field MRI and a custom-made dense RF array, our setup is capable of achieving improved SNR and high time efficiency. |
| 3691 | Computer 11
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Are fMRI measurements in medetomidine-anesthetized rats temporally stable? |
1Functional Imaging Laboratory, German Primate Center, Göttingen, Germany, 2Georg-August University of Göttingen, Göttingen, Germany |
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Medetomidine is often used to anesthetize rats during BOLD fMRI, yet the exact protocols for its administration differ across studies, compromising comparability and raising questions regarding the stability of fMRI measurements over several hours of anesthesia. We performed multiple repeated measurements of somatosensory and resting-state fMRI in medetomidine-anesthetized rats for up to six hours. Four different protocols of medetomidine administration were tested for their capacity to sustain stable measures of stimulus-evoked response and functional connectivity. The reported results are expected to help researchers in choosing the administration regime best suited for their needs. |
| 3692 | Computer 12
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Neurological, Physiological, and Behavioral Effects Following Acute Cannabis Nose-Only Exposure in C57BL/6J Mice |
1Bioengineering, Northeastern University, Boston, MA, United States, 2Center for Translational Neuroimaging, Northeastern University, Boston, MA, United States, 3Psychology, Northeastern University, Boston, MA, United States |
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Cannabis use is rising worldwide. Robust standardized methodologies in animal models are needed to further elucidate the impact of cannabis on overall health. Our aim was to identify acute exposure methods that provide a viable model for human cannabis consumption. C57BL/6J mice were exposed to cannabis aerosols using a Volcano® vaporizing device. Cannabis dosage levels were identified that elicited a human-like response. Animals were exposed while undergoing fMRI scans of their neurological activity. BOLD data, coupled with blood pressure and behavioral tests, demonstrated that our exposure methods generated a reproducible response that can be adapted for further studies. |
| 3693 | Computer 13
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Examining fMRI time-series Multi-Scale Entropy as a Biomarker for Excitation/Inhibition Balance in the Brain |
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, 2Yerkes National Primate Center, Emory University, Atlanta, GA, United States |
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The maintenance of a dynamic balance between excitatory and inhibitory synapses in the neocortex is critical for brain function. Many psychiatric disorders are characterized by disturbance of E/I balance. In this study we examined the potential of the fMRI time-series complexity metric multi-scale entropy (MSE) to act as a biomarker for E/I balance, using a non-human primate (NHP) model. We disturbed the E/I balance with the sub-anesthetic ketamine, which induces disinhibition of projection neurons, especially in prefrontal cortex (PFC) during fMRI of conscious NHPs. Our results confirmed that fMRI MSE is a sensitive marker for E/I balance in the brain. |
| 3694 | Computer 14
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Tuning Neuromodulation Effects by Orientation Selective Deep Brain Stimulation in the Rat Medial Frontal Cortex |
1Center Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2First Department of Neurology, Faculty of Medicine, Masaryk University and St. Anne’s Teaching Hospital, Brno, Czech Republic, 3A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 4Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, 5Division of Biostatistics, University of Minnesota, Minneapolis, MN, United States, 6Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States |
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With simultaneous fMRI and Deep Brain Stimulation (DBS), we demonstrate modulation of activity in rat amygdala by using axon Orientation Selective Stimulation (OSS) DBS in rat infralimbic cortex, a homologue brain region for treating depression in humans. Our results demonstrate orientation selectivity based on number of activated pixels especially in the amygdala, though qualitatively also other brain areas showed modulation based on stimulation angle. OSS may add a new level of optimization for treating major depression disorders. |
| 3695 | Computer 15
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Sound-evoked functional magnetic resonance imaging of tinnitus and hyperacusis neural mechanisms |
1Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, 2Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, United States, 3Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong |
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Tinnitus involves the perception of sound in the absence of external acoustic stimuli. The underlying mechanisms of tinnitus have been investigated using noninvasive, whole brain functional imaging methods. However, the changes in the subcortical auditory system are less well understood. To address this knowledge gap, we conduct an auditory fMRI on a well-established sodium salicylate-induced rodent tinnitus and hyperacusis model. The results reveal frequency-dependent changes in auditory subcortical structures, inferior colliculus and lateral lemniscus by salicylate induced tinnitus. This study has advanced our understanding of subcortical auditory processing during tinnitus/hyperacusis and advances the rat model for further fMRI investigations. |
| 3696 | Computer 16
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Reduced brain functional connectivity induced by generalized pain identified by mice Rs-fMRI |
1Department of Psychiatry, Mcgill University, Montreal, QC, Canada, 2Department of Pharmacology and Therapeutic Innovation, Nagasaki University Institute of Biomedical Sciences Nagasaki, Nagasaki, Japan, 3Department Neurology & Neurosurgery, Mcgill University, Montreal, QC, Canada |
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Fibromyalgia (FM) is a disorder characterized by generalized pain. The acid saline-induced muscle (ASM) model is considered an acceptable animal model of FM with widespread chronic pain. Here, we investigated the impact of FM-like pain on neural communication, using the ASM model with non-invasive mouse resting state fMRI. We found that generalized pain reduces functional connectivity at the level of periaqueductal gray and retrosplenial cortex, two regions related to pain processing and FM. Moreover, we found a positive correlation between pain sensitivity measured by Von Frey test and the intensity of FC reduction at individual subject level. |
| 3697 | Computer 17
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Comparisons of resting-state networks obtained at 3 and 7 Tesla MRI in anesthetized rhesus monkey |
1Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of, 2Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, 3School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, 4Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of |
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Understanding resting-state fMRI (rsfMRI) is an important issue to identify the functional principles of the normal and pathological brain networks. Despite the importance in comprehending network as a whole, a deeper understanding of the resting-state networks is limited due to the lack of a proper animal model. Here, we used anesthetized non-human primate (NHP) for understanding rsfMRI networks commonly detected in humans. BOLD and MION-enhanced CBV rsfMRI networks were obtained at 3T and 7T. Stable eight cortical networks were observed from MION experiments at 3T and 7T, and similar networks were also detected from 7T BOLD due to enhanced sensitivity. |
| 3698 | Computer 18
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Signal changes in functional diffusion measurements in rats are not caused by tissue heating, but have a vascular contribution |
1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany |
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Functional diffusion MRI has been proposed as an alternative to BOLD fMRI, to offer a more direct read-out of neuronal activation. One aspect of the controversial discussion around functional diffusion is whether these signals follow the neuronal activation more closely. We performed BOLD and diffusion measurements with 250 ms temporal resolution upon sensory stimulation and found similar temporal evolutions for BOLD and diffusion signals. Specifically, both signals slowly returned to baseline after the stimulus. However, diffusion measurements with b=500 showed an earlier onset. We performed heat application to rule out tissue heating as a contribution to functional diffusion signals. |
| 3699 | Computer 19
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Effects of Isoflurane on Brain Functional Connectivity in Common Marmosets |
1Department of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, 2Regenerative medicine, The Jikei University School of Medicine, Tokyo, Japan, 3Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Wako, Japan, 4Department of Radiological Sciences, Human Health Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 5Veterinary Surgery Laboratory, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan |
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We examined the effects of isoflurane on brain functional connectivity in common marmosets using resting-state fMRI. We found that the thalamus was closely related to the mechanism of action of anesthesia and the default mode network (DMN), which is thought to function at rest. Isoflurane exhibited similar effect on the thalamus and human DMN region in humans but partly different effect onthe marmoset DMN region.In the future, we need to perform further investigations in detail by increasing the amount of data and reviewing analysis methods. |
| 3700 | Computer 20
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Identification and Characterization of Resting State Networks in the Translational Pig Model |
1Physics and Astronomy, University of Georgia, Athens, GA, United States, 2Bio-Imaging Research Center, University of Georgia, Athens, GA, United States, 3University of Georgia, Athens, GA, United States, 4Foods and Nutrition, University of Georgia, Athens, GA, United States, 5Animal and Dairy Science, University of Georgia, Athens, GA, United States |
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Due to the similar size, structure, composition, and neurodevelopment of the pig brain in comparison to the human brain, the pig serves as a valuable large animal model for studying brain connectivity. Presented here are five resting state networks (RSNs) identified within the three-week-old piglet brain determined using temporal sparse dictionary learning. Each RSN’s learned activation map correlates well with a constructed pig RSN atlas with Pearson spatial correlation coefficients in the range of [0.30 0.53], and clear differences in the power spectra, as well as unique characteristic frequencies, associated with the learned signal for each RSN are observed. |
| 3701 | Computer 21
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Creation and evaluation of a generic rat hemodynamic response function for analysis of BOLD fMRI measurements |
1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany |
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For a reliable analysis of BOLD fMRI data, a suitable model of the hemodynamic response is essential. Therefore, an accurate model of the BOLD response of small animals is required in preclinical studies. Commonly used analysis tools like SPM or BrainVoyager have implemented HRFs optimized for humans by default. Since the BOLD responses of rats proceed faster than those of humans, we have determined a generic rat HRF based on 98 BOLD measurements of 35 rats which can be used for statistical parametric mapping. Statistical analysis of rat data showed a significantly improved detection performance using this rat HRF. |
| 3702 | Computer 22
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The Effect of IC Number Selection in Group ICA for Rat Functional Connectivity |
1School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 2Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan, 3Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, 4Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, 5Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan, 6Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 7Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan |
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Optimal IC number used in the ICA has been a kernel issue for functional MRI (fMRI) analysis. Nevertheless, |
| 3703 | Computer 23
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Network structure of the mouse brain connectome with voxel resolution |
1Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy, 2Functional Neuroimaging Laboratory, Center for Neuroscience and Cognitive Systems @ UniTn, Istituto Italiano di Tecnologia (IIT), Rovereto, Italy, 3Multimodal Imaging and Connectome Analysis Lab, Montreal Neurological Institute, McGill University, Montreal, QC, Canada |
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We provide a fine-grained description of the network structure and topology of the mouse connectome with voxel-resolution. We show that structural connectivity hubs can be spatially segregated into a dichotomic set of neural sink and neural source regions, and that functional and structural hubs show concordant neuro-anatomical topography. We finally demonstrate that the modular structure of the mouse connectome recapitulates large-scale fMRI networks of the mouse brain, including a default mode network core community, which is characterized by high structural resilience. Our results lay the foundation for topologically-driven targeted manipulations of the mouse connectome. |
| 3704 | Computer 24
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Sympathetic Contribution in Somatosensory Mouse fMRI: Revealing "Hidden" Key Structure Activations by Detailing Functional Response Dynamics |
1Berlin Ultrahigh Field Facility, Max-Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 2Max-Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 3DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany, 4Experimental and Clinical Research Center, A Joint Cooperation Between the Charite Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany |
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Electrostimulation of the paw is considered a basic paradigm to produce a reliable somatosensory response in animal fMRI. Yet, there is disagreement over the murine BOLD response: based on the anesthetic protocol either unilateral or bilateral patterns were reported. We hypothesize sympathetic activity as an origin of bilateral patterns, which is likely to be suppressed in protocols that employ α2-adrenoreceptor agonists. Utilizing finite impulse response (FIR) basis set modeling we present preliminary data that reveals "hidden" activity of brain structures which are known driving forces of sympathetic pathways. Our overall aim is to reveal the underlying mechanisms of this complex response to a simple paradigm and its implications for somatosensory mouse fMRI. |
| 3705 | Computer 26
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Normal variations in brain oxygen extraction fraction (OEF) are partly attributed to differences in end-tidal CO2 |
1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Quantitative assessment of brain oxygen extraction fraction (OEF) is of substantial clinical significance in many brain diseases. However, a remaining issue associated with OEF is its considerable inter-subject variations within healthy population. Therefore, it is important to investigate the physiological underpinnings of OEF variations among normal subjects. The present work used two studies, a discovery study and a verification study, to examine the extent to which end-tidal CO2 (EtCO2) can explain inter-subject variations in OEF. It was found that, across subjects, OEF is inversely correlated with EtCO2, and EtCO2 alone can account for about 50% of variances in OEF. |
| 3706 | Computer 27
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Whole-brain OEF quantification: a comparison study between QSM and dual-gas calibrated BOLD |
1McConnell Brain Imaging Centre and Department of Biomedical Engineering, McGill University, Montreal, QC, Canada, 2Hotchkiss Brain Institute and Department of Radiology, University of Calgary, Calgary, AB, Canada, 3Department of Biomedical Engineering, Cornell University, Ithaca, NY, United States, 4Department of Radiology, Weill Cornell Medical College, New York, NY, United States |
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The microvascular QSM approach for quantifying baseline brain oxygen metabolism has great potential due to its simple set-up and high spatial resolution. In this study, we aim to investigate the feasibility of the high SNR microvascular QSM-OEF technique with a hypercapnia gas challenge and compare OEF and CMRO2 measured by QSM-OEF with those measured using the dual-gas calibrated BOLD technique (DGC-BOLD-OEF), a reference standard. Baseline OEF and CMRO2 measured by hypercapnia QSM-OEF were found within the expected normal range for healthy subjects. Statistically significant but relatively small differences (5% difference) of OEF and CMRO2 were found between QSM-OEF and DGC-BOLD-OEF techniques. |
| 3707 | Computer 28
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The correlation between cerebral venous oxygen saturation change and cognitive score in Alzheimer's disease patients by using susceptibility weighted imaging mapping |
1Department of Radiology, First Affiliated Hospital of Dalian Medical University, Dalian,116011,China, Dalian, China, 2GE Healthcare, Beijing, China |
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Alzheimer's disease (AD) is a progressive neurodegenerative disease and vascular factors may be important in the development and progression of AD[1]. Magnetic susceptibility weighted imaging (SWI) is widely used in the diagnosis of central nervous system diseases, and venous oxygen content is the basis of SWI angiography. The venous blood oxygen level can be reflected by measuring the phase value of venous blood. This study first made use of SWI mapping (SWIM) to measure the change of magnetic susceptibility and the change of blood oxygen and then explores the correlation between cerebral venous oxygen saturation change and cognitive score in AD patients |
| 3708 | Computer 29
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Hypercapnic Normalization to Correct for Caffeine-Induced Changes in Task-Based BOLD fMRI Responses |
1Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada |
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This repeated-measures study sought to determine whether hypercapnic normalization can be used to address caffeine-induced vascular changes affecting BOLD responses. Visual/motor BOLD activation and cerebrovascular reactivity (CVR) under caffeine and placebo conditions were examined. CVR-correction was performed by dividing the task BOLD signal by CVR. Prior to CVR-correction, peak BOLD responses for both caffeine and placebo conditions were found in the visual cortex. After CVR-correction, peak responses were in the subcortical regions. Caffeine produced larger responses in the cerebellum compared to placebo, while subcortical activation was larger under placebo conditions. These results show that CVR-correction may benefit subcortical signal detection. |
| 3709 | Computer 30
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The temporal stability of BOLD is improved by calibrating the cerebral vascular reactivity underpinned by the vascular probability within the group |
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2Department of Medical Imaging, Taipei Medical University - Shuang-Ho Hospital, New Taipei, Taiwan, 3Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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We hypothesize that the local venule vasculature underlies the BOLD signal latency and its variability. This hypothesis was tested by measuring the BOLD signal in the human primary visual cortex with a 10-Hz sampling rate during a visuomotor and a breath-holding (BH) task. A venule probability (VP) map was estimated by susceptibility-weighted images. We found that VP was significantly correlated to the relative BOLD latency and relative latency variability during the visuomotor task. These correlations disappeared after subtracting the latency in the BH task from the latency in the visuomotor task. These results support our hypothesis. |
| 3710 | Computer 31
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The neurovascular response is attenuated by focused ultrasound-mediated disruption of the blood-brain barrier |
1Brigham and Women's Hospital, Boston, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Boston Children's Hospital, Boston, MA, United States |
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Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is a promising technology for achieving targeted delivery of pharmacological agents into the brain. While the method has been shown to be safe from the standpoint of not damaging tissue cells, it causes other changes to local physiology that are not fully understood. This study aims to characterize the effects on the hemodynamic response that FUS BBB opening causes. We present BOLD and CBF fMRI results to investigate the particular mechanisms within the neurovascular response responsible for this effect. |
| 3711 | Computer 32
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Increased Blood-Brain Barrier Water Permeability in the Visual Cortex in Response to Visual Stimulation |
1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Radiology, Stony Brook University, Stony Brook, NY, United States |
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Evidence of cell swelling upon activation has been observed in early diffusion functional MRI studies, and has been attributed to the co-transported water due to transient changes in ionic transmembrane flux. Blood-brain barrier (BBB) water permeability is also believed to be a marker of cerebral metabolism. Here we provide an initial investigation of visual stimulation on BBB water permeability parameters, water extraction fraction (Ew) and permeability surface area product (PSw), using the recently developed Intrinsic Diffusivity Encoding of Arterial Labeled Spins (IDEALS). Significant increase of PSw were observed with no change of Ew in the visual cortex during visual stimulation. |
| 3712 | Computer 33
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Improved sensitivity for detecting functional CBF changes by center-out EPI with very short echo time |
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany |
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Compared to BOLD imaging, the detection of functional CBF changes by arterial spin labeling is difficult due to the inherently small signal changes in the range of one percent or less. We compared a multi-echo EPI readout to center-out EPI that achieves a very short TE. The reduction of the minimum TE from 9.3 ms (multi-echo EPI) to a value of 1.8 ms (center-out EPI) yielded significantly improved statistical power in the human visual cortex in addition to diminished confounding BOLD and physiological noise contributions. |
| 3713 | Computer 34
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Measurements and modeling of the negative hemodynamic response function in human early visual cortex |
1Neuroscience, Baylor College of Medicine, Houston, TX, United States |
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A negative BOLD response is often observed in early visual cortex. Previous measurements indicate that negative BOLD is the consequence of flow decreases. However, negative BOLD is usually evoked by blocked experimental designs that obscure details of their temporal dynamics. To understand the physiology of the negative BOLD, we used a slow event-related paradigm to elicit strong hemodynamic response functions (HRFs) in primary visual cortex as a function of eccentricity. We used a modified version of the Arterial Impulse Model to predict the neurovascular and neurometabolic mechanisms of negative BOLD. Results indicate that negative BOLD physiology is profoundly different than positive BOLD with greater non-linearity. |
| 3714 | Computer 35
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Quantifying and Correcting for the Assumptions of the Static Dephasing Regime in Quantitative BOLD |
1Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom, 2Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 3School of Life Sciences, University of Nottingham, Nottingham, United Kingdom |
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The effect of diffusion is believed to cause underestimation of oxygen extraction fraction (OEF) in streamlined quantitative BOLD (qBOLD). We propose physically motivated modifications to the qBOLD model in order to account for this effect, and demonstrate, using Monte Carlo simulations, and analysis of healthy in vivo data, that simple scalar corrections to the inferred reversible relaxation rate $$$R_2'$$$, can substantially reduce the error in OEF and deoxygenated blood volume (DBV) estimation. These corrections have the potential to be improved further by taking other physiological and acquisition-related parameters into account. |
| 3715 | Computer 36
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Quantification of draining vein dominance across cortical depths in BOLD fMRI from first principles using realistic Vascular Anatomical Networks |
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, MA, United States, 4Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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The neuronal specificity of gradient echo (GE) BOLD is diminished by the extravascular signal from large draining veins, whose contribution can be reduced by using small voxel sizes and sampling far away from the cortical surfaced. Here we use simulations of the GE-BOLD signal based on a realistic vascular network (VAN) to quantify the extent of the pial vein dominance into the cortex field strengths between 7 and 14 Tesla. We estimate a pial vessel dominance down to a depth of 800 μm at 14 Tesla in humans, suggesting that small GE-BOLD voxels below this depth can be immune to the effects of these surface vessels. |
| 3716 | Computer 37
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A frequency-domain machine learning (FML) method for dual-calibrated estimation of oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen metabolism (CMRO2) |
1Cardiff University, Cardiff, United Kingdom, 2Concordia University, Montreal, QC, Canada |
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A frequency-domain machine learning method is presented that significantly reduces the bias and variance in dual-calibrated estimation of oxygen extraction fraction, as demonstrated with simulation and in-vivo imaging. In addition, the method substantially reduces the processing time compared to previous robust analysis methods. |
| 3717 | Computer 38
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fMRI investigation of the role of interhemispheric interactions in cortical sensory processing |
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China |
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Effective sensory communications require massive interconnected interhemispheric cortico-cortical projections. However, little is known at present regarding the exact interactions that occur bilaterally between sensory cortices across the brain hemispheres and how they influence cortical processing. Here, we employ optogenetic stimulation of the whisker-related thalamic excitatory neurons in combination with the somatosensory forepaw stimulation. We demonstrate a novel platform to investigate the interhemispheric interactions underlying cortical sensory processing. |
| 3718 | Computer 39
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Elevated activation of a murine limbic network during cue-reward association learning revealed in 15.2 T fMRI |
1Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan, 2Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of |
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An operant learning device for head-fixed mouse was developed for ultra-high field (15.2 Tesla) fMRI. Habituated mice were learned to water reward, associated with cue of light stimulation as a conditioning stimulus. We obtained 1,000 sets of BOLD fMRI (GE-EPI, TR/TE = 1000/11 ms), and found that elevated activation of a limbic learning network, including the entorhinal, perirhinal, and retrosprenial cortices and the hippocampal formation, during cue-reward association in learned mice. |
| 3719 | Computer 40
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Sympathetic contribution of respiratory effects to the fMRI signal |
1NINDS, NIH, Bethesda, MD, United States, 2Vanderbilt University, Nashville, TN, United States |
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fMRI signal covariation with fluctuations in systemic physiology, including cardiac rate and respiration, is well established. Recent work showed strong correlations between peripheral vascular tone, a proxy for sympathetic activity, and fMRI global signal during drowsiness and sleep. As sympathetic activity may also be triggered by inspiration, even during the alert waking condition typical of task fMRI, we investigated the relationship between respiration, peripheral vascular tone, and fMRI signal during a visual task. |
| 3720 | Computer 41
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Cerebrovascular Reactivity (CVR) mapping using intermittent breath modulation |
1Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Cerebrovascular reactivity (CVR) mapping is typically performed using CO2-inhalation or breath-holding as a vasoactive challenge while collecting BOLD images. Recently, resting-state BOLD has been used to map CVR by utilizing spontaneous fluctuations in breathing pattern, but the results could be noisy in subjects with little fluctuation in their spontaneous breathing. Here we developed a new technique for CVR mapping that does not require gas-inhalation yet provides substantially higher sensitivity than resting-state CVR mapping. This new technique is largely based on resting-state scan, but introduces intermittent modulation of breathing pattern in the subjects to enhance fluctuations in their end-tidal CO2 level. |
| 3721 | Computer 42
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Breath-hold BOLD-fMRI cerebrovascular reactivity metrics predict cognitive impairment in cerebral small vessel disease |
1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico – Universidade de Lisboa, Lisboa, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisboa, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal, 5Imaging Department, Hospital da Luz, Lisboa, Portugal |
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Cerebral small vessel disease (SVD) is associated with an increased risk of stroke and dementia, being implicated in age-related cognitive decline. In this work, we investigate the potential of cerebrovascular reactivity (CVR) to provide sensitive biomarkers of SVD, by evaluating metrics extracted from breath-hold BOLD-fMRI in terms of their predictive power of cognitive impairment in a group of SVD patients. We modelled the breath-hold BOLD-fMRI response using a sinusoidal approach, and derived both CVR amplitude and delay-based maps. Multiple linear regression analysis showed that CVR metrics significantly contributed to explain cognitive impairments in working memory, long-term memory and executive function. |
| 3722 | Computer 43
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Amplitude of low-frequency fluctuations in resting-state BOLD-fMRI is associated with cognitive decline in cerebral small vessel disease |
1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico – Universidade de Lisboa, Lisboa, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisboa, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal, 5Imaging Department, Hospital da Luz, Lisboa, Portugal |
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Cerebral small vessel disease (SVD) is a major vascular contributor to dementia and stroke, being associated with age-related cognitive decline. In this work, we aim to assess the potential of spontaneous BOLD fluctuations metrics to predict cognitive impairment in a group of SVD patients, therefore providing sensitive SVD biomarkers. The amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF) were computed in four different frequency bands as metrics of spontaneous BOLD signal fluctuations. Results from multiple linear regression analyses demonstrated that spontaneous BOLD fluctuations metrics contribute to the prediction of cognitive impairment in executive function, processing speed and working memory. |
| 3723 | Computer 44
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Voxel-wise analysis of functional MRI activation in regions of provoked impaired cerebrovascular reactivity: a translational model |
1University Hospital Zurich, Zurich, Switzerland, 2University of Toronto, Toronto, ON, Canada |
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A voxel-wise investigation of the relationship between the cerebrovascular reactivity (BOLD-CVR) alteration and the task-evoked Blood-oxygenation-level dependent functional MRI (BOLD-fMRI) challenges the commonly accepted linear and global correction method used. Our controlled CVR modulation in healthy subjects is a good investigation translational model for patients affected with glioblastomas or stroke. |
| 3724 | Computer 45
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Cerebral blood flow affected by the order of functional tasks |
1Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 2Center for MRI Research, Peking University, Beijing, China |
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This study investigates the order effect of functional task-induced CBF responses. ASL sequence was implemented to quantify CBF responses to the same task but in paradigms of different task orders in both the motor and visual cortices. Results of the study show an order effect in which that the greater the work load of the prior task, the greater influence it can exert on the CBF response of the posterior task. This study emphasizes the importance of the randomized task design and gives insight on underlying task-induced CBF response mechanisms. |
| 3725 | Computer 46
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VASO signal decreases associated with BOLD increases: a possible role of CSF volume redistribution |
1School of Physics & Astronomy, Cardiff University, Cardiff, United Kingdom, 2NIMH, Bethesda, MD, United States |
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Using manipulations of the arterial tension of carbon dioxide, we demonstrate that the paradoxical decrease in CBV associated with BOLD increases is restricted to voxels with large proportions of CSF. Excluding those voxels , we show that visual responses during hypercapnia have no change in amplitude in VASO and BOLD contrasts, but the time-to-peak of BOLD responses lengthens and CBV peak times, being longer at baseline, remain the same. |
| 3726 | Computer 47
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Fast fMRI responses supported by inter-voxel variability of hemodynamic response functions |
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge, MA, United States, 4Radiology, Stanford University, Palo Alto, CA, United States, 5Biomedical Engineering, Boston University, Boston, MA, United States |
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In this abstract, we use very high-resolution fMRI to evaluate inter-voxel variability of hemodynamic response functions (HRF) elicited by a visual task. We show that HRFs exhibit wide variability across voxels, with a subset of HRFs occurring at temporal scales much faster than the canonical HRF, which we consider as one mechanism that underlie fast neural-activity-related dynamics. Influence of spatial resolution on HRF dynamics are also evaluated, we show that the use of small voxels (without spatial averaging) sampling parenchymal signals may enable faster observed hemodynamics. |
| 3727 | Computer 48
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Title: A Closer Look at the Vascular Component of Hemodynamic Response Function and Its Variations by Aging |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute, Baycrest Centre, Toronto, ON, Canada |
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It has been shown that the brain vasculature changes with aging. The unhealthy brain vasculature is associated with risks of a lot of conditions such as stroke and ischemic attacks. Moreover, some studies have confirmed the causality of the impaired vasculature and the diseases of aging such as Alzheimer’s disease. Herein, we study the effect of aging on the vascular component of the hemodynamic response function. The results demonstrated narrower and more positively skewed distributions of peak spectral power in older controls which indicate degradation in some regions of the brains of the older adults. |
| 3728 | Computer 49
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The Effect of End-tidal PETCO2 Clamping on Resting-state fMRI Connectivity |
1Department of Psychology, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute at Baycrest, Toronto, ON, Canada, 3Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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The pressure of end-tidal CO2 (PETCO2) has a significant impact on the blood oxygenation level dependent (BOLD) signal and clamping it leads to detecting additional brain activation in task-based fMRI. However, the effect of PETCO2 clamping on the resting state connectivity has not been yet investigated. In this study we compared whole brain connectivity patterns of 13 healthy subjects during free-breathing and clamped PETCO2. Results showed clamping the PETCO2 removes the global and widespread effect of PETCO2 fluctuation in the gray matter, leading to weaker connectivity and more between-subject variability in the connectivity values. |
| 3729 | Computer 50
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Deriving cardiac waveforms from fMRI data using slice selective averaging and a deep learning filter. |
1Harvard Medical School, Boston, MA, United States, 2McLean Hospital Brain Imaging Center, Belmont, MA, United States |
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This work is a new technique to find Cardiac waveform from the fMRI data. For that purpose, a three stage data analysis is performed. In the first two stages, a candidate signal is derived by averaging over the voxels in every slice and combining them with proper time delays and resampling to 25Hz. As the third stage a deep learning architecture is used to improve the signal quality. The reconstructed signal is a good estimate of the plethysmogram data which is collected simultaneously with fMRI data. |
| 3730 | Computer 51
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Sensorineural hearing loss and cognitive impairments : contributions of thalamus using multimodal MR |
1Department of Radiology, Jiangsu Key laboratory of Molecular Imaging and Functional Imaging, Nanjing, China, 2Department of Radiology, Zhongda Hospital, Nanjing, China, 3Medical School of Southeast Univeristy, Nanjing, China |
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In present study, we systematically investigated the structure, function and perfusion features of the TH and its seven subdivisions through multimodal MRI, aiming to uncover the potential role of the TH in SNHL and its correlations with cognition measurements. |
| 3731 | Computer 52
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Altered Brain Structure and Function Correlate with Disease Severity and Affective Disorders in Patients with Hemifacial Spasm |
1Department of Medical Imaging, the first affiliated hospital of Xi'an Jiaotong University, Xi'an, China |
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Hemifacial spasm (HFS) is characterized by unilateral and paroxysmal contraction of orofacial muscles. A group of HFS patients and healthy controls underwent MRI examination and clinical assessment for facial spasm and affective disorders. HFS patients showed thickened left fusiform in cortex along with reduced subcortical volume in the right amygdala. Increased amygdala-driven connections were revealed to the bilateral superior frontal gyrus (SFG) and orbital gyrus (OG), and increased functional connectivity (FC) was detected of fusiform seed to several subregions of frontal lobe. These altered FC changes were associated with certain clinical indices, providing new insight into pathophysiology of the disease. |
| 3732 | Computer 53
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Distinct Patterns of Interhemispheric Connectivity in Patients with Early- and Late-Onset Alzheimer’s Disease |
1The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China, 2GE Healthcare Shanghai, Shanghai, China |
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Early-onset Alzheimer’s disease (EOAD) presents a different clinical profile than late-onset Alzheimer’s disease (LOAD). We used voxel-mirrored homotopic connectivity (VMHC) to examine interhemispheric functional connectivity and tract-based spatial statistics (TBSS) to reflect the diffusion index. We found EOAD patients exhibited more widely disrupted interhemispheric functional and structural connectivity, which related to executive deficits. Our study suggested that different interhemispheric connectivity damage patterns may contribute to the distinctclinical profiles in EOAD and LOAD. |
| 3734 | Computer 54
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IVIM-based cerebral perfusion (in ml/100g/min) values at rest, hypercapnia and ischemia in an MCA occlusion model |
1Department of Radiology, University of Chicago, Chicago, IL, United States, 2Bioengineering and Biomedical Engineering, Northwestern, Chicago, IL, United States |
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This is a preliminary study of intravoxel incoherent motion (IVIM) in a two day study of normocapnia, hypercapnia, and post middle cerebral artery occlusion. It was established that IVIM perfusion values are linearly correlated to the reference perfusion values under a variety of physiologic states meaning IVIM perfusion values can be easily quantified. Once scaled, the IVIM CBF of white matter and grey matter normocapnia and post-occlusion cortex on both hemispheres were strongly correlated to the reference standard. |
| 3735
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Computer 55
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Mapping Brain Neurochemical and Functional Coupling Using Dynamic SPICE |
1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China |
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Neuronal metabolite (e.g., glutamate, GABA) concentrations in the brain are known to be correlated with neural activity. Currently, fMRS is the primary tool for measuring neurochemical changes in response to brain activity. However, fMRS has several major practical limitations, including low spatial resolution, low SNR, and very limited brain coverage. In this work, a new dynamic 1H-MRSI technique is used to address these difficulties. This technique can map dynamic metabolic changes from the whole brain at high spatial and temporal resolutions. In addition, it can simultaneously acquire fMRI images to track brain functional activity during the scan. With this unique capability, we have carried out functional MRSI experiments with motor tasks to investigate the coupling between neural metabolism and neural activity. The experimental results clearly show an increase in Glx in the motor cortex during the motor activation. |
| 3736 | Computer 56
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Quantitative functional imaging of visual cortex activity in humans using multi-parametric blood oxygenation level dependent MRI |
1Neuroradiology, Technische Universität München, Munich, Germany, 2TUM-NIC, Technische Universität München, Munich, Germany, 3Clinic for Neurology, Technische Universität München, Munich, Germany, 4MRRC, Yale University, New Haven, CT, United States |
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Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used to assess local neuronal activity. However, the absolute metabolic demand related to BOLD-signal change is still largely unknown. In the current study we investigated the feasibility of multi-parametric quantitative BOLD (mq-BOLD) measurements to detect changes in tissue oxygenation in healthy, cortical gray matter during different states of visual stimulation. Our results show that mq-BOLD measurements are well feasible for standard activation paradigms. However, subject motion and transient states of brain activation might impact on quantitative parameter mapping due to longer acquisition times. |
| 3737 | Computer 57
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Dysfunction of functional connectivity between default mode network and cerebellar structures in patients with mTBI in acute stage. rsfMRI and DTI study. |
1Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russian Federation, 2Institute of Biochemical Physics Russian Academy of Sciences, Moscow, Russian Federation, 3Semenov institute of Chemical Physics of Russian Academy of Sciences, Moscow, Russian Federation, 4Philips Healthcare Russian Federation, Moscow, Russian Federation |
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The revealed changes in DMN neuronal connection and cerebellar regions in acute stage of mTBI patients can be an initial step of damages leading to cognitive deficit which can be developed in future in long-term period of injury. We suggest that further research in this direction will demonstrate whether DMN functional integrity analysis can serve as a biomarker for monitoring the recovery of patients with mTBI. |
| 3738 | Computer 58
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Towards a more precise and comprehensive characterization of the relationship between EEG alpha rhythm and thalamic BOLD signal |
1Rotman Research Institute at Baycrest, North York, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Department of Radiology, University Medical Center Freiburg, Freiburg, Germany |
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In this study, the relationship between EEG alpha band power and the BOLD signal is examined in the thalamus. We overcome previous limitations in temporal resolution by using fast fMRI (MREG) acquisitions. We also consider a wider range of lags between EEG and BOLD signals than previous studies. In addition, cross correlations between alpha EEG and fMRI signals from all voxels in the thalamus region of all subjects are automatically classified using clustering to reveal consistent spatial-temporal patterns in the relationships between EEG alpha activity and BOLD signals in different parts of thalamus. |
| 3739 | Computer 59
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Connectivity in the Default Mode Network of Schizophrenic Patients Investigated with Microstates and mGluR5 Receptor Availability Using Simultaneously Recorded Trimodal ([11C]ABP688-PET/MR/EEG) Imaging |
1Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany, 2Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany, 3JARA - BRAIN - Translational Medicine, Jülich, Aachen, Germany, 4Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada, 5Institute of Neuroscience and Medicine 2, INM-2, Forschungszentrum Jülich, Jülich, Germany, 6Institute of Neuroscience and Medicine 5, INM-5, Forschungszentrum Jülich, Jülich, Germany, 7Department of Nuclear Medicine, RWTH Aachen University, Aachen, Germany, 8Institute of Neuroscience and Medicine 11, INM-11, Forschungszentrum Jülich, Jülich, Germany, 9Department of Neurology, RWTH Aachen University, Aachen, Germany |
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This exploratory study aims at underpinning the relationship between functional connectivity (fMRI), microstates (EEG) and glutamatergic receptor (mGluR5) availability ([11C]ABP688-PET) in healthy controls (HC) and schizophrenic (SZ) patients using simultaneously acquired trimodal (PET/MR/EEG) data. The single modality results show hyperactivity in vDMN regions of SZ patients (fMRI), a significant decrease in volume of distribution (Vt) of SZ patients (non-smoker group), and increased microstate global field power (GFP) in SZ patients. Correlations between Vt and GFP did not reveal any significant results, but the trend suggests a strong influence of smoking status and its association with global reductions in mGluR5 availability. |
| 3740 | Computer 60
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Detection of oscillatory event-related visual potentials and BOLD signals using interleaved simultaneous multi-slice inverse imaging and electroencephalography |
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2Department of medical imaging, Taipei Medical University – Shuang Ho Hospital, New Taipei City, Taiwan, 3Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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We propose to interleave simultaneous multi-slice inverse imaging (SMS-InI) concurrently with EEG. In this way, EEG recorded with gradient-artifact-free intervals (1.9 |
| 3741 | Computer 61
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Correspondence between structure and function in the human brain using data from over 15,000 individuals |
1Brainnetome Center and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China, 2University of Chinese Academy of Sciences, Beijing, China, 3The Mind Research Network, Albuquerque, NM, United States, 4Department of Psychology, Neuroscience Institute, Georgia State University, Atlanta, GA, United States, 5Department of Electrical and Computer Engineering, the University of New Mexico, Albuquerque, NM, United States, 6Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States |
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This study compared the structural-functional correspondence on a large discovery dataset (7104 functional scans, 6005 structural scans) and a replication dataset (9214 subjects). Independent component analysis was applied to identify structural and functional networks. Spatial correlation was then computed using Pearson correlation and mutual information. Results indicated that 1) 24 replicated pairs were identified showing high structural-functional correspondence; 2) the structural-functional correspondence showed the following hierarchy: Basal ganglia > Somatomotor, Visual > DMN, Temporal, Cerebellum > Frontal and Parietal domains; 3) replicated results allowing us to provide evidence of a stable template of structural-functional correspondence for the public to use. |
| 3742 | Computer 62
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On the variability of cardiac pulse artifacts across heartbeats affecting EEG recordings in simultaneous EEG-fMRI: a 7T study |
1Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Functional Brain Mapping Lab, University of Geneva, Geneva, Switzerland, 3Biomedical Imaging Research Center (CIBM), Lausanne and Geneva, Switzerland, 4Department of Radiology, University of Lausanne, Lausanne, Switzerland, 5Department of Radiology, University of Geneva, Geneva, Switzerland |
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EEG recordings performed in MRI scanners suffer from complex artifacts caused by heart function, termed pulse artifacts (PAs), which can strongly compromise EEG quality. This study investigated the properties and mechanisms of PA variability across heartbeats, which remains poorly understood. Simultaneous EEG-fMRI was performed at 7T on healthy participants with concurrent breathing and cardiac recordings. PA variability showed an important impact on EEG quality, and was linked not only to changes in head position/orientation across time, but also, and more importantly, to respiration and heart rate. These findings have important consequences for PA correction, highly relevant to most EEG-fMRI applications. |
| 3743 | Computer 63
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The Relationship between Local Field Potential and Blood-oxygenation-level Dependent Signal Can Be Nonlinear |
1Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States |
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Many studies that involve simultaneous local field potential (LFP) and blood-oxygenation-level dependent (BOLD) signal measurements use correlation analysis, which assumes a linear relationship between the two. To experimentally determine whether the relationship is linear, we obtained a LFP vs BOLD response curve from simultaneous LFP and BOLD measurements. The relationship between the two was nonlinear under isoflurane but not under dexmedetomidine, which suggests that correlation may not always correctly capture the relationship between LFPs and BOLD. |
| 3744 | Computer 64
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Divergent structural and functional changes across brain hierarchy account for population variation in demographics and behavior |
1Biomedical Engineering, Pennsylvania State University, State College, PA, United States, 2Institute for Cyber Science, Pennsylvania State University, State College, PA, United States |
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A robust link was recently established between resting-state functional connectivity and human behavioral measures. To understand the structural basis underlying this relationship, we examined the population covariation of the cortical thickness, resting-state connectivity, and a set of demographic and behavioral measures. We found that divergent changes at the lower- and higher-order brain regions in the cortical thickness and resting-state connectivity are structural and functional imaging features that are most tightly linked to the population behavioral variation. The findings suggest that differentiated changes across brain hierarchy could be important to brain function. |
| 3745 | Computer 65
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Rhythmic EEG inputs modulate the thalamocortical network in epilepsy |
1University of Electronic Science and Technology of China, Chengdu, China |
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Thalamus has the capacity to generate oscillations characterized by different frequency and levels of synchrony. However, little is known of what function the generated EEG dynamic pattern may serve in thalamocortical interactions. In this study, we used psychophysiological interaction framework to detect fMRI thalamocortical coupling modulated by dynamic EEG connectivity patterns, and tested the alteration of the modulatory couplings in juvenile myoclonic epilepsy. The results found frequency-dependent characteristics for the thalamocortical coupling. The group comparison revealed the couplings were altered with certain thalamus sets involved in JME, which may have implications for better understanding of the thalamocortical circuit influenced by epileptic activity. |
| 3746 | Computer 66
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Classification of BOLD-fMRI dynamic functional connectivity states based on simultaneous EEG microstates |
1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Ténico, Universidade de Lisboa, Lisboa, Portugal, 2Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT) and CNC.IBILI, University of Coimbra, Coimbra, Portugal, 3Department of Neurophysiology, Centro Hospitalar Psiquiátrico de Lisboa, Lisboa, Portugal |
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Dynamic functional connectivity (dFC) states have been identified in BOLD-fMRI data, but their electrophysiological underpinnings remain a matter of debate. The simultaneous acquisition of the EEG has previously allowed the identification of EEG signatures of dFC states. Here, we further investigated whether EEG microstates can be used to classify dFC states. We found that highly accurate classification could be achieved based on the three EEG microstates with the highest global explained variance, in simultaneous EEG-fMRI data acquired from eight epileptic patients. These results further support the electrophysiological underpinnings of fMRI dFC states, highlighting their relationship with EEG-derived microstates. |
| 3747 | Computer 67
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Adipose Tissue Evaluation in Economic Fish with MRI Imaging Translation via Conditional Generative Adversarial Networks |
1Ocean University of China, qingdao, China, 2Radiology Department,Bosto Children's Hospital; and Harvard Medical School, Boston, MA, United States |
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High presence of excess fat makes strong implications in obesity and its complications. High-fat diet could trigger fat accumulation. In this paper, we investigated and developed one quantitative online assessment strategy for adipose tissues in economic fish with Conditional Generative Adversarial Networks (CGAN) by means of magnetic resonance imaging (MRI), which could automatically help insights into the morphology of the adipose tissues in fish. |
| 3748 | Computer 68
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BOLD Representation of Canonical EEG Microstates |
1Laureate Institute for Brain Research, Tulsa, OK, United States, 2Electrical and Computer Engineering, University of Oklahoma, Norman, OK, United States, 3Japan Society for the Promotion of Science, Tokyo, Japan, 4Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States |
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We extracted the topographical similarity of EEG signals with four canonical EEG microstate (EEG-ms, A through D) templates from 47 healthy subjects. Then, a general linear model (GLM) examined topographical similarities using time courses convolved with hemodynamic response function (HRF) as regressors of interest for individual subjects. A one-sample t-test was applied |
| 3749 | Computer 69
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Evaluation of a flexible polyimide-based microelectrode array for MR-compatibility and recording performance in 7T research system |
1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, 2Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China, 3Department of Biomedical Engineering, National Yang Ming University, Taiwan, China, 4College of Biomedical Engineering & Instrument Science，Zhejiang University, Hangzhou, China, 5The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China |
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For simultaneous recording of spike signal and functional magnetic resonance imaging (fMRI) response, both MR-compatibility and performance of electrophysiological signal acquisition of the electrode matters. Previously, we have designed a flexible polyimide-based microelectrode array which has good biocompatibility, as well as high and stable signal-to-noise ratio for chronic recording. This study evaluated the MR-compatibility and recording performance of microelectrode array in the 7T research system (Siemens, Erlangen, Germany). The results suggest that it has the potential to facilitate simultaneous spike-recording during MR scanning in 7T. |
| 3750 | Computer 70
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Line Scanning fMRI combined with optical calcium recordings to resolve the direct BOLD response to underlying slow oscillation-associated traveling waves |
1AG Molecular Imaging and Optogenetics of the Institute of Pathophysiology, University Medical School of Johannes Gutenberg-University Mainz, Mainz, Germany |
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In this multimodal approach consisting of line scanning (ls)-fMRI combined with optical calcium recordings, we investigated the direct BOLD response on a sensory stimulus in the slow wave brain state in anesthetized rats. We were able to observe the fMRI correlate of a slow wave recruiting the field of view with a significant latency between the recruitment of posterior and anterior voxels. This latency suggest the identification of the propagation of slow waves, as described with optical methods. |
| 3751
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Computer 71
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Optogenetic fMRI of large-scale vestibular system and their cross-modal functions |
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, 3Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China, 4School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China |
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The vestibular system - pivotal for our sense of balance and orientation - integrates input from our other dominant senses, such as audition and vision, to create a multisensory percept. However, little is known regarding the extent of modulatory effects (if any) that the vestibular system exerts on the other sensory processing. Here, our report combined fMRI, optogenetics and sensory stimuli to provide large-scale brain-wide insights into the extent of cross-modal modulatory effects of the vestibular system on sensory processing. We reveal that vestibular nucleus optogenetic stimulation can modulate auditory and visual sensory processing at midbrain, thalamic and cortical regions. |
| 3752
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Computer 72
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Optogenetically-evoked spindle-like activity from thalamus propagates brain-wide and enhances rsfMRI connectivity |
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China |
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Hierarchical nesting of spindles and slow oscillations have been identified as a unique characteristic for long-range functional neural integrations in |
| 3753 | Computer 73
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Towards artefact-free awake rat brain fMRI/EEG studies with multiband-SWIFT fMRI |
1A.I.V. Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States |
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EPI sequence is the most common choice for fMRI investigations. EPI, however, is loud for awake studies, prone to susceptibility-induced artefacts, and sensitive to motion. Therefore, we investigated whether the unique features of MB-SWIFT would make it a potential alternative for EPI to overcome these issues. Our results suggest that MB-SWIFT is dramatically more silent compared to EPI, body movement does not affect the voxels in brain, gradient-switching artefacts are minimal in electrophysiological data, and good quality resting-state fMRI data can be obtained from awake rats. We conclude that MB-SWIFT is an advantageous alternative to EPI in demanding experimental applications. |
| 3754 | Computer 74
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Long-term effect of isoflurane anesthesia on functional connectivity detected by fMRI and local field potential measurements |
1A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland |
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Isoflurane, a commonly used anesthetic in preclinical studies, is known to alter functional connectivity during anesthesia. It has been found that isoflurane can induce brain plasticity and cause long-term changes on brain function. Therefore, we studied the connectivity changes caused by single isoflurane (3h, 1.8%) exposure after a one-month waiting period by resting state fMRI and local field potential (LFP) measurements. Treated rats exhibited significantly strengthened connectivity between hippocampus and somatosensory cortex both in fMRI and LFP, indicating long-term modulation of brain activity by single administration of isoflurane anesthesia compared to non-treated controls. |
| 3755 | Computer 76
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Blocking AQP4 channels impacts BOLD fMRI but not Diffusion fMRI response patterns induced by visual stimulation |
1NeuroSpin, CEA, Saclay, France |
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We compared BOLD and Diffusion fMRI mouse brain maps obtained through visual stimulation before and after TGN-020 administration, an AQP4 receptor antagonist and astrocyte swelling inhibitor. Activations were observed in the primary visual cortex and the superior colliculus with both methods. BOLD signal changes were significantly increased after AQP4 inhibition, while the DfMRI signals were not affected. These results suggest that the DfMRI signal does not originate from astrocyte swelling. |
| 3756 | Computer 77
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Hemodynamic response of white matter to event-related functional tasks |
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States |
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There is increasing evidence that white matter (WM) elicits robust blood oxygenation level-dependent (BOLD) responses to |
| 3757 | Computer 78
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Improved Selection of Hemodynamic Response Function in ASL Based Perfusion fMRI |
1Laureate Institute for Brain Research, Tulsa, OK, United States, 2Cornell MRI Facility, Cornell University, Ithaca, NY, United States, 3Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States |
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Two types of hemodynamic response function (HRF) are used in the data analysis of ASL based perfusion fMRI (ASL-fMRI): single gamma function (1-gamma) and the sum of two gamma functions (2-gamma). This study aims to optimize the selection of HRF by comparing the performances of standard 1-gamma and 2-gamma HRFs and also a modified 2-gamma HRF, which has earlier response peak time than the standard one. Our visual ASL-fMRI experiment indicate that the modified 2-gamma provides the best detection sensitivity and we recommend to use it in ASL-fMRI. |
| 3758 | Computer 79
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The role of perivascular spaces in white matter blood oxygenation level dependent MRI |
1UBC MRI Research Centre, Vancouver, BC, Canada, 2Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 3Pediatrics, University of British Columbia, Vancouver, BC, Canada, 4Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 5Division of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada |
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Using vascular parameters obtained from dynamic susceptibility contrast MRI, the gradient echo and spin echo blood oxygenation level dependent (BOLD) signals were simulated at 3 and 7T in order to investigate the effects of tissue orientation and perivascular spaces. We show that both the magnitude and the tissue orientation dependence of the BOLD effect is amplified by perivascular spaces. |
| 3759 | Computer 80
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Electrical Properties Tomography based Functional Magnetic Resonance Imaging (EPT-fMRI) |
1Philips Research, Hamburg, Germany |
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This study presents a new approach for the assessment of functional brain areas by using Electrical Properties Tomography (EPT). The measurements are performed similarly to conventional fMRI experiments to investigate brain activation for primary motor cortex areas, whereas EPT maps are generated for activation and resting periods and compared to BOLD fMRI images. |
| 3760 | Computer 81
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Cortical depth- and feature-dependent intrinsic functional connectivity in human visual and auditory cortices |
1National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3Department of Radiology, Harvard Medical School - Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 4Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 5Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland |
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This study reveals the tonotopy- and retinotopy-dependent intrinsic functional connectivity (iFC) across cortical depths in the human auditory and visual cortieces, respectively. Using 7T fMRI data with 1-mm isotripic resolution, we demonstrated that feature-dependent iFC have a higher selectivity in the primary sensory than in the secondary sensory area. The selectivity was generally higher as we moved from superficial to deep cortical depths, while the difference between the primary sensory and secondary sensory area was more prominent in the intermediate cortical depth. |
| 3761 | Computer 82
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Correlation between inter-cortical depth hemodynamic responses and oscillatory neuronal responses during music listening |
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3Neurology Department, Taipei Veterans General Hospital, Taipei, Taiwan, 4Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 6Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland |
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We explored the correlation between cortical depth-specific BOLD signal and oscillatory neuornal activity during music listening using high resolution fMRI data (3T with 1.5 mm isotropic resolution) and stereotactic electroencephalography. Three findings are: first, the hemodynamic responses in human auditory cortex was significantly correlated with neuronal oscillation in high gamma band (40 Hz to 90 Hz). Second, the intermediate cortical depth was more closely related to neuronal oscillation. Third, the neuronal-hemodynamic correlation was higher in core than in noncore region. |
| 3762 | Computer 83
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BOLD-fMRI Using a 3D Ultrafast Gradient-echo-based Sequence Using Quadratic-phase Encoding (RASE-II) in Comparison with 2D and 3D EPI |
1Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of, 2Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of |
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We recently introduced a novel ultrafast 3D gradient-echo-based imaging technique using spatio-temporal encoding (SPEN) or quadratic-phase encoding, which were dubbed RASE-I and -II (Rapid Acquisition with Sequential Excitation). RASE has less sensitivity to field inhomogeneities and susceptibility differences compared to conventional gradient-echo EPI (GE-EPI), sharing the advantages of 3D imaging such as high signal-to-noise ratio and high spatial resolution. In this study, we present promising results of RASE-II fMRI, i.e., better t-scores, tSNR than conventional 2D and 3D GE-EPI, on a 9.4-T animal scanner. |
| 3763 | Computer 84
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Laminar fMRI with T2-prepared multi-echo FLASH |
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany, 2High Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, Germany |
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Examining signal changes at the level of cortical layers using T2*-weighted fMRI suffers from a systematic bias caused by extravascular effects of draining veins. T2-weighting promises higher specificity to signal changes near the origin of neural activity. In this work, we use a T2-prepared, multi-echo FLASH sequence at 7 T in a flickering checkerboard experiment targeting the visual cortex to investigate the feasibility of this sequence for laminar fMRI. The layer profiles indicate the desired T2-weighted response in grey matter, but also a peak at the pial surface likely caused by intravascular effects in the pial veins. |
| 3764 | Computer 85
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fMRI signal oscillations in rats can be induced by electric paw stimulation but do not deteriorate the observed BOLD peak |
1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany |
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Signal time courses of BOLD fMRI measurements in rodents often show a damped oscillation which may superimpose with the expected hemodynamic response. In order to explore and characterize these oscillations, we performed EPI-BOLD measurements with high temporal resolution upon electrical paw stimulation. 55 % of the measurements showed oscillations with a frequency of 0.2 Hz. We could verify that these oscillations were induced by stimulation but did not affect the BOLD response. Consequently, hemodynamic response function models for statistical analysis are valid independently from the occurrence of oscillations. |
| 3765 | Computer 86
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Longitudinal study of BOLD HRF in human cortex |
1Neuroscience, Baylor College of Medicine, Houston, TX, United States, 2Baylor College of Medicine, Houston, TX, United States |
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A simple audiovisual stimulus combined with a fast-paced task evoked a strong HRF across a majority of cerebral cortex during four scanning sessions to measure the repeatability of BOLD over time. HRFs were characterized by spatial and temporal parameters and showed remarkable correlation across the time points, which spanned three hours, three days, and three months. Results showed that HRFs are repeatable for consistent quantification of neurovascular coupling. |
| 3766 | Computer 87
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R1 and R2 characterization of human blood with phase-cycled balanced steady-state free precession (bSSFP) |
1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Graduate Training Centre of Neuroscience, IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany, 3Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany |
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Balanced steady-state free precession (bSSFP) sequences have received increased interest for functional BOLD experiments since, in contrast to conventional EPI-based techniques, they are not prone to geometric distortions in the phase encoding direction. Characterization of measured BOLD signal changes requires consideration of extravascular as well as intravascular contributions. Knowledge about the relaxation rates of human blood is a prerequisite to quantify the intravascular contribution to the BOLD effect. Here, R1 and R2 relaxation rates of blood samples are intrinsically obtained from a series of phase-cycled bSSFP scans to account for the repetition time dependence of R2 due to rapid refocusing. |
| 3767 | Computer 88
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Revisiting mental chronometry with isotropic resolution and full brain coverage. |
1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany |
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In this project, we are using a multiband echo-shifted EPI sequence for TR less than 160 ms combined with a novel analysis approach to measure interregional BOLD onset times from a visual-motor association task with full brain coverage and isotropic resolution. |
| 3768 | Computer 89
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Voxel-Specific Modeling of Physiological Fluctuations in BOLD fMRI Signal |
1University of California, Irvine, CA, United States |
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Cardiac pulsation and respiration have significant contributions to the BOLD signal. This is particularly challenging given the long TRs typically used in BOLD experiments since these fluctuations are at higher frequency than the sampling rate and therefore aliased to lower frequency components. This study presents a new voxel-specific method accounting for the physiological effects in BOLD time series signal. We show that this approach is able to improve the estimation of physiological effects compared to the widely used RETROICOR method. |
| 3769 | Computer 90
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Effects of Spinal Cord vascular geometry on the BOLD-fMRI contrast |
1IRCCS Fondazione Santa Lucia, Rome, Italy, 2Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy, 3A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 4CNR-Nanontec, c/o Dipartimento di Fisica, Rome, Italy |
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The effects of the spinal cord (SC) vessel topology on the blood oxygenation level dependent (BOLD) signal is poorly characterized. We performed numerical simulations on models of vasculature |
| 3770 | Computer 91
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MP-PCA denoising to improve detection of task-based fMRI activation in brain tumor patients |
1Radiology, Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States |
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Functional MRI improves preoperative planning in brain tumor patients, however BOLD signal changes for task-based 3T fMRI are only 2-4% and the tumor often compromises patient performance. This retrospective study evaluated Marchenko-Pastur Principle Component Analysis (MP-PCA) denoising to increase sensitivity for cortical regions recruited during language task-based fMRI paradigms in brain tumor patients. MP-PCA denoising is shown to improve the clinical value and practical utility of performing preoperative fMRI in brain tumor patients. |
| 3771 | Computer 92
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Dynamic Model-based Reconstruction for Oscillating Steady State fMRI |
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States |
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We introduce Oscillating Steady State (OSS) fMRI, a method that uses quadratic phase cycling and balanced gradients to create an oscillating T2* sensitive signal. We also present a model-based reconstruction that converts these signal oscillations into B0 estimates, enabling correction for respiratory or scanner induced signal changes. OSS fMRI enables the SNR benefits of bSSFP-based methods, while adding T2* sensitivity and B0 encoding into a unique oscillating signal. |
| 3772 | Computer 93
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Monte Carlo simulation of VASO fMRI from real microvascular angiograms of the mouse cortex |
1Université Laval, Quebec, QC, Canada, 2Massachussets General Hospital, Boston, MA, United States, 3University of California, San Diego, San Diego, CA, United States, 4Boston University, Boston, MA, United States |
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The vascular space occupancy (VASO) fMRI method probes changes in cerebral blood volume (CBV) but subsequent BOLD response contaminates the VASO signal reducing its SNR. Quantifying this BOLD contamination for different pulse-sequence parameters would improve our ability to measure CBV changes and optimize their quantification in a variety of physiological states and diseases. We have implemented a Monte Carlo method to model such effect from experimental cortical angiograms measured with two-photon microscopy on mice brains. Our results indicate that at 3T the BOLD contamination is relatively low (below 10%) but that this contamination is much higher at 7T and above. |
| 3773 | Computer 94
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Comparing correlation between BOLD and susceptibility changes during Resting state and Task-based experiments |
1Centre for Functional and Metabolic Mapping, Western University, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada |
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Quantitative susceptibility mapping (QSM) is a technique widely used for the measurement of venous oxygen saturation levels, through local deoxyhemoglobin concentration. In this work, QSM is used to explore the relationship between magnetic susceptibility and BOLD signal changes during resting state and task based fMRI experiments, in order to better understand their cerebrovascular mechanisms. Negative correlations between susceptibility and BOLD signal were observed and evaluated for both resting state and task based experiments. |
| 3774 | Computer 95
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Influence of multiband factor on temporal SNR limits using a clinical BOLD-EPI sequence |
1Department of Radiology, Ghent University Hospital, Gent, Belgium, 2Department of Diagnostic Sciences, Ghent University, Ghent, Belgium, 3Department of Data Analysis, Ghent University, Ghent, Belgium, 4Department of Experimental Psychology, Ghent University, Ghent, Belgium |
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Detectability of BOLD signal change is determined by temporal SNR (tSNR, mean divided by standard deviation of the signal over time), and ultimately determines how long needs to be scanned to obtain significant results in a fMRI experiment. With the clinical availability of multiband BOLD-EPI, TR can be shortened significantly, but it is unclear how MB factor influences tSNR. We show in a human subject that tSNR limits up to 192 can be reached and that multiple combinations of MB factor and voxel size can be used to reach similar tSNR values. |
| 3775 | Computer 96
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On the detection of resting-state correlations at high-frequencies under hyper- and hypo- capnic conditions |
1Neurology, University of New Mexico, Albuqueruque, NM, United States, 2University of New Mexico, Albuqueruque, NM, United States, 3Mind Research Network, Albuqueruque, NM, United States |
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In this study, we investigate the detection of resting-state fluctuations at higher frequencies using changes in global blood flow using hyper- and hypo- capnic conditions. A new adaptive TR approach enables higher sensitivity for detecting the resting-state fluctuations at higher frequencies through optimized TR that is tailored to the individual cardiac and respiratory rates. We were able to detect major resting-state networks (sensory motor, default-mode, and auditory) at frequencies between 0.45-0.8 Hz in normo-, hyper-, and hypo- capnic conditions. |
| 3776 | Computer 97
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The latency differentiates BOLD responses elicited by congruent and incongruent McGurk audio-visual stimulus pairs |
1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 2National Taiwan University, Taipei, Taiwan, 3National Yang-Ming University, Taipei, Taiwan, 4Department of Mediacl Biophysics, University of Toronto, Toronto, ON, Canada, 5Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland |
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We used fast fMRI sampled at the 10-Hz rate to study fMRI timing in audiovisual integration. Using the McGurk protocol, we found that the superior temporal gyrus (STG) had significant BOLD time-to-half (TTH) difference between the McGurk and congruent audiovisual stimuli pairs. The significance of TTH difference between congruent and McGurk was progressively more significant from posterior to anterior regions (p-values at visual cortex, lateral occipital lob, occipital parietal junction, STG, and auditory cortex were 0.13, 0.12, 0.05, 0.02, and 0.01, respectively), suggesting that incongruent audio-visual stimuli cause more delayed the brain response at regions closer to primary auditory processing. |
| 3777 | Computer 98
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Electrical conductivity as a potential mean to decouple the hemodynamic response from fMRI |
1Neurobiology, Weizmann Institute of Science, Rehovot, Israel |
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MR electrical properties imaging offers new means for probing physiological information in-vivo. The interest for fMRI lies in the dependence of electrical conductivity on structural macroscopic changes and on ionic concentration changes. In-vivo electrical conductivity acquisition has the potential to provide the means to decouple the hemodynamic response from fMRI. Changes in electrical conductivity can be measured using phase changes in a spin-echo experiment. We compared BOLD fMRI with phase changes in SE-EPI using basic visual task paradigm at 3T MRI, which showed faster time response and more localized spatial activation. Further study is required to analyze possible contributing factors. |
| 3778 | Computer 99
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The lag structure by BOLD-based blood flow tracking indicates the partial non-neuronal source of resting state functional connectivity in mouse |
1NeuroSpin/CEA-Saclay, Gif-sur-Yvette, France, 2Department of Psychiatry, Kyoto University Graduate School of Medicine, Kyoto, Japan |
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A BOLD-based tracking technique was applied to 11 mice to investigate the cerebral circulation. Mapping of the phase of low-frequency component, which is called as “BOLD-based lag structure” showed the typical vascular structure as previous study. Interestingly, BOLD-based lag structure in bilateral somatosensory cortex was similar with the resting state functional connectivity between the bilateral somatosensory cortex. These results indicate the feasibility of this technique in mouse model. Furthermore, our results implies the partial contamination of circulating blood flow in resting state functional connectivity in mouse model. |
| 3779 | Computer 100
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Drug cue-Induced brain response in protracted abstinence and methadone maintenance measures for heroin addiction: An event-related fMRI study |
1radiology department, Tangdu Hospital, the Fourth Military Medical University, Xi'an, China |
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Our research aims to compare PA with MMT,to reveal which abstinence way is better to recover the brain function in heroin-dependent individuals.24 heroin-dependent patients under PA ,19 heroin-dependent patients under MMT and 20 healthy volunteers were recruited. The functional images were acquired by using a spin-echo EPI. In the last part of this study, we proved PA is closer to healthy group.This study showed that PA is more advantageous than MMT to reduce heroin addiction in drug cue-reactivity. |
| 3780 | Computer 101
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fMRI of Radiologists with a Diagnosis Task |
1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Radiology, Stony Brook University, Stony Brook, NY, United States |
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Radiologists display superior perception in the analysis of medical images, but there are currently no fMRI studies of radiologists during a complex diagnosis task. In this study, radiologists read a variety of medical images and chose a diagnosis during fMRI. Compared to age- and education-matched controls, radiologists had lower functional activation in several visuospatial areas, including the lateral ocipital cortex and lingual gyrus. |
| 3781 | Computer 102
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fMRI Mapping of Cognitive Brain Networks Involved in Perceptual Bias |
1Brain Networks & Neurophysiology Lab, Halifax, NS, Canada, 2Department of Research, Nova Scotia Health Authority, Halifax, NS, Canada, 3Biomedical Translational Imaging Centre, Halifax, NS, Canada, 4Department of Anesthesia, pain management, and perioperative medicine, Dalhousie University, Halifax, NS, Canada, 5Pain Management Unit, QEII Health Sciences Centre, Halifax, NS, Canada, 6School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada, 7Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada, 8Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada, 9Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada |
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Prior expectations are critical in the formation of perceptions around phenomona such as pain. This study uses functional MRI to elucidate regions associated with both top-down and bottom-up aspects of pain perception, finding a network of higher-cortical regions for the former and primarily sensory regions for the latter. Additionally, bias towards cues rather than actual pain stimuli was both hypothesized and observed. The findings therefore shed light on the physiological basis of neural activation behind the complex and highly-biased formation of pain perceptions. |
| 3782 | Computer 103
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Cerebral blood flow changes associated with meditation practice time: a longitudinal study |
1State University of New York at Binghamton, Binghamton, NY, United States, 2Cornell University, Ithaca, NY, United States |
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Longitudinal cerebral blood flow (CBF) images were acquired in ten college students after 2-month meditation practice. The CBF difference before and after meditation practice and the association between CBF change and meditation practice time were analyzed on a voxel-by-voxel basis using SPM8. We found significant perfusion increase and decrease in the occipital and thalamus regions respectively. However, the CBF increase and decrease in the corresponding regions exhibited negative and positive association with practice time respectively. Regional analysis confirmed that the direction of CBF change may switch after some amount of meditation practice time, indicating a complex neural pathway of meditation. |
| 3783 | Computer 104
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Engagement of multiple networks during meditation: an fMRI study |
1Indraprastha Institute of Information Technology, New Delhi, India, 2Indian Institute of Technology, New Delhi, India, 3Centre for Advanced Research in Imaging, Neuroscience and Genomics, Mahajan Imaging, New Delhi, India, 4All India Institute of Medical Sciences, New Delhi, India |
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Long-term effects of meditation and the differences between meditators and non-meditators have been studied extensively. In order to understand the corresponding mechanisms of action, brain areas activated while meditating need to be studied. Such studies are limited due to lack of a suitable experimental paradigm and analysis technique. We investigated experienced meditators who underwent a 20 minutes audio-guided meditation in the fMRI scanner. Using the Intersubject correlation (ISC) analysis, correlated activity across the subjects was found in frontal pole, middle frontal gyrus, precuneus, primary somatosensory cortex, visual cortex, lingual gyrus, and cerebellum. |
| 3784 | Computer 105
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Effects of eleven-week aerobic exercises on working memory of deaf children estimated using task state functional magnetic resonance imaging |
1radiology department, AFFILIATED HOSPITAL OF YANGZHOU UNIVERSITY, YANGZHOU, China, 2MR Research China, Beijing, GE Healthcare, Beijing, China |
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In this study, we used a combined aerobic exercise and task functional magnetic resonance imaging (fMRI) on deaf children for eleven weeks to investigate the alternation of working memory function after exercise. The classic 2-back task included make odd-even judgment and short-term memory. The experimental group showed a significant improvement in the 2-back task performance and alternation of functional activity in temporal lobe, precuneus temporal lobe and precuneus. These findings may help to explain the synaptic plasticity of brain. |
| 3785 | Computer 106
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Dual-route mechanism for pictorial visual perception in developmental dyslexia |
1Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India, 3Department of Neurology, Fortis Hospital, New Delhi, India, 4Department of Psychiatry (Psychology Unit), All India Institute of Medical Sciences, New Delhi, India, 5Department of Linguistics, School of Language, Jawahar Lal Nehru University, New Delhi, India, 6Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India |
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Reading a window to world’s information, is a coordinated skill of grapheme-phoneme interface (letter-sound) at symbolic level. Inefficient mapping of this alphabets-horizontal string is labeled as dyslexia (reading problem). It can be developmental or acquired (post-stroke) disorder. Developmental dyslexia (DD) is heterogeneous state with disputed underlying mechanism(s) constraining optimal remediation. Compared to typical readers, DD literature is bifurcated into children with strength and impairment for visual perception. To unfold it neurobiologically, nonsymbolic visual processing role was studied. Observed bilateral brain activation (functional MRI) of ventral stream (inferior occipital and fusiform) and modified dorsal route-gating for figure-ground filtering in DD. |
| 3786 | Computer 107
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Subcortical and cortical fMRI assessment of auditory pathway function associated with lifetime noise exposure in normally hearing listeners |
1Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 2NIHR Nottingham Biomedical Research Centre, Nottingham, United Kingdom, 3Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, United Kingdom, 4Manchester Centre for Audiology and Deafness (ManCAD), University of Manchester, Manchester, United Kingdom, 5NIHR Manchester Biomedical Research Centre, Manchester, United Kingdom, 6Department of Psychology, Lancaster University, Lancaster, United Kingdom, 7University of Nottingham Malaysia, Jalan Broga, Selangor Darul Ehsan, Malaysia |
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We investigated the relationship of lifetime noise exposure with subcortical and cortical auditory fMRI BOLD responses to broadband noise in 62 individuals with clinically normal audiometric thresholds. We demonstrate robust individual and group responses to a broadband noise across structures in the auditory pathway. In line with animal models, we show a significantly increased BOLD response to stimulus onset in individuals with high noise exposure compared to those with low noise exposure in all auditory structures assessed. We also show a trend towards individuals with high noise exposure exhibiting a greater sustained BOLD response. |
| 3787 | Computer 108
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7T functioanl MRI reveals frequency-dependent responses during vibrotactile stimulation at somatosensory cortex |
1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, 2College of Biomedical Engineering & Instrument Science，Zhejiang University, Hangzhou, China, 3Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China, 4The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China |
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To investigate whether the brain can directly encode different vibrotactile frequencies, we made a MR-compatible lab-designed vibrotactilestimulator to presented pulse stimuli on middle finger (with a frequency difference in the same duration) andusing BOLD fMRI to explore the effectsofvibrotactilefrequencyin somatosensory cortex with 7T MR research system. The results showedthat the lab-designed MR compatible vibrotactile stimulator could elicit BOLD responsesin the somatosensory cortex. Also, the BOLD response was frequency-dependent with the peak at 6Hz. |
| 3788 | Computer 109
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Effect of cue induced craving on brain morphometry and function in adolescent inhalant users |
1Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India, 2Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 3National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi, India |
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Inhalants are legal, inexpensive substances that are often abused by adolescents. This study compared the BOLD changes in brain associated with cue-induced craving in adolescent inhalant users (n=13) and healthy controls (n=12) to elucidate the neural mechanisms associated with cue-induced craving. The cases exhibited an increased activation of superior occipital gyrus, inferior parietal lobule, cingulate gyrus, thalamus, and culmen and a decreased activation of insula as compared to control group for craving cues. Visual cue reactivity was associated with activation of the areas responsible for visual perception, visuo-spatial attention and working memory, control and motivation. |
| 3789 | Computer 110
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The faster the better: onsets of pre-SMA and right inferior frontal activations predict successful stopping in a stop-signal task |
1National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3University of Toronto, Toronto, ON, Canada, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland |
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Using fast fMRI (whole-brain 10 Hz sampling), we revealed BOLD activities in the pre-SMA and right inferior frontal gyrus are activated faster for successful than for unsuccessful stopping. |
| 3790 | Computer 111
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Dopaminergic modulation of reasoning ability in non-demented Parkinson’s disease |
1Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China, 2School of Psychology, Capital Normal University, Beijing, China |
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Patients with Parkinson's disease (PD) are more likely to suffer cognitive decline and experience difficulties in daily living requiring reasoning including medication use, financial management, and nutrition and food preparation even at early stage of the disease.1,2 The present study aimed to explore L-dopa modulation on the reasoning ability in PD. Twenty non-demented PD underwent reasoning fMRI examinations OFF-medication and ON-medication. It was found that ON-medication PD patients exhibited improved reasoning performance and recruited the striatum compared to OFF-medication. The current findings suggest that L-dopa treatment mediated the neural activity in the striatum and further improved the behavior performance. |
| 3791 | Computer 112
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Brain-to-Brain Interaction and Entanglement |
1Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NJ, United States |
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Recognizing that the coherence of proton nuclear spin ensembles in dyadic brains is periodically enforced by the RF excitation pulses so that superposition states may be embedded in MR signals, the mathematical language of quantum theory is utilized to describe a dyadic fMRI experiment. Within this platform, the data-driven dyadic communication model, two coupled three-layer neural networks, predicts not only brain-to-brain interaction operations but also entanglement operations which might profoundly expand our understanding of human social communication. |
| 3792 | Computer 113
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Neurocognitive modifications associated with auditory perception in children and adolescent group in early and late blind subjects: A functional magnetic resonance imaging study |
1Neurology, All India Institute of Medical Sciences, New Delhi, India, 2All India Institute of Medical Sciences, New Delhi, India |
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Perceiving the world without any visual cue in |
| 3793 | Computer 114
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A combined task based fMRI connectivity and VBM study to lateralization of memory function in pre-and post-surgery mesial temporal lobe epilepsy patients. |
1Neurology, AIIMS, New Delhi, India, 2NMR, AIIMS, New Delhi, India, 3Neurosurgery, AIIMS, New Delhi, India |
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Patients with temporal lobe epilepsy (TLE) have associated cognitive dysfunction and memory impairment on anterior temporal lobe resection (ATLR). Semantic verbal memory reorganization was investigated using functional connectivity (FC) and VBM in pre-and post-operative TLE subjects and healthy controls. Reduction in GM concentration was observed in left temporal lobe post-operatively in comparison to pre-surgery session and healthy controls. Semantic verbal memory components revealed increased FC in right hemisphere with decreased memory scores at follow-up (6 months post-surgery) compared to that of pre-surgery, indicating damage in the medial temporal region due to surgical resection resulting in semantic verbal memory network dysfunction. |
| 3794 | Computer 115
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Working memory deficits in childhood cancer survivors: an fMRI study |
1Stony Brook Medicine, Stony Brook, NY, United States, 2Stony Brook Children's Hospital, Stony Brook, NY, United States |
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Little is known about the neural correlates of cognitive deficits in chemotherapy treated survivors of childhood cancer. We used event related fMRI to study working memory in childhood cancer survivors. Subjects underwent an n-back task to test working memory function. Patients showed reduced BOLD signal on correct responses compared to controls in the anterior cingulate, posterior cingulate, and sensory association cortices. Patients showed increased activation on error trials in the angular gyrus and superior parietal lobule. The affected brain regions are known to be involved in memory function, reward, motor planning and motivation. |
| 3795 | Computer 116
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Detecting CBF to Explore Verbal Memory Impairment Mechanisms in Subcortical Stroke Patients |
1Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 3GE Healthcare MR Research, Beijing, China |
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In order to explore the neural substrates underlying verbal memory (VM) impairment in subcortical stroke patients, we recruited sixty patients with chronic subcortical stroke and sixty normal controls. 3D-ASL imaging was used to measure the resting-state values of voxel-wise cerebral blood flow (CBF) and the alterations of functional covariance network were detected. In this study, the different CBF levels in the stroke patients and the normal controls, as well as the close correlation between the CBF values and the VM scores, indicate that the VM impairment in stroke patients may be associated with the disconnection of frontal-lobe network. |
| 3796 | Computer 117
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Influence of smoking cessation treatment by varenicline to brain—a resting-fMRI study |
1Radiology, Beijing Chao-Yang Hospital, Beijing, China, 2School of biomedical engineering, Capital medical university, Beijing, China, 3Clinical research centre, Beijing Chao-Yang Hospital, Beijing, China, 4HC NEA DI MR Siemens Healthcare Ltd, Beijing, China |
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This study investigated the activation changes of brain regions in smokers before and after cessation treatment using a resting state fMRI. The results demonstrated that treated smokers will have improved functions of brain regions related to emotion and memory after using varenicline. This improvement is not only the direct benefit of quitting smoking, but also helps quitters cope with the discomfort and negative emotions of quitting. All subjects showed a decrease in smoking addiction and withdrawal response, suggesting that varenicline can help quitters maintain their withdrawal status. |
| 3797 | Computer 118
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Dynamic up- and down-regulation of large-scale cortical networks during task-on and task-off periods. |
1Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway, 2NORMENT Centre of Excellence, University of Oslo, Oslo, Norway, 3Department of Education, The Arctic University of Norway, Tromsø, Norway, 4Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway, 5Institute of Psychology, Univeristy of Oslo, Oslo, Norway, 6Department of Radiology, Haukeland University Hospital, Bergen, Norway, 7Department of Physics and Technology, University of Bergen, Bergen, Norway, 8Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway, 9Division of Psychiatry, Haukeland University Hospital, Bergen, Norway |
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This study was intended to capture the dynamics of networks up- and down-regulation over time, with focus on the extrinsic mode network (EMN) and the default mode network (DMN), using functional magnetic resonance imaging (fMRI). Finite impulse response function (FIR) featured in the SPM software package was used to estimate the BOLD response. The results featured initial rapid activation of EMN in task-periods, while DMN began to drift towards up-regulation already by the end of the task-period. |
| 3798 | Computer 119
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Abnormal local spontaneous brain activity revealed by resting-state fMRI as a biomarker for predicting radiation-induced neurocognitive dysfunction in patients with nasopharyngeal carcinoma |
1Department of Medical Imaging, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China, 2GE Healthcare, MR Research China, Beijing, China, 3Department of Radiology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China |
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In this study, we hypothesize that radiation therapy induce longitudinal neurocognitive dysfunction in patients with nasopharyngeal carcinoma. To verify this hypothesis, resting-state functional magnetic resonance imaging (fMRI) was used to detect the local spontaneous brain activity in 38 patients with nasopharyngeal carcinoma 20 healthy controls at the baseline and follow-up examinations. The changes in brain activity at the early delayed stage after radiation therapy are then used to predict the brain functional impairment at a later stage. The results showed that radiation therapy may induce significant changes in reginal homogeneity in the brain, and such changes at early delayed stage may serve as a potential biomarker for predicting neurocognitive dysfunction at a later stage. |
| 3799 | Computer 120
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Abnormalities of intrinsic regional brain activity at resting state in schizophrenia: a meta-analysis of resting-state functional MRI |
1Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou, China, 2Department of Radiology, Six Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, 3Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou, China, 4School of Psychology, Institute of Brain Research and Rehabilitation (IBRR), Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou, China |
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Evidences of abnormal intrinsic brain activity in schizophrenia (SZ) are inconsistent demonstrated by previous studies. A meta-analysis that explored the differences of the ALFF between SZ patients (including first episode [FE] and chronic patients) and healthy controls were conducted. FE patients demonstrated decreased ALFF in the DMN and increased in the putamen, VN (visual network). Chronic patients showed decreased ALFF in the DMN, sensorimotor network, and VN and increased in the salience network, frontotemporal regions. Aberrant regional brain activity during the initial stage and widespread damage with the progression of disease contributes to understand the progressive pathophysiology feature of SZ. |
| 3800 | Computer 121
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Graph theoretic analysis of language sub-networks in Arabic-English bilingual patients undergoing fMRI for pre-surgical planning |
1Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Kennedy Krieger Institute, Baltimore, MD, United States |
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Task fMRI is routinely performed on patients for pre-surgical planning to localize critical components of the language network and assess hemispheric language dominance. However, the cortical representation of language in bilingual patients (those who are fluent in more than one language) is more complex than in monolinguals, and may involve overlapping but distinct sub-networks. The focus of our current study is to assess the functional connectivity strength of language networks derived from task fMRI activation maps obtained using paradigms performed in both primary native (L1) and secondary (L2) languages in a group of Arabic-English bilingual patients. |
| 3801 | Computer 122
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Altered connectivity following olfaction fMRI in Patients with Parkinson’s Disease: A comparative study using two different odors |
1Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Neurology, All India Institute of Medical Sciences, New Delhi, India, 3National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi, India |
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Olfactory impairments are one of the cardinal non-motor symptoms in Parkinson’s Disease (PD). Functional Connectivity analysis was carried out for olfaction task with floral fragrance (smell 1) and citrus fragrance (smell 2) on 10 PD patients (9M/1F, mean age ± SD=57.7±5.6 years). Main effects depicted heterogeneous connectivity and differential lateralization for both the smells. Amygdala and the thalamus were affected for both the smells in patients with PD and may be attributed to the pathology. Olfaction specificity for hippocampal connectivity in floral smell and for orbitofrontal, insula and anterior cingulate in citrus smell suggest differential recruitment of cognition linked areas. |
| 3802 | Computer 123
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Disrupted functional connectivity strength in overactive bladder syndrome patients |
1Beijing Chaoyang Hospital, Beijing, China |
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A dysregulation of the brain-bladder control network has been revealed by the functional brain imaging studies. However, the brain functional connectivity strength (FCS) of OAB still remains unclear. Our study investigated the changes of intrinsic whole brain functional connectivity pattern in OAB using FCS. Patients with OAB have impaired pattern of FCS, which shows abnormal short-range and long-range FCS in brain regions associated with brain-bladder network. Behavioural treatments of the OAB based on fMRI may provide new sight into clinical practice. |
| 3803 | Computer 124
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Neuropsychological Assessments and ALFF across Multiple Categories of Carotid Artery Stenosis |
1National Tsing Hua University, Hsinchu, Taiwan, 2Taipei Medical University, Taipei, Taiwan, 3Chang Gung University, Taoyuan, Taiwan, 4Chang Gung Memorial Hospital, Taoyuan, Taiwan |
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We explored the relationship between neuropsychological tests and ALFF based on three types of patients with carotid artery stenosis: unilateral stenosis, unilateral occlusion and bilateral stenosis. We found that patients with occlusion and bilateral stenosis had stronger ALFF than controls, but the neurophysiological results did not match the ALFF outcomes. |
| 3804 | Computer 125
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Altered resting-state functional connectivity in patients with cervical vertigo |
1Renmin Hospital of Wuhan University, Wuhan, China, 2GE Healthcare China, Beijing, China |
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As a pioneering work to cervical vertigo in functional connectivity perspective, in some extent, we discovered the potential specific spatiotemporal neuronal functional mechanisms alteration, and altered functional connections were correlated to clinical scale scores. These findings might support complementary evidence for its clinical cognition. |
| 3805 | Computer 126
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Zero TE based screening for transcranial MR guided focused ultrasound |
1hmCINAC, University Hospital HM Puerta del Sur, Móstoles, Spain, 2GE Healthcare, Madrid, Spain, 3Neuroimaging, hmCINAC, Móstoles, Spain |
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The high acoustic impedance of the skull limits the performance of tissue ablation applications with tcMRgFUS. Skull characterization is currently based on CT. Zero echo time (ZTE) images could represent a safer alternative in this matter. CT and ZTE images were acquired in sixteen essential tremor patients that underwent tcMRgFUS. Several skull measures were obtained for both images. ZTE and CT based metrics were strongly correlated. Furthermore skull thickness and the skull density ratio were able to predict the efficiency of the treatment. In conclusion, ZTE based measures are able to determine the suitability of a tcMRgFUS candidate. |
| 3806 | Computer 127
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Sacroiliac joint ablation in a chronic swine model using MRgFUS |
1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Orthopedic Surgery, University of California San Francisco, San Francisco, CA, United States, 3Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States |
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There is evidence that MRgFUS might be a very safe and effective minimally invasive technique to treat sacroiliac joint pain caused by arthritis and other degenerative changes. This study in a chronic swine model demonstrated safety and effectiveness of MRgFUS sacroiliac joint ablation and precise ablation of the posterior sacral nerve supply with MRgFUS. |
| 3807 | Computer 128
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Temporal changes in multiparametric imaging features of the prostate gland following MRgFUS ablation |
1Department of Radiology, Stanford University School of Medicine, Stanford, CA, United States, 2Stanford University, Palo Alto, CA, United States, 3Department of Urology, Stanford University School of Medicine, Stanford, CA, United States |
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Magnetic resonance guided high intensity focused ultrasound (MRgFUS) can be used for focal therapy of prostate cancer. After treatment, these men remain in active surveillance. Effective monitoring of these men requires an understanding of the expected MRI appearance of the prostate after MRgFUS. Twenty-three patients treated with MRgFUS for focal, intermediate risk MR imaging-visible prostate cancer were followed with serial MRI for 6-24 months. We describe temporal changes in the qualitative and quantitative multiparametric imaging features of the prostate gland post-MRgFUS ablation to aid radiologists to better interpret follow-up examinations to detect residual or new disease. |
| 3808 | Computer 129
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Longitudinal assessment of Focused ultrasound (FUS) induced Blood-Brain Barrier (BBB) opening in the non-human primate under 7T MRI |
1Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, Hangzhou, China, 2College of Biomedical Engineering & Instrument Science，Zhejiang University, Hangzhou, China, Hangzhou, China, 3School of Medicine, Department of Electrical Engineering, Chang Gung University, Taoyuan, Taiwan, Taiwan, China |
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Microbubble-mediated focused ultrasound can noninvasively induce reversible blood-brain barrier (BBB) opening in both rodents and non-human primates. However, it remains unclear whether FUS-induced BBB opening is accompanied by neuromodulation. Here we longitudinally characterized the duration and the functional effects of FUS-induced BBB opening by measuring changes in contrast-enhanced T1-weighted images (T1-WIs) and blood-oxygen-level dependent (BOLD) responses, respectively. The results show that BBB recovered at 6.5h post-FUS exposure. The blood-oxygen-level dependent (BOLD) changes during the visual stimulus pre- and post- FUS exposure didn't show similar change trend in both hemispheres. The results of fMRI-guided FUS may contribute to the development of FUS-induced BBB opening for clinical applications. |
| 3809 | Computer 130
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Rapid MR-guided-HIFU using Convolution-based Reconstruction and Parallel Imaging (CORE-PI) |
1Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel |
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A novel reconstruction method for accelerated Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) thermometry is presented. This method utilizes multi-coil acquisition, k-space undersampling and the recently introduced Convolution-based Reconstruction for Parallel Imaging (CORE-PI) technique. The proposed method utilizes data sparsity in the Stationary Wavelet Transform (SWT) domain. It is a parameter-free, non-iterative and calibrationless method. Retrospective experiments with in-vivo data from clinical human prostate ablation treatments show that the proposed method produces accurate temperature maps from two-fold and three-fold subsampled k-space data. The method is therefore suitable for real time application. |
| 3810 | Computer 131
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Enhancement of the HIFU thermal effect in ex-vivo kidneys using a new class of endovascular sono-sensitizers |
1Image Guided Interventions Laboratory, Faculty of Medicine, University of Geneva, Geneva, Switzerland, Geneva, Switzerland, 2Radiology Department, University Hospitals of Geneva, Geneva, Switzerland, Geneva, Switzerland, 3University of Avignon, CBSA-IBMM (UMR5247), Avignon, France, Avignon, Switzerland, 4Department of Radiology and Medical Informatics, University of Geneva, Switzerland, Geneva, Switzerland, 5Research and Development Laboratory, Visceral and Transplantation Service, University Hospital Geneva, Geneva, Switzerland., Geneva, Switzerland, 6Sorbonne Universités, UPMC Univ Paris 06, CNRS, INSERM, Laboratoire d’Imagerie Biomédicale (LIB), F-75006, Paris, France, Paris, Switzerland |
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Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) is a promising approach for the non-invasive ablation of localized tumors. Ablation of highly perfused tumors is challenging due to the heat sink effect. We developed a new concept of endovascular liquid core micro-droplets, used as sono-sensitizers for the enhanced absorption of the HIFU beam. We demonstrated the improvement of the HIFU thermal effect after adjunction of sono-activable micro-droplets in the perfusion fluid of freshly excised viable pig kidneys. Temperature maps were computed using the PRFS method to prove the enhancement of thermal contrast. |
| 3811 | Computer 132
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Novel Acoustic Coupling Design to Improve MR Imaging Guidance for Focused Ultrasound Surgery |
1Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Department of Mechanical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 3Department of Biomedical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 4Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 5Department of Chemical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 6Department of Radiology, University of Virginia, Charlottesville, VA, United States |
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We explore the feasibility of an acoustic coupling medium that is invisible to both T2-weighted anatomical scans and MR thermometry scans during MR-guided focused ultrasound surgery and yet still preserves the cooling and acoustic coupling functions normally provided by water. |
| 3812 | Computer 133
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Detecting T1-based Signal Reduction in Focused Ultrasound Heating of Bone using a 3D Spiral Ultra-Short Echo Time Sequence |
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Autism and Developmental Medicine Institute, Geisinger Health System, Danville, PA, United States, 3Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States |
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MR-guided Focused Ultrasound (MRgFUS) is used transcranially to ablate brain tissue for the treatment of neurological diseases. Temperature monitoring of the skull is desired for increasing treatment safety and efficacy. Proton resonance frequency shift MR fails to detect heating in the cortical bone of the skull. T1-based MR thermometry uses T1 mapping to observe a linear increase in T1 with temperature but requires long acquisitions. We demonstrate a new thermometry method dependent on the linear relationship between signal magnitude from a T1-weighted 3D Spiral Ultra-short Echo Time sequence and test it across three scanners in multiple trials. |
| 3813 | Computer 134
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Assessing the effect of pre-focal fat on the feasibility of delivering MR guided high intensity focused ultrasound (MRgHIFU) treatment of intra-pelvic tumors |
1CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden Hospital, London, United Kingdom, 2Therapeutic Ultrasound, The Institute of Cancer Research, London, United Kingdom |
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Models were used to simulate the pre-focal tissue distributions encountered when treating intra-pelvic tumors with magnetic resonance guided high intensity focused ultrasound (MRgHIFU). Focal peak temperature and thermal dose volumes were considerably affected by depth and fat thickness. Exposures of 300 W for ≥20 s (≥6 kJ) were required to generate measurable 30EM dose contours 8 cm deep (6 cm pre-focal fat). The relative distributions of fat and muscle layers had minimal effect on focal heating, but influenced location of potentially damaging pre-focal heating. MRgHIFU treatments to deep-seated intra-pelvic tumors require methods for improving dose delivery at depth. |
| 3814 | Computer 135
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Registration of In Vivo MR images to Volumetric Histopathology |
1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Department of Surgery, University of Utah, Salt Lake City, UT, United States, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States |
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As MR guided focused ultrasound (MRgFUS) treatments evolve to treat oncological diseases, the ability to accurately assess the efficacy of treatment is critical. Although there are several MR metrics proposed for assessing MRgFUS treatments, they have not been rigorously validated against gold standard histopathology treatment assessment. Current validation studies that register MR to histopathology do not comprehensively account for all deformations during histological processing. We present a rigorous MR to histopathology registration pipeline that estimates deformation at every step that can be used to accurately validate the efficacy of oncological MRgFUS treatment. |
| 3815 | Computer 136
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Transcranial focused ultrasound localization in Money at 3T |
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China |
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Focused ultrasound has been a fast developing technology for non-invasive neuromodulation. Monkey is a good animal model for studying the mechanism of focused ultrasound on neural network. However, the ultrasound beam would be greatly attenuated and distorted by the monkey skull, making the precise focal localization a crucial step. MR-ARFI with little thermal effect was an attracting tool for focus localization. In this study, we investigated the transcranial MR-ARFI in monkey at 3T system. With high performance of the customer designed monkey head coil and the strong gradient system, reliable and repeatable results were obtained. |
| 3816 | Computer 137
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Longitudinal Registration for Voxel-wise Correlation of MRgFUS Treatment Assessment Metrics |
1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Department of Surgery, University of Utah, Salt Lake City, UT, United States, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States |
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The acute assessment of MRgFUS therapies with metrics such as thermal dose and contrast-enhanced (CE) imaging have been shown to under- or over-estimate the final ablation lesion as assessed by delayed imaging or histological outcomes. The aim of this study is to longitudinally register MRgFUS treatment images to a final lesion outcome as determined by CE-T1w imaging three days post-treatment for voxel-wise analysis of these errors. MR thermometry (MRTI), cumulative thermal dose (CTD), and acute CE-T1w images are co-registered to Day 3 CE-T1w with millimeter accuracy and assessed for their predictive value. |
| 3817 | Computer 138
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Fast 3D MR thermometry using echo-shifted sequence with parallel acquisition acceleration |
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, CAS, Shenzhen, China |
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A high-precision, fast MR thermometry is always preferred for HIFU monitoring. However, the coverage of MRT is also important for the safety concern as the unwanted burn usually takes place in the tissue interface which might be far away from the focal area. In this work, we combined 3D echo-shifted GRE sequence with 2D parallel imaging acceleration to implement a fast 3D MRT. |
| 3818 | Computer 139
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A Principal Component Analysis based Multi-baseline Phase Correction Method for PRF Thermometry |
1Siemens Medical Solutions USA Inc., Malvern, PA, United States, 2Siemens Healthcare GmbH, Erlangen, Germany, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 4Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States |
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The use of Proton Resonance Frequency (PRF) based thermometry with thermal therapy procedures is indispensable. Variation in background phase due to motion related changes in B0 is a major source of inaccuracy in PRF thermometry. In this work we propose a novel Principal Component Analysis (PCA) based multi-baseline phase correction approach. We compare this approach with two existing methods using in-vivo human brain and heart data, and demonstrate significant reduction in bias as well as variance of temperature difference estimates. The proposed approach may increase the accuracy of PRF thermometry in or near moving organs, and hence result in improved clinical outcome. |
| 3819 | Computer 140
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Development of 2D Cartesian, radial and UTE MP2RAGE sequences for fast T1 mapping: application to MR thermometry |
1CNRS - Univ. Bordeaux, CRMSB UMR 5536, Bordeaux Cedex, France |
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A surrogate strategy to the Proton Resonance Frequency technique that fails when short T2* tissue are present is the measurement of the longitudinal relaxation times T1. In order to monitor temperature in real-time, a 2D version of the Magnetization Prepared 2 Gradient Echo (MP2RAGE) sequence has been developed, and the cartesian encoding has been replaced by radial ones to obtain an ultra-short Echo Time (UTE). This enabled to measure T1 of short T2*-phantoms and to perform MR thermometry every 8s over a wide range of temperatures and consequently of T1. |
| 3820 | Computer 141
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Active Tracking-based cardiac triggering of MR thermometry for MRI-guided cardiac ablation |
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Siemens Healthcare GmbH, Erlangen, Germany, 3MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 4Imricor Medical Systems, Burnsville, MN, United States |
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MR thermometry can be used for MRI-guided cardiac ablations, but ECG-triggering is not always effective. We propose to use the Active Tracking (AT) functionality included in the catheter to prospectively trigger the thermometry measurements. Modules measuring the position of the AT microcoil were interleaved with a thermometry sequence, which were repeated until a trigger condition is detected. Experiments showed successful triggering in a beating heart phantom, with a temperature stability of 1.12±0.36°C. For in-vivo interventional application, respiratory motion will need to be taken into account. |
| 3821 | Computer 142
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A flexible 11-channel coil array for MR-guided high-intensity focused ultrasound (HIFU) studies on rabbit leg muscle at 3 T |
1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2High Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, Chengdu, China, 3Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 4UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States |
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Signal-to-noise ratio (SNR) of the radio frequency (RF) receive coil array is a critical factor affecting the accuracy of temperature measurement in MR-guided high-intensity focused ultrasound (HIFU) for local heating. In this work, a flexible 11-channel coil array was designed, constructed and evaluated for MR-guided HIFU studies on rabbit leg muscle at a 3 T MRI scanner. Compared to a commercial available 4-channel flexible coil array, the dedicated 11-channel coil array provides improved performance in SNR, parallel imaging capability, and the accuracy of temperature measurement. |
| 3822 | Computer 143
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Comparison of Cartesian MR thermometry approaches for focused ultrasound brain applications |
1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Siemens Healthineers, Baltimore, MD, United States, 3Siemens Healthineers, Boston, MA, United States, 4Siemens Healthineers, Salt Lake City, UT, United States |
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Magnetic resonance guided focused ultrasound using MR thermometry (MRT) for therapy guidance is a promising thermal therapy for a wide range of neurological disorders. The current MRT method acquires a single 2D slice with low readout bandwidth to increase SNR and MRT precision, compensating for the fact that the body coil is used to receive during treatments. In this work we investigate trade-offs between 2D and 3D GRE and EPI approaches of MRT for brain FUS applications. A comparison between using the body coil and two 4-channel flex coils is also performed. |
| 3823 | Computer 144
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Improved MR thermometry using saturation bands to suppress water signal |
1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Siemens Healthineers, Baltimore, MD, United States, 3Siemens Healthineers, Salt Lake City, UT, United States, 4Siemens Healthineers, Boston, MA, United States |
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MR guided focused ultrasound (MRgFUS) treatments are routinely monitored by MR thermometry (MRT). Image quality and MRT precision can be significantly degraded by water motion in the water bath used to couple the FUS transducer to the target tissue. This problem is especially challenging when the water bath surrounds the target tissue. In this work we investigate the use of saturation bands to suppress the unwanted signal in dedicated breast and brain MRgFUS systems. It is shown that using saturation bands to suppress signal from the water bath significantly reduces artifacts and improves MRT precision with potentially shorter scan times. |
| 3824 | Computer 145
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k-space MR Thermometry Using k-space Energy Spectrum Analysis |
1Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 3Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 4Department of Physics, Soochow University, Taipei, Taiwan |
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The goal of this work was to perform MR thermometry in the k-space domain, as opposed to the image domain, on the premise that a k-space approach might be better suited at capturing spatial trends. The method relies on the fact that spatial gradients in temperature cause k-space shifts in signals for heated materials. Traditional proton resonance frequency (PRF) thermometry was also performed, for validation purposes. |
| 3825 | Computer 146
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A Dual-Echo bSSFP Imaging Method for Proton Resonance Frequency-Based Thermometry and Analysis of Phase Behavior in bSSFP |
1School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of |
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Proton resonance frequency thermometry is useful to estimate temperature change that is proportional to the resonance frequency change. In this study, we propose a dual-echo bSSFP thermometry method that generates a high intensity signal and linear phase to the frequency shift. Off-centered acquisition in the balanced steady-state free precession creates an imperfect linear phase with respect to the frequency shift. The dual-echo acquisition method compensates for the phase nonlinearity and generates phase information that is linearly proportional to the frequency shift. This phase linearization makes it possible to accurately measure the proton resonance frequency shift caused by temperature change. |
| 3826 | Computer 147
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Design, evaluation and application of a 16-channel Frequency Synthesizer Module for Thermal Magnetic Resonance |
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2Beijing Deepvision Technology Co., Ltd., Beijing, China, 3Physikalische Technische Bundesanstalt (PTB), Berlin, Germany, 4IHP – Leibniz-Institut für innovative Mikroelektronik, Frankfurt (Oder), Germany, 5Institute of Computer Science, Humboldt-Universität zu Berlin, Berlin, Germany, 6Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany, 7MRI.TOOLS GmbH, Berlin, Germany |
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Thermal Magnetic Resonance makes use of the physics of the radio frequency fields applied at ultrahigh field magnetic resonance imaging. While UHF-MRI enables measuring temperature in vivo, highly localized power deposition can be achieved by interfering RF waveforms with a shortened wavelength. This constitutes a means for supervised in vivo temperature modulation. The number of RF signals and the signals’ properties greatly affect the heating performance. In this work, a 16-channel frequency synthesizer module was developed as an RF signal source for Thermal MR. Preliminary experiments were conducted to demonstrate that the proposed module is suitable for Thermal MR. |
| 3827 | Computer 148
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Ultra-Wideband Self-Grounded Bow-Tie Antenna Building Block for Thermal Intervention, Diagnostic MRI and MR Thermometry at 7.0 Tesla |
1Berlin Ultrahigh Field Facility, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany, 3MRI.TOOLS GmbH, Berlin, Germany, 4Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden, 5Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany |
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A compact resonator antenna for broadband thermal intervention, diagnostic proton (1H) and fluorine (19F) imaging and MR-Thermometry was developed for operating at 7.0T MRI. The antenna is based on the concept of a self-grounded bow-tie (SGBT) antenna to enable thermal intervention frequencies ranging from 250MHz to 516MHz. The self-grounded bow-tie resonator antenna is smaller and lighter compared to previous dipole-antenna designs, enabling a high-density multi-channel array. The proposed antenna is demonstrated to be suitable for diagnostic imaging, thermal intervention, and MR thermometry. |
| 3828 | Computer 149
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Power Considerations for Radiofrequency Applicator Concepts for Thermal Magnetic Resonance Interventions in the Brain at 297 MHz |
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2MRI.TOOLS GmbH, Berlin, Germany, 3Clinic for Radiation Oncology, Charite University Medicine, Berlin, Germany, 4Biomedizinische Magnetresonanz, Physikalisch Technische Bundesanstalt, Berlin, Germany, 5Experimental and Clinical Research Center (ECRC), joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany |
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There is a pressing need to implement Thermal MR therapies in the brain, particularly to sensitize treatment of aggressive cancers like glioblastoma multiforme. Given the high power transmission regime of Thermal MR therapies, it is crucial to understand the engineering constraints affecting RF power losses, since inaccurate estimates could compromise the efficiency and precision of the therapy. Here we conducted a thorough simulation of five RF applicator designs, using realistic loss estimates of material and electrical components, and considering antenna design, position and coupling. Results from simulated and patient-derived data underscore that clinical requirements must balance with practical engineering constraints. |
| 3829 | Computer 150
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Flip angle optimization and in vitro demonstration of 2D DESPOT1-based fat thermometry |
1University Medical Center Utrecht, Utrecht, Netherlands |
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During MR-HIFU ablations, fat MR thermometry (MRT) is needed for monitoring temperature in adipose tissues (both in target regions and in subcutaneous fat in the near field of the ultrasound beam). It can be based on T1 mapping calculated with 2D-DESPOT1 method and corrected for the FA variation over the slice profile. However, difficulties arise in the choice of 2 flip angles optimized for the whole expected range of T1s in fat MRT. We identify the optimal settings through simulation and demonstrate the feasibility of fat MR thermometry through 2D DESPOT1 sequences in phantom experiments. |
| 3830 | Computer 151
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Performance of an aerosol jet-deposited wireless resonant marker: in vitro temperature measurements and in vivo visualization |
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Quest Integrated, Kent, WA, United States, 3Graduate Program in Bioengineering, UC Berkeley-UCSF, Berkeley, CA, United States, 4Bioengineering and Therapeutic Sciences, University of California, Berkeley, Berkeley, CA, United States, 5Radiology, Stanford University, Stanford, CA, United States, 6Electrical Engineering, Stanford University, Stanford, CA, United States |
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Endovascular catheter-based procedures under MRI can be challenging as standard fabrication methods for markers are rigid and bulky, and new microfabrication methods need more analysis on their tracking characteristics. We analyzed a wireless resonant circuit tracking marker that was printed using aerosol jet deposition on a polymer catheter. In a phantom, we acquired bSSFP sequences and a B1+ map, and measured temperature using probes and MR thermometry. In vivo, in the carotid arteries, we acquired GRE sequences and a B1+ map. The marker demonstrated good signal, with minimal temperature increases, suggesting that these markers have good tracking characteristics. |
| 3831 | Computer 152
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Motion-Adaptive Temporal Resolution for Radial Real-Time Imaging at a Low-Field MR-Linac |
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany, 5Department of Radiation Oncology, University Hospital of Heidelberg, Heidelberg, Germany |
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Hybrid MRI linear accelerators (MR-linacs) enable real-time image guidance during radiotherapy. Under real-time MRI, a compromise must be found between spatio-temporal resolution and SNR, whereas to precisely track tumour position, both should be maximised. The presented method implements a motion-adaptive image reconstruction based on a golden-angle radial acquisition scheme. This allows producing SNR-optimised images under periods of small motion and images optimised for temporal resolution when motion is larger. The technique was implemented at a low-field MR-linac (0.35T) to image a free-breathing volunteer and a motion phantom. |
| 3832 | Computer 153
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Interleaved White Marker Contrast with bSSFP Real-Time Imaging for Deep Learning based Needle Localization in MR-Guided Percutaneous Interventions |
1Siemens Healthcare, Erlangen, Germany, 2TU Dortmund, Dortmund, Germany, 3Hannover Medical School, Hannover, Germany |
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Automatic localization of needles in real-time images can facilitate MR-guided percutaneous interventions. It enables automatic slice repositioning and targeting support and, thus, allows for faster workflows. The improvement of deep learning based passive needle tracking by using both, anatomical and positive contrast images as input was investigated. A prototype bSSFP sequence for interleaved acquisition of k-space lines for conventional and positive contrast with Cartesian readout was implemented and evaluated ex-vivo and in-vivo. The U-Net segmentation algorithm showed superior performance when using both contrasts. In conclusion, this method is a promising approach for robust needle localization in real-time interventional workflows. |
| 3833 | Computer 154
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A simple freehand technique for MRI-guided needle localization of suspicious breast lesions |
1radiology, Renji Hospital, Medical College of Shanghai Jiao Tong University, shanghai, China |
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A total of 273 patients who received needle localization with a bare-hand technique for suspicious breast lesions by using 1.5 T MR-guided were included in our study. The puncture method was similar to CT-guided needle localization of lung nodule. The success rate of localization was 100% (273/273). Procedure time of all the cases ranged from 5 to 30 min (mean, 14.3 min). Our MRI-guided bare-hand needle localization of suspicious breast lesions is a handy, safe, rapid, and accurate interventional method. The lesions that are located at axillary region of breast，areola area, and the special area near the chest wall can all be precisely localized. |
| 3834 | Computer 155
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Highly Undersampled Radial Passive Marker Tracking with Phase-only Cross-Correlation (POCC) for Real Time Image Guidance |
1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Interventional Systems GmbH, Kitzbuehel, Austria |
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Marker tracking with phase-only cross correlation (POCC) is an efficient technique to localize instruments during percutaneous MR-guided interventions in closed-bore MR systems. Unfortunately, POCC is time-consuming, as additional marker images need to be continuously acquired. Here, we present a drastically accelerated POCC sequence that uses radially undersampled images to detect the passive marker. With a modified POCC algorithm this sequence can detect marker movements within less than 108ms thus providing a very fast position feedback. The precision of the POCC sequence was evaluated in phantom measurements, and a possible in vivo targeting scenario was demonstrated in a volunteer. |
| 3835 | Computer 156
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Radial Simultaneous Multi Slice Imaging for Marker Tracking |
1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany |
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The phase-only cross correlation (POCC) algorithm efficiently and accurately detects passive MR markers used as needle guides. In a POCC sequence the marker is automatically detected in two cross-sectional images to continuously visualize the planned needle trajectory during motion. Image acquisition of the marker, however, is very time consuming which degrades the temporal resolution. Here, it is shown that two simultaneously acquired, highly undersampled radial images - together with the consideration of the point-spread-function in the POCC algorithm - can track the marker at substantially shorter acquisition times. |
| 3836 | Computer 157
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MRI Driven Augmented Reality Image-Guidance Platform for Myocardial Cell Delivery |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Schulich Heart Research Program, Sunnybrook Research Institute, Toronto, ON, Canada, 3McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON, Canada |
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Myocardial infarction is a leading cause of heart failure, a condition with a 5-year mortality rate of ~50%. Current HF management techniques aim to slow disease progression rather than improve function. Cardiac regenerative medicine through cell-based approaches offers the potential to repopulate non-contractile scar tissue. However, regions of scar are not well delineated during the cell-delivery procedures, and accurate cell placement is vital to realize positive outcomes from therapy. We aim to develop a novel integrative image-guidance solution combining MRI for myocardial scar characterization with augmented reality via a head-mounted display to visualize critical MRI information intraoperatively and guide delivery. |
| 3837 | Computer 158
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Phantom Study of Novel Biopsy Needle and Assisted Robotic System Designed for Prostate Biopsy Procedure under MRI |
1Biomedical Engineering, Bogazici University, Istanbul, Turkey |
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In this study, a novel MRI guided prostate biopsy device was designed, produced and tested under MRI. In this scope, a MRI compatible, remote controlled, transrectal biopsy delivery system, a MRI compatible biopsy gun, a MRI compatible, biopsy needle which can be tracked under MRI, and a computer based control unit were designed and a prototype was produced. The robotic prostate biopsy device prototype was tested under MRI with in-vitro experiments using a commercially available prostate phantom. |
| 3838 | Computer 159
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Ten Minutes for the Brain to Settle: an In-vivo Investigation of Positional Brain Shift |
1Computer Science and Informatics, Cardiff University, Cardiff, United Kingdom, 2School of Engineering, Cardiff University, Cardiff, United Kingdom, 3Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom |
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Positional brain shift (BS), as the physiological sagging of the brain under the effect of gravity, has a magnitude that is comparable to the accuracy of neuronavigational systems. It is a complex interaction of gravity, anatomical boundaries and tissue mesostructure. A comprehensive investigation of such deformation is needed. This study aims to provide a rich set of volumetric measures to infer the pattern of deformation as well as the time evolution of positional BS. Results show that positional BS is a relatively fast process, stabilised in 10 minutes, with local variations strongly dependent on the variability of anatomical structures between different subjects. |
| 3839 | Computer 160
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Motion tracking using simultaneous MR and 4D ultrasound acquisition for image guided radiation therapy |
1GE Global Research, Niskayuna, NY, United States, 2Medical Physics, University of Wisconsin, Madison, WI, United States, 3Radiology, University of Wisconsin, Madison, WI, United States, 4Human Oncology, University of Wisconsin, Madison, WI, United States |
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An MR-compatible 4D ultrasound probe allows hands-free, simultaneous MR and ultrasound image acquisition. This new imaging capability provides a path for tracking tumor target motion during radiation therapy, as an alternative to an integrated MR-LINAC system. To facilitate this, the ability to track the motion of fiducial markers as an indication of respiratory state is essential. In our approach, as the MR images are acquired outside of the radiation therapy procedure, motion tracking of endogenous ultrasound fiducials is proposed to determine respiratory states. |
| 3840 | Computer 161
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Catheter-based Arterial Input Function for Quantitative Perfusion Measurements with Intra-arterial Injection |
1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany |
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MR-guided vascular interventions allow for direct injection of contrast agent (CA) through a catheter, which can be used for perfusion measurements of the target tissue, for example, the myocardium in MR-guided coronary catheterizations. For a quantitative perfusion measurement an arterial input function (AIF) is required that describes the CA concentration-time curve in the artery. In this work we show initial results of two methods to determine the AIF during an intervention and demonstrate the feasibility of measuring the AIF in intra-arterial CA injections based on the signal of an active guiding catheter. |
| 3841 | Computer 162
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Modeling of Active Shimming of Metallic Needles for Interventional MRI |
1Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, United States |
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Needle artifacts caused by large magnetic susceptibility differences between metallic needles and stylets and the surrounding tissue are a persistent problem in interventional MRI. In this abstract, we present the concept, design and modeling results of a active shim system for needles inspired from degaussing coils used in naval vessels. Field disturbance induced by a Titanium needle at 3 Tesla is modeled and an active orthogonal shim coil insert design is presented to demonstrate shimming of the field variation around the needle. This work lays the foundation for designing full generalized active shim systems for Interventional MRI probes. |
| 3842 | Computer 163
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A Machine Learning Based Biomechanical Model for Real-time MR-guided Neuro-intervention |
1Biomedeical Engineering, Shanghai Jiaotong University, Shanghai, China, 2KTH Royal Institute of Technology, Stockholm, Sweden, 3Functional Neurosurgery, Shanghai Jiaotong University, Shanghai, China, 4Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States |
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Magnetic resonance (MR) guided neuro interventions could be combined with robotic assisted manipulation to achieve optimal performance. Patient specific model constructed from MR images of the brain could have the best biophysical fidelity but suffers from high computational cost. For real-time applications, we proposed to construct an Artificial Neural Network (ANN) based on the training from computational outputs of Finite element Analysis (FEA). Results demonstrate the ability to achieve accurate predictions given by a mean square error (MSE) of 0.0338 mm2 within 10ms. |
| 3843 | Computer 164
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MRI artifact simulation for clinically relevant MRI sequences for guidance of prostate HDR brachytherapy |
1Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 2Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands |
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Object localization by MRI artifact simulation and template matching is valuable for MRI-guided HDR brachytherapy. Simulations of the artifacts induced by an HDR brachytherapy source and titanium needle were implemented for four types of MRI sequences: spoiled gradient echo, spin echo, bSSFP and bSSFP-SPAIR. The simulated artifacts were compared to MR images acquired in a phantom study and applied for object localization. High correspondences between the simulations and MR images were found as well as only slight variations between the obtained object positions for all applied sequences. This enables object localization for clinically relevant MRI sequences which allow anatomy visualization. |
| 3844 | Computer 165
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Real-time Automatic Tip Tracking of Gadolinium-filled Balloon Wedge Catheter during MR-guided Cardiac Catheterization |
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom |
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MRI-guided cardiac catheterisation procedures are commonly performed using balloon wedge catheters which are currently manually tracked. Furthermore, these procedures require frequent manual adjustment of the slice positioning during catheter navigation. In this study, we sought to develop a novel acquisition and reconstruction framework that enables automatic tracking of a gadolinium-filled balloon wedge catheter using (a) real-time partial saturation with increased spatial coverage, (b) automatic image-based estimation of the catheter balloon position, and (c) real-time slice tracking. The proposed framework is demonstrated during an MRI-guided cardiac catheterisation experiment in a 3D printed heart phantom. |
| 3845 | Computer 166
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Ferromagnetic markers for interventional MRI devices at 0.55T |
1NIH, Bethesda, MD, United States, 2Cook Medical, Bloomington, IN, United States |
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Interventional cardiac MRI has been hampered for decades by the lack of safe and visible devices. Guidewires (long, elongated metals) risk RF-induced heating under MR, and often incorporate ferromagnetic markers (e.g.stainless steel) that can be used for image guidance. We propose MR-guided interventions at 0.55T to avoid RF-induced heating. Here we show that at 0.55T, ferromagnetic markers maintain visibility and create identical artifacts to those observed at 1.5T. We show that using a high-performance low field MRI system may enable progress in interventional MRI due to improved device safety with retained image quality. |
| 3846 | Computer 167
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Clinical MRI-guided right heart catheterization with standard metallic devices using a high performance 0.55T system |
1Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States |
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MRI-guidance of invasive cardiovascular procedures has been limited by the unavailability of safe devices. Most cardiovascular procedures require long conductive devices (eg. guidewires and catheters) that are susceptible to RF-induced heating. Because heating is related quadratically to field strength, we propose to reduce the MRI field strength to 0.55T. Using a custom high-performance 0.55T MRI system, we performed MRI-guided catheterizations on patients with commercial metallic guidewires using standard high flip angle bSSSP real-time imaging to produce good image quality and contrast without RF-induced heating. Low field MRI combined with high-performance hardware will be fundamentally enabling for MRI guidance of invasive procedures. |
| 3847 | Computer 168
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Proof-of-concept of retrospective gating for interventional cardiac MRI using catheter microcoils readings. |
1IHU LIRYC, PESSAC, France, 2Siemens Healthcare, Saint-Denis, France, 3Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France, 4INSERM U1045, Bordeaux, France |
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In the context of radiofrequency ablation of cardiac arrhythmia, a catheter is inserted into the heart for contact electrophysiology recording and/or ablating the arrhythmogenic substrate. In this context, we propose to exploit MR-compatible microcoils located near the catheter tip to estimate the local motion of the heart. For this, a tracking module was interleaved with segments of a radial acquisition in a FLASH sequence. k-space segments were sorted retrospectively according to tracking readings before image reconstruction. Using this approach, artifact free images of a pig in vivo could be reconstructed. |
| 3848 | Computer 169
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3D CNN-based synthetic CT generation for head and neck radiotherapy using a clinically used turbo spin-echo T2-weighted sequence |
1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2Radiotherapy Department, University Medical Center Utrecht, Utrecht, Netherlands, 3MRIguidance, Utrecht, Netherlands |
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Deep learning-based synthetic CT (sCT) generation models are often based on T1-weighted gradient echo sequences. However, these sequences are generally not used for tumor/organs-at-risk delineation. In this study, we trained a U-Net type neural network using T2-weighted turbo spin-echo images from the clinical radiotherapy treatment planning protocol originally used for tumor/organs-at-risk contouring. The use of clinical images preserves scan times and facilitates soft tissue delineation on the source images of the sCTs, avoiding registrations. We showed that sCTs generated by the trained model provide accurate dosimetric results while limiting CT-induced streaking dental artefacts. |
| 3849 | Computer 170
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MINIMA – Minimally invasive, image guided ablation using MRI |
1Centre for Advanced Biomedical Imaging, UCL, London, United Kingdom, 2Davy-Faraday Research laboratories, UCL, London, United Kingdom |
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Minimally invasive, focal therapies aim to deliver more effective treatment to the patient while reducing off target effects. As such, we have developed MINIMA, a minimally invasive, image-guided ablation MRI technique, whereby a magnetic thermoseed can be manoeuvred through tissue, localised with real time imaging and then heated to cause cell death. We demonstrate submillimetre precision of movement through ex vivo brain tissue and that the seed can be heated via application of radiowaves to cause well defined regions of cell death. These results show that MINIMA is a promising new technique that could help transform MRI into a brand new theranostic device. |
| 3850 | Computer 171
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Imaging latency of Golden Angle 2D MRI using real-time GPU-accelerated image reconstruction for MR-guided radiotherapy |
1Radiotherapy, UMC Utrecht, Utrecht, Netherlands |
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For tumor tracking in MRI-guided radiotherapy it is important to minimize the latency between the moment of anatomic change and its appearance on the MR image. By using a 2D golden angle sampling trajectory in combination with a sliding window reconstruction, the latency can be decoupled from the frame rate, yielding frame rates of up to one repetition time. We implemented a real-time GPU-accelerated reconstruction pipeline where k-space data is directly streamed to a reconstruction server during acquisition. Using this we investigated the influence of the sliding window width on the latency, reconstruction time, frame rate and image quality. |
| 3851 | Computer 172
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Feasibility and Demonstration of Controlled, Comprehensive Delivery of Clot-busting Drugs for MR Image-Guided Intracerebral Clot Evacuation |
1Medical Physics, University of Wisconsin, Madison, WI, United States, 2Animal Sciences, University of Wisconsin, Madison, WI, United States, 3Radiology, University of Wisconsin, Madison, WI, United States, 4Neurosurgery, University of Wisconsin, Madison, WI, United States |
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A recent NIH Trial has shown success in minimizing the effects of intracerebral hemorrhage through insertion of a minimally invasive catheter into the clot through a craniotomy. The catheter then injects 1 ml of clot-busting drugs followed by an 8 hour period of draining the lysed blood. The conservative procedure is repeated for 3-5 days as only very small dosages can be administered due to CT’s inability to directly monitor the drug’s safe distribution. We demonstrate how pressurized infusions can create broader treatments that lyse the clot rapidly while MRI visualizes the drug distributions to maintain safety. |
| 3852 | Computer 173
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EVALUATION OF FPI BASED CUSTOM FORCE SENSOR DESIGN FOR BIOPSY NEEDLES |
1Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey |
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In this work, an MRI compatible Fabry-Pérot Interferometry (FPI) based force sensor is designed and fabricated using novel methods, and integrated into an 18-gauge nitinol biopsy needle. The resolution of the FPI based sensor is increased by coating optical fibers with magnesium and titanium thin film. The force sensing needle is tested by in vitro experiments using a prostate phantom and in vivo animal experiments under MRI. |
| 3853 | Computer 174
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A Body-Mounted Robot with Integrated Single Loop Coil for MR-Guided Arthrography |
1Children's Hospital / SZI, Washington DC, DC, United States, 2Imaging Research Center, Cincinnati Children's Hospital, Cincinnati, OH, United States |
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The purpose of this project is to streamline the workflow for robotic-assisted MR-guided arthrography by integrating a single loop coil in the base / mounting adapter of the robot. This coil provides sufficient spatial coverage and sensitivity to localize anatomic points of interest and registration fiducials embedded in the robot. Integration of the coil with the robot places the imaging coil as close as possible to the patient and reduces the number of devices that need to be managed during an interventional procedure. Quantitative results for SNR and an end-to-end targeting study using a phantom are reported in the abstract. |
| 3854 | Computer 175
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Automatic pelvic bone registration of low-field MRI to pre-operative 3T-MRA for vascular interventions |
1Magnetic Detection & Imaging, University of Twente, Enschede, Netherlands, 2Vascular surgery, Medisch Spectrum Twente, Enschede, Netherlands, 3Robotics and Mechatronics, University of Twente, Enschede, Netherlands |
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Intra-operative low-field magnetic resonance imaging (LF-MRI) is characterized by poor spatial resolution limiting its use in endovascular catheter tracking with fluoroscopy. Fusion of LF-MRI with 3T-MRI may overcome this issue. To fuse both volumes, we automatically segmented a pelvis from an LF-MRI scan, based on cortical bone detection with Laplacian edge detection. A similarity of 66% was reached between automatic and manual segmentation. Subsequently, the segmented volume was automatically registered to a 3T-MRA. Compared to a Procrustes based manual registration, the automatic registration resulted in a root-mean-square error of 3 mm. |
| 3855 | Computer 1
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Brain connectivity assessed by mechanical covariance |
1Radiology, Mayo Clinic, Rochester, MN, United States, 2School of Medical Imaging, Xuzhou Medical University, Xuzhou, China, 3Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States, 4Neurology, Mayo Clinic, Rochester, MN, United States |
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| 3856 | Computer 2
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Functional Connectome Fingerprinting using Recurrent Neural Networks Does Not Depend on the Temporal Structure of the Data |
1UCSD Center for Functional MRI, La Jolla, CA, United States, 2Beihang University, Beijing, China, 3Canyon Crest Academy, San Diego, CA, United States |
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Functional connectome fingerprinting can identify individuals with high accuracy with long duration scans (> 6 min) but the performance significantly degrades with shorter (72s) duration scans. It has been argued that Recurrent Neural Networks (RNN) can achieve high identification performance with short duration data by taking advantage of temporal information in the fMRI signals. We test this claim by permuting the temporal ordering of the data. We show that the RNN can achieve high accuracy for short duration data even when the temporal structure is destroyed, suggesting that the RNN performance depends primarily on the spatial correlation of the data. |
| 3857 | Computer 3
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Arterial spin labeling pre-processing strategies for functional connectivity analysis |
1Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, 2Radiology, Vanderbilt University Medical Center, Nashville, TN, United States |
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Arterial spin labeling-based functional connectivity (ASL-FC) is an emerging method to identify synchronous brain networks from perfusion fluctuations. ASL-FC may compensate for some susceptibility-induced limitations in blood-oxygenation-level-dependent (BOLD)-FC, however ASL-FC processing strategies are only beginning to be investigated. We evaluate optimized ASL-FC pre-processing for network detection, testing the effects of six pre-processing strategies by comparing spatial and temporal features with BOLD-FC in major brain networks. Spatial smoothing, surround subtraction, and global signal regression are necessary to increase ASL-FC sensitivity. ASL-FC also allows for low frequencies to be interrogated, which contain high power but are inaccessible to common BOLD-FC analyses. |
| 3858 | Computer 4
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Automatic Identification of ICA Components using A Generative Adversarial Network |
1Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States, 2Laboratory of Functional and Molecular Imaging, NINDS, Bethesda, MD, United States, 3Radiology and Imaging Sciences, NIH, Bethesda, MD, United States |
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Manual classification of the components derived from ICA analysis of rsfMRI data as particular functional brain resting state networks (RSNs) can be labor intensive and requires expertise; hence, a fully automatic algorithm that can reliably classify these RSNs is desirable. In this paper, we introduce a generative adversarial network (GAN) based method for performing this task. The proposed method achieves over 93% classification accuracy and out-performs the traditional convolutional neural network (CNN) and template matching methods. |
| 3859 | Computer 5
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Simultaneous measurement of functional connectivity and cerebrovascular reactivity (CVR): feasibility of vasculature-normalized fcMRI |
1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Neuroimaging Research Branch, National Institute on Drug Abuse, Baltimore, MD, United States, 4Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, United States, 5Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan |
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Although widely used in fMRI to assess functional connectivity (FC), the blood-oxygenation-level-dependent (BOLD) signal is not merely a representation of neural activity, but also inherently modulated by vascular physiology. It is therefore desirable to conduct FC mapping with consideration of vascular properties, ideally in the same scan. The present work demonstrated that FC and cerebrovascular reactivity (CVR) could be obtained from BOLD images collected during a single CVR scan. Moreover, the FC indices from gas-inhalation data showed a significant correlation with CVR, suggesting the potential of using CVR as a covariate or normalization factor in interpreting FC results. |
| 3860 | Computer 6
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Multi-Slice LINE-scanning (MS-LINE) method to characterize the laminar specificity and variability in both evoked and resting-state fMRI |
1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Graduate Training Centre of Neuroscience, Tuebingen, Germany, 3Department of Biomedical Engineering, NIJT, Newark, NJ, United States, 4MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States |
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Ultra-high field magnetic field strengths open new possibility for studying the neuronal input/output circuitry of the cortex and functional connectivity across the cortical layers. However, the spatiotemporal characteristics of laminar-specific fMRI signal remains to be better characterized in both task-related and resting state condition. Here, we present Multi-Slice FLASH based LINE-scanning (MS-LINE) methods, showing the multi-slice laminar-specific fMRI variability at different cortical regions of anesthetized rats. The results identify the distinct neurovascular coupling laminar patterns corresponding to different state of brain activity. |
| 3861 | Computer 7
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Classification of sleep stages from fMRI dynamic functional connectivity using deep learning |
1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico - Universidade de Lisboa, Lisbon, Portugal, 2ISR-Lisboa/LARSyS and Department of Electrical Engineering, Instituto Superior Técnico - Universidade de Lisboa, Lisbon, Portugal, 3Department of Neurophysiology, Centro Hospitalar Psiquiátrico de Lisboa, Lisbon, Portugal |
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Sleep stage classifiers monitoring the wakefulness level of resting-state fMRI recordings have been proposed by several studies; however, the application of deep learning methods remains largely unexplored. We investigated the performance of Convolutional Neural Networks (CNNs) in the classification of sleep stages using fMRI-derived dynamic Functional Connectivity (dFC) features and simultaneous EEG-based labels. All tested architectures exhibited accuracies above 80%, with the best performance achieved using a shallow network. The learned filter weights were coherent with known stage-specific patterns of thalamo-cortical dFC. CNNs yielded comparable classification accuracy to Support Vector Machines (SVMs), without the need for exhaustive hyperparameter tuning. |
| 3862 | Computer 8
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Identifying confounds in human brain functional connectomes: physiological and cognitive contributions |
1Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia, 2Monash Biomedical Imaging, Monash University, Melbourne, Australia, 3Centre of Excellence for Integrative Brain Function, Australian Research Council, Melbourne, Australia |
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Inter-subject analysis of brain function using fMRI is hampered by physiological factors and the neurovascular origin of the semi-quantitative blood oxygenation level dependent signal. A common technique to address these issues is to compute the individual subject fMRI signal correlations between brain regions and compare the functional connectomes across subject groups. In this work, we examined the effect of physiological factors that can contaminate functional connectomes in a large cohort of healthy elderly people. To quantify the impact of the physiological variance we computed the physiological connectome and modelled its impact on the relationship between the functional connectome and cognitive performance. |
| 3863 | Computer 9
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Altered Effective Connectivity Anchored in the Posterior Cingulate Cortex and the Medial Prefrontal Cortex in Cognitively Intact Elderly APOE ε4 Carriers: A Preliminary Study |
1The 2nd Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China, 2GE Healthcare Shanghai, Shanghai, China |
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The APOE ε4 allele is the most reliable genetic risk factor for developing sporadic AD. Based on Granger causality analysis (GCA), we analyzed the APOE ε4-related effects on whole-brain directional connectivity in healthy elderly populations, by setting connected node located in anterior and posterior default mode network (DMN). We found that APOE ε4 carriers had reduced effective connectivity (EC) from the PCC to the anterior and posterior DMN subsystems; additionally, the carriers had increased EC from the parietal cortex to the anterior DMN subsystem. Second, the correlation analyses indicated the decreased EC in the carriers might result from neurofibrillary changes. |
| 3864 | Computer 10
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Olfaction connectivity in Patients with Parkinson’s disease: A comparative fMRI study. |
1NMR & MRI Facilty, All India Institute of Medical Sciences, New Delhi, India, 2Neurology, All India Institute of Medical Sciences, New Delhi, India, 3All India Institute of Medical Sciences, New Delhi, India, 4Biostatistics, All India Institute of Medical Sciences, New Delhi, India |
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Olfactory loss is one of the most common non-motor symptoms in Patients with Parkinson’s disease. ROI based functional connectivity analysis was performed on 10 healthy subjects (HC, 6M/4F, mean age=57±4.5 years) and 10 subjects with Parkinson’s disease (9M/1F, mean age=57.7±5.6 years) with olfaction fMRI (floral smell). Altered olfaction linked functional connectivity was present for amygdala, insula and cingulate gyrus in PD. Functional connectivity for olfactory cognition (hippocampus/orbitofrontal) was found intact in both the groups. Primary olfactory structures are more affected compared to the upstream structures, leading to the observed olfactory impairment. |
| 3865 | Computer 11
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Sparse Dictionary Learning and Deep Convolutional Auto-encoders as Alternative Methods to ICA for Resting-State Network Detection |
1University of Georgia, Athens, GA, United States, 2Physics and Astronomy, University of Georgia, Athens, GA, United States, 3Bio-Imaging Research Center, University of Georgia, Athens, GA, United States |
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Though Independent Component Analysis (ICA) is a commonly-used method for resting state network (RSN) detection from resting-state fMRI (rsfMRI) data, it is limited by its assumption of spatial independence requiring that detected networks be non-overlapping. This study investigates the use of Sparse Dictionary Learning (SDL) and Deep Convolutional Auto-Encoders (DCAE) as alternative methods for RSN detection using Human Connectome Project rsfMRI data. Using the Smith10 RSN Atlas as a ground truth, Pearson spatial correlation and spatial overlap scores were used as metrics of performance, and it was found that SDL and DCAE outperform ICA in detecting RSNs in single session analyses. |
| 3866 | Computer 12
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Global signal measures are significantly related to functional connectivity variations across scans both before and after global signal regression |
1University of California, San Diego, La Jolla, CA, United States |
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Global signal regression (GSR) is widely employed to reduce the influence of nuisance factors in functional connectivity (FC) estimates. Here, we investigate the GS contributions to the variability of FC estimates across different scans. We show that correlation-based FC estimates are significantly related to the GS norms across scans. We further show that even after GSR there is still a significant relation between the GS norms and FC estimates, indicating that inter-scan FC variations can largely reflect GS effects both before and after GSR. |
| 3867 | Computer 13
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A BRUTE FORCE APPROACH TO IMPROVE THE CLASSIFICATION ACCURACY IN RESTING STATE FMRI DATA |
1Computer Science, University of New Mexico, Albuquerque, NM, United States, 2The Mind Research Network, Albuquerque, NM, United States, 3Harvard Medical School, Boston, MA, United States |
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Currently, extensive research is ongoing to perform classification between healthy controls (HC) and patients by extracting features from resting state fMRI based dynamic connectivity states where these states are typically identified by applying different clustering algorithm. However, for classification purposes, the information captured by all dynamic states may not be significant. In this work, we propose a brute force (BF) approach where we consider a subset of these states to perform classification. Our results indicate that in most of the cases, there exists a subset of states which provides better accuracy instead of utilizing information from all of the states. |
| 3868 | Computer 14
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Resting-state functional connectivity estimates across scans are correlated with nuisance metrics both before and after nuisance regression |
1Zhejiang University, Hangzhou, China, 2University of California, San Diego, La Jolla, CA, United States |
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Nuisance regression is commonly used to reduce the influence of nuisance effects on functional connectivity (FC) estimates. Here we demonstrate that FC estimates across different scans are significantly correlated (prior to nuisance regression) with the norms of various nuisance signals including head motion regressors and signals from non-functional regions. We further show that nuisance regression does not necessarily eliminate the observed correlations between the FC estimates and nuisance norms. We demonstrate that the limited efficacy of nuisance regression is partly due to a theoretical bound that limits the difference in FC estimates obtained before and after regression. |
| 3869 | Computer 15
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Quantitative Assessment of Temporal Changes in fMRI and DTI Parameters in the Squirrel Monkey Spinal Cord after Injury |
1Radiology, Vanderbilt University, Nashville, TN, United States |
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Previous studies have reported changes in resting state functional connectivity between horns in spinal cord following injury. In this work we quantified changes in connectivity and diffusion parameters at identical spinal segments in squirrel monkey cervical spinal cords acquired in concurrent sessions to compare the temporal variations of functional and structural changes during recovery after spinal cord injury (SCI). The degree of axonal disruption and demyelination measured using fractional anisotropy and radial diffusivity at two stages of recovery were compared in various white matter tracts. |
| 3870 | Computer 16
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Simple Data Acquisition Choices can Adversely Affect Preprocessing Strategies in Resting State fMRI |
1Imaging Institute, Cleveland Clinic Foundation, Cleveland, OH, United States |
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Common resting state fRMI preprocessing steps are done in the Fourier domain, in particular temporal filtering. These can introduce temporal artifacts that can be exaggerated by using data time-series that are not power of 2 in length. We show that using non-power of 2 data can affect the shape of the temporal filter being applied and can increase unwanted correlations from aliased physiologic noise for example and introduce increased autocorrelations in the data. |
| 3871 | Computer 17
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Sequential Monte Carlo for studying effective connectivity in fMRI |
1Imago7 Research Foundation, Pisa, Italy, 2IRCCS Stella Maris, Pisa, Italy, 3ISTI-CNR, Pisa, Italy, 4University of Pisa, Pisa, Italy |
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The signal fluctuations in Functional Magnetic Resonance Imaging (fMRI) have been proved suitable for investigating brain connectivity. Sequential Monte Carlo methods (“particle filters”) aim at estimating internal states in dynamic systems when only partial and noisy observations are available. Differently from the majority of techniques commonly used for investigating brain connectivity, which assume stationarity, particle filters are designed for stochastic time-varying systems. We present a particle filtering algorithm tailored to fMRI data, whose purpose is to help assessing the presence of causal influences that certain brain areas may exert over others. The algorithm has been validated on a simulated network and applied to real fMRI data. |
| 3872 | Computer 18
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A combination of dynamic community structure and machine learning methods in tracking Alzheimer's disease-related functional reorganization |
1Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China |
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Brain networks have a modular structure in function and this modular organization changes dynamically with time. However, the available brain network modularization methods are limited to detect functional modules for static brain network.So the aim of this sttudy is to propose a consensus algorithm to evaluate the modularization of functional brain network of healthy individuals and patients with Alzheimer's disease.The measures for the modularization of functional brain networks included normalized mutual information (NMI), average participation coefficient and classification accuracy.To evaluate the results from the consensus algorithm, machine learning based classification was performed on a new AD data sets. |
| 3873 | Computer 19
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Slice Timing Effects on Spectral Dynamic Causal Modeling |
1University of Wisconsin - Madison, Madison, WI, United States, 2Medical College of Wisconsin, Milwaukee, WI, United States |
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Functional MRI may not be slice time corrected when time differences are less than one second. However, these differences may be important for causal neuronal relationships. We investigated slice timing correction in spectral dynamic causal modeling using multiband resting-state data with TR = 802 ms from controls and temporal lobe epilepsy patients. Differences investigated were numeric value, parameter interpretation, and group level models. No significant difference in the first two were found. Group level modeling differences were found. Thus, slice timing correction appears necessary when applying spectral dynamic causal modeling even with slice timing differences of less than one second. |
| 3874 | Computer 20
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Seed-based test-retest reliability of resting state function magnetic resonance imaging at 3T and 7T. |
1Imaging Sciences, Cleveland Clinic Foundation, Cleveland, OH, United States |
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A novel hybrid seed-based approach to assess the test-retest reliability of ICNs is introduced that uses an exhaustive but systematic, ROI-limited search for seed pairs with maximal correlation. We examine the reproducibility of these seed pairs and their relation to four well-known ICNs. We then use this approach to assess test-retest reliability between subjects scanned at 3T and 7T field strengths. |
| 3875 | Computer 21
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The functional network construction by using Pearson’s correlation, mutual information and convergent cross mapping |
1Clinical Science, Philips Healthcare, Beijing, China, 2Capital Medical University, Beijing, China |
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To compare and evaluate the functional networks constructed by using Pearson’s correlation, mutual information and convergent cross mapping. |
| 3876 | Computer 22
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Comparison of 3T and 7T PCC seed based spontaneous co-activation analysis |
1Radiology, Cleveland Clinic, Cleveland, OH, United States, 2Biomedical Engineering, Pennsylvania State University, University Park, PA, United States, 3Institute for Cyber Science, Pennsylvania State University, University Park, PA, United States |
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Dynamic functional connectivity techniques are increasingly being used investigate changes in neuronal network during resting state fMRI scanning. The spontaneous co-activation (CAP) approach has been proposed to reduce the dimensionality and shows the potential to characterize dynamic brain network in various ways. This study presents the first 7T CAP analysis, compared CAP analyses at 7T to 3T. |
| 3877 | Computer 23
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Functional Domain Connectivity Strength in Schizophrenia |
1The Mind Research Network, Albuquerque, NM, United States |
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Functional network connectivity (FNC) has been successfully used to detect dysfunctions on the brain of schizophrenia patients. However, this work proposes the idea that effects can be observed when studying functional domains (groups of functionally related brain areas). A set of previously unobserved dysfunctions were detected by studying the domain connectivity strength. Domain connectivity is an important framework for future research of functional connectivity. |
| 3878 | Computer 24
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Regional Brain Resting-State Neural Activity in Patients with Single Ventricle Heart Disease |
1Departments of Anesthesiology, University of California Los Angeles, Los Angeles, CA, United States, 2School of nursing, University of California Los Angeles, Los Angeles, CA, United States, 3Division of Pediatric Cardiology, University of California Los Angeles, Los Angeles, CA, United States, 4Division of Pediatric Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, United States, 5University of California Los Angeles, Los Angeles, CA, United States |
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Patients with single ventricle heart disease (SVHD) commonly show brain structural injuries in autonomic, mood, and cognition regulatory areas. However, whether SVHD subjects have functional impairments in these sites is unknown. We examined regional neural activity changes in SVHD patients, and found reduced regional homogeneity (ReHo) in posterior cingulate, medial prefrontal cortex, inferior parietal lobule, and left insula, and increased ReHo in bilateral middle occipital gyrus, cerebellar cortices, and left superior temporal gyrus over control subjects. These functional changes might be associated with impairments in autonomic, mood, and cognitive functions found in the condition. |
| 3880 | Computer 26
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Identifying motif patterns of directed brain functional networks in schizophrenia |
1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Southern Medical University, Guangzhou, China |
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In this study, we aimed to investigate the motif patterns of the directed brain functional networks in schizophrenia. We employed the convergent cross mapping approach to measure the directed connections, and calculated the frequency spectrum and the statistical significance of 13 three-node motif classes. Our results showed that the count of all motif classes was significantly reduced, the significance of chain-like motifs was decreased and the significance of loop-like motifs was increased at both whole brain and modular scales in schizophrenia. The motif analyses have potential to provide new insights of the abnormal information flow patterns in schizophrenia. |
| 3881 | Computer 27
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Changes in resting state networks in major depression following ketamine administration |
1ETPB, NIH, Bethesda, MD, United States |
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Recently, it has been shown that individual classification of subjects across scans is possible using correlation matrices derived from their resting state data. In the current study, a cohort of patient with major depression and healthy controls each had five resting state fMRI scans over the course of a double blind randomized placebo controlled cross-over ketamine infusion study We apply this classification scheme to our data to see if we can link individual functional connectivity profiles to behavioral improvements after ketamine. |
| 3882 | Computer 28
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Weaker Intra- and Inter-nodal Connectivity of Resting State Networks in Drug-naive Attention-Deficit/Hyperactivity Disorder |
1Department of Radiology, Huaxi Magnetic Resonance Research Centre (HMRRC), Chengdu, China, 2Department of Psychiatry, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China |
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We used group-level independent component analysis (ICA) to investigate functional network connectivity in drug-naïve ADHD children. We extracted eight resting state networks and found that lower intranodal and internodal functional connectivity among executive control, precuneus and default mode networks in ADHD children compared to controls, especially located in prefrontal and parietal regions. This finding may provide new insights into functional connectivity alterations in ADHD children and promote the exploration of functional network connectivity in future researches. |
| 3883 | Computer 29
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Hemisphere-specificity between global synchronization of spontaneous brain activity and movement function in Hippocampus of Parkinson’s disease patients: a resting-state fMRI study |
1Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Deep Bay Innovation Co., Ltd., Shenzhen, China, 3Department of Neurology, Guangzhou First People’s Hospital, Guangzhou, China, 4Department of Radiology, Guangzhou First People’s Hospital, Guangzhou, China |
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This study enrolled age-match of 36 people with PD and 35 normal controls (NC) in resting-state functional MRI. Altered global signal synchronizations in PD were explored, and correlations between global synchronizations and clinical assessments (cognitive and movement functions) were investigated. Alterations of global synchronizations were observed in left postcentral gyrus (PostC), left supramarginal gyrus and right opercular-inferior frontal gyrus in people with PD. The correlation results imply postcentral gyrus and hippocampus as critical brain regions associated with both cognitive performances and movement functions in PD. |
| 3884 | Computer 30
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Disrupted Cerebellar Connectivity with the Central Executive Network and the Default-mode Network in unmedicated Bipolar II Disorder |
1Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou, China, 2Institute of Molecular and Functional Imaging, Jinan University, Guangzhou, China, 3Department of Psychiatry, First Affiliated Hospital of Jinan University, Guangzhou, China, 4Department of Radiology, Six Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, 5Department of Radiology, Gansu Provincial Hospital, Gansu, China, 6GE Healthcare, MR Research China, Beijing, China |
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The present study aims to investigate the FC between the cerebellum and cerebrum, particularly the central executive network (CEN) and the default-mode network (DMN) in BD II. Seed-based connectivity analyses were performed in 94 unmedicated BD II depression and 100 healthy controls (HCs). Patients with BD II depression showed disrupted FC between the cerebellum and the CEN (mainly in the left dlPFC and ACC) and DMN (mainly in the left mPFC and temporal lobe), suggesting the significant role of the cerebellum-CEN and -DMN connectivity in the pathogenesis of BD. |
| 3885 | Computer 31
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Investigating the feasibility of predicting somatosensory function of stroke patients from resting-state functional connectivity |
1Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia, 2Florey Department of Neuroscience and Mental Health, The University of Melbourne, Heidelberg, Australia, 3College of Science, Health and Engineering, La Trobe University, Melbourne, Australia |
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Accumulating evidence from human imaging data supports association between connectivity and outcome after stroke. However, whole-brain functional-connectivity (FC) involves high-dimensional data, which essentially calls for multivariate analysis. Regardless, univariate analysis has been dominantly employed for such studies. More insights into stroke recovery by employing machine learning techniques can be offered due to their multivariate capabilities. In this study, we investigated if residual sensory function (Tactile discrimination threshold, TDT score) of stroke patients can be predicted from resting-state FC. Our results show that TDT scores can be predicted more accurately by combining both low-order and high-order FC than low-order functional connectivity alone. |
| 3886 | Computer 32
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Altered functional connectivity manifested by disrupted network modularity in chronic stroke patients |
1Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia, 2Florey Department of Neuroscience and Mental Health, The University of Melbourne, Heidelberg, Australia, 3College of Science, Health and Engineering, La Trobe University, Melbourne, Australia |
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Recent studies have shown that brain connectivity analyses offer valuable information in quantifying network alterations after stroke , which could further enhance our understanding the mechanism of stroke recovery. Given the issue of heterogeneous lesion locations, a recent approach, GMGLASS, is employed to alleviate this issue due to its capability in conducting group comparison studies despite large inter-subject variability. Furthermore, while previous studies have shown that homotopic connections are disrupted due to stroke lesions, how lesion laterality disrupts brain networks, especially at modular level, is not known yet. In this study, we quantified the whole-brain functional connectivity differences using network analysis methods; furthermore, we investigated disruption of homotopic connections at network modular level. |
| 3887 | Computer 33
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Brain mechanisms underlying Gulf War Illness revealed by connectomics signatures of the disease |
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, 2University of Houston-Clear Lake, Houston, TX, United States, 3Department of Neurology, Emory University, Atlanta, GA, United States, 4Atlanta VA Medical Center, Decatur, GA, United States, 5Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States |
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Around 200,000 veterans (up to 32% of those deployed) of the 1991 Gulf War (GW) suffer from GW illness (GWI), which is characterized by multiple deficits in cognitive, emotion, sensory and nociception domains. In this study we examined 60 GWI patients and 30 age-matched controls with resting state fMRI (rsFMRI) in order to map impairments in brain function networks in GWI with group independent components analysis. GWI veterans exhibited impaired/abnormally increased FC between different brain function networks, revealing brain mechanisms underlying neurological impairments in GWI. |
| 3888 | Computer 34
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Dynamic Functional Connectivity Distinguishes Concussed Youth Based on Symptomology |
1University of Calgary, Calgary, AB, Canada |
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Concussion in youth is a growing health issue, and accurate diagnostic, progostic and assessment tools are lacking. In this study, we used a toolbox recently developed by our group (HOCo) to investigate dynamic functional connectivity in fMRI datasets obtained from groups of concussed and orthopedic injured (OI) control subjects. We estimated the proportion of the time that regions of the brain are significantly connected within specific networks. We found that concussed youth with somatic symptoms exhibited more stable connections of the motor and auditory networks, relative to OI subjects and concussed youth with cognitive symptoms. |
| 3889 | Computer 35
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Olfactory Network Functional Connectivity with the Hippocampus in Alzheimer’s Disease |
1Radiology, Penn State University, Hershey, PA, United States, 2Neurology, Penn State University, Hershey, PA, United States |
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The rhinencephalic brain regions are specifically vulnerable to AD pathology. This suggests that olfactory assessment may be able to serve as a measure of AD progression. In this research, we investigated the functional connectivity (FC) between the olfactory network (ON) and the hippocampus as a sensitive marker to detect progressive AD pathophysiology. The results show that the ON FC is able to differentiate between early mild cognitive impairment (MCI) and late MCI subjects. As such, ON FC may provide critical insights into relationships between olfactory, memory and, other cognitive deficits in AD. |
| 3890 | Computer 36
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Fractional amplitude of low frequency fluctuation associated with chess expertise: possible role of insular cortex |
1101 Nicolls Road, Stony Brook Medicine, Stony Brook, NY, United States, 2Biomedical engineering, Stony Brook University, Stony Brook, NY, United States, 3Radiology, Stony Brook Medicine, Stony Brook, NY, United States |
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While various expertise domains have been studied extensively, the literature body provides only a few reports on chess expertise at rest. To fill the literature gap of resting-state study on chess expertise, we fALFF differences on a dataset consists of 29 chess experts and 29 novices and found a higher fALFF in the right |
| 3891 | Computer 37
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Aberrant Functional Connectivity and Network Topology in Parkinson’s Disease Patients with Mild Cognitive Impairment. |
1Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States, 2University of California, San Diego, San Diego, CA, United States, 3Stanford University, Stanford, CA, United States |
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Studies have shown that cognitive impairment is a frequent non-motor manifestation of Parkinson’s disease (PD), and can already be detected in 15 to 40% of newly-diagnosed PD patients with up to 80% of patients eventually developing dementia. Our results show decreased functional connectivity between regions known to be implicated in high level cognitive functioning in Parkinson’s disease patients with mild cognitive impairment (PD-MCI) , when compared to the cognitively normal PD patients(PD-nMCI). Furthermore, we found altered network topology in PD-MCI compared to the PD-nMCI group that was differentially correlated with neuropsychological measures. |
| 3892 | Computer 38
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Baseline functional connectivity features of the neural network nodes can predict improvement after masking therapy in tinnitus patients |
1Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China |
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We proved our hypothesis that functional connectivity features of the brain nodes determined by DC have potential in predicting the response of masking therapy. |
| 3893 | Computer 39
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The effects of masking therapy in tinnitus patients are characterized by longitudinally altered local activity and functional connectivity |
1Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China |
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This study is the first to investigate the neural modulation mechanism of long term masking therapy in tinnitus patients by combined employing two analytic methods. |
| 3894 | Computer 40
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The effect of 2-month meditation on brain functional connectivity |
1Computer Science, State University of New York at Binghamton, Binghamton, NY, United States, 2Cornell University, Ithaca, NY, United States |
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The sustained effect of meditation on brain functional connectivity (FC) was evaluated longitudinally in ten college students. FC maps before and after meditation practice were compared and the changes of FC were correlated to practice time. We observed a significantly increased FC between the default mode network (DMN) and the dorsal attention network (DAN), and within DAN. The increased FC between DMN and DAN and within DAN was associated with increased practice time. The findings support fast shifting of attention after practicing meditation for two months and lay a foundation for its clinical transformation if confirmed in a larger study. |
| 3895 | Computer 41
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The association between functional brain network and functional outcome after acute ischemic stroke |
1The University of Hong Kong, Hong Kong, Hong Kong, 2Tung Wah Hospital, Hong Kong, Hong Kong, 3Philips Healthcare, HKSAR, China, Hong Kong, Hong Kong |
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The relation between the functional brain networks and the recovery of acute stroke patients have been investigated. The choice of frequency scale may have major impact on the results of functional connectivity and network analysis. In our study, we acquired resting state data from 11 patients with ischemic stroke and explored longitudinal changes in functional connectivity and brain network measures for various frequency. We also investigated the association between these longitudinal changes and brain functional recovery. |
| 3896 | Computer 42
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Increased Functional Connectivity of Insular Subregions Imporves Smoking Cessation Likelihood |
1Radiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China |
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Most smoking cessation attempts result in failure. Damage to the insular cortex disrupts smoking behavior in stroke patients. Neuroimaging studies have shown that chronic smokers had altered functional connectivity (FC) of insular subregions. Here, we further investigated the different FC changes of insular subregions between smokers who quitted successfully and those who relapsed after smoking cessation treatment. We found that smokers who quitted successfully had increased FC of anterior insula, while those who relapse had decreased FC of insular subregions. These novel findings suggest that increased connectivity of insular subregions could imporve likelihood of cessation. |
| 3897 | Computer 43
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Peculiarities of brain activation during dominant hand tactile perception in lateralized Parkinson disease |
1Anatomy and Physiology, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine |
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Parkinson's disease (PD) in mostly presented with asymmetrical motor symptoms. Disturbed sensorimotor integration and decrease of somatosensory cortex activation |
| 3898 | Computer 44
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Hippocampal atrophy and functional connectivity disruption in cirrhotic patients with minimal hepatic encephalopathy |
1Fujian Medical University Union Hospital, Fuzhou, China, 2Siemens Healthcare, Fuzhou, China |
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The hippocampus is a crucial pathological node for minimal hepatic encephalopathy (MHE) and it is associated with various cognitive impairments. We assessed hippocampal FC alterations in relation to regional volume and their associations with PHES results of cirrhotic patient and reached the following findings. (i) Hippocampal volume is significantly lower in MHE. (ii) A disruption of hippocampal connectivity to the default-mode network was observed in the MHE patients. (iii) The bilateral hippocampal FC strength (but not hippocampal volume) was positively correlated with the PHES results of the cirrhotic patients and aggravate with HE progression. Our findings revealed that both structural and functional abnormalities of the hippocampus are involved in the mechanism underlying cognitive deterioration with disease progression. |
| 3899 | Computer 45
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Altered the spinal trigeminal nucleus spontaneous brain activity and functional connectivity in female migraineurs without aura |
1East China Normal university, Shanghai, China, 2Shanghai Jiao Tong University School of Medicine, Shanghai, China |
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The purpose of this study was to investigate spontaneous neuron activity in spinal trigeminal nucleus (sTN) and its intrinsic functional connectivity (FC) with other key structures in migraineurs during resting-state fMRI scans. Thirty-five female migraine without aura (MWoA) during headache interictal phase and 35 age matched female HC were recruited. We found higher ALFF z-value of left sTN in female MWoA. We also found significantly weaker FC between the sTN and caudate putamen (CPu), and dorsolateral prefrontal cortex (DLPFC). Our results help us better understand the pathology of migraine. |
| 3900 | Computer 46
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Neural signatures underlying cognitive styles of field independence and field dependence: Evidence from resting-state fMRI |
1Institute of Nuclear Medicine and Allied Sciences (INMAS), Delhi, India, 2Defence Institute of Psychological Research (DIPR), Delhi, India |
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Cognitive style refers to the individual differences in the distinct preferences to think, learn, solve problems and to perceive and organize information about the surrounding space. Field dependence/ independence (FDI) is the most widely studied cognitive style and is measured by Group Embedded Figures Test (GEFT) that requires a participant to locate the simple shape embedded in a complex figure. FI subjects are less influenced by the information from the prevailing visual fields and perform better on GEFT as compared to the FD subjects. The cognitive style of an individual has been shown to be related to their cognitive functioning especially spatial memory performance, learning and retrieval of |
| 3901 | Computer 47
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Resting-state network distinguishes level of cerebral microbleed burden in patients with Immune Thrombocytopenia |
1Medicine, Imperial College London, London, United Kingdom, 2Haematology, Imperial College London, London, United Kingdom, 3Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom |
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In this study we evaluated resting state networks associated with cerebral microbleed presence in patients diagnosed with Immune Thrombocytopenia and identified a potential correlate of tiredness in the right superior parietal lobule. |
| 3902 | Computer 48
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Differences in resting state fMRI alterations between left and right early Bell’s palsy |
1Department of Radiology, China-Japan Friendship Hospital, Beijing, China, 2Graduate School of Peking Union Medical College, Beijing, China, 3GE Healthcare, China, Beijing, China |
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Bell’s palsy is defined as an idiopathic unilateral facial nerve palsy. Sixty-seven patients and 37 age- and sex-matched healthy controls were recruited in this study. Brain fractional amplitude of low-frequency fluctuation (fALFF) and and following functional connectivity (FC) were analyzed between left and right palsy groups. The results revealed brain reintegrating mechanisms differed between patients with left and right Bell’s palsy. |
| 3903 | Computer 49
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Effect of meditation on brain function activated by an attention task |
1Computer Science, Binghamton University, Binghamton, NY, United States, 2Cornell University, Ithaca, NY, United States |
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The effect of meditation on brain functional activation when engaged in an attention task was evaluated longitudinally using BOLD fMRI in nine young healthy subjects. Functional activation before and after meditation practice was compared and the change of functional activation was correlated with practice time. Following the meditation practice, response time to the attention task was significantly shorter; functional activation in the somatomotor network, frontal, basal ganglia, and insular regions was significantly reduced; more practice time was associated with less reduced activation. The findings suggest that meditation can improve brain efficiency but may have a complex neural mechanism. |
| 3904 | Computer 50
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Default mode networks connectivity characterization in young adults with sickle cell disease using 7T resting functional magnetic resonance imaging |
1Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, 2Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh, Pittsburgh, PA, United States, 3Pittsburgh Heart, Lung and Blood Vascular Medicine Institute, University of Pittsburgh school of medicine, Pittsburgh, PA, United States, 4Sickle Cell Center of Excellence, University of Pittsburgh school of medicine, Pittsburgh, PA, United States, 5Division of Hematology/Oncology, University of Pittsburgh school of medicine, Pittsburgh, PA, United States, 6Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 7Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States |
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In this study, we investigated altered resting state default mode network (DMN) connectivity using functional magnetic resonance imaging (rs-fMRI) at 7T in young adults(n=13) with sickle cell disease. The DMN of SCD of young adults had higher connectivity as compared to a healthy controls(n=9 ) gender, age, and racially matched group. |
| 3905 | Computer 51
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Evaluation of GLM fit dependency on the temporal sampling rate and the applied HRF model in BOLD fMRI |
1Brain Imaging Centre, Hungarian Academy of Sciences Research Centre for Natural Sciences, Budapest, Hungary, 2Laboratory for Social and Neural Systems Research, University of Zurich, Zurich, Switzerland |
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Modeling the haemodynamic response in fMRI is still subject of research. Recent developments in accelerated MRI enabled subsecond whole-brain fMRI. In this work we aim to examine the dependency of BOLD signal analysis on the temporal sampling rate and the applied HRF model by numerically undersampling a fast acquisition. Standard GLM fits with different HRF models were performed, followed by group-level statistical analyses and goodness-of-fit computations. The results indicate that variance across HRF models is increased in the undersampled datasets, while the low-pass-filtered undersampling also shows a possibility to enhance the statistical power on the group level. |
| 3906 | Computer 52
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Impact of small parcellation changes on global and local brain connectivity metrics: a study of resting state fMRI |
1Medical Physics Department, IRCCS Bambino Gesù Children’s Hospital, Rome, Italy, 2Imaging Department, IRCCS Bambino Gesù Children’s Hospital, Rome, Italy, 3NESMOS, Department of Neuroradiology, S. Andrea Hospital, Sapienza University, Rome, Italy |
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This work studied the impact of small parcellation changes on functional brain connectivity metrics. The study made use of Rs-fMRI dataset formed of 73 healthy controls and 73 schizophrenic patients. Brain parcellation was performed with standard atlasDKT40. Starting from this parcellation, fifty new parcellations were created by randomly modifying it. Weighted and unweighted adjacency matrices were constructed. 38 local and global network measures were derived. Brain connectivity measure variation factor was computed for each analysed measure. This study identified measures that are more robust with respect to spatial error in parcellation. |
| 3907 | Computer 53
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Automatic seed selection for resting state fMRI data analysis by using machine learning |
1Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, United States |
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To facilitate seed-based resting state fMRI (rs-fMRI) data analysis, we have been developing a method to automatically compute the seed location by using anatomical and rs-fMRI data. In the method, self-organizing map (SOM) is used to cluster voxels within searching ROI and then the seed locations are derived from the voxel clusters. The methods were tested on ten subjects to find seed in the motor cortex. The computed seeds successfully matched unilateral finger tapping fMRI maps in eight out of ten subjects. |
| 3908 | Computer 54
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Recurrent Edge-Convolutional Neural Network for Individual Identification Using Resting-state fMRI Data |
1Department of Electrical and Computer Engineering, University of California, Riverside, Riverside, CA, United States, 2Department of Bioengineering, University of California, Riverside, Riverside, CA, United States, 3Center for Advanced Neuroimaging, University of California, Riverside, Riverside, CA, United States |
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Convolutional neural networks extract local features effectively on volumetric data. For the ROI-based fMRI data, we proposed the recurrent edge-convolutional neural network to model spatial coactivation pattern and dynamics. Edge-convolution could depict the relation between hyper-neighborhoods based on pre-computed functional connectivity and |
| 3909 | Computer 55
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Empirical Mode Decomposition and Energy-Period Characteristics of Brain Networks in Group fMRI Resting-State Data |
1Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States, 2University of Colorado, Boulder, CO, United States, 3University of Management and Technology, Lahore, Pakistan, 4School of Public Health, University of North Texas, Fort Worth, TX, United States |
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In this project, we have studied resting-state networks using Empirical Mode Decomposition (EMD) to obtain energy-period information and compared results with the Maximal Overlap Discrete Wavelet Transform (MODWT) and the Short-Time Fourier Transform (STFT). We chose the STFT and MODWT for comparison with EMD, because the STFT is based on Fourier basis functions, the MODWT allows more adaptivity but still is model-based by wavelet functions, and EMD is model-free, adaptive and entirely data-driven. EMD showed the strongest relationship to frequency and energy content for different clusters of resting-state networks. |
| 3910 | Computer 56
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Human brain task-specific network mapping |
1Department of Radiology, Michigan State University, East Lansing, MI, United States |
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The activity of neural networks gives rise to simple motor behaviors as well as complex behaviors. To understand how the network activity is transformed into human behaviors, it is necessary to identify task-specific networks and analyze the dynamic network activity that changes with time. A functional area of unitary pooled activity (FAUPA) is defined as an area in which the temporal variation of the activity is the same across the entire area. Using the signal time course of a task-associated FAUPA may identify the functional network specific for the task. This study introduced a novel method to map task-specific networks. |
| 3911 | Computer 57
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Combination of Primary and Temporal Derivative Estimates in Functional MRI |
1Human MR Center, University of Massachusetts Amherst, Amherst, MA, United States |
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In the general linear model analysis of a task fMRI, the response latency was analyzed by including a derivative parameter estimate of the hemodynamic response function. The existing method of combining the two estimates was improved to provide a more appropriate sign and amplitude of the combined estimate, which was presented in 2018 ISMRM. The last year’s method has been further improved to determine the sign of the combined estimate using a coordinate transformation method and to regulate the variance of the combined estimate by introducing an ellipse model. The new WSA method was experimentally confirmed using the HCP database. |
| 3912 | Computer 58
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Multivariate group-level analysis to detect fMRI task activation |
1Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States, 2Departments of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, United States, 3Departments of Biostatistics and Epidemiology, University of North Taxes, Denton, TX, United States, 4University of Colorado Boulder, Boulder, CO, United States |
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A constrained multivariate model is introduced for fMRI group-level analysis to increase the sensitivity in group activation detection by incorporating local neighboring information. Results from both simulated data and real episodic memory data indicate that a higher detection sensitivity for a fixed specificity can be achieved in group-level activation detection with the proposed method. Applying multivariate analysis in both subject and group levels of analysis can further improve the activation detection performance. Statistical thresholds for significance of the group-inferences in the multivariate method are computed non-parametrically. |
| 3913 | Computer 59
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Spectral Entropy: A Useful Engineered Feature for Classification of fMRI Data Quality? |
1Department of Research, Nova Scotia Health Authority, Halifax, NS, Canada, 2Biomedical Translational Imaging Centre, Halifax, NS, Canada, 3Brain Networks & Neurophysiology Lab, Halifax, NS, Canada, 4Nova Scotia Department of Health and Wellness, Halifax, NS, Canada, 5Acquired Brain Injury, Nova Scotia Health Authority, Halifax, NS, Canada, 6Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada, 7Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada, 8School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada, 9Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada |
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This work evaluates the use of regularized spectral entropy (rSpecEn) as a potentially useful engineered feature for the classification of fMRI scan quality in real time. rSpecEn relies on the frequency sparsity of task-based fMRI signals, and a data-driven regularization method is employed to counteract unavoidable noise. Comparison to known measures of quality are used, as well as the use of fMRI scans with intentionally degraded quality. Sensitivity to fMRI data quality measures and an exploration of high accuracy scan quality classification are presented in this feasibility study. |
| 3914 | Computer 60
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Physiological Noise Correction in Simultaneous Brain and Spinal Cord fMRI |
1Stanford University, Palo Alto, CA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States |
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Effect of RETROICOR and RVHRCOR on brain and spinal cord activation is qualified from simultaneously acquired fMRI motor task data. tSNR and activation volume at subject-level are examined using (1) no physiological noise correction, (2) RETROICOR only, (3) RETROICOR and RVHRCOR. Although RETROICOR and RVHRCOR improve tSNR in both brain and spinal cord while removing false activation in brain, these corrections can remove true activation in spinal cord. Examination with and without physiological correction is the only known way to determine whether subject-level activation were removed by noise correction. In general, an increase in activation volume after physiological noise correction is a good indicator of little correlation between physiology and task. |
| 3915
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Computer 61
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Physiological noise removal in fast fMRI without separate physiological signal acquisition |
1Harvard-MIT Division of Health Sciences and Technology (HST), Cambridge, MA, United States, 2Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 3Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 5Department of Biomedical Engineering, Boston University, Boston, MA, United States, 6Department of Radiology, Harvard Medical School, Boston, MA, United States, 7Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States |
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Recent work has shown that commonly used methods to account for physiological noise and serial correlations in conventional fMRI are inadequate for fast (TR<500 ms) fMRI and may lead to incorrect inferences1. We created a model of physiological noise based on harmonic regression with autoregressive noise that utilizes the enhanced sampling of fast fMRI to estimate physiological noise directly from the fMRI data; therefore, it does not require physiological reference signals such as respiration. We found that our model performs as well as gold standard reference-based approaches in removing physiological noise and improves the detection of task-driven fMRI activity. |
| 3916 | Computer 62
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Improvement of functional sensitivity using multi-echo EPI and BOLD response based HRF model at 7T |
1Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Japan, 2Graduate School of Frontier Biosciences, Osaka University, Suita, Japan |
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To study amygdala function, we used multi-echo EPI sequence as fMRI at 7T to reduce the effects of local magnetic field inhomogeneity in the region. Additionally, to increase sensitivity, we modified a hemodynamic response function model from an empirical model. These methods allowed us to detect robust activation of the amygdala and brain areas related to emotional face discrimination tasks in addition to increased functional connectivity between them. Using an appropriate acquisition method and statistical model can improve sensitivity in regions whose signal is suffered by local magnetic field inhomogeneity in ultra-high field fMRI studies. |
| 3917 | Computer 63
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Oxygen and Glucose metabolism in connector hubs estimated from resting-state fMRI |
1Physics, Concordia University, Montreal, QC, Canada, 2PERFORM Centre, Montreal, QC, Canada, 3Biomedical Engineering, McGill University, Montreal, QC, Canada, 4Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States, 5Montreal Neurological Institute, McGill University, Montreal, QC, Canada, 6Montreal Heart Institute Research Institute, Montreal, QC, Canada |
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Connector hubs are highly functionally connected regions of the brain, allowing efficient distant communication between segregated modules. To study their metabolism we localized them from resting-state fMRI data using a Sparsity-based analysis method and estimated the number of functional networks associated with each voxel (K-hubness). We used quantitative MRI with gas manipulations to estimate baseline cerebral metabolic rate of O2 (CMRO2), cerebral blood flow, oxygen extraction fraction, and FDG-PET to estimate the resting cerebral metabolic rate of Glucose (CMRGlu). Our results showed a power-law model of the relationship between K-hubness and their CMRO2 and CMRGlu, confirming the metabolic efficiency of hubs. |
| 3918 | Computer 64
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Which lateralization index and which language task should we use in lateralization test? |
1Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University, Tochigi, Japan, 2Department of Radiology, Dokkyo Medical University, Tochigi, Japan |
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It is crucial to select a good language task in fMRI to examine the language lateralization. We examined the concordances of 6 lateralization indices (LIs) using 4 language tasks. We confirmed that our previously developed LI, AveLI, showed a better concordance of index values across 4 tasks. Also, the verb generation task showed a better concordance across the 6 LIs than other tasks. In addition, this task showed a plausible ratio of rightward asymmetry (5 out of 16 left/both-hand preferred). Thus, we concluded to conduct the verb generation task and compute AveLI as a robust index of the language lateralization. |
| 3919 | Computer 65
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An ALE meta-analytic comparison of verbal working memory tasks |
1Psychology, University of Georgia, Athens, GA, United States |
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The n-Back and Paced Auditory Serial Addition Test (PASAT) are common verbal working memory tasks (VWM). Activation Likelihood Estimation (ALE) meta-analyses examined n-Back and PASAT literature, revealing regions associated with salience, emotional processing, and VWM. Contrasts revealed differential dorsolateral prefrontal cortex, left posterior parietal cortex, and midline supplementary motor area activation between the tasks. Findings demonstrate the sensitivity of ALE meta-analysis to reveal similarities and differences associated with the cognitive and emotional aspects of VWM tasks. They provide the first glimpse into regions activated by the PASAT using meta-analyses that indicate potential overlapping utility. |
| 3920 | Computer 66
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Assessment of Global and Regional Difference of Resting State Cerebral Vascular Reactivity index in Patient with Brain Tumor |
1Radiology, MSKCC, New York, NY, United States, 2medical physics, MSKCC, New York, NY, United States |
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The resting state fMRI (rfMRI) was used to estimate the BOLD signal change in response to natural breathing to measure the impairment of cerebra vascular reactivity (CVR) due to the presence of tumor. CVR associated values were obtained from the low frequency fluctuation of rfMRI and averaged over whole brain and tumor region of interests to measure the frequency related CVR properties respectively. These results indicate the existence of inter/intrasubject variability in low frequency and more sensitivity of the whole brain homogeneity to frequency rather than tumor. CVR mapping can determine the area of potential neuro-vascular uncoupling in the brain. |
| 3921 | Computer 67
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Abnormal brain network configuration associated with posttraumatic stress disorder: a novel combined approach using graph theory and scaled subprofile modeling |
1Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada, 2Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg, MB, Canada, 3Department of Psychology, University of Manitoba, Winnipeg, MB, Canada, 4Department of Psychology, Ryerson University, Toronto, ON, Canada |
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Posttraumatic stress disorder (PTSD) is a prevalent psychiatric disorder with etiology and symptom expression that can vary greatly among patients. Currently, no objective clinical biomarker exists for assessing clinical severity and treatment response. In order to develop a reliable method of characterizing PTSD, we must understand how the brain changes in response to trauma. We propose a novel approach, combining graph theory analysis and scaled subprofile modeling (SSM) to identify degree centrality and its group-discriminating topographical patterns, respectively. This method has been successful in distinguishing fMRI scans of PTSD patients from trauma-exposed controls, and resulted in a reliable PTSD-related network configuration. |
| 3922 | Computer 68
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Diagnosing first-episode depression with high-order regional homogeneity |
1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, chapel hill, NC, United States, 2The First School of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China, 3Department of Radiology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China |
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The brain is a dynamic biosystem where the regions communicate with each other in a time-varying and adaptive way. Recently, abnormally varied brain statuses in brain diseases have been demonstrated with dynamic functional connectivity (FC) and a newly developed technique, high-order FC, which measures synchronization of the FC dynamics, providing a valuable way to characterize high-level brain function. However, there is a lack of method in quantification of local synchronization of the FC dynamics, another important facet of the high-level brain functional organization that could underpin complex regional brain activities. To this end, we propose a new method called high-order regional homogeneity (high-order ReHo) to evaluate such complex organizations of the local FC dynamics. We demonstrated that such a metric is more sensitive compared to the traditional low-order ReHo approach in individualized depression classification. |
| 3923 | Computer 69
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Brain Activity Mapping Based on Low-Frequency Fluctuations of the Resting-State BOLD Signal: Comparing Healthy Elderly to Mild Cognitive Impairment and Alzheimer’s Disease |
1Western University, London, ON, Canada, 2University of Toronto, Toronto, ON, Canada, 3Ontario Brain Institute, Toronto, ON, Canada, 4Sunnybrook Health Sciences Centre, Toronto, ON, Canada |
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Our group recently introduced a neuronal activity (NA) metric based on a texture feature of the low-frequency fluctuations within the resting-state BOLD signal. This NA measure was associated with decreased glucose metabolism in mild Alzheimer’s disease (AD) measured by FDG-PET. To improve the sensitivity of this NA metric we introduce two variations achieved by rigorously regulating (using cross-correlation and cross-covariance) the amplitude of the BOLD signal oscillations derived from the constituent neuronal components. These novel metrics were evaluated in people with mild cognitive impairment and AD (N=14) demonstrating lower neuronal activity compared to healthy elderly (N=14). |
| 3924 | Computer 70
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Relative assessment of language lateralisation with fMRI: evaluation of a novel threshold-independent method |
1Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Department of Neuroradiology, King's College Hospital, London, United Kingdom, 3Department of Medical Physics and Bioengineering, NHS Highland, Inverness, United Kingdom |
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The assessment of language lateralisation with fMRI using the laterality index is limited by the dependence of the results on the chosen activation threshold. To overcome this limitation, different threshold-independent laterality index calculations have been introduced. This work proposes a new method and evaluates how it performs in comparison with three previously reported methods. The methods were evaluated on fifteen healthy subjects who performed picture naming, verb generation, and word fluency tasks. The novel method is simple to implement, fast, robust, reproducible, and compares well with the others in differentiating strong from weak lateralisation on both hemispheric and regional scales. |
| 3925 | Computer 71
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Automatic classification of Type 2 diabetes mellitus with and without microangiopathy via feature selection and support vector machine based on resting-state fMRI |
1Department of Radiology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China, 2Clinical Science, Philips Healthcare, Shanghai, China |
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Type 2 diabetes (T2DM) mellitus is associated with microvascular complications which can increase risk of cognition impairment and dementia. Recently, machine learning, espicailly support vector machine, were introduced to functional MRI studies in individual classification of diseases. In current study, we used support vector machine to perform individual classification of T2DM with (T2DM-C) and without (T2DM-NC) microangiopathy using ALFF and ReHo features based on rs-fMRI data. The selected features were determined to be key features for classification between groups using recursive feature elimination and may be associated with abnormalities of the spontaneous brain activity in T2DM-C |
| 3926 | Computer 72
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Schizophrenia Patients Exhibit Aberrant Phase-Space Embedding of CEN/DMN Interaction |
1Department of Electrical and Computer Engineering, University of California, Riverside, Riverside, CA, United States, 2Department of Bioengineering, University of California, Riverside, Riverside, CA, United States |
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A proper method for distinguishing Schizophrenia (SZ) patients from people belonging to normal controls is invaluable for diagnostics. Standard techniques of identifying SZ patients include a variety of clustering-based methods. For example, those based on |
| 3927 | Computer 73
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Construction of high precision and resolution render files for SPM and XJview |
1Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 2Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China, 3Stanford University, Stanford, CA, United States, 4Department of Linguistics, University of Hong Kong, Hongkong, China, 5McGovern Institute for Brain Research, Peking University, Beijing, China |
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Render file is one of the typical formats used to display brain surface in brain analysis software such as SPM and XJview. However, current images of render files included in SPM and XJview have issues of low resolution, blurring, and inaccurate spatial localization. Therefore, it is necessary to create a render file with high precision and resolution to better display the activation results generated in SPM. In this study, a set of improved render files were constructed using a modified ICBM_2009c template. |
| 3928 | Computer 74
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Real-time fMRI amygdala neurofeedback training reduces depression symptoms and appears to normalize amygdala and hippocampal volumes |
1Laureate Institute for Brain Research, Tulsa, OK, United States, 2Electrical and Computer Engineering, University of Oklahoma, Tulsa, OK, United States, 3Department of Psychiatry, University of Pittsburg, Pittsburg, PA, United States, 4Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States |
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We evaluated structural brain changes as a result of real-time fMRI neurofeedback (rtfMRI- |
| 3929 | Computer 75
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Live figures in BioImage Suite Web for improved results, visualizations, and data transparency |
1Yale School of Medicine, New Haven, CT, United States |
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Figures of neuroimaging results are typically static. In other words, these figures only show the slices and statistical information that the creator of the figures previously selected. However, other researchers may want to visualize other information. Here, we present “live figures” using the BioImage Suite Web (BISWeb) software. “Live figures” represent an encapsulation of all information used to make the figure (i.e. images, slice, thresholds, colormap, etc) that is than saved to a file and can be loaded back into BISWeb. The only requirement to view these “live figures” is a modern web-browser. No other software needs to be installed. |
| 3930 | Computer 76
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Quiet, Low-Distortion Whole Brain T2-BOLD fMRI at 7T |
1MR Applied Sciences Lab West, GE Heathcare, San Francisco, CA, United States, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 3MR Applied Sciences Lab Europe, GE Heathcare, Munich, Germany |
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EPI-based 7T fMRI techniques suffer from spatial distortions in areas of B0 inhomogeneity, signal dropout near air-tissue boundaries, and gradient induced acoustic noise can be as high as 115-120dB. We have developed fast, quiet, low-distortion whole brain 7T fMRI by using the T2-prepared Rotating Ultrafast Imaging Sequence (RUFIS). RUFIS is a ZTE technique with low gradient switching, so it does not suffer from many of the problems of EPI-based methods. It has no spatial distortions and signal dropout, and is 40dB quieter than standard EPI-based technique. Whole-brain 3mm isotropic results for resting state and task-based 7T fMRI experiments are shown. |
| 3931 | Computer 77
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Rotated Stack of Spirals 3D RARE for Single-shot Volumetric ASL Acquisition |
1Division of MRI research, Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Diagnostic Imaging and Radiology, Children’s National Medical Center, Washington, DC, United States, 3Global MR Applications and Workflow, GE Healthcare, Calgary, AB, Canada, 4Global MR Applications and Workflow, GE Healthcare, Boston, MA, United States |
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Single-shot accelerated volumetric Arterial Spin Labeling is desirable for studies of flow and function modulation but it typically degrades image quality relative to multi-shot interleaved acquisitions. We report a Stack of Spirals RARE acquisition with rotation of spirals between slice encodes and repetitions. This acquisition supports high quality single-shot reconstruction with 3D parallel imaging/compressed sensing while retaining the ability to perform conventional interleaved reconstruction of time averaged perfusion. Application of the sequence to quantification of resting state network fluctuations is demonstrated. |
| 3932 | Computer 78
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Improving the sensitivity of Spin-Echo fMRI at 3.0 T by highly accelerated acquisitions |
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany |
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Spin-echo fMRI can be highly advantageous compared to gradient-echo fMRI with respect to magnetic field inhomogeneity artefacts, but is seldomly used for BOLD imaging due to its inferior sensitivity. The presented spin-echo implementation of a highly accelerated gradient-echo fMRI pulse sequence therefore aims to improve the sensitivity of spin-echo fMRI while profiting from a reduction of inhomogeneity-induced artefacts. Preliminary measurements using a temporal resolution of 134 ms for whole brain imaging show less signal dropout when compared to the gradient-echo counterpart, as well as an increase in the number of significantly activated voxels compared to the unaccelerated readout. |
| 3933 | Computer 79
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Implementing human line-scanning fMRI: Initial results of ultra-high temporal and spatial resolution fMRI |
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Spinoza Centre for Neuroimaging Amsterdam, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands, 3Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 4Graduate Training Centre of Neuroscience, Tuebingen, Germany |
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Here we present the initial results on implementing human line-scanning fMRI with the purpose of obtaining ultra-high temporal and spatial resolution data of hemodynamic changes in the human brain. This technique could yield novel insights for fundamental neuroscience on laminar information flow, but also for better understanding of microvascular pathophysiological mechanisms in a wide range of brain disorders. |
| 3934 | Computer 80
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Sub-Millimeter Resolution Compressed Sensing GRASE for T2-Weighted Functional MRI at 7 Tesla |
1University of California, Berkeley, Berkeley, CA, United States, 2Advanced MRI Technologies, Sebastopol, CA, United States |
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At high magnetic field, 7T and above, T2-weighted fMRI has drawn attention for its high specificity in columnar and layer specific fMRI by minimizing draining vein effects compared to T2*-weighted GE-EPI based fMRI. 3D inner-volume gradient and spin echo (3D-GRASE) has been proposed and used for sub-millimeter resolution. However, reduced field-of-view (FOV) imaging in general has disadvantages compared to GE-EPI: 1) small FOV, 2) T2 induced blurring, both along the partition direction, and 3) low signal-to-noise ratio (SNR) from long TE with EPI readouts. To address both issues, 3D GRASE is extended to volumetric ky-kz random undersampling followed by performing CS for signal recovery (3D CS-GRASE). The ky-kz undersampling extends volume coverage without compromising the blurring while enhancing SNR due to short TE from inplane undersampling. |
| 3935 | Computer 81
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MR Imaging of Current Vector Fields Induced by TDCS |
1University of Michigan, Ann Arbor, MI, United States |
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The present study introduces a method to measure the full current density vector field induced by a transcranial direct current stimulation (TDCS) device. Our proposed method uses MRI to measure components of the magnetic field with the phantom/head in different positions. We introduce the theory and demonstrate the method on a current phantom and a human volunteer. |
| 3936 | Computer 82
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Effect of Coil Compression on tSNR, DVARS and Computation Time on Simultaneous Multi Slice Imaging |
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, 4GE Healthcare, Waukesha, WI, United States |
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Simultaneous multi-slice (SMS) imaging requires the application of a parallel imaging algorithm for image unaliasing. Including coil compression in SMS image reconstruction offers a benefit of reducing the computational load of the reconstruction algorithm and can better condition the matrix which is inverted in the unaliasing algorithm. The goal of this abstract is to evaluate the optimal level of coil compression to utilize with slice-ARC in Human Connectome Project (HCP) compliant, and other SMS protocols with a Nova Medical 32-channel head coil. It was found that, for all levels of coil compression, application of the compression algorithm yielded a benefit in reconstruction performance. Additionally, it was found that the application of coil compression does not significantly impact the selection of a CAIPI shift factor unless a coil compression of 50% or greater is used. |
| 3937 | Computer 83
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Time variant cardiac noise correction in resting state fMRI without physiologic noise measures |
1Radiology, Cleveland Clinic, Cleveland, OH, United States |
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The cardiac and respiratory response functions derived from RETROICOR have substantial variation. We found the cardiac response function is phase, or time shifted across the brain while the respiratory function has a fixed phase, but changes polarity across the brain. Based on this finding, we propose a cardiac and respiratory noise correction method in rsfMRI data without external cardiac and respiratory fluctuation measures, and compare its performance to the RETROICOR model. |
| 3938 | Computer 84
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Olfactory functional MRI (fMRI) using T2-prepared BOLD fMRI at ultra-high field (7T) |
1F.M. Kirby Research Center, Kennedy Krieger Institute, Baltimore, MD, United States, 2Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 6Lou Ruvo Center for Brain Health, Cleveland Clinic, Las Vegas, NV, United States, 7Radiology, Johns Hopkins Hospital, Baltimore, MD, United States |
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The olfactory cortex is difficult to image with conventional EPI-fMRI due to susceptibility artifacts especially at 7T. T2-prepared (T2prep) fMRI is an alternative method to reduce such artifacts. Here, we show that T2prep-fMRI offers superior temporal signal-to-noise ratio in the olfactory cortex over EPI-fMRI at 7T. The signal characteristics detected using T2prep-fMRI during short (6s) and long (60s) olfactory stimulation were consistent with literature. During the long stimulus, fMRI signals in the olfactory cortex returned to baseline in 5-10s, and activation of secondary olfactory regions (insular, orbitofrontal) were observed, which can be attributed to habituation effects in the olfactory system. |
| 3939 | Computer 85
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Inter-site repeatability of motor-visual task fMRI responses at 7 Tesla |
1Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 3Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 4Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, 5Imaging Centre of Excellence, University of Glasgow, Glasgow, United Kingdom |
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This work studies cross-site variability in 7 Tesla task fMRI measurements, collected as part of a “travelling heads” study. Participants were scanned at the five human UK 7 Tesla MRI sites, and results are presented from four of these sites. A motor-visual task was performed at each site with acquisitions matched as closely as possible. Despite some apparent differences in tSNR , we demonstrate that it is possible to achieve good agreement across sites. The %BOLD coefficient of variation of 0.1-0.2 across sites was similar to the within-site ranges. This work sets the foundation for multi-site 7 Tesla clinical trials. |
| 3940 | Computer 86
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Effect of spatial smoothing of the data acquired with Multiband and 3D EPI in functional MRI. |
1Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, United Kingdom, 2UCL Institute of Cognitive Neuroscience, London, United Kingdom |
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2D-EPI Multiband and 3D-EPI are commonly used approaches to acquiring high-resolution fMRI scans while maintaining reasonable scan times. In this work, the relative merit of these methods was investigated with respect to acceleration factor, coverage, physiological noise correction, and smoothing kernel. Both methods performed equivalently in term of activation t-scores and temporal SNR, regardless of the coverage or acceleration when no smoothing was applied. However, 2D MB benefited more from smoothing than 3D. Our hypothesis was that this was due to a higher degree of spatial correlation in the noise for the 3D acquisition and was confirmed by additional tests. |
| 3941 | Computer 87
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An Optimized Processing Procedure for Fetal Resting State Imaging |
1Department of Neuroradiology, San Raffaele Scientific Institute, Milan, Italy, 2Department of Gynecology, San Raffaele Scientific Institute, Milan, Italy, 3Department of Nuclear Medicine, San Raffaele Scientific Institute, Milan, Italy |
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Human fetal brain development is marked by the rapid growth of connections between brain structures during the last trimester of pregnancy. Crucially, data processing of fetal rs-functional scans (rs-fMRI) results largely affected by high degrees of movement, which impose severe constraints on interpretation of functional activation patterns leading to potentially biased results. In this work we present a standardized yet flexible preprocessing and normalization procedure allowing for data loss minimization (i.e. allowing to preserve the highest amount of volumes while consistently excluding outliers) and thus fostering reliable group-level inferences. |
| 3942 | Computer 88
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Which multiband factor should you choose for your resting-state fMRI study? |
1Biostatistics and Bioinformatics, Emory University Rollins School of Public Health, Atlanta, GA, United States, 2Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 3Joint Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States |
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Multiband / simultaneous multislice increases the temporal resolution in resting-state fMRI but at the cost of noise amplification, which may result in erroneous estimates of correlation-coefficient based functional connectivity. We examined functional connectivity in resting-state scans from ten subjects with multiband factors ranging from two to twelve. The standard deviation of voxel time series varies across space, which is in part due to noise amplification. Multiband acceleration tends to decrease estimates of functional connectivity, particularly for correlations involving subcortical regions. Consequently, it may be challenging to disentangle low neural activity from high noise amplification. |
| 3943 | Computer 89
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EPI based MR thermometry and real-time monitoring for parallel RF transmission at 7T |
1NICT, Suita-shi,Osaka, Japan, 2RIKEN Center for Brain Science, Wako, Japan |
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A novel method for MR thermometery and real-time temperature monitoring is developed. Using the change in phase for fat between first and third navigator lines of EPI, the proposed method allows estimating the change in phase for water caused by the change in base frequency at echo time of EPI. Scanning a fat bag placed beside a phantom in different slices allow image reconstruction from the calculated phase difference. The proposed method does not require separate scans for fat and water allowing an effective monitoring of in vivo SAR for ensuring the safety of experimental subjects especially in parallel-transmit systems. |
| 3944 | Computer 90
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Silent fMRI with visual and auditory stimulation using 3D radial T2*-weighted ZTE-BURST sequence |
1IMT School for Advanced Studies, Lucca, Italy, 2IMAGO7 Foundation, Pisa, Italy, 3IRCCS Stella Maris, Pisa, Italy, 4Italian National Institute of Nuclear Physics, Pisa, Italy, 5GE Healthcare, Munich, Germany |
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Besides being a major cause of patient discomfort, acoustic scanner noise (ASN) represents one of the main confounding factors in fMRI with auditory stimulation and in resting state conditions. The recent development of silent T2*-weighted MR sequences may open up new possibilities in the study of brain function in a quieter environment offering novel tools of acquisition, alternative to EPI. In this feasibility study we aim to produce and evaluate BOLD activity maps at 7T using a novel 3D radial T2* sequence (ZTE-BURST). |
| 3945 | Computer 91
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T1w MPRAGE transformation based on distortion-matched anatomy for high-resolution fMRI |
1Laboratory of Brain Function Analysis and Imaging, CiNet, NICT, Suita City, Osaka, Japan |
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We demonstrate transformation of T1w MPRAGE anatomy into functional space based on DAIREPI T1w-like reconstruction2. This transformation allows comparison of the respective tissue segmentations for highlighting brain regions affected by signal losses and distortions in functional imaging. Effective evaluation of functional imaging at 7T require such an offline quality check procedure to correctly identify the cause of missing hemodynamic activity in high-resolution fMRI at an individual subject-level. This proposed procedure offers a new way to perform analysis of high-resolution fMRI on a high-contrast T1w anatomy and cortical surface in the native EPI space. |
| 3946 | Computer 92
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Comparison of continuous sampling with active noise cancellation and sparse sampling for cortical and subcortical auditory fMRI |
1Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 2NIHR Nottingham Biomedical Research Centre, Nottingham, United Kingdom, 3Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, United Kingdom, 4University of Nottingham Malaysia, Jalan Broga, Selangor Darul Ehsan, Malaysia, 5Manchester Centre for Audiology and Deafness (ManCAD), University of Manchester, Manchester, United Kingdom, 6NIHR Manchester Biomedical Research Centre, Manchester, United Kingdom, 7Department of Psychology, Lancaster University, Lancaster, United Kingdom |
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We compared cortical and subcortical auditory BOLD fMRI responses to epochs of broadband noise acquired using continuous sampling with active noise cancellation (TR = 2s) to sparse sampling (TR = 8s, 1993ms acquisition with 6007ms silence) in a repeated measures factorial design. High resolution (1.5 mm3) 3 Tesla fMRI data were acquired using multiband 2 and corrected for physiological noise and image distortions. BOLD beta estimates are compared for onset, offset and sustained auditory fMRI responses for both sampling schemes. We report the strengths and weaknesses of the two sampling methods. |
| 3947 | Computer 93
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Improving k-space physiological noise correction with motion correction in fMRI studies |
1fMRI support unit, RIKEN Center for Brain Science, Wako-shi, Japan, 2Laboratory for Cognitive Brain Mapping, RIKEN Center for Brain Science, Wako-shi, Japan |
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Although physiological noise correction could improve the signal quality, the signal contamination caused by subject motion would affect the ability to remove the noise. This study aims to characterize the impact of motion on the physiological noise correction in k-space and improve k-space physiological noise correction performance. The strength of motion significantly influenced the average tSNR after k-space physiological noise correction. By removing motion effect in advance, it is possible to make k-space physiological noise correction more effective. |
| 3948 | Computer 94
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SSFP-fMRI: Radial reading helps to Improve Temporal SNR |
1School of Cognitive Science, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran (Islamic Republic of), 2Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran (Islamic Republic of) |
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SSFP allows us to have functional contrast close to spin-echo, but it suffers from low temporal-resolution. Increasing |
| 3949 | Computer 95
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Optimization of Simultaneous Multi-slice Imaging with Autocalibrating Reconstruction for Cartesian Imaging Parameters for Human Connectome Type Protocol |
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, 4GE Healthcare, Waukesha, WI, United States |
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The optimal parameterization of simultaneous multi-slice (SMS) unaliasing kernel fitting with autocalibrating reconstruction for cartesian imaging (ARC) is not obvious. Here we systematically varied five variables that parameterize this calibration process to empirically determine optimal values for human connectome project (HCP) harmonized image reconstruction. Low levels of regularization, moderate sizes of ky-kernels, and increased numbers of ky-calibration points yield improved unaliasing performance. |
| 3950 | Computer 96
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Evaluation of simultaneous multi-slice EPI acquisition with an 8-channel coil for resting state functional MRI |
1Department of Radiology, University of Washington, Seattle, WA, United States, 2Department of Anatomy and Medical Imaging & Centre for Brain Research, University of Auckland, Auckland, New Zealand, 3Department of Radiology, Stanford University, Stanford, CA, United States |
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Simultaneous multi-slice (SMS) imaging has shown to be a promising tool for improving the efficiency of resting state fMRI (rs-fMRI). As the multi-slice acceleration factor in SMS increases, so does the temporal resolution, allowing increased sensitivity of rs-fMRI measurements. However, to achieve high multi-slice acceleration factors, SMS typically uses higher channel (>=32) receiver coils that may not be available in many research and clinical settings. In this study, we explored the efficacy of using SMS with a typical 8-channel receiver coil for rs-fMRI. Upon employing the slice orientation that maximizes the coil sensitivity variation along the slice direction, we were able to acquire high temporal resolution (TR=400 ms) rs-fMRI data. Compared with the conventional-EPI acquisition (TR=2000 ms), the proposed SMS-EPI acquisition provided superior sensitivity and test-retest reliability for rs-fMRI. |
| 3951 | Computer 97
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The impact of gradient spoiling on the temporal stability of rapid 2D BOLD EPI |
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Siemens Medical Solutions USA Inc., Charlestown, MA, United States, 4Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Short-TR BOLD fMRI studies have increased in popularity due to the advancement of simultaneous multi-slice (SMS) techniques and the many advantages afforded by rapid sampling. However, in rapid imaging of a single slice, disruptions to the steady-state from physiological sources can result in large temporal variability in long-T2 tissues, primarily around cerebrospinal fluid. We investigated the sources of this variability and how they translate from single-slice to whole-brain SMS-based fMRI. |
| 3952 | Computer 98
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Global Signal Regression in Resting-state fMRI Pre-processing Improves Classification Accuracy |
1Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China, 2National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China, 3University of Chinese Academy of Sciences, Beijing, China, 4Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China, 5Department of Psychiatry, Xijing Hospital, The Fourth Military Medical University, Xi'an, China, 6Zhumadian Psychiatric Hospital, Zhumadian, China, 7Peking University Sixth Hospital / Institute of Mental Health, Beijing, China, 8Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China, 9Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China, 10Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, China, 11Department of Psychology, Xinxiang Medical University, Xinxiang, China, 12Center for Life Sciences / PKU-IDG / McGovern Institute for Brain Research, Peking University, Beijing, China, 13Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, 14Queensland Brain Institute, University of Queensland, Brisbane, Australia, 15CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Automation, Beijing, China |
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Global signal regression (GSR) is under debate whether or not influences the interpretation of functional connectivity (FC). However, few studies have compared and discussed the classification performance of GSR on a large dataset. We used a large dataset of resting-state fMRI data with 1082 subjects to test whether GSR influences the FC-based classification performance. We reached 81.35%-84.36% test accuracy using nested cross-validation. We tested the contribution of GSR, feature whitening and classifiers to the classification accuracy variance using three-way ANOVA and found significant main effects only for the GSR factor (F=7.14, P=0.0089). The results suggest GSR improves the classification accuracy. |
| 3953 | Computer 99
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On the Reproducibility of In-vivo Temporal Signal-to-Noise Ratio as a Quality Assurance Measure of fMRI Data |
1SNS Lab, University of Zurich, Zurich, Switzerland, 2Budapest University of Technology and Economics, Budapest, Hungary, 3Brain Imaging Centre, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary |
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Temporal signal-to-noise ratio (tSNR) is commonly used as a quality assurance measure of fMRI data. The aim of this study was to investigate how reproducibly tSNR maps could be collected in-vivo. We collected 16 fMRI time series in several sessions on two different days and calculated tSNR maps for each. The variability was evaluated over all runs, runs within the same session, runs between sessions and runs between days. Reproducibility turned out to be very poor, which precludes using tSNR as an outcome measure for testing variables that are expected to provide modest but otherwise important improvements to data quality. |
| 3954 | Computer 100
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Denoising in task fMRI |
1Radiology, UZ Brussel, Brussels, Belgium |
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To improve the outcome of task fMRI analyses, we compared the result maps obtained following a modulated analysis pipeline with despiking and CompCor added as denoising steps, with those obtained following the standard analysis pipeline. The data was taken from 5 studies. We focused on the overlap between the obtained individual findings, between the individual and group results and between the findings of 2 fMRI sessions. Our results revealed a reduction in false results in the ventricles, but failed to show an increased repeatability of fMRI results after the denoising. In conclusion, denoising prior to the statistical analysis seems advisable. |
| 3955 | Computer 101
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Multi-Excitation MRE in Aging Human Brain: Estimation of Direction-Dependent Mechanical Properties |
1Biomedical Engineering Department, Illinois Institute of Technology, Chicago, IL, United States, 2Beckman Institute, University of Illinois at Urbana-Champaign, Champaign, IL, United States, 3Department of Mechanical & Aerospace Engineering, Rutgers University, Piscataway, NJ, United States |
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Healthy aging affects the local mechanical properties of the human brain tissue but their estimation remains a challenge, especially in strongly anisotropic white matter regions. This study merges previous MRE aging research involving high-resolution, full-coverage, and multi-excitation MRE imaging with the ability to estimate anisotropic shear moduli locally. We identified important anisotropic differences in the storage modulus in the corpus callosum, which help differentiate old from the young. |
| 3956 | Computer 102
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High-resolution one-dimensional shear wave MR elastography at 78 microns: initial results in skin imaging in vivo. |
1Department of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Department of Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, 3Department of Chemical Engineering, IQS School of Engineering, Universitat Ramon Llull, Barcelona, Spain, 4Faculty of Health Sciences, University of Southampton, Southampton, United Kingdom, 5Philips Healthcare, Guildford, United Kingdom, 6King's College London, London, United Kingdom, 7Laboratory for Vascular Translational Science, INSERM, Paris, France |
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Imaging the biomechanical properties of thin structures with MR is challenging due to the generally low spatial resolution of MR elastography. In this study, we discuss a novel approach for imaging these structures using high-resolution motion sensitised pencil beam MRE at 78 microns to determine transient shear wave propagation. Initial results describe the application of this approach in phantom and skin imaging. |
| 3957 | Computer 103
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In vivo Assessment of Gray Matter Stiffness and Perfusion in the Human Brain |
1Department for Diagnostic Physics, Oslo University Hospital, Oslo, Norway, 2The Intervention Center, Oslo University Hospital, Oslo, Norway, 3Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom, 4Inserm U1148, LVTS, University Paris Diderot, Paris, France |
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MR Elastography (MRE) is an emerging imaging technique used to quantify the stiffness and viscosity of tissue. Few studies have investigated the relationship between these biomechanical properties and brain perfusion. If understood, this could provide valuable new insight in diseases that alter biomechanical properties or functionality. In our study we assess the cerebral blood flow and the tissue stiffness of gray matter in healthy volunteers. We find that in cortical gray matter, both the cerebral blood flow and the shear storage modulus G’ was higher than in deep gray matter. |
| 3958 | Computer 104
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Characterization of fibril aggregates in ex vivo rat brain with multi-frequency MR Elastography – Preliminary results |
1Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France, 2Univ. Lyon, Lyon Neuroscience Research Center, CNRS UMR 5292, INSERM U1028, Univ. Lyon 1, Lyon, France, 3INSERM U 1148, Laboratory of Vascular Translational Science; X. Bichat Hospital University Paris Diderot, Paris, France |
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Fibrils are biomarkers for early stages of dementia. In this work, α-synuclein fibrils were injected in rat striatum. Brains were imaged ex-vivo using multi-frequency MR Elastography. Estimation of the real part kr of the complex wave number was made for each studied frequency in ROIs surrounding the inclusion, a contralateral control injection and the whole brain. Exponent of the frequency power law was derived from kr maps acquired at different frequencies. No difference was observed between kr values for the different ROIs, but the exponent was more important at the fibrils location, potentially indicating that multi-frequency MRE can detect fibrils. |
| 3959 | Computer 105
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Real-time magnetic resonance elastography: application for monitoring lower leg muscle function during plantar flexion |
1Charité Universitätsmedizin Berlin, Berlin, Germany |
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Real-time elastography is well established in ultrasound but has not yet been achieved in MRI. Real-time elastography would be desirable for studying processes that are not easily repeatable or reproducible such as skeletal muscle function. Therefore, we developed a new concept in magnetic resonance elastography (MRE) based on stroboscopic wave sampling and single-shot spiral-k-space acquisition to push temporal resolution of MRE towards real-time elastography. Application of the new method is demonstrated in the lower leg muscles of healthy volunteers. |
| 3960 | Computer 106
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In-Vivo Quantification of Aortic Stiffness using a Multi-Slice Spin-Echo Echo-Planar Imaging Sequence: A Comparison to a Gradient-Recalled Echo Sequence |
1Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, United States, 2Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States, 3Siemens Healthcare USA, Columbus, OH, United States, 4Internal Medicine-Cardiovascular Division, The Ohio State University Wexner Medical Center, Columbus, OH, United States |
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Aortic stiffness is an important biomarker of cardiovascular diseases. Magnetic Resonance Elastography (MRE) is a non-invasive tool for measuring in-vivo aortic stiffness. Gradient-Recalled Echo (GRE) MRE sequences are widely employed for aortic MRE. However, GRE MRE sequences are sensitive to T2* decay, leading to signal loss and lower Signal-to-Noise Ratio (SNR). In this work, a cardiac-gated Spin-Echo Echo-Planar Imaging (SE-EPI) MRE sequence was developed and validated against GRE MRE. Similar aortic stiffness was observed between the two techniques. Moreover, shorter scan time, higher first-harmonic amplitude, and Octahedral Shear Strain-Based SNR (OSS-SNR) were achieved using SE-EPI MRE (p<0.05). |
| 3961 | Computer 107
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The contribution of cells and extracellular matrix to liver viscoelasticity: Histological analysis combined with multifrequency MR elastography and diffusion weighted imaging in rat liver specimens |
1Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany, 2University of Pennsylvania, Philadelphia, PA, United States |
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The effect of freezing/thawing at -20°C and -80°C on liver tissue was analyzed by diffusion-weighted imaging (DWI), multifrequency MR elastography (MRE) and histological methods. Freezing-induced deterioration of cell membranes, detachment of sinusoidal endothelial cells and disorganization of sinusoidal collagen together with reduced water diffusion and macroscopic shear modulus and affected tissue viscosity. Histological analysis revealed that collagen structures at the space of Disse are better preserved at -80°C than -20°C which was mirrored by tissue viscosity indicating the sensitivity of multifrequency MRE to microstructural changes of soft biological tissues. |
| 3962 | Computer 108
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Analysis and Maximization of SNR in MR Elastography Inversion |
1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey |
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Reconstructed elastography maps suffer from noise due to derivative operations in the inversion algorithms. Considering the noise on the complex MRI signal, SNR of the reconstructed elastogram is derived analytically for k-MDEV inversion. Verified SNR derivations by Monte Carlo Simulations, an SNR-weighted k-MDEV inversion was proposed to maximize SNR of the elastogram. Quality of the proposed reconstruction was assessed by estimation error, noise performance and edge response analyses. SNR of the elasticity improved twice as the conventional method. Results on phantom and human liver data are also provided. As future work, this analysis will be performed for other inversion methods. |
| 3963 | Computer 109
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Tabletop MR Elastography (MRE): Preliminary Results Towards an Assessment of Frozen Tissue Bank Samples. |
1Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 2Radiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany |
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Tabletop magnetic resonance elastography (MRE) at 0.5 Tesla was recently introduced as a low-cost technique for assessing mechanical properties of small tissue samples. Frozen tissue banks potentially facilitate access to large amounts of specimens. Therefore, we aimed to characterize changes |
| 3964 | Computer 110
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In Vivo Cardiac MR Elastography with a Gravitational Transducer |
1Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom, 2Philips Healthcare, Guildford, Surrey, United Kingdom, 3Amsterdam UMC, Amsterdam, Netherlands, 4Guy's and St.Thomas' NHS Foundation Trust, London, United Kingdom, 5Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, MI, United States |
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MR Elastography is beneficial in measuring the stiffness values of tissues which can change in disease. Nevertheless, cardiac MR Elastography is not only challenging from the acquisition side but also from the reconstruction side because of the higher stiffness values expected in the cardiac muscle compared to the other organs in which MR Elastography is commonly applied. Here, we present data in healthy subjects and a patient acquired with the gravitational transducer with a novel synchronising strategy in combination with a single-shot SE-EPI-MRE sequence employing second-order motion compensated motion encoding gradients with and without ZOnal Oblique Multislice Imaging. |
| 3965 | Computer 111
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Blip-Up Blip-Down Correction for Head MR Elastography |
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Mayo Clinic, Rochester, MN, United States |
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Geometric distortion in echo planar imaging-spin echo (EPI-SE) images caused by a non-uniform B0 field remains an issue in clinical imaging. In elastography, this geometric distortion leads to systematic errors in stiffness estimates. While blip-up blip-down correction is routinely used in diffusion imaging in the head, this correction is not used in MR elastography. The purpose of this work is to assess the effect of applying distortion correction on elastography scans and the resulting stiffness estimates. We show that the corrections provide reduced variability in stiffness maps with no additional acquisition time required. |
| 3966 | Computer 112
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Online platform for extendable server-based processing of magnetic resonance elastography data. |
1Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 2Insitute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany, 3Department of Radiology, The Ohio State University, Columbus, OH, United States |
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The variety of reconstruction algorithms throughout the MRE community makes it difficult to compare the validity and strengths of these methods. We propose an extendable online platform, combining multiple processing methods to facilitate a direct comparison. The platform is implemented as a Java web application, designed to run every command line program. Processing is done on the server, configured through the easy-to-use web-interface. Currently, state-of-the-art MRE reconstruction algorithms, multiple pre-processing methods, automated data import as well as sample data of phantom-MRE and in-vivo MRE are included. We aim at extension of the platform and an automation of adding new methods. |
| 3967 | Computer 113
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Cluster based analysis of fMRE data: computing heterogeneous regions of visual activation through correlation analysis. |
1Department of Nuclear medicine and Radiobiology, University of Sherbrooke, Sherbrooke, QC, Canada, 2ESEO (École Supérieure d'Électronique de l'Ouest), ANGERS, France, 3MR Clinical Science, Philips Healthcare, Markham, ON, Canada, 4Department of Mechanical Engineering, University of Sherbrooke, Sherbrooke, QC, Canada |
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A method for more completely assessing the regions of activation in functional Magnetic Resonance Elastography is presented. This method allows the full size of the regions of activation to be estimated and also provides information on the region substructure. Results are presented in conjunction with Time of Flight cerebrovascular data, showing the relationship between arterial dilation, viscoelastic changes, and region substructure. This method has excellent potential to expand our understanding of mechanical and structural changes in the active brain. |
| 3968 | Computer 114
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Magnetic resonance shear wave elastography using transient acoustic radiation force excitations and sinusoidal displacement encoding |
1Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Siemens Healthcare, Salt Lake City, UT, United States |
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A novel elastography approach that uses sinusoidal motion encoding gradients to encode the displacement time-history following a single transient acoustic radiation force excitation is presented. This technique may be particularly well suited for performing elastography before, during, and after MR-guided focused ultrasound treatments since the same device used for therapy is used as an excitation source for elastography. |
| 3969 | Computer 115
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Partial Vibration MR Elastography: Zero-MR phase image MRE |
1Radiological Sciences, Tokyo Metropolitan University, Tokyo, Japan, 2National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan, 3Office of Radiation Technology, Keio University Hospital, Tokyo, Japan, 4Tokyo Denki University, Tokyo, Japan |
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We developed a new technique for MR elastography (MRE) without using MR phase images (Zero-MR phase image MRE). A general MRE uses MR phase images as a wave image. Proposed technique was used MR magnitude images instead of MR phase images as a wave image by using the partial vibration. Proposed technique (partial vibration MRE technique) performance was comparable to that of a continuous vibration (conventional) MRE. Since partial vibration MRE need an only few second vibration, it could dramatically eliminated the patients' vibration-related discomfort. |
| 3970 | Computer 116
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Effect of breath hold mode on the storage modulus of the liver in healthy individuals studied with a gravitational transducer at magnetic resonance elastography |
1Center for Research on Inflammation, Inserm UMR1149, Paris, France, 2Radiology department, Beaujon hospital, AP-HP, Clichy, France, 3King's College London, London, United Kingdom, 4LVTS, Inserm U1149, Paris, France |
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Although MR elastography (MRE) is a preferred diagnostic tool for hepatic fibrosis, MRE-derived mechanical properties are affected by factors such as portal pressure. Since portal pressure is modulated across the breathing cycle, we sought to evaluate the effect of breathing condition by acquiring MRE in end expiration and end inspiration in 19 healthy volunteers. A gravitational transducer operating at 50Hz was used, which yielded a satisfactory repeatability. Storage modulus values were significantly higher at end inspiration than at end expiration, and the amplitude of the difference was significantly correlated to the end inspiration storage modulus values. |
| 3971 | Computer 117
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Fast Brain MR Elastography Using a Simultaneous Multislice EPI Acquisition on a Compact 3T Scanner |
1Radiology, Mayo Clinic, Rochester, MN, United States |
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In this study, we developed a fast MR elastography (MRE) pulse sequence using a simultaneous multislice (SMS)-EPI acquisition. The feasibility of SMS-EPI-MRE was demonstrated on a compact 3T scanner in a pilot volunteer study using 2 different head-coil arrays. Our results show that the overall scan time for 60-Hz 3-mm isotropic and 80-Hz 2-mm isotropic whole-brain MRE acquisitions were greatly reduced to 1-2 minutes (depending on the multiband acceleration) and 3:21 minutes, respectively. The wave images and stiffness maps from the SMS acquisitions were comparable to conventional MRE results. |
| 3972 | Computer 118
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Repeatability and Clinical Performance of Non-gated, Free-breathing, MR Elastography (MRE) of the Liver |
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Gastroenterology, Mayo Clinic, Rochester, MN, United States |
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While conventional MRE is easily performed during suspended respiration, a free breathing MRE technique would be advantageous in pediatric and other patients. We assessed the repeatability of free-breathing MRE in comparison to conventional breath held acquisitions in volunteers and the clinical performance of free-breathing MRE in a cohort of 56 patients with chronic liver diseases. Results demonstrated comparable repeatability and excellent agreement of the averaged liver stiffnesses measured using the two techniques. In summary, free-breathing MRE provides highly repeatable and accurate liver stiffness values. |
| 3973 | Computer 119
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Quantitative Effects of Geometric Distortion On Brain Mechanical Property Estimation In Magnetic Resonance Elastography |
1Biomedical Engineerng, University of Delaware, Newark, DE, United States, 2Thayer School of Engineering, Dartmouth College, Hanover, NH, United States, 3Biomedical Engineering, University of Delaware, Newark, DE, United States |
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Geometric distortion in MRI arises from magnetic field-inhomogeneity and susceptibility differences at air/tissue/bone interfaces, and this distortion is greater at long readout times used in high-resolution imaging. Distortion may particularly impact magnetic resonance elastography (MRE), which calculates brain mechanical properties by imaging shear wave displacements then solving applying a nonlinear inversion algorithm. In this study, we systematically examine effects of distortion and correction algorithms on MRE data through a series of simulations and in vivo experiments, and find that geometric distortion limits the quantitative accuracy of brain MRE. |
| 3974 | Computer 120
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Low-Rank Denoising of Magnetic Resonance Elastography Images |
1Biomedical Engineering, University of Delaware, Newark, DE, United States, 2Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Thayer School of Engineering, Dartmouth College, Hanover, NH, United States |
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Magnetic resonance elastography (MRE) is a phase contrast-based MRI technology that can create whole brain mechanical property maps in vivo. MRE involves the solution of an inverse problem to estimate mechanical properties. Data noise degrades the accuracy of the recovered property images (elastograms). Most MRE acquisitions aim to achieve signal-to-noise ratio (SNR) above a certain threshold, though low SNR is a common issue. We propose a new method to denoise MRE data through spatiotemporal modeling. By approximating MRE data as low-rank, large improvements in SNR can be achieved, which can lead to the ability to salvage MRE data that otherwise would be unusable. |
| 3975 | Computer 121
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Multi-frequency magnetic resonance elastography with spiral readout, respiratory navigator and stroboscopic wave sampling for cardiac stiffness mapping with high spatial and temporal resolution. |
1Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 2Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany |
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Cardiac magnetic resonance elastography (MRE) promises a quantitative mapping of the mechanical function of the myocardium. However, the implementation of cardiac MRE is challenging due to fast motion, high heterogeneity and temporally varying intrinsic properties of the heart. To overcome these limitations, we introduce a novel cardiac MRE sequence with spiral readout, respiratory navigator and stroboscopic wave sampling. It allows acquiring 100 wave fields with 45ms temporal resolution, 1.6x1.6mm² in-plane resolution at three frequencies within 9 minutes. Preliminary data in 8 healthy volunteers show a substantial variation of myocardial shear-wave velocity from 1.5±0.2m/s during diastole to 2.1±0.2m/s during systole. |
| 3976 | Computer 122
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Correcting portal-venous partial-volume effects in dynamic contrast-enhanced MRI of the liver |
1Biomedical Imaging Science Department, University of Leeds, Leeds, United Kingdom, 2Leeds Teaching Hospitals NHS Trust, St James University Hospital, Leeds, United Kingdom |
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We investigated the effect of partial-volume corrections on the liver perfusion and function measured from DCE-MRI data using dual input two compartment uptake model. Following the convection principle in the human body, partial-volume error for hepatic portal vein is determined by taking the ratio of time integrals of venous and arterial input function. We found moderate correlation between the corrected and uncorrected venous plasma flow and a poor correlation between corrected and uncorrected extracellular volume and uptake rate. This indicates that partial-volume effect is significant and should be corrected for in the determination of perfusion and liver function. |
| 3977 | Computer 123
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Magneto-Caloric Materials as Symmetric Reverse-Contrast Switchable MRI Labels |
1Applied Physics and Instrumentation Group, HHMI-Janelia Reseach Campus, Ashburn, VA, United States, 2Electrical and Computer Engineering Department, United States Naval Academy, Annapolis, MD, United States, 3Laboratory of Functional and Molecular Imaging, NIH/NINDS, Bethesda, MD, United States, 4NIH Mouse Imaging Facility, NIH/NINDS, Bethesda, MD, United States |
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We describe the use of magneto-caloric materials as symmetric reverse-contrast switchable MRI labels at physiological temperatures. We present physical and temperature tunable MRI measurements on two different magneto-caloric materials, Iron-Rhodium (Fe-Rh) and Lanthanum-Iron-Silicon (La-Fe-Si) that both have sharp first-order magnetic phase transitions at the same bias DC magnetic field of 1 Tesla and physiological temperature of 37°C (310K), but with simultaneously positive and negative slope of magnetization vs. temperature, respectively, and therefore reverse image contrast in MRI. Thus, we show that different magneto-caloric materials provide an opportunity for the development of versatile multi-functional high differential contrast ratio switchable MRI labels. |
| 3978 | Computer 124
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Labyrinthine lymph MR imaging of patients with vertigo disease: an imaging comparison study with intratympanic or intravenous gadolinium injection |
1Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China, 2GE Healthcare, MR Research China, Beijing, China, 3Gong Ruozhen Innovation Studio, Shandong Medical Imaging Research Institute Affiliated to Shandong University, Shandong, China, 4Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China |
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In this study, we aimed to determine whether intratympanic (IT) or intravenous (IV) injection of gadolinium is more suitable for labyrinthine lymph imaging of patients with vertigo disease. The corresponding MR images with IV and IT injection were thus systematically compared. While comparable detection of endolymphatic hydrops were shown using both injection methods, higher image contrast between affected and unaffected sides of perilymph region were found using IV method than using IT method. We therefore, demonstrated that IV method can be further applied in clinical diagnosis for patients with vertigo disease. |
| 3979 | Computer 125
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Effects of Multiple Contrast Agents in Multi-Modality Imaging for Liver Embolizations: A Preliminary MR Analysis |
1Medical Physics, University of Wisconsin Madison, Madison, WI, United States, 2Radiology, University of Wisconsin Madison, Madison, WI, United States |
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Transarterial embolization (TAE) is a standard treatment for liver tumors and results in stasis and an accumulation of iodinated contrast agent in the liver. This study demonstrated that when iodinated contrast agents are present in MR, a T1 and T2 shortening effect can occur. We completed a preliminary analysis investigating pre- and post-TAE MR signal changes in the presence of iodine and gadolinium based contrast agents in-vivo (pilot swine study) and in phantoms. Understanding variations in MR images caused by contrast agents used for other modalities could help reduce errors in multimodality imaging studies. |
| 3980 | Computer 126
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Quantitative Magnetization Transfer: A Comparison of State-of-the-Art Acquisitions |
1Wellcome Centre for Integrative Neuroimaging, FMRIB, University of Oxford, Oxford, United Kingdom |
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As development of quantitative magnetization transfer (qMT) has progressed, different sequences have been developed and independently optimised. Here, we present a comparison of the three main qMT acquisition sequences: spoiled gradient echo (SPGR), selective inversion recovery with fast spin echo (SIR-FSE) and balanced steady-state free precession (bSSFP). A novel comparison is accomplished by optimising each protocol using Cramér-Rao lower bounds (CRLB) theory. Our results indicate that SPGR qMT may introduce additional uncertainty due to the low sensitivity surrounding T2f, while bSSFP may provide a robust alternative for efficient 3D acquisitions. |
| 3981 | Computer 127
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Optimizing Neuromelanin-sensitive Turbo Spin Echo sequences using the extended phase graph formalism including magnetization transfer effects |
1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico - Universidade de Lisboa, Lisbon, Portugal, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 3Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom |
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Neuromelanin(NM)-sensitive imaging detects contrast differences due to magnetization transfer (MT) effects. We aimed to evaluate the value of adding preparation inversion pulses (IR) to multi-slice turbo spin echo (MS-TSE) sequences, using the recently introduced extended phase graphs with MT effects framework. Simulation results were in agreement with experimental phantom data. The MT contrast could be increased using IR MS-TSE sequences and these results were confirmed in vivo, with improved detectability of the substantia nigra. The next step will be to test the use of this type of sequences in the clinic, finding the optimal tradeoff between contrast and signal-to-noise ratio. |
| 3982 | Computer 128
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Neural network for fast quantitative magnetization transfer imaging |
1Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of, 2Seoul National University Hospital, Seoul, Korea, Republic of |
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Quantitative magnetization transfer ( |
| 3983 | Computer 129
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Estimation of Semi-solid Saturation in Brain White Matter after Composite MT Pulses by Means of Bloch Simulation |
1AMRI, LFMI, NINDS, NIH, Bethesda, MD, United States |
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The magnetization level of macromolecular protons (MPs) affects that of water protons through magnetization transfer, a phenomenon that represents a confounding factor in quantitative MRI. Here we investigated whether MP spectral lineshape can be sufficiently accurately modelled by a single Lorentzian, which would facilitate estimating MP magnetization and saturation levels from Bloch simulations and a 2-pool MT model. We compared simulated effects of 10 different composite MT pulses and experimental results from 11 healthy volunteers at 7T. Results demonstrate a good fitting to the observed water signal evolution. Deviation of the simulated initial MP saturation from calculated levels was observed, indicating potentially unaccounted factors such as inhomogeneous MT effects. |
| 3984 | Computer 130
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Bayesian fitting of Chemical Exchange Saturation Transfer (CEST) imaging data with an analytical model for multiple CEST pools |
1Brain Repair and Rehabilitation, University College London, London, United Kingdom, 2Max-Planck institute for biological cybernetics, Tübingen, Germany |
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A Bayesian fitting algorithm was combined with an analytical solution of the Bloch-McConnell equations for multiple CEST pools. The performance of the suggested fitting approach was evaluated in simulated and phantom experiments. Specifically, the application to Taurine-Creatine solutions which exhibit overlapping resonance peaks in the Z-spectrum was investigated. Although the analytical solution introduced biases into the estimated parameters, the estimated exchange rates correlated with the pH of the solutions. Hence, this approach can be applied to detect pH differences based on exchange rate estimates in the case of overlapping resonance peaks in the Z-spectrum. |
| 3985 | Computer 131
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Parallel Transmission Based Alternating Saturation Pulse Design for CEST Imaging |
1Radiology, Vanderbilt University, Nashville, TN, United States, 2Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 3Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States |
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A novel saturation pulse design method for ultra-high field human CEST imaging is presented. By alternating complementary saturation patterns using parallel transmission, the method achieves homogeneous CEST saturation in the whole brain volume. |
| 3986 | Computer 132
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GlucoCEST MRI detects metabolic degradation in the mouse brain after rapid microwave fixation |
1Howard University, Washington, DC, United States, 2Children's National Medical Center, Washington, DC, United States, 3Fu Jen Catholic University, New Taipei City, Taiwan, 4Yuan Ze University, Taoyuan City, Taiwan |
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The study of neurometabolites and the detection of glucose in the brain has relied on anesthetized animals. Prolonged periods of anesthesia required for these studies may affect these metabolites and the ability to interpret glucose detection in the brain. However, performing post-mortem studies of neurometabolites and glucose detection in the brain is difficult to interpret because of rapid degradation. In this study, we utilized focal beam microwave irradiation (FBMI) without anesthesia to collect brain tissue and determine whether there is postmortem degradation of neurometabolites and glucose using 1H-NMR and glucoCEST. |
| 3987 | Computer 133
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A custom-designed 1H saddle coil for CEST imaging at 14.1 Tesla |
1Laboratory for functional and metabolic imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2School of Health Sciences, University of Applied Sciences and Arts of Western Switzerland (HES-SO), Geneva, Switzerland, 3Department of Psychiatry, McGill University, Montreal, QC, Canada, 4Department of Radiology, Université de Lausanne (UNIL), Lausanne, Switzerland, 5Department of Radiology, Geneva University Hospital (UNIGE), Geneva, Switzerland |
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We propose an alternative RF method for small animal CEST imaging at ultra-high magnetic field by using a 1H saddle coil instead of a quadrature birdcage coil. The coils create similar homogeneous B1 maps with an 2.2x increase of SNR for the saddle coil. Both coils show a similar degree of precision when tested for in vitro glycoCEST imaging. In rodent skeletal muscle the saddle coil offers a good performance with respect to the sensitivity for glycoCEST imaging. |
| 3988 | Computer 134
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Towards glycoCEST in the liver at 7T with a multi-transmit system |
1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Imaging Division, University Medical Centre Utrecht, Utrecht, Netherlands |
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The purpose of this work was to optimize and evaluate different parameters of the CEST acquisition protocol at 7 Tesla to be able to detect the glycoCEST signal in the human liver. The so far optimized parameters were determined as 65 frequency offsets, 60 saturation pulses of 25 ms duration and an effective B1 of 1.5uT. As conclusion, we have demonstrated that in-vivo liver glycoCEST can be detected in the human liver by using a CEST acquisition at 7T. The parameters can be further optimized to obtain a stronger glycoCEST effect. |
| 3989 | Computer 135
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Imaging of hydrogel biomaterials with Magnetization Transfer MRI |
1University Medical Center Utrecht, Utrecht, Netherlands, 2Eindhoven University of Technology, Eindhoven, Netherlands |
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We developed and validated MT-MRI protocols for imaging of hydrogel biomaterials and their pH-switchable behavior. Given that all hydrogels are expected to have an MT effect, the proposed MT-MRI protocols may be applicable for imaging of other hydrogel biomaterials as well. |
| 3990 | Computer 136
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Tuning the ratio of exchangeable protons in iodinated agents to improve the accuracy and detection range of pH mapping under a single low power saturation |
1School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, GuangZhou, China, 2Philips Healthcare, GuangZhou, China |
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Ratiometric chemical exchange saturation transfer MRI (acidoCEST) using two distinct exchangeable protons in iodinated agents has been widely developed for in vitro and in vivo pH mapping. The accuracy of acidoCEST and pH detection range greatly relies on the applied B1 saturation pulse and chemical properties of labile protons. In this study we try to make full use of different chemical property of two labile protons. Through finely adjusting their ratio, the accuracy and pH detection range under a single low-power B1 saturation has shown to be improved |
| 3991 | Computer 137
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Thermal sensitive pH imaging using CEST |
1Tokushima University, Tokushima, Japan, 2Kanazawa University, Kanazawa, Japan, 3Global MR Applications and Workflow, GE Healthcare Japan, Tokyo, Japan |
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We performed phantom study with CEST and clarified pH change depending on temperature. Linear regression analysis shows a strong significant correlation between temperature and MTRasym at 2.0 ppm in all egg white albumin samples (R2 > 0.78, P < 0.05). As pH changed with temperature, we found that the offset frequency of MTRasym was more sensitive at 2.0 ppm than that at 3.5 ppm. |
| 3992 | Computer 138
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Comparison of Different CEST Metrics for Brain Tumor Grading with Semi-Automatic ROIs |
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, China, 3Department of Radiology, Johns Hopkins University, Baltimore, MD, United States |
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The performance of three CEST metrics including |
| 3993 | Computer 139
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GagCEST of human intervertebral lumbar discs compared to 23Na MRI at 7 Tesla |
1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Clinical Division for Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria, 3CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria |
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Six healthy volunteers were measured to assess the feasibility and differences of 23Na-MRI and gagCEST in human intervertebral lumbar discs at 7T. MTRasym values from GagCEST data have shown to have similar potential as normalized 23Na-MRI, but were acquired in half the time and without the need for special hardware. |
| 3994 | Computer 140
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Data-Driven Spectral Feature Extraction in 9.4T CEST MRI data of the human brain |
1High-field magnetic resonance center, Max Planck Institute for biological cybernetics, Tübingen, Germany |
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Model-based extraction of features, e.g. Lorentzian fitting of Z-spectra, in CEST MRI can be limited by the underlying model assumptions. Here we analyzed high spectral resolution Z-spectra acquired at 9.4T in five healthy subjects and one tumor patient using principal component analysis, a purely data-driven statistical procedure. Projection of Z-spectra onto principle components from a group of healthy subjects provides several relevant contrasts which reveal anatomical detail and correlate with Gadolinium uptake signatures in a brain tumor patient. |
| 3995 | Computer 141
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Development of whole-brain 3D snapshot CEST MRI at 3T |
1High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Department of Biomedical Magnetic Resonance, Eberhard-Karls University Tuebingen, Tuebingen, Germany |
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In its application Chemical exchange saturation transfer (CEST) suffers from the drawback of long acquisition times. To approach this issue we demonstrate the feasibility of a 3D gradient echo based CEST sequence for 3T that provides whole brain (WB) coverage without additional measurement time. In addition, the suggested post processing helps to improve the determination of the CEST effects from the WB data. CEST contrasts derived from the presented method are of equal quality as those of commonly used methods. |
| 3996 | Computer 142
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Feasibility of Partial 3D GluCEST in Healthy Human Adults at 7.0T |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Psychiatry, University of Colorado, Aurora, CO, United States |
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GluCEST imaging at 7.0T has been promising in clinical applications as demonstrated in small subset of temporal lobe epilepsy subjects and in early psychosis. However, these studies employed 2D GluCEST limiting to single slice and limited coverage of anatomy of interest. Here, we tried to implement the partial 3D GluCEST in order to capture the glutamate contrast from the entire hippocampus as opposed to single slice in the same amount of time. |
| 3997 | Computer 143
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Pulsed Saturation Transfer in Glioblastoma at 1.5T |
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada, 4Medical Biophysics, University of Toronto, Toronto, ON, Canada, 5Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland |
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The purpose of this study was to quantify the effects of saturation transfer (CEST and MT) measurements in glioblastoma (GBM) patients at 1.5T. Data from GBM patients (n=10), treated with intensity modulated radiation therapy with a dose of 2 Gy per session with concurrent temozolomide, were analyzed before and after 10 treatment fractions. MT data were fitted to the Bloch-McConnell (BM) equations using a two-pool model with extended phase graphs (EPG) incorporated into the model. Results showed differences between normal and tumor regions and demonstrated promise for the application of CEST at 1.5T. |
| 3998 | Computer 144
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Measuring the pH of human blood using CEST |
1University of Nottingham, Nottingham, United Kingdom, 2University Medical Center Utrecht, Utrecht, Netherlands |
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Iopamidol has been previously used as a CEST based contrast agent to measure pH in mouse kidneys. Here we aim to move this work towards clinical translation by calibrating the pH of ex vivo human blood to the ratiometric values calculated from the two Iopamidol CEST peaks. This is performed in the physiological range for human blood, between pH 6.8 and 8.4. |
| 3999 | Computer 145
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Measuring the water exchange rate for various pools in the z-spectrum of the human brain |
1University of Nottingham, Nottingham, United Kingdom, 2University Medical Center Utrecht, Utrecht, Netherlands |
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True quantification of MT, CEST and NOE pools is difficult to achieve, as the exchanging pool size and exchange rate cannot be readily separated. Here we use a Particle Swarm Optimisation algorithm to solve this problem, which we show to be capable of quantifying pool size, exchange rate, and apparent T2s of exchanging pools without the need for initial guesses. We apply this to z-spectra acquired in vivo from the human brain, and quantify the exchanging pools in grey and white matter. |
| 4000 | Computer 146
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Initial CEST study in a microcavity array based 3D cell culture system |
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, 2Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany |
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Chemical exchange saturation transfer (CEST) is a powerful method for the investigation of biomolecules. An MR-compatible bioreactor, on the other hand, creates a well-controlled environment for human cells. The combination of both methods should make it possible to extract cellular signals from the bioreactor. Therefore, we investigated the possibility of performing CEST measurements in an actively-perfused bioreactor with HepG2 cells. We could show that perfusion had no effect on the CEST signals and that the main signals originated from the cells. However, the sub-optimal shim condition in the bioreactor led to a reduction in CEST signals. |
| 4001 | Computer 147
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Producing a Synthetic Magnetization Transfer Reference Volume with T1 Maps Acquired using a Different Pulse Sequence: Practical Considerations. |
1Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada, 2Psychiatry, University of Toronto, Toronto, ON, Canada |
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Macromolecular proton fraction (MPF) mapping can be achieved using only two acquired volumes, one with and one without a magnetization transfer (MT) pulse, in addition to T1, B1 and B0 maps. Further scan time reduction is possible if the T1 and B1 maps required for MPF computations are used to generate a synthetic reference image, eliminating the reference image acquisition. This has been shown to work when the images used to generate T1 were acquired from the same sequence and parameters as the MT. We investigate if we can use a different sequence with a calibration to achieve this. |
| 4002 | Computer 148
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Positive Contrast Chemical Exchange Imaging using RACETE |
1Comprehensive Heart Failure Center, University Hospital Wuerzburg, Wuerzburg, Germany, 2Experimental Physics 5, University Wuerzburg, Wuerzburg, Germany |
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The RACETE sequence is a novel method for imaging chemical exchange. As it refocuses the magnetization transferred while stored in the longitudinal state, it yields a positive contrast. By creating a refocused sequence other properties of standard MR sequences, such as excitation pulse phase variation, can be exploited. |
| 4003 | Computer 149
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Microfluidics preparation of liposome containing alginate hydrogel microbeads for CEST MRI |
1City University of Hong Kong, Hong Kong, China |
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Image-guided cell therapy plays an important role in monitoring and adjusting the treatment regimen. We have demonstrated that cell viability could be monitored by CEST pH-nanosensors in alginate hydrogel microbeads. Here, we investigated the use of microfluidics to generate liposome containing microbeads and examined their CEST properties after loading with the iodine CT contrast agents Iohexol and Iopamiro. We have successfully demonstrated that the microbead size has greatly reduced from 300-400 μm to 20 μm. Moreover, iodine agents loaded liposomal microbeads generated 4% CEST contrast at 4.2 ppm at 3T. These findings demonstrate a robust platform for the fabrication of liposome containing microbeads under CEST MR guidance. |
| 4004 | Computer 150
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Extended phase graph framework for "inhomogeneous" MT systems. |
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom |
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Recently, the extended phase graph with exchange (EPG-X) formalism has been introduced for modelling magnetization transfer (MT) effects during arbitrary pulse sequences. Here, we present a further extension to include a dipolar order component of the macromolecular (i.e. semisolid) pool, as has been proposed to understand the “inhomogeneous” MT (ihMT) contrast mechanism observed in ordered structures such as myelin and muscle. Preliminary results demonstrate the flexibility of the developed simulation tool for ihMT contrast optimisation and the investigation of steady-state sequence dynamics. |
| 4005 | Computer 151
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Eliminating chemical shift artefact using simultaneous, separate water and fat excitation combined with CAIPIRINHA |
1Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria |
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Imaging of many body regions is adversely affected by the chemical shift between fat and water. We propose a new method for simultaneous, separate imaging of fat and water in which multiband pulses are used to simultaneously excite fat and water at their characteristic resonance frequencies, and CAIPIRINHA in combination with parallel imaging to reconstruct separate images of the two species. The fat image is corrected for chemical shift displacement and either recombined with the water image or evaluated separately. The proposed method achieves reliable water-fat separation and complete elimination of the chemical shift artefact in musculo-skeletal and breast imaging. |
| 4006 | Computer 152
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Fat quantification using simultaneous, separate water and fat excitation combined with CAIPIRINHA |
1Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Institute of Scientific Instruments of the CAS, Brno, Czech Republic, 4Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 5Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 6Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria |
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Fat quantification by MRI plays an important role in assessing hepatic steatosis and bone marrow changes. We propose a new method for fat quantification in which multiband pulses are used to separately but simultaneously excite fat and water. CAIPIRINHA encoding allows overlapping images of the two species to be separated. Fat fraction maps can be calculated from fat and water images with appropriate consideration of relaxation times. The proposed method is validated on phantoms with different fat concentrations, where it yields similar fat fraction values to the Dixon approach and single-voxel spectroscopy. |
| 4007 | Computer 153
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Accelerated Single-Min-Cut Graph-Cut Algorithm Using a Variable-Layer Graph Construction Improves Field-Mapping in Water–Fat Regions |
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany, 2Munich School of Bioengineering, Technical University of Munich, Munich, Germany |
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Accurate field-mapping is critical in body imaging for both robust water–fat separation and accurate quantitative susceptibility mapping. The present work proposes a single-min-cut field-mapping method to improve field-map results in water–fat regions. The proposed method based on a variable layer graph construction, solves the phase-wrapping problem and yields directly into non-wrapped field-maps. In challenging areas with low SNR or strongly varying field-maps the accuracy is significantly increased, while the computational cost is drastically reduced. |
| 4008 | Computer 154
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Separation of Water and Fat during Spin-Lock Magnetic Resonance Imaging with Multifrequency Fat Spectrum Modeling |
1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, Hong Kong, 2Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany, 3Shenzhen Institutes of Advanced Technology, Shenzhen, China |
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Spin-lock technologies are useful for probing macromolecular environment of tissue. The conventional spin-lock approaches cannot lock water and fat spins simultaneously due to chemical shift effect of fat, which can lead to artifacts in tissues with fatty infiltration. Based on the latest development of the spin-lock technique, we propose spin-lock Dixon methods to perform water-fat separation in spin-lock MRI. Our methods may offer a solution to perform reliable spin-lock MRI in tissues with fatty infiltration. |
| 4009 | Computer 155
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Transition region extraction algorithm for Two Point Dixon Imaging |
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences, Shenzhen, China, 2Huazhong University of Science and Technology, Wuhan, China, 3University of Chinese Academy of Sciences, Beijing, China |
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Purpose: To propose a transition region extraction algorithm for two point fat-water separation. Methods:In the proposed method, fat-water transition region is first extracted as initial information. Remaining pixels are determined based on transition region in units of sub-region instead of pixels to improve calculation efficiency and avoid the vulnerability to the growing path. Results:Fat-water separation were successfully achieved by the proposed method in the datasets tested. Conclusion: A method based on fat-water transition region extraction is proposed for two point fat-water separation. |
| 4010 | Computer 156
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B1 and B0 Insensitive Uniform Fat-saturation for Joint Imaging |
1Siemens Healthineers, Rochester, MN, United States, 2Siemens Healthineers, Berkeley, CA, United States, 3Siemens Healthineers, Los Angeles, CA, United States, 4Siemens Healthineers, Portland, OR, United States, 5Siemens Healthineers, Austin, TX, United States |
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In this work we propose B1 and B0 insensitive, uniform, and robust fat suppression for joint imaging using dual repetition spectrally selective high bandwidth Shinnar–Le Roux RF pulses. The optimal flip angle combinations for B1 insensitivity were calculated using Bloch simulations. Efficacy of the novel fat-sat mechanism in achieving B1 robust uniform fat-sat was demonstrated in the knee at 3T. |
| 4011 | Computer 157
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Sub-voxel Estimation of Fat Infiltration in Degenerative Muscle Disorders using Multi-T2 Analysis – a Quantitative Disease Biomarker |
1Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel, 2CNRS, CRMBM, Aix Marseille University, Marseille, France, 3Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel, 4Center for Advanced Imaging Innovation and Research (CAI2R), New-York University Langone Medical Center, New York, NY, United States |
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T2 relaxation is an effective biomarker for muscle pathologies including inflammation, necrosis, or fatty infiltration. Accurate quantification of T2 values is hampered due to the inherent bias of fast multi-echo spin-echo (MESE) protocols by stimulated echoes. The echo-modulation curve (EMC) algorithm overcomes this problem and provides accurate T2 values which are stable across scanners and scan-settings. In this work, we present an extension of the EMC algorithm for T2-based fat/water quantification, alongside two new quantitative biomarkers of |
| 4012 | Computer 158
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Robust Chemical Exchange Spin-lock performed using adiabatic pulse with Toggling Inversion Preparation at 3.0T |
1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 2Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States |
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The measurement of R1rho (1/T1rho) spectrum and its asymmetry have several advantages over Chemical Exchange Saturation Transfer (CEST) to probe chemical exchange effect. However, these approaches suffer from B1 Radiofrequency (RF) and B0 field inhomogeneities. In this work, we proposed a new approach to perform robust R1rho asymmetry measurement using adiabatic spin-lock RF pulse and demonstrated its potential to probe metabolites. |
| 4013 | Computer 159
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Relaxation-compensated APT and rNOE CEST-MRI of human brain tumors at 3 T |
1Divsion of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Department of High-field Magnetic Resonance, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany, 3Molecular Structure Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany |
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In this study, the established acquisition protocol for relaxation-compensated APT and rNOE CEST-MRI at 7 T has been successfully transferred to a clinically relevant magnetic field strength of 3 T. This opens up the door to clinical trials with a large number of participants, thus enabling a comprehensive assessment of the clinical relevance of relaxation-compensation in CEST-MRI. The presented CEST sequence is currently part of the clinical routine acquisition protocol for brain tumor patients at our institute. |
| 4014 | Computer 160
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Deep Neural Network for Single-Point Dixon Imaging with Flexible Echo Time |
1Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 3Department of Diagnostic Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States |
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Dixon imaging generally requires multiple input images acquired at varying echo-times for robust phase-correction and water and fat separation. However, multi-echo Dixon imaging suffers from relatively long scan-time and is more susceptible to motion related artefacts and inflexible in choosing scan-parameters. Recently, it was reported that deep neural networks can help separate water and fat from two-point, or multi-point Dixon images. In this work, we present a deep learning based method that can achieve water and fat separation from a single image acquired at a flexible echo-time and therefore can help alleviate the limitations of multi-point Dixon imaging. |
| 4015 | Computer 161
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Detecting the presence of fat using PLANET-based parameter mapping |
1Center for Image Sciences, Imaging Division, UMC Utrecht, Utrecht, Netherlands, 2Department of Radiotherapy, Imaging Devision, UMC Utrecht, Utrecht, Netherlands |
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The PLANET method was introduced to simultaneously map T1, T2, banding free magnitude, local off-resonance, and RF phase using phase-cycled bSSFP data. All these parameters are estimated from a linear least squares fitting of an ellipse to complex data. The PLANET method is based on a Lorentzian single-component relaxation model, which results in symmetric bSSFP magnitude profile and elliptical behavior of the complex transverse magnetization. However, when a second or more components with different frequency distributions are present within a voxel, the complex signal might not lie on an ellipse anymore. Hence, PLANET post-processing would return erroneous quantitative parameters. In this study we show that the sensitivity of PLANET to the presence of multiple components can be exploited to map the spatial distribution of voxels in which multiple spectral peaks are present. We demonstrate that this feature of PLANET can be used to create fat-only map. |
| 4016 | Computer 162
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deepCEST: 9.4 T spectral super resolution from 3 T CEST MRI data - optimization of network architectures |
1High-field magnetic resonance center, Max Planck Institute for biological cybernetics, Tübingen, Germany, 2Diagnostic & Interventional Neuroradiology, University Clinic Tuebingen, Tübingen, Germany |
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Different neural network architectures for predicting 9T CEST contrasts from 3T spectral data are investigated as well as the influence of different training data sets on the quality of resulting predictions. Although optimized convolutional neural network (CNN) architectures perform well, the best results were reached with a simpler feedforward neural network (FFNN). As CNNs have many hyperparameters to tune, this work forms a basis for CNN architecture optimization for the proposed super-resolution CEST application. |
| 4017 | Computer 163
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A Potentially New Class of Redox-Sensitive CEST Agents: Preliminary Thiol-CEST Studies with Glutathione and Cysteine |
1School of Science and Health, Western Sydney University, Sydney, Australia, 2Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States |
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In this study, we show that thiol-water proton exchange can generate MRI contrast by performing proton chemical exchange saturation transfer (1H-CEST) experiments on glutathione (GSH) and cysteine (Cys). The thiol proton exchange was quantified at various pHs, with Cys thiol exhibiting faster and more base-catalyzed exchange than GSH. However, both GSH and Cys thiol exchange were too fast to generate contrast at physiological pH. Potential applications of thiol compounds as redox-sensitive CEST agents are suggested. |
| 4018 | Computer 164
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Characterization of B1 calibration curves with respect to durations for myo-Inositol CEST ( MICEST) in the healthy human brain at 7.0T |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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myo-Inositol (MI) is one of the important brain metabolites. In the recent years, MICEST technique has emerged as a neuroimaging biomarker and its application was shown in an Alzhemer’s mouse model. In this study, we tried to explore and evaluate the behavior of MICEST at different saturation parameters in healthy human volunteers at 7.0T with an aim to understand and set optimal saturation parameters for the human studies. |
| 4019 | Computer 165
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Optimized B1/B0 correction for whole-brain CEST imaging using 3D-EPI at 7T |
1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, 2Max-Planck Institute for Biological Cybernetics, Tübingen, Germany, 3Department of Physics and Astronomy, University of Bonn, Bonn, Germany |
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Compared to conventional single-slice or small volume measurements, whole-brain CEST acquisitions present new challenges, in particular at ultra high-field (UHF). In a first step to account for the broader B1 variation, we analyzed the distribution of reference voltages in the brain of nine subjects. Based on these results, we repeated a whole-brain CEST experiment with seven different reference voltages to optimize the correction for B1 inhomogeneities in the CEST contrast maps. Additionally, we extended the saturation-offset list to compensate for the higher variation of the static magnetic field for whole-brain experiments compared to examinations with smaller FOVs. |
| 4020 | Computer 166
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Validation of a tool for body fat and skeletal muscle quantification using MRI and application in the assessment of body composition in patients with colorectal and lung cancer |
1Centre for Medical Imaging, University College London, London, United Kingdom |
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Body composition analysis holds considerable promise in clinical prognostication. For example, sarcopenia (particularly sarcopenic obesity) is associated with poor outcomes in cancer patients. To date, most clinical studies using body composition analysis have used data derived from volumetric CT; however, whole-body MRI (WB-MRI) is increasingly used in cancer staging and analysis of these MRI data could be an alternative means to calculate body composition. In this study, we describe and validate a simple, practical tool for quantification of body fat and skeletal muscle from WB-MRI and demonstrate its application to two cohorts of patients with lung and colon cancer. |
| 4021 | Computer 167
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An Automated Approach for the Optimised Estimation of Breast Density with Dixon Methods |
1CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden Foundation Trust, London, United Kingdom, Sutton, United Kingdom, 2The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom, 3St George's University Hospitals NHS Foundation Trust, London, United Kingdom |
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In Breast MRI, Dixon fat-water separation techniques have been invaluable for the measurement of breast-density in studies of breast cancer risk. A fundamental source of error in Dixon methods arises from differences in the signal intensity from water and fat, associated with differences in proton density and relaxation times. We propose an automated method to introduce a scaling factor that minimizes these errors. We demonstrate our method in a group of 14 subjects, imaged at 3T with different levels of T1-weighting. |
| 4022 | Computer 168
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Thermal measurement in fatty tissues with Z-Spectrum Imaging |
1Radiology, University of Illinois at Chicago, Chicago, IL, United States, 2Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 3Radiology, Tongji Medical College, Wuhan, China, 4Research Resources Center, University of Illinois at Chicago, Chicago, IL, United States, 5Biophysics and Biophysiology, University of Illinois at Chicago, Chicago, IL, United States |
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Z-spectrum imaging (ZSI) has been recently introduced as a method to quantify fat-water fraction based on the direct saturation of both water and fat. Here we demonstrate that ZSI can also assess temperature in fatty tissues, by measuring the relative fat-water chemical shift (FWCS) change due to the shift of water resonance at increased temperature. The protocol was tested on a whipped cream phantom and showed FWCS changing linearly with temperature. The protocol was also tested on healthy mice and subjects, paving the way for the study of fat metabolism, in particular of brown adipose tissue. |
| 4023 | Computer 169
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A quantitative tool for the speciation of mineralized iron in the brain |
1C. J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, 2Leiden University, Leiden, Netherlands, 3Human Genetics, Leiden University Medical Center, Leiden, Netherlands |
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We implemented and optimized an Off-Resonance Saturation (ORS) pulse sequence on a 7T- preclinical scanner, with the aim of quantifying iron present in brain phantoms doped with ferritin-bound and magnetite-bound iron. These mineralized iron forms are known to be involved in ageing, and also in toxic cellular pathways in neurodegenerative diseases. We show that the ORS method offers the possibility to quantify, and possibly differentiate, iron ions in brains affected by neurodegenerative diseases which are characterized by disturbed iron homeostasis. Additionally, our results are discussed in the light of susceptibility values of the same minerals. |
| 4024 | Computer 170
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CEST MRI with dual-echo readout for the functional assessment of transplanted kidney in vivo: a preliminary study |
1Department of Diagnostic and Interventional Radiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany, 2Department of Nephrology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany, 3Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany |
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In this study we present the first application of dual-echo CEST MRI technique in renal transplant recipients. Our goal was to optimize the CEST-MRI acquisition and analysis for kidney graft imaging at 3T, which remains technically challenging and volatile due to large B0 inhomogeneity and presence of fat. Strong lipid signals upfield from the water resonance may lead to erroneous CEST contrast. In this preliminary work we demonstrate that the combination of dual-echo CEST with Dixon provides effective fat signal removal, allowing for more accurate quantification of the CEST effects in the transplanted kidney. |
| 4025 | Computer 171
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Analysis of different phase unwrapping methods to optimize QSM in the abdomen |
1Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany, 2Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany |
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We evaluated six different phase unwrapping algorithms for their use in QSM in the abdomen. Therefor a numerical phantom of the abdomen was simulated using a forward model. The resulting unwrapped phases and susceptibility maps were compared with the ground truth and root mean squared error maps were calculated. Results suggest that the “graph-cuts” algorithms should be used for phase unwrapping in the abdomen, as it was the most robust around the lungs and bones and further showed the smallest difference to the ground truth susceptibility. |
| 4026 | Computer 172
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Correlation between CT and QSM in the brain |
1Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan, 2Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan, 3Integrated Clinical Education Center, Kyoto University Hospital, Kyoto, Japan, Kyoto, Japan |
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Quantitative susceptibility mapping (QSM) is a technique which can provide quantitative values of magnetic susceptibility, and thus is a useful tool for differentiating hemorrhage from calcification. Computed tomography (CT) is also used for evaluation of hemorrhage and calcification by using CT values. However, the correlation between CT and QSM has not been much investigated. In this study, we found positive correlations between CT values and susceptibility in the globus pallidus and hemorrhagic lesions. Negative correlations were observed in the choroid plexus and calcified lesions. Our results may help radiologists revisit the CT values based on the susceptibility values calculated from QSM. |
| 4027 | Computer 173
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MRI Susceptibility Mapping Shows Decreased Venous Oxygen Saturation in Sickle Cell Anaemia |
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Developmental Neurosciences, UCL Great Ormond Street Hospital Institute of Child Health, London, United Kingdom |
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Ischemic stroke is a common and severe occurrence in Sickle Cell Anaemia (SCA) but no accurate screening measures currently exist for adults. Changes in venous oxygen saturation (Yv) have been suggested as a potential biomarker but measuring Yv in vivo is challenging. This work explores the potential of MRI susceptibility mapping to measure Yv in SCA subjects. Susceptibility-mapping-based measures of Yv were compared between 25 SCA subjects and 15 healthy controls. Significantly lower Yv was measured in the superior sagittal sinus in the SCA group compared to healthy controls, showing that QSM is sensitive to changes in Yv in SCA. |
| 4028 | Computer 174
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Deep Quantitative Susceptibility Mapping by combined Background Field Removal and Dipole Inversion |
1Department of Neurology, Medical University of Graz, Graz, Austria, 2Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia |
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Deep learning based on u-shaped architectures has been successfully used as a means for the dipole inversion crucial to Quantitative Susceptibility Mapping (QSM). In the present work we propose a novel deep regression network by stacking two u-shaped networks and consequently both, the background field removal and the dipole inversion can be performed in a single feed forward network architecture. Based on learning the theoretical forward model using synthetic data examples, we show a proof-of-concept for solving the background field problem and dipole inversion in a single end-to-end trained network using in vivo Magnetic Resonance Imaging (MRI) data. |
| 4029 | Computer 175
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Achieving Real-Time QSM Reconstruction Using Deep Neural Network |
1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea, Republic of, 2AIRS medical, Seoul, Korea, Republic of |
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Conventional QSM reconstruction algorithms impose long computation time, which inhibits their adoption for real-time clinical use. In this work, we propose a method that replaces conventional iterative algorithms for background removal and dipole inversion with two deep neural networks. The reconstruction results demonstrate comparable performance to the previous outcomes while the new method takes only 3 seconds (up to 106 times faster!), which is unparalleled to conventional methods. |
| 4030 | Computer 1
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Do we still need mathematical modeling in the age of deep learning? A case-study comparison of the Tofts model versus end-to-end deep learning in prostate cancer segmentation |
1Biomedical Translational Imaging Centre, Halifax, NS, Canada, 2Faculty of Computer Science, Dalhousie University, Halifax, NS, Canada, 3Nova Scotia Health Research Foundation, Halifax, NS, Canada, 4Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada, 5Department of Pathology, Dalhousie University, Halifax, NS, Canada |
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The rise in popularity of deep learning is revolutionizing the way biomedical images are acquired, processed, analyzed. Just a few years ago, extracting high-level understanding from biomedical images was a process restricted to highly trained professionals often requiring multidisciplinary collaborations. In the work presented, we showcase a study that compares the performance of a model trained end-to-end using a novel deep learning architecture, versus a model trained on its corresponding state-of-the-art mathematically engineered feature. Results show that end-to-end deep learning significantly outperforms the mathematical model, suggesting that feature engineering will play a less important role in the coming years. |
| 4031 | Computer 2
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Comparison of SENSE-accelerated PROPELLER and Single-shot Turbo Spin-Echo Sequences for Visualization of the Prostatic Urethra during MRI-based Radiotherapy Treatment Planning |
1Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 3Philips Medical Systems, Best, Netherlands, 4Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States |
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At our institution, a Foley catheter is inserted during prostate SBRT simulation to ensure visualization of the prostatic urethra. Our goal was to find an optimal motion-robust T2-weighted pulse sequence that would allow for accurate catheter-free visualization and segmentation of the urethra. We compared Multivane XD (MVXD), a PROPELLER-based multislice TSE sequence with SENSE acceleration to single-shot TSE with SENSE (SSTSE). Two expert GU radiologists scored urethra visibility in MVXD and SSTSE series of equivalent spatial resolution and duration. Urethra visibility scores were significantly higher in the MVXD series and SNR was found to be superior in all MVXD series. |
| 4032 | Computer 3
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Comparison of Stretched-Exponential, IVIM and Monoexponential Diffusion-Weighted Imaging Mathematical Models for Assessment of Tumor Aggressiveness in Prostate Cancer at 3T |
1Kawasaki Medical School, Kurashiki City, Japan, 2Philips Electronics Japan, Osaka, Japan |
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We compared monoexponential and non-Gaussian models including intravoxel incoherent motion imaging (IVIM) and stretched-exponential model in diffusion-weighted imaging (DWI) for characterization of prostate cancer. ADCmean in monoexponential model, D in IVIM, and DDC in stretched model showed high discrimination ability with AUC>0.80 between GS=3+3 and GS≥3+4 tumors as well as GS≤3 + 4 and GS≥4 + 3 tumors, but no significant difference among these metrics. Our study did not show a clear clinical value of non-Gaussian models including IVIM and stretched model compared with standard monoexponential model for assessment of tumor aggressiveness in prostate cancer. |
| 4033 | Computer 4
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Optimal b-Value for Superpixel based Automatic Prostate Gland Segmentation using Diffusion-Weighted Imaging |
1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Department of Electronics & Communication Engineering, Amity University, Noida, India, 3Department of NMR, All India Institute of Medical Sciences Delhi, New Delhi, India, 4Department of Radiology, All India Institute of Medical Sciences Delhi, New Delhi, India, 5Department of Biomedical Engineering, All India Institute of Medical Sciences Delhi, New Delhi, India |
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Accurate segmentation of the prostate gland is a challenging task due to the high variability of prostatic anatomic structures. The diagnostic accuracy of diffusion-weighted-imaging (DWI) to detect prostate cancer (PCa) is well established. Proper delineation using DWI of the prostate gland can take an essential part in the computer-aided-diagnosis of PCa. The purpose of this study is to automatic segmentation of prostate-gland using superpixel-based segmentation in DWI and select the optimal b-value of DWI for segmentation. Experimental results provide a close match to radiologist manual delineation and able to determine the optimal b-value of DWI for superpixel-based prostate-gland segmentation. |
| 4034 | Computer 5
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Ensemble learning-based analysis of T1-weighted and T2-weighted magnetic resonance (MR) radiomics for the prediction of prostate cancer grades with small-scale cohort |
1Baoji Central Hospital, Baoji, China |
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Traditionally, PCA diagnosis and classification are based on prostate specific antigen (PSA) levels, ultrasound and biopsy. This study combines Adasyn and XGBOOST methods to compare the predictive effects of T1-weighted, T2-weighted and T1-T2 co-registration MR images on prostate cancer. The results showed that the integrated learning algorithm using XGBoost can effectively predict prostate cancer grade based on T2WI radiomics features，and T2WI has a better prognostic performance compared with T1-T2 fusion images. |
| 4035 | Computer 6
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Cascading Classifiers Improve Prostate Segmentation |
1Electrical Engineering and Computer Science, Milwaukee School of Engineering, Milwaukee, WI, United States, 2Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 3Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, United States, 5Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States, 6Biostatistics, Medical College of Wisconsin, Milwaukee, WI, United States, 7Pathology, Medical College of Wisconsin, Milwaukee, WI, United States |
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We evaluated the U-Net segmentation model on prostate segmentation using data from 39 patients, achieving a Dice score of 73.9%. We improved segmentation performance by applying a convolutional neural network (CNN) to determine whether slices have prostates. Images with prostates are then forwarded to a U-Net model for segmentation. Our two-phase approach achieves a higher Dice score of 85.2%. |
| 4036 | Computer 7
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Evaluating effect of Combination and Number of Multiple b-values in IVIM Analysis of Prostate |
1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Department of Radiology, All India Institute of Medical Sciences Delhi, New Delhi, India, 3Department of Physics, Indian Institute of Technology Delhi, New Delhi, India, 4Sydney Imaging and School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, Australia, 5Department of Biomedical Engineering, All India Institute of Medical Sciences Delhi, New Delhi, India |
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Optimization of b-values in DWI-IVIM is necessary for precision and reproducibility of parameter estimation. The IVIM biexponential model with Total variation correction (BE+TV) method was used here, which reduces sudden changes in parameter values and removes non-physiological heterogeneity in maps. Various b-value combinations were utilized in prostate: 4, 8 and 13 b-values. 8 and 13 b-values showed similar trend in coefficient of variation (CV), which was confirmed using Bland-Altman plots, including comparable qualitative maps; in contrast, 4 b-values showed variable CV and noisy maps. In prostate, 8 b-values can be used with Total Variation method for faster acquisition protocol and low variability in parameter maps. |
| 4037 | Computer 8
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Potential utility of T1 rho imaging for diagnosis of cystic tumor |
1Diagnostic Radiology, Saitama Medical Center International Medical Center, Saitama, Japan |
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T1 rho imaging is sensitive to the tissue macromolecular inclusion such as proteoglycan of meniscus cartilage. In this study, we demonstrated T1 rho values were differ in ovarian cystic tumors and not in hepatic solid tumors. |
| 4038 | Computer 9
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Value of MR placental protusion sign in predicting postpartumhemorrhage in patients with placenta previa |
1Department of Radiology, First Hospital of Jilin University, Chang, China |
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Objective: To explore the MRI findings of placental protusion sign in predicting postpartum hemorrhage in pa—tients with placenta previa． Methods: Totally 35 4 placenta previa patients with whole clinical data underwent MR scaning 2weeks before operation．Association of postpartum hemorrhage and placental protusion sign was analyzed． Results: Among354 patients with placental previa，the age of the pregnant women(#一4．34，P一0．04)，gestational age at delivery(z2—5．19，P一0．02)and the number of cesarean sections(Z2=44．85，P<O．01)had associated with postpartum hemorrhage．Eight cases had placental protusion sign in MRI，while 6 cases occurred postpartum hemorrhage．The incidence of postpar—tum hemorrhage was 75．00％(6／8)and 12．72％(44／346)in patients with placenta accreta and with placental abruption。respectively(3[2—20．14，P<O．01)．The sensitivity，specificity，odds ratio(95％confidence interval)and positive likeli—hood ratio of predicting postpartum hemorrhage was 12．00％(6／50)，99．34％(302／304)，20．59(4．03，105．23)and15．68，respectively. Conclusion MRI placental protrusion sign has important clinical reference value in predicting postpar—tum hemorrhage． |
| 4039 | Computer 10
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MR manifestations of polypoid endometriosis: Clinical feasibility of conventional and advanced MR techniques |
1Department of Radiology, Tokushima University, Tokushima, Japan, 2Department of Radiological Technology, Tokushima Bunri University, Kagawa, Japan |
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Polypoid endometriosis (PE) is a rare variant of benign endometriosis and may mimic malignant tumors. MR manifestations of five women with pathologically proven PE were retrospectively evaluated. PE was associated with pelvic endometriosis (4/5) with “black rim sign” (3/5), and with adenomyosis (5/5). PE showed high intensity on T2WI (5/5), high intensity hemorrhagic foci on T1WI (3/5), hemorrhagic signal voids on susceptibility-weighted sequences (2/2), high intensity on DWI (4/4) with relatively high ADC values (mean, 1.67 x 10-3 mm2/s), gradually increasing time-intensity curve pattern on DCE-MRI (4/4) with intense contrast-enhancement (4/5) or weak contrast-enhancement (1/5, with malignant transformation). |
| 4040 | Computer 11
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Clinical utility of susceptibility-weighted MR sequences for the evaluation of adnexal torsion |
1Department of Radiology, Tokushima University, Tokushima, Japan, 2Department of Radiological Technology, Tokushima Bunri University, Kagawa, Japan |
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Because venous thrombus within the twisted vascular pedicle is a specific pathological finding for adnexal torsion, to reveal the thrombus by MRI may be diagnostic. Surgically proven five benign ovarian masses with torsion were retrospectively evaluated. High intensity venous thrombus within the twisted vascular pedicle on fat-saturated T1WI were detected in four lesions (80%) but not in one acute torsion, whereas signal voids on susceptibility-weighted MR sequences (SWS) were detected in all five lesions (100%). SWS also revealed hemorrhagic infarction of all five ovarian masses with torsion, whereas fat-saturated T1WI could demonstrate high intensity hemorrhagic infarction in four lesions. |
| 4041 | Computer 12
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Accuracy of dynamic contrast-enhanced magnetic resonance imaging in the diagnosis of prostate cancer: meta-analysis |
1The General Hospital of Ningxia Medical University, Yinchuan, China |
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The goals of this meta-analysis were to assess the effectiveness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with prostate carcinoma (PCa) and to explore the risk profiles with the highest benefit. Compared with T2-weighted imaging (T2WI), DCE was statistically superior to T2. In conclusion, DCE had relatively high specificity in detecting prostate cancer (PCa) but relatively low sensitivity as a complementary functional method. DCE-MRI might help clinicians exclude cases of normal tissue and serve as an adjunct to conventional imaging when seeking to identify tumor foci in patients with PCa. |
| 4042 | Computer 13
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Imaging characteristics of ovarian sclerosing stromal tumor |
1Department of Radiology, Shenzhen Mental Health Center, Shenzhen Kangning Hospital, Shenzhen, China |
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Sclerosing stromal tumor (SST) is an extremely rare benign sex cord-stromal tumor of the ovary. Due to its clinical presentation and imaging findings are similar to those of borderline or malignant epithelial tumors and other sex cordstromal tumors, accurate preoperative clinical diagnosis can be very difficult. This study evaluated magnetic resonance imaging and computed tomography features and pathological findings of SST of ovary and the correlation between them. The results demonstrated that MRI examination with dynamic and delayed enhancement could play a critical role in making appropriate diagnosis preoperatively when combined with clinical information. |
| 4043 | Computer 14
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Evaluation of DWI with lymphovascular space invasion and without lymphovascular space invasion in the stage I endometrial Carcinoma |
1the first Affiliated Hospital of Dalian Medical University, Dalian, China, 2the First Affiliated Hospital of Dalian Medical University, Dalian, China, 3GE Healthcare, Beijing, China |
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Endometrial cancer is one of the most commonly diagnosed gynecologic malignancies in developed countries. The fundamental extent of the operation involves hysterectomy and bilateral salpingo-oophorectomy for the endometrial carcinoma. The presence of LVSI is associated with lymph node metastases. However, Lymphadenectomy can’t improve the survival rate and has a reported higher rate of postoperative complications in endometrial cancer patients. So lymphadenectomy is a controversial issue in recent years. LVSI is a crucial factor in determining the lymphadenectomy and cannot be detected on traditional MR imaging. |
| 4044 | Computer 15
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ADC mean based on a b-value combination of 0 and 1500 s/mm2 would be appropriate as a clinical biomarker for uterine endometrial lesion |
1Diagnostic Radiology, Sapporo Medical University, Saporo, Japan, 2Radiology and Nuclear Medicine, Sapporo Medical University Hoispital, Sapporo, Japan |
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Among several combinations of b-values and ADC histogram metrics, ADC mean calculated with a b-value combination of 0 and 1500 s/mm2 showed high repeatability and a significant correlation with grading of endometrioid adenocarcinoma. |
| 4045 | Computer 16
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Could Whole-Tumor Histogram and Texture Analysis of conventional DWI and DKI Identify Histologically Features of Rectal Cancer? A Preliminary Study |
1Fudan University Shanghai Cancer Center, Shanghai, China, 2Application development, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 3MR Scientific Marketing, Siemens Healthcare, Shanghai, China |
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We investigate the potential of the whole-tumor histogram and texture analysis of the conventional DWI and DKI derived parameters to predict the histology of rectal cancer. Our study demonstrated that the whole-tumor histogram features of ADC and DKI maps could depict the histology of rectal cancer. |
| 4046 | Computer 17
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DCE-MRI and T2* measurement of the endometrium in the menstrual and secretory phases: preliminary data in women with normal menstrual bleeding |
1Edinburgh Imaging Facility QMRI, The University of Edinburgh, Edinburgh, Scotland, 2Centre for Inflammation Research, The University of Edinburgh, Edinburgh, Scotland, 3Centre for Reproductive Health, The University of Edinburgh, Edinburgh, Scotland, 4BHF Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland |
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Heavy menstrual bleeding (HMB) affects approximately 1 in 4 menstruating women per year in the UK and has a severe impact on sufferers’ quality of life. Medical treatments are available but side effects are common and the underlying physiological mechanisms of HMB remain unclear. We imaged eight women with normal menstrual bleeding during the menstrual and secretory phases of the cycle, measuring endometrial T2*, microvascular plasma flow and microvascular plasma volume. We saw a shorter T2* at menstruation, adding to the evidence from other techniques that hypoxia may be important in cessation of bleeding and endometrial repair. |
| 4047 | Computer 18
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Value of the heterogeneity of intravoxel diffusion (α) in diagnosing stage IA and IB of endometrial carcinoma |
1radiology, the first Affiliated Hospital of Dalian Medical University, dalian, China, 2the First Affiliated Hospital of Dalian Medical University, dalian, China, 3GE Healthcare, Beijing, China |
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Preoperative information about depth of myometrial invasion is essential in tailoring the surgical approach for endometrial carcinoma (EC) patients in stage I. To evaluate the value of stretched-exponential models of intravoxel incoherent motion (IVIM) in the differential diagnosis between stage IA and IB of endometrial carcinoma. In this work, we found it is feasible that IVIM sequence derived α value can be applied in the differential diagnosis between stage IA and IB of endometrial carcinoma, which can provide detailed information for clinical treatment. |
| 4048 | Computer 19
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MR features including ADC values of Uterine Carcinosarcoma |
1radiology, the first Affiliated Hospital of Dalian Medical University, dalian, China, 2the First Affiliated Hospital of Dalian Medical University, dalian, China |
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Uterine carcinosarcoma(UCS) is a rare and aggressive tumor with universally poor prognosis. To reinforce the knowledge of uterine carcinosarcoma(UCS) and improve the preoperative diagnostic accuracy on magnetic resonance imaging(MRI). A retrospective imaging review was performed of the MR images of 12 patients with uterine carcinosarcoma. In this study, we summarized its MRI features. |
| 4049 | Computer 20
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MRI changes of pubic symphysis injuries in primiparous women |
1Peking University Third Hospital, Bei Jing, China |
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Objective: MRI changes of pubic symphysis injuries of primiparas and its relationship with pubic symphysis pain and mode of delivery. Methods: 20 primiparas with MRI, were divided into cesarean, normal vaginal delivery and high-risk vaginal delivery. MR changes were observed. Results : pubic symphysis fibroadenoma avulsion was significantly correlated with pubic symphysis pain. Width of pubic symphysis of the primiparas was wider. primiparas had pubic bone marrow edema, which was not associated with pubic symphysis pain. 1 case pubic fracture. MRI changes were not associated with mode of labor. Conclusion: The severy pubic symphysis pain may be related to the symphysis pubis fibrocartilage avulsion and was not related to the pubis bone marrow edema. |
| 4050 | Computer 21
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The value of R2* in quantitative evaluation the biological behavior of endometrial carcinoma: a preliminary study |
1The First Affiliated Hospital of Dalian Medical University, Dalian, China |
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R2* value can be used as a MR non-enhancement quantitative index for evaluating the biological behavior of EC. |
| 4051 | Computer 22
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DCE-MRI texture analysis in differentiating adenocarcinoma and squamous cell cancer of cervix |
1Radiology, Cental Hospital of Wuhan,Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Radiology, Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 3Philips Healthcare, Shanghai, China |
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Adenocarcinoma comprises 25% of cervical cancers and has a bad prognosis and poor outcome of radiotherapy and chemical treatment in the advanced stage. Here, we report a radiomics method with multi-class texture features from semi-quantitative DCE-MRI maps to distinguish adenocarcinoma from squamous cell cancer. Multivariate models were trained on the training cohort and their performance was evaluated on the 5-fold cross-validation cohort using the area under ROC curve (AUC), accuracy, specificity and sensitivity. Our results showed the mean sensitivity, specificity, PPV, NPV and AUC were 0.96, 0.889, 0.967, 0.889 and 0.967 respectively in diagnosing adenocarcinoma of cervix. |
| 4052 | Computer 23
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Exploring analytical models of the diffusion MR signal in non-pregnant cervical tissue in 3T |
1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Centre for the Developing Brain, King’s College London, London, United Kingdom, 3Division of Women’s Health, King’s College London, London, United Kingdom |
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Preterm Birth is a major healthcare problem and its appropriate prediction remains a challenge. Extensive research utilising advanced MR protocols has been undertaken on the cervical malignancy, but cervical structure and remodelling in term and preterm pregnancies is little studied. As part of a larger project, this work aims to explore model-based diffusion MRI microstructural models along the non-pregnant cervix. We compare multi-compartment microstructure models to analyse the diffusion signal. Initial results reveal that more complex models than the Apparent Diffusion Coefficient are required to characterise the cervical tissue microstructure. |
| 4053 | Computer 24
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Cervix heterogeneity: recommendations for scanning the non-pregnant cervix |
1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Centre for the Developing Brain, King’s College London, London, United Kingdom, 3Division of Women’s Health, King’s College London, London, United Kingdom |
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Imaging the non-pregnant cervix requires some unique considerations. The cervix has numerous functions including ensuring the fetus is maintained within the uterine cavity until the onset of labour. Alterations in the integrity of cervical tissue are purported to be one of the mechanisms which may contribute to preterm delivery. Quantitative MRI techniques can be used to characterise tissue microstructure however this has not been applied to date to the non-pregnant cervix in the absence of malignancy. This works aims to highlight some limitations and aspects to consider prior to scanning a non-pregnant cervix. |
| 4054 | Computer 25
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Pelvic endometriosis: The added value of the R2*MFGRE sequence in magnetic resonance imaging |
1QiLu hospital of Shandong University, Shandong Jinan, China |
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Purpose: The diagnostic accuracy of endometriosis by conventional magnetic resonance imaging (MRI) sequences is not satisfactory. Minimum endometriosis is particularly challenging to diagnose, which may lead to recurrence or incomplete relief of symptoms after surgery. The R2* multi-fast gradient echo (R2*MFGRE) sequence with the highest sensitivity of hemorrhage in endometriosis may help to address this problem. Methods: We selected 54 adenomyosis or endometriosis patients and referred them to MRI including the R2*MFGRE sequence and analyzed the results. Conclusion: The analysis revealed that the R2*MFGRE sequence may provide useful information to help diagnosing endometriosis. |
| 4055 | Computer 26
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Fetal cardiac 4D phase-contrast MRI using Doppler ultrasound gating to visualize fetal hemodynamics in utero: preliminary results |
1University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Department of Obstetrics and Fetal Medicine, Germany, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3Department of Radiology, University Hospital Cologne, Cologne, Germany |
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In this study 2D and 4D phase contrast MRI angiography was performed in six foetuses (gestational week 30-35) with direct cardiac gating using Doppler ultrasound at 1.5T. The fetal vasculature and hemodynamics could be visualised in detail including the ductus arteriosus. Blood flow was similar between 2D and 4D PCA. This method may provide an important additional tool for prenatal diagnosis of CHD such as coartation of the aorta. |
| 4056 | Computer 27
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Feasibility of free-breathing T1-weighted 3D radial VIBE for fetal MRI in various anomalies |
1Department of Radiology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, 2Diagnostic Imaging, SIEMENS Healthcare, Shanghai, China, 3R&D, Diagnostic Imaging, SIEMENS Healthcare, Erlangen, Germany |
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Traditional breath-hold, fat-suppressed T1-weighted sequences (T1W images) may be degraded by motion artifacts arising from both the mother and fetus. Images obtained with the radial VIBE sequence had a higher overall image quality score than Cartesian sampled 3D VIBE T1W images and less motion artifact in various fetal regions. Fetal lesions presented in radial VIBE images had good lesion conspicuity and edge sharpness. |
| 4057 | Computer 28
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The reduction of perfusion fraction in placenta increta --a pilot study of placental perfusion using IVIM MRI |
1Department of Radiology, the first Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 2MR Research China, GE Healthcare, People’s Republic of China, Bei Jing, China |
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Placenta increta, a serious threat to maternal and fetal life, is difficult to distinguish by traditional MRI. In this study, IVIM imaging was used for the first time to detect the perfusion level of some placenta implanted, and it was found that the perfusion fraction was significantly lower than that of the normal placenta. That is help for establishing a new method for clinical diagnosis of placental implantation, especially placenta non-percreta. |
| 4058 | Computer 29
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Diffusion weighted imaging evaluation of cerebral changes in twin pregnancies with one fetus demise |
1Radiology, Peking University Third Hospital, Beijing, China |
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Diffusion-weighted imaging (DWI) has been applied to fetal MRI and provides important information in evaluating the microstructures. Apparent diffusion coefficient (ADC) value is derived from DWI sequence. The aim of this study is to compare ADC values of brain in surviving fetus of one fetus demise with normal fetuses using diffusion weighted imaging and to find the differences and underlying cerebral microstructure changes. Decrease of ADC values were detected in surviving fetus of one twin demise. DWI and ADC values are very useful for detecting underlying changes, even changes of signal are not visible on conventional sequences. |
| 4059 | Computer 30
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Joint placental angiography with perfusion and apparent oxygenation mapping |
1Biomedical Engineering,School of Biomedical Engineering & Imaging Sciences, Kings College London, London, United Kingdom, 2Department of Women and Children’s Health, School of Life Course Sciences, Kings College London, London, United Kingdom, 3Centre for the Developing Brain, School of Biomedical Engineering & Imaging Sciences, Kings College London, London, United Kingdom |
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In this work we combine two novel methods for imaging the oxygen transfer system between maternal and fetal circulations, 1) a motion robust angiography acquisition and 2) a combined perfusion and oxygenation acquisition. This enables the matching of functional regions of placenta to the vessels that supply them in utero. This may provide further insight into the vascular origins of major obstetric diseases such as fetal growth restriction and pre-eclampsia. |
| 4060 | Computer 31
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Multislice and Multidimensional Blood Flow Mapping in Fetal Congenital Heart Disease Using Highly Undersampled Phase-Contrast MRI |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada, 3Cardiology, Hospital for Sick Children, Toronto, ON, Canada, 4Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 5Paediatrics, University of Toronto, Toronto, ON, Canada |
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In this study, multislice and multidimensional fetal blood flow mapping was performed using highly undersampled radial phase contrast MRI. The goal of this work was to visualize intracardiac flow in human fetuses with congenital heart disease, where complex flow patterns are difficult to capture with conventional, 2D phase contrast techniques. Reconstructions were performed using compressed sensing, with retrospective motion correction and image-based cardiac gating. The developed technique allowed whole fetal heart coverage in reasonable time and provides insight into multi-directional intracardiac flows. We present results from 5 human fetuses with congenital heart disease and demonstrate the first multi-directional intracardiac flows obtained by MRI. |
| 4061 | Computer 32
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Changes in placental oxygenation in subclinical uterine contractions in the third trimester |
1Sir Peter Mansfield Centre, University of Nottingham, Nottingham, United Kingdom, 2Medical Physics, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom, 3Life Sciences, University of Nottingham, Nottingham, United Kingdom, 4CHild Health, Obstetrics and Gynaecology, University of Nottingham, Nottingham, United Kingdom |
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Subclinical uterine contractions in the third trimester have been detected with MRI in recent years and we regularly observe these contractions in 10 minute longitudinal scans. In a small pilot study, single echo-planar imaging T2* weighted scans and associated quantitative susceptibility maps suggest that the uterine contractions are localised to the placenta and that the placenta is more oxygenated after the contraction. We hypothesise that the contractions have the function of mixing of blood in the placenta to aid transport through what is otherwise a low flow system. |
| 4062 | Computer 33
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Model-Driven Registration for 3D Placental Diffusion-Weighted MRI |
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, 2Department of Medical Physics & Biomedical Engineering, University College London, University College London, London, United Kingdom, 3Institute for Women’s Health, University College London, London, United Kingdom, 4Medical Physics, University College London Hospital, London, United Kingdom, 5Centre for Medical Imaging, University College London, London, United Kingdom, 6University Hospital KU Leuven, Leuven, Belgium, 7NIHR University College London Hospitals Biomedical Research Centre, London, United Kingdom |
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The placenta is essential for successful pregnancy outcome. Placental imaging is however challenging due to maternal breathing motion and fetal movements, making motion correction important for subsequent analysis. This study introduces an iterative model-based registration technique which incorporates a joint placenta-specific signal model for diffusion and relaxation data into the motion correction process. We compared our method to a pre-existing method used for contrast-enhanced data making use of principal component analysis. Our results suggest that the proposed method significantly improves alignment of free-breathing placenta relaxation and DW-MRI data and evidence that the precision of markers of function obtained in placenta can be improved. |
| 4063 | Computer 34
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Fetal dynamic phase-contrast angiography using Doppler ultrasound gating and comparison with Doppler ultrasound measurements |
1Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2NortHH Medical GmbH, Hamburg, Germany, 3Diagnsotic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 4UCSF Benioff Children's Hospital Oakland, Oakland, CA, United States, 5Gynaecology & Obstetrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany |
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In this prospective study 2D PC-MRI angiography was performed in nine human fetuses (gestational age 32.2 ± 2.4 weeks) using a novel MR compatible DUS device for gating of the fetal heart at a 1.5T MR scanner. The novel MR compatible DUS device for fetal cardiac gating allowed successful application of PC-MRI angiography and quantification of hemodynamics in the fetal AoD. This new technique for direct gating of the fetal heart demonstrates the diagnostic potential of PC-MRI for the quantification of fetal hemodynamics. |
| 4064 | Computer 35
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Pattern Analysis of Placental Blood Flow Distribution using ASL MRI |
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 4Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States |
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Arterial Spin Labeling MRI is a promising approach to assess blood flow to the placenta. Although previous studies have largely attempted to quantify global perfusion, we believe that the unique physiology of blood flow through the placental intervillous space rather than through capillaries warrants regional pattern analysis. We present an image analysis framework leveraging a spline-based transform of the image coordinates, watershed segmentation, and clustering analysis. We report Bayesian statistics to quantify features of blood flow distribution and the degree of uncertainty at the uteroplacental interface. |
| 4065 | Computer 36
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Measurement of Uterine Artery and External Iliac Artery Pulse Wave Velocity using 4D Flow MRI |
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 4Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States |
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Maintenance of blood supply to the placenta is believed to be dependent on the geometric and hemodynamic properties of the uteroplacental vasculature. In this study we present an MRI method for measuring pulse wave velocity in the uterine arteries. In 6 healthy pregnant subjects, we measured path length and time-to-peak of the velocity waveforms in the uterine arteries and external iliac arteries. The uterine arteries have lower pulse wave velocity than the external iliac arteries (5.5±2.5 vs. 12.9±4.6 m/s, p=3x10-5), indicating possible biomechanically greater compliance. |
| 4066 | Computer 37
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Optimized High-Permittivity Pads Can Reduce SAR and Increase Transmit Field Homogeneity in Fetal Imaging at 3T |
1Circuits and Systems Group, Delft University of Technology, Delft, Netherlands, 2C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Leiden, Netherlands |
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One of the main concerns in fetal MRI is the amount of power that is deposited both in the fetus and the mother. In this work, we show that a well-designed high-permittivity pad can tailor the energy of the RF field such that the transmit efficiency increases and the field becomes more homogeneous. The increase in transmit efficiency subsequently enables a substantial reduction in the SAR in both the mother and the fetus for models of the third, seventh, and ninth months of gestation. |
| 4067 | Computer 38
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Classification and prognosis of fetal hepatic hemangioendothelioma using MRI |
1MRI, Shandong Medical Imaging Research Institute, Shandong University, Jinan, China, 2Ultrasound, Shandong Medical Imaging Research Institute, Shandong University, Jinan, China, 3MR Collaboration AP, Siemens Healthcare, MR Collaboration AP, Beijing, China, 4Obstetrics, Jinan Maternity and Child Care Hospital, Jinan, China |
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The aim of this study was to investigate the MRI features and classification of 23 fetal hepatic hemangioendothelioma (HAE) and to compare the prognosis of HAE-I and HAE-II. The results showed that fetal HAE-I tends to be more vascular in the lesion, and the larger the focus, the more prone to complications. Once complications occur, the prognosis is poor; however, in HAE-II, the lesions are always smaller, there is a lack of vascularity, they are homogeneous, and the prognosis is good. Our study demonstrated that the MRI features and classification of HAE can effectively predict and guide prognosis. |
| 4068 | Computer 39
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Assessment of placental microcirculation by joint analysis of flow compensated and non-flow compensated intravoxel incoherent motion data |
1Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, 2Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 3Computer Science and Artificial Intelligence Laboratory (CSAIL), Massachusetts Institute of Technology, Cambridge, MA, United States, 4Department of Pathology, Massachusetts General Hospital, Boston, MA, United States, 5Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 6Department of Radiology, Harvard Medical School, Boston, MA, United States, 7Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 8Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 9Maternal-Fetal Medicine, Obstetrics and Gynecology, Massachusetts General Hospital, Boston, MA, United States, 10Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States |
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Using diffusion weighted imaging and the intravoxel incoherent motion model (IVIM) of blood flow in capillaries, we can measure placental properties relating to maternal and fetal blood flow and perfusion. In this study, we focused on improving the accuracy and precision of the estimated parameters in IVIM imaging by using joint analysis of flow compensated and non-flow compensated diffusion data. With flow compensation, we observed strong re-phasing, approximately cancelling the blood flow effect and allowing more accurate and consistent estimation of diffusion and perfusion measures. |
| 4069 | Computer 40
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Fetal Brain-Heart-Placental Interactions with Acute Hypoxia Challenge in Genetic Mouse Models of Hypoplastic Left Heart Syndrome with in utero 4D Dynamic MRI |
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Developmental Biology, University of Pittsburgh, Pittsburgh, PA, United States, 3Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States |
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The objective of this study is to develop 4D time-resolved high-resolution in utero MRI for simultaneous interrogation of placenta, heart and brain development and function in genetic mouse models of hypoplastic left heart syndrome. The structural and functional imaging of the fetal heart, brain, and placenta can be correlated with genotype. In addition, temporal and spatial characteristics of BOLD responses to acute hypoxia challenge can be derived. |
| 4070 | Computer 41
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Comparison of fetal lung diffusivity in cases of pulmonary hypoplasia to normative MRI data |
1Boston Children's Hospital and Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States |
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Typically the fetal lungs are measured using structural magnetic resonance (MRI) or ultrasound images, but improvements in fetal MR imaging have made diffusion weighted imaging (DWI) feasible for even fetal patients. Previously it was shown that lung diffusion could be reliably measured for fetuses with normal lung development and that diffusivity increased with gestational age (GA). In this study we applied the same techniques to measure lung diffusivity in patients indicated for congenital diaphragmatic hernias. We then compared diffusivity measurements for both the herniated-side, left lung and right lung to normative lung diffusivity data. |
| 4071 | Computer 42
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Fetal Brain Tissue Characterization at 1.5 T using STAGE |
1Department of Radiology, Wayne State University School of Medicine, DETROIT, MI, United States, 2Department of Radiology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, 3The MRI Institute for Biomedical Research, Bingham Farms, MI, United States, 4Department of Biomedical Engineering, College of Engineering, Wayne State University, DETROIT, MI, United States |
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MRI-based tissue properties such as T1 and proton spin density are known to be important biomarkers of fetal brain maturation. However, fetal motion poses a big challenge in MRI due to long scan durations. Henceforth, there is lack of knowledge about the MRI properties of the human fetal brain tissue. To address these issues, in this study we use a rapid multiparametric method referred to as Strategically Acquired Gradient Echo (STAGE) imaging to obtain T1 and proton density maps of the fetal brain and generate T1-weighted images with enhanced tissue contrast in two minutes. |
| 4072 | Computer 43
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T1 and T2 mapping of the placenta and fetal brain with magnetic resonance fingerprinting (MRF) during maternal hyperoxia |
1Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 3Harvard-MIT Health Sciences and Technology, IMES, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Quantitative MRI may improve diagnosis and monitoring of placental disease by characterizing baseline oxygen content and dynamic oxygen transport during hyperoxia. MRF permits fast quantitative imaging of the adult brain and heart, but use during pregnancy targeting the placenta and fetal brain presents challenges due to motion and large B1+ variation. We tested the accuracy of MRF in phantoms and then scanned pregnant mothers, estimating T1 and T2 of the placenta and fetal brain. MRF-based T1 and T2 mapping is a promising technique to determine placental oxygenation at baseline and oxygenation changes in the placenta and fetal brain after hyperoxia. |
| 4073 | Computer 44
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Reliable assessment of apparent diffusion coefficient in normal and ventriculomegaly fetal brains |
1Centro Fermi - Museo storico della Fisica e centro studi e ricerche Enrico Fermi, Rome, Italy, 2SAIMLAL, Sapienza University of Rome, Rome, Italy, 3Radiological Sciences, Sapienza University of Rome, Rome, Italy, 4Physics, Sapienza University of Rome, Rome, Italy, 5Physics, CNR-Institute for Complex Systems, Rome, Italy |
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Ventriculomegaly (VM) is one of the most common disease in fetuses; however, DWI studies during gestation are scarce. In this work, DWI was performed in normal and VM fetal brains at different gestational ages (GA) and ADC was calculated. Denoising and artifacts corrections were used to improve signal-to-noise ratio and the reliability of measures. We found significant variations in ADC as GA increases, reflecting microstructural changes due to brain maturation. Moreover, ventricles dilatation measured on DWIs provided an accurate classification of VM. DWI with artifacts corrections could be a powerful tool to evaluate brain abnormalities and accurately diagnose VM. |
| 4074 | Computer 45
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Why MRI? Evaluating Acute Abdominal and Pelvic Pain During Pregnancy. |
1Medical College of Georgia at Augusta University, Augusta, GA, United States, 2Feinberg School of Medicine, Chicago, IL, United States, 3Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 4Radiology and Imaging, Medical College of Georgia at Augusta University, Augusta, GA, United States |
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A variety of pathological processes can be the cause of abdominopelvic pain during pregnancy, such as acute appendicitis, acute cholecystitis, hepatic adenoma, spontaneous adrenal hemorrhage, ovarian mature cystic teratoma, ectopic pregnancy, cystic degeneration of an intramural fibroid, and the placenta accreta spectrum. Standard MRI protocols without gadolinium contrast are discussed, as well as protocols for fluid sensitive sequences with and without fat suppression, T1-weighted sequences, and thin slice sequences. These MR imaging techniques are valuable in determining an accurate diagnosis and subsequent management plan for the mother and fetus. |
| 4075 | Computer 46
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Fetal Brain Response to an Auditory Stimulus |
1Biomedical Engineering, Western University, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada, 3Division of Maternal, Fetal and Newborn Health, Children’s Research Institute, London, ON, Canada, 4Obstetrics and Gynaecology, Western University, London, ON, Canada, 5Brain and Mind Institute, Professor of Engineering, Western University, Lodon, ON, Canada, 6Clinical Neurological Sciences, Western University, London, ON, Canada |
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Functional magnetic resonance imaging (fMRI) was used in conjunction with an auditory task to assess fetal activation in the primary auditory cortex. Activation was found in the fetal right Heschl’s gyrus in response to an auditory task. This is a first report of fetal brain response to an “internal” auditory stimulus. |
| 4076 | Computer 47
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Novel Nanoparticle-enhanced T1-Mapping Enables Estimation of Placental Fractional Blood Volume in a Pregnant Mouse Model |
1Radiology, Baylor College of Medicine, Houston, TX, United States, 2Pediatric Radiology, Texas Children's Hospital, Houston, TX, United States, 3Pediatric Oncology, Baylor College of Medicine, Houston, TX, United States |
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Greater than 60% of placentae from low birth weight infants show signs of hypoxic or ischemic injury from vascular hypo-perfusion. Placental fractional blood volume (FBV) is indicative of perfusion and may be used as a marker of local ischemia. Non-invasive methods for the estimation of placental FBV are therefore of interest in the study of placental pathology. In this pre-clinical study, we investigated contrast-enhanced magnetic resonance imaging (MRI) for the estimation of placental FBV in a pregnant mouse model. A high T1 relaxivity blood-pool liposomal-gadolinium (liposomal-Gd) contrast agent, which does not permeate placental barrier in rodents, was used to calculate placental FBV. |
| 4077 | Computer 48
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Functional and Developmental Effects of Zika Virus Infection and Hydroxychloroquine Treatment in Mouse Placenta |
1Physics, Washington University in St Louis, Saint Louis, MO, United States, 2Obstetrics and Gynecology, Washington University in St Louis, Saint Louis, MO, United States, 3Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, United States, 4Center for Reproductive Health Sciences, Washington University in St Louis, Saint Louis, MO, United States, 5Siteman Cancer Center, Washington University in St Louis, Saint Louis, MO, United States |
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Functional and developmental effects of Zika virus (ZIKV) infection and hydroxychloroquine (HCQ) treatment on the murine placenta were measured using MRI and oxygen enhancement to assess placental volume and oxygenation. HCQ treatment helps to prevent adverse placental volume outcomes earlier in gestation, but late-gestation results are similar to those of ZIKV-infected dams. R1 and R2* measurements show that HCQ has a significant effect on placental oxygenation throughout gestation, whereas ZIKV does not significantly affect these metrics. |
| 4078 | Computer 51
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Comparison of Quantitative Pulmonary Ventilation Imaging using 3D-UTE under breath-holding and free-breathing in patients with structural lung disease at 3 T. |
1Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany, 2Application Development, Siemens Healthcare GmbH, Erlangen, Germany |
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UTE-MRI allows morphologic examination of lung parenchyma and acquisition of different breathing states enables determination of quantitative pulmonary ventilation (QV). In 4 patients with lung disease imaging with a prototypical UTE Spiral VIBE sequence during breath-holding was compared with a free-breathing 3D-UTE koosh-ball technique. Different breathing states were acquired, and QV values and the air volume fraction (AVF) were calculated. Both techniques yielded clinically sufficient image quality and comparable results for QV and AVF values. While the breath-hold approach acquires the data in a fraction of time but is dependent on patient compliance, the self-gated free-breathing technique overcomes that problem with the drawback of a longer acquisition time. |
| 4079 | Computer 52
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Validation of Fourier Decomposition Lung MR Perfusion using Breath-hold Correction |
1Medical Radiation Physics & Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden |
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Co-registration of free breathing coronal lung images in Fourier decomposition (FD) lung MRI is a crucial part of the processing pipeline for this technique. It is vital that the registration works on the correct parts of the image and does not interfere with the data in an unfavourable way. This work aims to evaluate the extent to which registration affects the perfusion, and by association the ventilation results of this technique, using a breath-hold acquisition as a gold standard. Results encourage the generation of confidence maps to aid interpretation of FD lung MR results, particularly in regions affected by registration. |
| 4080 | Computer 53
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Free-Breathing Self-Gated 4D-Lung MRI with wave-CAIPI |
1Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany, 2Comprehensive Heart Failure Center Würzburg, Würzburg, Germany |
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The wave-CAIPI technique was applied to self-gated dynamic Lung MRI during free breathing. To prevent synchronization between respiratory motion and phase-encoding, the order of the phase-encoding steps was randomized using non-uniformly distributed, two-dimensional random numbers which oversample the k-space center. Breathing motion was gated using an additionally recorded DC signal. A healthy volunteer was investigated using the proposed method and a standard Cartesian scan for reference. For a scan time of 10:46 min, both methods exhibit comparable image quality. However, for accelerated scans, the wave-CAIPI technique clearly shows reduced residual image artifacts after applying parallel imaging. |
| 4081
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Computer 54
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Real-Time Imaging during Free Breathing for Patient-Friendly V/Q Scan of the Whole Lung in One Minute at 3T |
1Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany, 2Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany, 3Magnetic Resonance, Siemens Healthcare GmbH, Erlangen, Germany |
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MRI techniques like phase-resolved functional lung imaging (PREFUL) offer the possibility for pulmonary ventilation (V) / perfusion (Q) imaging without ionizing radiation or contrast agents. One major drawback of such methods is the long acquisition time, if a whole lung coverage is required. In this study, five healthy volunteers were scanned with a highly accelerated 2D multi-slice real-time PREFUL (RT-PREFUL) acquisition with compressed sensing and parallel imaging reconstruction to establish a V/Q scan of the whole lung in one minute. The comparison with conventional PREFUL technique showed very similar ventilation results and comparable perfusion results with 9-fold acceleration. |
| 4082 | Computer 55
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Magnetization transfer and diffusion-weighted imaging in differential diagnosis of solid pulmonary masses: A comparison study |
1Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xian Yang, China, 2MR Scientific Marketing, Siemens Healthineers, Shang hai, China |
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In this study, magnetization transfer (MT) and diffusion-weighted imaging(DWI) techniques were used to differentiate the solid pulmonary masses. It was found that magnetization transfer can be used to distinguish benign and malignant pulmonary masses. Combining magnetization transfer and diffusion-weighted imaging, the accuracy of differentiation can be further improved. |
| 4083 | Computer 56
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Imaging functional and microstructural changes in the lungs of children born prematurely |
1POLARIS, Academic Radiology, IICD, The University of Sheffield, Sheffield, United Kingdom, 2Department of Child Health, School of Medicine, Cardiff University, Cardiff, United Kingdom |
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Preterm-births account for 10% of worldwide births, and those born at 32 weeks gestation or less have deterioration in their lung function in childhood and beyond. Here we assessed pulmonary micro-structural and functional changes using hyperpolarized 129Xe gas ventilation and diffusion-weighted MRI in three groups of children: (1) those born preterm with FEV1<=85%, (2) born preterm with normal lung function and (3) those born full term with normal lung function. Significant differences in ventilation heterogeneity and the kurtosis of the distribution of mean alveolar dimension were observed between groups. |
| 4084 | Computer 57
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A Comprehensive Pipeline for non-contrast enhanced Pulmonary Vascular 1H MRI |
1Robarts Research Institute, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada, 3Radiation Oncology, Stanford University, Stanford, CA, United States, 4Medical Biophysics, University of Toronto, Toronto, ON, Canada, 5Medicine, Division of Respirology, Western University, London, ON, Canada |
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Structure-function relationships are central to our understanding of pulmonary disease and play an important role in evaluating novel therapies. Many chronic lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), have vascular abnormalities that are not accounted for in current image analysis platforms. Recent MRI developments provide complementary pulmonary vascular structural and functional information and include ultra-short echo time and Fourier-decomposition MRI. To facilitate clinical translation, we developed a comprehensive structure-function pipeline to visualize and measure pulmonary vascular vessel trees and perfusion for patients with severe asthma, a demanding clinical target. |
| 4085 | Computer 58
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Flow-Compensated Ventilation and Perfusion Fourier-decomposition Pulmonary MRI |
1Robarts Research Institute, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada, 3Radiation Oncology, Stanford University, Stanford, CA, Canada, 4Medical Biophysics, University of Toronto, Toronto, ON, Canada, 5Medicine, Division of Respirology, Western University, London, ON, Canada |
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Fourier-decomposition pulmonary MRI ventilation and perfusion maps are subject to substantial flow artifacts stemming from cardiac frequencies which makes lung perfusion measurements complex and in some regions of interest, impossible to acquire. We eliminated flow artifacts by shimming only on cardiac regions, instead of the entire field-of-view. Flow compensation improved vessel resolution and segmentation around the heart but also increased the incidence of off-resonance banding artifacts around the diaphragm. MRI ventilation defect percent was greater in flow-compensated versus uncompensated images as well as hyperpolarized gas MRI, demonstrating that ventilation images are highly sensitive to changes in field inhomogeneities. |
| 4086 | Computer 59
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Self-Gated 2D UTE Lung Ventilation Imaging |
1Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany, 2AG Experimental Cardiovascular Imaging (ExCaVI), University of Ulm, Ulm, Germany |
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Deriving functional lung data by MRI is challenging, but initial studies have proven the applicability of multi-respiratory stage data for deriving fractional lung ventilation data. In this study a two-dimensional ultra-short TE protocol was used to acquire breathhold (expiration and inspiration) and free breathing date of the lung parenchyma. Lung proton density changes and respective fractional ventilation could be assessed with either techniques. Due to the shallow breathing, in the free-breathing approach differences resulted less pronounced as in the breathhold approach. |
| 4087 | Computer 60
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Comparison of 1.5T and 3T 2D UTE Breathhold Lung Imaging |
1Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany, 2AG Experimental Cardiovascular Imaging (ExCaVI), University of Ulm, Ulm, Germany |
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In this study a breathhold two-dimensional ultra-short TE (UTE) protocol was compared for imaging of the lung parenchyma and ventilation at 1.5T and 3T field strength. The resulting SNR values and parameter maps indicate a clear advantage for 3T. Proton fraction and SNR changes (anterior to posterior, expiration vs. inspiration) can be clearly assessed with both field-strength. Different resulting values for the lung and proton fractions need further attention. |
| 4088 | Computer 61
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2D UTE BH lung ventilation imaging at 3T – influence of the repetition time |
1Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany, 2AG Experimental Cardiovascular Imaging (ExCaVI), University of Ulm, Ulm, Germany |
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In this study a two-dimensional ultra-short TE protocol was used to get breath holding (expiration and inspiration) images. It was investigated whether resulting SNR and ventilation and proton density maps can be improved by optimization the TR under given breathhold constraints for multi-slice single breathhold lung imaging. Even though the SNR in the resulting images can clearly be improved by performing an interleaved multi-slice acquisition instead of acquiring slices sub-sequentially, the impact on the resulting parameter maps was not obvious. |
| 4089 | Computer 62
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MultiVane Technique at 1.5T Improved the Quality of Lung MRI: Comparison with Routine T2-Weighted MRI and CT Imaging |
1Radiology, The Longhua Hospital of Shenzhen, Shenzhen, China, 2Graduate School, Medical College of Nanchang University, Nanchang, China, 3Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 4Department of Respiration, The Longhua Hospital of Shenzhen, Shenzhen, China |
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Radiation-free MRI with MultiVane motion correction technique improved the lung MR imaging quality with satisfactory quality compared to routine T2 weighted imaging or CT imaging. In this study, MultiVane lung MRI protocol provided diagnostic performance acceptable in detection of several common lung abnormalities with a good agreement to the findings obtained in routine clinical CT examinations, especially to identify caseation or liquefactive necrosis. However, MRI is less desirable to detect the nodules with calcification. The current lung MRI with non-radiation is feasible. It offers a promising alternative to the clinical standard CT in diagnosis and characterization of pulmonary diseases. |
| 4090 | Computer 63
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Free breathing lung T1 mapping in idiopathic pulmonary fibrosis |
1Academic Radiology, University of Sheffield, Sheffield, United Kingdom |
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A method for free breathing Look-Locker T1 mapping using image registration is presented. This method uses a fitted model inversion recovery signal modulated with respiratory motion to create a set of synthetic images, to which all acquired free-breathing Look-Locker images are registered. The method was implemented in 9 patients with idiopathic pulmonary fibrosis (IPF) and 9 healthy volunteers and the results compared to T1 maps acquired with the same Look-Locker sequence acquired in an inspiratory breathold state for patients with IPF, and inspiratory and expiratory breath hold states for healthy volunteers. Patients with IPF were found to have a lower T1 during free breathing and a higher standard deviation of regional T1 values in the lung when compared to volunteers. |
| 4091 | Computer 64
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Pseudo-diffusion effects in lung MRI |
1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Neuroradiology, University Hospital Wuerzburg, Wuerzburg, Germany, 3Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany |
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Magnetic resonance imaging of lung tissue is strongly influenced by susceptibility effects between spin-bearing water molecules and air-filled alveoli. The measured lineshape, however, also depends on the blood-flow around alveoli that can be approximated as pseudo-diffusion. Both effects are quantitatively described by the Bloch-Torrey-equation, which was so far only solved for dephasing on the alveolar surface. In this work, we extend this model to the whole range of physiological relevant air volume fractions. The results agree very well with in vivo measurements in human lung tissue. |
| 4092 | Computer 65
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Intravoxel incoherent motion diffusion-weighted Imaging of lung: comparison between turbo spin-echo and echo-planar imaging |
1The first affiliated hospital of Guangzhou Medical University, Guangzhou, China, 2Philips Healthcare, Guangzhou, China |
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The image quality of single-shot echo-planar imaging (EPI)-DWI (SS-EPI-DWI) is usually deteriorated by susceptibility artefacts, especially in lung, because EPI sequence is vulnerable to magnetic inhomogeneity and phase error accumulation. This could lead to inabilities of diagnosis or inaccuracy of measurements. In this study, lung DWI were acquired using both single-shot turbo spin-echo (SS-TSE) and SS-EPI techniques. Significantly changes were observed in distortion ratio (DR) between both techniques. SS-TSE-DWI has better image quality and almost zero distortion compared to SS-EPI-DWI. |
| 4093 | Computer 66
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Assessment of scan parameter effects on time resolved bSSFP acquisition for Fourier Decomposition Pulmonary MR |
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany |
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Pulmonary functions play an important role in diagnosis of pulmonary diseases. One method for functional lung MRI is Fourier Decomposition technique, which obtains ventilation and perfusion weighted images from dynamic free-breathing acquisitions. Although this method is validated against well-established methods, its robustness depends on scan parameters and temporal resolution. In this work, we have investigated the effects of common scan parameters on image quality. In vivo results are presented to demonstrate the performance differences in protocols. |
| 4094 | Computer 67
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Quantitative Pulmonary Ventilation Imaging in Patients with Cystic Fibrosis using breath-hold 3D-UTE at 3T |
1Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany, 2Department of Pediatrics, Universtiy Hospital Würzburg, Würzburg, Germany, 3Application Development, Siemens Healthcare GmbH, Erlangen, Germany |
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We demonstrate first results of breath-hold 3D-UTE MRI for ventilation imaging in CF patients. Ten patients underwent 3D-UTE MRI of the lungs. Data were acquired in breath-hold for 5 different breathing states, in order to obtain information regarding the ventilation. 3D-UTE MRI provided sufficient morphologic image quality for the detection of structural lung disease and site-resolved information regarding pulmonary ventilation. Ventilation measurements correlated well with parameters of conventional lung function testing and were in accordance with pulmonary ventilation measured with techniques published recently. The technique could be an innovative method able to enhance diagnosis and monitoring of structural lung disease. |
| 4095 | Computer 68
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Free-Breathing Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Lung Using Compressed-Sensing VIBE |
1Department of Radiology, Hua Dong Hospital,Fudan University, Shanghai, China, 2MR Application Development, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 33. MR Application Predevelopment, Siemens Healthcare, Erlangen, Germany |
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The purpose of this study was to compare the image quality of free-breathing CS-VIBE and TWIST-VIBE in patients with lung disease. In patients who were able to hold their breath well, the images quality of CS-VIBE and TWIST-VIBE were comparable (P＞0.05). In patients who failed to hold their breath during the required period, CS-VIBE allowed for superior image quality, lesion delineation, artifact level, and diagnostic confidence compared to TWIST-VIBE. Our study demonstrated that free-breathing CS-VIBE is feasible for lung imaging for patients who have difficulties holding their breath. |
| 4096 | Computer 69
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Comparison of Therapeutic Effect Prediction among Dynamic Perfusion Area-Detector CT, Dynamic Perfusion MR Imaging and FDG-PET/CT in Small Cell Lung Cancer Patients with Limited Disease |
1Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 2Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan, 3Canon Medical Systems Corporation, Otawara, Japan, 4Center for Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan, 5Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan |
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No direct comparisons of therapeutic effect prediction have been performed among dynamic perfusion ADCT, dynamic perfusion MRI and FDG-PET/CT in small cell lung cancer (SLCLC) patients. We hypothesize that multiparametric approach by dynamic CE-perfusion ADCT, MRI and FDG-PET/CT can improve therapeutic effect prediction capability in SCLC patients, when compared with each modality assessment. The purpose of this study was to directly compare the capability for therapeutic outcome prediction among dynamics CE-perfusion ADCT and CE-perfusion MRI assessed by same mathematical method and FDG-PET/CT in SCLC patients assessed as limited disease (LD). |
| 4097 | Computer 70
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Comparison of the Capability for Distinguishing Malignant from Benign Pulmonary Nodules among DWI with FASE Sequence at a 3T System, DWIs with EPI Sequence at 1.5T and 3T Systems and FDG-PET/CT |
1Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 2Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan, 3Canon Medical Systems Corporation, Otawara, Japan, 4Center for Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan, 5Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan |
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No one have been compared the capability between DWI obtained by EPI and FASE at 3T or 1.5T systems and PET/CT in this setting. We hypothesized that DWI obtained by FASE sequence at 3T system are more useful than that by EPI sequence at 1.5T and 3T systems and PET/CT for diagnosis of SPN. The purpose of this study was to directly and prospectively compare the quantitative capability for diagnosis of SPN among DWI with FASE and EPI sequences at 3T system, DWI with EPI sequence at 1.5T system and FDG-PET/CT. |
| 4098 | Computer 71
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Whole-Body MRI and PET/MRI at 1.5T and 3T MR System: Comparison of TNM Stage Assessment Capability with PET/CT in Non-Small Cell Carcinoma (NSCLC) |
1Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 2Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan, 3Canon Medical Systems Corporation, Otawara, Japan, 4Center for Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan, 5Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan |
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No one reported direct comparisons for TNM staging capability among whole-body MRI and PET/MRI at 1.5T and 3T systems and PET/CT in NSCLC patients. We hypothesize that whole-body MRI and PET/MRI at 1.5T and 3T MR systems have better potential for TNM stage assessment than whole-body FDG-PET/CT in NSCLC patients. The purpose of this study was to prospectively and directly compare TNM stage classification capability among whole-body MRI and PET/MRI at 1.5 and 3T MR systems and PET/CT in NSCLC patients. |
| 4099 | Computer 72
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Free-Breathing Magnetic Resonance Elastography of the Lung: A Repeatability and Reproducibility Study. |
1Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States, 2Department of Radiology, The Ohio State University, Wexner Medical Center, Columbus, OH, United States, 3MR Application Development, Siemens Healthcare GmbH, Erlangen, Germany |
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Lung stiffness is altered in many diseases making it an important biomarker of understanding lung mechanics. Many patients struggle to hold their breath during scanning due to shortness of breath. We have developed a free-breathing spin-echo-spiral magnetic resonance elastography (MRE) sequence, and a feasibility study was performed on 5 healthy volunteers. It was found that the shear stiffness of the lung during normal breathing was 1.9±0.51kPa and 8.87±1.44kPa with and without considering lung density correction, respectively. Also the measurements were repeatable and reproducible. |
| 4100 | Computer 73
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Half-echo respiratory navigator for motion suppressed 3D ultrashort echo time image for Lung imaging |
1Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of, 2Center for NanoMedicine, Institute for Basic Science (IBS), Seoul, Korea, Republic of, 3Yonsei-IBS Institute, Yonsei University, Seoul, Korea, Republic of, 4Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of, 5Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of, 6Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany |
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In this study, we proposed a new self-gating signal to obtain a high-resolution 3D lung UTE image with suppressed respiratory motion artifacts.This half-echo self-gating (HE-SG) signal can monitor the position of the diaphragm with high spatial and temporal resolution acquired for every TR without any increasing the scan time. Also, this HE-SG can automatically estimate the respiratory motion of the subject so that it can be reconstructed seamlessly for high-quality lung images or time-resolved lung images. |
| 4101 | Computer 74
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Dynamic 3D lung MRI using the stack-of-stars sequence with SI navigation |
1Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2Shanghai United Imaging Healthcare Company, Ltd., Shanghai, China |
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Lung MRI has great potential in clinical early lung cancer screening and staging as it has a high detection rate for pulmonary nodules measuring. However, conventional lung MRI was limited by the physiological motion including respiration and heart beating. In this study, a free-breathing 3D golden-angle radial stack-of-stars pulse sequence with superior-inferior (SI) navigation was proposed for 3D dynamic lung MRI. Lung images in different respiratory stages were obtained. The proposed method provided higher SNR, CNR (between pulmonary vessels and the neighboring background in lung) and fewer motion artifacts than that without SI navigation. |
| 4102 | Computer 75
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UTE-SENCEFUL with a coil clustering algorithm for automatic DC gating |
1Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany |
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In this work UTE-SENCEFUL is combined with a technique for automatic DC gating to produce ventilation weighted maps of the lung in 3D and in high-resolution. |
| 4103 | Computer 76
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Investigating the feasibility of performing quantitative DCE-MRI in an abbreviated breast examination |
1Physics, University of Texas at Austin, Austin, TX, United States, 2Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, United States, 3Biomedical Engineering, University of Texas at Austin, Austin, TX, United States, 4Diagnostic Medicine, University of Texas at Austin, Austin, TX, United States |
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MRI is the most sensitive imaging modality for detecting breast cancer, but its use as a screening tool is limited. There has been recent interest in developing an “abbreviated” breast MRI protocol as a screening protocol, which involves a significantly shorter breast MRI exam that does not compromise diagnostic accuracy. In this work, we evaluate the accuracy of estimating perfusion parameters from dynamic contrast-enhanced MRI data by truncating the data into a series of abbreviated-time courses and comparing the corresponding parameter estimates to the original, full-time course parameter estimates. |
| 4104 | Computer 77
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Quantitative assessment of changes in breast background parenchymal enhancement following tamoxifen treatment |
1Radiology, The University of Chicago, Chicago, IL, United States, 2Radiology, Shiga University of Medical Science, Otsu, Japan |
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Our study introduces a standardizing model of background parenchymal enhancement (BPE) in DCEMRI sequences that can be used to quantitatively and objectively describe changes in BPE rates following preventative tamoxifen treatment. This is in contrast with the current practice of using 4 subjective categories to describe BPE. Decreased BPE rates post-treatment agree with earlier results showing that BPE, like breast density, correlates with breast cancer risk. Standardization for imaging parameters and contrast agent relaxivity increases the observed effect size, giving evidence of increased sensitivity to treatment-induced changes and the potential as a tool for individual breast cancer risk management. |
| 4105 | Computer 78
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Sparse Radial VIBRANT: High Spatiotemporal Resolution Dynamic Contrast Enhanced MRI with Compressed Sensing in Breast |
1Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2GE Healthcare, Waukesha, WI, United States |
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High temporal resolution dynamic contrast enhanced (DCE) MRI is a promising technique for breast cancer detection and diagnosis. We present here Sparse Radial VIBRANT, a high spatial and temporal resolution DCE-MRI method for breast imaging using golden angle radial sampling and temporal compressed sensing, and compare with a view sharing method in breast cancer patients. |
| 4106 | Computer 79
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Classifying HER-2 expression level in breast cancer with types of MRI time-signal intensity curve |
1Department of Radiology, Zhengzhou University People’s Hospital & Henan Provincial People’s Hospital, Zhengzhou, China, 2Medical Imaging School, Mudanjiang Medical University, Mudanjiang, China, 3Cooperative Innovation Center of Internet Healthcare & School of Software and Applied Technology, Zhengzhou University, Zhengzhou, China |
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Breast cancer is one most common cancer in women worldwide. Human epidermal growth factor receptor-2（HER-2）is an important biomarker whose expression status closely relates to the disease outcomes in patients with breast cancer. This study retrospectively explored the difference of MRI time-signal intensity curve types between patients with HER-2 overexpression and patients without HER-2 overexpression. The results indicated the type of washout time-signal intensity curve(TIC) and Non-tumor strengthening is more common in HER-2 amplification or overexpression. The MRI TIC can assess Her-2 status of amplification or overexpression non-invasively before surgery ,and this can help to guide clinician treatment decision and prognosis evaluation. |
| 4107 | Computer 80
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Feasibility of 1 mm isotropic 3D T2-weighted breast imaging accelerated using Compressed SENSE |
1Philips Healthcare, Suzhou, China, 2Philips Healthcare Greater China, Beijing, China |
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We demonstrated the feasibility of 5.3 times acceleration for 3D T2-weighted breast imaging with a 1 mm isotropic resolution at 1.5 T, using Compressed SENSE. This technique showed either better image quality or enhanced imaging speed when compared to traditional SENSE with different imaging schemes. |
| 4108 | Computer 81
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Diagnostic value of intravoxel incoherent motion (IVIM) in benign and malignant breast lesions |
1The Second Hospital of Dalian Medical University, Dalian, China, 2GE Healthcare, Beijing, China |
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In recent years, incoherent motion in voxel has been initially applied to the diagnosis and differential diagnosis of breast lesions. Traditional single-index model DWI can not completely reflect the biological characteristics of tissue diffusion. IVIM bi-exponential model and stretched-exponential model can separate the pseudo-diffusion produced by blood flow in microvessels from the real water molecular diffusion, and accurately evaluate the benign and malignant tumor. This study intends to reflect the characteristics and changes of microstructure in breast tissues at molecular level by quantitative parameters of combined lVIM bi-exponential model and stretched-exponential model, which provides an effective basis for early detection and accurate diagnosis of breast cancer |
| 4109 | Computer 82
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Parenchymal Enhancement in Peritumoral Breast Tissue During DCE-MRI Reflects Response to Neoadjuvant Therapy |
1The University of Texas at Austin, Austin, TX, United States |
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DCE-MRI induced enhancement of fibroglandular parenchyma surrounding breast tumors reflects response to neoadjuvant therapy. Longitudinal MRI performed over the course of NAT demonstrates progressive declines in fibroglandular parenchymal enhancement, with more pronounced declines in patients achieving favorable response to therapy. The degree of parenchymal enhancement is affected by patient age and increases with both tumor enhancement and proximity to the tumor. |
| 4110 | Computer 83
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Clinical Feasibility of Reduced Field-of-View Diffusion-weighted Magnetic Resonance Imaging with Computed Diffusion-weighted Imaging Technique in Breast Cancer Patients |
1Radiology, Dong-A University Hospital, Busan, Korea, Republic of |
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We evaluated the clinical feasibility of the reduced field-of-view diffusion weighted imaging (rFOV DWI) with computed DWI technique in patients with breast cancer by performing a comparison and analysis of the inter-method agreement among the acquired rFOV DWI (rFOVA), rFOV DWI with computed DWI technique (synthetic rFOV DWI; rFOVS), and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in patients with breast cancer. We found that the rFOV DWI and rFOV DWI with computed DWI technique showed nearly equivalent level of image quality required for analysis of the tumors and lesion conspicuity compared with DCE MRI. |
| 4111 | Computer 84
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Simultaneous multi-slice single-shot DWI compared to routine read-out-segmented DWI for evaluation of breast lesions |
1Radiology and Nuclear Medicine, Radboudumc, Nijmegen, Netherlands |
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The aim of this study was to compare a prototype simultaneous multi-slice single-shot echo planar imaging (SMS-ss-DWI-EPI) sequence with conventional readout-segmented echo-planar imaging (rs-DWI-EPI) for diffusion-weighted imaging of the breast at 3T magnetic resonance imaging (MRI). A reader study was conducted to evaluate image quality, lesion conspicuity and BI-RADS® score. Our results show that although the image quality with the conventional rs-DWI-EPI is superior, malignant lesions have improved visibility with the SMS-ss-DWI-EPI sequence. |
| 4112 | Computer 85
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Diffusion-weighted imaging with apparent diffusion coefficient (ADC) mapping in non-mass enhancing breast tumors: influence of region-of-interest placement in diagnostic accuracy and intra-/inter-reader agreement |
1Breast imaging service, Memorial Sloan Kettering Cancer Center, New York, NY, NY, United States, 2Breast imaging, Department of Breast Imaging, Breast Cancer Center TecSalud, ITESM Monterrey, Nuevo Leon, Mexico, Monterrey, Mexico, 3Department of Biomedical Sciences and Morphologic and Functional Imaging, University of Messina, Messina, Italy, Department of Biomedical Sciences and Morphologic and Functional Imaging, University of Messina, Messina, Italy, Messina, Italy, 4Breast imaging service, Memorial Sloan Kettering Cancer Center, New york, NY, United States, 5Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University Vienna, Vienna, Austria, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University Vienna, Vienna, Austria, Viena, Austria |
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Non-mass enhancing (NME) breast tumors are a diagnostic challenge and limited data exists for characterization with DWI with ADC mapping. We aim to investigate the influence of ROI placement and different ADC metrics on diagnostic accuracy of DWI and to assess intra and inter-reader agreement of ADC measurements with DWI in NME breast lesions. Two readers independently assessed DWI using three different ROI´s approaches for ADC measurements. Data indicate that diagnostic accuracy of DWI with ADC mapping is limited in lesions presenting as NME on DCE-MRI with only moderate inter-reader agreement |
| 4113 | Computer 86
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Determine Breast Density from T1-weighted Images using a 3D Convolutional Neural Network |
1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Psychiatry, Stony Brook Medicine, Stony Brook, NY, United States, 3Radiology, Stony Brook Radiology, Stony Brook, NY, United States |
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Using MRI-based breast density (BD) measurements, we trained a convolutional neural network to take a T1-weighted MRI and output a BD value. Our CNN yielded a 3.1% error for the entire data set and 4.1% error in the testing set. Having a CNN work on T1-weighted MRI to quantify BD will allow BD to be a part of every practice. |
| 4114 | Computer 87
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The feasibility of using computerized analysis features of magnetic resonance imaging to predict the outcomes of neoadjuvant chemotherapy for breast cancer |
1RADIOLOGY, PekingUniversity Shenzhen Hospital, SHENZHEN, China, 2RADIOLOGY, PekingUniversity ShenZhen Hospital, SHENZHEN, China |
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This study was based on mathematical calculation software to calculate the imaging features of dynamic enhanced magnetic resonance images(DCE-MRI). The feasibility of outcome prediction of neoadjuvant chemotherapy(NAC) for breast cancer was tested by three kinds of computerized analysis features: morphological features, grayscale statistical features, and texture features. The results indicated that DCE-MRI computerized analysis features before and after 2-cycles of NAC can not predict the degree of pathological remission of breast cancer. DCE-MRI computerized analysis features after 4-cycles of NAC can evaluate the degree of pathological remission of breast cancer. In other words, DCE-MRI computerized analysis features has the potential to be a new noninvasive method of evaluating NAC outcomes. |
| 4115 | Computer 88
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Radiomic Analysis of Breast Cancer Peritumoral Tissue on Contrast Enhanced MRI Prior to Neoadjuvant Chemotherapy |
1Radiology, Brigham and Women's Hospital, Boston, MA, United States, 2Geisel School of Medicine at Dartmouth, Hanover, NH, United States, 3Surgical Planning Laboratory, Brigham and Women's Hospital, Boston, MA, United States |
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This study set out to identify key |
| 4116 | Computer 89
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Adaptation of a Computer Vision Blur Metric to Objectively Compare High Resolution DWI Strategies in in vivo Breast Imaging |
1Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 3Radiology, University of Minnesota, Minneapolis, MN, United States |
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DWI has shown promise for detecting and characterizing breast cancers but is limited by the low spatial resolution of standard spin-echo EPI techniques. Several strategies have been proposed to generate high resolution DWI, including reduced field-of view, steady-state imaging, readout-segmented EPI, and simultaneous multi-slice imaging (SMS). In this work we adopt the Crété-Roffet blur metric to objectively compare resolution of three DWI strategies, including standard SE-EPI, and RO-segmented EPI and SMS-EPI high resolution approaches. In this comparison, both high-resolution DWI methods showed an improvement in in-plane resolution over the standard technique. The Crété-Roffet blur metric appears to be a robust and objective means of comparing effective resolution. |
| 4117 | Computer 90
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Correction of B0 Inhomogeneities-Induced Artifacts in EPI for Breast Imaging |
1Radiology, University of California, San Diego, La Jolla, CA, United States, 2School of Medicine, University of California, San Diego, La Jolla, CA, United States, 3Neuroscience, University of California, San Diego, La Jolla, CA, United States |
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Echo-planar imaging (EPI) is prone to B0 inhomogeneities that arise from susceptiblity effects resulting in spatial distortions more pronounced in the phase-encoded (PE) direction. Reduction and correction of such distortion artifacts are performed in both acquisition and post-processing stages. The present work evaluates the combined effect of a field-of-view (FOV) optimized and constrained undistorted single-shot (FOCUS) EPI and a distortion correction approach to that exploits the symmetry of the artifact on EPI images acquired with opposite PE polarities. After distortion correction good agreement was found between corrected EPI datasets and anatomical images. |
| 4118 | Computer 91
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Feature Engineering for the Subtype Classification of Breast Cancer: A Model Incorporating DCE and DWI Images |
1Shanghai Center for Mathematical Sciences, Shanghai, China, 2ISTBI, Shanghai, China |
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For the 4-IHC classification task, the best accuracy of 78.4% was achieved based on linear discriminant analysis (LDA) or subspace discrimination of assembled learning in conjunction with 25 selected features, and only small dependent emphasis of Kendall-tau-b for sequential features based on the DWI images (DWIsequential) with the LDA model yielding an accuracy of 53.7%. The subspace discriminant of ensembled learning using eight features yielded the highest accuracy of 91.8% for comparing TN to non-TN cancers, and the maximum variance for DWIsequential alone together with a linear support vector machine (SVM) model achieved an accuracy of 83.6%. |
| 4119 | Computer 92
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Semi-automatic ROI registration and texture feature extraction for pre- and post- neoadjuvant chemotherapy contrast-enhanced MR in predicting response of mass-like breast cancers |
1Peking University Cancer Hospital & Institute, Beijing, China |
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In mass-like breast cancers, semi-automatic ROI registration from pre- to post-treatment MR images, and combined with usage of texture feature extraction for automatically segmentation of enhanced areas, the ability for predicting residual tumors after neoadjuvant chemotherapy can be improved significantly and cost lesser time in imaging reading. |
| 4120 | Computer 93
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Focal areas of NME undergoing MRI-guided VABB: outcomes and frequency of malignancy |
1Radiology, Stanford University, Stanford, CA, United States, 2Radiology, St Marianna university school of medicine, Kawasaki, Japan |
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We evaluated the positive predictive values (PPVs) of internal enhancement and kinetic data in focal areas of non-mass enhancement (NME) in patients undergoing MRI-guided vacuum-assisted breast biopsy (MRI-VABB). Our results show the PPVs of clumped and heterogeneous internal enhancement were similar (PPV=25% vs 21%) suggesting that heterogeneous internal is similar to clumped enhancement. The most predictive kinetic pattern of malignancy was fast initial phase without any tendency for cancer using the delayed phase. |
| 4121 | Computer 94
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A comparative study of multi-shot diffusion-weighted imaging (DWI) using multiplexed sensitivity encoding (MUSE) and conventional single-shot echo-planar imaging (EPI) DWI in breast cancer |
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, 2Global Research Organisation, GE Healthcare, Buckinghamshire, United Kingdom, 3Department of Radiology, Addenbrooke's Hospital, Cambridge, United Kingdom |
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MUSE (multiplexed sensitivity encoding) is a multi-shot echo-planar imaging (EPI) technique used in diffusion-weighted imaging (DWI) that reduces distortion and blurring compared to single-shot EPI. Experiments using a breast phantom aimed to investigate the effect of varying parallel acceleration and number of shots on geometric distortion and quantification of the apparent diffusion coefficient (ADC). A refined protocol was applied to a small cohort of patients to comparatively assess improvements in image quality. |
| 4122 | Computer 95
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Threshold isocontouring on high b-value diffusion weighted images in magnetic resonance mammography |
1The Key Laboratory for Interdisciplinary Research, Institute of Biophysics, China Academy of Sciences, Beijing, China, 2Department of Radiology, German Cancer Research Centre (DKFZ), Heidelberg, Germany, 3Medical Physics in Radiology, German Cancer Research Centre (DKFZ), Heidelberg, Germany, 4Radiological Practice at the ATOS Clinic Heidelberg, Heidelberg, Germany, 5Radiology Centre Mannheim, Mannheim, Germany, 6Department of Clinical and Interventional Radiology, University Hospital Heidelberg, Mannheim, Germany, 7Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 8UCSF/UC Berkeley Joint Graduate Group in Bioengineering San Francisco, San Francisco, CA, United States, 9MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Physical and Chemical Sciences, Victoria University of Wellington, Wellington, New Zealand, 10Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany |
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Quantitative evaluation in clinical practice is important for accurate diagnosis, which is often difficult in breast diffusion measurements where large variability of the diffusion metrics is present. Motivated by similar appearance of malignant breast lesions in high b-value diffusion-weighted imaging (DWI) and positron emission tomography (PET), we propose a threshold isocontouring approach commonly used in PET to analyse breast DWI data with minimal inter-observer variability. Our results support that using a relative threshold level of 0.85 almost completely suppresses the intra- and inter-individual variability. This study suggests that the proposed approach is advantageous in the breast DWI data analysis and quantitative evaluation. |
| 4123 | Computer 96
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Identifying metastatic axillary lymph node of breast cancer by quantitative parameters with histogram and texture features on pharmacokinetic modeling dynamic contrast-enhanced MRI: A Pilot Radiomics Study |
1Department of Radiology, Sichuan Cancer Hospital & Institute, Chengdu, China, 2MR Scientific Marketing, Siemens Healthineers, Shanghai, China |
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This study aimed to investigate the discriminative performance of pharmacokinetic quantitative parameters with histogram and texture features on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting axillary lymph nodes metastasis in breast cancer. Results showed that 6 pharmacokinetic quantitative and their histogram parameters,53 texture features of DCE-MRI were statistically difference between the positive and negative group. In cross-validation, the accuracy of the classifier obtained 90% for identifying the metastatic axillary lymph node. The radiomic features based on quantitatively pharmacokinetic DCE-MRI demonstrated promising application in discriminating between metastatic positive and negative axillary nodes of breast cancer. |
| 4124 | Computer 97
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Design of a 3D Printed Patient-Specific Dual Compartment Breast Phantom |
1Bernard and Irene Schwartz Center for Biomedical Imaging and CAI2R, NYU Langone Health, New York, NY, United States |
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Presented here is the design of a 3D printed anthropomorphic breast phantom that includes the key breast tissue compartments which can be filled with desired tissue-mimicking fluids. The breast phantom can be used for validating MRI, coil development, safety evaluation and pulse sequence evaluation. |
| 4125 | Computer 98
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Whole-Tumor Histogram and Textural Analysis of Model-based T2 Mapping for the Ki-67 Labeling Index of Breast Cancer |
1Radiology, Fudan University Shanghai Cancer Center, Shanghai, China, 2Radiology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China, 3MR Application Development, Siemens Shenzhen Magnetic Resonance, Shenzhen, China, 4MR Application Predevelopment, Siemens Healthcare, Erlangen, Germany, 5Advanced Clinical Imaging Technology, Siemens Healthcare AG Switzerland, Lausanne, Switzerland |
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Recently, there has been increased interest in quantitative MR parameters for assessing tumor proliferation. In this study, we proposed the use of whole-tumor histogram texture features using the model-based T2 mapping method GRAPPATINI to differentiate the positive and negative Ki-67 status of breast cancer. Classification performed between Ki-67-positive and Ki-67-negative groups resulted in an area under the ROC curve of 0.808. |
| 4126 | Computer 99
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MRI Staging of Axillary Lymph Node Post Neoadjuvant Chemotherapy Predicts Pathological Complete Response |
1Stony Brook University, Stony Brook, NY, United States |
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This study evaluated a radiological nodal staging metric for accurate identification of diseased axillary lymph nodes (aLNs) on MRI associated with breast cancer. Comparison was made with pathological nodal staging as the ground truth. Radiological scoring of aLNs identifies diseased nodes as suspicious more correctly than it identifies normal nodes as normal. Overall, radiological scoring of the axillary lymph nodes based on morphological characteristics showed moderate accuracy in distinguishing disease or no-disease in the nodes based on standard clinical breast MRI data. Improvement in image signal-noise-ratio (SNR), spatial resolution and contrast of the axillary lymph nodes is needed. |
| 4127 | Computer 101
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R2* decay rates of hyperpolarized dissolved-phase 129Xe as a novel biomarker of fibrotic lung injury |
1Medical Physics, University of Wisconsin, Madison, Madison, WI, United States |
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Spectroscopic imaging of the hyperpolarized xenon-129 dissolved in the pulmonary tissues and blood can probe regional gas exchange within the lung. However, estimates of the frequency shifts and decay rates of the dissolved-phase signal from whole-lung spectroscopy are confounded by the large magnetic field inhomogeneities of the lung. In this work, we develop a regularized, model-based reconstruction that estimates the spectral properties of pulmonary HP 129Xe to improve image quality. Importantly, we show that the estimated r2* decay rates of dissolved-phase compartments differ substantially from those estimated in whole lung spectroscopy and are a significant biomarker of gas-exchange. |
| 4128 | Computer 102
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A magnetic susceptibility model of hyperpolarized 129Xe spectroscopy in alveolar tissues |
1Medical Physics, University of Wisconsin, Madison, Madison, WI, United States |
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Hyperpolarized 129Xe MRI has been used to characterize gas exchange in the lung by measuring xenon dissolved in the red blood cells and pulmonary barrier tissues. However, recent work identified a potential third component of the dissolved-phase spectrum, observed as a splitting of the barrier peak. We propose to explain the appearance of this peak using a signal model that considers the susceptibility differences at the air tissue interface of the alveoli. Integrating this model into whole lung HP 129Xe spectroscopy measures in 8 healthy subjects and 16 patients with idiopathic pulmonary fibrosis, we find improved correlations between the RBC-to-barrier ratio and DLCO %predicted compared to conventional modeling of the dissolved-phase spectrum. |
| 4129 | Computer 103
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Two-site Reproducibility of Hyperpolarized 129Xe MRI Ventilation in Severe Asthma: Implications for Multicenter Clinical Studies |
1Department of Medicine, McMaster University, Hamilton, ON, Canada, 2Firestone Institute for Respiratory Health, St. Joseph’s Healthcare, Hamilton, ON, Canada, 3Robarts Research Institute, Western University, London, ON, Canada, 4Imaging Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada, 5Department of Medical Biophysics, Western University, London, ON, Canada, 6Department of Medicine, Western University, London, ON, Canada, 7Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada |
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Despite the demonstrated sensitivity of hyperpolarized 129Xe MRI biomarkers to pulmonary disease onset, progression and treatment response, comparison of findings across sites is challenging as acquisition protocols and procedures are not standardized. To better understand the agreement of hyperpolarized 129Xe MRI ventilation across different clinical sites, severe asthmatics underwent 129Xe MRI at two sites within 24 hours. 129Xe MRI ventilation defect percent was significantly correlated between sites despite inter-site differences in 129Xe polarization, 129Xe volume, gas mixture composition and signal-to-noise ratio. These findings have important implications when generalizing 129Xe MRI data collected at different sites and undertaking multicenter studies. |
| 4130 | Computer 104
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Absolute MR thermometry by hyperpolarized 129Xe in UCP1-/- animals reveals UCP1-independent thermogenesis |
1Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States |
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Direct and non-invasive temperature measurements of BAT in UCP1-/- mice could help to settle the debate on whether BAT in UCP1-/- mice is thermogenically competent and whether there exist other UCP1-independent mechanisms for non-shivering thermogenesis. Here we use hyperpolarized xenon MR thermometry for direct absolute temperature measurements of brown adipose tissue in UCP1-/- mice. Hyperpolarized xenon MR thermometry indicates a small but detectable temperature increase in the BAT of UCP1-/- mice after adrenergic stimulation of this tissue. |
| 4131 | Computer 105
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Comparison of apparent diffusion coefficient mapping in the lungs of healthy volunteers with 19F C3F8 and hyperpolarized 129Xe gas MRI |
1Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom |
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In this work we derive in-vivo 19F C3F8 and 129Xe apparent diffusion coefficient (ADC) maps from healthy volunteers’ lungs at functional residual capacity (FRC) and total lung capacity (TLC) to evaluate the sensitivity of C3F8 ADC to changes in alveolar dimensions. Each volunteer’s C3F8 ADC values at FRC was significantly smaller than the respective TLC value (P=0.008), and both FRC and TLC values were smaller than the free diffusion coefficient of C3F8. Furthermore, a significant correlation between 129Xe and C3F8 ADC was observed (r=0.69, P=0.029); demonstrating the clinical potential of in-vivo C3F8 ADC mapping. |
| 4132 | Computer 106
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Measuring Septal Wall Thickness Using Rapid 1D Hyperpolarized Xenon-129 CSSR Acquisitions |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States |
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Septal wall thickness measurements using hyperpolarized xenon-129 MRI are sensitive to inflammatory or fibrotic pathologies but currently require multi-second breath-holds. We investigated the feasibility of sampling the recovery of the xenon dissolved-phase magnetization in the lung parenchyma in real time using a rapid 1D acquisition technique combined with periodic saturation of the xenon dissolved-phase magnetization, allowing us to extract the septal wall thickness during short breath holds or even in free-breathing rabbits. Our measurements indicate that the correlation between the derived septal wall thickness and the respiratory cycle are low enough to obtain consistent wall-thickness measurements in free-breathing, non-cooperative subjects. |
| 4133 | Computer 107
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Monitoring of Pulmonary Function in Real-time with 1D Hyperpolarized Xenon-129 MRI |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States |
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Data sampling for pulmonary function measurements using hyperpolarized gas MRI typically lasts for several seconds due to the time requirements for spatial signal encoding. Consequently, highly-dynamic processes are largely invisible to existing lung-imaging techniques. In an initial attempt to observe pulmonary function in real time, we traded spatial resolution for a high temporal resolution of 10 ms by limiting spatial information to 1D projection acquisitions. We tested the technique in a rabbit model by observing pulmonary signal oscillations throughout the lung and by detecting alveolar collapse during expiration at high PEEP in acid-induced acute lung injury. |
| 4134 | Computer 108
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Compressed Sensing Hyperpolarized Noble Gas Ventilation MRI: Towards a Maximum Clinically Acceptable Acceleration Factor |
1Robarts Research Institute, London, ON, Canada, 2Department of Medical Biophysics, Western University, London, ON, Canada, 3Division of Respirology, Department of Medicine, Western University, London, ON, Canada, 4Department of Physics, Ryerson University, Toronto, ON, Canada |
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Compressed sensing has been applied to hyperpolarized gas MRI to accelerate acquisition and allow for increased data or resolution. To better understand the effect of compressed sensing on biomarkers derived from static ventilation images, data were retrospectively undersampled in 10 individuals with chronic obstructive pulmonary disease and k-means clustering was performed. Raw reconstruction resulted in differences less than the ventilation defect percent minimal clinically important difference up to an acceleration factor of 3. The total variation Split-Bregman reconstruction resulted in qualitatively adequate images, however, further optimization of regularized reconstruction techniques is required to achieve consistent ventilation signal clustering. |
| 4135 | Computer 109
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Accelerated Spiral-IDEAL for Gas and Dissolved Phase Hyperpolarized 129Xe in the Lungs of Healthy Human Volunteers: Effect of k-space Calibration Data on Image Quality and Gas Exchange Analysis |
1Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Parallel imaging with multi-channel receivers provides flexible acceleration of scan duration and is an important tool in both clinical and research settings. The application of parallel imaging to hyperpolarized 129Xe MRI may be useful in improving the clinical utility of parametric gas exchange mapping by reducing breath-hold durations or allowing for the acquisition of additional temporal/spatial information. In this work, we investigate the effect of k-space calibration data on parallel imaging reconstruction of time-resolved measurements of hyperpolarized 129Xe uptake using spiral-IDEAL and quantify resultant changes in the estimation of lung physiology. |
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Comparison of hyperpolarised 3He and 129Xe ventilation MRI to assess lung disease in cystic fibrosis |
1POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom, 2Sheffield Children's Hospital NHS Foundation Trust, Sheffield, United Kingdom, 3Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom, 4Respiratory research group, Division of infection, immunity and respiratory medicine, University of Manchester, Manchester, United Kingdom |
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Ventilation MRI using hyperpolarised gases is highly sensitive to early cystic fibrosis lung disease. With the recent move towards 129Xe from 3He, we aimed to assess both gases in parallel in patients with CF, at baseline and follow-up, to determine whether any inherent bias was present when assessing lung disease. We found that there was no inherent bias for VDP between the two gases present although at an individual level differences were evident. Despite this, when followed up at a later date both gases similarly reflected changes in ventilation, suggesting both are capable of reflecting CF lung disease severity. |
| 4137 | Computer 111
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129Xe ventilation and 1H anatomical MRI to detect functional and structural abnormalities in sub-clinical cystic fibrosis lung disease |
1POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom, 2Sheffield Children's Hospital NHS Foundation Trust, Sheffield, United Kingdom, 3Departments of Radiology and Medical Physics, University of Wisconsin, Madison, WI, United States, 4Cardiff University, Cardiff, United Kingdom, 5Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom, 6Respiratory research group, Division of infection, immunity and respiratory medicine, University of Manchester, Manchester, United Kingdom, 7Radiology and Nuclear Medicine department, Erasmus Medical Centre, Rotterdam, Netherlands, 8Paediatric Pulmonology Department, Sophia Children's hospital, Erasmus Medical Centre, Rotterdam, Netherlands |
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Lung MRI in cystic fibrosis (CF) has the potential to measure both structure and function during the same session. Here we assessed 14 patients with CF and normal spirometry for lung abnormalities using 129Xe ventilation and 1H 3D SPGR and UTE anatomical MRI. 129Xe ventilation defects were evident in all subjects assessed, whilst gas trapping was evident on expiratory 3D SPGR in 71% of patients. Further anatomical abnormalities were evident on UTE in 57% of patients. Ventilation and anatomical abnormalities are therefore present in sub-clinical CF and highlights the potential of MRI in routine CF lung imaging. |
| 4138 | Computer 112
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In vivo Validation of Upper Airway Respiratory Computational Fluid Dynamics (CFD) with Phase-Contrast MRI of Hyperpolarized 129Xe |
1Upper Airway Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 2Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 3Departments of Bioengineering and Radiology, University of Missouri, Columbia, MO, United States, 4Division of Biostatistics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 5Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States |
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Computational fluid dynamics (CFD) can provide clinicians with otherwise unobtainable information such as regional airway resistance and breathing effort. However, CFD has yet to be validated in vivo and has only been compared to in vitro experiments that do not represent all aspects of airway physiology. To achieve in vivovalidation, velocities produced by CFD were compared to those measured by phase-contrast MRI of inhaled hyperpolarized 129Xe. Voxelwise comparison of velocities between the two methods produced an R2 value of 0.75 and a slope of 0.91. Phase-contrast MRI produces a benchmark that allows validation and optimization of CFD simulations. |
| 4139 | Computer 113
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Quantifying Hyperpolarized 129Xe Gas Exchange MRI Across Platforms, Field Strength, and Acquisition Parameters |
1Biomedical Engineering, Duke University, Durham, NC, United States, 2Electrical and Computer Engineering, Duke University, Durham, NC, United States, 3Department of Biostatistics & Bioinformatics, Duke University Medical Center, Durham, NC, United States, 4Radiology, Duke University Medical Center, Durham, NC, United States |
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Quantitative analysis of 129Xe gas exchange MRI has previously employed linear binning, using thresholds derived from the mean and standard deviation of a healthy reference population. However, such distributions can be skewed from a purely Gaussian shape by differences in acquisition strategy and field strength, thereby complicating threshold determination. Here we demonstrate a generalization of previous binning methods by applying a Box-Cox transformation to derive non-linearly spaced reference thresholds. We provide new thresholds appropriate for 3T acquisitions and demonstrate the robustness of the approach by showing consistent quantification of subjects scanned longitudinally across platforms, field strengths, and acquisition parameters. |
| 4140 | Computer 114
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The Nature of Early Airway Obstruction in Cystic Fibrosis Lung Disease using UTE MRI and 129Xe MRI |
1University of Missouri, Columbia, MO, United States, 2Center for Pulmonary Imaging Research, Cincinnati Children's Hospital, Cincinnati, OH, United States, 3Radiology, Cincinnati Children's Hospital, Cincinnati, OH, United States, 4Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, OH, United States |
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Cystic Fibrosis (CF) lung disease is characterized by identifiable structural abnormalities on CT or UTE MRI, such as mucus plugs and bronchiectasis. Similarly, hyperpolarized 129Xe MRI can provide functional information related to regional pulmonary ventilation, with high sensitivity to early obstruction. Here we combined UTE and 129Xe MRI to quantify the extent to which specific structural abnormalities contribute to regional ventilation defects. Mucus plugs and bronchiectasis account for the majority of ventilation defects that can be attributed to structural abnormalities. However, structurally-unattributable ventilation defects are more common, implying higher sensitivity than structural imaging to lung dysfunction in milder disease. |
| 4141 | Computer 115
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Mapping and Correcting Hyperpolarized Magnetization Decay Using Radial Keyhole Imaging |
1Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 2Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, NC, United States, 3Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 4Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, United States, 5Department of Pediatrics, University of Cincinnati Medical Center, Cincinnati, OH, United States |
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Hyperpolarized (HP) media enable biomedical imaging applications otherwise unachievable using standard MRI contrast agents. However, quantitative analysis of HP images is complicated by spatially varying signal decay due to T1 relaxation and RF excitation. By imaging with center-out trajectories, HP signal intensity is collected with every acquisition, thereby encoding signal decay alongside k-space data. Using keyhole reconstruction, multiple temporally resolved images were reconstructed to generate voxel-by-voxel maps of hyperpolarized signal decay following a simple analytical model. Here these maps are applied to correct spatially varying magnetization decay in HP 129Xe, improving the quantitative accuracy of ventilation images. |
| 4142 | Computer 116
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Feasibility of Single Breath-hold Isotropic Voxel 129Xe MRI in Patients |
1Robarts Research Institute, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada, 3Division of Respirology, Department of Medicine, Western University, London, ON, Canada |
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Hyperpolarized 129Xe gas MRI has been established as an effective tool to investigate lung function in a number of pulmonary diseases. Improved 129Xe polarization techniques provide the opportunity to use a high-resolution 3D static ventilation image acquisition sequence (FGRE) in a 16-second breath-hold. Isotropic-voxel images were acquired in one healthy-volunteer and two patients with asthma; images were compared to coronal images acquired in two other patients with asthma. Isotropic images had sufficient SNR to analyze VDP. This proof-of-concept investigation establishes the feasibility of using an isotropic-voxel acquisition sequence in single breath-hold MRI of the lungs. |
| 4143 | Computer 117
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Multi-breath Wash-in Hyperpolarized 129Xenon MRI in Human Subjects |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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We have shown the feasibility of multi-breath wash-in imaging of regional fractional ventilation using HP 129Xe MRI for the first time in both healthy and diseased human subjects. |
| 4144 | Computer 118
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The Impact of Echo-time on Hyperpolarized Xenon-129 CSSR Measurements |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States |
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Chemical Shift Saturation Recovery (CSSR) MR spectroscopy and imaging are powerful techniques for deriving a number of important physiological pulmonary parameters. We investigated the impact of measurement echo time on the spectral composition of the acquisition and the subsequent numerical data analysis in rabbits. We found that lengthening the TE resulted in a vastly improved separation between the dissolved-phase resonances by suppressing short T2* signal components. As consequence of this phenomenon, the measured septal wall thickness changed with TE by 1.0 ± 0.13 μm/ms. Similarly, we hypothesize that CSSR-derived measures of pulmonary physiology might be field strength-dependent. |
| 4145 | Computer 119
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Measurement of Regional Fractional Ventilation in a Mouse Model of Lung Cancer under Free-Breathing |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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Hyperpolarized gas MRI is a powerful modality for the assessment of lung structure and function. However, its utility as an investigative tool for animal disease models is limited by the terminal intubation procedures necessary for precise gas delivery and ventilation. Here, we present a technique for measuring regional fractional ventilation longitudinally in a mouse model of lung cancer under spontaneous respiration using hyperpolarized 129Xe MRI. Fractional ventilation maps at different stages of cancer revealed significant structural changes, a decline in regional ventilation, and an increase in ventilation heterogeneities associated with tumor progression. |
| 4146 | Computer 120
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A Technique for Measuring Long-Term Alterations in Pulmonary Gas Uptake under Free-Breathing in a Murine Model of Radiation-Induced Lung Injury |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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Computed tomography (CT), pulmonary function tests (PFT) and positron-emission tomography (PET) are all currently used to assess lung structure and function clinically. However, the sensitivity and safety of these modalities limit their use in cases of progressive lung disease, where longitudinal measurements are of value for both therapeutic planning and monitoring response to treatment. Hyperpolarized 129Xe (HXe) MRI provides robust, specific information about the lungs and is suitable for longitudinal measurements. In this study, we demonstrate an HXe MRI technique for detecting and assessing alterations in pulmonary gas uptake in a mouse model of RILI under spontaneous respiration. |
| 4147 | Computer 121
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Initial Comparison of 19F and Hyperpolarized 129Xenon Gas Lung Imaging in Cystic Fibrosis |
1Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 3UNC/NCSU Joint Department of Biomedical Engineering, Chapel Hill, NC, United States, 4Radiology and Physics, UNC School of Medicine, Chapel Hill, NC, United States, 5Departments of Medicine and Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 6Pulmonary Diseases and Critical Care Medicine, UNC School of Medicine, Chapel Hill, NC, United States |
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Gas enhanced MRI has the potential to provide regional information about lung function that pulmonary function tests alone cannot provide. Hyperpolarized xenon gas is a well-established tool for the assessment of regional lung function in humans, and 19F gas MRI has been proposed as a lower cost alternative that can provide, in addition to ventilation defects, wash in and wash out rates. Here we report the initial findings of a study aiming at comparing these two techniques for assessment of lung ventilation function in subjects with cystic fibrosis. |
| 4148 | Computer 122
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129Xe Gas-Exchange MRI in Pediatrics with Lung Disease |
1Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 2Duke University, Durham, NC, United States, 3Philips, Cincinnati, OH, United States, 4University of Cincinnati, Cincinnati, OH, United States, 5Duke University Medical Center, Durham, NC, United States, 6University of Cincinnati Medical Center, Cincinnati, OH, United States |
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The solubility properties of hyperpolarized 129Xe have made it attractive in many translational pulmonary imaging studies; the large chemical-shift range can be exploited to obtain semi-quantitative ventilation, barrier-uptake, and RBC-transfer images. To date, the technique has demonstrated significant changes in gas exchange in adult lung disease, but has yet to be explored in children, where pulmonary function testing can be more challenging (or impossible). This pediatric gap caused us to pursue 129Xe gas-exchange MRI at the now-common field of 3T; here, we present the first demonstration of dissolved-phase xenon imaging in pediatrics (with cystic fibrosis and post-bone marrow transplant). |
| 4149 | Computer 123
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Xenon-129 MRI of the lung in cystic fibrosis – preliminary results from a clinical trial |
1Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States, 2Medicine, University of Virginia, Charlottesville, VA, United States, 3Public Health, University of Virginia, Charlottesville, VA, United States |
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Results demonstrate sensitivity to early physiologic changes in subjects with cystic fibrosis (CF) using 3D single breath-hold chemical shift imaging (3D-SBCSI). 3D-SBCSI is a technique that uses MRI and hyperpolarized Xenon-129, an inert, non-radioactive gas, to assess lung physiology by detecting Xe-129 in three compartments in the lungs: airspaces, tissue parenchyma and plasma, and red-blood-cells. Results of 3D-SBCSI were compared to pulmonary function test results, Xe-129 ventilation images, blood panels and showed early physiologic trends in mild subjects that progressed on severe CF subjects. 3D-SBCSI could be used to monitor treatment responses and disease progression before symptoms become clinically apparent. |
| 4150 | Computer 124
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Multi-center Comparison of Image Quality Using a Thermally Polarized 129Xe Phantom |
1Biomedical Engineering, Duke University, Durham, NC, United States, 2Center for In Vivo Microscopy, Duke University, Durham, NC, United States, 3Electrical and Computer Engineering, Duke University, Durham, NC, United States, 4Clinical MR Solutions, Brookfield, WI, United States, 5Radiology & Medical Imaging, University of Virginia, Charlottesville, VA, United States, 6Radiology, Duke University Medical Center, Durham, NC, United States |
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Multiple centers are starting to use hyperpolarized 129Xe MR imaging and spectroscopy to quantify pulmonary function. This drives the need for standardization and quality assurance (QA), which is challenging for short-lived hyperpolarized agents. To address this, we developed a high pressure thermal 129Xe phantom constructed from high-density polyethylene and an associated loader shell that mimics the human torso. The phantom was imaged at 8 institutions across North America comprising a variety of scanners, vendors, coils, and field strengths. Image SNR measured with a minute-long scan agreed within a factor of 2 across sites and enabled rapid comparison of MR configurations. |
| 4151 | Computer 126
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Parallel transmit RF safety simulation: effects of differences in tissue compartmentsbetween different voxel models |
1Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Dept of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Oxford Centre for Clinical Magnetic Resonance Research, Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom |
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In this study, we demonstrate the effects on RF simulation from subtly different tissue compartments in the same morphometric space. We evaluate this by using two well-characterised electromagnetic models, Duke versions 1.0 and 3.0. Maps of 10g SAR across a range of B1+ shims were evaluated, showing uncertainties arising from segmentation differences. By using a dedicated voxel model, an increased confidence in electromagnetic simulation can be achieved. |
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Feasibility of personalized RF safety monitoring in pTx MRI using linear registration versus non-linear registration |
1Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Oxford Centre for Clinical Magnetic Resonance Research, Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom |
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In this study, we demonstrate the feasibility of personalised RF safety monitoring in pTx MRI using linear registration versus non-linear registration. We evaluate this by using two well-characterised models, Duke, and MIDA. An 8-channel dipole array was used to evaluate maps of 10g averaged SAR across a range of B1+ shims, showing potential utility of linear registration (rotation, scaling, skew, translation). Our study shows that both linear registration and non-linear registration can be used to monitor SAR in pTx MRI to reduce the safety margin arising from differences in patient head position, shape and size. |
| 4153 | Computer 128
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SAR and temperature distributions in a database of realistic human models for 7T cardiac imaging |
1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2Biomedical Image Processing, Eindhoven University of Technology, Eindhoven, Netherlands |
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A database of 10 realistic human models was generated to study inter-subject local SAR variation for a 7T cardiac coil array. 10 volunteers were scanned at 1.5T after which DIXON imaging data was segmented in five tissue types. SAR and temperature rise were simulated for these models and 10,000 random phase settings. With 99.9% confidence the local SAR levels will not surpass 3.32 W/kg for 8x1 W input power and after 6 minutes of exposure, the maximum temperature rise is 0.19 ⁰C (99.9% confidence). For 20 seconds of exposure (long |
| 4154 | Computer 129
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Assessment of the Alleviating Impact of Perfusion on RF-induced Heating due to Artificial Cardiac Valves |
1Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands, 2Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands |
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Artificial cardiac valves or stents can cause |
| 4155 | Computer 130
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Calculation of the scattered RF field around implants within seconds using a low-rank inverse updating method |
1Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands, 2Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 3Circuits and Systems, TU Delft, Delft, Netherlands, 4Radiology, LUMC, Leiden, Netherlands |
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Scanning patients that have metallic implants may cause tissue heating. This heating is quantified with electromagnetic simulations. We present an alternative method to quickly compute the electromagnetic response of implants by reducing the problem size using a low-rank inverse updating method. This method requires a pre-computed library of field responses at possible implant locations. Results show computed RF fields that are completely equivalent to full-wave simulations while being 1500 times faster. In particular, computations involving small geometric alterations become faster. This method facilitates rapid field computations and possibly enables online RF- or tier 4 ISO/TS 10974 safety assessment. |
| 4156 | Computer 131
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Simplified subject-based models for efficient electromagnetic simulations and evaluation of local SAR for 7 T abdominal MRI |
1SPMIC, Physics, University of Nottingham, Nottingham, United Kingdom, 2University of Nottingham, Nottingham, United Kingdom |
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We investigated the required detail of human body models for Fdtd simulations of a multi-transmit eight-channel body array used for abdominal imaging at UHF. The effect of reducing the number of tissue types on local 10 g averaged SAR (SAR10g,av), B1+ and coil scattering matrices (S-matrices) was investigated on subject-based manually segmented models. Models that differentiate between the lungs, fat, muscle and skin tissue were found to be sufficient to recreate results produced in fully segmented models. This finding was used to implement segmentations of 3 T mDIXON images of subjects to generate subject-specific models for Fdtd simulations efficiently. |
| 4157 | Computer 132
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Repeatability of FDTD simulations for determining local SAR and B1+ distributions for UHF abdominal imaging. |
1SPMIC, Physics, University of Nottingham, Nottingham, United Kingdom, 2University of Nottingham, Nottingham, United Kingdom |
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This study assessed the repeatability of FDTD simulations used to calculate local specific absorption rate (SAR) and B1+ distributions for abdominal imaging on a 7T (UHF) parallel transmit (pTx) system when subjected to typical small displacements of the an eight channel transmit dipole body array experienced when repositioning subjects. Simulations were repeated on two subject-based models and the maximum local 10g averaged SAR (SAR10g,av), B1+ distributions and scattering matrices (S-matrices) were compared to assess variation. The consequences that this has for MR safety, RF shimming and coil loading is discussed. |
| 4158 | Computer 133
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Random RF Shimming may conceal possible local SAR hotspots for asymmetric parallel transmit coils |
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2MR Coils B.V., Zaltbommel, Netherlands, 3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands |
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While general-purpose pTx coils mostly have identical elements arranged symmetrically, coils built for a specific application may be asymmetrical. This asymmetry may lead to a high variation in local SAR distributions of individual coil-elements. For an arterial spin labelling pTx coil, we show that using 2,000,000 unconstrained random excitations to characterize the maximum local-SAR underestimates the local-SAR by 7%. We also show that for the investigated ASL coil, the neck elements, which could be exclusively used for labelling, yield 33% less SAR than the head-imaging coils. Therefore, 50% higher power limits can be used for labelling part of an ASL sequence than the imaging part. |
| 4159 | Computer 134
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An estimation method for maximum local SAR with evaluation points selected by iterative SAR calculation under a restricted random condition |
1Research and Development Center, Canon Medical Systems, Yokohama-shi, Japan, 2Toshiba, Kawasaki, Japan |
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This paper proposes an estimation method for maximum local SAR in parallel transmission. In order to estimate maximum local SAR with fewer evaluation points, the evaluation points are selected by iterative SAR calculation under a restricted random initial input signal condition. It is shown |
| 4160 | Computer 135
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B1+ Peak Based on Transmit Technologies and the Impact of Associated E Fields on AIMD MR RF Safety |
1Abbott, Sunnyvale, CA, United States, 2Abbott, Sylmar, CA, United States |
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Circular polarization (CP), Linear Polarization (LP) and Multi-Channel-N (MC-N) are RF transmit technologies at 3T. The B1+ peak limit is dependent on the RF coil amplifier topology and the transmit scheme. This may lead to significant changes in the induced E field in a patient and affect the MR safety assessment for active implantable medical devices (AIMDs). This abstract shows that even though B1+ peak levels of LP is lower than that of CP or MC-N, the E-field along an implant during LP can exceed CP or MC-N. Therefore, since LP can be achieved within CP or MC-N, it should be considered for AIMD MR safety assessment. |
| 4161 | Computer 136
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Temperature-based MRI safety assessment with a simplified body model |
1Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York, NY, United States, 2Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York, NY, United States, 3Flywheel Exchange, Minneapolis, MN, United States, 4Radiology, Columbia University, New York, NY, United States |
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The shape of the patient affects the distribution of the electromagnetic fields used in MRI. Therefore, it is important to run simulations on body models similar to the shape of the patient. While it was previously shown that a simplified model obtained with automatic segmentation tools could be used to perform a safety assessment based on SAR, we investigate through numerical simulations the possibility to perform temperature-safety assessment with a simplified model. We compare the results obtained with a detailed model comprising 35 tissues, one with 3 tissues (lungs, muscle, fat), and one with 4 tissues (lungs, muscle, fat, skin). |
| 4162 | Computer 137
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The effect of tissue detail in pregnant body models on local SAR prediction accuracy at 3 T |
1Fetal-Neonatal Neuroimaging Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 4Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 5Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 6Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Generating fully detailed electromagnetic body models requires acquisition and segmentation of high-resolution MR images which is particularly difficult in pregnancy due to motion and intolerance of long scan times. However, to explore fetal and maternal RF safety at 3 Tesla with both the standard mode and parallel RF transmission, a variety of pregnant body models are needed. We assess the effects of using simplified versions of 6 pregnant body models on predicting the maternal and fetal peak local SAR. We find that the simplified models under/over-estimate the peak local SAR of fully detailed models by at most 23%/16%. |
| 4163 | Computer 138
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RF heating of an intracranial pressure sensor in a 64 MHz head-only RF coil: a simulation study |
1Physics and Astronomy, University of Western Ontario, London, ON, Canada |
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Heating of implanted medical devices is a well-known hazard in MRI. We evaluated a device which represents an intracranial pressure sensor device, in which a catheter would be inserted into the cranium while the remainder of the catheter and device would be outside the skull, possibly under the skin. The device was modeled as a PEC with a fixed length and was positioned with a variable amount of the lead within the brain and exposure to a 64 MHz head-only RF coil. We found the heating is highest when the amount of the lead within the brain is minimized. |
| 4164 | Computer 139
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RF Safety of EEG gel during MRI: a case study |
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany |
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We evaluated the influences of the EEG gel on RF safety assessment of a 3T whole body scanner with a human subject located at a head landmark position. Our case study, which was performed assuming realistic conditions that may occur with commercially available equipment, provides evidence that the EEG gel “helmet” has an impact on head SAR during 3T MRI for a patient positioned at the head landmark position. A workaround for safe simultaneous EEG-MRI investigations might involve limiting the maximum transmit voltage at a lower level than that allowed by the scanner’s SAR supervision system (i.e. that for a given patient without EEG gel “helmet”). |
| 4165 | Computer 140
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Effect of helix wire geometry and insulator electrical properties on RF-induced temperature rise and the lead electromagnetic model: a case study |
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2U.S. FDA, CDRH, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, MD, United States |
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This case study we investigated RF-induced heating of different helix leads at 127.7 MHz obtained with the lead electromagnetic model (LEM) and direct 3D electromagnetic and thermal co-simulations. A large set of incident electric fields was generated in a phantom by an array of four antennas with varying spatial positions and sources. LEM was validated for predicting temperature in close proximity to the end face of lead tip. However the variance of the fitted values and observed values was rather high for the integral of the power deposition calculated over volume surrounded the lead tip. |
| 4166 | Computer 141
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Ultimate Intrinsic Specific Absorption Rate Efficiency |
1Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey, 3Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 4Industrial Engineering Department, Bilkent University, Ankara, Turkey |
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Peak local specific absorption rate (SAR) is a limiting factor for many high and ultrahigh field MRI applications. Therefore, improving the SAR performance of the transmitters is the scope of many studies. In this study, we used the SAR efficiency (B1+/sqrt(peak local SAR)) as a metric to evaluate the SAR performance of transmitters and investigated its upper bound, defined as Ultimate Intrinsic SAR Efficiency ( |
| 4167 | Computer 142
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Specific Absorption Rate in Head-Only Mid-Field Scanner: Comparisons to 1.5 T and 3 T |
1Physics and Astronomy, University of Western Ontario, London, ON, Canada, 2Synaptive Medical, Toronto, ON, Canada |
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The mid-field system studied here demonstrates reduced maximum 10-g SAR when performing RF excitation around resonant lead lengths as well as a total reduction in SAR consistent with SAR α Bo2. In comparison to 1.5 T and 3 T clinical scanners, mid-field scanners provide unique opportunities to obtain diagnostically relevant information with a commensurate increase in safety for patients with implanted devices. |
| 4168 | Computer 143
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Optimisation and validation of numerical simulation methods for parallel-transmit MRI near a hip implant at 7T |
1School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, 2Siemens Healthcare Pty Ltd, Brisbane, Australia, 3Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia |
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Electromagnetic simulations are commonly used at 7T to predict and limit RF heating when pTx techniques are used. Correction of simulation results based on measured B1-maps and MR thermometry data have been shown to improve the simulation results, but may be affected by the presence of metal implants. In this work, B1-mapping and direct measurement of E-fields are used to validate simulation results of a pTx hip coil in the presence of a hip implant in a phantom. B1-data and/or E-field data were used and compared to correct simulation results. |
| 4169 | Computer 144
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RF heating asymmetry in the implants placed at opposite lateral halves of the ASTM phantom |
1Case Western Reserve University, Cleveland, OH, United States, 2Cleveland Clinic, Cleveland, OH, United States |
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The rectangular shape of ASTM phantom may result into asymmetry in heating when an implant is placed symmetrically on the left and right lateral half of the phantom. In this work, we study the RF induced heating at the tip of a long insulated implant partially immersed into the crown of an ASTM phantom through two opposite lateral halves. The position of the wire on the left and right halves are symmetrical about the central sagittal plane. The results show that the RF heating of an implant is 2-3 times higher at left than at right half of phantom. |
| 4170 | Computer 145
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A Comparison of RF-Induced Heating for a Range of Titanium Rods at 1.5T and 3T |
1Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States, 2Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 3Radiological Sciences Lab, Radiological Sciences, Stanford University, Stanford, CA, United States |
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RF induced heating is a principal concern for patients with active implantable medical devices (AIMDs). MRI exams at >1.5T are often avoided, largely because the SAR increases with the square of field strength, thus RF-induced heating is expected to increase. RF induced heating, however, also arises because of the antennae-like characteristics of the AIMD. Our objective was to compare RF-induced heating in rods with different lengths at 1.5T and 3T when the same B1+RMS was applied. Results suggest that for a specific device length, RF-induced heating is not always higher for increasing field strength. |
| 4171 | Computer 146
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Standardized, Validated and Effective Safety Assessment of Patients with Medical Implants under MRI Exposure Using a Comprehensive Data Library Combined with an Analytics Toolset |
1IT'IS Foundation, Zurich, Switzerland, 2ETHZ, Zurich, Switzerland |
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The radiofrequency (RF) induced heating for patients with implants during exposure to magnetic resonance imaging (MRI) is a complex function of multiple factors, e.g., implant characteristic, patient anatomy, imaging position, RF coil, etc. A comprehensive safety assessment cannot be derived from the limited scenarios possible in clinical trials. We have established an in silico safety assessment trial that comprises a comprehensive data library with a data analytics toolset to perform a complete evaluation in a timely and traceable manner. We demonstrate the workflow for RF-induced heating evaluation for patients with medical implants. |
| 4172 | Computer 147
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Body temperature assessment through deep learning: the Non-Invasive Temperature Estimation (NITE) method |
1Columbia Magnetic Resonance Research Center, Columbia University, New York, NY, United States |
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Heating risks may prevent a patient from receiving an optimal scan. A novel method of internal temperature prediction is proposed by training a neural network on a temperature map from a simulated brain slice, and testing on two other structurally different brain slices. The features are the tissues properties, distance to surface sensors, surface temperatures. The network provides similar maps compared to simulated maps. Current and ongoing work includes optimizing the network parameters to balance the accuracy of predicted temperature with the ability to generalize for the brain anatomy. Future work involves training on two models and testing on others. |
| 4173 | Computer 148
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Impact of different materials along the lead body and at the electrode on temperature rise at the electrode of an active implant |
1Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States |
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Temperature rise, scaled to the square of |
| 4174 | Computer 149
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Individualized SAR Calculations Using Computer-Vision-Based MR Segmentation and a Fast Electromagnetic Solver |
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Dept of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 5Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, United States |
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Current local specific absorption rate (SAR) calculations with offline simulated body models yield conservative safety limits on parallel transmission protocols. By using a personalized medicine approach, whereby the patient-specific body model is generated as the patient lies on the table, more accurate safety limits can be employed. In this study, we developed a fast methodology to scan the patient, segment the body, and calculate the global and local SAR. Our results from multiple volunteer scans show a 30% variation in local SAR, indicating the need for a patient-specific approach. |
| 4175 | Computer 150
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RF-induced heating in the vicinity of human depth intracranial EEG electrodes: effect of electrode and implantation simplification on computational EM simulations |
1Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom, 2Department of Clinical and Experimental Epilepsy, Epilepsy Society, Buckinghamshire, United Kingdom, 3Administration of Medical Physics, King Abdullah Medical City (KAMC), Makkah, Saudi Arabia, 4CIBM-AIT, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 5Department of Biomedical Engineering, King's College London, London, United Kingdom, 6Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 7Wellcome EPSRC Centre for Medical Engineering, King's College London, London, United Kingdom |
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Empirical assessments on phantoms are essential to assess the health risks associated with performing EEG recordings concurrently with fMRI in humans; however they are time consuming limiting our capability to adequately investigate the range of scenarios encountered in real-world applications. Electromagnetic (EM) computational simulations can help to address this limitation, if they can be performed efficiently enough. Here we assessed the improvements of computational efficiency obtained by simplifying the representation of brain-indwelling EEG electrodes for EM simulations. The observed differences in estimated SAR between the full and simplified models can be understood in terms of a simple heuristic model. |
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Computer 151
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Safety of active catheters in MRI: Termination impedance versus RF‐induced heating |
1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2German Cancer Consortium Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany |
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To assess the MR safety of an active catheter, the interaction of an arbitrary E-field with an isolated transmission line was modeled analytically in cascaded lossy media. The catheter tip SAR was calculated for different E field configurations and termination impedances that were controlled by an input impedance unit integrated into the receiver interface circuit. Results of the analytical calculations were compared to transfer function (TF) measurements, and found to be in good agreement. By adjusting the input impedance, SAR at the tip of an active catheter could be reduced by 95%. |
| 4177 | Computer 152
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Initial comparison of RF-induced heating in the ASTM phantom and a cadaver leg: a pilot study |
1The xMR Labs, Department of Physics & Astronomy, Western University, London, ON, Canada, 2Department of Medical Biophysics, Western University, London, ON, Canada, 3Fowler Kennedy Sports Medicine Clinic, Western University, London, ON, Canada, 4Lawson Health Research Institute, London, ON, Canada |
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The current standard for measurement of RF-induced heating for implanted devices is described in ASTM F2182-11a, however this method represents a highly conservative situation (i.e. higher than expected heating). Here we present a pilot cadaveric study investigating the relationship between heating of a standard device (10-cm Ti rod) placed within the ASTM phantom versus a cadaveric leg. At 64 MHz and 128 MHz, the respective implant heating in the cadaver was 1.57 and 9.87 °C, compared to 9.81 and 15.4 °C in the phantom. These results suggest a large margin between heating in the ASTM phantom and heating in-vivo. |
| 4178 | Computer 153
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Mitigating heating risk for long active metallic-backbone or metallic-braided cardiovascular devices using miniaturized Baluns (MBaluns): Design parameters, heating tests, and swine validation |
1School of Medicine, Johns Hopkins University, Baltimore, MD, United States, 2Cincinatti Children’s Hospital Medical Center, Cincinnati, OH, United States, 3Stanford University, Stanford, CA, United States, 4Abbott Laboratories, Minnetonka, MN, United States |
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Long (>wavelength/4) actively-tracked metallic-backbone or metallic-braided cardiovascular devices are not used in MRI-guided interventions due to surrounding-tissue heating concerns. Such devices may be used if induced currents on the metallic-backbone and internal cables are sufficiently attenuated. At ISMRM 2018 we demonstrated a miniaturized resonant floating Balun (MBalun), and two actively-tracked MRI-guided metallic interventional devices built using MBaluns. MBaluns were constructed with loosely-wound solenoids overlaid on the metallic-backbones, generating strong transverse magnetic fields that attenuated surface currents and internal-cable common-mode currents. We now provide electromagnetic simulation revealing MBalun critical dimensions, along with phantom heating and swine experiments that validate the designs. |
| 4179 | Computer 154
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Planning Current Nulling for Worst Case SAR reduction in a Cardiac Guidewire Scenario at 1.5T |
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom |
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Interventional MRI using long conductive guidewires, risks high Local SAR and reduced image quality. This work expands on previous work relating current ‘nulling’ techniques to reducing worst case SAR, by investigating the importance of wire placement and current sensing planning. Results showed that two very distinct wires displayed common features but differences in behaviour do not allow for a generic ‘nulling’ plan. Also, there is a trade-off between removing current-generating modes, and reducing B1+ efficiency that subsequently increases RF power to achieve necessary image quality. Overall, a careful study of the system can help find the optimal ‘nulling’ plan. |
| 4180 | Computer 155
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Concurrent scalp and intracranial electroencephalography recording in a human 1.5T MRI scanner: RF-induced heating assessment |
1Department of Clinical and Experimental Epilepsy, University College London, London, United Kingdom, 2Department of Clinical and Experimental Epilepsy, Epilepsy Society, Buckinghamshire, United Kingdom, 3Administration of Medical Physics, King Abdullah Medical City (KAMC), Makkah, Saudi Arabia, 4Lysholm Department of Neuroradiology, UCLH NHS Trust, London, United Kingdom, 5Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom, 6Department of Experimental Epilepsy, National Hospital for Neurology and Neurosurgery, London, United Kingdom, 7Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 8Wellcome EPSRC Centre for Medical Engineering, King's College London, London, United Kingdom |
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The acquisition of electroencephalography (EEG) concurrently with functional magnetic resonance imaging (fMRI) requires careful consideration of the health hazards resulting from interactions between the scanner’s electromagnetic fields and EEG recording equipment. with excessive RF-induced heating near the electrodes being the main one. In view of performing concurrent scalp and intracranial EEG-MRI, we measured heating in the vicinity of electrodes placed within and on a phantom during high-SAR sequences in two conditions: with intracranial electrodes only, and following the addition of scalp electrodes. Temperature variations were well within the safety guidelines at all measurement locations in both conditions. |
| 4181 | Computer 156
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Parallel RF Transmission for Safe 3 T MRI of Deep Brain Stimulation Devices: Effect of Mis-positioned Suppression Mode |
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Magnetic resonance imaging (MRI) offers many benefits for deep brain stimulation (DBS) patients. However, radiofrequency (RF) heating remains a concern for MRI at 3T. Parallel transmission technology (pTx) has the potential to lower the risk by generating low electric-field regions at target locations. As pTx technology proceeds to imaging DBS patient, the impact of head motion becomes an important consideration. The present study investigates the impact of phantom mis-positioning when using pTx technology to suppress RF heating with results indicating head motion can potentially cause unsafe temperature elevations. |
| 4182 | Computer 157
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Determination of local SAR through MR Thermometry at 7T |
1Siemens Healthineers, Erlangen, Germany, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Radiology, Harvard Medical School, Boston, MA, United States |
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MR thermometry at 7T allows the straight forward acquisition of temperature maps with very high spatio-temporal resolution. This sensitive method at ultra high fields (UHF) allows the acquisition of local SAR distribution in a tissue equivalent gel head phantom. Using a 1mm isotropic resolution, 5s sampling rate and <0.04°C accuracy in temperature we are able to assess the MR safety of RF coils and validate the underlying electromagnetic and thermal simulations. |
| 4183 | Computer 158
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Comparison of Simulated and Robotically Mapped RF Fields in 64 and 128 MHz Medical Implant Test Systems |
1The xMR Labs, Department of Physics and Astronomy, Western University, London, ON, Canada |
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In this work we demonstrate a procedure for the use of a custom-built, semi-automated robotic positioning system to map EM fields in commercially available RF exposure systems and compare the results against FDTD simulations. All field measurements were obtained independently with calibrated E-field or H-field probes. Results show that the robot can effectively operate within the complicated EM environment of the RF exposure platforms with good agreement between simulated and measured results. Future work will continue to improve the techniques discussed here. |
| 4184 | Computer 159
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Safety Assessments in the Cascaded Media Using an Electro-optic Sensor-based Transfer Function Measurement Setup |
1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2German Cancer Consortium Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3Institute of Photonics and ICT (IPI), University of Applied Sciences HTW Chur, Chur, Switzerland |
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MR safety evaluations of metallic implants/devices are performed in single homogeneous media. However, most of the implants/devices function in different media interfaces such as DBS and iEEG electrodes, catheters, biopsy needles…, etc. Loading of the conducting lines change drastically inside media with different dielectric properties, so does the RF-induced heating characteristics. To improve in vitro MR safety evaluations, we introduce a new TF measurement setup that allows safety evaluations in cascaded media (CM). The performance of the CM-TF setup was verified on isolated and bare lead wires immersed in air/tissue-simulating-medium interface by comparing to FDTD simulations and analytical models. |
| 4185 | Computer 160
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Avoiding Systematic Errors of Fiber-optic Temperature Probes: MR Thermometry for Safety Assessment of Small Planar Metallic Structures |
1Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Department of Microsystems Engineering - IMTEK, University of Freiburg, Freiburg, Germany, 3BrainLinks-BrainTools, Freiburg, Germany, 4German Cancer Consortium Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany, 5CorTec GmbH, Freiburg, Germany |
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Patients with AMIDs are exposed to a significant safety hazard during MRI, as the RF excitation couples to the elongated metallic structures of the AIMD resulting in an unwanted heating of tissue. Temperature measurements are the standard method for heating tests of implants to ensure patient safety during MRI exams. Temperature sensors with a significant size compared to the samples influence the RF absorption of energy and can distort the temperature distribution. MR thermometry can provide a non-invasive 2D alternative. |
| 4186 | Computer 161
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Repeatability of measured RF transfer functions of IPG and lead based AIMD systems |
1Boston Scientific, Valencia, CA, United States |
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Lead heating and malfunction of implantable medical devices, such as Spinal Cord or Deep Brain Stimulators, due to MRI RF field exposure are patient safety concerns. The transfer function is a method used to calculate predictions of MRI-induced heating or injection voltages. This study investigated the repeatability of a measurement-based transfer function system. Results showed that the inherent variation of the system can be minimal, whereas lead positioning in the system has a higher impact on variation. |
| 4187 | Computer 162
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Superadditive RF Heating in Gaps between Two Metallic Implants |
1IT'IS Foundation, Zurich, Switzerland, 2Swiss Federal Institute of Technology (ETH), Zurich, Switzerland |
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The test method for safety assessment with regard to radiofrequency (RF) heating of small metallic medical implants in MRI is standardized by ASTM. However, the focus lies on individual or electrically connected implant systems whereas, the none-electrically connected combination of multiple adjacent implants has not yet been sufficiently investigated and may lead to considerably altered RF coupling. In this study, we assessed induced heating as a function of the separation distance between two orthopedic metallic implants. Results show that the strong coupling between two short implants may lead to even higher temperature increases than that of a single implant of the combined length. |
| 4188 | Computer 163
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Radiofrequency Heating of MR-conditional Needles during Interventional Magnetic Resonance Imaging at 1.5 and 3 Tesla Field Strengths |
1Department of Radiology, Musculoskeletal Imaging, New York University School of Medicine, New York, NY, United States, 2Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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MR conditional 10, 15 and 20 cm cobalt chromium needles pose minimal risk of thermal injury when placed at a 45° to 90° angle relative to the patient table even after 5 minutes of continuous imaging with interventional pulse sequences (< 2.5 ˚C temperature rise). Higher temperature rises of up to 8˚C (3T) and 22˚C (1.5T) occur when needles are oriented parallel to the static magnetic field. If the needle must be placed in such orientation, low Specific Absorption Rate pulse sequences and needle lengths that differ substantially from half of the radiofrequency pulse wavelength should be used. |
| 4189 | Computer 164
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Compact 3T MRI for imaging patients with implanted devices: RF and SAR consideration |
1Radiology, Mayo Clinic, Rochester, MN, United States, 2GE Global Research, Niskayuna, NY, United States |
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Patients with certain implanted devices have been restricted from MRI exams with the whole-body transmit coil due to concern of local heating. A novel compact 3T (C3T) MRI scanner is equipped with an RF coil of larger radius but similar length as a T/R head coil. The purpose of this work is to assess the RF B1 field and E-field of the C3T T/R coil. RF heating risk of head imaging on C3T for patients with implanted devices was evaluated and compared with a commercial T/R head coil. |
| 4190 | Computer 165
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Retrospective evaluation of the maximum MR image artifact size according to ASTM F2119 with respect to sequences and slice orientations relevant for MR compatibility testing |
1MR:comp GmbH, Gelsenkirchen, Germany, 2Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Essen, Germany, 3High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 4MRI-STaR-Magnetic Resonance Institute for Safety, Technology and Research GmbH, Gelsenkirchen, Germany |
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This study examines the influence of sequence type, slice orientation and test object orientation on artifact size for medical implants. For this purpose, 79 different objects were evaluated according to ASTM F2119 and the influence of the different parameters was investigated. The evaluation shows that gradient echo sequences more often represented the worst case MR image artifact size as compared to the corresponding spin echo sequences. In addition to this result, the sagittal slice orientation, as compared to the transversal slice orientation, was shown to produce the worst case MR image artifact. |
| 4191 | Computer 166
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Influence of the Electrode Diameter on Radio Frequency-induced Heating in MRI |
1University of Freiburg, Freiburg, Germany, 2University Medical Center Freiburg, Freiburg, Germany, 3University of California Los Angles, Los Angeles, CA, United States, 4CorTec, Freiburg, Germany, 5Dep. of Microsystems Engineering, University of Freiburg, Freiburg, Germany, 6Stanford University, Stanford, CA, United States |
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Patients with implanted electrodes often require an MRI exam. This exposes them to the risk of radio-frequency induced heating. In this study heating of implantable electrodes of diameters between 0.3-4mm were evaluated in a 1.5T MRI system. In situ temperature measurements were compared to simulations of the specific absorption rate to assess local and total dissipated power. Measurements showed temperature increases between 0.8-53K. Compared to large electrodes, small electrodes are subject to less dissipated power, but more localized power density. Thus, smaller electrodes might be classified as safe in current certification procedures but may be more likely to burn tissue. |
| 4192 | Computer 167
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On the RF Excitation of Overlapping Stents: Electro-optical E-field Measurements |
1Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Institute of Photonics and ICT (IPI), University of Applied Sciences HTW Chur, Chur, Switzerland |
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In stents, RF-induced heating is mainly associated with the antenna effect that occurs due to the thin and elongated geometry. Heating occurs mainly at the stent tip where a dipole-like E-field pattern is present. However, the E-field pattern and thus the locations of maximum heating change when two stents overlap. Using an optical setup for high-resolution E-field mapping, we provide further insight in the RF excitation of various combinations of stents in different geometric and dielectric configurations. |
| 4193 | Computer 168
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Verification and validation of a dB/dt exposure system using a robotic positioning system and induction field probe. |
1The xMR Labs, Physics and Astronomy, Western University, London, ON, Canada |
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In this abstract a semi-automated verification and validation protocol for a dB/dt system are presented. A dB/dt coil was simulated, fabricated, and mapped with both a hall probe and dB/dt probe using a positioning robot. All measured values, both DC and dB/dt, matched the expected values over the exposure volume. In addition, dB/dt measurements in air and in saline verify the consistency of the magnetic field in a typical device testing media. |
| 4194 | Computer 169
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Comparison of Device Vibration Induced by Trapezoidal and Sinusoidal Gradient Waveforms |
1The xMR Labs, Physics and Astronomy, Western University, London, ON, Canada |
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Gradient induced vibration of a steel disk due to trapezoidal and sinusoidal gradient waveforms was measured at varying frequencies at 3 T. Results show displacement increased monotonically with decreasing frequency but peak acceleration, scaled to the peak gradient field, remained consistent for all experimental conditions. Sinusoidal dB/dt exposure as a function of frequency represents a practical conservative exposure condition for testing dB/dt-induced vibration in conductive devices during MRI. |
| 4195 | Computer 170
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Spoiler, Crusher, and Diffusion Gradient Pulses Yield Higher PNS Thresholds than Long Pulse Trains in Head-only Gradient Coils |
1xMR Lab, Physics & Astronomy, The University of Western Ontario, London, ON, Canada |
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Gradient-induced peripheral nerve stimulation remains a major performance limitation in MRI. Imaging sequences are limited to experimentally-determined thresholds that reduce the likelihood of uncomfortable stimulation in patients, typically using long bipolar trapezoid trains or sinusoidal waveforms. However, common short waveforms found in pulse sequences such as spoilers, crushers, and diffusion pulses could be optimized for higher thresholds. 20 subjects were exposed to representative waveforms for each of these pulse sequences and resulting thresholds indicate that gradient performance increases of between 20 and 40% may be possible. |
| 4196 | Computer 171
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The effect of spatial averaging on dB/dt exposure values for implanted medical devices |
1The xMR Labs, Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada |
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We address to what extent the peak dB/dt exposure for active implantable medical devices (AIMDs) desbribed in ISO 10974:2018(E) differs from the spatial average of dB/dt values for devices relevant for testing with realistic spatial extent. |
| 4197 | Computer 172
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Compact 3T MRI for imaging patients with implanted devices: Maximum gradient slew rate considerations |
1Radiology, Mayo Clinic, Rochester, MN, United States, 2GE Global Research, Niskayuna, NY, United States |
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Some implanted devices are labeled as “MR conditional.” Depending on the specific conditions, a desired exam may be precluded, or only allowable under suboptimal conditions. For example, there may be limitations on the gradient slew rate or static field, which are more stringent than the standard regulatory limits in the absence of the implant. Recently, compact 3T (C3T) MR was introduced with high-performance gradients. It is shown that for brain imaging, the safety conditions for some implants may be satisfied at the location of the implant, while the full imaging performance of the C3T is available to image the brain. |
| 4198 | Computer 173
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Control of Gradient Output for Limiting AIMD Gradient Induced Device Heating |
1Abbott, Sylmar, CA, United States, 2Abbott, Sunnyvale, CA, United States |
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Control of imaging gradient |dB/dt| rms is desired to limit potential gradient induced heating of medical implants. Current controls for |dB/dt| rms have been implemented on a per sequence basis. In this abstract we show that controlling gradient |dB/dt| rms on a per sequence basis may be overly conservative for certain examinations containing sequences with transient durations of high |dB/dt| rms. As such there is the potential to unnecessarily restrict clinical sequences with acceptable device heating. Alternative means for controlling |dB/dt| rms, such as calculating |dB/dt| rms using a rolling average across sequences, should therefore be considered. |
| 4199 | Computer 174
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Neurostimulation Safety Investigations using Reference, Posable Anatomical Models |
1Foundation for Information Technology in Society, Zurich, Switzerland, 2Max Plank Institute, Tuebingen, Germany, 3Swiss Federal Institute of Technology (ETHZ), Zurich, Switzerland |
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Investigations about the risk of Peripheral Nerve Stimulation (PNS) in magnetic resonance imaging (MRI) are fundamental to mitigate potential safety issues related to the new generation of MRI scanners that use larger Larmor fields and faster/higher gradients. In this study we evaluate the potential of in silico studies for determining the thresholds of PNS when taking into account the anatomical detail and electrophysiology of the peripheral nervous system. We used the latest hybrid electromagnetic (EM) and neuronal simulators combined with our recently released neuro-functionalized Virtual Population model Yoon-sun V4.0. The vision is to utilize such systems for pulse sequence optimization to reduce PNS, the revision of low frequency exposure guidelines, etc.. |
| 4200 | Computer 175
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Gradient dB/dt Heating Measurements of Copper, Steel, and Titanium Annuli: Assessment of Measurement Repeatability, and Identification of a Potential Reference Standard |
1Physics and Astronomy, University of Western Ontario, London, ON, Canada |
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The purpose of this work is to develop a simple reference standard to be used for gradient-induced heating tests to verify test system operation. A second objective is to provide data on measurement repeatability of heating in these reference objects. Two different dB/dt exposures (270 Hz and 1000 Hz) were used to measure the gradient-induced temperature rise of three MRI compatible metals using a laboratory dB/dt exposure system. Based on the temperature rise, an MRI compatible metal of distinct dimensions and geometry was determined to be most suitable as a dB/dt heating standard across a frequency range of 270-1000 Hz. |
| 4201 | Computer 1
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Sodium MR Imaging of Porcine Articular Cartilage on a Whole-body 10.5T MR System – Initial Results |
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 3Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States, 4Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, United States |
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New advancements in ultrahigh-field human whole body 10.5T MR imaging hold potential for improvements in sodium imaging of articular cartilage. We investigated optimal imaging parameters and image quality for the evaluation of sodium concentrations in porcine articular cartilage using a 3D-UTE sequence and birdcage sodium knee coil at 10.5T. The mean sodium concentrations in femoral and patellar cartilage of a porcine stifle joint were 298 and 307 mM/L, respectively. These values are in good agreement with previously-published concentrations. Our findings support the feasibility of sodium imaging of articular cartilage at 10.5T and motivate future in vivo studies. |
| 4202 | Computer 2
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Non-invasive assessment of myocardial cell viability based on 23Na triple-quantum signal |
1Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 2Department for Molecular Cardiology and Epigenetics, Heidelberg University, Heidelberg, Germany, 3Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany |
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Sodium MRI was proposed in addition to cardiovascular magnetic resonance methods to detect viable cells. In this work, a spectroscopic sequence with time proportional phase increments was used to measure single- and triple quantum coherences of the spin 3/2 sodium nuclei simultaneously. We investigated the sodium triple-quantum signal of cardiomyocytes in an MR compatible bioreactor to gain further understanding of the TQ signal of cardiomyocytes under stimulation. This setup may be applied in the future to simulate additional diseases as well as potentially monitor the single-quantum and triple-quantum signal changes, e.g. in hypertrophy and after myocardial infarction in-vivo. |
| 4203 | Computer 3
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31P Single Voxel MRS in the Human Brain at 9.4T: ISIS versus SemiLASER |
1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria |
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In vivo phosphorus MR spectroscopy has been established to be a powerful tool for studies of energy metabolism. To provide clinically relevant information about physiologic function, accurate spatial localization as well as sufficient spectral quality are fundamental requirements. Therefore, in this study, first steps to optimize a multi-shot ISIS sequence and a single-shot semiLASER sequence for phosphorus MR spectroscopy in the human brain at 9.4T have been taken. The sequences were compared in terms of localization accuracy and SNR. |
| 4204 | Computer 4
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Ultrahigh Field (14.1 Tesla) 1H/23Na MRI of the Rat Tail In Vivo: A Comparison Study |
1Biomedical and Mechanical Engineering, The Pennsylvania State University, State College, PA, United States, 2State College High School, State College, PA, United States, 3Biomedical Engineering, The Pennsylvania State University, State College, PA, United States |
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This study verified the ability to acquire high resolution sodium and proton MR images of rat tail intervertebral discs in vivo. Utilizing the hardware developed in a previous study, female Fischer 344 rats were imaged in vivo. Resolutions of 78um isotropic and 500um isotropic were achieved for proton and sodium images respectively prior to zerofilling. Comparisons between in vivo and ex vivo images showed similar anatomical and biochemical results. However, slight differences in the sodium images were observed. Sodium concentration was estimated using blood in the ventral tail artery as a reference. |
| 4205 | Computer 5
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B0 shimming for X-nuclei imaging at 7 T using 23Na B0 maps |
1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 3Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 4Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany |
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B0 inhomogeneities are a major challenge at ultra-high magnetic field strengths (B0 ≥ 7 T), as they can lead to strong image artifacts. In this work, a B0 shimming routine that is based on 23Na B0 maps was implemented for applications in X-nuclei imaging where no 1H MRI data can be acquired and therefore, no vendor-provided shimming routines can be used. The proposed 23Na ConsTru shimming routine showed an improvement in B0 homogeneity comparable to the vendor-provided GRE Brain shimming routine both in phantom and in vivo measurements using 23Na B0 map acquisition times less than 1 minute. |
| 4206 | Computer 6
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Oxygen-17 MRI Reveals Unchanged Cerebral Metabolic Rate in Aquaporin-4 Knockout Mice |
1Radiology, Case Western Reserve University, Cleveland, OH, United States, 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Neurology, Case Western Reserve University, Cleveland, OH, United States, 4Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States |
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This study aimed at investigating the role of aquaporin-4 (AQP-4)-facilitated gas transport in regulating cerebral metabolism. Cerebral metabolic rate of oxygen (CMRO2) was quantified in AQP-4 knockout and wildtype control mice using oxygen-17 (17O) MRI. Our results showed no change in CMRO2 in AQP-4 knockout mice, suggesting that AQP4-facilitated gas transport is not a rate-limiting factor in cerebral metabolism in anesthetized mice. |
| 4207 | Computer 7
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Comparison of anisotropic UTE sequences for 23Na/39K imaging in the human calf at 7T |
1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 3Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany |
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Anisotropically scalable UTE sequences enable a higher in-plane resolution for X-nuclei imaging. In this work, a density-adapted 3D radial cuboid acquisition scheme is compared theoretically and experimentally against a 3D acquisition-weighted density-adapted stack-of-stars (AWSOSt) design. For the use case of 23Na/39K imaging in the human calf at 7T, it was found that, when driven at similar and clinically feasible measurement times, the AWSOSt approach provides an increased SNR at the same effective resolution. Potential T2 blurring due to the additional phase encoding had no significant effect in this study. For both sequences a good suitability for anisotropic X-nuclei MR imaging in muscular tissue was confirmed. |
| 4208 | Computer 8
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In vivo study of cerebral NAD contents and Redox State during mouse brain development. |
1Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Prilly, Switzerland, 2Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3HES-SO, University of Applied Sciences of Western Switzerland, HEIA-FR, Institute of Chemical Technology, Fribourg, Switzerland |
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Nicotinamide adenine dinucleotide (NAD+ and NADH) is a key player of cell energy metabolism. 31P-MRS has been demonstrated for in vivo measurement of NAD content and redox state in cat and human brain. We previously demonstrated the feasibility of NAD measurement in mouse brain, and actually we established the in vivo profile of cerebral NAD+, NADH and NAD+/NADH at different ages. This study demonstrated also the feasibility of in vivo measurement of NAD+, NADH and redox state from 20 to 250 days old animals and it opens widely the prospect of studying longitudinally the energy metabolism and redox dysfunction in mouse models of brain pathologies. |
| 4209 | Computer 9
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Fluorine-19 Magnetic Resonance Thermometry: Temperature Dependence of Spin-Lattice and Spin-Spin-Relaxation Times of Fluorinated Drugs at 9.4 T |
1Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany, 2Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany |
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Fluorine-19 (19F) magnetic resonance is a powerful tool for tracking fluorine labelled markers, cells and drugs. Here, we studied the influence of temperature on the 19F MR characteristics (chemical shift, T1, T2, SNR) of four fluorinated drugs using 19F MR mapping and spectroscopy techniques. We demonstrated the impact of temperature on the T1 relaxation time of PFCE nanoparticles in vivo and postmortem. Our findings open a trajectory toward 19F MR-based thermometry and indicate the need for adapting MR sequence parameters according to temperature induced environmental changes. This will be an essential requirement for monitoring fluorinated compounds by 19F MR techniques in vivo. |
| 4210 | Computer 10
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Neuronal energy metabolism in the mouse brain measured by 1H-[13C] MRS at 14.1T under [3-13C]-Lactate infusion: a feasibility study |
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 3Faculty of Medicine, University of Geneva, Geneva, Switzerland |
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In this study, the feasibility of studying neuronal energy metabolism in the mouse brain in vivo under [3-13C]-Lactate infusion, measured by 1H-[13C] MRS at high magnetic field was evaluated. Brain tissue [3-13C]-Lactate enrichment and the turnover of its metabolic products were measured dynamically. Glutamate and glutamine C4 as well as glutamate+glutamine C3 were used as input to a one-compartment metabolic model of the neuronal TCA cycle and glutamate-glutamine cycle, enabling a comparison with previously reported values of metabolic fluxes in the mouse brain under infusion of other labeled substrates. |
| 4211 | Computer 11
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Comparison of human cardiac 31P-MRS on 3 T Trio and Prisma scanners |
1OCMR, RDM Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom, 2Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, 3Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia |
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Cardiac PCr/ATP ratios measured by 31P MRS are a measure of the biochemical “energy reserve” in the heart. They decrease early in the progression of a wide range of diseases, making them a valuable biomarker. Logistically, it is often important for a long-running study to be able to compare data acquired on different MRI scanners. In this study, we show that comparable results may be acquired with 3T Prisma and 3T Trio scanners by scanning 10 healthy volunteers with 31P-CSI and 31P-DRESS on both systems. It is legitimate to pool 3T Prisma and 3T Trio data for clinical studies. |
| 4212 | Computer 12
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Preliminary investigation into the effect of diuretic treatment on in vivo skin sodium using ultra-short echo time 23Na MRI at 3T with biopsy validation |
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, 2Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, 3Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, United Kingdom, 4Department of Radiology, Addenbrooke's Hospital NHS Foundation Trust, Cambridge, United Kingdom, 5GE Healthcare, Munich, Germany |
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In this ongoing study, we investigate the changes in skin sodium concentration between controls and a group receiving a diuretic for seven days and present results from an interim analysis. Ultra-short echo time 23Na-MRI is performed at baseline and after seven days, at the end treatment. Results are correlated with measurements of sodium from biopsy samples. |
| 4213 | Computer 13
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Sodium MRI allows detecting an enhanced sodium concentration in muscles of volunteers following a high salt diet |
1Service of Nephrology and Hypertension, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland |
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The presented study shows by the mean of sodium MRI that the sodium content of the leg muscles of healthy volunteers is higher when following a high salt diet than when following a low salt diet. To our knowledge, this is the first study reporting that fact. |
| 4214 | Computer 14
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Longitudinal heterogeneity of post-exercise perfusion, T2*-weighted MRI and high-energy phosphate metabolism in human calf muscle quantified by interleaved multislice 1H MRI and multivoxel 31P MRS at 7T |
1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 2MR Center of Excellence, Medical University of Vienna, Vienna, Austria, 3Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 4Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria, 5NMR Laboratory, Institute of Myology, Paris, France |
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Multivoxel 31P semi-LASER was used to acquire time-resolved spectra from two positions along the gastrocnemius medialis muscle during rest, exercise and recovery. Simultaneously, quantitative perfusion- and T2*-weighted images of the calf were acquired with multislice 1H ASL MRI, in an interleaved fashion. Significantly different results were found with 31P MRS along gastrocnemius medialis: proximally, end-exercise PCr depletion was higher, PCr recovery times longer, end-exercise pH was lower and maximum oxidative capacity was also lower. Significantly higher post-exercise perfusion and slightly stronger T2*-weighted signal increase were found in proximal slices, which is consistent with the aforementioned distribution of metabolic activity. |
| 4215 | Computer 15
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Metabolic Brain Tumor Analysis: Correlation between ADC/ CBV and quantitative CMRO2 employing dynamic 17O MRI |
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3Institute of Radiology, University Hospital Erlangen, Erlangen, Germany |
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Dynamic 17O-MRI enables a direct measurement of the cerebral metabolic rate of oxygen (CMRO2). Decreased CMRO2 in tumor tissue indicates a change in the metabolic pathway and therefore metabolic imaging can be used as a diagnostic parameter. Data of three high grade tumor patients where investigated with regard to cerebral blood volume (CBV) hyper-intense and apparent diffusion coefficient (ADC) hypo-intense areas to exclude bias of perfusion and ADC. No significant change in CBV+ and ADC- volumes demonstrates the independence of tissue perfusion and cellular density of utilized method and underline the capability of fully quantitative metabolic imaging. |
| 4216 | Computer 16
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Multiparametric statistical quantification of the heterogeneity of free Na+ concentration by 19F NMR spectroscopy |
1CRMBM, Aix Marseille University, Marseille, France |
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Sodium(I) (Na+) plays a key role in basic cell function. Noninvasive methods for measuring intracellular Na+ concentrations ([Na+]i) in biological tissue have been developed on the basis of 19F NMR spectroscopy. By contrast, 23Na MRI at most provides approximate (relative) contributions of intracellular Na+ to total 23Na by relying on a number of theoretical assumptions, as it does not detect Na+i selectively. Since [Na+]i values are often not uniform throughout a given tissue volume (or voxel), we have designed an approach for quantifying total [Na+]i heterogeneity by exploiting the lineshape of the 19F resonance of an appropriate [Na+]i reporter molecule. |
| 4217 | Computer 17
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Novel chemosensory application of 1H and 13C NMR metabolomics in medicinal plants of nutritional value |
1Department of NMR, All India Institute of Medical Sciences, New Delhi, India |
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With increasing incidences of diet and nutrition related diseases, objective evaluation of the chemosensory property of taste has gained significance. In this study, aqueous extracts of select medicinal plants of nutritional value (n=72) from five chemosensory groups were studied using proton and carbon NMR spectroscopy. Partial Least Square Discriminant Analysis of 1H and 13C spectral data have shown chemosensory based differentiation. Examples of targeted metabolomics aided identification of chemosensory markers are: β-glucose (sweet), phenylalanine (bitter), gallic acid (astringent) and citric acid (sour). NMR phytometabolomics can be used as a magnetic tongue in deciphering the role chemosensory phytomarkers in nutrition science. |
| 4218
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Computer 18
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Ubiquitous Mitochondrial Creatine Kinase (CKMT1) Drives Malignant Creatine Metabolite Profiles in Human Breast Cancer Cell Lines |
1Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States |
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Ubiquitous Mitochondrial Creatine Kinase (CKMT1) is a mitochondrial membrane protein that catalyzes the reversible conversion of creatine (Cr) to phosphocreatine (PCr). This study shows that in two triple-negative breast cancer cell lines, CKMT1-overexpression resulted in significant increases in intracellular Cr and PCr and conferred increases in cell viability while decreasing migration, invasion and adhesion. Since CKMT1 has been identified as a prognostic indicator in several cancers, it may play a role in oncogenesis and/or cancer progression. Thus, CKMT1 holds promise as a potential diagnostic marker and/or treatment target whose expression can be monitored using magnetic resonance spectroscopy-detected Cr and PCr levels. |
| 4219 | Computer 19
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Development of a human heart sized perfusion system for metabolic imaging studies using hyperpolarized [1-13C]pyruvate MRI |
1Department of Clinical Medicine, the MR Research Centre, Aarhus University, Aarhus N, Denmark, 2Department of Anesthesia and Intensive Care, Aarhus University Hospital, Aarhus N, Denmark, 3Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus N, Denmark |
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In order to combat the increasing worldwide organ shortage, increased understanding of the role of deranged metabolism in the donor organ is vital. This is especially true in the case of the heart, where the ability to assess cardiac metabolism during storage pending transplantation, has the potential to utilize marginal organs and elevate the graft viability. Here we present the development of a MR compatible perfusion system used in combination with hyperpolarized [1-13C]pyruvate and conventional MRI. This enables detailed investigations into ex-vivo cardiac metabolism and function in a large animal model, resembling the case in humans. |
| 4220 | Computer 20
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Separation of Intracellular and Extracellular Metabolites during Glucose Fermentation using Diffusion-Weighted Deuterium (2H) Spectroscopy |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada |
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In cancer, high extracellular lactate concentrations are associated with tumour aggressiveness, immune evasion and metastatic potential. We show that diffusion-weighted STEAM 2H-MRS of deuterium-enriched substrates can differentiate between intracellular and extracellular metabolites. Experiments in a model yeast system show the feasibility of detection of intracellular ethanol accumulation, produced via anaerobic fermentation of deuterium enriched glucose. These studies show potential to improve the capability of 2H-MRS for assessment of tumour aggressiveness. |
| 4221 | Computer 21
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Non-invasive intracranial detection of the small molecule inhibitor BAY 1436032 in an orthotopic glioma model using 19F MR spectroscopy |
1Neuroradiology, University Hospital Frankfurt, Frankfurt, Germany, 2Neurooncology, University Hospital Frankfurt, Frankfurt, Germany, 3Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Frankfurt, Germany, 4Research&Development Pharmaceuticals, Bayer AG Berlin, Berlin, Germany |
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BAY 1436032 is a small-molecule inhibitor of the R132X-mutant form of IDH1 with a trifluoromethoxy-group that is currently clinically investigated in IDH1-mutant solid tumors. Non-invasive monitoring of intracranial drug delivery of BAY 1436032 in an animal model using 19F MRS is technically challenging but feasible. |
| 4222 | Computer 22
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Limitation of glucose consumption in rat head detected by labeled glucose-17O |
1Florida State University/NHMFL, Tallahassee, FL, United States, 2MSR, Florida State University/NHMFL, Tallahassee, FL, United States |
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In animal experiments using 17O labeled glucose, questions arose regarding the relatively stable rate of glucose metabolism, compared with a simultaneous variation in glucose concentration after bolus injection. Bolus Glucose-6-17O administration with doses 3-15 μmol/g for normal rats revealed the same glucose consumption with CMRglc = 0.43 ± 0.06 μmol/g tissue/min. After bolus injection, the rate of glucose metabolism was consistent in each dose regardless of the large variation in glucose concentration. The results correlate with the observations of others, indicating that glucose-6-phosphate (G-6-P) does not accumulate in hyperglycemia and can limit glucose consumption. |
| 4223 | Computer 23
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Protocol Optimization for Functional 17O-MRI of Donor Kidneys at 3T |
1Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2German Cancer Consortium Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3NUKEM Isotopes GmbH, Alzenau, Germany, 4Department of Surgery – Organ Donation and Transplantation, University Medical Center Groningen, Groningen, Netherlands, 5Medical Imaging Center, University Medical Center Groningen, Groningen, Netherlands |
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Direct 17O-MRI is able to measure the dynamics of renal metabolism in a porcine kidney in an organ transplantation setup at 3T. To obtain stable SNRs above 20 over time while maintaining a spatial resolution below 8 mm, we investigated the influence of nominal spatial resolution, bandwidth and acquisition time window of a UTE-sequence with a golden-angle acquisition pattern on SNR. Signal increase of up to 25% per liter of 17O-gas was observed in a pilot experiment. |
| 4224 | Computer 24
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Fluorine Nanoparticle Quantification in a Mouse Model of Neuroinflammation: Reference-Based Bias Correction for Conventional and Compressed Sensing Reconstructions |
1Berlin Ultrahigh Field Facility, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany, 2MRI.TOOLS GmbH, Berlin, Germany, 3Experimental and Clinical Research Center (ECRC), Charité Berlin, Berlin, Germany |
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Fluorine-19 MRI has emerged as a promising tool for in vivo cell tracking, yet low achievable signal-to-noise ratios remain a major challenge. Compressed sensing offers increased sensitivity at the cost of introducing signal intensity bias. We show that at low signal levels the quantification performance of compressed sensing is similar to conventional methods due to signal intensity distribution induced bias effects, which also affect the Fourier reconstruction. To improve quantification results, we propose an intensity correction scheme based on ex vivo reference data. |
| 4225 | Computer 25
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Glucose metabolism in the brain of an Alzheimer mouse model by deuterium MRS |
1Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, Netherlands, 2Department of Anatomy, Radboud university medical center, Nijmegen, Netherlands, 3Department of Pediatrics of Radboud Center for Mitochondrial Medicine, Radboud university medical center, Nijmegen, Netherlands |
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In this study we show that Deuterium Magnetic Resonance Spectroscopy (DMRS) of the mouse brain after a bolus application of [6,6’-2H2]glucose is feasible at a high SNR and time resolution. We demonstrate that this can be applied to a transgenic mouse model of Alzheimer disease showing clear differences in the glucose uptake and metabolism with a WT mouse. In Deuterium Metabolic Imaging (DMI) mode this could be an alternative approach for FDG PET in Alzheimer disease. |
| 4226 | Computer 26
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The Effect of B0 Inhomogeneities on Shim Coil Mapping: A Problem and its Solution |
1Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel |
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B0 field inhomogeneities lead to distortions in gradient echo acquired field maps. In particular, these distortions are present when mapping the spatial distribution of a system's shim coils. Here, we assess the effect of these distortions using in-vivo data and computer simulations, and suggest an iterative algorithm which completely removes them without the need of any additional acquisitions. |
| 4227 | Computer 27
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Retrospective Phase-Based Gating for Cardiac Proton Spectroscopy with Fixed Scan Time |
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland, 3Department of Cardiology, Pneumology and Angiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany, 4Department for Cardiology, Pneumology and Angiology, Heinriche Heine University Düsseldorf, Düsseldorf, Germany, 5Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland |
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Respiratory motion is a major limiting factor for the application of cardiac proton MR spectroscopy (MRS) in clinical settings. Prospective navigator gating is frequently applied to minimize respiratory motion effects. However, scan durations are subject-dependent and hence difficult to predict. The present work describes cardiac proton MRS with fixed scan time employing retrospective phase-based gating. It is demonstrated that, relative to prospective navigator gating, the phase-based gating approach provides comparable triglyceride-to-water ratios with predictable scan time. |
| 4228 | Computer 28
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Navigator-free Metabolite-Cycled Cardiac Proton Spectroscopy |
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland |
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Respiratory gating is a burden of conventional cardiac water-suppressed proton spectroscopy and averages are typically phase corrected based on the low-SNR triglyceride signal. Metabolite cycling allows to perform frequency and phase correction on the high-SNR water signal, which might alleviate the necessity for respiratory gating. In this work navigator-free metabolite-cycled cardiac proton spectroscopy was compared with navigator-free water-suppressed and navigator-gated water-suppressed measurements. Analyses based on relative Cramér-Rao lower bounds, creatine-to-water and triglyceride-to-water ratios were performed. Navigator-free metabolite-cycled scans were 3-4 times faster compared to conventional navigator-gated water-suppressed scans while improving signal quality. |
| 4229 | Computer 29
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Characterization of downfield spectra using iRE-MRS |
1Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon PT, Lisbon, Portugal |
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About half of the proton spectrum (downfield of water) has been nearly ignored over the decades of MRS application due to water suppression. We show that ISIS-based Relaxation Enhanced MRS (iRE-MRS) which uses frequency selective excitation and ISIS localization offers short echo times and enhances exchange-broadened resonances. We take advantage of this to characterize the relaxation properties of downfield spectral peaks. |
| 4230 | Computer 30
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Single-voxel short-TR multi-TI multi-TE (SHORTIE) STEAM for water–fat magnetic resonance spectroscopy |
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany, 2Health Systems Philips Schweiz, Zurich, Switzerland |
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Single-voxel MR spectroscopy (MRS) serves as a reference method in fat containing tissues to probe T1, T2 and proton density fat fraction (PDFF). Currently, employed techniques usually rely on long TRs to minimize T1 bias albeit the prolonged scan time and the reduced SNR efficiency. The purpose of this study is to propose the usage of a short-TR multi-inversion time (TI) multi-TE (SHORTIE) STEAM for the simultaneous assessment of T1, T2 and PDFF at reduced scan times when compared to long-TR multi-TI STEAM and long-TR multi-TE STEAM. The agreement between the aforementioned methods was tested in the exemplary application of adipose tissue characterization in the human supraclavicular fossa. |
| 4231 | Computer 31
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Towards probing diffusion barriers for water and metabolites in skeletal muscle by MR spectroscopy using oscillating and pulsed diffusion gradients with a large range of diffusion times |
1Departments of Radiology and Biomedical Research, University Bern, Bern, Switzerland |
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Diffusion-weighted MR spectroscopy has recently been shown to help elucidate the microstructure of brain tissue and the use of oscillating gradients in MRI has provided the option to study local features on a smaller scale. Here, we aim at combining both techniques to investigate human skeletal muscle in vivo on a clinical scanner. Oscillating and pulsed gradient schemes with a large range of diffusion times were applied with otherwise identical acquisition settings. Initial results are shown, but also the challenges faced for muscle where physiologic pulsation and gradient-related artifacts may be prominent. |
| 4232 | Computer 32
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Implementation of metabolite cycled liver 1H MRS on a 7T parallel transmit system |
1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany, 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 3Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile |
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Single-voxel 1H MRS in body applications often suffers from respiratory and other motion induced phase and frequency shifts, which lead to incoherent averaging and hence to suboptimal results. Here we show the application of metabolite cycling (MC) for liver 1H MRS on a 7T parallel transmit system, using 8 transmit-receive fractionated dipole antennas with 16 additional, integrated receive loops. The preserved water signal in MC-MRS allowed for robust phase and frequency correction of individual acquisitions before coil combination and averaging, which resulted in in-vivo liver spectra with an improved spectral resolution as compared with MRS with VAPOR water suppression. |
| 4233 | Computer 33
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Functional Magnetic Resonance Spectroscopy of the Sensory and Attentional Auditory Processing at 7T |
1Radiology, Brigham and Women's Hospital, Boston, MA, United States, 2Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, United States, 3Psychiatry, Veterans Affairs Boston Healthcare System, Brockton, MA, United States |
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This work describes a methodology to perform functional MR spectroscopy ( |
| 4234 | Computer 34
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An in vivo proton magnetic resonance spectroscopy study with multi-echo-time technique for concurrent quantification and T2 measurement of glutamate |
1The Catholic University of Korea, Seoul, Korea, Republic of, 2Gachon University, Incheon, Korea, Republic of, 3Asan Medical Center, Seoul, Korea, Republic of |
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The purpose of the study was to propose a multiple-echo-time (TE) in vivo proton magnetic resonance spectroscopy (MRS) for a concurrent quantification and T2 measurement of glutamate. Point-resolved spectroscopy with eight TE values was used. The validity of selected TEs for T2 estimation of glutamate was verified by the spectral analysis. Comparison results showed that the reliability of the proposed method was comparable to that of typically used MRS techniques for quantification and T2 estimation, respectively. The proposed method can concurrently measure concentration and T2 of glutamate and effectively investigate brain metabolism and microenvironment in an acceptable scan time. |
| 4235 | Computer 35
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T2 Measurement and quantification of cerebral white and gray matter aspartate concentrations in vivo |
1Semenov Institute of Chemical Physics of RAS, Moscow, Russian Federation, 2Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russian Federation, 3Emanuele Institute of Biochemical Physics of RAS, Moscow, Russian Federation |
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In this study for the first time in vivo transverse relaxation rate (T2) of aspartate (Asp) from Asp edited MEGA-PRESS spectra using phanton data were quantified as 161±33 ms. Asp concentrations in gray matter (GM)- and white matter (WM)-dominant brain regions were measured as 2.78±0.21 mM vs 1.04±0.16 mM, respectively. Estimation of the absolute Asp concentrations with Asp editing MEGA-PRESS has potential in many research applications, such as studying the processes underlying the reduction of N‐acetyl aspartate. The T2 measurement method which has been successfully applied for edited Asp signals can also be used for other strongly J-coupled signals. |
| 4236 | Computer 36
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Personalised Water Scaling: Quantifying absolute metabolite concentrations using measured tissue water content and attenuation maps |
1Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada, 3Business Unit MR, Philips, Mississauga, ON, Canada, 4UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, 5ImageTech Lab, Simon Fraser University, Surrey, BC, Canada, 6Radiology, University of British Columbia, Vancouver, BC, Canada, 7Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada |
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A quantitative total water content and relaxation method (TWC) was compared to the commonly used segmentation based approach (SEG) to calculate absolute metabolite concentrations in magnetic resonance spectroscopy. Significantly different water concentrations and attenuation factors were found between TWC and SEG in both grey and white matter from scans of 6 healthy controls at 3T. These differences led to significantly different concentrations of total creatine and myo-inositol in white matter, and N-acetyl-aspartate, total creatine, and glutamate in grey matter. The TWC approach is a promising alternative to improve MRS concentration estimates across healthy and diseased cohorts, and different MRI scanners. |
| 4237 | Computer 37
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Spectral quality differentially affects apparent concentrations of individual metabolites as estimated by linear combination modeling of in vivo MR spectroscopy data at 7 Tesla |
1Biomedical Engineering, Columbia University School of Engineering and Applied Science, New York, NY, United States, 2Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States, 3Radiology, Columbia University Medical Center, New York, NY, United States, 4Neurology, Yale School of Medicine, New Haven, CT, United States |
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In vivo magnetic resonance spectroscopy currently lacks data-driven quality control standards, the development of which can be informed by characterizing the effects of spectral quality on metabolite quantification. We assess the influences of spectral line width and signal-to-noise ratio on both simulated and experimentally derived in vivo resonances from twenty-one metabolites measured by short-echo-time STEAM and J-difference editing for glutathione and GABA at 7 Tesla. We show that spectral quality exerts distinct effects on apparent concentrations of different metabolites, underlining the importance of explicit quality analysis in studies employing in vivo magnetic resonance spectroscopy, especially cross-sectional investigations of physiologically distinct groups. |
| 4238 | Computer 38
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Detection of metabolite concentration changes in young adult volunteer brains after oral glucose administration using short-TE STEAM 1H MRS sequence at 7T |
1Siemens Healthineers, Tokyo, Japan, 2Siemens Healthineers, Malvern, PA, United States, 3Siemens Healthineers, Boston, MA, United States, 4Siemens Healthineers, San Francisco, CA, United States, 5Human Brain Research Center, Kyoto Univeristy, Kyoto, Japan |
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Glucose detection was examined in young adult volunteer brains (the posterior cingulate cortex) with 1H downfield MRS at 7T, and metabolite concentration changes before and c.a. 55 minutes after oral 50-g glucose administration were measured with the downfield and a conventional upfield MRS. The downfield MRS detected H1-α-glucose peak at 5.3 ppm and quantified glucose concentration as a wider range compared to that with the upfield MRS using LCModel. Detection of the H1-α-glucose peak showed a potential to quantify net glucose concentration without underestimation. |
| 4239
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Computer 39
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Recommendations for Accurate Basis Set Generation for Magnetic Resonance Spectroscopy Quantification |
1Biomedical Engineering, Columbia University, New York, NY, United States, 2Radiology, Columbia University, New York, NY, United States |
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Data from magnetic resonance spectroscopy (MRS) experiments require quantification, which consists of fitting the measured data to a series of scaled, shifted and broadened spectral lines, referred to as a basis set. The numerical generation of basis sets necessitates certain assumptions and approximations to ensure practicality given the available computational power and memory size. However, these assumptions can substantially impact the derived spectral lineshapes. Common assumptions found throughout the literature were systematically investigated with our newly developed MAgnetic Resonance Spectrum Simulator (MARSS) software and recommendations are given to generate realistic basis sets for accurate quantification of MRS studies. |
| 4240 | Computer 40
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Quantification issues of in vivo brain 1H NMR spectroscopy revisited |
1Functional Imaging Laboratory, German Primate Center, Göttingen, Germany, 2Department of Cognitive Neurology, University Medicine Göttingen, Göttingen, Germany, 3Georg-August University of Göttingen, Göttingen, Germany |
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Localized proton NMR spectroscopy is capable to measure in vivo brain metabolites in different diseases. Accuracy and precision of the quantification of metabolite concentrations is key, especially when comparing results from different patients, diseases, groups, sites or even species. Here we demonstrate that deterioration in SNR of the spectra does not only degrade the precision of obtained values but also could cause severe alterations of estimated absolute concentrations. E.g. aberrations of up to 100% or 8 mMol/L were found in Glx (Glutamate+Glutamine) concentrations. |
| 4241 | Computer 41
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No-Cost, Vendor-Agnostic MR Spectroscopy Fitting Software Can Predict Diagnostic Quality and Utility of Clinical Brain Studies |
1Department of Imaging Physics, The UT MD Anderson Cancer Center, Houston, TX, United States, 2Department of Diagnostic Radiology, The UT MD Anderson Cancer Center, Houston, TX, United States |
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MR spectroscopy (MRS) allows for non-invasive assessment of tissue metabolites and is rapidly expanding in clinical use. Current MRS QC recommendations, however, are phantom-based and infrequent. This study investigated the feasibility of using no-cost, vendor-agnostic fitting software to provide quantitative quality assessment of patient brain MRS. We demonstrated that freely-available MRS fitting software can stratify spectral diagnostic quality and utility. This technique can be used to provide the clinician with an estimate of quality for each patient spectrum. Additionally, this approach is amenable to real-time patient MRS quality verification and longitudinal monitoring of protocol performance. |
| 4242 | Computer 42
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A Time Series Analysis Method to Achieve Improved Water Suppression in 1H MRS |
1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States |
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Adequate suppression of water signal is vital in detecting low concentration metabolites in in-vivo proton spectroscopy acquisitions. This problem, which is exacerbated in the presence of multiplicative noise induced by physiological motion, is not addressed by current water and lipid saturation-based approaches. Here we use a time series modeling approach and show that signal estimation techniques are extremely effective in suppressing the highly correlated physiological noise component to achieve over three orders of magnitude in-vivo water suppression. |
| 4243 | Computer 43
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Impact of wavelets and apodisation in magnetic resonance spectroscopy quality for paediatric brain tumours |
1Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom, 2Birmingham Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom |
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Ependymomas, medulloblastomas and pilocytic astrocytomas are common paediatric central nervous system tumours. In vivo 1H magnetic resonance spectroscopy is a non-invasive technique to determine tumour metabolic characteristics, however suffers from limited signal-to-noise ratios. Our previous studies demonstrated that metabolite concentration estimation may be improved through wavelet de-noising on both simulated and in vivo MRS data, as reflected by improved tumour classification. In this study we compared improvements in fit quality using both wavelets and apodisation on simulated and in vivo MRS data of the three tumours by measuring overall and regional SNR. |
| 4244 | Computer 44
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Effects of outer volume saturation RF pulses and chemical shift displacement on MRS data |
1Neuroimaging, King's College London, London, United Kingdom, 2Department of Medical Physics, University of Thessaly, Larissa, Greece |
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We investigated the effect of outer volume saturation (OVS) using very selective saturation pulses (VSS) on metabolite concentrations in PRESS MRS. Our results show that if the PRESS excitation voxel isn’t increased in size, metabolite concentrations are overestimated compared with not using VSS-OVS. These results will be of interest to other researchers planning or conducting multi-centre MRS studies. |
| 4245
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Computer 45
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The use of multi-vendor, multi-site 1H-MRS data acquired at 26 sites as a benchmark for MRS standardization: Comparison of quantification software |
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Imaging Institute, Cleveland Clinic Foundation, Cleveland, OH, United States, 4Radiology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States, 5Department of Radiology, Haukeland University Hospital, Bergen, Norway, 6Spinoza Centre for Neuroimaging, Amsterdam, Netherlands, 7Department of Radiology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, United States, 8Department of Radiology, Taipei Medical University Shuang Ho Hospital, New Taipei City, Taiwan, 9Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway, 10NORMENT – Norwegian Center for Mental Disorders Research, University of Bergen, Bergen, Norway, 11Department of Kinesiology, KU Leuven, Leuven, Belgium, 12REVAL Rehabilitation Research Center, Hasselt University, Leuven, Belgium, 13Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany, 14Brain and Consciousness Research Centre, Taipei Medical University, Taipei, Taiwan, 15School of Health Sciences, Purdue University, West Lafayette, IN, United States, 16Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States, 17Department of Neuroimaging, Central Institute of Mental Health, Mannheim, Germany, 18Shandong Medical Imaging Research Institute, Shandong University, Jinan, China, 19Helen Wills Neuroscience Institute, University of California, Berkeley, berkeley, CA, United States, 20Department of Radiology, University of Calgary, Calgary, AB, Canada, 21Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China, 22Department of Neurology, BG University Hospital Bergmannsheil, Bochum, Germany, 23Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom, 24Department of Radiology, Taipei Veterans General Hospital, National Yang-Ming University, School of Medicine, Taipei, Taiwan, 25Department of Radiology, Maastricht University Medical Center, Maastricht, Netherlands, 26Department of Psychiatry, Columbia University, New York, NY, United States, 27New York State Psychiatric Institute, New York, NY, United States, 28GE Healthcare, Calgary, AB, Canada, 29GE Healthcare, Taipei, Taiwan, 30Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States, 31National High Magnetic Field Laboratory, Gainesville, FL, United States, 32Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 33Department of Psychiatry, Columbia University, new york, NY, United States, 34Department of Psychology, University of Washington, Seattle, WA, United States, 35Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States, 36GE Healthcare, Berlin, Germany, 37Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada, 38Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States, 39Center For Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, United States, 40Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States, 41Department of Radiology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States, 42Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, 43Department of Psychiatry, University of Toronto, Toronto, ON, Canada, 44Department of Psychiatry and Behavioral Sciences, University of Minnesota, Minneapolis, MN, United States, 45School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada, 46Leuven Research Institute for Neuroscience & Disease (LIND), KU Leuven, Leuven, Belgium, 47Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University, Duesseldorf, Germany, 48Department of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 49Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States, 50Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University, Duesseldorf, Germany |
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In vivo 1H-MRS is useful for studying neurological pathology, however its integration into clinical routine remains incomplete. Quantification of 1H-MRS data is affected by the analysis pipeline, but the source and extent of this bias is often unknown. Therefore, a large multi-vendor, multi-site dataset (n=296) was processed with an automated pipeline and three quantification software packages: LCModel, TARQUIN, and QUEST. Pearson’s correlation coefficient ranged from 0.66-0.88 for LCModel vs. TARQUIN and from 0.02-0.47 for QUEST vs. LCModel and QUEST vs. TARQUIN. A different baseline handling was the major potential source of variation between quantification software. |
| 4246 | Computer 46
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Windowed whitened singular value decomposition (wWSVD): An improved data-driven strategy for combining MR spectra from multi-channel phased array coils |
1Department of Radiology & Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 2Department of Biomedical Engineering, Duke University, Durham, NC, United States, 3MR R&D Collaborations, Siemens Healthineers, Los Angeles, CA, United States |
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Data driven methods to combine multi-channel phased array data such as singular value decomposition (SVD) can greatly improve SNR in MR spectra. Current SVD implementation has two primary limitations: 1) the assumption that noise is independent between coil channels; and 2) utilization of the entire spectrum to calculate the optimized coil combination. Here, we present a method using a whitened SVD (WSVD) matrix to decorrelate noise from individual coil elements, followed by an optimized and iterative windowing approach termed windowed whitened SVD (wWSVD) to determine the optimal subset of the spectrum for SVD analysis that is then used to combine multi-channel spectral data. We report a significant in vivo improvement in spectral SNR using wWSVD over WSVD. |
| 4247 | Computer 47
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Pointwise T2 fitting for spectral relaxography: examples in dystrophic and healthy muscle |
1Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, United States, 2University of Florida, Gainesville, FL, United States |
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We present a model-free approach for frequency domain transverse relaxation time (T2) analysis and post-processing. Multiple echo-time (TE) magnetic resonance spectroscopy (MRS) data is fit for M0 and T2 at each point in the frequency spectrum to produce derived plots of T2 as a function of chemical shift. T2 values of certain in-vivo resonances are in good agreement with prior literature. The spectral T2 (sT2) obtained by pointwise fitting and plotting shows remarkably defined features. Results are shown for spectra obtained from normal leg muscle and muscle in subjects with Duchenne Muscular Dystrophy (DMD). |
| 4248 | Computer 48
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Characterization of Downfield Resonances and their T2 Relaxation times in Human Brain at 9.4 T |
1MRZ, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tübingen, Tuebingen, Germany |
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In this abstract, we report the apparent T2 relaxation times of the downfield peaks in the human brain at 9.4 T. In addition, we look for correlations between different downfield peaks and between downfield and upfield metabolites. Further, concentrations of all downfield resonances after correcting for both water and peak relaxation times are reported for the first time. |
| 4249 | Computer 49
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Comparison of 7T MRS Reproducibility Using either Creatine or Water Referencing in Patients with Schizophrenia |
1Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, United States |
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This study investigated the reproducibility of 7T MRS of gray and white matter in ten patients with schizophrenia (SZ), using either water or total creatine (tCr) as internal references. All ‘high concentration’ metabolites such as NAA, glutamate, choline and others, and some low concentration metabolites, such as glutamine and NAAG were reliably determined. Referencing to either water or tCr gave similar reproducibility. |
| 4250 | Computer 50
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Ultra-high field MRS and high spatiotemporal resting fMRI of the default mode network: A reproducibility study |
1Medicine and Radiology, University of Melbourne, Parkville, Australia, 2Monash University, Monash, Australia, 3Alfred Hospital, Richmond, Australia |
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This study investigated the reproducibility of measuring brain glutamatergic nuerotransmitters and glutathione using MRS, and their correlation with high spatiotemporal resolution resting state fMRI and subject age at 7T. Repeat MRS measurements across two time points showed excellent reproducibility (ICC > 0.75) for all metabolites. Both the ratio of Glutamate/Gaba and functional connectivity correlated independently with subject age. Ultra-high field MR is ideal for studying the association between brain biochemistry and function in neurological diseases. |
| 4251 | Computer 72
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Proton MRS and resting state fMRI study of hyperbaric oxygenation effects at 3 Tesla |
1Emanuel Institute of Biochemical Physics of RAS, Moscow, Russian Federation, 2Radiology, Clinical and Research Institute of Emergency Pediatric Surgery and Traumatology, Moscow, Russian Federation, 3Semenov Institute of Chemical Physics of the Russian Acedemy of Sciences, Moscow, Russian Federation, 4Clinical and Research Institute of Emergency Pediatric Surgery and Traumatology, Moscow, Russian Federation |
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Previously we demonstrated that one hyperbaric oxygenation (HBO) session causes the energy metabolism activation in order to compensate the expenses on NAD(H) synthesis. This study is aimed to reveal the effects of HBO on the 1H MRS brain metabolites and the correlated activity in DMN at 3 Tesla. The results demonstrate that even one low-pressure HBO session in healthy subjects stimulates NAA brain metabolism and increases the MPFC-PCC functional connectivity. Further research of HBO effects on neuronal pathology subjects is of interest. |
| 4252 | Computer 73
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Error estimate in temperature measurement using 1H MRS with water suppression |
1Department of Pshchiatry, Columbia University, New York, NY, United States, 2Division of Molecular Imaging, New York State Psychiatric Institute, New York, NY, United States |
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Proton MRS thermometry exploits the property of temperature dependence of water signal. Most of MRS thermometry utilizes partially suppressed water signal or separately measured water signal without water suppression, in addition to the water suppressed signal for metabolites. This work shows that these approaches are either inaccurate or imprecise. The resultant errors may undermine clinically significant temperature changes. Simultaneous or interleaved measurement of unsuppressed water signal and metabolite/lipid signal is desirable. |
| 4253 | Computer 74
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Regional Differences in Cerebral Phenylalanine Measured with Single Voxel Spectroscopy using PRESS localization and LCModel Quantification |
1Radiology, Brigham and Women's Hospital, Boston, MA, United States, 2Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, United States |
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This work describes a methodology for the quantification of phenylalanine in the brain, using standard single voxel spectroscopy with PRESS localization and LCModel quantification. The signals downfield from the water peak were modeled incorporating metabolite basis functions to the standard LCModel basis set. Phantom calibrations tailored for the acquisition protocol were performed to obtain corrected concentration ratios that showed significant regional differences (p<0.001) and high intrasubject correlation (R=0.73). |
| 4254 | Computer 75
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Distribution of Major Brain Metabolite Ratios in Adults: The Observations of Whole Brain Magnetic Resonance Spectroscopic Imaging Study |
1Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan, 2Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan, 3Global Station for Quantum Medical Science and Engineering, Hokkaido University, Sapporo, Japan, 4Hokkaido University Hospital, Sapporo, Japan, 5Siemens Healthineers, San Francisco, CA, United States, 6Siemens Healthcare K.K., Tokyo, Japan |
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We evaluated the normative major metabolite ratios of adults by using whole-brain magnetic resonance spectroscopic imaging (MRSI). The major metabolite ratios of the brain vary with region, age |
| 4255 | Computer 51
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Allysine-targeting gadolinium-based MRI probes for imaging lung fibrogenesis |
1Radiology, A. A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, 2Department of Medicine: Pulmonary, Allergy, Sleep and Critical Care Medicine, Boston University School of Medicine, Boston, MA, United States |
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There is an enormous unmet medical need for non-invasive methods to assess lung fibrosis that can distinguish between active disease and stable scar. Here, we report on a gadolinium-containing contrast agent Gd-CHyd that targets fibrogenesis (active fibrosis) by undergoing a condensation reaction with allysine, an abundant aldehyde motif on fibrosing tissue. This probe reacts with aldehydes at a rate that is an order of magnitude faster than the parent probe Gd-Hyd. This faster reactivity leads to higher accumulation of the probe in the lungs of bleomycin treated mice (mouse model of lung fibrosis) and two-fold contrast enhancement relative to Gd-Hyd. |
| 4256 | Computer 52
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Toward in vivo quantification of microparticles of iron oxide targeting cerebrovascular inflammation |
1Sherbrooke Molecular Imaging Center (CIMS), Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany |
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Microparticles of iron oxide (MPIOs) can be detected by MRI with high sensitivity. This has recently led to their utilization as efficient contrast agents for molecular imaging or cell tracking. We present first steps toward in vivo quantification of a targeted MPIO that is widely used for inflammation imaging. These steps include 1) relaxivities and molar susceptibility measurements on a phantom, 2) in vivo estimation of the concentration of inflammation-specific MPIOs in a mouse model of cerebrovascular inflammation and 3) acquisition of ex vivo images that validate the results obtained in vivo. |
| 4257 | Computer 53
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Molecular MR imaging of Acute Inflammation using a Biochemically Responsive Iron-Based Contrast Agent |
1Radiology/ Martinos Center, Massachusetts General Hospital, Charlestown, MA, United States |
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The redox active MRI contrast agent Fe-PyC3A is shown to provide strong, selective contrast enhancement of acutely inflamed pancreatic tissue in a murine model. Fe-PyC3A is administered in the weakly contrasting Fe(2+) oxidation state but is converted to the 15-fold more strongly contrasting Fe(3+) state in the presence of reactive oxygen species (ROS). Fe-PyC3A does not provide contrast enhancement of normal pancreas, but provides significant contrast enhancement of inflamed pancreas. Pancreatic enhancement correlates tightly with activity levels of the pro-inflammatory biomarker myeloperoxidase. This is the first example of using metal ion redox for MR imaging of pathologic change in vivo. |
| 4258 | Computer 54
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TAT-functionalized perfluorocarbon nanoemulsion for 19F imaging of CAR T cells in vivo. |
1Radiology, University of California San Diego, La Jolla, CA, United States, 2Bioengineering, University of California San Diego, La Jolla, CA, United States, 3Pharmacology, University of California San Diego, La Jolla, CA, United States, 4Neurological Surgery, University of California San Francisco, San Francisco, CA, United States |
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To improve the utility of 19F MRI to detect lymphocytes in vivo, we looked into strategies to increase cell loading via the use of |
| 4259 | Computer 55
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Beta-amyloid specific in vivo MR imaging with chalcone conjugated gadolinium complex. |
1Medical and bioengineering, Kyungpook national university, Daegu, Korea, Republic of, 2Molecular Medicine & BK21 Plus KNU Biomedical Convergence Program, Kyungpook national university, Daegu, Korea, Republic of, 3Institute of Biomedical Engineering Research, Kyungpook national university, Daegu, Korea, Republic of, 4Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea, Republic of, 5Radiology, Kyungpook national university, Daegu, Korea, Republic of |
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A new gadolinium complex conjugated with chalcone derivative (GdL) shows beta-amyloid specific enhancement in vivo MR imaging. The enhanced region in MR image matched well with fluorescence imaging of beta-amyloid plaque, which was stained by thioflavin S. The difference of signal enhancement between GdL and Gadovist in beta-amyloid oligomer supported that GdL has specificity on beta-amyloid. In addition, GdL shows considerable relaxivities even at high field 9.4 T (r1 = 4.60, r2 = 5.71 mM-1s-1) and comparable kinetic stability compared with commercial MRI agents. |
| 4260 | Computer 56
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Development of a novel theranostic NPs composed of Fe3O4, Trastuzumab and indocyanine green for diagnosis and treatment of HER-2 positive breast cancer |
1Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 2GE Healthcare, Beijing, China |
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Superparamagnetic iron oxides can be used as contrast agents for MR T2-weighted imaging. We created multifunctional nanoparticles based on Fe3O4, Trastuzumab and indocyanine green (ICG) to target HER2 positive breast cancer cells in vitro and vivo. Firstly, internalization was assessed on HER-2 positive breast cancer SK-BR-3 cells by transmission electron microscopy (TEM). Furthermore magnetic resonance imaging (MRI) and fluorescence imaging were used to examine the biodistribution and its targeting effect in vivo. Additionally, photothermal therapy (PTT) was further evaluated to examine the treatment effect of NPs. As a result, Fe3O4-trastuzumab-ICG have shown great potential to become an effective multifunctional imaging agent and a tool for photothermal therapy for HER-positive breast cancer. |
| 4261 | Computer 57
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A noninvasive T1-weighted MR tool for tracking of vicinal thiols motif of thioredoxin protein in live cells |
1Bio-imaging Research Team, Korea Basic Science Institute, Chungcheongbuk-do, Korea, Republic of, 2Chungnam National University, Daejeon, Korea, Republic of, 3Amrita School of Engineering, Ettimadai, India |
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We have synthesized a couple of new MRI contrast agent for recognition of cellular vicinal thiols motif protein thioredoxin. |
| 4262 | Computer 58
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Quantitative Time-dependent Mapping of Liver Cirrhosis Heterogeneity with A Protein-based MRI Contrast Agent |
1Biomedical Engineering, Georgia Institute of Technology / Emory University, Atlanta, GA, United States, 2Department of Chemistry, Georgia State University, Atlanta, GA, United States |
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This work is focused on quantitative and qualitative analysis of the spatial and time-dependant heterogeneity of liver cirrhosis using a novel protein-based MRI contrast agent which targets collagen type I. |
| 4263 | Computer 59
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Macrocyclic Manganese (II) Complex of Mefenamic acid (MA) Conjugate as an Inflammation Targeting MRI Contrast Agent |
1Medical and Biological Engineering, Kyungpook National University, Daegu, Korea, Republic of, 2Molecular Medicine, Kyungpook National University, Daegu, Korea, Republic of, 33Institute of Biomedical Engineering Research, Kyungpook National University, Daegu, Korea, Republic of, 4Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea, Republic of, 5Radiology, Kyungpook National University, Daegu, Korea, Republic of |
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The purpose of the present study is to design and synthesis of novel macrocyclic Mn2+ complex as an alternative to the well-established Gd3+ based chelates for use as an inflammation targeting MR imaging agent. This new complex exhibits higher r1 relaxivity (2.32 mM−1 s−1) than clinically approved Mn-DPDP® (1.6 mM−1 s−1) at 4.7 T. T1-weighted MR coronal images display strong signal enhancement in liver, heart, gallbladder and kidney. In an inflammatory mouse model, it shows greater inflammatory tissues detection with in a clinical dose. |
| 4264 | Computer 60
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Determination of the fate of intravenously administered Gd(III)DOTA-DSPE-based liposomal contrast agent in a mouse model |
1Pediatric Radiology, Texas Children's Hospital, Houston, TX, United States, 2Radiology, Baylor College of Medicine, Houston, TX, United States, 3Baylor College of Medicine, Houston, TX, United States, 4Texas Children's Hospital, Houston, TX, United States |
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Small molecule conventional gadolinium (Gd) present major safety concerns including nephrogenic systemic fibrosis (NSF) and brain accumulation. Liposomal Gd(III)DOTA-DSPE conjugate exhibit high relaxivity at clinically-relevant MR field strength, and enables molecular MR imaging mice. We report herein an investigation on the pharmacokinetics, bio-distribution and clearance of a liposomal-Gd agent in mice over a period of 28 days by T1-weighted MR imaging and ICP-MS analyses. Results show no significant skin or brain accumulation, suggesting NSF and brain accumulation concerns may be unlikely with such agent. |
| 4265 | Computer 61
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A Predictive Model for Chronic Low Back Pain Objective Diagnosis Exploiting Multi-Modal Brain [11C]-PBR28 PET/MR Radiomic Features |
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States, 3Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, MA, United States, 4Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States |
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Chronic pain affects more than 100 million individuals in the United States alone. However, our ability to diagnose and properly treat pain disorders is currently limited, including due to the lack of reliable biomarkers. In this work, we present a predictive model for the classification of chronic low back pain (cLBP) patients using multi-modal brain [11C]-PBR28 PET/MR radiomic features extracted from structural, functional, and molecular imaging. Our results suggest that a PET/MR classifier (RFPET/MR) performs better than single-modality classifiers (RFPET and RFMR) for AUC (p’s<0.01), accuracy (p’s<0.01), sensitivity (p’s<0.05), and specificity (p’s<0.01), highlighting the power of multi-modal over single-modality imaging. |
| 4266 | Computer 62
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18F-Fluoroethyltyrosine PET and Multiple Quantum Filtered Sodium MRI in Cerebral Gliomas |
1Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich GmbH, Jülich, Germany, 2Institute of Neuroscience and Medicine - 11, Forschungszentrum Jülich GmbH, Jülich, Germany, 3Department of Nuclear Medicine, RWTH Aachen University, Aachen, Germany, 4Jülich-Aachen Research Alliance (JARA) - Section JARA-Brain, Aachen, Germany, 5Department of Neurology, RWTH Aachen University, Aachen, Germany |
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[18F]-FET-PET and sodium MRI were carried out on a cohort of patients with untreated cerebral gliomas. It is shown that the results from multiple quantum filtered sodium MRI using the enhanced SISTINA sequence are related to IDH mutational status in contrast to [18F]-FET-PET, thus providing the diagnostic potential to predict the genetic profile of gliomas. |
| 4267 | Computer 63
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Monitoring the Biodegradation of Implanted Hydrogel Cell Scaffolds using CEST MRI |
1Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 2Department of Urology, Johns Hopkins University, Baltimore, MD, United States |
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Scaffolding cells with hydrogels is a promising strategy to treat many tissue injuries and diseases. Observing hydrogel degradation is essential as it correlates to the cell release from the hydrogel. We monitored implanted hydrogel degradation using CEST MRI, with validation using two-color in vivo near-infrared imaging. An excellent correlation was found between these two methods, with gelation as the major decomposing component. The results demonstrate that CEST MRI can serve as a robust tool for monitoring hydrogel degradation in vivo. |
| 4268 | Computer 64
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An efficient cell-permeable T1 contrast agent for labeling and tracking human embryonic stem cells on MRI |
1Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada, 2Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada, 3The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada |
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Human embryonic stem cells (hESCs) are pluripotent and, thus, have enormous potential as therapeutic cells in regenerative medicine. Non-invasive tracking of transplanted cells is critical for advancing cell-based therapies. MRI has emerged as an important technique for monitoring the fate of transplanted cells. However, conventional cellular MRI uses superparamagnetic iron oxide nanoparticles (SPIOs) that have limited specificity. To improve specificity, we developed a highly efficient, cell-permeable T1 agent for labeling hESCs without affecting cell viability, proliferation, or function. MR imaging of transplanted hESCs demonstrates sensitive detection of labeled cells in vivo. |
| 4269 | Computer 65
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Dysprosium complexes encapsulated apoferritin T2 MRI contrast agent for ultra-high field MRI |
1Department of Molecular Medicine & BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University, Daegu, Korea, Republic of, 2Institute of Biomedical Engineering Research, Daegu, Korea, Republic of, 3Department of Medical &Biological Engineering, Kyungpook National University, Daegu, Korea, Republic of, 4Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea, Republic of, 5Department of Radiology, Kyungpook National University, Daegu, Korea, Republic of |
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Apo[Dy(DO3A-ph-NH2)] is synthesized according to the precede literature. The absorbance is changed at 300-400 nm after encapsulation of Dy(DO3A-ph-NH2), and we confirmed the morphology of Dy(DO3A-ph-NH2) encapsulated protein with TEM image. The final concentration of paramagnetic composition is calculated by ICP. The relaxivities of Dy(DO3A-ph-NH2) encapsulated protein at various external fields (3 - 15.2 T) are considerably increased, and also r2/r1 ratios are increased up to 55 at 15.2 T. |
| 4270 | Computer 66
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Liver Distribution and Delayed Phase Liver Enhancement using Mn-PyC3A |
1Surgical Oncology, Massachusetts General Hospital/ Harvard Medical School, Boston, MA, United States, 2Radiology/ Martinos Center, Massachusetts General Hospital, Charlestown, MA, United States |
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Mn-PyC3A was rationally designed as a Gd-free alternative to commercially available MRI contrast agents. Quantification of Mn excretion using rats shows that the agent is efficiently eliminated with a fractional clearance that is 85% renal and 15% hepatobiliary. Based on the substantial fractional hepatobiliary excretion, we hypothesized that Mn-PyC3A would provide delayed, liver specific contrast enhancement that can be used to identify liver tumors. Mn-PyC3A was demonstrated to provide delayed phase liver enhancement that rendered liver tumors conspicuously hypointense in a murine model of colorectal metastasis. |
| 4271 | Computer 67
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Micelles-like Biodegradable conjugates as Biocompatible MRI Contrast Agents for Advanced Imaging of Tumor and Angiography |
1Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan Unversity, Chengdu, China |
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To improve the contrast enhancement of solid tumor, we prepared enzymes responsive biodegradable micelles-like agents (MpH-DOTA-Gd), and the HMPA based micelle-like polymeric MR contrast agents provided a possibility of selectively great contrast in MR imaging of tumor and angiography. |
| 4272 | Computer 68
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In vivo Fast Field Cycling Relaxometry reports on the extra- and intracellular localization of iron oxide particles in tumour mice models. |
1University of Torino, Torino, Italy |
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A new sensitive, non invasive, imaging methods capable of a quantitative detection of Tumour Associated Macrophages (TAM) is herein proposed. The method is based the use Fast Field Cycling (FFC) relaxometers to assess the localization of ferumoxytol in TAM in melanoma tumours. The observed 1/T1 NMRD profiles appear highly dependent on the intra or extra cellular localization of the NPs thus allowing an unambiguous TAM quantification. |
| 4273 | Computer 69
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Fluorous-metal chelate for sensitive 19F MRI paramagnetic nanoemulsion cell labels |
1Department of Pharmacology, UC San Diego, La Jolla, CA, United States, 2Department of Radiology, UC San Diego, La Jolla, CA, United States |
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Fluorine-19 MRI is a cellular imaging approach enabling quantitative ‘hot-spot’ imaging with no background. The utility of 19F-MRI to detect inflammation and cell therapy in vivo could be expanded by improving the intrinsic sensitivity of the probe by molecular design. We describe a small molecular weight fluorinated metal chelate (SALTAME) based on a salicylidene-tris(aminomethyl)ethane core, with solubility in perfluorocarbon (PFC) oils. SALTAME additive to nanoemulsion is a potent accelerator of 19F T1 and increases the image sensitivity per time with signal averaging. We assessed the biocompatibility, potential 19F signal enhancement and use for detecting inflammation macrophages in mice in vivo. |
| 4274 | Computer 70
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Parahydrogen induced hyperpolarization of [1-13C] pyruvate for metabolic imaging in cancer research |
1Information Science and Technology, Hokkaido University, Sapporo, Japan |
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13C-labeled pyruvate is a clinically available key tracer for hyperpolarized 13C metabolic MRI study. An automated hyperpolarizing system of [1-13C]pyruvate using a low-cost parahydrogen induced polarization (PHIP) with side-arm hydrogenation (SAH), in which hyperpolarization is initially induced to the parahydrogen derived two 1Hs on unsaturated pyruvate precursor followed by the polarization transfer to a 13C of pyruvate, was developed. Magnetic field cycling process for 1H-to-13C polarization transfer process was optimized by the experimentally determined J-coupling network of pyruvate precursor and quantum chemical simulation, and its possible applications for cancer research are investigated in tumor-bearing mouse model. |
| 4275 | Computer 71
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Distinguishing Closely Related Pancreatic Cancer Subtypes by Glucose Metabolic Imaging Using 13C-MRS without Hyperpolarization |
1National Cancer Institute, Bethesda, MD, United States, 2Hokkaido University, Sapporo, Japan, 3Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States, 4GE Healthcare, Dallas, TX, United States, 5GE Healthcare, Toronto, ON, Canada, 6Technical University of Denmark, Lyngby, Denmark |
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Metabolic differences both between patients and within the tumor itself can be an important determinant in cancer treatment outcome; however, methods for determining these differences non-invasively in vivo have been lacking. Using pancreatic ductal adenocarcinoma as a model, we demonstrate that xenografts with a similar genetic background can be distinguished by differing rates of glucose metabolism, which can be imaged by 13C glucose without hyperpolarization using a newly developed technique for noise suppression. Using this method, cancer subtypes that appear similar in mass spectrometry tissue biopsies and hyperpolarized MRI pyruvate metabolism measurements can be easily distinguished. |
| 4276 | Computer 76
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HyperMaple: Maple Syrup as a Glassing Agent for DNP Sample Preparation |
1Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Headington, United Kingdom, 2Department of Physiology Anatomy & Genetics, University of Oxford, Oxford, United Kingdom |
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Certain compounds require a glassing agent to be hyperpolarized for dynamic nuclear polarization experiments. We propose here the novel use of Canadian maple syrup, a delicious, hypoallergenic, and readily available concentrated sugar solution, as an alternative to conventional glassing agents such as dimethyl sulfoxide and glycerol, and have demonstrated its utility in hyperpolarizing [13C]urea. |
| 4277 | Computer 77
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Pyruvate keto-enol tautomerization and its potential impact on apparent pyruvate T1 |
1Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Headington, United Kingdom, 2Department of Physiology Anatomy & Genetics, University of Oxford, Oxford, United Kingdom, 3Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom |
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Pyruvic acid is the most commonly studied metabolic agent for dynamic nuclear polarization. In aqueous solution, pyruvic acid can exist in three forms: hydrate (gem-diol), keto, and enol. The composition depends on pH. This study investigates the differences in longitudinal relaxation properties of the three tautomers with the objective of further understanding the factors contributing to the apparent T1 of pyruvic acid. |
| 4278 | Computer 78
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Investigating Pre-Saturation of Inflowing Lactate for Improving Human Hyperpolarized 13C-Pyruvate Brain Studies |
1UCSF, San Francisco, CA, United States |
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Dissolution dynamic nuclear polarization has enabled real-time metabolic imaging in both pre-clinical and clinical research applications. However, pre-clinical studies have provided evidence that inflowing metabolites can bias measurements in a number of organs. In this work, we explored the impact of inflowing lactate spins on quantitative hyperpolarized pyruvate 13C MRI of the human brain in a healthy volunteer. We provide evidence in a healthy volunteer that by pre-saturating inflowing lactate to address this confounding factor, kPL values in the brain were reduced by ~15%. Further studies will increase the sample size to better characterize this effect. |
| 4279 | Computer 79
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An Optimized GRASE Sequence for Preclinical and Human Hyperpolarized 13C Imaging |
1University of California at San Francisco, San Francisco, CA, United States, 2University of California at Berkeley, Berkeley, CA, United States |
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An optimized GRASE sequence was developed for dynamic hyperpolarized 13C Imaging and demonstrated the feasibility for human brain research. The multi-echo signal can either be used to encode a 3D volume or as a 2D multi-echo approach to increase SNR or estimate T2. Varied crusher gradients were investigated to reduce the loss of longitudinal hyperpolarized 13C magnetization. |
| 4280 | Computer 80
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Partial Fourier Reconstruction of Hyperpolarized 13C EPI in the Human Brain |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada, 4Pharmacy, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 5Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada |
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Asymmetric in-plane k-space sampling of EPI can reduce the minimum achievable TE in hyperpolarized 13C with spectral-spatial radio frequency pulses, thereby reducing T2* weighting and signal-losses. Partial Fourier image reconstruction exploits the approximate Hermitian symmetry of k-space data and can be applied to asymmetric data sets to synthesize unmeasured data. Here we present the results of applying partial Fourier image reconstruction from hyperpolarized [1-13C]pyruvate scans in human brain. A quantitative evaluation of image sharpness using no-reference image quality assessment agreed with a perceived improvement in contrast and resolution. |
| 4281 | Computer 81
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Limits of Kinetic Modeling for Myocardial Infarction and Border Zone Detection Using Hyperpolarized 13C Magnetic Resonance Imaging |
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland |
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Kinetic modeling of hyperpolarized [1-13C]-pyruvate imaging allows quantification of cardiac metabolism. In this work, SNR is identified as a limiting factor for the detection of focal lesions and border zones with hyperpolarized 13C imaging under typical in-vivo conditions. Moreover, limits are determined with respect to SNR and resolution requirements. Based on calculated maps of kinetic conversion rates, infarcted areas with transmuralities ≥ 33% are distinguishable from remote myocardium even at a modest resolution of 10mm, while altered metabolism in the border zone (area-at-risk) is not detectable, even at higher resolutions of 5mm. |
| 4282 | Computer 82
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Hyperpolarized metabolic imaging with high SNR in vivo using low volume photo-induced nonpersistent trimethylpyruvic acid radicals |
1Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland, 2Department of Electrical Engineering Technical University of Denmark, Center for Hyperpolarization in Magnetic Resonance, Kgs Lyngby, Denmark |
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Recently it was demonstrated that UV irradiation of trimethylpyruvic acid (TMP) generates nonpersistent radicals with narrow electron spin resonance linewidth. TMP however has never been used to hyperpolarize 13C substrates to study in vivo metabolic processes, and relatively large volumes of TMP were needed to generate high nonpersistent radical concentrations. The aim of this study was to increase the nonpersistent radical yield in TMP-doped [1-13C]lactic acid, [1-13C]butyric acid and 13C glucose preparations to achieve high polarization levels. In vivo metabolism was measured with signal levels similar to that of persistent radical preparations, demonstrating TMP as a promising nonpersistent radical for dissolution DNP and potential clinical translation. |
| 4283 | Computer 83
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Phenylglyoxylic acid as a generic UV-induced radical precursor to hyperpolarize 13C-labelled substrates for in vivo metabolic studies |
1Institute for Bioengineering of Catalonia, Barcelona, Spain, 2University of Cambridge, Cambridge, United Kingdom, 3Aix-Marseille University, CNRS, ICR, Marseille, France, 4Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Technical University of Denmark, Lyngby, Denmark, 5GE Healthcare, Cambridge, United Kingdom |
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Photo-irradiation of phenylglyoxylic acid (PhGA) using visible light produces a non-persistent radical that, in principle, can be used to hyperpolarize any molecule. We show that PhGA can be used as a radical precursor to polarize photo-sensitive metabolic substrates (such as the gluconeogenic probe 13C-dihydroxyacetone) as well as 13C-glucose. We also present our preliminary DNP data obtained in PhGA-doped samples using a novel custom-built cryogen-free 7T/1.4K polarizer. |
| 4284 | Computer 84
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Over 70% 13C polarization on [U-13C]glucose |
1Electrical Engineering, Danish Technical University, Kongens Lyngby, Denmark |
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The undisputed usefulness in biomedical applications, the high carbon polarization (up to 70%) and the long relaxation time constant have made “neat [1-13C]pyruvic acid plus trityl” the most studied dissolution-DNP sample. Nevertheless, too often results valid for this particular preparation are considered to hold also for other trityl-based samples, limiting the potential of other biologically interesting substrates. In the present study we demonstrate that the sample composition and magnetic field affect the trityl ESR properties. A thorough optimization of the these parameters lead to a dramatic increase of [U-13C]glucose polarization from 37±4% to 69±3%, the highest value reported to date. |
| 4285 | Computer 85
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Detectability of Local Lesions in the Heart using Echo Planar versus Spiral Hyperpolarized 13C Imaging |
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland |
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Spiral and EPI are the most commonly used trajectories for imaging hyperpolarized 13C substrates. In this work, the two acquisition methods are compared with regard to B0 and T2* effects for typical parameter sets used for in vivo imaging of the heart. While Spirals exhibit higher SNR, EPI trajectories show higher effective resolution with standard gradient system performance. The relative differences in SNR and resolution between the two trajectories reduce with the availability of high-performance gradients. |
| 4286 | Computer 86
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Polarisation, T1 and Synthetic Impurities in Hyperpolarised Acetoacetate: Density Functional Theory to In Vivo Application |
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom, 2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 3Oxford Centre for Clinical Cardiac Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom, 4Department of Chemistry, University of Oxford, Oxford, United Kingdom, 5University Hospitals Bristol NHFS Foundation Trust, Bristol, United Kingdom, 6Department of Physics, University of Oxford, Oxford, United Kingdom |
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Alterations in ketone body metabolism are implicated in disease. Several studies have observed metabolism in hyperpolarised sodium acetoacetate, but as a hyperpolarised probe it has a short T1 (28s at 7T), limiting polarisation of 7-8%, and is often chemically impure as it spontaneously decarboxylates at neutral pH at 300K. We have studied selective deuteration of [1-13C] and [1,3-13C]acetoacetate together and evaluated the effect of salt solvation on hyperpolarisation in the discretised Borghini model of thermal mixing. Li+[2,2-2H2,1,3-13C2]acetoacetate is observed to have a higher limiting polarisation and substantially longer T1 than Na+[1-13C]acetocetate. |
| 4287 | Computer 87
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A 3D HYBRID-SHOT SPIRAL FOR HYPERPOLARIZED 13 C IMAGING (3D-HYSS) |
1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 2Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Oxford, United Kingdom, 3Department of Physics, University of Oxford, Oxford, United Kingdom |
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Spiral k-space trajectories are a powerful tool for in vivo 13C hyperpolarized cardiac MRI, however short readout durations limit the maximum resolution that single-shot spiral trajectories can achieve for a given field of view. This leaves the researcher with a choice at acquisition time, use a single-shot trajectory with poor spatial resolution or switch to a multiple-shot scheme with improved spatial resolution at the cost of degraded temporal resolution. We present a hybrid-shot spiral trajectory, which by compounding a single-shot and multiple-shot spiral, shifts this decision to analysis time. |
| 4288 | Computer 88
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Data-driven Nyquist ghost correction for hyperpolarized 13C EPSI and EPI |
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Department of Neurology, University of New Mexico, Albuquerque, NM, United States, 3Department Physics and Astronomy, University of New Mexico, Albuquerque, NM, United States, 4Department Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States, 5Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Technical University of Denmark, Lyngby, Denmark, 6Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark, 7Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 8Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Echo-planar readout is often used in hyperpolarized imaging because of its rapid sampling of the k-space. This scheme, however, suffers from Nyquist ghosting artifacts. We present a data-driven approach to correct Nyquist ghosting in hyperpolarized 13C-EPSI and EPI . The method exploits the sparsity of the spectra in hyperpolarized 13C imaging spectroscopy, and estimates the phase discrepancies from the odd and even data in 13C-EPSI. The method was demonstrated in phantoms and in vivo. We show that it performs better than the 1H reference-based reconstruction, and it eliminates the need for reference scans, which may be an unnecessary source of error. |
| 4289 | Computer 89
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Binomial Excitation for Detection of Hyperpolarized [2-13C]Dihydroxyacetone Metabolism |
1Biochemistry and Mol. Bio., University of Florida, Gainesville, FL, United States, 2Imaging Physics, MD Anderson Cancer Center, Houston, TX, United States |
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In this study, we have employed a simple binomial excitation pulse to follow metabolism of hyperpolarized [2-13C]dihydroxyacetone in perfused livers. We demonstrate the utility of binomial pulses in suppressing the hyperpolarized (HP) substrate resonance and maximizing metabolite signal intensities. |
| 4290 | Computer 90
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Partial hyperpolarization transfer to protons in [15N2]urea |
1Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, 2Department of Radiology, Hebrew University of Jerusalem, Jerusalem, Israel, 3Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom |
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Direct observation of 15N hyperpolarization is limited by nitrogen’s low gyromagnetic ratio. We overcome this limitation here by transferring 15N hyperpolarization in [15N2]urea to spin coupled protons. The larger gyromagnetic ratio of the protons will increase the sensitivity of detection provided that there is not a significant loss of polarization during the transfer. We show that our polarization transfer pulse sequence, which has been modified for partial polarization transfer, is tolerant of B1 and centre frequency variations and can be used for dynamic spectroscopy and imaging measurements. |
| 4291 | Computer 91
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Making the Transfer: Exploiting Hyperpolarized Bicarbonate-CO2 Exchange for Increased Signal-to-Noise pH Imaging |
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Bioengineering, University of California, Berkeley and University of California, San Francisco, San Francisco, CA, United States |
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Hyperpolarized (HP) [13C]bicarbonate MR imaging can map pH in vivo, but images generally suffer from low CO2 signal-to-noise ratio (SNR). However, rapid bicarbonate-CO2 chemical exchange can increase CO2 SNR via exchange-mediated polarization transfer. We exploit this phenomenon for HP [13C]bicarbonate imaging to boost CO2 SNR by 2.2-fold at pH 7.6, where CO2 SNR is lowest in the physiologic range, by acquiring and summing multiple transients. Tip angles and delays are chosen using a priori knowledge of exchange rate to increase SNR while mitigating pH error. This approach can potentially improve imaging SNR in vivo for studying extracellular acidosis in cancer. |
| 4292 | Computer 92
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Multi-Slice Correction for Metabolic Rate Quantification of Hyperpolarized Pyruvate |
1Imaging Physics, MD Anderson Cancer Center, Houston, TX, United States |
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Due to the non-renewable nature of |
| 4293 | Computer 93
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Quadrature Transmit and Receive Array 13C RF Coil for Clinical Cardiac and Hepatic Imaging with Hyperpolarized 13C-Substrates |
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Electrical and Computer Engineering, University of Texas Dallas, Richardson, TX, United States, 4Clinical MR Solutions, Brookfield, WI, United States, 5GE Healthcare, Dallas, TX, United States, 6GE Healthcare, Toronto, ON, Canada, 7Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States |
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A flexible torso 13C RF coil with quadrature transmit and 8-channel receive array that is designed for imaging cardiac and hepatic metabolism in humans was evaluated. B1+ field homogeneity and SNR were measured using phantoms. The torso coil had improved SNR and larger spatial coverage as compared to the conventional clamshell/paddle array coils. |
| 4294 | Computer 94
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Improving Hyperpolarized 13C Spiral Chemical Shift Imaging Using Model-Based Iterative Reconstruction and Prior Knowledge |
1Diagnostic Radiology & Nuclear Medicine, University of Maryland Baltimore, Baltimore, MD, United States |
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A model-based iterative reconstruction algorithm for spiral chemical shift imaging (spCSI) of hyperpolarized 13C metabolites is implemented and compared to conventional CSI reconstruction. The iterative reconstruction utilizes the prior knowledge of 1) the off-resonance frequencies for each metabolite and 2) the common spatial distribution for pyruvate and pyruvate hydrate. The proposed method improves quantification of bicarbonate and reduces artifacts for pyruvate maps caused by |
| 4295 | Computer 95
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Apparent metabolic exchange rate mapping using saturation-recovery acquisition and Michaelis-Menten modelling |
1GE Healthcare, Munich, Germany, 2MR Research Centre, Aarhus University, Aarhus, Denmark |
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Injecting high doses of hyperpolarised 13C pyruvate in vivo leads to saturation effects: more precursor will not increase the amount of downstream substrate, leading to errors when quantifying with the conventional two-site exchange model. Saturation effects can be modelled via a Michaelis-Menten kinetics, however requiring metabolic exchange rates measured at multiple time points as input. In this work we extend a previous saturation-recovery measurement to map apparent metabolic exchange rates taking saturation effects into account. |
| 4296 | Computer 96
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Symmetry Preserved Rectilinear Transform(SPRT): Optimized Reconstruction of Echo Planar Spectroscopic Image for Hyperpolarized [1-13C]-Pyruvate |
1Imaging Physics, UT MD Anderson Cancer Center, Houston, TX, United States |
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A new reconstruction method, symmetry preserved rectilinear transform (SPRT) is proposed to remove the Nyquist ghost and chemical shift artifacts from symmetric echo-planar spectroscopic imaging (EPSI) data. For each metabolite in the spectrum, an additional phase term is added to reshape the zig-zag layout of k-t space samples into a rectilinear layout with all echoes parallel to each other in k-t space. SPRT can eliminate artifacts and significantly improve SNR. |
| 4297 | Computer 97
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Frequency calibration methods for the use of 13C spectral-spatial pulses in human brain |
1Dept of Radiology, University of Cambridge, Cambridge, United Kingdom, 2Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, 3MR Research Centre, University of Aarhus, Aarhus, Denmark, 4GE Healthcare, Munich, Germany |
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Spectral-spatial pulses demand accurate frequency setting, which is difficult for studies using hyperpolarized 13C substrates, as the calibration has to be performed prior to the injection of the labelled molecule. In this study we retrospectively analysed human 13C brain studies, comparing three methods of scan calibration: study date, external reference phantom, and 1H frequency. The latter method outperformed the other 2 by a large margin: the SD of differences (predicted minus actual frequency of pyruvate) was 11 Hz with 1H frequency, 39 Hz using study date, and 40 Hz when referenced to an external phantom. |
| 4298 | Computer 98
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Fast acquisition of hyperpolarized MR with Multi-echo EPI |
1Radiology & Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Weill Cornell Medical College, New York, NY, United States |
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An EPI acquisition can efficiently acquire data, allowing multiple images to be acquired before the transverse signal decays due to T2*. These images (acquired at different echo times) can be reconstructed into images of individual species, as with Dixon or IDEAL. This approach can be used to efficiently acquire hyperpolarized data by limiting the number of excitations to preserve longitudinal magnetization for subsequent time points or enabling the use of larger flip angles for higher SNR. In this abstract, we demonstrate the feasibility of this approach with thermal phantoms (acetate, alanine, and urea) and with hyperpolarized phantoms (pyruvate and urea). |
| 4299 | Computer 99
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A Quadrature Detection Technique to Resolve J-Modulated [2-13C]Lactate in Hyperpolarized [2-13C] Pyruvate Imaging |
1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States |
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For the imaging of hyperpolarized [2-13C]pyruvate, we propose a hybrid approach in which the closely spaced metabolic peaks of pyruvate, glutamate, citrate, acetoacetate, and acetyl-carnitine are measured using spectroscopic imaging, while the highly shifted [2-13C]Lactate peak is measured using selective excitation with a conventional fast imaging readout. We further demonstrate that a quadrature image reconstruction algorithm combining data from two fast imaging acquisitions, with the readout shifted by 1/2J, eliminates severe artifacts that normally arise when imaging a J-coupled system for which 1/J is comparable to the readout window. |
| 4300 | Computer 100
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Spiral-IDEAL for Time-Resolved Imaging of Hyperpolarized 129Xe Kinetics in the Rat Brain |
1Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Department of Medical Imaging, University of Toronto, Toronto, ON, Canada |
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Rapid, spectrally resolved imaging of 129Xe in the rat brain may allow for measurement of cerebral blood flow, as well as tissue characteristics such as relaxation rates and partition coefficient which may be useful for characterizing neurological disease or injury such as stroke. In this work, the feasibility of spiral-IDEAL for spectrally resolved 129Xe in the rat brain was demonstrated during steady state ventilation of a rat. With future improvements to the signal-to-noise ratio, it is proposed that spiral-IDEAL will allow for rapid, spectrally resolved imaging of the brain. |
| 4301 | Computer 101
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Detection of pyruvate carboxylation and age related changes in glycolysis in human brain using hyperpoplarized 13C MR spectroscopy |
1GE Healthcare, Toronto, ON, Canada, 2Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 3Medical Biophysics, University of Toronto, Toronto, ON, Canada, 4Pharmacy, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 5Sunnybrook Health Sciences Centre, Toronto, ON, Canada |
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The feasibility of acquiring hyperpolarized 13C images from human brains following injections of HP [1-13C]pyruvate solution has been recently demonstrated. In this study, following each dynamic 3D volume 13C imaging acquisition (5 s temporal resolution), 13C spectroscopic data were acquired from a large slab through the brain. 13C pyruvate, lactate, alanine and bicarbonate were observed in all volunteer subjects. 13C aspartate was also detect in some of the subjects. Good inter-subject consistency in metabolite ratios as well as potential age related trend were observed in these data. |
| 4302 | Computer 102
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Lactate production but not pool-size is altered in infiltrative mouse model of human GBM: a 1H MRS and hyperpolarized [2H7,13C6]D-glucose study |
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Department of Clinical Neuroscience, Lausanne University Hospital, Lausanne, Switzerland, 3Department of Radiology, University of Geneva (UNIGE), Geneva, Switzerland, 4Department of Radiology, University of Lausanne (UNIL), Lausanne, Switzerland, 5Centre d'Imagerie Biomédicale (CIBM), École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland |
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Glioblastoma (GBM) is the most malignant primary brain tumor in adults. Aberrant glucose metabolism is considered a hallmark of cancer, via the so called ‘Warburg Effect’. MRS gives the access to study tumor metabolism. 1H MRS enables to quantify the steady state pool size and 13C MRS of hyperpolarized (HP) endogenous compounds provides real time metabolic information which is related to enzymatic activity. The aim of the present study was to examine whether changes in lactate production through glycolysis can be characterized using HP [2H7,13C6]D-glucose MRS, and if those correspond to changes in lactate pool size. |
| 4303 | Computer 103
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In-Vivo Metabolism Differences of Multiple Body Parts using Hyperpolarized [2-13C]pyruvate |
1UT Southwestern Meidcal Center, Dallas, TX, United States |
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Hyperpolarized [2-13C]-pyruvate can assess multiple metabolic pathways within mitochondria to follow the 13C label beyond flux through PDH complex and investigate the incorporation of acetyl-coenzyme into different metabolic pathways. This study investigated metabolic products from [2-13C]-pyruvate and the differences of LDH and ATL process in heart, liver and kidney. |
| 4304 | Computer 104
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Differentiating Radiation Necrosis from Brain Tumor Using Hyperpolarized Carbon-13 Metabolic MRI |
1Radiology, Chonnam National University Hwasun Hospital, Hwasun, Korea, Republic of, 2Radiology, Chonnam National University Medical School and Hospital, Gwangju, Korea, Republic of, 3Radiation Oncology, University of California San Francisco, San Francisco, CA, United States, 4Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, Bethesda, MD, United States, 5Neurosurgery, Chonnam National University Hwasun Hospital, Hwasun, Korea, Republic of |
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The differentiation of recurrent tumor from radiation necrosis after radiation therapy remains often challenging in patients with brain tumor despite various advanced MR imaging techniques. The purpose of this study was to explore the feasibility of hyperpolarized 13C metabolic imaging in differentiating brain tumor from radiation necrosis. The lactate signal in radiation necrosis model was significantly lower than that in glioma and lung cancer metastasis. This suggests that the non-invasive characterization of real-time metabolism using this new neuroimaging method may be helpful for differentiating radiation-induced necrosis from recurrent brain tumors. |
| 4305 | Computer 105
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Distinguishing metabolic signals of liver tumors from surrounding liver cells using hyperpolarized 13C MRI and Gadoxetate |
11Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 2Liver Center, University of California, San Francisco, CA, United States |
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Hyperpolarized (HP) 13C MRI is a new technique that can assess the metabolic pathways in a variety of tumors. In this study, we show the ability of a gadolinium-based contrast agent (gadoxetate) to selectively suppress the HP metabolic signal arising from normal hepatocytes by altering the relaxation rates of metabolites 13C pyruvate and 13C lactate in order to evaluate the metabolic profile of tumors within the liver. |
| 4306 | Computer 106
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Rapid Visualization of the Effects of Lactate Dehydrogenase Inhibition in Breast Cancer using Hyperpolarized Pyruvate |
1Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 2Hematology/Oncology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 3Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States |
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High rates of glycolysis in cancer can be targeted by inhibition of lactate dehydrogenase (LDH), the enzyme responsible for conversion of pyruvate into lactate. Hyperpolarized pyruvate was employed to assess the effects of GNE140, a recently developed inhibitor of LDH. Administration of GNE140 results in a sizable reduction in lactate signal within 30 minutes of administration. |
| 4307 | Computer 107
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Pyruvate dehydrogenase kinase knockout restores hepatic pyruvate oxidation in STZ-induced diabetic mice as revealed by hyperpolarized 13C-MRI |
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States, 4Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 5Department of Chemistry, University of Texas at Dallas, Richardson, TX, United States |
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Pyruvate dehydrogenase (PDH) kinase (PDK) modulates mitochondrial oxidative metabolism of carbohydrate by phosphorylating and inhibiting PDH. PDK is, therefore, an important therapeutic target for treating and managing metabolic diseases. This study evaluated |
| 4308 | Computer 108
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Probing multiple metabolic pathways in vivo with 1H-decoupled 13C-MRS of hyperpolarized [2-13C]dihydroxyacetone |
1Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain, 2Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, 3Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 4Oxford Centre for Clinical Cardiac Magnetic Resonance Research, John Radcliffe Hospital, Headington, United Kingdom, 5Department of Physics, University of Oxford, Oxford, United Kingdom, 6General Electric Healthcare, Chalfont St Giles, United Kingdom |
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Hyperpolarized [2-13C]dihydroxyacetone is a promising probe to investigate changes in glucose metabolism in different metabolic states, such as the alterations caused by diabetes or non-alcoholic fatty liver disease. Proton decoupled 13C-MR spectra of hyperpolarized [2-13C]dihydroxyacetone (DHAc) were acquired from the mouse liver using specialized spectral-spatial RF pulses. This optimized protocol for in vivo studies revealed metabolic products from three different metabolic pathways (gluconeogenesis, glycolysis and lipid synthesis) following the injection of this single hyperpolarized substrate. The metabolic products detected include glycerol 3-phosphate, glycerol, phosphoenolpyruvate, lactate, alanine, glyceraldehyde 3-phosphate and glucose 6-phosphate. |
| 4309 | Computer 109
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Detecting early response to PD-L1 blockade by 13C MRI |
1Radiation Biology Branch, National Cancer Institute, Bethesda, MD, United States |
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This goal of this study is to detect metabolic changes using hyperpolarized 13C-MRI with [1-13C] pyruvate to evaluate the response to PD-L1 blockade treatment. Lactate/Pyruvate ratio tended to decrease in αPD-L1 antibody treated tumor in mouse model although not statistically significant. We will investigate capability of metabolic imaging to early response to immune checkpoint inhibitor. |
| 4310 | Computer 110
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Hyperpolarised [1-13C]pyruvate imaging of response to Bevacizumab |
1Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, 2CRUK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom |
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13C chemical shift images were obtained from orthotopic rat models of glioblastoma prior to and following treatment with Bevacizumab. The resulting change in the hyperpolarized [1-13C]lactate/[1-13C]pyruvate ratio differed depending upon the model used. In U87 tumors the ratio increased and in patient-derived xenografts it decreased, with long term treatment of this latter model producing an invasive phenotype. |
| 4311 | Computer 111
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Feasibility and Reproducibility of Imaging Brain Metabolism Using Hyperpolarized 13C Pyruvate in Humans |
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Electrical and Computer Engineering, University of Texas Dallas, Richardson, TX, United States, 4GE Healthcare, Dallas, TX, United States, 5University of Texas Southwestern Medical Center, Dallas, TX, United States, 6University of Maryland, Baltimore, Baltimore, MD, United States, 7Clinical MR Solutions, Brookfield, WI, United States, 8Neurosurgery, University of Texas Southwestern Medical Center, Dallas, TX, United States, 9Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States |
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Human brain metabolism was investigated using hyperpolarized [1-13C]pyruvate and [2-13C]pyruvate in vivo. Each subject received hyperpolarized pyruvate intravenously with a 45-min interval between the injections. [1-13C]lactate and [13C]HCO3– were consistently detected from hyperpolarized [1-13C]pyruvate. [5-13C]Glutamate was measured from hyperpolarized [2-13C]pyruvate. The levels of production and relative intensities of the 13C-labeled metabolites were reproducible. |
| 4312 | Computer 112
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Cardiac metabolic imaging using hyperpolarized [1-13C]lactate as a substrate |
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada |
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The use of hyperpolarized [1-13C]lactic acid as a substrate for studying cardiac metabolism is attractive due to its high safety profile. 13C metabolite images were acquired following injection of hyperpolarized [1-13C]lactate in the porcine heart. The appearance of 13C-bicarbonate and absence of 13C-pyruvate in these images demonstrates rapid decarboxylation of pyruvate within the cardiac tissue. |
| 4313 | Computer 113
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Effect of Opening the Blood-Brain Barrier with Focused Ultrasound on 13C Hyperpolarized Imaging in Rat Brain |
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Radiology, Stanford University, Stanford, CA, United States, 4Chemistry and Biochemistry, California State University Fullerton, Fullerton, CA, United States, 5Electrical and Computer Engineering, University of Texas Dallas, Richardson, TX, United States |
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We examined how opening the blood-brain barrier (BBB) with focused ultrasound (FUS) pulses changes the uptake and metabolism of hyperpolarized [1-13C]pyruvate and [1-13C]glycerate in the brain. We observed larger amounts of metabolic products, lactate and bicarbonate, from hyperpolarized [1-13C]pyruvate in the brain region where FUS was applied. Moreover, increased [1-13C]glycerate uptake in the brain was detected after the FUS-induced BBB opening. |
| 4314 | Computer 114
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Hyperpolarized 13C MRI Cellular Transport Modeling |
1School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States |
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Hyperpolarized (HP) 13C MRI is very appealing due to its potential in imaging the dynamic metabolic conversion and transport process. In this work, we tried to model the cellular transport process for dynamic HP 13C studies. Two highlights in this work are, (1) separating intra- and extracellular HP [1-13C] lactate based on dynamic HP 13C diffusion weighted imaging (DWI) technique, (2) extending standard kpl model to quantify cellular transport, with applications to cancer cell studies and cancer mouse studies. |
| 4315 | Computer 115
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Hyperpolarized 5-13C-Glutamate metabolism as a biomarker of IDH1 mutant glioma response to temozolomide therapy |
1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 2Department of Neurological Surgery, Helen Diller Research Center, University of California San Francisco, San Francisco, CA, United States, 3Brain Tumor Research Center, University of California San Francisco, San Francisco, CA, United States |
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The alkylating agent temozolomide (TMZ), previously used only in the treatment of high-grade glioblastoma, is now being considered for the treatment of low-grade glioma that are driven by mutations in the cytosolic isocitrate dehydrogenase 1 (IDH1) gene. However, early detection of response remains a challenge. 1H and hyperpolarized 13C magnetic resonance spectroscopy-based metabolic profiling of cells genetically engineered to express mutant IDH1 and treated with TMZ showed significant alterations in metabolites majorly related to the tricarboxylic acid cycle, and identified hyperpolarized 5-13C-glutamate metabolism as an indicator of response. These findings hold potential for assessing response of IDH1 mutant cells to TMZ therapy. |
| 4316 | Computer 116
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Investigating the Impact of Hypoxia on Lung Metabolism using Hyperpolarized Carbon-13 MRSI |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States |
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Systemic hypoxemia is a clinical hallmark of many lung pathologies, yet its impact on lung metabolism is not well understood. In this hyperpolarized carbon-13 MRI study, we seek to demonstrate the impact of both moderate and severe systemic hypoxemia on lung pyruvate metabolism using an imaging approach. |
| 4317 | Computer 117
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Quantification of In Vivo Saturation Kinetics of Co-Polarized [2-13C]Pyruvate and [1,4-13C2]Fumarate in Rat Liver Using Dynamic 3D-Spiral CSI with Alternate Spectral Band Excitation |
1Diagnostic Radiology and Nuclear Medicine, University of Maryland Baltimore, Baltimore, MD, United States |
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Dynamic metabolic imaging of co-polarized 13C-labeled pyruvate (Pyr) and fumarate (Fum) has shown great potential in characterizing multiple in vivo metabolic activities as demonstrated in recent animal models.1,2 Although in these studies, both the injected substrates and downstream metabolic product can be acquired over time at relatively high spatial resolution, robust quantification and metabolic modelling remains an active area of investigation. Also, the enzyme saturation effects that are routinely seen with commonly used doses of hyperpolarized substrates are not correctly captured using approaches such as metabolite ratios, time-to-peak of metabolic products, single exchange rate constants and by constant small-flip-angle excitation. Therefore, the goal of this study is to measure the saturation kinetics of various involved enzymatic processes using effective 90° excitation of the products at clinical field strengths. This work is an extension of our method developed for dynamic metabolic imaging of co-polarized mixture of [2-13C]Pyr and [1,4-13C2]Fum.2 |
| 4318 | Computer 118
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Hyperpolarized Dihydroxyacetone Metabolism in the Mouse Liver Under Physiological Perfusion Conditions |
1Biochemistry and Mol. Bio., University of Florida, Gainesville, FL, United States, 2Imaging Physics, MD Anderson Cancer Center, Houston, TX, United States |
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Hyperpolarized [2-13C]dihydroxyacetone is a promising new molecular imaging agent that is sensitive to hepatic gluconeogenesis as well as glycolytic flux. Here, a physiological perfusion condition produces a metabolic profile in keeping with current understanding of hepatic metabolism, as compared to previous results from a model intended to strongly upregulate gluconeogenesis. |
| 4319 | Computer 119
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Per-deuteration does not affect metabolic rates of hyperpolarized pyruvate in the isolated heart |
1UT Southwestern Medical Center, Dallas, TX, United States, 2UT Dallas, Richardson, TX, United States, 3Veterans Affairs North Texas Healthcare System, Dallas, TX, United States |
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The effects of deuteration in pyruvate on conversion to alanine and lactate, and flux into the TCA cycle were investigated by 13C NMR of tissue extracts from isolated hearts and studies of hyperpolarized [1-13C1, 3,3,3-2H3]pyruvate. No kinetic isotope effects were noted, but substantial exchange of water protons with deuterium was observed in alanine but not lactate or glutamate. Deuteration of pyruvate had little effect on metabolism in heart tissue, and the data suggests that formation of a Schiff base in alanine transaminase may occur without net interconversion of pyruvate and alanine. |
| 4320 | Computer 120
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Flow attenuation and saturation-recovery to discriminate between intracellular and inflowing species in renal hyperpolarized 13C MRS |
1Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Department of Radiology, University of Geneva (UNIGE), Geneva, Switzerland, 3Department of Radiology, University of Lausanne (UNIL), Lausanne, Switzerland |
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Selective attenuation of signal from flowing hyperpolarized 13C spins can be used to enhance the fraction of signal from locally-produced metabolites. Here, we look at the effect of flow attenuation in the rat kidney on pyruvate metabolite ratios using an interleaved pulse-acquire/spin-echo+bipolar gradient acquisition scheme. With flow-sensitizing gradients applied, lactate- and alanine-to-pyruvate ratios increase as anticipated. Unexpectedly, the ratio of the hydrate and keto forms of pyruvate increases as well, suggesting a greater fraction of flowing keto-pyruvate. The increasing lactate signal fraction after saturation indicates that labelled circulating lactate becomes predominant over the course of the acquisition. |
| 4321 | Computer 121
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Ex-vivo investigation of renal metabolic heterogeneity using hyperpolarized [1-13C]pyruvate MRI: a novel renal perfusion device |
1Department of Clinical Medicine, the MR Research Centre, Aarhus University, Aarhus N, Denmark, 2Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark, 3Department of Anesthesia and Intensive Care, Aarhus University Hospital, Aarhus N, Denmark |
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The mammalian kidney is a complex organ, maintaining the water and nutrient balance of the body. Current knowledge of the essential functions, and the interplay with metabolic processes, are mainly derived from small animal experiments (uni-papilary kidneys) using invasive methods and lacking spatial resolution. The approach presented here addresses these limitations, by introducing a new MR compatible kidney perfusion device, enabling imaging of the underlying metabolic and functional patterns associated with the multi-papillary porcine kidney, better resembeling the human physiology. |
| 4322 | Computer 122
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Non-invasive detection of toxin-induced inflammation in the mouse brain using hyperpolarized 13C MRSI |
1Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, CA, United States, 2Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States |
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In recent years, hyperpolarized (HP) 13C magnetic resonance spectroscopic imaging (MRSI) has shown promise in assessing neuroinflammation in the brains of mouse models of multiple sclerosis and traumatic brain injury. In this follow-up study, we used 13C MRSI of HP [1-13C] pyruvate/13C urea to assess neuroinflammation following intracranial injection of a toxin, namely lipopolysaccharide (LPS). A significantly elevated lactate:pyruvate ratio was observed in LPS-injected mice, and was associated with a significant increase in the presence of macrophages/microglia and astrocytes as assessed histologically. Our results demonstrate that HP 13C MRS has the sensitivity to assess toxin-induced changes in the brain. |
| 4323 | Computer 123
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Metabolism of hyperpolarized [1-13C]pyruvate in isolated perfused kidneys |
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States |
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Kidney primarily oxidizes fatty acids and ketone bodies for ATP production but the substrate preference is altered in metabolic diseases. Renal metabolism is generally evaluated in kidney slices and in vivo. However, real-time metabolism has not been studied in isolated perfused kidneys where substrate availability and pharmacological interventions can be well-controlled. Here, we investigate pyruvate metabolism in isolated perfused rat kidneys by hyperpolarized 13C NMR. Results show that hyperpolarized 13C-pyruvate was rapidly metabolized in the kidneys and productions of 13C-bicarbonate, 13C-alanine, and 13C-lactate were detected. the utilization of pyruvate for energy production was confirmed by isotopomer analyses of tissue extracts. |
| 4324 | Computer 124
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Mitochondrial redox imaging of NASH animal model using in vivo Dynamic Nuclear Polarization MRI |
1Gifu University, Gifu, Japan, 2Kyushu University, Fukuoka, Japan, 3Japan Redox Inc., Fukuoka, Japan |
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Currently available non-invasive imaging technologies, including CT, MRI and ultrasonography, are only able to assess fat accumulation in the liver. Therefore, these methods are not suitable for a precise diagnosis of NASH. The standard technique for diagnosing NASH, liver biopsy, has several drawbacks, such as the higher risk of complications that accompanies invasive procedures. Here, we demonstrated that in vivo mitochondrial redox metabolism was dramatically altered at an early stage, and NASH could be accurately diagnosed by in vivo dynamic nuclear polarization-magnetic resonance imaging, with carbamoyl-PROXYL as a molecular imaging probe. In addition, this technique was feasible for distinguishing between NAFLD and NASH. Our data reveal a novel method for monitoring the dynamics of redox metabolic changes and assessing the efficacy of therapeutic agents in NAFLD/NASH. |
| 4325 | Computer 125
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Research Polarizer Quality Control Metrics and Resulting SNR in Human Prostate Cancer Patients |
1Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, United States, 2The Graduate Group in Bioengineering, University of California at Berkeley and San Francisco, San Francisco, CA, United States, 3Department of Urology, University of California at San Francisco, San Francisco, CA, United States, 4Department of Pathology, University of California at San Francisco, San Francisco, CA, United States |
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The number of sites performing hyperpolarized [1-13C]pyruvate human studies is increasing every year. We relate metrics used in quality control (QC) of a polarized sample to traditional metrics of signal quality in vivo in 24 hyperpolarized human prostate exams. The QC metrics of injected volume and injection time are significantly correlated with the maximum [1-13C]pyruvate SNR in vivo (r=0.68, p<0.01; r=-0.48,p=0.05, respectively) and the number of voxels with estimated usable SNR (r=0.70, p<0.01; r=-0.59, p=0.01, respectively). These metrics have improved over the course of this trial with team coordination and can be improved at other sites beginning hyperpolarized human research. |
| 4326 | Computer 126
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Improved attenuation correction for cardiac 18F-FDG PET/MR hybrid imaging |
1High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, 3Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg Essen, Essen, Germany |
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The aim of this study was to evaluate and quantify the effect of improved attenuation correction including bone segmentation and truncation correction on 18F-FDG cardiac PET/MR imaging. Therefore, 32 cardiac patient data sets were reconstructed with different AC-maps and polar plots were generated and analyzed. The MR-based HUGE method for truncation correction combined with CT model-based bone segmentation resulted in a homogeneous 6% gain of PET signal across the myocardium compared to standard Dixon-VIBE imaging. The majority of observed AC-map artifacts did not significantly affect the quantitative assessment of the myocardium. |
| 4327 | Computer 127
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Cancer screening using 18F-FDG PET/MR in asymptomatic subjects: a preliminary report |
1Universal Medical Imaging, Shanghai, China, 2MR collaboration, Diagnostic Imaging, Siemens Healthcare, Shanghai, China, 3MR Scientific Marketing, Diagnostic Imaging, Siemens Healthcare, Beijing, China |
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This study was performed to evaluate the diagnostic value of PET/MR for cancer screening in asymptomatic subjects. 1491 subjects in total were enrolled in this study. 33 cases were diagnosed with malignant tumors, whereas 17 cases were correctly detected by PET/MR and 16 cases were detected by other methods. The overall detection rate of PET/MR in asymptomatic subjects was 1.14%, and the sensitivity, specificity, positive predictive value, and negative predictive value of PET/MR were 51.52%, 99.66%, 77.27% and 98.91%, respectively. As a cancer screening method, FDG PET/MR has great potentials to detect various kinds of tumors and should be beneficial to combine with other screening modalities. |
| 4328 | Computer 128
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Hybrid Rectal Multiparametric F18-FDG PET/MR in Restaging Locally Advanced Rectal Cancer: An initial experience |
1Radiology, Mayo Clinic Arizona, Scottsdale, AZ, United States, 2Surgery, Mayo Clinic Arizona, Scottsdale, AZ, United States, 3Radiation Oncology, Mayo Clinic Arizona, Scottsdale, AZ, United States |
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Rectal cancer is a leading cause of cancer death in the United States. Current standard of care in locally advanced rectal cancer includes chemoradiation therapy followed by surgical resection. Accurate radiological restaging therapy is essential for success of surgery. In this preliminary study, we investigated the synergistic role of rectal mpMRI and F18-FDG PET/MR in evaluation of response to therapy in advanced rectal cancer. Our data show promising added value of this “one-stop” imaging modality in providing complementary morphological and functional information in the detection of viable primary tumor as well as nodal and distal metastases, utilizing both MRI and PET molecular imaging biomarkers. |
| 4329 | Computer 129
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Joint estimation of activity and attenuation using 68Ga-PSMA TOF PET/MR in patients with hip endoprosthesis |
1Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland, 2University of Zurich, Zurich, Switzerland, 3GE Global Research, Niskayuna, NY, United States, 4GE Healthcare, Munich, Germany, 5GE Healthcare, Waukesha, WI, United States |
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Accurate PET attenuation correction remains challenging in PET/MR. Skeletal bone is usually not included and metal implants can cause serious artifacts. In this study we investigate the application of the ‘joint estimation of activity and attenuation’ PET reconstruction algorithm, using MR based priors, in prostate cancer patients with metal hip implants who were scheduled for 68Ga-PSMA TOF PET/MR. The results indicate that, even with the low background-signal of this tracer, the JE algorithm can recover most of the metal hip implant(s), thereby potentially improving the PET attenuation map as well as the activity images. |
| 4330 | Computer 130
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Dose minimization in the detection of supraclavicular brown adipose tissue in 18F-FDG TOF-PET/MR: a simulation study |
1Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland, 2University of Zurich, Zurich, Switzerland, 3Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland, 4Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland, 5Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland, 6University of Basel, Basel, Switzerland |
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An increasing number of prospective trials are investigating the activity of brown adipose tissue (BAT) with 18F-FDG PET, in patients as well as in healthy volunteers. According to the Brown Adipose Reporting Criteria in Imaging Studies (BARCIST 1.0) the injected dose of 18F-FDG should be as low as possible, for statistically valid imaging, with consideration for total dosage in repeat studies. In our 18F-FDG TOF PET/MR simulation study we found that a minimum injected dose of 15MBq (0.29mSv) still allowed for accurate quantification of BAT activity, without a significant increase in noise or artifacts. |
| 4331 | Computer 131
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Spatio-Temporal Association Between Simultaneously BOLD and FDG Resting State Networks |
1Monash Biomedical Imaging, Monash University, Clayton, Australia, 2Department of Electrical and Computer System Engineering, Monash University, Clayton, Australia, 3Monash Institute for Cognitive and Clinical Neuroscience, Monash University, Clayton, Australia, 4Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne, Australia |
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The slow-infusion-based dynamic FDG-PET have demonstrated excellent sensitivity to glucose uptake in the brain. Using fPET which contains unprecedented temporal information, we introduce a cross-modality spatiotemporal regression method to measure the association of resting net works (RSNs) between simultaneously acquired fMRI and fPET datasets. By projecting both temporal and spatial information in RSNs from two modalities into the proposed cross-modality association index, several associated networks have been identified by the proposed method. |
| 4332 | Computer 132
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A Carotid Artery Image-Derived Input Function for Pre-Clinical Simultaneous PET/MRI |
1Medical Biophysics, Western University, London, ON, Canada, 2Lawson Imaging, Lawson Health Research Institute, London, ON, Canada |
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Using the carotid arteries for the extraction of an image-derived input function for kinetic modelling in rats. |
| 4333 | Computer 133
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Flexible Numerical Simulation Framework for Dynamic PET-MRI |
1Physikalisch-Technische Bndesanstalt (PTB), Braunschweig and Berlin, Germany, 2Institute of Nuclear Medicine, University College London, London, United Kingdom, 3Scientific Computing Department, Science and Technology Facilities Council, RAL, Didcot, United Kingdom, 4Centre for Medical Imaging, University College London, London, United Kingdom, 5School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom |
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A numerical simulation framework for dynamic simultaneous PET- MR is presented, which allows for simulated data acquisition of different anatomy with cardiac and respiratory motion and dynamic contrast changes (due to MR contrast agent or PET tracer changes over time). The output of the simulation framework is provided in ISMRMRD and PET interfile raw data format and can be directly used in a range of available reconstruction packages. The reconstructed PET and MR images of the simulated data were compared to an in-vivo patient scan demonstrating that the simulation framework yields realistic data. |
| 4334 | Computer 134
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The Value of PET/MR Multimodality Imaging in Assessing Intratumoral Biological Heterogeneity in Patients with Lung Cancer |
1Department of Nuclear Medicine, Chinese PLA General Hospital, Beijing, China, 2Department of Radiology, Chinese PLA General Hospital, Beijing, China, 3MR Collaboration, Diagnostic Imaging, Siemens Healthcare Ltd, Shanghai, China |
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Lung cancer is characterized by high intra-tumoral heterogeneity, which potentially increases the difficulties of obtaining accurate biopsy results. By combining CT guided-biopsy of lung masses with previously acquired PET/MR images, we investigated the pathological statuses and gene mutation of tissues samples from different locations within one tumor. The results demonstrated that PET/MR can increase the accuracy of a biopsy as well as enhance our understanding of the complicated biological behaviors of cancers. |
| 4335 | Computer 135
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Motion-corrected simultaneous DCE-MRI and PET for hepatic lesion assessment |
1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, 2Department of Radiology, Charité, Berlin, Germany, 3Department of Nuclear Medicine and BERIC - Berlin Experimental Radionuclide Imaging Center, Charité, Berlin, Germany |
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Dynamic contrast enhancement (DCE) MRI is an important clinical imaging tool to characterize hepatic tumors. Especially in combination with PET imaging data, it has been shown to improve diagnostic confidence compared to PET/CT. Nevertheless, respiratory motion is still challenging, requiring multiple breathholds and leading to low scan efficiencies for PET and MR. Here we present a motion-corrected simultaneous DCE-MRI/PET approach which enables imaging with 100% scan efficiency using all data, to improve PET quantification and accurate alignment between both modalities. The proposed technique was evaluated in three patients with hepatic lesions showing an increased contrast-to-noise-ratio of PET tracer uptake by more than 80%. |
| 4336 | Computer 136
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Performance analysis and optimization of MR-based attenuation correction in hybrid PET/MR |
1High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 2Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany, 3TU Dortmund, Dortmund, Germany |
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The recent approach of MR-based attenuation correction in hybrid PET/MR, using a Dixon-VIBE based 4-component µ-map along with an atlas-based bone model, was analysed regarding its accuracy and potentials to reduce deviations from the ground truth. Various CT-based µ-maps were synthesized and the influence of each component on the standardized uptake values was determined for 16 patients. Furthermore, the generated µ-maps were quantitatively compared to the original PET/MR-based µ-maps. It was demonstrated that an adjustment of the lung values and introduction of a second tissue compartment increases the accuracy of the calculated standardized uptake values, particularly for heart and abdomen. |
| 4337 | Computer 137
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GAN based continuous pseudo-CT computation for PET/MR attenuation correction and MR-guided radiation therapy planning |
1GE Global Research, Bangalore, India, 2UCSF, San Fransisco, CA, United States, 3GE Healthcare, Munich, Germany |
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Generation of pseudo CTs from MR images is of interest for applications such as PET/MR attenuation-correction (AC) and MR-guided radiation therapy planning (MRgRTP). In this work, demonstrate a DL method that harnesses the style transfer capability of GAN to compute qualitatively and quantitatively accurate continuous density bone pCT images from Dixon based LAVA-Flex MRI sequence which has a short acquisition time. The method is evaluated for PET/MR attenuation correction. |
| 4338 | Computer 138
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Metabolic Modulation for Enhanced Therapeutic Response |
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, United States, 3Cancer Biosciences, Cancer Research UK Cambridge Institute, AstraZeneca, Cambridge, United Kingdom, 4Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, United States, 5Medicine, University of Pennsylvania, Philadelphia, PA, United States |
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SYNOPSIS: Metastatic prostate cancer is treated with androgen deprivation therapy (ADT), which involves the maximal suppression of circulating testosterone. Although initial responses are generally favorable, most cases progress to metastatic castration resistant prostate cancer (mCRPC), which is refractory to standard ADT. Our goal is to develop a treatment strategy to improve response of mCRPC by combining a clinically utilized metabolic modulator, AZD3965, with docetaxel. AZD3965 effects were measured in vivo by 31P and 1H MRS in PC3 prostate cancer xenografts. In vitro results suggest that AZD3965 enhances the growth inhibitory effect of docetaxel similarly both in PC3 and LNCaP cells although PC3 expresses both MCT1 & 4 and LNCaP only expresses MCT1. |
| 4339 | Computer 139
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CEST pH Imaging as a Diagnostic for Chronic Kidney Disease in Methylmalonic Acidemia (MMA) |
1The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Medical Genomics and Metabolic Genetics Branch, National Institutes of Health (NIH), Bethesda, MD, United States, 3F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 4McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Chronic Kidney Disease (CKD) is a serious complication of methylmalonic acidemia (MMA), manifests with proximal tubular dysfunction, tubulointerstitial nephritis, and eventually decreased glomerular filtration. Routine diagnostic tests, like serum creatinine, leave much to be desired. In this study, we designed an alternative MRI strategy to measure renal perfusion and create pH maps after administering iopamidol, a pH sensitive contrast agent. We detected robust differences in perfusion fraction and pH maps between severe, mild and no renal disease in MMA mouse model. These results demonstrate that MRI may facilitate early detection of kidney disease. |
| 4340 | Computer 140
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A Static Susceptibility Model for MR Images Enhanced by Targeted Magnetic Nanoparticles to Accurately Measure Glomerular Volume in Rat Kidneys |
1Physics, University of Hawaii at Manoa, HONOLULU, HI, United States, 2Radiology, Washington University in St. Louis, St. Louis, MO, United States |
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It is believed that under nephron loss, remaining nephrons compensate by undergoing hypertrophy to maintain a constant filtration surface area and thus maintain homeostasis in GFR. Yet, there are no tools in the clinical setting to measure nephron endowment or glomerular size distribution. Here we used CFE-MRI, a good indicator of nephron number, and a classical model of static susceptibility to accurately measure glomerulus size in the kidneys of rats. |
| 4341 | Computer 141
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Ultrasmall iron oxide particle-enhanced MR imaging of fibrogenesis and fibrolysis of liver fibrosis in mice |
1Laboratory of Imaging Biomarkers, UMR 1149 INSERM-University Paris Diderot, Sorbonne Paris cité, Department of Radiology, Beaujon University Hospital Paris Nord, Clichy, France, 2Unité de technologies Chimiques et biologiques pour la santé (UTCBS), ENSCP Chimie-Paristech, UMR 8258, U1022, University Paris Descartes, Paris, France |
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The aim of our study was to assess if hepatic fibrogenesis and fibrolysis could by differentiated with USPIO-enhanced MR imaging in mice, based on differential uptake of fluorescent USPIO by macrophages. The change in R2* were significantly higher in the fibrogenesis group compared to the healthy group and the regression group 24 hours after the injection of USPIO. Higher USPIO uptake was observed with fluorescence microscopy during fibrogenesis relative to uptake in fibrolysis and healthy livers. Significant correlation was found between R2* and fluorescence intensity. These results suggest that the dynamics of fibrogenesis can be assessed with USPIO enhanced MR imaging. |
| 4342 | Computer 142
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Imaging response to Elafibranor treatment in a rat model of non-alcoholic steatohepatitis non-invasively by oxidized-collagen molecular MRI |
1Athinoula A. Martinos Center for Biomedical Imaging, MGH, Harvard Medical School, Charlestown, MA, United States, 2Division of Surgical Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 3Institute for Innovation in Imaging (i3), Charlestown, MA, United States |
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Elafibranor is a dual agonist of the peroxisome proliferator-activated receptor-⍺ and δ (PPAR-⍺ and δ) in Phase III clinical trials for treatment of non-alcoholic steatohepatitis (NASH). Here, we evaluated the drug’s effectiveness in a choline-deficient high fat diet (CDAHFD) NASH model by imaging oxidized collagen as a marker for fibrogenesis in the liver using a Gd-based probe and MRI. Oxidized collagen MRI of the liver showed that Elafibranor successfully reduced fibrogenesis in rats with histologically-confirmed NASH, ex-vivo total collagen quantification by hydroxyproline assay, and histology staining, also confirmed the anti-fibrotic effect of Elafibranor in the CDAHFD-induced NASH model. |
| 4343 | Computer 143
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Evaluation of Location-Dependent Attenuation of Experimental Autoimmune Encephalomyelitis after Glial-Restricted Progenitor Transplantation using CEST MRI and MRS |
1Johns Hopkins University, Baltimore, MD, United States, 2Kennedy Krieger Institute, Baltimore, MD, United States |
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The utility of CEST MRI and MRS as a noninvasive strategy for visualizing and tracking glial-restricted progenitor cells (GRPs) after transplantation was evaluated. GRPs increased signal in on-resonance variable delay multiple pulse (onVDMP) chemical exchange saturation transfer (CEST) MRI maps and 1H MRS at the lactate peak in cell phantoms, in naïve mice, and in an experimental autoimmune encephalomyelitis mouse model of multiple sclerosis at and/or proximal to the initial location of cells. |
| 4344 | Computer 144
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Approaching the suppression of arm truncation artifact on 18F-FDG-PET/MR attenuation correction map: a feasibility study on MR image synthesis from cycle-GAN |
1Zhongshan Hospital, Shanghai, China, 2United-Imaging, Shanghai, China |
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Arm truncation artifact in PET/MR system was introduced by 1) smaller MR FOV to cover subject’s arm and 2) distorted gradient encoding at the boundary of FOV. PET imaging normally has larger FOV and non-distorted property. In this study, a cycle-GAN model trained with paired inputs of A (PET + pseudo-truncated-MR images) and B (pseudo-none-truncated-MR images) was proposed to synthesize none-truncated-MR images from PET and real-truncated-MR images then used for the generation of attenuation correction map. PET/MR whole body images from 10 patients were used for this feasibility evaluation. The cycle-GAN model was able to synthesize none-truncated-MR images for patients either with partial-arm covered or with distortion artifact in arm region. |
| 4345 | Computer 145
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Neurovascular, muscle, and skin changes on [18F]FDG PET/MRI in foot complex regional pain syndrome (CRPS) |
1Radiology, Stanford University, Stanford, CA, United States, 2Anesthesiology, Stanford University, Stanford, CA, United States, 3Orthopaedics, Stanford University, Stanford, CA, United States |
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Complex regional pain syndrome (CRPS) is a devastating chronic pain condition affecting 50,000 new patients every year in the U.S. Unfortunately, conventional methods for examining musculoskeletal damage such as physical exam or electrodiagnostic methods are very difficult to use for CRPS patients due to their extreme sensitivity to pain. In this abstract, we demonstrate the feasibility of [18F]FDG PET/MRI for investigating musculoskeletal changes from CRPS. Our results show the improved sensitivity of [18F]FDG PET to muscular, neurovascular, and skin changes over MRI, suggesting that [18F]FDG PET/MRI can be a valuable tool to monitor the pathologic process of CRPS. |
| 4346 | Computer 146
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Diagnostic Performance of Amide Proton Transfer-Weighted MRI for Predicting Histological Grade of Hepatocellular Carcinoma |
1Beijing Hospital, Beijing, China, 2Johns Hopkins University, Baltimore, MD, United States |
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Amide proton transfer-weighted (APTw) MR imaging has attracted increasing attention in the field of molecular imaging as a novel contrast mechanism in MRI. The purpose of the study was to prospectively evaluate the potential role of APTw-MRI and morphologic features in predicting the histological grade of hepatocellular carcinoma (HCC). We enrolled 32 HCC patients who underwent routine liver sequences and APTw sequence on a 3.0-T MRI scanner. Our results showed higher APTw values and larger tumor size are potential predictive biomarkers for high-grade HCC. |
| 4347 | Computer 147
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To evaluate the role of APT-w contrast, optimized for normalization and ROIs selection, in differentiating Infective and Neo-plastic Mass Lesions |
1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Center for Magnetic Resonance & Optical Imaging, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Radiology, Fortis Memorial Research Institute, Gurgaon, Haryana, India, 4Department of Biomedical Engineering, All India Institute of Medical Science, New Delhi, India |
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Differentiation of intra-cranial-mass-lesions ( |
| 4348 | Computer 148
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Measuring J-coupling Mediated CEST for Desmosine, a critical amino acid for lung physiology and pathology |
1MGH/Harvard Medical School, Charlestown, MA, United States, 2Radiology and Pathlogy, MGH/Harvard Medical School, Charlestown, MA, United States |
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Chemical Exchange Saturation Transfer (CEST) imaging provides the opportunity for probing important metabolic pathways in vivo. However, clinical implementation of the CEST method for metabolic imaging requires overcoming several technical obstacles. To advance the clinical application of this technology, we propose to generate the CEST effects of labile protons that are polarized via J-couplings by neighboring aliphatic protons while the latter undergo radio frequency irradiation. We tested and proved this concept using desmosine, a unique, pyridinium-containing amino acid that is critical for lung physiology and pathology. Additional work will be concentrated on further systematic investigations and in vivo implementations. |
| 4349 | Computer 149
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A navigator-guided novel motion correction method in simultaneous PET/MR abdominal imaging |
1Department of Nuclear Medicine, Zhongshan Hospital, Shanghai, China, 2United Imaging Healthcare, Shanghai, China, 3UIH America, Houston, TX, United States |
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Simultaneous PET/MR abdominal imaging suffers from respiratory artifacts which causes motion blur of the PET images, further affecting clinical diagnosis. To eliminate motion blur, the work presents a novel PET image motion correction method by optimizing attenuation maps with navigators. The method significantly improves the image quality as well as the work flow and demonstrates its clinical value in detecting lesion in the liver. |
| 4350 | Computer 150
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In vivo monitoring of Mesenchymal Stem Cells in a rat knee with Tissue Saturation SWIFT |
1CHOP, Philadelphia, PA, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States, 3UC Davis, Sacramento, CA, United States |
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Mesenchymal Stem Cells (MSCs) have potentials to be used for the treatment of bone diseases. We developed a new MRI method for detection of Fe-labeled MSCs. This protocol utilizes a resonance frequency shift induced by iron-oxide particles and allows imaging of grafted MSCs with a saturated signal from the host tissue. We compared retention of control and MSCs tagged with a high affinity to the bone tissue peptide. As compared with control, more tagged MSCs were detected at the injection area nine days after implantation. The new protocol allows |
| 4351 | Computer 151
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MR Visualization of Macrophages’ Damage in Response to X-Irradiation by Detecting Intracellular SPIO Deposition |
1Division of Functional Imaging, National Cancer Center, Kashiwa, Japan, 2Division of Radiation Oncology and Particle Therapy, National Cancer Center, Kashiwa, Japan |
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The MR visualization of radiation treatment margins may be helpful during radiotherapy for liver cancer to monitor early response of the tumor and acute damage in non-tumor liver parenchyma. To demonstrate that MR signals from SPIO-labelled Kupffer cells may be changed in direct relation to the cellular response to x-irradiation, we examined the changes in transverse relaxation rates, R2’ (R2’=R2*-R2) of cell phantoms containing SPIO-labelled and x-irradiated macrophage-like J774A.1 cells in vitro. We found that x-irradiation to macrophages can cause SPIO deposition and R2’ elevation in a dose range of 0 to 10 Gy. |
| 4352 | Computer 152
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Tracking nanoparticle mediated colorectal cancer liver metastasis ablation therapy using R2* magnetic resonance imaging |
1Medical College of Wisconsin, Milwaukee, WI, United States |
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We developed sub-100nm optical/MR/X-ray contrast-bearing theranostic nanoparticles (TNPs) based on Gold nanorod cores and Gd3+ oxide shells for interventional image-guided photothermal therapy (PTT). In this study, we explore the value of MRI for tracking TNP-mediated PTT response and distinguishing tumors from normal surrounding tissues in preclinical colorectal liver metastases (CLRM). The results showed that tumors with TNPs depict higher R2*-relaxivity compared to normal liver post-TNP mediated PTT, and this increase persists ten days post-therapy. Therefore, MRI contrast can be used for specifically targeting CRLM tumors, which enables delivering sufficient amount of light to the tumor and tracking the therapy response. |
| 4353 | Computer 153
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Statistical Assessment of Nitroxide Radicals by T1-weighted Dynamic MRI in ex-vivo Porcine Aortic wall |
1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Germany, Wuerzburg, Germany, 2Chair of Tissue Engineering and Regenerative Medicine (TERM), University Hospital Wuerzburg, Germany, Chair of Tissue Engineering and Regenerative Medicine (TERM), University Hospital Wuerzburg, Germany, Wuerzburg, Germany, 3Translational Center ‘Regenerative Therapies’ (TLC-RT), Fraunhofer Institute for Silicate Research, Wuerzburg, Germany (ISC), Wuerzburg, Germany |
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Atherosclerosis genesis is attributed to a breakdown of homeostatic mechanisms undergoing increased oxidative stress followed by inflammation with extension to all aortic layers. Nitroxide radicals (NR) have been used as a redox-sensitive T1 contrast agent in NMR studies. Previous results have demonstrated assessment of exogenous induce redox state by using NR. In this study, we statistically assess the kinetics of NR-induced T1-weighted contrast in the ex-vivo porcine vascular wall. The results demonstrate persistence of the key values of NR induced T1-contrast kinetics and allow stepping further to quantitative assessment of the redox state within the vascular wall. |
| 4354 | Computer 154
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Calibrated fMRI as a Complementary Diagnostic Method for Epilepsy |
1iHuman Institute, ShanghaiTech University, Shanghai, China, 2School of Life Science and Technology, ShanghaiTech University, Shanghai, China, 3Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 4Department of Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 5MR Collaboration, Siemens Healthcare Ltd., Shanghai, China, 6Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China |
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Epilepsy, one of the most common neurological disorders, is a chronic and recurrent disorder of the brain characterized by unprovoked seizures. Unfortunately, conventional diagnostic methods are limited due to the difficulties of precise localization of the epileptogentic zone. Here, we introduce the calibrated functional MRI (fMRI) to calculate the oxygen to glucose index (OGI) with a combined PET/MR system. With this approach we were able to observe large decreases in relative OGI within the affected hemisphere of epileptic patients. Our method, if proven to locate epileptic foci better than glucose-PET methods alone, will represent an important new diagnostic tool for epilepsy. |
| 4355 | Computer 155
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Potential strategies to test the sensitivity of iron oxide nanoparticles as a spin-lattice MR relaxation contrast agent in vivo. |
1Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, Bethesda, MD, United States, 2Laboratory of Functional and Molecular Imaging, National Institute of Health, Bethesda, MD, United States, 3Neurology, Uniformed Services University of the Health Science, Bethesda, MD, United States |
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A well designed MR T1 relaxation contrast agent would provide readily detectible MR image contrast without extensive post-processing and superior spatial resolution compared to other MRI derived biomarkers. However, developing effective an T1 contrast agent would require comprehensive in vivo preclinical study. Thus, it would be highly beneficial to have methodology which can provide quantitative assessment on the relaxation effects of the employed contrast agent on living tissue without damaging the tissue integrity. Here we present a potential strategy to test MR sensitivity on T1 contrast agent on living tissue. The digital simulation provided quantitative assessment on T1 relaxation effect. |
| 4356 | Computer 156
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Qualitative and quantitative morphology/metabolism analysis of infantile spasms using PET/MR and efficacy evaluation of ACTH therapy |
1Nuclear medicine, the general hospital of people liberation army, PLA hospital, Beijing, China, 2Pediatrics, the general hospital of people liberation army, PLA hospital, Beijing, China, 3MR Scientific Marketing，Diagnostic Imaging，Siemens Healthcare. Beijing, P.R. China, Beijing, China, 4MR Collaboration，Diagnostic Imaging，Siemens Healthcare. Shanghai, P.R. China, Shanghai, China |
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This study aimed to investigate the diagnostic performance of positron emission tomography/magnetic resonance imaging (PET/MR) for structural/metabolic abnormality in infantile spasms. We evaluated both the morphology and parameters of PET/MR images by qualitative and quantitative assessment. Our results showed quantitative analysis of PET/MR images could improve the diagnosis of etiologic abnormality. Furthermore, the classification of etiology using PET/MR can indicate the efficacy of adrenocorticotropic hormone (ACTH) treatment and provide valuable information for surgery plan. |
| 4357 | Computer 157
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Investigation of halo-artifacts using improved scatter correction in 68-Ga-PSMA PET/MRI of the prostate |
1Highfield and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, 3Siemens MR, Siemens Healthcare GmbH, Erlangen, Germany, 4Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany |
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A potential challenge of using radiotracer 68-Ga-PSMA for detection and staging of prostate cancer in PET/MR is a frequently observed halo-artifact around the urinary bladder caused by improper scatter correction (SC). Tumor manifestations in these regions might be non-detectable or show distorted SUVs. To evaluate the impact of SC on 68-Ga-PSMA PET/MR imaging, PET data sets of 100 patients were reconstructed twice using standard and improved SC. The improved SC significantly reduces the halo-artifact around the bladder. Measured SUVs in the halo margin on average increased by 325 %, and therefore, considerably affect quantitative assessment of prostate cancer in PET/MR. |
| 4358 | Computer 158
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Characterization of preclinical PET insert for 7T: beyond NEMA testing. |
1KU Leuven, Leuven, Belgium, 2Nuclear Molecular Imaging, Bruker BioSpin Preclinical Imaging Division, Bruker Biospin, Ettlingen, Germany, 3Nuclear Molecular Imaging, Bruker BioSpin Preclinical Imaging Division, Bruker BioSpin, Ettlingen, Germany, 4Biomedical MRI group, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium, 5Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium, 6Instituto de Instrumentación para Imagen Molecular (I3M), Universitat Politècnica de València, Valencia, Spain |
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While we already reported indexes of the performance of one of the first commercially available SiPM-based MR-compatible PET Insert, no NEMA testing has been reported until now. Moreover the NEMA protocol for evaluating the performance of preclinical PET scanner, do not cover the integration and potential interference between PET and MRI. We hereby propose and report an extended NEMA protocol demonstrating the performance of the MRI (Biospec USR 70/30) with and without the presence of the PET Insert as well as the performance of the PET with simultaneous MRI acquisition. |
| 4359 | Computer 159
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Simultaneous PET/MRI to detect brain tumour metabolic and functional heterogeneity |
1Department of Information Engineering, University of Padova, Padova, Italy, 2Padova Neuroscience Center, University of Padova, Padova, Italy, 3Department of Neuroscience, University of Padova, Padova, Italy, 4Department of Molecular Imaging, University of Padova, Padova, Italy |
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Demarcation for brain tumour neurosurgical resection is typically performed using Fluid Attenuated Inversion Recovery images hyperintensities. In this study, we investigated in glioma patients whether these hyperintensities represent structural alterations that are metabolically and functionally homogeneous using simultaneous measurements of quantitative 18-Fluoro-deoxyglucose PET and resting state functional magnetic resonance imaging. FLAIR hyperintense regions resulted to be heterogeneous both at metabolic and functional standpoint and only partially significantly altered when compared with contralateral homologous white matter. These results support the hypothesis that multi-parametric approaches might improve the outcome of brain surgery informing the resection procedure. |
| 4360 | Computer 160
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Functional signaling contributions of D1 and D2 dopamine receptors during VTA stimulation in non-human primates |
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Laboratory of Neuro- and Psychophysiology, Medical School, KU Leuven, KU Leuven, Leuven, Belgium, 4Division of Health Sciences and Technology, Harvard-MIT, Cambridge, MA, United States |
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Deep brain stimulation in the ventral tegmental area (VTA) has shown promise in modulating reward and learning. However, its underlying molecular mechanisms are still largely unexplored. In this study, fMRI and PET together with selective pharmacological blocking was used to distinguish dopamine receptor subtype-specific mechanisms of VTA stimulation in a non-human primate model with a chronically implanted stimulation electrode. Our results show that the main dopaminergic contribution to fMRI signal is likely driven by D1 receptor signaling, with a smaller D2 receptor contribution. Overall, this is a novel finding distinguishing dopaminergic receptor subtypes involved in VTA stimulation. |
| 4361 | Computer 161
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Optimization of saturation frequency offset step size for CEST asymmetry contrast of human brain at 7T MRI |
1Center for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Center for Magnetic Resonance & Optical Imaging, University of Pennsylvania, Philadelphia, PA, United States, 3All India Institute of Medical Science, New Delhi, India |
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Chemical-exchange-saturation-transfer(CEST) MRI is being used for mapping molecular-information. CEST contrasts such as Creatine-weighted(frequency-offset=2ppm), Glutamate-weighted(frequency-offset=2ppm) and APT-weighted(frequency-offset=3.5ppm) are being explored for potential clinical applications. Computation of contrast(CEST-asymmetry) at a frequency-offset require data acquisition at multiple offset-frequencies either for B0-inhomogenity correction or generating z-spectra. Objective of this study was to evaluate the effect of sampling frequency-offset step-size (0.1, 0.2, 0.3, 0.4, 0.5ppm) on CEST-asymmetry contrast. Standard-deviation, coefficient-of-variation and normalized-mean-sum-squared-errors(nMSSE) increases while correlation decreases with increase in step-size. By considering both scan time and error, step-size of 0.2 to 0.3 is optimum for computing CESTasym. |
| 4362 | Computer 162
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Using iron oxides and perfluorocarbons with magnetic resonance imaging for simultaneous cell tracking of two populations in a model of stem cell rejection |
1Robarts Research Institute, London, ON, Canada, 2Medical Biophysics, The University of Western Ontario, London, ON, Canada |
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Mesenchymal stem cells (MSCs) are a promising cellular therapeutic. However, this therapy is limited by MSC apoptosis following administration, which can ultimately trigger immune rejection. In this study we explored the ability to label, detect, and quantify both MSCs and infiltrating macrophages using both iron and fluorine-19 (19F) based MRI cell tracking. With a dual-tuned surface coil and a 3D bSSFP sequence, we demonstrated that both cell populations can be monitored during the same imaging session. This is the first study to image macrophage infiltration in vivo using 19F on a 3T clinical MRI system. |
| 4363 | Computer 163
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Evaluation of attenuation reduction of a dedicated carotid PET/MRI coil |
1Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, 2CARIM School for Cardiovascular Diseases, Maastricht, Netherlands, 3Machnet B.V, Roden, Netherlands |
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Dedicated RF coils are required to acquire high resolution MR images. These RF coils are in the PET field of view in a PET/MRI scanner. Therefore, attenuation from these coils can cause bias in PET quantification. This study compares a newly developed dedicated PET/MRI RF coil with a coil designed for MRI-only. Both a phantom and patients injected with 18F-FDG were scanned with both coils and without a dedicated coil (baseline). Activity measured in the phantom was significantly reduced with the MRI-only coil compared to the new coil, which did not show any significant attenuation effect. Results in patients support this finding. |
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Low Dose PET/MR Imaging in Crohn's Disease |
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI, United States, 3Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States |
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For patients with Crohn’s Disease, reduction of radiation exposure during imaging exams is critical as life-long surveillance is often required. This research aims to reconstruct full dose PET images from low dose and MR images using a deep learning approach. Based on the analysis in twenty patients utilizing Leave-One-Out-Cross-Validation, a 10x reduction from clinical FDG tracer dose is attainable. |
| 4365 | Computer 165
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Innate immune cell tracking in the glioma microenvironment by correlated magnetic resonance imaging and multi photon microscopy (MR-MPM) |
1Neuroradiology, Neuroradiology Department, University Hospital Heidelberg, Heidelberg, Germany, 2Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DKTK) within the German Cancer Research Center (DKFZ), Heidelberg, Germany, 3Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany, 5Department of Neurology, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany |
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The tumor microenvironment (TME) plays a key role for tumor biology. Composition of the TME correlates with overall survival and governs therapy response. Non invasive assessment of the TME has been notoriously difficult. We have designed an imaging strategy to non invasively visualize innate immune cell dynamics in the TME by correlated MRI and multiphoton microscopy. This approach allowed us to visualize the single steps of nanoparticle uptake by blood born monocytes that give rise to tumor macrophages in an experimental glioma model. We further found that nanoparticle uptake also occurs via the disrupted blood-brain barrier into the brain parenchyma where NP are taken up by tumor associated microglia. |
| 4366 | Computer 166
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Specific quantification of 57Fe-nanoparticles by combined MRI and Mass Spectrometric Imaging |
1Institute of Clinical Radiology, University of Muenster, Muenster, Germany, 2Institute for Inorganic and Analytical Chemistry, University of Muenster, Muenster, Germany |
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Iron oxide nanoparticles (ION) provide high sensitivity for MRI cell tracking, but signal reductions cannot easily be separated from those originating from endogenous iron. We combine 57Fe-ION MRI with laser ablation-inductively coupled plasma-mass spectrometry for differentiation between endogenous iron (56Fe) and applied ION. We establish 57Fe-ION as contrast agent and assess their long-term fate. The technique facilitates specific and quantifiable cell tracking. ION were first internalized by phagocyting cells predominantly in liver and spleen, but in the long-term relocated to endogenous iron sources as the blood or red pulp of the spleen and, interestingly, also in the brain parenchyma. |
| 4367 | Computer 167
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In vivo detection and quantification of plaque rupture using a novel fibrin-binding PET tracer |
1Athinoula A. Martinos Center for Biomedical Imaging, MGH / Harvard Medical School, Charlestown, MA, United States, 2Department of Medicine, Massachusetts General Hospital, Boston, MA, United States, 3Gordon Center for Medical Imaging, Massachusetts General Hospital, Boston, MA, United States |
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Detecting high-risk atherosclerotic plaques prone to rupture is still one of the main challenges in cardiovascular imaging that could help save many lives. This study presents a novel fibrin-binding positron emission tomography (PET) radiotracer, 68Ga-CM246, which allows accurate detection and quantification of plaque rupture in an animal model of atherosclerosis using simultaneous PET/MRI. Our in vivo PET results show that 68Ga-CM246 is highly sensitive and very specific to fibrin clots in ruptured plaques. Our results confirm the potential of the 68Ga-CM246 to translate into the clinic to identify in humans those plaques at risk of rupture showing intraplaque hemorrhage. |
| 4368 | Computer 168
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Redox Active Iron Complexes as Biochemically Responsive MRI Contrast Agents. |
1Radiology/ Martinos Center, Massachusetts General Hospital, Charlestown, MA, United States |
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The redox active chelate Fe-PyC3A provides an order of magnitude change in relaxivity by switching between the weakly and strongly contrasting Fe(2+) and Fe(3+) oxidation states, respectively. This activatable relaxivity change is field independent between 1.4T and 11.7T, and far exceeds what is possible with Gd contrast agents. Oxidation state interchange is triggered by biochemical reductants and oxidants such cysteine and hydrogen peroxide. Redox active iron complexes offer a new paradigm for the design of biochemically responsive MRI contrast agents. |
| 4369 | Computer 169
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Fluorine-19 (19F) Labeled Benzothiazole Derivative as a Biosensor for detection of Alzheimer’s Disease using Magnetic Resonance Imaging |
1Chemistry and Materials Science Program, Lakehead University, Thunder Bay, ON, Canada, 2Chemistry, Lakehead University, Thunder Bay, ON, Canada, 3Thunder Bay Regional Health Research Institute, Thunder Bay, ON, Canada, 4Enamine Ltd, Kyiv, Ukraine, 5Northern Ontario School of Medicine, Thunder Bay, ON, Canada |
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There are 5-7 million new cases of Alzheimer’s disease (AD) recorded each year worldwide. Typically, Positron Emission Tomography (PET) is used for the detection of amyloid b plaques allow for diagnosis of |
| 4370 | Computer 170
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Temperature Sensitive 19F-Substituted Molecules for Combined Proton-/Fluorine-Imaging in a 7 T Whole-Body MRI System |
1Institute for Biometrics and Medical Informatics, Otto-von-Guericke University, Magdeburg, Germany, 2Department of Biomicrosystem Technology and Korea Artificial Organ Center, Korea University, Seoul, Korea, Republic of |
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19F MR spectroscopy and imaging represent important tools for the development of new MR contrast agents and pharmaceutics. Until now, there are only a few published data that described the influence of temperature changes to the 19F chemical shifts in aqueous solutions. Temperature coefficients up to ~ 8.7Hz/K were determined. Thermoresponsive agents are of high interest in, e.g. hyperthermia studies. Changes in signal intensity and chemical shift give information of the local temperature. Here, we present novel MR spectroscopic and imaging data, which describe the 19F MR signal temperature dependency of different fluorinated organic substrates in isotonic saline solution and their temperature calculation methods. |
| 4371 | Computer 171
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Overcoming short T2 issue with the use of 3D UTE for imaging of 19F-loaded theranostic nanocapsules |
1Department of Magnetic Resonance Imaging, Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland, 2Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland |
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The development of heteronuclear magnetic resonance imaging is one of the strategies in a control of a biodistribution of therapeutic agents. Molecules containing 19F atoms are particularly attractive for use as MRI markers due to favorable physical properties of fluorine nucleus. Advances in MRI instrumentation and ultrafast pulse sequence development expanded the range of fluorine compounds available as new MRI markers. Optimization of imaging parameters of such sequences enables the visualization of 19F compounds with the less preferable characteristic. In this paper, we report the application of the 3D UTE sequence at a high field for imaging of compounds with a complex 19FNMR spectrum and very short T2.
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Metabolic differences between hyperpolarized 13C pyruvate MRI and 18F-FDG PET imaging in a rat model of spontaneous brain cancer |
1Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Neurology, Stanford University, Stanford, CA, United States |
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Hyperpolarized [1-13C]pyruvate MRI and 18F-FDG PET imaging signals were compared in a rat model of spontaneous slow growing glioma, which mimics the growth pattern of some human gliomas. No enhancement of 18F-FDG was observed in the tumor regions relative to normal appearing brain. Hyperpolarized 13C MRI however did show metabolic differences in all animals. The present study suggests that hyperpolarized 13C MRS potentially may be used to identify and characterize gliomas, which are 18F-FDG negative. |
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Dynamic Imaging of Vitamin C Pharmacokinetics by 13C Chemical Shift Imaging without Hyperpolarization |
1National Cancer Institute, Bethesda, MD, United States |
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Intravenously injected vitamin C is re-emerging as a potential chemotherapeutic agent but questions remain about its bioavailability and metabolic fate. Using newly developed methods for signal denoising, we show that is possible to image vitamin C pharmacokinetics by non-hyperpolarized 13C MRI with significant sensitivity and time resolution that the accumulation of vitamin C into a tumor and its metabolism into downstream metabolites can be visualized. Since the method does not rely on hyperpolarization and therefore does not have restrictions on T1 relaxation, it can be potentially extended to other highly tolerated drugs. |
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Liver Fatty Acid Profile Mapping with Accelerated Free-Breathing Spectroscopic Imaging |
1Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada, 2Biomedical Translational Imaging Centre (BIOTIC), Halifax, NS, Canada, 3Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada, 4Biomedical Engineering, Dalhousie University, Halifax, NS, Canada |
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Fat composition in the liver, particularly the amount of polyunsaturated fat, may be important in characterizing NAFLD. Spatially resolved maps of unsaturation indices were generated using an accelerated free-breathing spin echo single point imaging technique. Multiple under-sampling patterns were acquired sequentially to ensure oversampling of the k-space centre even after retrospective motion correction. The technique was validated using a set of oil/water mixture phantoms and evaluated in an in vivo mouse study (N=8). |
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Real-time Metabolic Investigations of Living Cells by NMR – First Experiences |
1Departments DOLS, University Hospital of Bern, Switzerland, Institute of Clinical Chemistry, University Hospital Bern, Switzerland, Bern, Switzerland, 2Departments of Clinical Research and Radiology, University of Bern, Switzerland, Magnetic Resonance Spectroscopy and Methodology - Department of Clinical Research - University Bern/Switzerland, Bern, Switzerland, 3Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland, Bern, Switzerland, 4Department of Pediatric Endocrinology, Diabetology and Metabolism, University Children’s Hospital of Bern, Switzerland, Bern, Switzerland |
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NMR approaches using flow systems for real-time spectroscopy of living cells were explored as early as the 80s but did not become routine due to different technical obstacles. We show the technical feasibility of real-time metabolic monitoring in 3D culture inside our established NMR bioreactor using the commercially available InsightCellTM (Bruker) tool, which supposedly eases bioreactor setup. Human skin fibroblasts showed reproducible glucose and O2 measurements in stop-and-go experiments over 12 hours. Chemical interventions on aerobic energy production pathways showed fast response by increasing rate of anaerobic glycolysis, which could be reversed by subsequent inhibition of glycolytic pathway. |