Weekend and Oral

Electronic Posters

Traditional Poster

Breast Cancer: Clinical

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1029.   Breast PET/MRI Correlations Between SUVmax, ADCmin, Tumor Markers and Systemic Disease

                                Amy Melsaether1, Akshat C. Pujara2, Eric Sigmund2, Alana Amarosa2, Freya Schnabel2, Deirdre Kiely2, Sungheon Kim2, Linda Moy2

                                1NYU, New York, United States; 2NYU, NY, United States

 

In this preliminary study, we address whether the PET and DWI data (SUV max and ADC min) acquired during a breast PET/MRI correlate with each other and with breast cancer tumor markers and with systemic disease.

 

 

                    1030.   Assessment of High Spatial Resolution 3D T2W Fat Nulled Images: A Comparison with 2D T2W Fat Sat Images

                                Martin D. Pickles1, Daniel Litwiller2, Lindsay W. Turnbull1

                                1Centre for Magnetic Resonance Investigations, HYMS at University of Hull, Hull, East Yorkshire, United Kingdom; 2Global MR Applications and Workflow, GE Healthcare, Rochester, MN, United States

 

Further improvements in the specificity of MR breast are required. Recently, a 3D FSE T2W modified 3-point DIXON technique (CUBE-IDEAL) became available. The purpose of this work is to evaluate CUBE-IDEAL and compare against traditional 2D T2W FSE fat saturated images. Sixty-nine patients were imaged on a 3.0T scanner. The results of this assessment suggest a similar level of performance overall. However, a number of key points should be underscored. Firstly, CUBE-IDEAL did outperform FSE at fat nulling. Secondly, CUBE-IDEAL can be reformatted into any plane. Thirdly, CUBE-IDEAL presents a time saving over the traditional FSE sequence.

                    1031.   DWI of Breast at 3T: Effects of Fibroglandular Tissue Composition and Background Parenchymal Enhancement in Patients with Malignant and Benign Lesions

                                Soledad Milans1, Sujata Patil2, Elizabeth Morris2, Sunitha Thakur1

                                1Memorial Sloan-Kettering Cancer Center, New York, NY, United States; 2Memorial Sloan-Kettering Cancer Center, NY, United States

 

The amount of fibroglandular tissue (FGT) density and the level of background parenchymal enhancement (BPE) are MRI features of normal breast. Studies showed increased BPE to be strongly predictive of breast cancer odds as with increased FGT. We propose to evaluate the effect of FGT density and BPE on ADC values in patients with malignant and benign findings at 3.0T. FGT-ADC values were significantly higher in patients with malignant lesions with higher density compared to lower density (p=0.0073). In patients with benign lesions, difference is smaller between both groups (p=0.015). No significant difference was observed in FGT-ADC values with BPE.

                    1032.   Diffusion MRI and In-Vivo Proton MR Spectroscopy Study of the Differentiation of Malignant Breast Tissue of Breast Cancer Patients and the Normal Breast Tissue of Healthy Lactating Women Volunteers

                                Naranamangalam R. Jagannathan1, Khushbu Agarwal1, Rani G. Sah1, Uma Sharma1, Rajinder Parshad2, Vurthaluru Seenu2

                                1Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, Delhi, India; 2Department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, Delhi, India

 

Diffusion weighted imaging and in-vivo proton MRS in lactating women volunteers (n=16) and in patients with breast cancer (n=13) showed total choline peak in 16/16 malignant cases and in 11/13 lactating women volunteers. Further, 11/13 of lactating women showed a lactose peak at 3.8 ppm. tCho concentration was similar in both groups while higher ADC was observed in lactating women. Our study demonstrated that higher ADC value together with the presence of a lactose peak may aid in the differentiation of changes that occur in the breast tissues due to normal physiological conditions as compared with malignant transformations.

                    1033.   A Comparison of Short and Standard Exam Time Breast MR Studies

                                Martin D. Pickles1, Lindsay W. Turnbull1, Peter Gibbs1, Martine Dujardin1

                                1Centre for Magnetic Resonance Investigations, HYMS at University of Hull, Hull, East Yorkshire, United Kingdom

 

We believe that a short breast MR examination contains the necessary information to allow an accurate diagnosis. The purpose of this study is to determine the technical feasibility of a short examination and to obtain preliminary comparative data against the standard examination. Nineteen participants were imaged on a 3.0T scanner twice (standard and short). Results suggest that the short breast MR examination is not only feasible but has good agreement with the standard examination. This study has demonstrated that high spatial and temporal resolution data can be acquire in only 12minutes with similar results to much longer MR examinations.

                    1034.   Correlation of Electric Conductivity with Prognostic Factors in Invasive Breast Cancer

                                Soo-Yeon Kim1, Jaewook Shin2, Dong-Hyun Kim2, Min-Jung Kim1, Eun-Kyung Kim1

                                1Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Seodaemun-gu, Korea; 2Electronic and Electronic Engineering, Yonsei University, Seoul, Seodaemun-gu, Korea

 

The electric conductivity has shown its potential to differentiate benign and malignant breast tissue. We investigate the correlation between the electric conductivity with known prognostic factors of invasive breast cancer using the electric properties tomography reconstruction algorithm and multi-receive coil combined technique. Breast cancers with the established poor prognostic factors (axillary lymph node metastasis, lymphovascular invasion and high histologic grade) showed higher conductivity value than those without. Our results show the possibility that the electric conductivity can be differentiated according to the known prognostic markers in invasive breast cancers.

                    1035.   Breast Cancer Assessment Based on Perfusion Dependence in Diffusion Weighted Imaging Using Different Monoexponential Fitting Schemes

                                Jose Ramon Teruel1, 2, Agnes Østlie3, Hans Erikssønn Fjøsne4, 5, Tone Frost Bathen1, Pål Erik Goa, 26

                                1Department of Circulation and Medical Imaging, NTNU, Trondheim, Norway; 2St. Olavs University Hospital, Trondheim, Norway; 3Department of Radiology, St. Olavs University Hospital, Trondheim, Norway; 4Department of Surgery, St. Olavs University Hospital, Trondheim, Norway; 5Institute of Cancer Research and Molecular Medicine, NTNU, Trondheim, Norway; 6Department of Physics, NTNU, Trondheim, Norway

 

In this study, a simplified approach to obtain perfusion influence from diffusion weighted imaging (DWI) measurements for breast cancer assessment is proposed. Our results present how the relative perfusion effect derived from different monoexponential fitting schemes of DWI measurements can be obtained. Furthermore, this simplified approach offers a potential for breast cancer differentiation by means of the derived biomarker.

                    1036.   Breast Dynamic MR Features Including Texture Analysis Associated with Pathologic Prognostic Factors in Triple Negative Breast Cancers.

                                Bo La Yun1, Sun Mi Kim1, Mijung Jang2, Hye Shin Ahn2, Kyung Eun Cho2, Bohyoung Kim2, Hochul Kang3, Ji Young Kim2

                                1radiology, Seoul national Univ. Bundang Hosp. , Seoungnam-si, Kyongki-do, Korea; 2radiology, Seoul national Univ. Bundang Hosp., Seoungnam-si, Kyongki-do, Korea; 3Seoul national Univ, Seoul, Korea

 

Triple negative breast cancers are heterogeneous disease and poor prognosis. We were investigated early and delayed enhancement pattern and texture feature on breast dynamic MR image. In this study, We found that early and delayed enhancement pattern (rapid and plateu) and texture features (high entropy and low homogniety) in breast dynamic MR were associated with traditional pathologic poor prognosis factors in triple negative breast tumor. These image features could predict preoperative breast cancer aggressiveness.

           

                    1037.   Detection of Altered Adipose Tissue Composition in Breast Cancer Patients Using MR Spectroscopy

                                Palamadai N. Venkatasubramanian1, George Iordanescu1, Matthew M. Smith1, Jennifer L. Gnerlich2, Katherine Yao3, Alice M. Wyrwicz1

                                1Radiology, NorthShore University HealthSystem, Evanston, IL, United States; 2Surgery, The University of Chicago Medical Center, Chicago, IL, United States; 3Surgery, NorthShore University HealthSystem, Evanston, IL, United States

 

Using ex vivo MR spectroscopy we found alterations in the fatty acid composition of peritumoral adipose tissue from breast cancer patients, relative to adipose tissue from a distal location within the same breast.  MR-measured compositions of breast adipose tissues could predict known pathological criteria for invasive breast cancers.  Our results suggest that in vivo MRS may have potential for developing a noninvasive biomarker for invasive breast cancers.

                    1038.   Lipid Deregulation in Women Carrying the BRCA Mutations: Non Invasive Evaluation by Two-Dimensional Spectroscopy

                                Saadallah Ramadan1, Jameen Arm2, Gorane Santamaria3, Judith Silcock4, Jessica Buck5, Michelle Roy6, Kin Men Leong7, Peter Lau7, David Clark4, Peter Malycha6, Carolyn Mountford6

                                1School of Health Sciences, University of Newcastle, Callaghan, NSW, Australia; 2Hunter New England Health, The Mater Hospital, Callaghan, NSW, Australia; 3Department of Radiology, Hospital Clinic de Barcelona, Villarroel, Spain; 4The Breast & Endocrine Centre, NSW, Australia; 5School of Health Sciences, University of Newcastle, NSW, Australia; 6School of Health Sciences, Centre for MR in Health, NSW, Australia; 7Calvary Mater Hospital, NSW, Australia

 

BRCA1 and BRCA2 genes belong to the tumor suppressor family and patients with these genes are at increased risk of developping breast cancer. In this study, we apply in vivo two-dimensional 2D localized correlation spectroscopy (L-COSY) to look for a premalignant state in the breast tissues of apparently healthy women carrying the BRCA gene mutations and others with a family history. We propose the hypothesis that those with the BRCA gene mutations would have altered chemistry reflective of a preinvasive state.

                    1039.    Errors Associated with Followup Measurments of ADC in Assessing Response to Neoadjuvant Chemotherapy

                                Shelley Waugh1, Lukasz Priba1, Sarah Vinnicombe2

                                1Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom; 2Division of Cancer Research, University of Dundee, Dundee, United Kingdom

 

This study considers the use of apparent diffusion coefficient (ADC) measures as an indicator of early response to neoadjuvant chemotherapy.  As ADC changes are utilised in clinical practice, this investigation considers the multiple factors that may influence these measurements and could influence classification of response according to RECIST criteria.  Scanner stability, scan-scan repeatability and intra-observer repeatability are measured with reference to the order of magnitude of ADC changes likely to be encountered in clinical patients who respond, partially respond and have stable disease.

 

                    1040.    Acoustic Radiation Contrast in Magnetic Resonance to Visualize Viscoelastic Properties in Human Breast - Preparation of Clinical Trial

                                Judith Wild1, Anna-Lisa Kofahl1, Deniz Ulucay1, Sebastian Theilenberg1, Carsten Urbach1, Jürgen Finsterbusch2, Kerstin Rhiem3, Peter Trautner4, Karl Maier1

                                1University of Bonn, Bonn, Germany; 2University Medical Center Hamburg, Hamburg, Germany; 3University Medical Center Cologne, Cologne, Germany; 4Life & Brain GmbH, Bonn, Germany

 

The early detection of breast cancer has severely improved during the past 20 years, but there is still room for improvement like a better clarification of indications without using ionizing radiation. The evaluation of biopsy data showed that about 80% of women diagnosed with cancer after the different types of imaging do not have cancer. We target on improving this high percentage by improving the specificity by measuring the elasticity of lesions. Measurements on 10 volunteers with well known lesions provide an important step towards seeing if ARC-MR is capable to improve the specificity of standard breast cancer diagnostic.

                    1041.   Comparison of Steady-State and Spin-Echo DWI Based on Morphological Assessment of Breast Lesions

                                Kristin L. Granlund1, 2, Debra Ikeda1, Jafi Lipson1, Jennifer Kao1, Jung Min Chang3, Brian Hargreaves1, Bruce Daniel1

                                1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States; 3Radiology, Seoul National University Hospital, Seoulq, Korea

 

The DESS sequence has been used to acquire diffusion-weighted images, and this study evaluates DESS images relative to EPI DWI images. Four radiologists were surveyed about the image quality and BI-RADS scores of images containing pathology-proven breast lesions. The DESS sequence acquired sharper diffusion-weighted breast images than EPI (p<0.001). ROC curves were calculated from the BI-RADS scores, and the DESS sequence had a larger AUC (0.74 for DESS, 0.68 for EPI) and a tighter confidence interval. Better image quality facilitates morphological assessment of lesion malignancy.

                    1042.   Comparison of the Value of DWI Based on Monoexponential and Stretched Exponential Model in Differential Diagnosis Between Benign and Malignant Lesions of Breast

                                Jie He1, Yan Zhang1, Jingliang Cheng1, Ying Hu1, Anfei Wang1, Dandan Zheng2, Xiaoyan Wang1

                                1Department of MRI, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, HeNan, China; 2GE healthcare, Beijing, China

 

MRI has been widely used in the diagnosis of breast disease. However, the calculation of apparent diffusion coefficient by simple monoexponential relationship between MRI signal and b value does not fully account for tissue behavior. Intravoxel incoherent motion (IVIM) method allows quantitative parameters that reflect tissue micro capillary perfusion and tissue diffusivity. In this study, the stretched-exponential model was used to generate ¦Á and distributed diffusion coefficient (DDC) maps. The ¦Á values and DDCs were compared with traditional monoexponential ADC in the differential diagnosis of breast benign and malignant lesions.

Traditional Poster

Breast Cancer: Technical

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1043.   Correlation of Percent Breast Density with Background Parenchymal Enhancement Measured in MRI

                                Jeon-Hor Chen1, 2, Yifan Li3, Hon Yu3, Shadfar Bahri3, Rita S. Mehta4, Min-Ying Su3

                                1Center for Functional Onco-Imaging, University of California , Irvine, CA, United States; 2Department of Radiology, Eda Hospital and I-Shou University, Kaohsiung, Taiwan; 3Center for Functional Onco-Imaging, University of California, Irvine, CA, United States; 4Department of Medicine, University of California, Irvine, CA, United States

 

In this study we aimed to correlate percent breast density (PD) and background parenchymal enhancement (BPE) in the contralateral normal breast (CNB) of patients diagnosed with breast cancer. Breast MR images of the CNB of 117 patients were studied. The quantification of the fibroglandular tissue volume (FV) was based on a computer-assisted algorithm. The mean BPE and the hot spot enhancement were correlated with age, and also with FV and PD. Our study showed that BPE, measured by the averaged enhancement of the whole FV or by hot spot, did not correlate well with quantitative measurement of PD and FV.

                    1044.   Impact of Positional Difference on the Measurement of Breast Density in MRI

                                Jeon-Hor Chen1, 2, Siwa Chan3, Yi-Ting Tang4, Angela T. Cheriyan1, Nikita Rakesh Shah1, Min-Ying Su1

                                1Center for Functional Onco-Imaging, University of California , Irvine, CA, United States; 2Department of Radiology, Eda Hospital and I-Shou University, Kaohsiung, Taiwan; 3Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan; 4Department of Medical Imaging, China Medical University, Taichung, Taiwan

 

We conducted a study to investigate the consistency of percent breast density measured in MRI in four different positions and imaging resolution. The breast and fibroglandular tissue segmentation was based on an established novel method. Results of FV and PD measurement show small variations, with an averaged CV of <9%, among the four MR studies. Remarkable measurement variation did occur in some subjects in hands-down position, compared to hands-up position. The results from our MR consistency study indicate that MR imaging data from multi-centers, regardless of patients’ positions (hand-up or hands-down), can be combined for analysis.

 

 

 

                    1045.   Volumetric Breast Density Quantification from 2D Mamographies Compared with Breast MRI

                                Camila Munoz1, Dravna Razmilic2, Maria E. Navarro2, Paula Espinoza2, Cristian Tejos1, Pablo Irarrazaval1, Sergio Uribe1, Marcelo E. Andia, 12

                                1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Region Metropolitana, Chile; 2Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Region Metropolitana, Chile

 

Breast density is a major risk factor of breast cancer, and is usually assessed visually from mammograms. This has two main disadvantages: there is not a standard measure of breast density, as the breast is classsified in qualitative categories, and this assessment does not consider that mammography is a 2D projection of the breast volume. We developed a method to quantify volumetric breast density from mammograms and a semi-automatic method that quantifies this measure in 3D breast MRI. Thus, it is possible to obtain an equivalent quantitative measure of breast density between both imaging techniques, solving the issues mentioned above.

                    1046.   A Novel and Affordable DCE-MRI Phantom: Prospective Assessment of DCE-MRI Breast Protocols

                                Araminta E. W. Ledger1, Marco Borri1, Hector Sanchez Casas1, Craig Cummings1, Maria A. Schmidt1, Martin O. Leach1

                                1CR-UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

 

DCE-MRI is an established component of breast screening protocols, and uses the empirical classification of contrast agent (CA) enhancement curves to aid diagnosis. However, CA enhancement curves resulting from varying parameter selections are difficult to assess prospectively. This abstract uses a novel and affordable DCE-MRI phantom to assess the effect of common sequence alterations (CA injection timing and k-space sampling scheme) on the CA enhancement curves obtained from two clinical DCE-MRI sequences. Both CA injection timing and k-space sampling pattern resulted in measurable curve differences - sequence comparison with this phantom can therefore help to establish robust DCE-MRI breast protocols.

                    1047.   Universal Breast Phantom for Quantitative MRI

                                Kathryn E. Keenan1, Sheye O. Aliu2, Lisa J. Wilmes2, David C. Newitt2, Elizabeth Horneber3, Karl F. Stupic1, Michael A. Boss1, Michael G. Snow4, William Hollander4, Stephen E. Russek1, Nola M. Hylton2

                                1National Institute of Standards and Technology, Boulder, CO, United States; 2University of California San Francisco, San Francisco, CA, United States; 3University of Colorado, Boulder, CO, United States; 4High Precision Devices, Boulder, CO, United States

 

A novel breast phantom was created for the breast imaging community for implementation of quality control measures. The phantom contains well-distributed fat and fibroglandular T1 relaxation mimics and diffusion mimics. In addition, the phantom has a flexible outer shell so that it is compatible with several coil designs. In initial testing, the phantom fit in several coil designs, enabled fat-suppression tests, and allowed assessment of diffusion artifacts. Please visit our website for additional information: http://collaborate.nist.gov/mriphantoms/bin/view/MriPhantoms/BreastPhantom.

                    1048.   A Simulation Study of the Flexible TWIST View Sharing Impact on the Breast DCE MRI

                                Yuan Le1, Marcel Dominik Nickel2, Randall Kroeker2, Christian Geppert2, Brian Dale2, Hal D. Kipfer3, Chen Lin1

                                1Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, IN, United States; 2Siemens Healthcare, NC, United States; 3Radiology and Imaging Science, Indiana University School of Medicine, Indiana, United States

 

The acquisition of breast DCE-MRI using a flexible TWIST view sharing technique was simulated. A digital ‘phantom’ was generated with three 5mm uniform spherical lesions of ‘persistent’, ‘plateau’ and ‘wash-out’ type of contrast uptake, and one 10 mm complex tumor with a mixture of all three types of enhancements. Our results show that with the typical spatial resolution in clinical breast DCE-MRI, TWIST view sharing parameters of pA=20% and pB=20% provides the lowest overall RMS error for all time points, while pA=50% and pB=50% produces image with minimum error at the peak contrast uptake.

                    1049.   Clinical Feasibility of CAIPIRINHA-Dixon-TWIST (CDT)-Volume-Interpolated Breath-Hold Examination (VIBE) for Breast DCE-MRI

                                Wen Hao1, Bin Zhao1, Guangbin Wang1, Hui Liu2, Cuiyan Wang1

                                1Magnetic resonance imaging, Shandong medical imaging research institution, Shandong University, Jinan, ShanDong, China; 2MR Collaboration NEA, Siemens Healthcare, Shanghai, China

 

This abstract is about assessment performed to investigate the clinical feasibility of CDT-VIBE for quantitative breast DCE-MRI. In conclusion, we believe that CDT-VIBE can be used in breast DCE-MRI for detecting and depicting lesions because of its high spatial resolution and nearly equal image quality to conventional VIBE image. Therefore, it is clinically feasible to replace standard 60-90 second conventional GRE sequence by CDT-VIBE sequence for quantitative breast DCE-MRI with the acquisition schemes employed in this study.

                    1050.   Self-Organizing Map Kinetic Features as Prognostic Markers for Classifying Gene Expression Risk for Breast Cancer Recurrence

                                Majid Mahrooghy1, Ahmed B. Ashraf1, Dania Daye1, Carolyn Mies2, Mark Rosen1, Michael Feldman2, Despina Kontos1

                                1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, United States

 

We developed DCE-MRI kinetic heterogeneity features using self-organizing map (SOM) neural networks. We use SOM to cluster tumor pixels based on kinetics and extract features including variance and entropy of cluster size, variance of cluster kinetic features, mean and variance of weighted cluster kinetics, and the kinetic features of the cluster having maximum peak enhancement. We evaluated these features for classifying tumor recurrence risk as determined by a validated gene expression assay, and compared their performance to current standard kinetics. Our features have ROC AUC=0.80 for classifying tumors at low- versus high- risk of recurrence, outperforming standard kinetics with AUC=0.65.

                    1051.   Non-Rigid-Registration of Breast Dynamic Contrast-Enhanced MRI Data: Comparison and Evaluation of B-Splines and Symmetric Diffeomorphic Normalization Based Methods

                                Venkata Veerendranadh Chebrolu1, Dattesh D. Shanbhag1, Aurelie Le Deley2, Sheshadri Thiruvenkadam1, Uday Patil1, 3, Patrice Hervo2, Sandeep N. Gupta4, Rakesh Mullick5

                                1Medical Image Analysis Lab, GE Global Research, Bangalore, Karnataka, India; 2GE Healthcare, Buc, France; 3Manipal Health Enterprises Pvt. Ltd., Bangalore, Karnataka, India; 4Biomedical Image Processing Lab, GE Global Research, Niskayuna, NY, United States; 5Diagnostics and Biomedical Technologies, GE Global Research, Bangalore, Karnataka, India

 

DCE-MRI is increasingly being used in diagnosis and screening of breast tumors. Careful study of intensity changes over time between the pre-contrast and post-contrast images is critical to tumor biometry. Rigid and non-rigid motion may be caused by factors such as voluntary patient motion, cardiac pulsation, and breathing during image acquisition. In this work we compare and evaluate b-splines and symmetric diffeomorphic normalization based non-rigid registration (NRR) algorithms for their effectiveness in motion correction for breast DCE-MRI. B-splines based NRR approaches provided consistent time performance. Better NRR accuracy was achieved with diffeomorphic normalization based motion correction methods.

                    1052.   Multi Slice-Group Slice-Accelerated Breast Diffusion MR Imaging on 3T

                                Sinyeob Ahn1, Himanshu Bhat1, Dorota Wisner2, Kawin Setsompop3, Thomas Benner4, Stephen Cauley3, Borjan Gagoski5, Bonnie Joe2, Gerhard Laub1, Vibhas Deshpande1

                                1Siemens Healthcare, San Francisco, CA, United States; 2Radiology and Biomedical Engineering, UCSF, CA, United States; 3Radiology, MGH, MA, United States; 4Siemens Healthcare, Erlangen, Germany; 5Children's Hospital, Boston, MA, United States

 

Brest diffusion MRI has been typically performed in an axial slice orientation with large FOV which tends to show ghosting artifacts from significant B0 field inhomogeneity. Sagittal slice orientation is limited due to long scan time. In this paper, we propose a multiple slice group slice-accelerated sequence for sagittal bilateral breast diffusion imaging. One slice on each slice group out of two was acquired and compared to the standard technique. The proposed method provided nearly identical image quality with almost half the scan time as compared to the standard bilateral diffusion imaging, suggesting a viable tool for breast lesion characterization within reasonable scan time.

                    1053.   Factors Affecting ADC Measures in Breast Cancer Patients

                                Shelley Waugh1, Lukasz Priba1, Sarah Vinnicombe2

                                1Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom; 2Division of Cancer Research, University of Dundee, Dundee, United Kingdom

 

The aim of this study was to identify the contribution of various factors that may have an impact on accuracy of measurements of apparent diffusion coefficients (ADC) in breast MRI.  We have considered the effect of long-term scanner stability, positional dependence within the coil, scan-scan repeatability and the effect of single and multiple observers on final measurements of whole tumour and lowest ADC values within tumours.  We conclude that scan-scan repeatability and scanner stability have minimal effect on measured ADC values and the biggest influence on measured ADC values is inter-observer repeatability.

 

                    1054.   DW-MP-SWIFT for High Spatial Resolution Diffusion Weighted Breast MRI

                                Curtis A. Corum1, Djaudat Idiyatullin1, Diane Hutter1, Lenore I. Everson1, Lynn E. Eberly2, Michael T. Nelson3, Michael Garwood1

                                1CMRR, Radiology, Medical School, University of Minnesota, Minneapolis, MN, United States; 2Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, United States; 3Breast Center, Radiology, Medical School, University of Minnesota, Minneapolis, MN, United States

 

This work describes a diffusion-weighted magnetization prepared SWIFT (SWeep Imaging with Fourier Transformation) sequence utilizing adiabatic RF pulses for diffusion weighting with additional fat suppression. The SWIFT sequence is used as excitation and high resolution readout of the prepared diffusion-weighted and fat-suppressed magnetization. The proposed method, DW-MP-SWIFT, is more robust to motion and eddy currents compared to typical diffusion-weighted sequences, while providing high spatial resolution. We report results of DW-MP-SWIFT for phantom and breast imaging of normal human subjects.

                    1055.   High Spatial Resolution DTI Sequence for Characterizing Breast Tumor Early Treatment Response: Comparison to Standard DTI Sequence

                                Lisa Wilmes1, Wei Ching Lo2, David C. Newitt2, Suchandrima Banerjee3, Evelyn Proctor2, Emine Saritas4, Ajit Shankaranarayanan3, Nola M. Hylton2

                                1University of California San Francisco, San Francisco, CA, United States; 2University of California San Francisco, CA, United States; 3Applied Science Laboratory GE Healthcare, CA, United States; 4University of California Berkeley, CA, United States

 

A high-resolution reduced field of view diffusion tensor weighted imaging sequence (HR-DTI), voxel size 4.8 mm3, was optimized for breast imaging and compared to a standard FOV DTI sequence (STD-DTI), voxel size 29.3 mm3, for evaluating tumor response to treatment in seven breast cancer patients undergoing neoadjuvant chemotherapy. Significant differences were found between the tumor  fractional anisotropy (FA)  measured by HR-DTI  and the STD-DTI prior to and early in treatment. Of the DTI parameters evaluated, HR-DTI FA correlated most strongly with tumor volume change post treatment. This preliminary study suggest that HR-DTI may be sensitive to treatment-induced changes in tumors.

                    1056.   Longitudinal Variation of Fibroglandular Tissue and Background Parenchymal Enhancement on Breast MRI in High-Risk Women: A Quantitative Assessment

                                Shandong Wu1, Wendie A. Berg2, Margarita L. Zuley2, Jules Sumkin2, Rachel C. Jankowitz3, David Gur4

                                1Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2Radiology, University of Pittsburgh Medical Center Magee-Womens Hospital, PA, United States; 3Oncology , University of Pittsburgh Medical Center Magee-Womens Hospital, PA, United States; 4Radiology, University of Pittsburgh, PA, United States

 

The purpose of this study is to perform quantitative assessment on the longitudinal variation of fibroglandular tissue (FGT) and background parenchymal enhancement (BPE) in sequential breast MRI scans for a cohort of high-risk women of developing breast cancer who did not undergo any specific risk-reduction intervention. We retrospectively analyzed 71 high-risk women each with two longitudinal cancer-free MRI scans using a fully automated computerized method. The preliminary results demonstrate the temporal variability of FGT and BPE, which may be useful as a reference measure when investigating these parameters as risk predictors and possibly as indicators of intervention-response in high-risk women.

                    1057.   Type Discrimination of Calcifications Using High-Pass Filtered Phase Images of Multiple Fast Field Echo Sequence

                                Katsuhiro Kida1, Sachiko Goto2, Tsutomu Kajitani1, Yoshiharu Azuma2

                                1Department of Radiology, Japanese Red Cross Okayama Hospital, Okayama-shi, Okayama, Japan; 2Faculty of Health Sciences, Graduate School of Health Sciences, Okayama University, Okayama-shi, Okayama, Japan

 

In this study, we discriminated the calcium oxalate and calcium phosphate in breast disease. A cup shaped gel phantom containing two types kidney stones was employed to simulate calcification in the breast. The phase values of five phase images with different echo times were measured, those were obtained by a 3D m-FFE sequence to shorten examination time. We conclude that the calcium oxalate and phosphate are distinguishable with the slope of linear approximation of calcifications on high-pass filtered phase images. We believe that this method is useful for the discrimination between benign and malignant breast disease.

                    1058.   Using MRI to Characterize Lymphatic Structure and Function Without Exogenous Contrast Agents

                                Paula Donahue1, Swati Rane2, Seth Smith2, Manus Donahue2

                                1Physical Medicine and Rehabilitation, Dayani Center for Health and Wellness, Vanderbilt University School of Medicine, Nashville, TN, United States; 2Radiology, Vanderbilt University School of Medicine, TN, United States

 

The overall objective of this work is to translate noninvasive imaging techniques for measuring brain structure and function to the lymphatic system to characterize axillary lymphatic vessel structure and interstitial protein accumulation in patients with breast cancer-related lymphedema (BCRL). To achieve this, a multi-faceted, noninvasive 3T MRI protocol for characterizing lymph node volume (DWIBS MRI), lymph vessel diameter (3D TSE), lymph flow velocity (spin labeling MRI), and interstitial protein accumulation (APT CEST MRI) are optimized and applied in healthy volunteers (n=10) and patients with BCRL (n=4).

Traditional Poster

Prostate Cancer

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1059.   Metabolomic Imaging for Human Prostate Cancer Detection Using MR Spectroscopy at 7-T

                                Romy Langhammer1, 2, Leo L. Cheng1, Johannes Nowak3, Shulin Wu1, W. Scott McDougal1, Chin-Lee Wu1, Eva M. Ratai1

                                1Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; 2Institute of Radiolgy, Department for Neuroradiology, University Hospital Wuerzburg, Wuerzburg, Bavaria, Germany; 3Institute of Radiology, Department for Neuroradiology, University Hospital Wuerzburg, Wuerzburg, Bavaria, Germany

 

The project aims to develop a non-invasive diagnostic test for prostate cancer. Metabolomic imaging maps of thirty whole prostates were created and analyzed, using magnetic resonance spectroscopy (MRS) at 7T. To test the functionality and reliability of this system, the outcome has been compared with the histopathology findings. In 61% of the samples, MRS detected cancer lesions in the same locations as were identified in the histopathology analysis; the histological regions that were not detected had significantly lower tumor volumes. Furthermore, a "Malignancy Index" can significantly differentiate between cancerous and benign MRS suspicious regions.

                    1060.   Fast 1H-MRSI of the Prostate with GOIA-SLASER Localization and Spiral Acquisition

                                Isabell K. Steinseifer1, Bart Philips1, Borjan Gagoski2, Marnix C. Maas1, Elisabeth Weiland3, Tom W.J. Scheenen1, Arend Heerschap1

ISMRM_MagnaLogo.jpg                                 1Radiology, Radboud University Medical Center, Nijmegen, Netherlands; 2Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States; 3MR Applications Development, Siemens AG, Healthcare Sector, Erlangen, Germany

 

Fast 1H MRSI of the prostate was achieved with a semi-LASER sequence with GOIA-WURST(16,4) refocusing pulses and spiral k-space sampling. The application of these low RF power demanding adiabatic pulses reduces the specific absorption rate so that an endorectal coil can be used to receive signal. Together with a relative short echo time of 90ms, a high SNR can be obtained. This can be translated in a much lower acquisition time, which can be realized because of the flexibility of spiral k-space sampling. The new sequence facilitates routine acquisition of metabolic data for clinical purposes.

 

 

                    1061.   Carbon Ion Radiation Therapy for Patients with Localized Prostate Cancer:

                                Maya B. Wolf1, Timur H. Kuru2, Gregor Habl3, Matthias C. Roethke1

                                1Radiology, DKFZ, Heidelberg, Baden-Württemberg, Germany; 2Urology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany; 3Radiation Oncology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany

 

Purpose was to assess T2- and diffusion-weighted imaging (DWI) after carbon ion therapy (CIT) of prostate cancer (PCa) for treatment monitoring. Multiparametric MRI including T2 and DWI at 3T were acquired prior to and following CIT in patients with histologically confirmed PCa.  Statistical analysis of region of interest data showed T2w signal loss at the 6 months interval and immediate, as well as, continuous apparent diffusion coefficient (ADC) increase after treatment in PCa areas. PSA was inversely correlated with ADC values. The results suggest that ADC could serve as an imaging biomarker for assessing therapeutic response of PCa to CIT.

 

                    1062.   Quantitative Evaluation of Diffusion Weighted Imaging Techniques for Radiotherapy of Prostate Cancer

                                Gary Liney1, 2, Thahabah Mohammed Al Harthi3, Ewa Juresic4, Lynette Cassapi4, Lois Holloway4, Mark Sidhom4, David Manton5, Peter Gibbs6

                                1Medical Physics, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia; 2Physics, University of Wollongong, Sydney, NSW, Australia; 3Physics, University of Sydney, NSW, Australia; 4Cancer Therapy Centre, Liverpool Hospital, NSW, Australia; 5Radiation Physics, East Riding, United Kingdom; 6University of Hull, East Riding, United Kingdom

 

The measurement of apparent diffusion coefficient (ADC) from diffusion weighted imaging (DWI) has been linked to tumour response following radiotherapy in prostate cancer. For it to be used to monitor and adapt plans during a course of treatment DWI needs to be produce reliable measurements and distortion free images. This work compares three DWI techniques in phantoms and prostate volunteers in order to assess their suitability for use as a robust clinical tool.

                    1063.   Multiparametric 3T Prostate MRI in Patients with Elevated PSA and No Previous Biopsy

                                Ivan Jambor1, Esa Kähkönen2, Pekka Taimen3, Harri Merisaari4, Jani Saunavaara5, Kalle Alanen6, Branislav Obsitnik7, Heikki Minn4, Viera Lehotska8, Hannu Aronen1

                                1Departement of Diagnostic Radiology, University of Turku, Turku, Finland; 2Department of Surgery, Turku University Hospital, Turku, Finland; 3Department of Pathology, University of Turku, Turku, Finland; 4Turku PET centre, University of Turku, Turku, Finland; 5Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland; 6Department of Pathology, Turku University Hospital, Turku, Finland; 7Department of Urology, St. Elisabeth Oncology Institute, Bratislava, Slovakia; 8Department of Radiology, St. Elisabeth Oncology Institute, Bratislava, Finland

 

Fifty-five patients with elevated PSA (>4 ng/ml), no previous biopsy and low risk of prostate cancer (PCa) underwent mpMRI at 2 institutions (41 at institution A and 14 patients at  institution B), consisting of anatomical T2-weighted imaging (T2wi), diffusion weighted imaging (DWI), proton magnetic resonance spectroscopy  and dynamic contrast enhanced MRI, using surface array coils followed by MRI targeted TRUS-guided biopsy in addition to 12 core systematic biopsy. The use of T2wi+DWI was shown to be an accurate tool for initial decision management and targeting biopsy in patients with elevated PSA.

                    1064.   Comparative Study of Four Widely Used Classifiers for Prostate Cancer Detection with Multi-Parametric MRI

                                Chengyan Wang1, Shuangjuan Cheng2, Juan Hu2, He Wang2, Xuedong Yang2, Jue Zhang, 13, Xiaoying Wang, 12, Jing Fang, 13

                                1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; 2Department of Radiology, Peking University First Hospital, Beijing, China; 3College of Enigneering, Peking University, Beijing, China

 

Prostate cancer (PCa) is the second most frequently diagnosed cancer and the sixth leading cause of cancer death among men worldwide [1]. Several studies [2-4] have proven that the diagnostic accuracy of PCa detection can be significantly improved by combining different MR sequences, and several computer-aided diagnosis (CAD) systems have been proposed to integrate the MR information. However, no comparison has been made to find out which system performs better. In this study, we evaluate the performance of four widely used classifiers using leave-one-out (LOO) method.MLP and SVM classifiers which have been successfully applied in many branches of medical diagnostics seem promising here. Because of their abilities to resolve nonlinear complex relations among input variables, without the need for any prior assumptions about these relations, MLP and SVM models are more advisable for PCa detection.

                    1065.   Handling Missing DCE Data in Prostate Cancer Detection Using Multiparametric MRI

                                Hussam Al-Deen Ashab1, Piotr Kozlowski1, Robert Rohling1, Purang Abolmaesumi1, Larry Goldenberg1, Mehdi Moradi1

                                1University of British Columbia, Vancouver, BC, Canada

 

The objective of the work presented here is to design classifiers to detect prostate cancer from MRI parametric maps with the capability of handling missing data, specifically DCE parameters. We propose two different methods and show their effectiveness in maintaining high AUC while handling missing parameters. Both methods are based on support vector machine classification. However, one method trains a single classifier and uses k-nearest neighbor imputation of DCE parameters in test cases where DCE is missing. The other method uses two different classifiers trained on DTI and DCE, fuses the two methods in cases where both DTI and DCE are available. We showed that as an increasing number of cases with missing DCE features are presented to the classifiers, KNN imputation of missing features outperforms the fusion of two classifiers. Both methods outperform a DTI only classifier.

                    1066.   Pixel-Wise Multi-Parametric Assessment of Prostate Cancer from Co-Registered Regions of Pathologically Defined Disease.

                                Chaitanya Kalavagunta1, Xiangmin Zhou2, Stephen Schmechel3, Joseph S. Koopmeiners4, Christopher A. Warlick5, Badrinath Konety5, Gregory J. Metzger1

                                1Center of Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 2Center for Research in Education and Simulation Technologies (CREST), University of Minnesota, MN, United States; 3Department of Laboratory Medicine and Pathology, University of Minnesota, MN, United States; 4Division of Biostatistics, School of Public Health, University of Minnesota, MN, United States; 5Institute for Prostate and Urologic Cancers, University of Minnesota, MN, United States

 

Our study shows the combined power of the multiparametric MRI parameters in the detection of prostate cancer and their association with grade. These results are highly unique and relevant as 1) Region of interest (ROI) definitions were dictated by registered pathology regions and not by manual interpretations of pathologically identified disease and 2) pixel-wise analysis was performed as opposed to the use of summary statistics from within the ROIs.  Performing a pixel-wise analysis allows the apparent non-coincidence of some of the quantitative MR parameters to be investigated. We propose this approach is a more appropriate way to apply predictive models moving forward.

                    1067.   Multiparametric MRI to Differentiate High-Risk from Low-Risk Prostate Cancer

                                Olga Starobinets1, Jeffry Simko2, 3, Kyle Kuchinsky2, John Kornak4, John Kurhanewicz, 15, Dan Vigneron, 15, Peter Carroll3, Kirsten Greene3, Susan Noworolski, 15

                                1Graduate Group in Bioengineering, University of California, San Francisco and Berkeley, San Francisco, CA, United States; 2Pathology, University of California, San Francisco, CA, United States; 3Urology, University of California, San Francisco, CA, United States; 4Epidemiology and Biostatistics, University of California, San Francisco, CA, United States; 5Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States

 

The purpose of this study was to use semi-quantitative and pharmacokinetically modeled parameters derived from dynamic contrast-enhanced (DCE) MRI, diffusion MR and MRI to differentiate high-risk from low-risk prostate cancers using digitally aligned whole-mount pathology as the standard of reference. High-risk prostate cancer had significantly lower ADC (p<0.05) and washout slope (p<0.05) than low-risk prostate cancer. A logistic regression combination of parameters provided improved discrimination (AUC=0.95). Without ADC, a combined model yielded AUC of 0.87 for discriminating high versus low risk prostate cancer.

                    1068.   Correlating Multi-Parametric MRI with Gleason Score in Human Prostate Cancer

                                Heling Zhou1, Rami R. Hallac2, Qing Yuan1, Yao Ding3, Franto Francis4, Robert D. Sims1, Ganesh Raj5, Ralph P. Mason1

                                1Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Analytical Imaging and Modeling Center, Children's Medical Center , Dallas, TX, United States; 3Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX, United States; 4Pathology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 5Urology, University of Texas Southwestern Medical Center, Dallas, TX, United States

 

Prostate cancer remains the most common malignant tumor in men. Hypoxia is an important prognostic biomarker. In this study, 10 patients with biopsy confirmed prostate cancer underwent MRI studies including oxygen enhanced (BOLD and TOLD), DCE, and diffusion weighted MRI. The multi-parametric maps were intercorrelated and compared with Gleason score. ADC and R2* were found to be significantly different from normal prostate and showed general trends of decrease with higher Gleason score. A multi-parametric approach is feasible and provides insights into tumor pathophysiology.

           

                    1069.   Prostate Cancer Detection from Contrast Enhanced T1 Time Course Without Pharmacokinetic Modeling

                                Nandinee Fariah Haq1, Piotr Kozlowski2, 3, Edward C. Jones4, Silvia D. Chang3, Larry Goldenberg2, Mehdi Moradi1

                                1Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada; 2Urologic Sciences, University of British Columbia, Vancouver, BC, Canada; 3Radiology, University of British Columbia, Vancouver, BC, Canada; 4Pathology and Laboratory Medicine, University of British Columbia, University of British Columbia, Vancouver, BC, Canada

 

In this work, we propose a data-driven approach to characterizing T1 time course. This method which is free of physiologic modeling is used to classify prostate tissue into cancer and normal, based on dynamic contrast enhanced T1-weighted images. The reference standard is the wholemount histopathologic analysis of extracted prostate specimens. Our approach is to design a learning agent that can detect cancer directly from the T1 time course without modeling the physical phenomenon. The dimensionality of the T1 time course is reduced using Principal Component Analysis (PCA) and the resulting parameters are used with Support Vector Machine Classification (SVM). An area under ROC of 0.87 is reported in pixel level classification.

                    1070.   Comparison of an Inflatable Single Loop and Rigid Dual Channel Endorectal Coil for Prostate Imaging at 3T.

                                Thiele Kobus1, 2, Andriy Fedorov1, Vera Kimbrell1, Tina Kapur1, Robert Mulkern3, Clare Tempany1

                                1Radiology, Brigham and Women's Hospital, Boston, MA, United States; 2Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 3Radiology, Children's Hospital, Boston, MA, United States

 

In this study, an inflatable single loop and rigid dual channel endorectal coil were compared for prostate imaging at 3T. Twenty-two patients were included and T1 weighted images were used for a SNR analysis. At close distances from the coil, the SNR in the prostate was higher for the rigid coil compared to the inflatable coil. The increase in SNR may be used to increase the spatial resolution of T2 weighted images, though in this study the 2.4 fold increase in in-plane spatial resolution led to image quality metrics somewhat less than those found with the inflatable coil.

                    1071.   The Effect of Varying Diffusion-Encoding Gradient Strength and Separation on Measured Apparent Diffusion Coefficient and T2 of Prostate

                                Shiyang Wang1, Yahui Peng1, 2, Milica Medved1, Steffen Sammet1, Ambereen Yousuf1, Weiwei Du1, 3, Yulei Jiang1, Gregory S. Karczmar1, Aytekin Oto1

                                1Department of Radiology, University of Chicago, Chicago, IL, United States; 2School of Electronic and Information Engineering, Beijing Jiaotong University, Bejing, China; 3Department of Information Science, Kyoto Institute of Technology, Kyoto, Japan

 

Hybrid DWI and T2 measurements showed improved contrast enhancement in prostate cancer diagnosis. The measured apparent diffusion coefficient can be affected by restricted diffusion, depending on the diffusion gradient separation (&#916;). The effect of diffusion gradient strength (g) and &#916; on prostate cancer diagnosis is unknown. Current study was performed in order to test whether acquisitions with longer &#916; are affected by restricted diffusion. ADC/T2s obtained with hybrid DWI sequences with fixed and non-fixed &#916;s were compared and no significant differences were found. Thus restricted diffusion does not affect the ADC values at the &#916; values used in hybrid imaging.

                    1072.   Triexponential Function Analysis on Diffusion-Weighted MRI in Diagnosing Prostate Cancer

                                Yu Ueda1, Satoru Takahashi2, Naoki Ohno3, Katsusuke Kyotani1, Nobukazu Aoyama1, Hideaki Kawamitsu1, Yoshiko Ueno2, Kazuhiro Kitajima2, Fumi Kawakami4, Tomoyuki Okuaki5, Toshiaki Miyati3, Kazuro Sugimura2

                                1Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan; 2Department of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan; 3Faculty of Health Sciences, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan; 4Department of Diagnostic Pathology, Kobe University Hospital, Kobe, Hyogo, Japan; 5Philips Healthcare  Asia Pacific, Minato-ku, Tokyo, Japan

 

To evaluate the clinical usefulness of triexponential function analysis of diffusion weighted MRI for the prostate cancer in the peripheral zone (PZ), we analyzed three diffusion coefficients (Dp, Df, Ds) and fractions (Fp, Ff, Fs), and compared them with the extra- and intracellular component information measured with the histopathological specimens and pharmacokinetic parameters calculated with DCE-MRI. Triexponential analysis would provide more detailed information on diffusion and perfusion of prostate cancer noninvasively. Moreover, our findings suggested that the reduction of ADC in PZ cancer would be due to the decrease of Ds that reflects intracellular diffusion.

                    1073.   Diffusion-Weighted Imaging of Prostate Cancer Using Statistical Model Based on a Gamma Distribution

                                Hiroshi Shinmoto1, Chiharu Tamura1, Shigeyoshi Soga1, Teppei Okamura1, Kentaro Yamada1, Tatsumi Kaji1, Koichi Oshio2

                                1Radiology, National Defense Medical College, Saitama, Japan; 2Diagnostic Radiology, Keio University, School of Medicine, Tokyo, Japan

 

The purpose of this study was to investigate the distribution of diffusion coefficients in prostate cancer (PC) and healthy peripheral zone (PZ) using the statistical model based on a gamma distribution. Twenty-six patients with PC were included in this study. The mean and the standard deviation were significantly lower in PC than in PZ. ADC < 1.0 (%) was significantly higher in PC than in PZ and ADC > 3.0 (%) was significantly lower in PC than in PZ. The statistical model provides additional insight for DWI and allows us better correlation of diffusion signal decay and histologic findings.

                    1074.   Quantitative DTI Tractography of Prostate Gland in Prostate Cancer Patients

                                Alexey A. Tonyushkin1, 2, Sandeep S. Hedgire1, Peter F. Hahn1, Shahin Tabatabaei1, Mukesh G. Harisinghani1, Andrew JM Kiruluta1, 2

                                1Radiology Dept., Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; 2Physics Dept., Harvard University, Cambridge, MA, United States

 

Diffusion tensor imaging (DTI) is commonly used to perform tractography that allows visualizing neuronal fiber map in a brain. This technique seldom been used for other visceral organs. We applied DTI tractography to prostate MRI and developed a quantitative approach that is able to discriminate tumor vs. normal tissue for diagnostic purposes. We carried out HIPPA compliant retrospective study of N=25 men with biopsy proven prostate cancer. The results imply differences in tract number in tumor vs. normal gland. Since these differences are statistically significant we can design a novel imaging tool to determine aggressiveness of tumor during diagnostics.

                    1075.   Rotating Frame Relaxation Measurements in Prostate Cancer Model

                                Hanne Hakkarainen1, Ivan Jambor2, Matti Poutanen3, Heidi Liljenbäck2, 3, Helena Ahtinen2, Anne Roivainen2, 3, Heikki Minn4, Miika Martikainen, Timo Liimatainen1

                                1 A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland; 2Turku PET Centre, University of Turku, Finland; 3Turku Center for Disease Modeling, University of Turku, Turku, Finland; 4Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland

 

Rotating frame relaxation times TRAFF2, TRAFF4, T1&#961;,CW, T1&#961;,adiab and T2&#961;,adiab were measured in subcutaneous prostate cancer (PC3-RFP) tumors in several time points. The data obtained serve as baseline of relaxation time constants for upcoming anticancer therapy follow up using the same animal model.

                    1076.   Aggressiveness Biomarker for Prostate Cancer in ADC-T2W MR Feature Space

                                Alpay Özcan1, Baris Türkbey2, Peter Choyke2, Seong K. Mun3

                                1Virginia  Polytechnic Institute and State University, Arlington , VA, United States; 2National Cancer Institute, Bethesda, MD, United States; 3Virginia  Polytechnic Institute and State University, Arlington, VA, United States

 

Accurate localization of prostate cancer (PCa) is fundamental for effective surveillance and, guiding diagnostic and therapeutic interventions. However, an imaging biomarker is absent for this goal. Herein, the ADC-T2W MR feature space (MR-FS) is proposed for image guided PCa strategies. An interactive in-house software was implemented to incorporate objectively and directly physician's experience into the discovery process.

The analysis of a 44 patient cohort revealed a specific region in MR-FS distinguishing aggressive from indolent PCa. By observing the pixels associated with the aggressive region, effective biopsy and therapy target localization and, active surveillance is achieved.

                    1077.   Track Density Imaging for High Resolution Diffusion Tractography in the Prostate with and Without Tumor

                                Michael Ohliger1, Cornelius Von Morze1, Antonio Westphalen1, Natalie Korn1, Christopher Hess1, Daniel Vigneron. 1, John Kurhanewicz1

                                1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

 

Track density imaging of the prostate with isotropic 300 &#956;m resolution was implemented at 3T. Imaging time was nearly identical to a clinical diffusion-weighted acquisition. A total of 19 patients have been imaged to date. At least two examples are seen of tumor interrupting tracks within the central gland. Further work will include pathologic validation to assess the physical basis of observed tracks.

Traditional Poster

Cancer: Cells, Biopsies & Biofluid

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1078.   Principal Component Directed Partial Least Squares Analysis for Differentiation of Benign and Malignant Canine Breast Cancer: HR-MAS NMR Spectroscopy-Based Metabolomic Study

                                Sang-Young Kim1, Taehyeong Lee2, Hyunju Kim3, Eunjung Bang3, Hwi-Yool Kim2, Bo-Young Choe1

                                1Department of Biomedical Engineering, The Catholic University of Korea, Seoul, Korea; 2Department of Veterinary Surgery, Konkuk University, Seoul, Korea; 3Korea Basic Science Institute, Seoul, Korea

 

In this study, we aimed to evaluate the potential use of HR-MAS NMR spectroscopy on intact tissue specimens as a tool for prediction of canine breast cancer malignancy through multivariate statistical analysis. HR-MAS MR spectra of surgically obtained three types (control, benign, malignant) of breast tissues were acquired. Metabolic profiles were examined using the multivariate statistical model (principal components analysis and orthogonal signal correction pretreated partial least square-discriminate analysis). Our findings demonstrated that PCA directed OSC-PLS-DA analysis using 1H HR-MAS MR metabolic profiles of breast tissues might be an effective diagnostic and prognostic tool for the treatment of breast cancer.

                    1079.   Metabolic Profiling of Urinary Bladder Carcinoma Tissues by HRMAS NMR Spectroscopy

                                Abhinav Arun Sonkar1, Shatakshi Srivastava2, Raja A. Roy3, Yadvendr A. Dheer1, Nuzhat A. Husain4

                                1Surgery, King George's Medical University, Lucknow, Uttar Pradesh, India; 2Center for Biomedical research,  SGPGI, Lucknow, Uttar Pradesh, India; 3Center for Biomedical research, SGPGI, Lucknow, Uttar Pradesh, India; 4Pathology, RMLIMS, Lucknow, Uttar Pradesh, India

 

In the present work, proton HR-MAS NMR spectroscopic studies of muscle non-invasive Urinary Bladder Carcinoma (UBC) tissue specimens with simultaneous urine analysis has been performed. The detailed metabolic profiling demonstrated significant presence of taurine and branched chain amino acids (BCAA) in tissues of 24 patients suffering from superficial UBC when compared with 29 tissue specimens from the same subjects with non-malignant biopsies. The proton NMR spectra were then subjected to PCA and PLS-DA multivariate analysis. The validated model allowed >85% correct classification of malignant tissues when compared with gold standard histopathological examinations.

                    1080.   Metabolic Characterization of Locally Advanced Breast Cancer in Response to NAC Treatment

                                Shiva Shojaei Moghaddam1, Maria D. Cao1, Guro F. Giskeødegård1, Hans E. Fjøsne1, Steinar Lundgren1, Per E. Lønning2, Tone F. Bathen1

                                1NTNU, Trondheim, Sør-Trøndelag, Norway; 2University of Bergen, Begren, Norway

 

Metabolic profiling has shown promise in breast cancer characterization. High resolution magic angle spinning  MR spectroscopy was performed on biopsies obtained before and after neoadjuvant chemotherapy in patients with locally advanced breast cancer. Quantitative metabolite concentrations were related to the treatment response and survival of the patients. Glycerophosphocholine, Glycine and myo-Inositol showed significant changes in response to NAC treatment among survivors, responders and non-responders.  Findings from this study indicate that the MR metabolic profile in response to NAC treatment can assist the prediction of prognosis and clinical treatment response in LABC patients.

                    1081.   NMR Spectroscopy Identifies Two Subtypes with Different Metabolic Profiles in Stem-Like Cells from Glioblastoma Multiforme

                                Alessandra Palma1, Sveva Grande1, Anna Maria Luciani1, Antonella Rosi1, Mauro Biffoni2, Lucia Ricci-Vitiani2, Daniele Runci2, Roberto Pallini3, Vincenza Viti, Laura Guidoni

                                1Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanità and INFN Sanità Group, Roma, Italy, Italy; 2Dipartimento di Ematologia, Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Italy, Italy; 3Dipartimento di Neurochirurgia, Università Cattolica del Sacro Cuore, Roma, Italy, Italy

 

Recurrence of the glioblastoma after conventional treatments is attributed to the overgrowth of stem-like cancer cells resistant to treatments. 1H NMR spectra run on glioblastoma derived stem-like cells grown in neurospheres showed intense signals common in brain and brain tumours including NAA, creatine, myoinositol, glutamine and neutral lipids. Unsupervised cluster analysis performed on spectral data of cells from 27 glioblastoma patients identified two different NMR-based groups with different metabolism. A mixed neural–astrocyte metabolic phenotype with a strong neuronal fingerprint prevailed in one group (15 cell lines) and an astrocytic/glioma-like metabolism was prevalent in the other cluster (12 cell lines).

                    1082.   Metabolic Profile of Human Breast Tissues Studied by In-Vitro NMR Spectroscopy

                                Naranamangalam R. Jagannathan1, Rani G. Sah1, Uma Sharma1, Rajinder Parshad2, Vurthaluru Seenu2

                                1Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, Delhi, India; 2Department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, Delhi, India

 

High-resolution in-vitro NMR spectroscopy was used to determine the absolute concentration of various metabolites in 23 breast tissues, both involved (n=11) and non-involved (n=13). One-dimensional and two- dimensional NMR experiments (DQF-COSY and TOCSY) were carried out at 400.13 MHz. The concentration of Lactate (14.0 ± 11.8 mmol/kg), Creatine (1.9 ± 1.2 mmol/kg), Choline (3.1 ± 2.2 mmol/kg), Glycerophosphocholine/Phosphocholine (5.2 ± 4.1 mmol/kg) and Glutamate/Glutamine (8.3 ± 5.4) mmol/kg in involved tissues were significantly higher compared to non-involved tissues, indicating a general increase in the metabolic activity in tumor tissues and thus providing an insight into the tumor metabolism.

                    1083.   Phospholipid Metabolism, But Not Energy Metabolism Is Affected by Expression of the Multidrug Resistance Transporter ABCB5 in G3361 Melanoma Stem Cells

                                Norbert W. Lutz1, Jie Ma2, Patrick J. Cozzone1, Markus H. Frank2

                                1CRMBM, Faculté de Médecine, Aix-Marseille University, Marseille, France; 2Transplant Research Program, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States

 

Synopsis

                    1084.   The Effect of Choline Kinase-α Inhibition on Lipid Metabolism of Breast Cancer Cells

                                Noriko Mori1, Flonné Wildes1, Kristine Glunde1, Zaver M. Bhujwalla1

                                1The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

 

Phosphatidylcholine has important roles in membrane structure and cell signaling. Increased levels of choline kinase (Chk)-&#945; and phosphocholine (PC) are consistently observed in aggressive cancers. Understanding the roles of Chk-&#945; in cancer can result in new therapies. We previously showed that the Chk-&#945; protein, but not PC was essential for cell survival of two triple negative breast cancer cell lines, MDA-MB-231 and SUM149, using a Chk-&#945; inhibitor which reduces PC but not Chk-&#945; protein. Here we have investigated lipid metabolism in these breast cancer cells and identified PtdCho as an important factor in breast cancer cell survival.

                    1085.   Metabolic Analysis of Slowly Cycling Melanoma Cells

                                Sergey Magnitsky1, Geetha Mohan1

                                1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

 

Low efficacy of existing treatment for various human cancers has been attributed to the existence of cancer stem cells. Such slowly cycling sub-population of cells in melanoma exhibits high tumorigenicity, self-renewal capacity and drug resistance. The goal of this study was to delineate metabolic differences between slowly cycling sub-population and bulk tumor cells. Ethanol/chloroform cells extracts were prepared from sorted cells.  High-resolution NMR spectra were acquired. NMR data revealed high intracellular lactate and choline concentration in slowly cycling sub-population cells compared to fast cycling tumor cells. Approximately 70% of lactate produced in unsorted cells was produced by slowly cycling sub-population.

                    1086.   Role of Choline Kinase and Ethanolamine Kinase Isoforms in Modulating Phosphoethanolamine Levels in Breast Cancer Cells

                                Tariq Shah1, Balaji Krishnamachary1, Flonne Wildes1, Jannie Wijnen2, Kristine Glunde1, Zaver M. Bhujwalla1

                                1Division of Cancer Imaging Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, United States; 2Cancer center, University Medical Centre Utrecht, Utrecht, Netherlands

 

While significant effort has been focused on the increased phosphocholine (PC) levels observed in cancer cells and tumors, increased phosphoethanolamine (PE) has been underexplored.  Increased PC, but not PE, is observed in cells in culture because culture medium contains free choline, but no ethanolamine.  We have used siRNAs to silence specific genes involved in choline and ethanolamine metabolism to understand their roles in intracellular metabolite levels measured with high-resolution phosphorus MR spectroscopy of cell extracts.  We have demonstrated that both Chk-&#945; and EthnK1 contribute to PE levels observed in vivo with the latter having a primary role in its biosynthesis.

 

                    1087.   CEST Imaging of Human Breast Cancer Cells

                                Catherine DeBrosse1, Mohammad Haris1, Ravi Prakash Reddy Nanga1, Hari Hariharan1, Damodar Reddy1, Imran Mohammad2, Kejia Cai1, Anup Singh1, Ravinder Reddy1

                                1Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Department of Pharmacology and Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, PA, United States

 

The purpose of this study was to determine feasibility of glutamate chemical exchange saturation transfer (GluCEST) imaging in human breast cancer cell lines treated with poly-L-glutamate (PLG). PLG has been used as a drug-conjugate in recently developed cancer therapies, as it is broken down by tumor proteases. Glutamate fragments that result from PLG degradation have labile amine protons that exchange with water and give GluCEST signal. In this study, we demonstrate that treatment of human breast cancer cells with PLG led to an increase in GluCEST signal due to the breakdown of PLG by tumor proteases such as cathepsins.

                    1088.   The Effect of Aminooxyacetate on Metabolism of Breast Cancer Cells

                                Noriko Mori1, Preethi Korangath2, Santosh Bharti1, Flonné Wildes1, Saraswati Sukumar1, 2, Zaver M. Bhujwalla1, 2

                                1The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

 

Aminooxyacetate (AOA) is a known inhibitor of the transamination reaction. We previously found that AOA treatment showed dose dependent growth inhibitory activity in breast cancer cells, especially in glutamine dependent cancer cells such as SUM159.  To investigate the mechanism of AOA action, we used 1H MRS of cell extracts and conditioned media from SUM159 and observed reductions of alanine, aspartate, phosphocholine, and increases of glutamate and tyrosine following treatment with 2mM AOA for 24h.  Lactate production and glucose consumption in conditioned media and the level of Chk-&#945; that catalyzes the formation of phosphocholine were not affected by AOA.

                    1089.   Role of Lymphatic Endothelial Cells in Prostate Cancer Cell Invasion in Tumor Microenvironments

                                Tariq Shah1, Flonne Wildes1, Dmitri Artemov1, Zaver M. Bhujwalla1

                                1Division of Cancer Imaging Research, Department of Radiology and Radiological Sci, Johns Hopkins University, Baltimore, MD, United States

 

While the presence of lymph node metastasis as a major prognosticator for many cancers, including prostate cancer, is well established, the regulation of tumor-associated lymphangiogenesis and the microenvironmental factors that affect the invasion of cancer cells into lymphatic vessels requires additional investigation.  Here we have investigated the role of lymphatic endothelial cells prostate-cancer cell interaction in the invasion and degradation of the extracellular matrix (ECM) under normoxic and hypoxic environments using our MR compatible cell perfusion assay, and determined the associated metabolic changes.

Traditional Poster

Tumor Perfusion & Permeability: Applications

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1090.   Initial Experience: Combination of MR Pharmacokinetic Modeling and FDG Uptake Using Simultaneous Dynamic Contrast Enhanced MRI and PET Imaging

                                Nathaniel E. Margolis1, Linda Moy1, Akshat C. Pujara1, Alana Amarosa1, Eric E. Sigmund1, Christian Geppert2, Christopher Glielmi2, Melanie Freed1, Li Feng1, Ricardo Otazo1, Amy N. Melsaether1, Sungheon Kim1

                                1Radiology, NYU Langone Medical Center, New York, United States; 2Siemens Medical Solutions, New York, United States

 

The objective of our study was to assess the feasibility of using DCE-MRI and PET data for the assessment of breast cancer MR pharmacokinetics and metabolic activity. A whole-body integrated 3 T PET/MR scanner was used to simultaneously acquire DCE-MRI and PET images of the breast in the prone position. We found trends between DCE-MRI kinetic model parameters, metastatic burden, and progesterone receptor status. Our preliminary results demonstrate the feasibility of using simultaneous acquired DCE-MRI and PET measures for better characterization of breast lesions.

                    1091.   Simulation Analysis of Region-Of-Interest Measurement Errors on Parameter Maps Derived from Dynamic Contrast-Enhanced MRI and T1 Mapping of Small Volume Breast Cancer

                                Moira C. Schieke1

                                1Lakeshore, Milwaukee, WI, United States

 

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                    1092.   Evidence of Intra-Patient and Inter-Patient  Heterogeneity in the Microvasular Characteristics of Colorectal Cancer Liver Metastases

                                Laura Horsley1, Neil Thacker2, Ross Little3, Yvonne Watson3, Sue Cheung3, Geoff Parker3, Gordon Jayson1, Alan Jackson2

                                1Institute for Cancer Studies Christie Hospital NHS Foundation Trust, University of Manchester, Manchester, United Kingdom; 2Wolfson Molecular Imaging Centre, University of Manchester, Manchester, Greater Manchester, United Kingdom; 3Centre for Imaging sciences & Biomedical Imaging Institute, University of Manchester, United Kingdom

 

This study used DCE-MRI to compare the microvascular characteristics of liver secondaries in patients with advanced colorectal cancer. We particularly wished to demonstrate whether differences could be detected between liver secondaries in the same patient or between liver secondaries in different patients, using standard DCE-MRI techniques employed for clinical trials. In order to test this hypothesis we developed a statistical method which incorporated information on the measurement reproducibility and error for median values of parameters Ktrans, ve, vp, EF and ADC.   There was more variability between liver secondaries in different patients than there was between secondaries in the same patient.

                    1093.   Extramural Depth of Tumor Invasion at Thin-Section MR in Rectal Cancer: Associating with Prognostic Factors and ADC Value

                                Tong Tong1, Yajia Gu1, Weijun Peng1, He Wang2

                                1Cancer Hospital, Shanghai, China; 2MR Research China, GE Healthcare, Shanghai, China

 

To assess the value of maximal extramural depth (EMD) of T3 tumor spread on MRI as a potential noninvasive imaging biomarker of tumor aggressiveness in rectal cancer.Tumor EMDs differ between CEA <5 ng/mL versus¡Ý5 ng/mL(P=0.013), CA19-9<27U/mL versus¡Ý27 U/mL(P=0.012) , the groups of cN0 versus cN+ cancers (P=0.049), and between the several groups of histological differentiation grades (P=0.033).A significant negative correlation (r=-0.581; P=0.001) between ADC and EMD values was found. Significant correlations were found between EMD values and CEA,CA19-9 level, differentiation grade and ADC value. EMD has the potential to become an imaging biomarker of tumor aggressiveness profile.

                    1094.   Pulsed-Continuous Arterial Spin Labeling MRI with Multiple Post-Labeling Delay in Renal Cell Carcinoma: Clinical Feasibility and Initial Results of a Comparative Study with Parametric Dynamic Contrast-Enhanced MRI

                                Nobuyuki Kosaka1, Katsuki Tsuchiyama2, Kazuhiro Shimizu1, Yasuhiro Fujiwara3, Tsuyoshi Matsuda4, Tatsuya Yamamoto1, Tatsuro Tsuchida1, Nobuyuki Oyama2, Hirohiko Kimura1

                                1Department of Radiology, University of Fukui, Eiheiji, Fukui, Japan; 2Department of Urology, University of Fukui, Eiheiji, Fukui, Japan; 3Radiological Center, University of Fukui Hospital, Eiheiji, Fukui, Japan; 4Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan

 

Pulsed-continuous arterial spin labeling MRI (pcASL) with multiple post-labeling-delay to measure arterial transit time-corrected tumor blood flow (ATC-TBF) in renal cell carcinoma was performed and compared to parametric dynamic contrast-enhanced MRI (DCE-MRI). All image acquisitions and data post-processings were successfully achieved in all 6 patients, and high signals of 5 clear cell carcinomas were visually identified. Both maximum slope and contrast enhancement ratio correlated significantly with ATC-TBF. Ktrans, ve, and IAUGC90@showed positive but non-significant correlations. pcASL with multiple PLD appears clinically feasible for measuring ATC-TBF, which correlated with several hemodynamic parameters of DCE-MRI.

 

                    1095.   Quantitative Perfusion and Diffusion Weighted Magnetic Resonance Imaging of Pancreatic Adenocarcinoma: A Pilot Study

                                Hyunki Kim1, Pablo Arnoletti2, John Christein1, Marty Heslin1, James Posey1, Amol Pednekar3, T. Beasley1, Desiree Morgan1

                                1University of Alabama at Birmingham, Birmingham, AL, United States; 2Center for Specialized Surgery, FL, United States; 3Philips Medical Systems, WA, United States

 

Breath-hold DCE-MRI/DWI was applied for 16 patients with treatment-naïve pancreatic adenocarcinoma.  The physiological parameters such as Ktrans, kep and ADC values in pancreatic tumors, non-tumor adjacent pancreatic parenchyma (NAP), liver metastases, and normal liver tissues were quantitated.  Ktrans, kep and ADC values of pancreatic tumors were significantly lower than those of non-tumor adjacent pancreatic parenchyma. Thus, the perfusion and diffusion parameters may be utilized as diagnostic markers for pancreatic cancer detection.

                    1096.   Local Vascular Input Function for Pharmacokinetic Modeling of Prostate Cancer

                                Hatef Mehrabian1, Masoom A. Haider2, Anne L. Martel1

                                1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 2Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

 

A major component in multi-parametric MRI of tumors is pharmacokinetic modeling of their DCE-MRI which provides information about perfusion and vascular permeability. Such analysis requires an AIF that is approximated outside of the tissue and is a major source of error and discrepancy among studies. Using a local vascular input function (VIF) instead has the potential to improve PK analysis. This paper investigates the effects of using VIF (in 19 prostate DCE-MRI datasets) and shows more consistent PK parameters are obtained for normal peripheral zone tissue compared to using AIF and result in better separation of tumor and normal tissues.

                    1097.   Repeatability of DCE-MRI Parameters in a Paediatric Oncology Population

                                Neil P. Jerome1, Keiko Miyazaki1, David J. Collins1, Matthew R. Orton1, James d'Arcy1, Lucas Moreno2, 3, Andrew D J Pearson2, 3, Lynley V. Marshall2, 3, Fernando Carcellar2, 3, Martin O. Leach1, Stergios Zacharoulis2, 3, Dow-Mu Koh4

                                1CR-UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 2Paediatric Drug Development Team, Cancer Therapeutics and Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 3Paediatric Drug Development Unit, Children and Young People's Unit, The Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 4Department of Radiology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom

 

It is essential that functional imaging-derived biomarkers have acceptable repeatability in order to have confidence in measured changes. Where paediatric populations may exhibit varying physiology/metabolism to adults, there is a need to specifically assess repeatability of DCE-MRI in a paediatric population. For a paediatric cohort (median age 11, range 6 – 15 years) of five extra- and seven intra-cranial solid tumours, DCE was performed on two successive days, with analysis using cohort-derived AIF and extended Tofts model. Both model-derived and model-independent parameters showed acceptable repeatability (CV<20%), with native T1 and IAUGC60 performing best (CV 6.2 % and 12.8 % respectively).

                    1098.   Comparison of Patient-Specific and Fixed Arterial Input Functions for Assessing Treatment Response at DCE-MRI

                                Mihaela Rata1, Matthew R. Orton1, Christina Messiou1, Elly Castellano1, Helen Young2, Nandita de Souza1, David J. Collins1, Martin O. Leach1

                                1CRUK and EPSRC Cancer Imaging Centre, Institute of Cancer Research & Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 2Early Clinical Development, AstraZeneca, Macclesfield, United Kingdom

 

Accurate AIF measurement in DCE-MRI studies is challenging due to various confounding factors: in clinical trials looking at treatment response a fixed AIF is often used.  Whilst this removes a major source of variation, if the treatment affects the AIF, such changes will be erroneously reflected in the tissue parameters.  This abstract compares the repeatability and treatment effect of Ktrans obtained using three AIFs:  fixed AIF; AIF from a vessel in the DCE-MRI data; AIF obtained on the same day with a DC-CT examination.  A fixed AIF is most repeatable, but the DC-CT AIF has a more significant treatment effect.

                    1099.   In Vivo Assessment of Non-Small Cell Lung Cancer: Detection of Early Response to Concurrent Chemoradiotherapy by Using Breath-Hold Dynamic Contrast Enhanced MRI

                                Xiuli Tao1, Han Ouyang1, Feng Ye1, Zihua Su2, Xiao Xu2, Ning Wu1

                                1Cancer Hospital£¬Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; 2GE Healthcare, Beijing, China

 

DCE-MRI has been extensively used in monitoring treatment response on many anatomies. However, this technique was not fully explored in lung cancer due to breathing motion. In this paper, we demonstrated by using a mutual information based nonlinear registration scheme and two compartment Tofts model, clinical relevant parameters could be extracted from a breath-hold DCE-MRI to monitor treatment response on NSCLC.

                    1100.   The Response to Chemotherapy of Mesothelioma Tumours as Assessed by Dynamic Contrast-Enhanced MRI: First Impressions

                                Andrew B. Gill1, 2, Andrew N. Priest2, Nagmi Qureshi1

                                1Radiology, Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom; 2Medical Physics, Cambridge University Hospitals, Cambridge, United Kingdom

 

Mesothelioma has rarely been the subject of DCE-MRI investigations. This study applies pharmacokinetic modeling to DCE-MRI data acquired in patients with mesothelioma tumours to generate parameters associated with tumour perfusion (e.g. Ktrans, vp). Results from examinations before and after chemotherapy are reported in this abstract. Initial findings indicate that changes in Ktrans may correlate well with the response to treatment as evaluated by standard CT RECIST measures. Further patient numbers are needed to confirm these early impressions.

                    1101.   Model Independent Method on Modified DCE-MRI Perfusion Data for Exploring Area and Grade of Gliomas

                                Bob L. Hou1, Alice B. Lai2, Guodong Guo2, Jeffrey S. Carpenter1

                                1Radiology, WVU, Morgantown, WV, United States; 2Computer and EE, WVU, Morgantown, WV, United States

 

A common approaching to find brain tumor area and grade it from DCE-MRI perfusion data is to get the maps of volume transfer constant (Ktrans) and fractional extracellular-extravascular space volume (Ve) from pharmacokinetic models.  However there are questions on the models, and by using the models is very difficult to distinguish the Grade III with the Grade IV gliomas. In this study, we sought to apply a model independent method, i.e., Probabilistic Independent Component Analysis (PICA), on modified DCE data for finding the tumor areas and distinguishing their grades.

                    1102.   Assessing the Effects of Decreasing Temporal Resolution on Pharmacokinetic Analysis Using a Local Vascular Input Finction

                                Hatef Mehrabian1, Masoom A. Haider2, Anne L. Martel1

                                1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 2Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

 

Pharmacokinetic (PK) analysis of tumor DCE-MRI provides information about its vasculature. Such analysis requires an AIF, which has a narrow temporal profile, and its measurement requires data with high temporal resolution (resulting in low spatial resolution images). This paper investigates possibility of using a local vascular input function (VIF) that has a wider temporal profile and can be measured in low temporal resolution datasets, in PK analysis and shows VIF-based PK parameters are less sensitive to low temporal resolution compared to AIF-based parameters. Lowering temporal resolution enables imaging with high spatial resolution which improves both VIF calculation and PK analysis.

                    1103.   A Novel and Affordable DCE-MRI Phantom: Experimental Setup and Assessment of Reproducibility

                                Hector Sanchez Casas1, Araminta E. W. Ledger1, Craig Cummings1, Maria A. Schmidt1, Martin O. Leach1, Marco Borri1

                                1CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden, Sutton, Surrey, United Kingdom

 

DCE-MRI has an established role as both a diagnostic and research tool. This work presents a novel DCE-MRI test object of simple and affordable design, which can create reproducible dynamic enhancement curves employing commonly available automated contrast agent injectors.

A reproducible reference dynamic enhancement curve is a valuable tool in routine QA and can be employed to investigate the effect of MR sequence alterations on curve shape.

                    1104.   Adaptive Spatio-Temporal Resolution for Accelerated (ASTRA) DCEMRI Driven by Pharmacokinetic Modelling

                                Rashmi Reddy1, Shasmshia Tabassum1, Shaikh Imam1, Nithin N. Vajuvalli1, Sowmya Ramachandra1, Sairam Geethanath1

                                1Medical Imaging Research Center, Dayananda Sagar Institutions, Bangalore, karnataka, India

 

The proposed algorithm is based on an application of compressed sensing (CS) on dynamic contrast enhancement MRI (DCE-MRI). It involves the adaptive undersampling technique wherein the acquisition of more number of frames during the uptake aid to the improved Ktrans value and the high resolution images obtained during wash out aid in the improved Ve value. The technique is carried out on Qiba dataset (QIBA_v7_Tofts) by using a variable density Poisson mask for undersampling the k-space data. The proposed algorithm reconstructs the data by using combinations of the different acceleration factors viz. 1X, 2X, 4X, 6X and 6X/4X, as a result of which we are able to obtain better parametric maps with reduction in acquisition time. The quality of the reconstructed results is validated by calculating the NMRSE values and parametric maps for the data with different acceleration factors.

                    1105.   Error Quantification in Relaxivity Rate Change (Δ) Due to Systematic Errors in Dynamic Contrast Enhanced MR Studies

                                Hassan Bagher-Ebadian1, 2, Siamak P. Nejad-Davarani3, 4, James R. Ewing, 23, Hamid Soltanian-Zadeh1, 5

                                1Radiology, Henry Ford Hospital, Detroit, MI, United States; 2Physics, Oakland University, Rochester, MI, United States; 3Neurology, Henry Ford Hospital, Detroit, MI, United States; 4Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States; 5CIPCE, ECE Dept., University of Tehran, Tehran, Iran

 

In Dynamic Contrast Enhanced (DCE) MR studies, assessment of systematic errors propagated in longitudinal relaxation rate change, &#8710;R1(t), is important since errors in &#8710;R1(t) profile, biases permeability parameters estimated in DCE-MR-Pharmacokinetic analysis. Herein, we asses and quantify the biasing of &#8710;R1(t)  profile at different enhancement-ratios in the DCE-T1 (3D-Spoiled-Gradient-Echo) experiment. Biasing arises from the deviation of actual-to-nominal dynamic-flip-angle and also the systematic error in estimating of resting T1 in Variable-Flip-Angle experiments prior to the contrast agent administration. Results imply that &#8710;R1(t), regardless of its enhancement ratio, is more susceptible to the underestimations of T1 and dynamic-flip-angel compared to their overestimations

Traditional Poster

Tumor Therapy Response: Clinical & Preclinical

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1106.   Spatial Heterogeneity Analysis of DCE- And DW-MRI Using the Logistic Ridge Regression to Predict Breast Cancer Response to Neoadjuvant Therapy

                                Xia Li1, Hakmook Kang1, Lori R. Arlinghaus1, A. Bapsi Chakravarthy1, Richard G. Abramson1, Vandana Abramson1, Thomas E. Yankeelov1

                                1Vanderbilt University, Nashville, TN, United States

 

DCE- and DW-MRI have been used to predict the response of breast tumors to neoadjuvant chemotherapy (NAC). However, most studies quantify changes in parameters averaged over the tumor ROI and therefore discard all spatial information related to tissue heterogeneity. In this study, a novel voxel-by-voxel analysis based on a logistic ridge regression model was employed to optimize the ability of DCE- and DW-MRI to predict the response of breast tumors to NAC. The results indicate that incorporating changes in the spatial heterogeneity in DCE- and DW-MRI data improves the ability to predict treatment response for breast cancer patients receiving NAC.

 

                    1107.   Diffusion Weighted MRI for Radiotherapy Treatment of Locally Advanced Cervical Cancer – Treatment Response Assessment Using Different Segmentation Methods

                                Søren Haack1, Kari Tanderup2, Jesper Folsted Kallehauge3, Jacob Christian Lindegaard2, Erik Morre Pedersen4, Sune Nørhøj Jespersen5, 6

                                1Dept. of Clinical Engineering, Aarhus University Hospital, Aarhus, Denmark; 2Dept. of Oncology, Aarhus University Hospital, Aarhus, Denmark; 3Dept. of Medical Physics, Aarhus University Hospital, Aarhus, Denmark; 4Dept. of Radiology, Aarhus University Hospital, Aarhus, Denmark; 5CFIN/MindLab, Aarhus University, Aarhus, Denmark; 6Dept. of Physics and Astronomy, Aarhus University, Aarhus, Denmark

 

Diffusion weighted MRI has shown great potential in diagnostic cancer imaging and may also have value for monitoring tumor response during radiotherapy. Before DW MRI can be used for monitoring treatment response objective methods for segmentation of the hyper-intense signal of the tumor at high b-value images should be evaluated. This study evaluates three objective segmentation methods used for monitoring treatment response of twelve patients with advanced cervical cancer treated with external beam radiotherapy followed by brachytherapy. Segmented volume, resulting mean ADC and histogram analysis are compared and evaluated.

                    1108.   Repeatability of Geometrically Corrected DWI Scans for Treatment Response Monitoring in Oesophageal Cancer

                                Astrid L.H.M.W. van Lier1, Peter S.N. van Rossum1, 2, Gert J. Meijer1, Cornelis A.T. van den Berg1, Mariëlle E.P. Philippens1, Jan J.W. Lagendijk1, Marco van Vulpen1, Irene M. Lips1

                                1Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2Surgery, UMC Utrecht, Utrecht, Netherlands

 

Prior to constructing a model for DWI-based response prediction in esophageal cancer, we investigated the repeatability of the ADC determination in the tumor. As the DWI images are geometrically distorted, we opted for retrospective correction of the maps prior to analysis. The coefficient of repeatability was found to be 11.0% (Bland-Altman analysis). No significant correlation was found between the ADC repeatability error and mean pixel shift. The repeatability error was generally smaller than the pre-per and pre-post treatment ADC difference (8/11 cases). We will continue to use the proposed DWI protocol for development of a treatment response prediction model.

                    1109.   ADC Histogram Analysis: Investigation of Treatment Response and Survival in Advanced Ovarian Cancer

                                Andrew Nicholas Priest1, Andrew J. Patterson1, Masako Y. Kataoka1, Ilse Joubert1, Mary A. McLean2, Martin John Graves1, Charlotte Hodgkin2, Robin A. Crawford3, Helena M. Earl3, John R. Griffiths2, James D. Brenton2, 3, David John Lomas1, Evis Sala1

                                1Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, United Kingdom; 2Cancer Research UK Cambridge Institute, Cambridge, United Kingdom; 3Oncology and Gynaecological Oncology, Addenbrooke's Hospital, Cambridge, United Kingdom

 

Diffusion-weighted imaging was used to assess treatment response in advanced ovarian cancer. Histogram analysis can potentially give more information about heterogeneous tumours than mean values. This study investigated, for both primary ovarian tumours and metastatic disease, how ADC histogram parameters change with neoadjuvant chemotherapy, and their relationships to treatment response and survival. Highly significant changes were found for the primary tumour in responders but not non-responders, with significantly greater changes in responders for the mean, 75th and 90th percentiles. However, no significant differences or changes were found for metastatic lesions. No relationship with survival was found for any lesion.

                    1110.   Functional Diffusion Mapping (FDM) for Quantitative DW-MRI to Predict Breast Cancer Response to Neoadjuvant Chemotherapy

                                Xia Li1, Lori R. Arlinghaus1, A Bapsi Chakravarthy1, Richard G. Abramson1, Vandana Abramson1, Thomas E. Yankeelov1

                                1Vanderbilt University, Nashville, TN, United States

 

DW-MRI has been used to predict treatment response in breast cancer. Studies have shown the ability of the functional diffusion mapping (fDM) method applied on DW-MRI as an early biomarker for survival for patients with brain tumor. However, there is only one study reporting the fDM analysis on breast cancer data. In this study, we attempted to determine 1) if fDM performed on patients with breast cancer can be used to separate responders from non-responders, and 2) does the fDM approach outperform simple region of interest based analysis. The results indicate that the fDM approach on the DW-MRI breast data retains the information of tumor heterogeneity, therefore allowing for an improved ability to predict treatment response when compared to a standard region of interest based analysis.

 

           

                    1111.   1.0T MR-Based Treatment Planning for Spinal Stereotactic Radiosurgery – Initial Case Study

                                Ning Wen1, Joshua Kim1, Carri Glide-Hurst1, Bo Zhao1, Yimei Huang1, David Hearshen2, Milan Pantelic2, M.Salim Siddiqui1, Kenneth Levin1, Benjamin Movsas1, Indrin Chetty1, Samuel Ryu1

                                1Radiation Oncology, Henry Ford Health System, Detroit, MI, United States; 2Radiology, Henry Ford Health System, Detroit, MI, United States

 

This study is to investigate the feasibility of developing a stereotactic radiosurgery treatment protocol for spinal metastatic lesions based solely on a dedicated 1.0 T magnetic resonance simulation platform. The dose was calculated on a synthetic CT image set generated from a weighted combination of T1-weighted and T2-weighted images for one patient. The dose calculation difference between CT and synthetic CT was within 3%. However, the bony segmentation, metal artifacts and geometric distortion correction need to be further investigated to use MRI as the primary imaging modality for spinal radiosurgery.

                    1112.   T Mapping for the Evaluation of High Intensity Focused Ultrasound Tumor Treatment

                                Stefanie JCG Hectors1, 2, Rik PM Moonen1, 2, Gustav J. Strijkers1, 2, Klaas Nicolay1, 2

ISMRM_MagnaLogo.jpg                                 1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Center for Imaging Research and Education, Eindhoven, Netherlands

 

This study was aimed to assess the effects of HIFU treatment on tumor T1&#961;. T1&#961; measurements at various spin-lock amplitudes (0-2000 Hz) were performed before, directly after and 3 days after HIFU treatment of murine tumors. The tumor T1&#961; at spin-lock amplitudes higher than or equal to 100 Hz significantly decreased at 3 days after HIFU compared to pre-treatment. The T1&#961; decline after HIFU became significantly larger with increasing spin-lock amplitudes, indicative of increased contrast between HIFU-treated and non-treated tissue at higher spin-lock amplitudes. Altogether, the data suggest that T1&#961; is a suitable biomarker for the evaluation of HIFU treatment.

                    1113.   Monitoring Therapeutic Effect of a Vascular Disrupting Agent: Correlation Between Perfusion Parameters Derived from Intravoxel Incoherent Motion Diffusion-Weighted Imaging and Dynamic Contrast Enhanced MRI

                                Ijin Joo1, Jeong Min Lee1, Joon Koo Han1, Byung Ihn Choi1

                                1Seoul National University Hospital, Seoul, Korea

 

Dynamic contrast enhanced (DCE) MRI has been widely used for noninvasive assessment of the change in tumor perfusion. Recently, intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) by using a bi-exponential fitting of the DWI data from multiple b-values has been reported to be useful for quantitative measurement of tumor perfusion without requirement of contrast medium. Our study using a rabbit liver tumor model demonstrated significant correlation between serially measured perfusion parameters derived from IVIM-DWI and DCE-MRI in the vascular disrupting agent (VDA)-treated group. Therefore, IVIM-DWI may be a useful surrogate of DCE-MRI in the longitudinal monitoring therapeutic effect of VDAs.

                    1114.   Targeting Choline Phospholipid Metabolism: GDPD5 and GDPD6 Silencing Decreases Breast Cancer Cell Proliferation and Invasion

                                Maria Dung Cao1, 2, Menglin Cheng2, Lu Jiang2, Tiffany R. Greenwood2, Balaji Krishnamachary2, Zaver M. Bhujwalla2, Tone F. Bathen1, Kristine Glunde2, 3

                                1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 3Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, United States

 

Here we investigated the effects of targeting choline phospholipid metabolism using GDPD5 and GDPD6 siRNA in two breast cancer cell lines, MCF7 and MDA-MB-231. Our study shows that GDPD5 and GDPD6 siRNA treatment increases glycerophosphocholine levels, decreases proliferation and invasion, but did not cause apoptosis. The effect of GDPD5 siRNA on cell proliferation was more severe in the less malignant breast cancer cell line. Decreased cell invasion was observed in GDPD5 compared to GDPD6 siRNA treated cells. Our results suggest that GDPD5 and GDPD6 silencing alone/combined can have a potential role as new molecular targets for treatment of breast cancer.

                    1115.   Steady-State Susceptibility Contrast MRI Detects Early Anti-Angiogenic Effects of a Novel Biomimetic Peptide in a Human Breast Cancer Model

                                Eugene Kim1, Esak Lee1, Charlesa Plummer2, Stacy Gil1, Alexander S. Popel1, Arvind P. Pathak2

                                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

 

Steady-state susceptibility contrast (SSC)-MRI is a clinically translatable technique that is used to measure vascular morphology. We show here that a novel biomimetic peptide we developed produced strong anti-angiogenic effects in an orthotopic human breast cancer model. SSC-MRI was able to detect treatment-induced decreases in blood volume and vessel caliber before the manifestation of significant differences in tumor growth and cellularity (conventional markers of therapeutic efficacy) between treated and control groups. This suggests that SSC-MRI provides promising biomarkers of early anti-angiogenic treatment response that may improve the evaluation and development of new anti-angiogenic therapies.

                    1116.   Changes in Tumor Perfusion and Oxygenation Following CA4P Administration

                                Florence Colliez1, Anne-Catherine Fruytier1, Marie-Aline Neveu1, Julie Magat1, Bernard Gallez1, Bénédicte F. Jordan1

                                1Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, University of Louvain, Brussels, Belgium

 

Vascular discrupting agents (VDAs) induce tumor hypoxia within 3 hours in preclinical models. Combretastatin A4 phosphate (CA4P) is the lead compound of this agents’ class.  The present work correlates a follow-up on two tumor models of both tumor oxygenation and tumor hemodynamics after CA4P administration. Mapping of tumor oxygenation was assessed with ‘MOBILE’ (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) a non-invasive MRI method based on the changes in the relaxation properties of the tissue lipids protons whereas tumor hemodynamics (Ktrans and vp) variations were evaluated by DCE-MRI on same tumor models.

                    1117.   MRI at 7 T Correlates Therapy-Induced Alterations in T2 Heterogeneity, ADC and Tumor Volume in Ewing’s Sarcoma Xenografts

                                Parastou Foroutan1, Christopher L. Cubitt2, Jillaina L. Menth, Damon Reed3, Olya Grove1, David L. Morse1, Daniel Sullivan4, Robert J. Gillies1, Gary V. Martinez1

                                1Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, United States; 2Experimental Therapeutics Program / Translational Research Lab, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, United States; 3Experimental Therapeutics Program / Sarcoma Program, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, United States; 4Experimental Therapeutics Program, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, United States

 

In spite of the progress with targeted therapies, response rates for Ewing’s sarcoma (ES), one of the most aggressive human malignancies, still remains poor. In addition, imaging approaches assessing therapeutic response is lacking, as current indices (volume/diameter) do not accurately correlate with changes in tumor biology. Herein, profound MRI analyses were developed to evaluate imaging biomarkers for Dasatinib and Triciribine treated ES xenografts. Notably, we showed that inhibited tumor growth was presaged by elevations in ADC, ADC distribution and T2 heterogeneity. This approach accentuates the role of ADC as a quantitative imaging biomarker for response and shows promising clinical relevance in the sarcoma patient population.

                    1118.   Non-Invasive Imaging Biomarkers of Tumor Response to XL184 Therapy

                                Benjamin A. Hoff1, Jean-Christophe Brisset2, Stefanie Galbán3, Craig J. Galbán1, Brian D. Ross1

                                1Radiology, University of Michigan, Ann Arbor, MI, United States; 2New York University Langone, NY, United States; 3Radiation Oncology, University of Michigan, MI, United States

 

Clinical response criteria (RECIST 1.1) considers boney metastases measuring >10mm without soft tissue involvement as unmeasurable. The clinical need for accurate therapeutic response measures is more pressing with the introduction of targeted therapies into standard of treatment. XL184 is a novel tyrosine kinase inhibitor that exhibits activity against mainly MET and VEGFR-2.1 We evaluated DW-MRI and CT pre- and post-therapy on a mouse model of bone-metastatic prostate cancer to assess early treatment response to this therapy. The therapeutic effect of XL184 was observed via several readouts, with mean tumor ADC increasing significantly over controls by day 3 post-therapy.

 

                    1119.   Multimodality Imaging End-Points on MTOR and HSP Inhibition in Pancreatic Cancer: A Pre-Clinical PET/MRI/MRS Study

                                Justin Y. Lee1, Lora A. Wilson2, Jerri L. Choi, Kendra M. Huber3, Andrea L. Merz3, Katerina J. Kechris4, Colin D. Weekes2, Natalie J. Serkova3, 5

                                1Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; 2Department of Oncology, University of Colorado Anschutz Medical Campus, CO, United States; 3Department of Anesthesiology, University of Colorado Anschutz Medical Campus, CO, United States; 4Department of Biostatics and Informatics, University of Colorado Anschutz Medical Campus, CO, United States; 5Department of Radiology, University of Colorado Anschutz Medical Campus, CO, United States

 

There is an urgent need to develop novel signal transduction pathway inhibitor strategies to treat pancreatic cancer. This project utilizes a combination of the mTOR inhibitor Everolimus and the HSP-90 inhibitor Ganetepsib with the goal of establishing metabolic (FDG-PET and 1H-MRS), morphological (DWI), and anatomical (MRI) end-points to monitor response in mouse pancreatic adenocarcinoma xenografts. Combination treatment resulted in decreased tumor growth, cellularity, and metabolic activity. Our results provide the first evidence of proliferation and metabolic response by functional multiparametric imaging and FDG-PET, DWI and 1H-MRS and identify them as potential biomarkers in clinical trials.

                    1120.   Investigating MRI Biomarkers as Indicators of Early Treatment Response in a Triple Negative Model of Breast Cancer

                                Stephanie L. Barnes1, 2, Jennifer G. Whisenant1, 2, J. Oliver McIntyre1, 3, Thomas E. Yankeelov1, 2

                                1Vanderbilt University Institute of Imaging Sciences, Vanderbilt University, Nashville, TN, United States; 2Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States; 3Cancer Biology, Vanderbilt University, Nashville, TN, United States

 

This work aims to assess the feasibility of diffusion weighted and dynamic contrast enhanced MRI (DW- and DCE-MRI, respectively) parameters as early (i.e., before tumor volume changes) indicators of treatment response to Abraxane in a preclinical model of triple negative breast cancer.  We found that ADC and Ktrans were significantly different from the control group in both high and low dose treatment groups on day 2, prior to any observable difference in the tumor size.  These results indicate that ADC from DW-MRI and Ktrans from DCE-MRI could serve as noninvasive, early indicators of treatment response.

                    1121.   Evaluation of Tumor Oxygenation in Response to an Indole-Based Vascular Disrupting Agent Using 19F MRI

                                Heling Zhou1, Rami R. Hallac2, Rebecca Denney1, Li Li1, Ramona Lopez1, Li Liu1, Edward E. Graves3, Mary Lynn Trawick4, Kevin G. Pinney4, Ralph P. Mason1

                                1Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Analytical Imaging and Modeling Center, Children's Medical Center , Dallas, TX, United States; 3Radiation Oncology and Radiology, Stanford University, CA, United States; 4Chemistry and Biochemistry, Baylor University, Waco, TX, United States

 

Oxi8007, a novel vascular disrupting agent, showed rapid and highly selective shutdown of tumor vasculature. In this study we explored the onset of hypoxia with FREDOM, a 19F oxygen mapping technique, to assess the pO2 changes following the administration of Oxi8007 at two different doses using an orthotopic breast cancer mouse model. Both dose groups showed rapid decrease of pO2 though with a slower rate accompanying the lower dose. PO2 maps revealed heterogeneous responses to the drug.

                    1122.   Assessment of Tumor Physiological Changes Following Hypo-Fractionated SBRT Using Multi-Parametric MRI

                                Heling Zhou1, Rebecca Denney1, Zhang Zhang2, Debabrata Saha2, Ralph P. Mason1

                                1Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States

 

Tumor hypoxia is an important biomarker related to tumor treatment response, but non-invasive measurements in vivo require further development, application and validation. We have applied oxygen enhanced MRI together with DCE MRI to explore the longitudinal effects of hypofractionated stereotactic body radiation therapy on tumor re-oxygenation and development. BOLD and TOLD responses to oxygen breathing challenge were found to decrease following radiation. Quantitative T2* also showed the same trend, whereas quantitative DCE parameters (ve and Ktrans) remained unchanged. These observations suggest potential noninvasive assessment of tumor re-oxygenation for treatment planning.

                    1123.   A Role for DCE MRI in Predicting Tumor Radiation Response

                                Rami Hallac1, 2, Heling Zhou1, Rajesh Pidikiti3, 4, Kwang Song3, 5, Strahinja Stojadinovic3, Dawen Zhao1, Vikram Kodibagkar1, 6, Peter Peschke7, Timothy Solberg3, 8, Ralph Peter Mason1

                                1Radiology, UT Southwestern, Dallas, TX, United States; 2Children's Medical Center , Dallas, TX, United States; 3Radiation Oncology, UT Southwestern, Dallas, TX, United States; 4MD Anderson, TX, United States; 5Henry Ford Hospital, MI, United States; 6Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States; 7German Cancer Center, Heidelberg, D-69120, Germany; 8Univ Pennsylvania, PA, United States

 

DCE MRI has been extensively studied and suggested to be a useful method for evaluating tumor hypoxia. Here, we evaluated correlations between quantitative DCE MRI and radiation outcome of the well characterized syngeneic Dunning prostate rat tumor R3327-AT1. Following DCE MRI, 8 tumors were irradiated with a single dose of 30 Gy, while rats breathed air or oxygen, whereas two served as non-irradiated controls. Irradiation caused significant tumor growth delay. Strong correlation was observed between tumor growth delay and ve, but there no obvious correlation with Ktrans. High temporal resolution DCE MRI could provide predictive insight into response to radiation.

                    1124.   Monitoring Response to Drug-Loaded PLGA Nanoparticles in a Mia PaCa-2 Pancreatic Tumor Model with T2 and Diffusion-Weighted MRI

                                Joseph E. Kobes1, Iman Daryaei2, Christine M. Howison1, Emmaneulle J. Meuillet3, Mark Pagel4, 5

                                1Biomedical Engineering, University of Arizona, Tucson, AZ, United States; 2Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States; 3University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States; 4Dept. of Biomedical Engineering, University of Arizona, Tucson, AZ, United States; 5Dept. of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States

 

Poly(lactic-co-glycolic) acid nanoparticles (PLGA-NP) can improve delivery of PHT-427, a promising AKT-inhibitory chemotherapeutic against pancreatic cancer.  To assess the improved therapeutic effect of PLGA-NP-loaded with PHT-427 (PLGA-PH-427), this study employed parametric maps of the Apparent Diffusion Coefficient (ADC) and T2 relaxation time to localized orthotopic pancreatic tumors, and employed ADC measurements to track tumor response to therapy, following treatment of a MiaPaCa-2 pancreatic tumor model with PHT-427 or PLGA-PHT-427.

                    1125.   MRI Guided Drug Delivery Targeting Glioma Using Inteleukin-13 Conjugated Liposome (IL-13-Liposome)

                                Xiaoli Liu1, Achuthamangalam Madhankumar1, Patti Miller2, Becky Webb1, Susan Hafenstein3, Elias Rizk1, James Connor1, Qing Yang

                                1Neurosurgery, Pennsylvania State College of Medicine, Hershey, PA, United States; 2Radiology, Pennsylvania State College of Medicine, Hershey, PA, United States; 3Medicine, Pennsylvania State College of Medicine, Hershey, PA, United States

 

There is a critical need for MRI guided drug delivery for treating glioma. We developed a liposome specifically targeting glioma using interlukin-12 receptors as the target for the tumor cells (IL-13-Liposome). Our in vivo and in vitro data demonstrated that our targeted liposome is capable of delivering anticancer drug and MRI contrast agent to the tumor cells at the same time.

                    1126.   Pharmacokinetic Modelling of Longitudinal DceMRI Scans for Assessment of Tumour Growth

                                Monica Enescu1, Amalia Cifor1, Veerle Kersemans2, Danny Allen2, Stuart Gilchrist2, John Beech2, Sean Smart2, Michael A. Chappell1, Julia A. Schnabel1

                                1Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom; 2Preclinical Imaging Group, University of Oxford, Oxford, United Kingdom

 

A new model based approach to quantify tumour growth from longitudinal dceMRI images is proposed. Subsequent time points were registered to the first  time point using a multichannel registration method based on pharmacokinetic parameter maps. This method was shown to successfully recover tumour growth, on data where the tumour change is small and gradual. We have also investigated whether pharmacokinetic parameters at the first time point can act as a predictor of localized tumour growth.

                    1127.   Towards MRI-Based Measurement of Tissue Oxygen Content

                                Scott C. Beeman1, John A. Engelbach1, Joseph J.H. Ackerman, 12, Joel R. Garbow1

                                1Department of Radiology, Washington University in Saint Louis, Saint Louis, MO, United States; 2Department of Chemistry, Washington University in Saint Louis, Saint Louis, MO, United States

 

We, and others, are pursuing a technique to measure tissue oxygenation that takes advantage of the paramagnetic property of molecular oxygen, as found dissolved in tissue. Herein, we present a R1-based breathing gas challenge technique that can distinguish radiation damage from tumor - a distinction which has been difficult to make using other methods. We further show that the R1 of brain parenchyma can be measured by isolating the R1 of bulk water and suppressing flow contributions, and that breathing of carbogen gas has a direct impact on the R1 of brain parenchyma.

                    1128.   Monitoring Tumor Response to the Direct or Indirect Targeting of Choline

                                Lionel Mignion1, Pierre Danhier1, Paolo E. Porporato2, Julie Magat1, Pierre Sonveaux2, Vincent Gregoire3, Bernard Gallez1, Benedicte F. Jordan1

                                1Biomedical Magnetic Resonance Unit, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium; 2Pole of pharmacology, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium; 3Pole of Molecular Imaging, Radiotherapy and Oncology, Université Catholique de Louvain, Brussels, Belgium

 

The aim of the current study is to assess response to the modulation of the choline pathway, that is known to be involved in oncogenesis, by using specific choline kinase and transporters inhibitors and shRNA of choline kinase. In this work we proposed a combination of choline spectroscopy and diffusion markers to predict the tumor evolution after treatment. Using these combined markers we can assess the actual inhibition of the target in vivo and assess early tumor response non invasively, in order to avoid drug resistance  with the ultimate goal of improving therapy individualization.

                    1129.   Toward Distinguishing Radiation Effects from Tumor Regrowth in an Irradiated Glioma Model

                                Carlos J. Perez-Torres1, John A. Engelbach1, Jeremy Cates2, Dinesh K. Thotala2, Robert E. Drzymala2, Joseph JH Ackerman1, 3, Joel R. Garbow1

                                1Department of Radiology, Washington University, Saint Louis, MO, United States; 2Department of Radiation Oncology, Washington University, Saint Louis, MO, United States; 3Department of Chemistry, Washington University, Saint Louis, MO, United States

 

A major unmet challenge in the treatment of brain tumors is non-invasively differentiating recurrent tumor from delayed radiation injury. Our work focused on the difference in cellularity between tumor and radiation injury via Diffusion Weighted Imaging (DWI) and Magnetization Transfer Contrast (MTC) MRI. Our results in preclinical rodent models suggest that DWI may help discriminate between tumor and radiation effects while MTC, though sensitive  , is mostly incapable of differentiating between tumor and radiation effects.

                    1130.   Adaptive Therapy: A Novel Cancer Treatment Regimen Using MRI.

                                Pedro M. Enriquez-Navas1, Tuhin Das1, Yoonseok Kam1, Parastou Foruotan1, Gary Martinez1, Robert J. Gillies1, Robert A. Gatenby2

                                1Cancer Imaging and Metabolism, Moffitt Cancer Center, Tampa, FL, United States; 2Radiology, Moffitt Cancer Center, Tampa, FL, United States

 

Cancer is treated with the highest possible dose of drug, depending on toxicity, to achieve the maximum drug effect. However, this is a flawed approach because of the evolutionary dynamics that depend on the variable fitness across the tumor. Thus, the treatment scheduling is suboptimal.

Adaptive therapy (AT) is a novel cancer therapy. The dose is dependent on the tumor status. The key point is that AT has been demonstrated to promote the growth of chemosensitive tumor cells at the expense of chemoresistant ones. With the focus on translation, we are applying MRI tools to fine tune AT in vivo.

 

                    1131.   pH-Sensitive Nanoparticle for Delivery of Lonidamine to Triple-Negative Breast Cancer: A Preliminary 31P MRS Study

                                Kavindra Nath1, Hoon Choi1, David S. Nelson1, Daniel F. Heitjan1, Dennis B. Leeper2, Jerry D. Glickson1, I-Wei Chen1, Rong Zhou1

                                1University of Pennsylvania, Philadelphia, PA, United States; 2Thomas Jefferson University, Philadelphia, PA, United States

 

To exploit the slightly acidic extracellular pH environment of cancer in comparison with normal tissue, we have made ultra pH-responsive peptide nanoparticles to encapsulate lonidamine (LND), an antineoplastic agent, for intravenous administration. Once at tumor site (pHe = 6.9), the nanoparticles melt, releasing LND molecules that diffuse to surrounding cancer cells. In normal tissues (pHe &#8805; 7.2), however, LND will not be released as the nanoparticles remain stable. Our results show that pH-responsive nanoparticles efficiently solubilize LND for i.v. injections and substantially increase the tumor bioavailability of LND.

 

                    1132.   Chemotherapy Resistant, Dormant Glioblastoma Cells Exhibit High Rates of Oxidative Metabolism

                                Tomoyuki Mashimo1, Kumar Pichumani2, Koji Sagiyama2, Vamsidhara Vemireddy1, Shyam Sirasanagandla1, Suraj Nannepaga1, Kimmo Hatanpaa3, Masaya Takahashi2, Ralph DeBeraridinis4, Elizabeth Maher1, Craig Malloy2, Robert Bachoo1

                                1Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX, United States; 2Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States; 3Pathology, UT Southwestern Medical Center, Dallas, TX, United States; 4Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, TX, United States

 

Chemotherapy resistant brain tumor (GBM) cells posses high rates oxidative metabolism

                    1133.   Gallium Maltolate Inhibits Angiogenesis in Brain Tumor Xenograft Model

                                Kimberly R. Pechman1, Andrew Lozen2, Christopher R. Chitambar3, Kathleen M. Schmainda4

                                1Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; 2Neurosurgery, Medical College of Wisconsin, Milwaukee, WI , United States; 3Medicine, Medical College of Wisconsin, Milwaukee, WI, United States; 4Radiology & Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

 

Malignant brain tumors are difficult to treat and patient survival is dismal. MRI measures of enhancing tumor volume have proven unreliable since decreases in enhancement may be independent of biologic effect. The purpose of this study was to investigate a novel therapy, gallium maltolate, for brain tumors using the U87 xenograft model. In this study we used steady state and DSC-MRI to measure tumor blood volume and flow.   The studies, demonstrate that the novel gallium maltolate therapy inhibits brain tumor angiogenesis.

                    1134.   Feasibility of MR-Guided Needle-Directed Intratumoral HoMS Delivery for Localized Radiation Therapy in a Large Tumor-Model

                                Bo Sybren van Leeuwen1, Sebastiaan Alexander van Nimwegen2, Frank Zijlstra3, Chris Oerlemans3, Jolle Kirpensteijn2, Johannes Franciscus Nijsen, Peter Roland Seevinck3

                                1Dept. of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine Utrecht University , Utrecht, Netherlands; 2Dept. of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine Utrecht University, Utrecht, Netherlands; 3Image Sciences Institute, Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands

 

In this study, we demonstrated the feasibility of MR-guided needle-directed intratumoral 165HoMS delivery in a large tumor model. MRI facilitated tumor visualization, entry point determination and needle trajectory planning. The presented approach enabled dynamic monitoring of the needle insertion and needle tip positioning in the tumor, allowing intraprocedural optimization of HoMS delivery. coRASOR reconstruction was demonstrated to improve needle visualization by generating positive contrast, causing the titanium needles to be easily identified with high spatial and temporal resolution when applied prospectively. Future work should also aim at facilitating intraprocedural dosimetry to enable optimization of the number of injection sites and the amount of HoMS to be delivered to eventually provide a favorable dose distribution on the tumor, while sparing the healthy tissue.

           

                    1135.   Nitroxoline Induces Apoptosis and Slows Glioma Growth In Vivo

                                Jelena Lazovic1, Lea Guo1, Jonathan Nakashima2, Whitney Pope

                                1Radiology, University of California, Los Angeles, CA, United States; 2Molecular and Medical Pharmacology, University of California, Los Angeles, CA, United States

 

Chemotherapeutic potential of FDA approved small molecule nitroxoline was evaluated in preclinical Pten/Kras glioma mouse model. 

  The glioma volume before and after nitroxoline therapy was measured using T2-weighted MR images.  Apparent diffusion coefficient and T2-values were quantified in order to determine if they can be used to predict treatment response.  A significant reduction in glioma growth at 7 and 14 days was accompanied with significant increase in ADC values, while there was no change in T2-values.  Histological examination and TUNEL staining revealed significantly more TUNEL-labeled cells in nitroxoline treated mice, implicating nitroxoline is potent at inducing apoptosis in this model.

 

                    1136.   Selective Acidification and De-Energization of A2780 Ovarian Cancer Xenografts Using Lonidamine: A Preliminary 1H and 31P MRS Study

                                Kavindra Nath1, Ting Liu1, David S. Nelson1, Daniel F. Heitjan1, Dennis B. Leeper2, Jerry D. Glickson1, I-Wei Chen1, Rong Zhou1

                                1University of Pennsylvania, Philadelphia, PA, United States; 2Thomas Jefferson University, Philadelphia, PA, United States

 

In vivo 31P Magnetic Resonance Spectroscopy demonstrates that A2780 ovarian cancer xenografts treated with the monocarboxylate transporter-1 (MCT-1) inhibitor, lonidamine (LND), exhibits a sustained and tumor-selective decrease in delta  pHi and pHe of 0.56 ± 0.10 (p < 0.05) and 0.34 ± 0.23 (p = 0.05) respectively. Tumor bioenergetics (&#946;NTP/Pi) decreased by 70.0 ± 22% (p < 0.05) and integrated intensities of the steady-state tumor lactate were increased after 40 min. (p < 0.05) relative to the baseline level following LND administration. The decline of pHi and bioenergetics could be critical parameters for chemo- and thermo-sensitization of ovarian cancers.

                    1137.   Serial Imaging of Physiological and Metabolic Changes in Response to Radiotherapy with Tumor-Bearing Mice

                                Masayuki Matsuo1, Shingo Matsumoto1, Keita Saito1, Yoichi Takakusagi1, Douglas Morris2, Jeeva Munasinghe2, Nallathamby Devasahayam1, Sankaran Subramanian1, James Mitchell1, Murali Krishna1

                                1Radiation Biology Branch, National Institues oh Health, North Bethesda, MD, United States; 2National Institute of Neurological Disorder and Stroke, National Institues oh Health, North Bethesda, MD, United States

 

A non-invasive co-imaging system of pO2 and pyruvate metabolism was developed to visualize the correlation between tumor oxygen status and energy metabolism. SCCVII and HT29 were compared when the size of both tumors was similar. We investigated the effect of single 5 Gy irradiation on the relationship in HT29 tumors. SCCVII has significantly larger hypoxic sub-region (pO2 < 8 mmHg) than HT29. Lactate/pyruvate ratio in 0-8mmHg of 1 day after 5Gy irradiation of HT29 is higher than of non irradiation of HT29 that is explained by decreased perfusion, decreased tumor pO2, and increased extracellular acidification rate.

                    1138.   Dynamic MRS of Hyperpolarized 1-13C Pyruvate in Brain Tumor Afflicted Mice Treated with Temozolomide

                                Teresa Delgado-Goñi1, 2, Eva Monteagudo3, Miquel E. Cabañas3, Carles Arús1, 2, Silvia Lope-Piedrafita3

                                1Department de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain; 2Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Vallès, Barcelona, Spain; 3Servei de RMN, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain

 

In this study we aimed to evaluate the detection of response to temozolomide therapy in a well characterized mouse brain glioma model by hyperpolarized [1-13C] pyruvate. Quantification of time course 13C spectra showed significant differences between wildtype and untreated-glioblastoma-bearing mice in the lactate signals from 12s to 50s post-injection. However no differences were observed in lactate between untreated and treated glioblastoma-bearing mice. Nevertheless, individual Lac/Pyr ratios of treated mice seemed to have two separate patterns, one with increased ratios and the other with smaller values, which could indicate different behavior with respect to therapy response variability in the evaluated mice.

                    1139.   Preliminary Evidence of a Vascular Normalization Biomarker in Trastuzumab-Treated HER2+ Breast Cancer

                                Anna G. Sorace1, 2, Jennifer G. Whisenant1, 2, J. Oliver McIntyre, 23, Violeta M. Sanchez4, Mary E. Loveless2, Thomas E. Yankeelov1, 2

                                1Radiology, Vanderbilt University, Nashville, TN, United States; 2Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 3Cancer Biology, Vanderbilt University, Nashville, TN, United States; 4Hematology Oncology, Vanderbilt University, Nashville, TN, United States

 

We use quantitative DCE-MRI to determine sensitivity to HER2+ targeted breast cancer treatments early in the course of therapy. Preclinical studies utilizing mice with HER2+ (sensitive or resistant) tumors were treated with trastuzumab or saline. DCE-MRI was longitudinally tracked from baseline to day 4. DCE-MRI parameter, Ktrans, revealed significant increases post treatment in the HER2+ sensitive, treated tumors compared to their control counterparts, untreated and HER2+ resistant treated, therefore suggesting vessel normalization. Paralleled histological parameter, microvessel density, also revealed significant increases. Imaging biomarkers have potential as a noninvasive tool to discriminate responders from nonresponders early during the course of therapy.

                    1140.   Lonidamine Sensitizes Human Breast Cancer Xenografts to Doxorubicin Via Metabolic Modulations

                                Kavindra Nath1, Jerry D. Glickson1, David S. Nelson1, Daniel F. Heitjan1, Dennis B. Leeper2, I-Wei Chen1, Rong Zhou1

                                1University of Pennsylvania, Philadelphia, PA, United States; 2Thomas Jefferson University, Philadelphia, PA, United States

 

We demonstrate that a small molecule, lonidamine (LND), sensitizes breast cancers to the chemotherapeutic drug, Doxorubicin, via selective intracellular acidification and suppression of high energy phosphate production of the tumor. In vivo MR spectroscopy of human breast cancer xenografts show that LND treatment induces a maximal decrease of intracellular pH of 0.54 unit and depletion of  NTP/Pi by 77% accompanied by 3-fold increase of tumor lactate content. One treatment with LND (100 mg/kg, i.p.) combined with one injection of doxorubicin (12 mg/kg, i.v.) leads to a tumor growth delay of 23 days and log10 cell-kill of 1.70. These results suggest that LND potentiates chemotherapeutics by modulating cancer metabolism.

Traditional Poster

Cancer Preclinical Animal Studies

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1141.   Dynamic 3D Compressed Sensing MR of Hyperpolarized 13C Pyruvate and Urea in Prostate Cancer Models

                                Hsin-Yu Chen1, Peder E. Z. Larson2, Cornelius von Morze2, Christine Leon Swisher1, Naeim Bahrami2, Robert Bok2, John Kurhanewicz, 12, Daniel B. Vigneron, 12

                                1Graduate Program in Bioengineering, UCSF and UC Berkeley, San Francisco, CA, United States; 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States

 

Use of 3D compressed-sensing [13C]pyruvate and [13C]urea MRSI sequence and dynamic models enables, for the first time, simultaneous evaluation of metabolic and perfusion parameters kpl and ktrans in a preclinical prostate tumor model. We demonstrates increases in both pyruvate-to-lactate conversion rate and perfusion/permeability in prostate tumor versus normal tissue. This approach shows great potential for the quantitative assessment of prostate cancer aggressiveness and also treatment response.

                    1142.   Simultaneous Hyperpolarized 13C Pyruvate and Urea Perfusion Parameterizations in Cancer

                                Naeim Bahrami1, Cornelius Von Morze1, Christine Leon1, Daniel B. Vigneron1, Peder E.Z. Larson1

                                1Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States

 

In cancerous tissue there is both existing vasculature and neovascularization as different kinds of lesions surpass the normal blood supply, including small circulation disturbance in some of the abnormal vessels.

The variation of pyruvate perfusion and urea perfusion can be observed for the healthy and cancerous tissues.

The urea perfusion is primarily representing the vasculature delivery in each specific tissue and it stays in the vessels, while the pyruvate perfusion,which is the accumulation of all source and derived metabolites related to the pyruvate including pyruvate,lactate and alanine, can also be a marker for vascular delivery but also includes tissue uptake.

 

                    1143.   19F MRI of Colitis-Associated Colon Cancer (CACC) in a Murine Model of Inflammatory Bowel Disease

                                Deepak K. Kadayakkara1, 2, Soo Hyun Shin3, 4, Jeff W. M. Bulte2, 3

                                1Dept. of Oncology, The Johns Hopkins School of Medicine, Baltimore, MD, United States; 2Dept. of Radiology and Radiological Science, The Johns Hopkins School of Medicine, Baltimore, MD, United States; 3Cellular Imaging Section, Institute for Cell Engineering, The Johns Hopkins School of Medicine, Baltimore, MD, United States; 4Dept. of Biomedical Engineering, The Johns Hopkins School of Medicine, Baltimore, MD, United States

 

Invasive colonoscopy has showed that the severity of colon inflammation correlates with the development of colitis-associated colon cancer (CACC). We applied 19F MRI to non-invasively image inflammation and premalignant tumor formation. Mice were treated with azoxymethane and dextran sodium sulfate to induce CACC. The course of inflammation and tumor development was determined with MRI following injection of perfluorocarbons that are taken up by macrophages. 19F signals were detected from the colon wall, with tumors arising from the same anatomical sites. Thus, 19F MRI appears useful to further characterize the relationship between bowel inflammation and risk of CACC.

                    1144.   Combined Magnetic Resonance Spectroscopy and Mass Spectrometry Imaging of Breast Tumor Hypoxia

                                Asif Rizwan1, Lu Jiang1, Nadine Mascini2, Vadappuram P. Chacko1, Menglin Cheng1, Venu Raman1, 3, Zaver M. Bhujwalla1, 3, Ron Heeren2, Kristine Glunde1, 3

                                1Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2FOM Institute AMOLF, Amsterdam, Netherlands; 3The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

 

Our goal is to identify a probe for imaging hypoxia in breast cancer models, which can be detected in vivo by magnetic resonance spectroscopy (MRS) and ex vivo by mass spectrometry imaging (MSI). We tested hypoxyprobe F6, which was intravenously injected in breast tumor xenograft bearing mice, and detected in vivo using 19F MRS. Following sacrifice of mice and tumor removal, the hypoxia probes F6 and pimonidazole were imaged for the first time ex vivo by matrix-assisted laser desorption ionization (MALDI) MSI. Hypoxyprobe F6 has the potential to be a multimodality imaging reporter for hypoxia detection by MRS and MSI.

                    1145.   Neurochemical Profile Differentiation of Glioma Induced by Cancer Stem Cells Expressing WIF1: A 1H-MRS Longitudinal Study at 14.1T

                                Marta Lai1, Cristina Cudalbu2, Bernard Lanz1, 3, Irene Vassallo4, Marie-France Hamou4, Monika Hegi4, Rolf Gruetter2, 5

                                1Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Centre d’Imagerie Biomedicale, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Department of Radiology, University of Lausanne, Lausanne, Switzerland; 4Laboratory of Brain Tumor Biology and Genetics, Department of Neurosurgery, Lausanne University Hospital, Lausanne, Switzerland; 5Departments of Radiology, University of Lausanne and Geneva, Switzerland

 

WIF1 gene has been recently identified as a tumor suppressor gene in glioblastoma. Human glioma stem cells have been genetically modified for the expression of the WIF1 gene, they were injected intracranially in NUDE mice for 1H MRS analysis and compared with a group of mice injected with the analogue cell line without modifications. Quantification of 1H MRS spectra acquired longitudinally throughout the tumor development showed distinct metabolic features in the two groups of mice which correlate with a less aggressive phenotype for glioma stem cells expressing WIF1.

                    1146.   Localized, Non-Invasive In Vivo Measurement of Enzymatic Activity Using MAD-STEAM HP 13C MRSI

                                Christine Leon Swisher1, 2, Peder E.Z. Larson1, 2, Robert A. Bok1, Justin Delos Santos1, Romelyn Delos Santos1, Hsin-Yu Chen1, 2, Adam B. Kerr3, John M. Pauly3, Sarah J. Nelson1, 2, John Kurhanewicz1, 2, Daniel B. Vigneron1, 2

                                1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, United States; 3Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, CA, United States

 

MAD-STEAM MRSI provides a simple and robust method for parametric mapping with increased specificity to cellular exchange without concomitant signals from arterial input or T1 relaxation. We show that this technique correlates with enzymatic activity (R2= 0.883) and can be used to non-invasively measure enzymatic activity in vivo and identify regions with high enzymatic activity (p-value = 0.003). In the field of oncology in particular, this new technique has great biomedical and clinical significance, as it could be used to better identify particularly aggressive regions within tumors, target image-guided biopsies, monitor cancer progression, and follow response to therapy.

                    1147.   Effect of C-Myc Expression on Cellular-Interstitial Water Exchange Kinetics: Conditional Transgenic Mouse Breast Cancer Model

                                Ramesh Paudyal1, Sergey Magnitsky2, Steve Pickup3, Lewis A. Chodosh4, Charles Springer5, Jerry D. Glickson3

                                1Yerkes Imaging Center, Yerkes Regional Primate Research Center, Emory University, Atlanta, GA, United States; 2Radiology, USCF, CA, United States; 3Radiology, University of Pennsylvania, Philadelphia, PA, United States; 4Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA, United States; 5Advanced Imaging Research Center, Oregon Health & Science University, OR, United States

 

In this study, we evaluate the effect on cellular-interstitial water exchange in Transgenic MTB/TOM mice DCE-MRI data, which conditionally express the human oncogene c-myc in mammary glands in response to doxycycline (dox) treatment, using Shutter Speed Model (SSM). The data were measured with dox and 4 days after withdrawal of dox. Herein, we observed a significant decrease in Ktrans and ti after a removal of dox. Changes in Ktrans and ti might serve as surrogate biomarkers in breast cancer study.

                    1148.   Correlation Between in Vivo and ex Vivo MRI of Mouse Mammary Glands with Regards to Apparent Diffusion Coefficient and T2 Values

                                Xiaobing Fan1, Kay Macleod2, Devkumar Mustafi1, Suzanne D. Conzen3, Erica Markiewicz1, Marta Zamora1, Jim Vosicky1, Jeffrey Mueller4, Gregory S. Karczmar1

                                1Department of Radiology, The University of Chicago, Chicago, IL, United States; 2Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, United States; 3Medicine, Hematology/Oncology, The University of Chicago, Chicago, Chicago, IL, United States; 4Department of Pathology, The University of Chicago, Chicago, IL, United States

 

High resolution ex vivo imaging can improve understanding of cancer and guide evaluation of surgical specimens.  The rationale for ex vivo MRI is strengthened if there is a strong correlation between ex vivo and in vivo images.  Here we evaluate MRI at 9.4 Tesla of a mouse model (n = 7) of breast cancer.  For ex vivo experiments, excised skin and glands were wrapped around a sponge to maintain the in vivo spatial configuration.  There was a strong correlation (0.73 < r < 0.86, p < 0.0001) between the in vivo and ex vivo ADC’s and T2’s.

                    1149.   Dual Biomarker CEST-MRI Evaluates Tumor pH and Vascular Perfusion in an Orthotopic Ovarian Cancer Model

                                Liu Qi Chen1, Kyle Mitchell Jones2, Christine Howison2, Setsuko K. Chambers3, Amanda Baker4, Mark Pagel5

                                1Chemistry, University of Arizona, Tucson, AZ, United States; 2Biomedical Engineering, University of Arizona, Tucson, AZ, United States; 3Obstetrics and gynecology, University of Arizona, AZ, United States; 4Pharmacology, University of Arizona, Tucson, AZ, United States; 5Biomedical Engineering and Chemistry, University of Arizona, Tucson, AZ, United States

 

Extracellular pH (pHe) is a hallmark for tumor microenvironment. AcidoCEST MRI is a noninvasive MRI method that can measure pHe to assess tumor acidosis. This method allows for a pixel by pixel pH analysis that can accurately determine spatial heterogeneity of the tumor as well as contrast agent uptake.  In this study, acidoCEST MRI was used to assess an SKOV3 ovarian tumor model. Our results showed that the tumor model was mildly acidic, with an average pH of 6.88.  Additionally, tumor acidosis and lower perfusion were correlated with larger ovarian tumors.

 

 

 

 

                    1150.   Feasibility of Amide Proton Transfer Imaging of Rodent Glioblastoma Model at 3T Clinical Scanner

                                Jinsuh Kim1, Phillip Zhe Sun2

                                1Radiology, University of Iowa, Iowa City, IA, United States; 2Radiology, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States

 

In this work, a practical amide proton transfer (APT) imaging method for small animal brain at 3T clinical scanner was developed using a multi-shot sequence with k-space trajectory of 2D interleaved variable-density (VD) spiral-out. This method was applied on 4 orthotropic GBM xenograft models in immune-deficient rats. This study demonstrated elevated APT effect within the tumors with measured APT ratio ranging from 3.40 to 5.28% (4.2±0.83; mean±S.D.) consistent with prior studies. Efficient use of gradient hardware in VD spiral sequence allowed small field-of-view acquisition while maintaining reasonable signal-to-noise ratio for small animal brain scan at clinical 3T scanner.

                    1151.   Redox State Imaging in a Mouse Model of Aggressive Prostate Cancer

                                Alan B. McMillan1, Bilal Bin-Hafeez2, Ajit K. Verma2, Weixiong Zhong3, Terry D. Oberley3, Luksana Chaiswing3

                                1Radiology, University of Wisconsin, Madison, WI, United States; 2Human Oncology, University of Wisconsin, Madison, WI, United States; 3Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, United States

 

The use of stable free radical contrast agents (nitroxides) has been demonstrated in MRI and electron paramagnetic resonance imaging (EPRI). The agent 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) is a superoxide dismutase mimetic that also shortens longitudinal relaxation time (T1). After intravenous administration, the temporal rate of T1-weighted signal normalization is increased in tissues that are more oxidizing. The redox status (balance of oxidizing and reducing species) is important in cancer progression, where cancer aggressiveness is related to increased tissue oxidation. The purpose of this work is to investigate the feasibility of measuring TEMPOL signal dynamics in mouse models of prostate cancer.

                    1152.   Direct Imaging of Tumor Cellularity Using Restriction Spectrum Imaging in a Xenograft Mouse GBM Model

                                Tuva Hope1, 2, Joshua Kuperman3, Anders Dale3, Nate White3

                                1Medical Imaging Lab, NTNU, Trondheim, Norway; 2Intervention Center, Oslo University Hospital, Oslo, Norway; 3Multimodal Imaging Lab - UCSD, San Diego, United States

 

Using a GBM xenograft mouse model we demonstrate how restricted water signal, as measured with constant b-value, multi diffusion time diffusion experiment, provides a novel contrast mechanism for identifying cancer cells in vivo.

                    1153.   1 Tesla Bench-Top MRI of a Mouse Model of Colorectal Carcinoma Metastasis in the Liver: Comparison with 9.4 Tesla

                                Rajiv Ramasawmy*1, 2, Thomas Roberts*1, 3, Bernard Siow1, Sean Peter Johnson1, 2, Jack Anthony Wells1, Alan Bainbridge4, Rosamund Barbara Pedley2, Mark Francis Lythgoe†1, Simon Walker-Samuel†1

                                1Centre for Advanced Biomedical Imaging, University College London, London, Greater London, United Kingdom; 2Cancer Institute, University College London, London, Greater London, United Kingdom; 3Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, Greater London, United Kingdom; 4Department of Medical Physics, University College London, London, Greater London, United Kingdom

 

Low-field pre-clinical MRI scanners offer economical imaging of small animal models of cancer, although whether they provide sufficient signal-to-noise for the detection of tumours within reasonable imaging times is currently unknown. In this study, tumour and liver volumes were measured in a mouse model of liver metastasis using a 1T bench-top MRI system and a 9.4T scanner. Volumetric comparison was performed, alongside signal-to-noise characterisation and contrast assessment between tumour and liver. T1 and T2 mapping is also reported. Volumetric analysis of livers and tumours showed good correspondence, suggesting that bench-top MRI scanners potentially offer a cost-effective platform for accurately monitoring deep-seated tumour models and liver diseases.

                    1154.   In-Vitro Detection of Apoptosis Using Oscillating and Pulsed Gradient Diffusion Magnetic Resonance Imaging

                                Sharon Portnoy1, Nicole D. Fichtner2, Claudia Dziegielewski1, Martin P. Stanisz1, Greg J. Stanisz1, 2

                                1Sunnybrook Research Institute, Toronto, Ontario, Canada; 2Department of Medical Biophysics, University of Toronto, Ontario, Canada

 

A wide range of diffusion experiments and a simple model of diffusion in tissues were used to probe the microstructural effects of apoptosis. Experiments were conducted on acute myeloid leukemia (AML) cell pellets, where apoptosis was induced by

treatment with the chemotherapeutic

agent, cisplatin. Seventy-two hours

following treatment pulsed (PGSE) and

oscillating (OGSE) gradient diffusion

measurements were performed to assess

effects across a broad range of structural scales. The presence of apoptosis,which was confirmed by histology, significantly altered diffusion properties.

 

                    1155.   A Feasibility Study of Diffusion MRI for Early Detection of Xenograft Models in Mice.

                                Paola Porcari1, 2, Monika E. Hegi3, Hongxia Lei1, Marie-France Hamou3, Irene Vassallo3, Silvia Capuani4, 5, Rolf Gruetter1, 6, Vladimir Mlynarik1, 7

                                1Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom; 3Clinical Neurosciences, Laboratory of Brain Tumor Biology and Genetics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; 4CNR-IPCF UOS Roma Sapienza, Physics Department, Sapienza University of Rome, Rome, Italy; 5Center for Life Nanoscience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy; 6Departments of Radiology, Universities of Lausanne and Geneva, Switzerland; 7High Field MR Center, Medical University of Vienna, Vienna, Austria

 

In this study, high sensitivity and specificity of diffusion MRI methods for early detection of slow growing and highly infiltrative tumours, otherwise not visible in conventional T2-weighted images, haves been demonstrated. In contrast to conventional MRI, tumours grown as human glioma sphere xenografts in mice were identified and investigated in the early stages, and confirmed by proton MR spectroscopy and immunohistochemistry. Differences in diffusion properties of each xenograft highlighted diverse tumour microstructures which were notably reflected by histology.

                    1156.   Identification of Early Stage Glioblastoma Multiform in Rats by Multi-Parametric MR Imaging Techniques: Preliminary Results

                                Xu Han1, 2, Hua Guo2, Le He2, Xiaodong Ma2, Tingting Ha3, Kai Wang4, Yanfeng Xu5, Jianming Cai1, Xihai Zhao2

                                1Department of Radiology, Chinese PLA general hospital, Beijing, China; 2Center for Biomedical Imaging Research & Department of Biomedical Engineering, Tsinghua University, Beijing, China; 3Department of Radiology, Tiantan hospital, Capital Medical University, Beijing, China; 4Imaging Center of Neuroscience, Tiantan Hospital, Capital Medical University, Beijing, China; 5Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences, Beijing, China

 

In this study, the preliminary results indicate that the multi-parametric MR imaging technique is feasible to identify the GBM in rats at early stage. Compared to the traditional imaging sequences, each sequence of our multi-parametric imaging protocol, such as spiral DWI, VDS-DWI, DCE-MRI and CE-T1W, enables discrimination of the early stage GBM from post-injury brain edema. For VDS-DWI, the increase of SNR and removal of distortion can be also obtained in GBM animal model in our study. The multi-parametric imaging techniques might be an alternative imaging approach to detect lesions no matter in brain or other organs at clinically.

                    1157.   Longitudinal Generalized Q-Sampling MRI Evaluation in Rabbit Brain After Cerebral Hemisphere Radiation Exposure

                                Chao-Yu Shen1, 2, Fang-Yu Nien1, Zhen-Hui Li1, Yeu-Sheng Tyan1, 2, Jun-Cheng Weng1, 2

                                1School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan; 2Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan

 

Radiation therapy is widely used for the treatment of both primary and metastatic brain tumors and can lead to cellular, vascular and axonal injury and further behavioral deficits. Imaging assessment of the brain damage caused by radiation therapy is very important for determining patient prognoses. Previously we used diffusion tensor imaging (DTI) and T2-weighted imaging (T2WI) to evaluate post-irradiation brain injury. To improve evaluation of the neuro-toxic adverse effects of irradiation treatment in both gray and white matter structures, in this study we longitudinally evaluated the changes in various brain compartments on a clinical MR scanner by using generalized q-sampling imaging (GQI) indices mappings, generalized fractional anisotropy (GFA), quantitative anisotropy (QA) and isotropic value (ISO) of the orientation distribution function (ODF), for single sub-lethal high dose (30 Gy) cerebral hemisphere exposure radiation-induced brain injury on adult rabbit model.

 

                    1158.   Exploring the Biomechanical Properties of Brain Malignancies and Their Pathological Determinants with Magnetic Resonance Elastography

                                Jin Li1, Yann Jamin1, Jessica K.R. Boult1, Philippe Garteiser2, Jose L. Ulloa3, Sergey Popov4, 5, Craig Cummings1, Gary Box5, Suzanne A. Eccles5, Chris Jones4, 5, John C. Waterton3, Jeffrey C. Bamber1, Ralph Sinkus2, 6, Simon P. Robinson1

                                1Division of Radiotherapy & Imaging, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 2INSERM U773, CRB3, Centre de Recherches Biomédicales Bichat-Beaujon, France; 3Personalised Healthcare and Biomarkers, AstraZeneca, Macclesfield, Cheshire, United Kingdom; 4Division of Molecular Pathology, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 5Division of Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 6BHF Centre of Excellence, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom

 

Recently MRE revealed that tumours derived from human breast adenocarcinoma MDA-MB-231, rat Glioma RG2 or human gioblastoma U87-MG cells were softer than healthy brain tissue, with MDA-MB-231 significantly softer and less viscous than the other two models. We investigated the cellular density, microvessel density, myelin content and collagen content in these models, and showed that between the tumours, in MDA-MB-231 tumours, cell density and microvessel density were significantly lower than the other two models, positive correlated with MRE-derived elasticity and viscosity. Meanwhile, the lack of anisotropic structure of intracranial tumours may underpin their relative softness.

                    1159.   Is the Reaction-Diffusion Equation an Accurate Model of C6 Glioma Growth?

                                David A. Hormuth, II1, 2, Jared A. Weis2, Thomas E. Yankeelov2

                                1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States; 2Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States

 

The reaction-diffusion equation is a common model used to describe tumor growth. Quantitative imaging measurements may be used to drive this model. Using simulated tumor growths and experimentally measured tumor growths, we determined the acquisition strategies necessary to allow for accurate estimate of model parameters.  Additionally, the accuracy of this model in predicting in vivo tumor growth is tested. The accuracy of predicted and observed growths are compared between the simulated and experimental datasets.

                    1160.   Multiparametric Characterization of the Sex Differences in a High-Grade Glioma Rat Model by In Vivo Magnetic Resonance and Post-Mortem Analysis.

                                Rocio Perez-Carro1, Omar Cauli2, Pilar Lopez-Larrubia1

                                1Department of Experimental models of human diseases, Instituto de Investigaciones Biomédicas, CSIC-UAM, Madrid, Spain; 2Department of Nursing, University of Valencia, Valencia, Spain

 

Despite there is a clear predominance in cerebral tumors in male, gender differences are not usually considered either in the behavioural characterization or new therapies development in brain oncology. In the present work we used an animal model of high-grade glioma to assess in vivo and ex vivo the gender dependence of MR and biological parameters. Glioma bearing female rats showed more extended necrosis in tumors than males, while the latters present higher disruption of the blood brain barrier. We indicate the ability of using MR surrogate markers to signal and track the gender dependence in brain tumorigenesis.

                    1161.   Tracking Tissue Oxygenation Status and Response Using Diffusion-Weighted Functional MRI

ISMRM_MagnaLogo.jpg                                 Zhongwei Zhang1, Rami R. Hallac1, Qing Yuan1, Peter Peschke2, Ralph P. Mason1

                                1Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center, Heidelberg, Germany

 

The diffusion-sensitized fMRI (DfMRI) has the potential to provide noninvasive measurements of tissue oxygenation using oxygen as an endogenous paramagnetic contrast agent, in this study, we compared DfMRI response with BOLD, TOLD responses to gas breathing challenge under different baseline pO2 level. The feasibility of DfMRI for tracking tissue oxygenation status was evaluated. Our study showed that DfMRI is a powerful tool to tracking tissue oxygenation status and it can also provide the extent of response when combining baseline pO2 measurement.

                    1162.   On Conductivity, Permittivity, Apparent Diffusion Coefficients and Their Use as Cancer Markers at MRI Frequencies

                                Ileana Hancu1, Jeanette Roberts1, Seung-Kyun Lee1, Robert Lenkinski2, Selaka Bulumulla1

                                1GE Global Research Center, Niskayuna, NY, United States; 2UT Southwestern Medical Center, TX, United States

 

Experiments using an impedance analyzer/dielectric probe were performed in two rat cancer models to validate the frequency dependant differences in tissue electrical properties (TEP's) between cancer and normal tissues. Correlations between conductivity and apparent diffusion coefficient (ADC) were also investigated. While it was found that limited differences (5-30%) exist between the TEP's of cancer and normal tissue, permittivity added significant discriminant power compared to ADC alone, particularly at 1.5T and 3T. If MRI based TEP measurements could be brought to ~5% accuracy/repeatability, it is suggested that 3T exams involving ADC and permittivity mapping could better discern cancer from normal tissue.

                    1163.   PEG-Masked Ferritin-Based Multifunctional Nanoparticles in Melanoma Murine Model

                                Giulia Carpinelli1, Rossella Canese1, Elisabetta Falvo2, Cristina Maria Failla3, Miriam Carbo2, Manuela Fornara4, Serena Cecchetti1, Lenka Rajsiglova5, Dmitry Stakheev5, Jiri Krizan5, Alberto Boffi2, 4, Veronica Morea2, Luca Vannucci5, Pierpaolo Ceci2

                                1Cell Biology and Neurosciences Dept, Istituto Superiore di Sanità, Rome, Italy; 2Institute of Molecular Biology and Pathology, CNR – National Research Council of Italy, Rome, Italy; 3Molecular and Cell Biology Laboratory, IDI-IRCCS, Rome, Italy; 4Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome “Sapienza”, Rome, Italy; 5Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), Prague, Czech Republic

 

Nanoparticles (NPs)  are promising agents for enhancing cancer diagnosis and treatment. Once functionalized for selective targeting of tumor expressed molecules, they can specifically deliver drugs and diagnostic molecules inside tumor cells. We evaluated the in vivo melanoma-targeting ability of a nanovector (HFt-MSH-PEG) based on human protein ferritin (HFt), functionalized with both melanoma-targeting melanoma stimulating hormone (&#945;-MSH) and stabilizing poly(ethylene glycol) molecules, with magnetite-maghemite encapsulation.  NPs showed by MRI an accumulation in primary melanoma, with high selectivity with respect to other organs, thereby proving to be suitable vectors for selective delivery of diagnostic or therapeutic agents for cutaneous melanoma.

                    1164.   A Novel Gd-Sucrose Scaffold for Oral Administration in MR-Colonography at 7 T

                                Parastou Foroutan1, Gary V. Martinez1, Valerie E. Moberg1, Suryakiran Navath2, Robert J. Gillies1, Eugene A. Mash2, David L. Morse1

                                1Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, United States; 2Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States

 

Colorectal cancer (CRC) is the second leading cause of death in the United States and although CRC prognosis relies on early-stage-disease detection, the standard screening method, colonoscopy, suffers from patient non-compliance. Magnetic resonance colonography (MR-C) is a non-invasive approach that provides excellent soft tissue contrast and 3D datasets without radiation exposure. Herein, we present the development of targeted contrast agents for pre-screening of CRC by 7 T MRI. Specifically, a non-toxic Gd-DOTA sucrose based scaffold for oral administration that can be conjugated to targeting moieties specific for CRC was developed and evaluated in phantoms as well as in vivo in xenografts.

                    1165.   Assessment of the Tumoral Microenvironment in the Development of a Glioblastoma Rat Model by In Vivo MRI and Ex Vivo HRMAS

                                Ana Amor-López1, Rocío Pérez-Carro1, Pilar López-Larrubia1

                                1Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Madrid, Spain

 

Current techniques for evaluating microvasculature and inflammatory processes linked to cancer development, do not achieve an enough spatial and functional resolution, bordering the applications both for diagnosis and therapy validation. Magnetic resonance imaging and spectroscopy approaches offer a great potential to solving these limitations. In fact, MR approaches allow determining important characteristics of tumor microenvironment as microvascular abnormalities, tumor metabolism, oxygenation level and extracellular-pH between others. This research was focussed on the identification of MR parameters that may act as in vivo surrogate markers of biological characteristic -like inflammation, edema and BBB integrity- of a glioblastoma in a rat model.

 

Traditional Poster

Bone, Tendon & Ligament

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1166.   Monte Carlo Simulation of the Effect of Fat Spatial Distribution in Trabecular Bone Marrow on the DDIF MR Signal

                                Sara Maria Sprinkhuizen1, Jerome Ackerman1, Yi-Qiao Song1, 2

                                1MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 2Schlumberger-Doll Research, Cambridge, MA, United States

 

Decay due to Diffusion in the Internal Field (DDIF) MRI measures solid trabecular bone structures. Bone marrow plays an important role in DDIF MRI: the magnetic susceptibility of marrow fat induces field gradients in the pore spaces which depend on the water-fat ratio and spatial distribution of the fat cells within the pores. In this work we assessed whether DDIF MRI technique may be used to detect bone marrow alterations and diseases. As a first step towards this goal, we simulated the effect of the spatial distribution of marrow fat cells on the DDIF MRI signal for 3 clinical cases.

                    1167.   Reproducibility of In Vivo Bound and Pore Water Imaging of Cortical Bone

                                Mary Kate Manhard1, 2, Robert Adam Horch3, 4, Daniel F. Gochberg3, 4, Jeffry S. Nyman5, Mark D. Does1, 4

                                1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States; 2Vanderbilt University Institute of Imaging Science , Vanderbilt University, Nashville, TN, United States; 3Radiology & Radiological Sciences, Vanderbilt University, Nashville, TN, United States; 4Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 5Department of Orthopaedics & Rehab, Vanderbilt University, Nashville, TN, United States

 

The previously proposed DAFP and AIR sequences were applied to in vivo clinical scans on three human subjects on the wrist and the lower leg. Bound and pore water concentration maps were obtained from the images on cortical bone of the radius and tibia. Each scan was repeated three times and the reproducibility was investigated as the inter-scan variability. Good repeatability was found (&#8776;10% standard error per ROI), verifying these methods as diagnostic tools for assessing bone quality.

                    1168.   SWIFT Positive Contrast Technique for Rat Knee Bone Imaging at 14 T

                                Lindsey Alexandra Crowe1, Nicolas Kunz2, Iris Friedli1, Azza Gramoun1, Kerstin Grosdemange1, Curtis A. Corum3, Rolf Gruetter2, Jean-Paul Vallée1

                                1Division of Radiology, Geneva University Hospitals,, Geneva, Switzerland; 2Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

 

Sweep Imaging with Fourier Transform (SWIFT) imaging at 14 T shows short T2 bone matrix structure in an antigen-induced arthritis (AIA) model in rat.  This technique is compared to gradient echo where bone structures appear dark. We explore the advantages SWIFT to assess bone matrix and erosion in the first feasibility study for small rodent joints at 14 T.

                    1169.   Investigation of Relationship Between Free-Water T1 and Age in Human Cortical Bone Employing Short-TE 1H-MRI at 1.5T

                                Atena Akbari1, 2, Shahrokh Abbasi Rad1, 2, Mohsen Shojaee Moghaddam3, Hamidreza Saligheh Rad1, 2

                                1Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran; 2Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran, Iran; 3Imaging Center, Payambaran Hospital, Tehran, Iran

 

Larger pores in human cortical bone (>30 µm) have essential role in its mechanical competence, suggesting to quantify such proton pools as a reliable measure of cortical bone porosity and thus, cortical bone quality. Signal from such pores can be reliably captured using short echo time (STE) pulse sequence with echo-time in range of 0.5-1msec. Furthermore, it is well-known that cortical bone T1-relaxivity is a function of its geometrical characteristics, suggesting subject-dependent cortical bone free water increasing with age. In this work, we investigated relationship between STE-based cortical bone T1-values and age, studies in a group of healthy volunteers at 1.5T.

                    1170.   Development of a Novel Combined Tibial and Femoral Bone Registration Method for Reliable Quantification of MR-Based Knee Joint Kinematics

                                Musa Zaid1, Drew Lansdown1, Karupppasamy Subburaj2, C. Benjamin Ma1, Richard Souza2, Xiaojuan Li2

                                1Orthopaedic Surgery, University of California San Francisco, San Francisco, CA, United States; 2Radiology and Biomedical Imaging, University of California San Francisco, CA, United States

 

Magnetic resonance imaging is an appealing approach for measuring knee kinematics. We have developed a novel combined tibial and femoral algorithm for determining MR-based knee kinematic measurements. Tibial and femoral coordinate systems were established from bone segmentations and used to establish coordinate systems to measure anterior tibial translation and internal tibial rotation. Using this novel method, knee MR images from five subjects were segmented by two independent researchers. Intra-class correlation coefficient measurements exhibited excellent inter-user and intra-user reliability of this combined registration method over a tibial only based approach.

                    1171.   Dynamic Contrast Enhanced MRI in Patellofemoral Pain Syndrome: Perfusion Quantification of Patellofemoral Joint Tissues

                                R.A. van der Heijden1, 2, D.H.J. Poot1, 3, E.E. Bron1, S. Klein1, J.A.N. Verhaar4, S.M.A. Bierma-Zeinstra2, 4, M. van Middelkoop2, G. Kotek1, E.H.G. Oei1

                                1Radiology, Erasmus Medical Center, Rotterdam, Netherlands; 2General Practice, Erasmus Medical Center, Rotterdam, Netherlands; 3Imaging Science and Technology, Delft University of Technology, Delft, Netherlands; 4Orthopedics, Erasmus Medical Center, Rotterdam, Netherlands

 

Quantitative dynamic contrast-enhanced MRI (DCE-MRI) has the potential to advance the knowledge on the pathogenesis of bone diseases,  such as PFPS, by measuring blood perfusion in bone quantitatively.  However, there is no consensus regarding optimal analysis methods and pharmacokinetic model and there is no tailored method for the patellofemoral joint yet.  We developed a tailored method for the patellofemoral joint. The results suggest that our tailored DCE-MRI protocol and post-processing tool successfully extract the dynamic contrast enhancement from the measurements, and thus can be used to study patellar blood perfusion.

                    1172.   Evaluation of Bone Quality in Calcanei of Young and Postmenopausal Women Through ADC Measurement

                                Silvia Capuani1, Rebuzzi Mauro2, Vincenzo Vinicola3, Umberto Sabatini4, Marco Bozzali5

                                1Physics Department, CNR IPCF Roma "Sapienza " University, Rome, Italy; 2Physics Department, Physics Department Sapienza University, Rome, Italy; 3Rehabilitation Hospital, IRCCS Santa Lucia Foundation, Rome, Italy; 4Radiology Department, IRCCS Santa Lucia Foundation, Rome, Italy; 5Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy

 

We have investigated water ADC changes in calcaneal cancellous bone of healthy subjects characterized by a large age range (22-69 y) and of osteopenic and osteoporotic patients at 3.0T employing DWI to quantify ADC and MRS techniques to quantify marrow fat content. ADC data from human calcanei shows the ability of diffusion measurement to obtain complementary information, compared to those provided by BMD, for investigating cancellous bone quality.

                    1173.   MR Imaging of Water and Fat in Cortical Bone: Comparison Between the SWIFT and FSE Sequences

                                Luning Wang1, Qun Zhao1

                                1Department of Physics and Astronomy, University of Georgia, Athens, GA, United States

 

Bone diseases have influenced millions of people’s lives, and MR imaging of bone is thus important and has attracted attentions of researchers and clinicians for a long time. However, bone imaging still remains a challenge for MRI, as bone, especially cortical bone, has a relatively short T2 and T2* values, which results in a fast signal decay. In this work, we aim to conduct a preliminary study to image free water stored in a sample of a swine humerus bone by using the fast spin echo (FSE) sequence and the sweep imaging using Fourier transformation (SWIFT) sequence. To get a qualitative mapping of free water distribution in the bone, MR scans were performed before and after dehydration of the sample, with fat and water saturation applied. The results demonstrate that the SWIFT sequence has an advantage on visualizing cortical bone compared with the FSE sequence, especially on visualizing bound water component in cortical bone.

 

                    1174.   Validity of Skeletal Age Assessment Based on Phalanges Using a Portable MRI

                                Yasuhiko Terada1, Shinya Inamura1, Katsumi Kose1, Ryo Miyagi2, Yasunari Fujinaga2, Hiroshi Yoshioka2

                                1Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan; 2Department of Radiological Sciences, University of California Irvine, Orange, CA, United States

 

Skeletal age can often be evaluated by assessing the maturity of 13 bones in the left hand and wrist of MR images. We have developed a portable hand scanner, which requires no shielding room, occupies only a small fraction of the space, and enables skeletal age examination in remote place. However, the available FOV size is limited and it requires several scans to image all the bones necessary for the skeletal age assessment. In this study, we limit the target bones to phalanges which can be imaged in one scan, and assess the skeletal age based on MR images of the phalanges alone.

                    1175.   Quantification of Scar Tissue Formed Around Cranial Bone Grafts, and Its Reduction by Parathyroid Hormone Therapy

                                Doron Cohn Yakubovich1, Uzi Eliav2, Michal Rivlin2, Ilan Kallai1, Gadi Pelled1, 3, Dan Gazit1, 3, Zulma Gazit1, 3, Gil Navon2

                                1Skeletal Biotech Laboratory, The Hebrew University of Jerusalem, Jerusalem, Israel; 2School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 3Department of Surgery, Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States

 

In order to examine parathyroid hormone (PTH, a bone anabolic agent) effect on scar tissue formation at calvarial bone grafts proximity, we used MRI scanning protocol, consisted of MTC and double quantum filtering to measure collagen fiber deposition in the scar-bone suture. We hypothesize that this quantitative MRI technique for evaluating collagen deposition will confirm that PTH administration decreases collagenous scar tissue formation. Indeed, in- and ex-vivo MRI revealed changes in collagen as in comparison to the control animals, enabling differentiation between new bone formation and scar tissue. Our technique will enable physicians longitudinal, non-invasive follow up of various fibrosis related conditions.

                    1176.   Co-Registration of Synchrotron Radiation-MicroCT and Micro-MRI Images: A New Method for the Complete Characterization of  Newly-Formed Bone

                                Allegra Conti1, Raffaele Sinibaldi1, Silvia Capuani2, Tonino Traini3, Gian Luca Romani1, 4, Stefania Della Penna1, 4

                                1Department of Neuroscience and Imaging, University of Chieti, Chieti, CH, Italy; 2Department of Physics, Sapienza University of Rome, Rome, RM, Italy; 3Department of Stomatology and Biotechnologies, University of Chieti, Chieti, CH, Italy; 4Institute of Advanced Biomedical Technologies, University of Chieti, Chieti, CH, Italy

 

The use of biomaterials scaffolds for bone regeneration/augmentation represents one of the most used strategies in dentistry to support prosthetic restorations. Often implant failure can be associated to the trabecular bone quality of the jaw. Here we present a new method based on the co-registration  of images of scaffold collected with the X-ray Synchtron Radiation-microCT and micro-MRI, that permit to obtain a complete and 3D characterization of scaffolds, distinguishing unambiguously different degrees of bone mineralization, multinucleate cells and blood vessels inside the bone marrow. Until now this was possible only with an histological, and so bidimensional, evaluation of the samples.

                    1177.   A Multi-Atlas and Label Fusion Approach for Patient-Specific MRI Based Skull Segmentation

                                Angel Torrado-Carvajal1, 2, Juan A. Hernandez-Tamames1, 2, Joaquin L. Herraiz2, Yigitcan Eryaman2, 3, Yves Rozenholc4, Elfar Adalsteinsson5, 6, Lawrence L. Wald3, 6, Norberto Malpica1, 2

ISMRM_MagnaLogo.jpg                                 1Dept. of Electronics, Universidad Rey Juan Carlos, Mostoles, Madrid, Spain; 2Madrid-MIT M+Vision Consortium in RLE, MIT, Cambridge, MA, United States; 3Dept. of Radiology, MGH, Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 4MAP5, CNRS UMR 8145, University Paris Descartes, Paris, France; 5Dept. of Electrical Engineering and Computer Science, MIT, Cambridge, MA, United States; 6Harvard-MIT Health Sciences and Technology, MIT, Cambridge, MA, United States

 

MRI-based bone segmentation is a challenging but important task for accurate construction of patient-specific models. We propose a method for complete skull segmentation based only on T1-weighted images of the human head. The skull is estimated using a multi-atlas (CT database) segmentation and label-fusion approach. CTs are elastically registered to the patient MRI image and thresholded. Then, the patient-specific skull is estimated using label-fusion algorithms. The method was tested in 12 healthy subjects; a radiologist evaluated and considered all the segmentations as accurate. The results may allow removing CT acquisitions in several protocols, thus decreasing patient ionization.

                    1178.   Rapid Increase of Marrow Fat Content and Decrease of Marrow Perfusion in Females Underwent Bilateral Oophorectomy: An Magnetic Resonance Based Longitudinal Study of Lumbar Vertebra

                                Yi-Xiang Wang1, David KW Yeung1, Min Deng1, Jing Yuan1, James F. Griffith1

                                1Dept Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong

 

Lumbar spine bone mineral density (BMD) with quantitative CT, marrow fat fraction (FF) and marrow perfusion using MRS and DCE MRI at the L3 vertebra in 6 females underwent hysterectomy and bilateral salpingo-oophorectomy were performed. Reduced BMD, increased marrow FF, and reduced marrow perfusion occurred in synchrony. There was a sharp decrease of 12.5±7.2% for BMD (n=6), a sharp increase of 92.2±46.3% (n=6) for FF, a sharp decrease of 23.6±3.9% for maximum enhancement (n=5), and of 45.4±7.7% for enhancement slope (n=5) during the initial 3 months post surgery. These changes occurred at a slower rate during the later follow-up period.

                    1179.   Crimp and Macrocrimp Behavior in Human Tendons with Ultra-High and High Field MRI

                                Eric Y. Chang1, Graeme M. Bydder2, Sheronda Statum2, Chantal Pauli3, 4, Merissa Olmer4, Darryl D'Lima4, Christine B. Chung1

                                1Department of Radiology, VA San Diego Healthcare System, San Diego, CA, United States; 2Department of Radiology, University of California, San Diego Medical Center, San Diego, CA, United States; 3Department of Pathology, University Hospital Zürich, Zürich, Switzerland; 4Scripps Healthcare, San Diego, CA, United States

 

Crimps is a feature of collagenous tissues that has biomechanical significance.  Utilizing ultra-high field strength MRI (11.7T), human crimp morphology is visible for the first time.  Additionally, we provide the first description of macroscopic crimps (macrocrimps) on MRI with histologic correlation, which are visible in unloaded tendon on 3T MRI.  Macrocrimps change tendon signal intensity and can potentially alter T2 measurements of tendons between loaded and unloaded states.

                    1180.   High Resolution Qualitative and Quantitative MR Imaging of the First Metatarsophalangeal Joint at 11.7T and 3.0T with Anatomic and Histologic Correlation

                                Diego A. Garcia1, Higor Grando1, Kenyu Iwasaki1, Reni Biswas1, Sheronda Statum1, Eric Y. Chang1, Graeme M. Bydder1, Christine B. Chung1

                                1Radiology, VA San Diego Healthcare System - UCSD, San Diego, CA, United States

 

The plantar plate has been identified as a major stabilizer structure of the metatarsophalangeal joint.

The purpose of the study is to provide high-resolution and quantitative MR evaluation of the first MTP joint.

Imaging of the first MTP joints were performed on 3T and 11.7T MR system of five cadaveric forefeet, and each specimen were subsequently correlated with gross and histologic anatomy.

Through high-resolution MR imaging we demonstrate that the first plantar plate is a dynamic capsuloligamentous complex. Quantitative MR of important structures of the first MTP joint may allow for earlier diagnosis, stage of injury, and therapeutic monitoring.

                    1181.   Practical Requirements for Bi-Exponential T2* Fitting in Achilles Tendon Measured by Variable Echo Time Sequence

                                Vladimir Juras1, 2, Vladimir Mlynarik1, Pavol Szomolanyi1, 2, Marek Chmelik1, Siegfried Trattnig1

                                1High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; 2Department of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

 

The results of this study provide a guide how to perform the bi-exponential T2* fitting in Achilles tendon. Besides the usual conditions used in bi-exponential fitting (such as SNR and R2 threshold), other conditions such as limits for the ratio of T2*s and T2*l obtained by fitting should also be considered for calculating reasonable T2* values. The results of this study can be extended also to other tissues (menisci, ligaments, nerves) and is method independent  (works with radial 2D and 3D-UTE, AWSOS, SPRITE).

 

                    1182.   Magnetic Resonance Imaging of Entheses of the Foot at 11.7T

                                Eric Y. Chang1, 2, Paul M. DiCamillo2, Sheronda Statum2, Christine B. Chung1, 2, Nikolaus M. Szeverenyi2, Graeme M. Bydder2

                                1Department of Radiology, VA San Diego Healthcare System, San Diego, CA, United States; 2Department of Radiology, University of California, San Diego Medical Center, San Diego, CA, United States

 

This study was performed to visualize the entheses of the foot at 3T and 11.7T utilizing 2D and 3D images. The contrast and quality of the MR images obtained have never been shown before.  These include the Achilles tendon, tibialis posterior tendon at the level of the medial malleolus and at the navicular insertion, central slip of the extensor tendon of the toes, collateral ligaments, and plantar plate.  We also demonstrate collagen fiber structure which has not previously been described, including perpendicular fibers at functional entheses.

                    1183.   T2* Value Change of Hoffa's Fat Pad with Histologic Correlation in a Rat Model of Anterior Cruciate Ligament Transection

                                Chao-Ying Wang1, Ping-Huei Tsai2, 3, Shih-Wei Chiang1, 4, Yi-Chih Hsu1, Herng-Sheng Lee5, Yue-Cune Chang6, Ming-Chung Chou7, Ming-Huang Lin8, Chien-Yuan Lin8, Hsiao-Wen Chung4, Guo-Shu Huang1

                                1Department of Radiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan; 2Imaging Research Center, Taipei Medical University, Taipei, Taiwan; 3 Department of Medical imaging, Taipei Medical University, Taipei, Taiwan; 4Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 5Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; 6Department of Mathematics, Tamkang University, Taipei, Taiwan; 7Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; 8Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan

 

In this study we use MR T2* value to compare local changes in signal intensity over time in Hoffa¡¦s fat pad in anterior cruciate ligament transection (ACLX) rats. We have applied these techniques to investigate at different time points including week 0, 4, 13, 18 in three groups (control, ACLX-shame and ACLX) after surgery. After MR imaging at week 18, we scarified the rat and undergone histological analysis. We conclude that in our study of Hoffa¡¦s fat pad, MR T2* measurement can be an useful biomarker to provide early physiological information in knee instability disease.

                    1184.   Accelerated T2* Measurements in Human Meniscus Using Projection Reconstruction with Data Sharing from Adjacent Echo

                                Ping-Huei Tsai1, 2, Hsiao-Wen Chung3, Teng-Yi Huang4, Wing P Chan5, Cheng-Yu Chen2, 6, Fong Y Tsai1

                                1Imaging Research Center, Taipei Medical University, Taipei, Taiwan; 2Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan; 3Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 4Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 5Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; 6Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan

 

Meniscus plays a critical role to maintain mechanical function of knee and is related to initiation of osteoarthritis. Although several papers have demonstrated the feasibility of using UTE sequence to target the short T2 component and derive the corresponding T2* map, it is not easy to assess the in vivo human meniscus T2* value with high resolution due to a relatively long scan time. The purpose of this study is using dual echo radial imaging sequence conjugated with undersampled projection reconstruction for accelerated meniscus T2* measurements. The present finding indicated that the use of the proposed method is able to obtain a reliable T2* value of the in vivo human meniscus.

                    1185.   The Meniscal Repair Assessment Score (MERAS) – a New MRI Scoring Tool for Evaluation of the Healing Success After Primary Meniscus Refixation – Preliminary Results

                                Beate Blutsch1, David Stelzeneder2, Silke Aldrian1, Christian Albrecht1, Patrick Platzer1, Stefan Hajdu1, Siegfried Trattnig3

                                1Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria, Austria; 2Department of Orthopaedics, Medical University of Vienna, Vienna, Austria, Austria; 3Department of Radiology, Centre of Excellence “High Field MR”, Medical University of Vienna, Vienna, Austria, Austria

 

Meniscal tears are commun injuries of the knee joint. The preservation of the meniscus is getting more and more important because of the rising number of osteoarthritis after (partial) meniscectomy.

In our study patients with a meniscal tear that was treated operatively with meniscus refixation were examined with a 7T MRI, a clinical examination and an interview six and twelve months postoperatively.

The Meniscal Repair Assessment Score (MERAS), a new MRI scoring tool for evaluation of the sutured meniscus was created, indicating good radiological outcome. Meniscal refixation offers satisfying clinical and imaging results.

 

                    1186.   Demonstration of the Root Ligaments of the Meniscus of the Knee Using a 3D UTE Cones Subtraction Sequence with and Without Contrast Enhancement

                                Michael Carl1, Jiang Du2, Nikolaus M. Szeverenyi2, Sheronda Statum2, Christine B. Chung2, Graeme M. Bydder2

                                1Global MR Applications & Workflow, General Electric, San Diego, CA, United States; 2University of California, San Diego, CA, United States

 

The root ligaments of the meniscus have an essential role in maintaining the mechanical integrity of the knee. It is possible to demonstrate tendons and ligaments as high signal structures using 3D UTE subtraction images in which short T2 tissues are highlighted. In order assess whether this was feasible and whether contrast administration would be detectable over time we studied a volunteer before and after injection of gadolinium. The root ligaments can be readily demonstrated and can be identified by their cross section appearance, internal structure and location.

                    1187.   Quantitative and Diffusion MR Imaging as a New Method to Assess Partial-Thickness Rotator Cuff Tear

                                Huan-Chu Lo1, Sheng-Tsai Hung1, Duen-Pang Kuo1, Hung-Maan Lee1

                                1Armed Forces Taoyuan  General Hospital, Taoyuan, Taiwan, Taiwan

 

Partial-thickness rotator cuff tear is usually depicted by a focal hyperintensity within a tear shown on fat-suppression T2 weighted magnetic resonance imaging (FS-T2WI). However, the hyperintensity is not always easily detected by FS-T2WI. To investigate the diagnostic performance of diffusion-weighted magnetic resonance imaging (DWI) for assessment of partial-thickness rotator cuff tears by means of lesion to muscle signal intensity ratios (L/M SIR ) as an alternative method.

                    1188.   Sodium, CEST and T2* of Human Achilles Tendon in Subjects After Ciprofloxacin Treatment

                                Vladimir Juras1, 2, Pavol Szomolanyi1, 2, Benedikt Hager1, Marek Chmelik1, Stefan Zbyn1, Jan Vosshenrich1, Siegfried Trattnig1

                                1High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; 2Department of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

 

This study showed that sodium MRI is sensitive enough to visualize macromolecular alterations which are present after ciprofloxacin treatment. Interestingly, gagCEST does not demonstrate this ability, although the p-value for BULK was only slightly above 0.05. T2* reflects mostly the water and collagen interplay, therefore, no change was observed. In conclusion, sodium MRI was proven to be a potential marker for Achilles tendinopathy  after ciprofloxacin treatment.

 

                    1189.   Evaluation of the Integration of Silk Fibroin Ligament-Like Tissue Into the Bone After ACL Reconstruction of the Sheep Model, Using 7Tesla MR Imaging.

                                Pavol Szomolanyi1, Andreas Teuschl2, 3, Martin Brix, 14, Joachim Friske1, Vladimir Juras1, Xeni Deligianni5, Oliver Bieri5, Thomas Nau6, Heinz Redl, 36, Siegfried Trattnig1

                                1Department  of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, High Field MR Centre, Vienna, Austria; 2City of Vienna Competence Team Tissue Engineering Bioreactors, University of Applied Sciences Technikum Wien, Vienna, Austria; 3The Austrian Cluster for Tissue Regeneration, Vienna, Austria; 4Department of Orthopaedics, Medical University of Vienna, Vienna, Austria; 5Department of Radiology, University of Basel Hospital, Division of Radiological Physics, Basel, Switzerland; 6Ludwig Boltzmann Institute for clinical and experimental Traumatology, Vienna, Austria

 

Most promising materials for ACL reconstruction are based on silk fibroin as scaffold material. Surprisingly, there is still a lack of knowledge on the integration of silk fibroin scaffolds into bone. Thus, the goal of this study was to evaluate the integration of silk fibroin into the bone by using MRI UTE sequence. MR analysis demonstrated that after 6 months the silk scaffolds were surrounded by soft tissue that further developed to the tight osteointegration. Our study show that UTE is the technique of choice for MR imaging of the very short T2* tissues.

                    1190.   Semi-Quantification of Fatty Degeneration Within Supraspinatus Muscle by Using 2-Point Dixon Technique at 3.0-T MRI

                                Taiki Nozaki1, 2, Junko Ochi2, Chiharu Osakabe2, Atsushi Tasaki3, Yasuhito Kaneko1, Hiroshi Yoshioka1

                                1Radiological Sciences, University of California, Irvine, Orange, CA, United States; 2Radiology, St.Luke's International Hospital, Chuo-ku, Tokyo, Japan; 3Orthopedic Surgery, St.Luke's International Hospital, Tokyo, Japan

 

In preoperative assessment of rotator cuff tear, it is very important to evaluate the degree of fatty degeneration of the rotator cuff muscles for deciding the indication of operation, and predicting the clinical functional outcome. However, in clinical practice qualitative method is widely used for evaluation of fatty degeneration. The objective of this study is to prospectively quantify fatty degeneration of the supraspinatus muscle by using 2-point Dixon technique at 3.0-T MRI, and to evaluate the correlation with severity of rotator cuff tears.

                    1191.   Magnetic Resonance Imaging of the Pulleys of the Flexor Tendons of the Toes at 11.7T

                                Monica Tafur1, Kenyu Iwasaki1, Sheronda Statum1, Christine B. Chung2, 3, Nikolaus M. Szeverenyi1, Graeme M. Bydder1

                                1Radiology, University of California, San Diego, San Diego, CA, United States; 2Radiology, VA San Diego Healthcare System, San Diego, CA, United States; 3Radiology, Univerisity of California, San Diego, San Diego, CA, United States

 

In this study, we have obtained high resolution, high field (11.7 Tesla) Magnetic Resonance (MR) images of the pulleys of the flexor tendons of cadaveric toe specimens. Although the anatomy of the pulley system has been described in one previous article, there have been no previous MRI descriptions of the pulley system of the toes published in the imaging literature. Understanding of toe pulley anatomy is likely to be of benefit in diagnosing tenosynovitis and recognizing the effects of trauma. Detailed anatomy of the pulley system of the flexor tendons allows similarities and differences between the pulley system in the foot and that in the hand to be identified. The A5 pulley, which has previously been described only in the 2nd to 5th fingers, was also present in the lesser toes. The MR visualization of the pulleys included features not seen or reported in descriptions of the finger pulleys such as the internal structure and magic angle effects. Validation was performed by direct inspection of anatomic specimens.

                    1192.   Ultra-Short Echo Time Magnetic Resonance Imaging of Rabbit Flexor Tendons in an Anterior Cruciate Ligament Reconstruction Model

                                Sarah L. Pownder1, Parina Shah2, Michael Schaer3, Richard Ma4, Xiang-Hua Deng3, Matthew F. Koff1, Scott A. Rodeo, 35, Hollis G. Potter2

                                1MRI , Hospital for Special Surgery, New York, NY, United States; 2MRI, Hospital for Special Surgery, New York, NY, United States; 3Laboratory for Soft Tissue Research, Hospital for Special Surgery, NY, United States; 4Missouri Orthopaedic Institute, University of Missouri, Columbia, MO, United States; 5Sports Medicine and Shoulder Service, Hospital for Special Surgery, NY, United States

 

Preclinical orthopaedic studies of anterior cruciate ligament reconstruction (ACLR) may allow free cage movement of animals post-operatively. The associated joint loading due to ambulation is a confounding variable that may affect graft healing. Loads which disrupt tendon collagen fibers and alter UTE T2* values have not been established. We developed a low-load rabbit ACLR model by combining unique tunnel position and pretensioning .  Similar tendon T2* values were found between mobilized and immobilized rabbits following ACLR. These data demonstrate conditions in which strain is insufficient to alter T2* values, obviating the need for immobilization in this model.

                    1193.   Micro-Imaging of Finger Tendons In Vivo Using a Dedicated Solenoidal Finger Coil at 7 T

                                Elmar Laistler1, 2, Andre Kuehne1, 2, Sigrun Goluch1, 2, Barbara Dymerska2, Jürgen Sieg1, 2, Ewald Moser1, 2

                                1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; 2MR Center of Excellence, Medical University of Vienna, Vienna, Austria

 

A highly sensitive dedicated RF coil for finger micro-imaging at 7 T is presented, suited to investigate tendons and other anatomical structures in the human finger in vivo.

Traditional Poster

Cartilage

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1194.   Significant Influences of Loading on T1 in Sub-Tissue Zones of Canine Articular Cartilage in Experimental OA

                                Jihyun Lee1, Yang Xia1

                                1Physics and Center for Biomedical Research, Oakland University, Rochester, MI, United States

 

This study aims to quantify the loading-modified topographical and zonal T1 in articular cartilage in early experimental canine OA using µMRI at the 17.6µm resolution and when the tissue was soaked with the Gd contrast agent. Both OA and mechanical compression were found to be able to alter the T1 relaxation time of articular cartilage at each sub-tissue zone and topographically, which provide a better understanding of the MRI properties of cartilage during joint loading. This result could help to design effective protocols in clinical MRI to better detect and manage the articular diseases.

                    1195.   Three-Dimensional Image Co-Registration of Mono- And Multinuclear MRI Data of Articular  Cartilage

                                Eveliina Lammentausta1, Arttu Peuna1, Pavol Szomolanyi2, Stefan Zbyn2, Siegfried Trattnig2, Miika T. Nieminen1, 3

                                1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Vienna Medical University, Vienna, Austria; 3Department of Radiology, University of Oulu, Oulu, Finland

 

We present a tool for three-dimensional MR image co-registration based on demon algorithm. According to preliminary results, it is possible to reliably co-register images obtained from the same subject at different imaging sessions acquired using different scanners at different field strengths and even multinuclear studies.

                    1196.   Quantitative MRI of Osteoarthritis for Multicenter Trials:  Standardization Between Different Centers and Manufacturers

                                Feliks Kogan1, Jarrett Rosenberg1, Emily J. McWalter1, Daniel Park2, Stephen Matzat1, Kevin Prekins2, Catherine Tran1, Merideth Taylor2, Bragi Sveinsson1, Rex Newbould2, Uche Monu1, Haonan Wang2, Neal K. Bangerter2, Garry E. Gold1

                                1Radiology, Stanford University, Stanford, CA, United States; 2Electrical & Computer Engineering, Brigham Young University, Provo, UT, United States

 

In this study, we assessed the repeatability and reproducibility of quantitative MRI measurements of cartilage morphometry and tissue parameters intra-site and between sites and manufacturers. Quantitative measurements of tissue morphometry, T2, and sodium concentration were repeatable within a given site as determined by a high concordance correlation coefficient. Between sites with different manufacturers, correlation was high for morphologic imaging. Sodium concentration measurements showed a correctable bias while use of different acquisition sequences on different platforms for T2 measurements showed errors that are not easily correctable.

                    1197.   Non-Contrast Diffusion-Weighted MRI for Detection of Synovitis Using DESS

                                Emily J. McWalter1, Bragi Sveinsson1, Edwin H. Oei1, 2, William H. Robinson1, Mark C. Genovese1, Garry E. Gold1, Brian A. Hargreaves1

                                1Stanford University, Stanford, CA, United States; 2Erasmus MC, Netherlands

 

Synovitis is frequently observed osteoarthritis and is characterized by synovial thickening and joint effusion. Contrast enhanced T1-weighted imaging is the current gold standard for detecting synovitis; however, introducing contrast enhanced images at the end of a knee protocol increases time, cost and risk to patients.  We propose double echo in the steady state (DESS) imaging for synovitis detection without the need for administration of an intravenous contrast agent and demonstrate that with a linear combination of the DESS echoes, improved contrast between the synovial membrane and fluid can be achieved.

                    1198.   Morphologic MRI Findings Related to New Pain Development Over a Period of 4 Years – Data from the Osteoarthritis Initiative

                                Stephanie Hou1, Lorenzo Nardo1, Ursula Heilmeier1, Sonia Lee1, John Lynch1, Chuck McCulloch1, Gabby Joseph1, Thomas Link1

                                1UCSF, San Francisco, CA, United States

 

This longitudinal study identified morphological MRI findings correlated with development of new pain over a period of 4 years in the knees of subjects at risk for osteoarthritis.  The following findings were significantly associated with pain:  baseline medial tibial cartilage pathology, baseline medial meniscus body pathology, incident effusion, and progressive patella cartilage pathology.  Trends suggested an association of the following findings with pain:  baseline medial tibia bone marrow edema pattern, medial femoral condyle bone marrow edema pattern at 4 years, and anterior medial meniscus pathology at 4 years.  These associations may help radiologists to better guide clinical treatment.

                    1199.   In Vitro Micro-Imaging Investigation of Osteoporotic and Osteoarthritis Femoral Specimens by Means of Internal Magnetic Field Gradient (IMFG)

                                Giulia Di Pietro1, 2, Eleonora Piccirilli2, Monica Celi2, Umberto Tarantino2, Silvia Capuani, 3

                                1IIT@Sapienza, Physics Department, “Sapienza” University, Rome, Italy; 2Department of Orthopaedics and Traumatology, University of Rome “Tor Vergata”, Rome, Italy; 3CNR IPCF UOS Roma, Physics Department, “Sapienza” University , Rome, Italy

 

In this in vitro study performed at 9.4T, the internal magnetic field gradient (IMFG) was used to discriminate between femoral neck samples extracted from osteoporotic (OP) and osteoarthritic (OA) patients. IMFG values were lower in OP compared to OA suggesting a higher trabecular density in OA specimens. IMFG values were lower in the metaphysis compared to subchondral section in both OP and OA samples. These results are in agreement with the packing of subchondral bone occurring in OA. In subchondral section of OP specimens the higher IMFG values are due to the marrow fat content increase

                    1200.   Registration-Based Motion Correction in Time-Series Studies of Bone Microarchitecture and Mechanics

                                Ning Zhang1, Jeremy F. Magland1, Chamith S. Rajapakse1, Hee Kwon Song1, Felix W. Wehrli1

                                1University of Pennsylvania, Philadelphia, PA, United States

 

Subject motion degrades image quality. Intra-scan subject motion can further mask detectability of treatment effects in time-series studies. Here we present a registration-based technique designed to retrospectively correct for rigid-body intra-scan subject motion. Results from in-vivo micro-MR images of the distal radius show significant improvements in both image quality and serial reproducibility on image-derived trabecular bone micro-structure and biomechanics compared to the navigator-based and autofocusing techniques.

                    1201.   Fully Exploiting the PILS Effect for High Performance Joint Imaging: Benefits of Coil Arrays with S/I Sensitivity

                                Habib Al saleh1, Richard Kijowski2, Walter F. Block3, 4

                                1Medical Physics, University of Wisconsin, Madison, WI, United States; 2Radiology, University of Wisconsin , Madison, WI, United States; 3Medical Physics, University of Wisconsin , Madison, WI, United States; 4Biomedical Engineering , University of Wisconsin , Madison, WI, United States

 

For a single row, phased array knee coil, the azimuthal coil arrangement reduces sensitivity in the transverse plane and hence the PILS effect reduces the number of radial lines required to fully sample an axial slice. However, accelerating volumetric scans is limited as the coil arrangement provides no variation in sensitivity in the S/I dimension . We compare the impact of a multiple row arrangement against a single coil design in 3D radial joint imaging through the following 2 studies:  1) varying the undersampling factor for a given resolution while maintaining the same stochastic noise level and 2) a comparison of image quality with challenging 0.33 mm isotropic resolution scan in 8 minutes. Preliminary results demonstrate significantly higher image through use of a multiple row coil with S/I sensitivity.

                    1202.   Evaluation of a Collagen-Gel Based Cartilage Repair Method Using Zonal Variation in T2-Mapping and DGEMRIC

                                Martin Brix1, 2, David Stelzeneder1, Stephan Domayer3, Stefan Nehrer4, Thomas Luksch4, Götz Welsch5, Martina Schinhan1, Catharina Chiari1, Sebastian Apprich1, Reinhard Windhager1, Siegfried Trattnig2

                                1Department of Orthopaedics, Medical University of Vienna, Vienna, Austria; 2High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; 3Sonderkrankenanstalt Zicksee, Austria; 4Danube University Krems, Krems, Austria; 5Department for Trauma Surgery, University Hospital Erlangen, Erlangen, Germany

 

The aim of our study was to assess the repair tissue structure after a matrix associated autologous chondrocyte transplantation technique using biochemical MRI. Fourteen knees of 14 patients were assessed in that cross-sectional study at a mean follow up of 2.0 ± 0.9 years. The results demonstrated a zonal variation not only in T2-maps, but also in dGEMRIC images. This suggests a gradual increase in proteoglycan content of repair tissue from the superficial to the deep layer.

                    1203.   Diffusion of Manganese Oxide Nanoparticles Into Articular Cartilage

                                Susanna Ahola1, Ville-Veikko Telkki1, Eveliina Lammentausta2, Jessica M. Rosenholm3, Elli-Noora Salo2, Gamzegul M. Behrouz1, Roberto Blanco Sequeiros2, 4, Miika T. Nieminen2, 4

                                1Department of Physics, University of Oulu, Oulu, Finland; 2Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 3Centre of Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Turku, Finland; 4Department of Radiology, University of Oulu, Oulu, Finland

 

Feasibility of new manganese oxide nanoparticles (MnOx) as contrast agent for articular cartilage was investigated in vitro. The diffusion of MnOx into articular cartilage was followed by measuring T1 maps for 24 hours at repeated intervals after immersing osteochondral samples into the MnOx and, subsequently, after immersing the sample in saline solution for another 24 hours. For comparison, the post-contrast part of the study was repeated with Gd-DTPA solution. MnOx diffused rapidly into cartilage and appears to permanently bind in high concentration to a region near the calcified zone. Thus MnOx is a potential biomarker for highlighting the cartilage-bone interface.

                    1204.   Incorporation of Rician Noise in the Analysis of Biexponential Transverse Relaxation in Cartilage Using a Multiple Gradient Echo Sequence at 3T and 7T

                                Mustapha Bouhrara1, David A. Reiter1, Hasan Celik1, Jean-Marie Bonny2, Vanessa Lukas1, Kenneth W. Fishbein1, Richard G. Spencer1

                                1NIA, NIH, Baltimore, MD, United States; 2QuaPa, INRA, Saint Genès Champanelle, France

 

The noise distribution of magnitude MR data obtained through quadrature detection exhibits a Rician, rather than Gaussian, probability distribution.  Previous work has assessed the importance of thisin fitting monoexponential decay curves.  Recently, there has been a renewed interest in tissue compartmentation studies through use of multiexponential analysis.  Accordingly, we extend the analysis of the effect of Rician noise to the much more complex problem of biexponential decay through use of Monte Carlo simulations, and phantom and cartilage explant studies.  We find that explicit incorporation of the Rician statistical characteristics of the signal leads to markedly improved results.

                    1205.   Sodium MRI of Cartilage Repair Tissue in the Ankle Joint at 7T

                                Stefan Zbyn1, Stephan E. R. Domayer2, Martin O. Brix1, 2, Sebastian Apprich1, 2, Jochen G. Hofstaetter2, Sonja M. Walzer2, Vladimir Mlynarik1, Vladimir Juras1, Reinhard Windhager2, Siegfried Trattnig1

ISMRM_MagnaLogo.jpg                                 1High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria; 2Department of Orthopedics, Medical University Vienna, Vienna, Austria

 

To our best knowledge, this is the first report on employing sodium (23Na) MRI for the evaluation of native cartilage and cartilage repair tissue in the ankle joint. Data from cadaver ankle samples demonstrate that 23Na MRI is sensitive to changes in the GAG content of thin tibial and talar cartilage in the ankle. Observed 23Na concentrations in the volunteers are in agreement with previous findings, and demonstrate feasibility of the quantification of 23Na concentration in cartilage of the ankle joint at 7T. 23Na MRI may be useful for the noninvasive evaluation of the repair tissue in the ankle joint.

                    1206.   K-Means Clustering of Multi-Parametric MRI Data for Improved Classification of Articular Cartilage Degeneration

                                Victor Casula1, Simo Saarakkala2, Elli-Noora Salo2, Jari Rautiainen1, Virpi Tiitu3, Olli-Matti Aho4, Petri Lehenkari4, Jutta Ellermann5, Mikko J. Nissi5, Miika T. Nieminen1

                                1Department of Radiology, University of Oulu, Oulu, Finland; 2Department of Diagnostic Radiology, University of Oulu, Oulu, Finland; 3Institute of Biomedicine, Anatomy, University of Eastern Finland, Kuopio, Finland; 4Department of Anatomy and Cell Biology, University of Oulu, Oulu, Finland; 5Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

 

In this study k-means clustering algorithm was applied to multiparametric MRI data to classify normal and degenerated articular cartilage. Various MRI parameters were assessed at 9.4 T in intact and degraded human cartilage samples and enzymatically degraded bovine cartilage samples. OARSI grading was used as reference for human cartilage. High sensitivity and specificity were achieved using several combinations of two parameters. The best classification involved rotating-frame techniques. Similar results were obtained with combinations of three parameters with no improvements in terms of specificity and sensitivity.

                    1207.   MRI Morphological and Quantitative Evaluation of Knee Allograft Repair at 3, 6 and 9 Months Post-Op: Early Surveillance Demonstrates Nascent Physiological Incorporation of Allograft Material in Pain Free Patients

                                Joshua Michael Farber1, Saara Totterman2, Jose Tamez-Pena3, Eric Brandser4, Edward Schreyer2, Bruce Holladay5

                                1Radiology, Qmetrics Technologies., Cincinnati, OH, United States; 2Radiology, Qmetrics, Rochester, NY, United States; 3Bio Sciences, Tec De Monterry, Monterry, Mexico; 4Radiology, Radiology Ass. of N KY, KY, United States; 5Orthopaedic surgey, Commonwealth Orthopaedic Centers, Edgewood, KY, United States

 

Allograft procedures for knee articular cartilage defect repair are becoming common, almost routine.  This paper examines the appearance of successful and failed grafts to study the process of graft incorporation and to develop imaging biomarkers for successful graft incorporation.

                    1208.   Accelerating T1-Rho Cartilage Imaging Using K-T ISD with Locally-Adapted Thresholding and JSENSE

                                Yihang Zhou1, Valentina Pedoia2, Julien Rivoire2, Yanhua Wang3, Dong Liang4, Xiaojuan Li2, Leslie Ying3

ISMRM_MagnaLogo.jpg                                 1Department of  Biomedical Engineering, Department of Electrical Engineering, The State University of New York at Buffalo, Buffalo, NY, United States; 2Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, United States; 3Department of Biomedical Engineering, Department of Electrical Engineering, The State University of New York at Buffalo, Buffalo, NY, United States; 4Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China

 

In this study, the feasibility of combining compressed sensing (CS) with parallel MRI (pMRI) in accelerating the T1&#961; cartilage imaging is investigated. K-t ISD with locally-adapted thresholding, named k-t LISD, combined with JSESNE is used to reconstruct the image sequence from undersampled data in (k, t) space. The reconstruction process alternates iteratively between k-t LISD for reconstruction of the image sequence and JSENSE for sensitivity estimation. Result on in-vivo human knee experiment shows the T1&#961; quantification from the accelerated acquisition using the proposed method is consistent with that from full acquisition in all cartilage compartments.

                    1209.   Evaluation of New Software for Cartilage Thickness Estimation in Knee MR Images with Severe Metallic Artefact

                                Ryan Nazareth1, Peter Cashman2, Pauline Parlier2, Annie Papadaki3, Lesley Honeyfield3, Keshthra Satchithananda3, Donald McRobbie3, Fiona Watt4

                                1Imperial College Healthcare NHS Trust, London , United Kingdom; 2Imperial College London, London, United Kingdom; 3Imperial College Healthcare NHS Trust, London, United Kingdom; 4Kennedy Institute of Rheumatology, Oxford, United Kingdom

 

Monitoring cartilage thickness change is desirable in individuals with knee injuries who are at high risk of early osteoarthritis. The segmentation of cartilage from knee MR images is greatly complicated by the presence of metal artefacts. Here, we present a semi-automated in-house software which can accurately segment cartilage boundaries and estimate cartilage thickness, provided the metal artefact is only contained with the bone. This software offered the same level of accuracy and precision compared to manual tools used by radiographers but with a substantial reduction in time, robustness to changes in display contrast and brightness, and excellent inter-observer agreement.

                    1210.   MR T2 Values of the Knee Cartilage and Meniscus in Chronic Kidney Disease

                                Shih-Wei Chiang1, 2, Hsiao-Wen Chung1, Chao-Ying Wang2, Yi-Chih Hsu2, Guo-Shu Huang2

                                1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 2Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan

 

Chronic kidney disease (CKD) is associated with a wide range of disorders of mineral and bone metabolism. Understanding the pathophysiology in mineral metabolism and bone diseases is very important, as recent evidence has suggested the concept of bone-vascular axis in CKD. Our preliminary findings suggest that CKD-related T2 changes in the medial meniscus may precede alterations in other cartilage regions.

                    1211.   Multiparametric Therapy Study of the Goat Cartilage After Inducing Osteoarthritis

                                Joachim Hermann Xaver Schrauth1, 2, Gunthard Lykowsky1, 2, Daniel Weber1, Jakob Kreutner1, 2, Kathrin Hemberger1, 2, Lars Rackwitz3, Ulrich Nöth3, Peter Jakob1, 2, Daniel Haddad1

                                1Molecular & Cellular MRI, MRB Research Center for Magnetic Resonance Bavaria, Wuerzburg, Bavaria, Germany; 2Experimental Physics 5 (Biophysics), University Wuerzburg, Wuerzburg, Bavaria, Germany; 3König-Ludwig-Haus, Orthopädische Universitätsklinik Würzburg, Wuerzburg, Bavaria, Germany

 

The aim of this study was to compare Sodium, T1&#961; and dGEMRIC measurements for the characterization of the goat cartilage after inducing Osteoarthritis in a control and cell based treated group. The results of all methods show expected behavior over the course of 16 weeks after the defect, though T1&#961; seems to be most sensitive to early changes in the cartilage. Moreover we found a very strong correlation between the both known dGEMRIC indices and moderate correlations between Sodium & dGEMRIC(1), dGEMRIC(1) & T1&#961; and dGEMRIC(2) & T1&#961;.

                    1212.   Magnetic Resonance Imaging of Viscosupplementations: A Preliminary Report

                                Mohammad Haris1, 2, Anup Singh1, Kejia Cai1, 3, J. Bruce Kneeland, Fotios Tjoumakaris4, Hari Hariharan1, Ravinder Reddy1

                                1CMROI, Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Research Branch, Sidra Medical and Research Center, Doha, Qatar; 3CMRR 3T Research Program, University of Illinois at Chicago, Chicago,  IL, United States; 4Sports Medicine at Rothman institute, Thomas Jefferson University Hospital, Philadelphia, PA, United States

 

The concept of viscosupplementation has gained widespread acceptance as a new treatment for the management of osteoarthritis (OA) of the knee. Here, we evaluate the chemical-exchange-saturation-transfer effect from the two popular viscosupplementations (Synvisc and Orthovisc) by exploiting the exchangeable hydroxyl groups present on these molecules at 7T human scanner. Both viscosupplementations showed a strong CEST effect at ~1 ppm. Furthermore, using the CEST technique it may possible to map the fate of the injected viscosupplementation in knee joints of OA patients over time as well as their effect on knee cartilage GAG concentration.

                    1213.   Evaluation of the BOLD Signal in Response to CO2 or O2 in JIA Patients at 3T: A Pilot Study

                                Afsaneh Amirabadi1, Adrian Crawley2, Carina Man1, Tammy Rayner1, Ruth Weiss1, Joseph Fisher, 23, Andrea Doria1, 4

                                1The Hospital for Sick Children, Toronto, ON, Canada; 2The University Health Network, ON, Canada; 3Thornhill Research Inc., ON, Canada; 4University of Toronto, ON, Canada

 

Juvenile idiopathic arthritis is the most frequent chronic rheumatologic disease of childhood.  Early diagnosis may improve therapy efficacy and decrease adverse outcomes. In the acute arthritis increased metabolic demand and the inadequate oxygen delivery through the inflamed synovium result in hypoxia. In this study 3T BOLD MRI was used to obtain functional information of the periarticular tissue reactivity in response to local hypoxia which is directly relevant to the pathogenesis of arthritis. End-tidal gas concentrations were manipulated using a model-based prospective targeting device during BOLD MRI. The results showed non statistically significant percent signal change difference between inflammatory and healthy tissue.

 

                    1214.   Tensor Based Morphometry to Evaluate Longitudinal Changes in the Femoral Cartilage of Subjects with Osteoarthritis:  Data from the Osteoarthritis Initiative (OAI).

                                Uyen Hoang1, Usha Sinha2

                                1Bio-informatics, SDSU, San Diego, CA, United States; 2Physics, SDSU, San Diego, CA, United States

 

Osteoarthritis causes among other changes, loss in cartilage volume which increases as the disease progresses.  Cartilage loss with disease progression is small and localized to sub regions of the cartilage, making detection challenging.    We report the deformation (Jacobian) maps of femoral cartilage in a longitudinal study (baseline and 12 mo.) to identify subtle and localized interval changes.  Subject data from the Osteoarthritis Initiative which had segmented cartilage in longitudinal studies was used.  The Jacobian maps allow visualization of small and localized changes and could potentially enable population based studies on cartilage morphometry.

                    1215.   The Origin That Darkens the Deep Region of Articular Cartilage in MRI When Loaded at the Magic Angle

                                Yang Xia1, Nian Wang1

                                1Physics and Center for Biomedical Research, Oakland University, Rochester, MI, United States

 

To investigate the molecular origin that darkens the deep-region of articular cartilage when the tissue is compressed and oriented at the magic angle, T2 and T1&#961; experiments were used to study native and degraded cartilage. The glycosaminoglycan (GAG) concentrations in the specimens were quantified by both sodium ICP-OES and T1-Gd methods. The GAG concentration was found to play the key role in the formation of this low-intensity layer in the deep-region of the compressed cartilage. A schematic model has been formulated to explain the structural differences in the deformation of the collagen matrix between native and degraded tissues.

                    1216.   Multiband Slice Accelerated TSE for High Resolution Knee Imaging

                                Dingxin Wang1, 2, Abraham Padua Jr3, Jutta Ellermann2, Xiufeng Li2, Kamil Ugurbil2, Vibhas Deshpande4

                                1Siemens Medical Solutions USA, Inc., Minneapolis, MN, United States; 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 3Siemens Medical Solutions USA, Inc., Houston, TX, United States; 4Siemens Medical Solutions USA, Inc., Austin, TX, United States

 

Our study demonstrates the clinical application of multiband slice accelerated TSE combined with in-plane parallel imaging for high resolution knee imaging at 3T. Multiband slice acceleration improves the acquisition efficiency of TSE. A total of 4 times acceleration can be achieved using an 8-channel knee coil.

                    1217.   Evaluation of MT Asymmetry Under Spin-Lock Condition in Rabbit Disc and Bovine Cartilage

                                Wen Ling1, Rob Hartman2, Tao Jin1, Nam Vo2, Gwendolyn Sowa2, James Kang2, Michel Modo1, Kyongtae Ty Bae1

                                1Dept. of Radiology, UPMC, Pittsburgh, PA, United States; 2Dept. of Orthopaedic Surgery, UPMC, Pittsburgh, PA, United States

 

The applicability of CEST on intervertebral disc is highly dependent on the knowledge of MT asymmetry. The MT asymmetry of disc and cartilage was evaluated under spin-lock condition with different pair of RF power / duration in rabbit discs and bovine cartilage.

                    1218.   Assessment of Inflammatory Component in the Mono-Iodoacetate (MIA) Model of Osteoarthritis by MRI

                                Thomas Kaulisch1, Laura Corradini2, Detlef Stiller3

                                1Target Discovery Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Baden-Württemberg, Germany; 2CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Baden-Württemberg, Germany; 3Target Discovery Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Baden-Württemberg, Germany

 

The Mono-Iodoacetate (MIA) model is an attractive tool for testing novel compounds at different stages of progressive osteoarthritis (OA) development. We characterize the inflammatory component by means of MRI-based volumetry and DCE-MRI and demonstrate treatment effects when using Celecoxib.

Traditional Poster

Muscle

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1219.   BOLD MRI of Lower Extremity Muscles : Venous Insufficiency Is Affecting BOLD Signal

                                Hatice T. SANAL1, Sertan GEZGIN1, Cem TAYFUN2

                                1Radiology, Gulhane Military Medical Academy, ANKARA, Kecioren, Turkey; 2Radiology  , Gulhane Military Medical Academy (R), ANKARA, Kecioren, Turkey

 

Several parameters on T2* time-intensity curves, obtained from lower extremity muscles of patients having arterial occlusive disease and healthy volunteers, have been evaluated through BOLD MR imaging. 

 

Time to peak (TTP) value longer than 40 sec suggest insufficient blood sources to the muscle with a sensitivity and specificity of % 83.3, % 92.3, respectively. Interestingly, in one volunteer with normal artrerial system but with venous insufficency, TTP was longer than expected. TTP value with a threshold of 40 sec, can exclude stenosis with a great sensitivity, unless venous insufficiency is exluded.

 

                    1220.   Upper Limb Muscle Fat-Water Quantification in Non-Ambulant Duchenne Muscular Dystrophy

                                *Valeria Ricotti1, *Matthew RB Evans2, Christopher DJ Sinclair2, Jasper M. Morrow2, Jordan W. Butler1, Robert L. Janiczek3, Michael G. Hanna2, Paul M. Matthews3, Tarek A. Yousry2, Francesco Muntoni1, 2, John S. Thornton2

                                1Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom; 2MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; 3GlaxoSmithKline, London, United Kingdom

 

Assessing dystrophin restoration in the muscle of DMD patients undergoing experimental gene therapies requires an invasive muscle biopsy. MRI may provide a non-invasive alternative to evaluate response to therapy; however the natural course of DMD muscle changes needs to be established. Examination of the upper limb will allow recruitment of ambulant and non-ambulant patients in clinical trials. Eight non-ambulant DMD patients and 10 healthy controls underwent 3-point Dixon fat-fraction forearm  imaging revealing significantly higher fat fraction and muscle atrophy in DMD. Additionally, duration of non-ambulation and wrist extension myometry correlated with MRI indices. MRI is a potential biomarker for evaluating DMD progression.

                    1221.   Evaluation of Vastus Lateralis Muscle Fat Fraction Measured by Two-Point Dixon Water-Fat Imaging and 1H-MRS

                                Sunil K. Valaparla1, 2, Erika M. Ripley2, Goldie R. E. Boone2, Timothy Q. Duong1, Geoffrey D. Clarke, 12

                                1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States; 2Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

 

1H-MRS and two-point Dixon MRI provide reliable fat fraction, correlating well with tissue biopsies. This study compared fat fraction in human vastus lateralis (VL) using Dixon MRI and long TE 1H-MRS at 3T. Fat fraction exhibited considerable inter-individual variability for 1H-MRS FF (%) = 3.61 ± 2.25 (range: 1.34 – 7.23) and Dixon MRI FF (%) = 3.11 ± 1.17 (range: 1.77 – 5.60). Linear regression analysis showed good correlation (r = 0.8746) between FF (%) from two methods. These methods can provide insight on muscular fat interference with insulin signaling in diabetes and give a reliable basis for longitudinal clinical studies.

                    1222.   Multi-Component T2* Mapping in the Calf Muscle During Plantar Flexion Using a Multi-Echo Radial GRE Sequence

                                Patrick Hiepe1, Martin Krämer1, Alexander Gussew1, Jürgen R. Reichenbach1

                                1Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital, Jena, Germany

 

The aim of the present study was to apply a radial multi-echo gradient-echo (GRE) sequence during dynamic exercising for continuous quantitation of the effective transverse relaxation time constant (T2*) enabled by the increased robustness of radial trajectories against motion artefacts. Load-induced T2*-changes were determined based on mono-exponential and multi-component signal fitting of data obtained in a human calf during plantar flexion.

 

                    1223.   MRI Validation of a Transcriptional Cascade Propagation Model in FSHD Muscular Dystrophy

                                Barbara Janssen1, Nicoline Voet2, Alexander Geurts2, George Padberg3, Baziel van Engelen3, Arend Heerschap1

                                1Radiology, Radboud University Medical Center, Nijmegen, Gelderland, Netherlands; 2Rehabilitation, Radboud Univeristy Medical Center, Nijmegen, Gelderland, Netherlands; 3Neurology, Radboud Univeristy Medical Center, Nijmegen, Gelderland, Netherlands

 

DUX4 expression by a genetic abnormality is believed to cause fascioscapulohumeral muscular dystrophy (FSHD), however the mechanism leading to muscle pathology remains unknown. We present MRI findings that validate a dynamic model with DUX4 initiation and propagation of a transcriptional cascade in myofibers. The majority of muscles in patients are either normal or highly fat infiltrated, indicating an abrupt transition to a diseased state, which agrees with clinical observation. As predicted by the model we identified a minor muscle fraction with intermediate fatty infiltration, which occurs as a longitudinal muscular gradient and shows fast progression of the fatty infiltration.

                    1224.   Effect of Anisotropic Smoothing on DT-MRI-Based Fiber Tractography in the Medial Gastrocnemius Muscle

                                Amanda K. W. Buck1, Zhaohua Ding1, 2, Christopher P. Elder1, Theodore F. Towse, 13, Bruce M. Damon1

                                1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States; 2Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, United States; 3Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN, United States

 

DT-MRI-based fiber tractography allows non-invasive estimation of three-dimensional muscle architecture; however, DT-MRI in the leg suffers from low SNR, which can introduce error in the estimation of diffusion tensor eigenvectors used for tract propogation.  This study assesses the effect of anisotropic smoothing on fiber tracking measures in the medial gastrocnemius muscle in healthy subjects.

                    1225.   A Novel MR Compatible Indentation Setup to Study the Etiology of Pressure Ulcers and Related Deep Tissue Injury.

                                Jules L. Nelissen1, Willeke A. Traa2, Larry A. de Graaf1, Kevin M. Moerman3, Aart J. Nederveen3, Cees W. Oomens2, Klaas Nicolay1, Gustav J. Strijkers1

                                1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Soft Tissue Biomechanics and Engineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 3Department of Radiology, Amsterdam Academic Medical Center, Amsterdam, Netherlands

 

A novel MR compatible indentor was designed, build and tested to provide new insights in the etiology of pressure ulcer related deep tissue injury. The design allows flexible positioning of the indentor and was tested by applying 2h sustained mechanical loading to the tibialis anterior (TA) muscle of rat inside a MR scanner. T2 weighted scans, T2 maps and angiography were used to assess skeletal muscle injury and physiological changes. Hyperenhancement due to the formation of edema, resembling the structure of vasculature in the TA muscle is observed in strong T2weighted scans. T2 maps show the similar capillary bed structure.

                    1226.   Fat-Signal Fraction Quantification of Paravertebral Muscle Using T2*-Corrected Multi-Echo Dixon Technique

                                Yeon Hwa Yoo1, Yaena Kim1, Young Han Lee2, Mun Young Paek3, Sungjun Kim1, Tae-Sub Chung1, Choon-Sik Yoon1, Ho-Taek Song2, Jin-Suck Suh2

                                1Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine., Seoul, Korea; 2Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; 3Siemens Ltd. Seoul, Seoul, Korea

 

Fat-signal fraction has been quantified for phantom and variable tissues using variable sequences based on Dixon techniques. Recently, fat-signal fraction mapping using multi-echo Dixon techniques have been developed for further improvement of accuracy. However, there has been no consensus whether T2*-corrected multi-echo Dixon technique can more accurately measure fat-signal fraction in skeletal muscle as compared with the 2-echo and 3-echo techniques particularly when T2*-correction is added, albeit being expected so. This study is the first one that T2*-corrected multi-echo Dixon technique is superior to the sequences previously tested for the purpose.

                    1227.   A BOLD Effect on Different Calf Muscle Groups in Elderly Females

                                Chenfei Ye1, James F. Griffith2, Heather T. Ma1, David K. Yeung2, Alvin F. Li2, Xu Xing1

                                1Department of Electronic and Information Engineering, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong, China; 2Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong

 

This study examined the BOLD effect on calf muscles in elderly subjects to investigate the oxygenation characteristics in different calf muscle groups for the elderly females. Temporary vascular occlusion was induced with air-cuff compression of the thigh and BOLD-MRI data curve was fitted to derive quantitative parameters. The BOLD signal in soleus muscle showed the lowest minimum ischemic value during ischemia and the steepest slope during hyperemia. As soleus muscle is mainly composed by slow-twitch oxidative muscle fibers, current results may be due to a higher vascular bed density and better endothelial function in such muscle.

                    1228.   NMR Based Biomarkers to Study Aging Related Changes in the Human Quadriceps

                                Noura Azzabou1, Jean-Yves Hogrel2, Yoann Barnouin2, Pierre G. Carlier1

                                1AIM-CEA Institut de Myologie, Laboratoire RMN, Paris, France; 2AIM, Institut de Myologie, Laboratoire de physiologie et d'évaluation neuromusculaire, Paris, France

 

In order to study the impact of aging on the skeletal muscle, we suggested several NMR based parameters that are water T2 values and heterogeneity indices related to water T2 changes. We evaluated this parameter on the quadriceps muscles of healthy young adults and older one. In addition to age, we considered the gender and physical activity factors. Results showed that water T2, and heterogeneities were higher for elderly group. Furthermore, a regular physical activity maintained lower muscle T2 values and heterogeneity indices. These findings may be related to the progressive atrophy and rarefaction of type II fibers with age.

                    1229.   Post-Contractile Blood-Oxygenation Level Dependent (BOLD) Contrast in Skeletal Muscle at 7T

                                Theodore F. Towse1, 2, Christopher P. Elder3, 4, Emily C. Bush5, 6, Benjamin T. Childs5, Samuel W. Klockenkemper5, Shea A. Sabin5, Jared T. Bullock5, Bruce M. Damon7, 8

                                1Physical Medicine and Rehabilitation , Vanderbilt University, Nashville, TN, United States; 2Vanderbilt Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 3Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN, United States; 4Radiology and Radiological Sciences, TN, United States; 5Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 6Vanderbilt University Biomedical Engineering, TN, United States; 7Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States; 8Molecular Physiology and Biophysics, Vanderbilt University, TN, United States

 

Post-isometric contraction proton density and T2*-weighted signal transients acquired at 3T have been used to characterize muscle microvascular function in both the normal and pathologic states. At 7T, muscle BOLD contrast is expected to be more influenced by extravascular BOLD mechanisms than is observed at 3T, where muscle BOLD contrast is dominated by intravascular mechanisms. Our preliminary studies suggest BOLD based functional imaging of muscle is feasible at 7T and may afford greater insight into microvascular dysfunction by offering greater specificity to microvascular-scale structures and a higher contrast-to-noise ratio than are achieved at lower field strengths.

                    1230.   Metabolic Adaptations in Muscle After Short Bout Exposure to Recreational Football: An Intervention Study in Sedentary Pre-Menopausal Women.

                                Suzanne Scott1, Luke Connolly1, Sarah Jackman1, Jonathan Fulford2, Karen Knapp3, Jude Meakin3, Rosey Davies1, Peter Krustrup1

                                1Sports and Health Science, University of Exeter, Exeter, United Kingdom; 2Exeter NIHR Clinical Research Facility, University of Exeter, Exeter, United Kingdom; 3CEMPS, University of Exeter, Exeter, United Kingdom

 

Adherence to exercise interventions aimed at improving cardiac health in sedentary women may be affected by lack of time to exercise.

This study evaluated the efficacy and acceptability of short-bout football training (twice weekly for 13.5 min. over 16 weeks) in sedentary pre-menopausal women using 31P spectroscopy to assess metabolic adaptations in muscle.

Results indicated a significant increase in time-to-failure on a ramp muscle test and a significantly higher end-exercise PCr value in participants after exposure to the training intervention.

Evidence that shorter training regimes improve cardiac health may reduce barriers to exercise and increase compliance in target populations.

 

 

                    1231.   Using 31P-MRS to Explore the Effects of Iron Deficiency on Murine Skeletal Muscle Function and Metabolism During Exercise

                                M. Kate Curtis1, Lowri E. Cochlin2, Mark A. Cole3, David P. O'Neill1, Michael S. Dodd1, 4, Damian J. Tyler1, 4, Kieran Clarke1, Peter A. Robbins1

                                1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom; 2Department of Physiology, Anatomy and Genetics, PulseTeq Ltd, Oxford, United Kingdom; 3Department of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom; 4Oxford Centre for Clinical Magnetic Resonance Research, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom

 

Physical work or exercise capacity has been widely reported as being impaired by iron deficiency in both human and animal studies. The aim of this project was to develop a technique that allows for the simultaneous assessment of force production, fatigue resistance and metabolic function of murine gastrocnemius muscle during exercise. To address this, a method of in vivo gastrocnemius muscle stimulation was successfully established, which allows the simultaneous measurement of energetics, by 31P MRS, and induced force production in a murine model of altered iron status.

                    1232.   Measurement of Trabecular Bone Quality In Vivo Using Decay Due to Diffusion in the Internal Field (DDIF) MRI

                                Sara Maria Sprinkhuizen1, Miriam Bredella2, Martin Torriani2, Anne Klibanski3, Pouneh K. Fazeli3, Scott Daley2, Ela Jane Cross3, Jerome Ackerman1, Yi-Qiao Song1, 4

                                1MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 2MGH Musculoskeletal Imaging, MA, United States; 3MGH Neuroendocrine Unit, MA, United States; 4Schlumberger-Doll Research, Cambridge, MA, United States

 

Bone quality is currently measured with dual energy x-ray absorptiometry (DXA), which assesses the bone mineral density (BMD). However, BMD is just one of several factors contributing to bone quality. The microstructural geometry of bone is another, very important, factor in determining bone strength and can be measured using Decay due to Diffusion in the Internal Field (DDIF) MRI. The current work was aimed at understanding the relation between DDIF MRI and clinical BMD values. The DDIF technique was applied in the lumbar spine of healthy controls and patients with anorexia nervosa and compared to BMD values obtained using DXA.

                    1233.   Disc Location Dependence of the Proteoglycan (PG) T2 Value in Human Lumbar Intervertebral Disc

                                Anna M. WANG1, 2, Iris Y. Zhou1, 2, Adrian Tsang1, 2, Ivy W. Han1, 2, Ed X. Wu1, 2

                                1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong

 

This study explored the capability of proteoglycan (PG) T2 value as a marker of the intervertebral disc degeneration (IVDD). PG T2 and water T2 value, as well as PG/water ratio were measured on 4 different disc levels of lumbar spine. The PG T2 value showed a slightly increasing trend from the upper disc level to the lower disc level. The significant difference of PG T2 value was found between disc L3-4 and disc L4-5 while the water T2 and PG/water ratio showed no statistical significant change between disc levels. Our result suggests the increased PG T2 value could be the reflection of disc degeneration taken place. Demonstrated by this preliminary study, the PG T2 measurement on clinical scanner is highly feasible and the PG T2 value might be a potential marker for the early detection of disc degeneration.

                    1234.   Fat Quantification in Back Muscles with Low Lipid Content: A Comparison of SVS, CSI and Dixon Measurements

                                Gaëlle Diserens1, Mauricio Reyes2, Chris Boesch1, Peter Vermathen1, Waldo Enrique Valenzuela2

                                1Depts Clinical Research and Radiology, University Bern, Bern, Switzerland; 2Institute for Surgical Technology and Biomechanics, Bern University, Bern, Switzerland

 

The aim of this study was to compare fat quantification determined by Dixon MRI, SVS and CSI in a back muscle (psoas major) in healthy subjects for small amounts of lipids only. A strong correlation was obtained for SVS and CSI results, but spectroscopy results didn't significantly correlate with Dixon results. Back muscle low fat content quantification can reliably be quantified by spectroscopy MR techniques (SVS and CSI), while noise and artefacts limit the preciseness of Dixon MRI for low fat quantification.

                    1235.   Characterization of Metabolic Response to Ischemia in Skeletal Muscle of Non-Obese Early Stage Type 2 Diabetic Rats by In Vivo 31P MRS and BOLD MRI

                                Yuchi Liu1, Xunbai Mei1, Nicola Lai1, 2, Xin Yu1, 3

                                1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; 2Pediatrics, Case Western Reserve University, OH, United States; 3Radiology, Case Western Reserve University, OH, United States

 

This study investigated the metabolic response to ischemia in skeletal muscle of non-obese early stage type 2 diabetic rats.  31P spectra and BOLD images were acquired in an interleaved fashion at baseline, during 25-min ischemia, and 20-min reperfusion. The diabetic group showed less reduction in phosphocreatine (PCr) and less increase in inorganic phosphate (Pi) during ischemia.  Diabetic rats also showed greater signal reduction in BOLD images during ischemia, possibly due to increased oxygen extraction.  Both diabetic and control groups have similar PCr recovery kinetics during reperfusion.  These data suggest that mitochondrial function may remain normal in early stage type 2 diabetes.

                    1236.   31P Wideband Inversion Transfer for Measuring ATP Synthesis Rates in Human Skeletal Muscle

                                Jimin Ren1, Baolian Yang2, A. Dean Sherry1, 3, Craig R. Malloy1, 4

                                1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Philips Healthcare, OH, United States; 3University of Texas at Dallas, Richardson, TX, United States; 4VA North Texas Health Care System, TX, United States

 

There has been a long-standing interest in measuring ATP synthesis rates in vivo.  Conventional 31P saturation transfer requires prolonged saturation of gamaATP while inversion transfer by selective-inversion of gamaATP is less efficient, all due to rapid leaking of magnetization to other spins in the exchange network, especially phosphocreatine(PCr). Wideband inversion overcomes this problem by simultaneously inverting both PCr and ATP spins, allowing efficient transfer of magnetization to Pi. The advantage of wideband inversion is more evident at higher fields due to the increased PCr T1 value.  The single 31P inversion pulse necessary for this technique is easy to implement.

                    1237.   Quantitative Skeletal Muscle NMR Imaging of Juvenile Dermatomyositis Patients

                                Pierre G. Carlier1, Noura Azzabou1, Paulo Loureiro de Sousa1, Benoît Florkin2, Emmanuel Deprez3, Norma B. Romero4, Séverine Denis5, Valérie Decostre6, Laurent Servais7

                                1AIM-CEA Institut de Myologie, Laboratoire RMN, Paris, France; 2CHR La Citadelle, Service de Pédiatrie, Liège, Belgium; 3CHU de Liège, Service anatomie et cytologie pathologiques, Liège, Belgium; 4AIM, Institut de Myologie, Laboratoire d'histopathologie, Paris, France; 5Centre de référence des maladies neuromusculaires, CHR La Citadelle, Liège, Belgium; 6AIM, Institut de Myologie, Laboratoire de physiologie et d'évaluation neuromusculaire, Paris, France; 7AIM, Service Essais Cliniques et Bases de Données, Paris, France

 

The existence of oedematous/inflammatory/necrotic lesions is subjectively appreciated on T2-weighted images. Because it relies on identification of hyperintensities between and within muscles, the interpretation risk with T2-weighted images is to miss global, homogenous increases in T2. We demonstrate here this concern to be more than theoretical. Three patients aged 6, 7 and 12 were referred for suspicion of dermatomyositis. Standard T2w imaging was normal or subnormal. Quantitative T2 maps showed that muscle water T2s were abnormally elevated in the limb girdles and lower limbs. Quantitative T2 mapping can be required to detect unambiguously muscle lesions as here in juvenile dermatomyositis.

 

Traditional Poster

Spine

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1238.   Diffusion Tensor Imaging Detects the Spatial Variation in Fiber Angle and Lamellar Number in Intact Human Discs

                                Ron Noah Alkalay1, Dominik Meier2, Carl-Fredrik Westin, David B. Hackney3

                                1Orthopedics, Beth Israel Deaconess Medical Center, Boston, MA, United States; 2Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States; 3Radiology, Beth Israel Deaconess Medical Center, Boston, MA, United States

 

This study investigated the use of tensor diffusion imaging to directly interrogate the spatial orientation of collagen fibers’ in intact human disks.  Four human lumbar cadaver spinal discs (L2-L3), age 48-52 years, were imaged in a 9.4 Tesla scanner.  3D (SE-EPI) diffusion tensor image data was acquired using 30 non-collinear directions. Collagen fibers orientation angle relative to the disk’s axial plane was computed at each voxel.  DTI analysis showed clear demarcation between annulus and nucleus and the ability to count number of lamellae within the annulus. Analysis of fiber orientation showed fiber angle to increase as a function of region within the annulus.

                    1239.   Vertebral Fat Deposition with Normal Aging: Quantitative Analysis with IDEAL IQ at 3T

                                Yoshiko Hayashida1, Hodaka Oki1, Michiko Kobayashi1, Keita Watanabe1, Shingo Kakeda1, Takatoshi Aoki1, Yukunori Korogi1

                                1Radiology, University of Occupational and Environmental Health,Japan, Kitakyushu, Fukuoka, Japan

 

Purpose

Our purpose was to assess the fat fraction (FF) and R2* values (R2*) of the vertebrae in healthy subjects with IDEAL-IQ.

Materials and Methods

75 patients underwent MRI including IDEAL-IQ and the mean FF and the mean R2* within the spine were evaluated. ANCOVA was performed to investigate gender age and BMI group differences.

Results

FF increased with advancing age and interaction with gender. Young females showed a low FF. The group of low BMI showed a low FF.

Conclusion

The quantitative analysis of the vertebrae with IDEAL-IQ can demonstrate those age gender and BMI-related changes.

 

                    1240.   Interrelationships Between 3T-MRI-, 64-Section-MDCT-, and Micro-CT-Derived Trabecular Bone Structure Parameters: A Study in Cadavers

                                Miyuki Takasu1, Yoko Kaichi1, Chihiro Tani1, Shuji Date1, Yuji Akiyama1, Nobuhito Nango2, Kazuo Awai1

                                1Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan; 2Ratoc System Engineering, Tokyo, Japan

 

This study was performed to assess the relationship of 3T-MR- and MDCT-derived trabecular bone measurements with micro-CT measures as the gold-standard. L2 and L3 vertebral bodies of fresh human cadaver vertebrae were scanned. The under- and overestimation of parameters may be related to low spatial resolutions and susceptibility artifact. The MRI/MDCT-derived measurements correlated moderately with the gold-standards with the exception of Tb.Th. 3T MRI- and MDCT derived measures show significant correlations with micro-CT-derived parameters, suggesting that the two methodologies assess similar and complementary characteristics of bone.

                    1241.   Magnetic Resonance Evaluation of Multiple Myeloma at 3.0 Tesla: How Do Bone Marrow Plasma Cell Percentage and Selection of Protocols Affect Lesion Conspicuity?

                                Miyuki Takasu1, Yoko Kaichi1, Chihiro Tani1, Shuji Date1, Yuji Akiyama1, Yoshiaki Kuroda2, Akira Sakai3, Kazuo Awai1

                                1Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan; 2Hematology, Hiroshima University Hospital, Hiroshima, Japan; 3Radiation Life Sciences, Fukushima Medical University School of Medicine, Fukushima, Japan

 

The present study compared three fat-suppression techniques in terms of CNR and percent contrast and assessed the dependence of lesion conspicuity on BMPC% obtained from biopsy specimen. Significant negative correlations between percent contrast and CNR with BMPC% were demonstrated. We attributed this finding to increased signal intensity of background BM mainly caused by T2 prolongation by diffusely infiltrated myeloma cells, which can reduce the signal intensity contrast between focal lesion and background BM. In the low tumor load BM group, BM-focal lesion percent contrast was significantly greater for FS-T2 FSE than for the water image of IDEAL and STIR.

                    1242.   MRI Parameters as Predictive Factors of Adolescent Idiopathic Scoliosis Progression

                                Delphine Perie1, 2, Maxime Huber1, 2, Guillaume Gilbert3, Hubert Labelle2

                                1Mechanical Engineering, Ecole Polytechnique de Montréal, Montreal, QC, Canada; 2Research Center, CHU Sainte Justine, Montreal, QC, Canada; 3Philips Healthcare, Montreal, QC, Canada

 

Scoliosis deformities progress more during skeletal growth, producing asymmetric loading. But the remaining question is why does scoliosis progress in some people but either does not progress or spontaneously corrects itself in others? We performed the first multi-parametric MRI acquisition in vivo on eight patients with adolescent idiopathic scoliosis. The results validated our hypothesis: T1rho, T2, MTR, ADC and FA within the intervertebral disc are modified in a specific way during scoliosis progression. The possibility to predict the evolution of the disc degeneration will allow a better target of the surgical or orthopaedic treatment than what is done today.

                    1243.   Accurate Measurement of Intervertebral Disc Height Loss Demonstrates the Threshold of Major Pathological Changes During the Course of Degeneration

                                Joshua P. Jarman1, Dennis J. Maiman2, L.Tugan Muftuler3

                                1Medical college of Wisconsin, Milwaukee, WI, United States; 2Department of Neurosurgery, Medical college of Wisconsin, Milwaukee, WI, United States; 3Department of Neurosurgery and Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States

 

The etiology of intervertebral Disc (IVD) degeneration is still not completely understood. Degenerating discs begin to lose proteoglycans, which is a water retaining molecule. With the decrease in water, the discs lose their ability to resist compression and torque. Eventually the discs begin to lose height and structural integrity. The goal of this study was to quantify various pathological changes during the course of disc degeneration using MRI biomarkers. We proposed a method to quantify disc height loss with degeneration and suggested that the decrease in IVD height would correlate with other biomarkers of degeneration.

                    1244.   In Vivo  Magnetic Resonance Elastography of the Human Intervertebral Disk: Preliminary Results

                                Kaspar Josche Streitberger1, 2, Jing Guo3, Gerd Diederichs3, Sebastian Hirsch3, Andreas Fehlner3, Jürgen Braun4, Ingolf Sack3

                                1Department of Radiology, Charité - Universitätsmedizin Berlin , Berlin, Germany; 2Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany; 3Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany; 4Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany

 

The noninvasive detection and quantification of the human intervertebral disk by MR elastography (MRE) could be beneficial for the diagnosis of chronic disk degeneration. This study presents the first in vivo measurement of viscoelastic constants of the human intervertebral disc by MRE. Multifrequency MRE and multifrequency wave field inversion was applied to 15 healthy volunteers one of whom was measured 7 times on 7 different days. The magnitude of the complex shear modulus measured in the nucleus pulposus (mean value 4.34 ± 1.2 kPa) shows a good reproducibility and correlates with the MRI morphology based Pfirrmann score.

                    1245.   Detection of Extracellular Matrix Degradation in Intervertebral Disc Degeneration by Diffusion Magnetic Resonance Spectroscopy (DW-MRS)

                                Anna M. WANG1, 2, Adrian Tsang1, 2, Peng Cao1, 2, Danny Chan3, Ed X. Wu1, 2

                                1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong; 3Department of Biochemistry, The University of Hong Kong, Hong Kong

 

This study explored the capability of Diffusion Weighted Magnetic Resonance Spectroscopy (DW-MRS) to detect and characterize the ECM degradation during the early stage of IVDD. The apparent diffusion coefficient (ADC) of macromolecule resonances increased by approximately ten fold immediately after papain injection, and continued to increase in the following 5 days. The macromolecule T2 also had a slight increase during the ECM degradation and the macromolecule content is corrected by their corresponding T2 value. The macromolecule content, water T2 and ADC value showed a delayed change compared to the macromolecule ADCs. The macromolecule ADC is an early marker of the microstructural breakdown of PGs and collagen network in the disc NP during IVDD and hence DW-MRS is sensitive to detect disc degeneration at an early stage.

 

                    1246.   Intravoxel Incoherent Motion (IVIM) MR Imaging of Degenerated Intervertebral Lumbar Disks: An Initial Experience

                                Niu Gang1, Liu Zhe1, Du Yong Hao1, Yang Jian1, 2

                                1Department of Radiology, the first affiliated hospital of medical college, Xi¡¯an Jiaotong University, Xi'an, Shaanxi, China; 2Department of Biomedical Engineering, School of Life Science and Technology,  Xi' an Jiaotong University , Xi'an, Shaanxi, China

 

The aim of this study is to assess the feasibility of using intravoxel incoherent motion(IVIM) MRI in vivo to detect intervertebral disk degeneration(IVDD). 23 patients (14 men and 9 women; mean age 40 years; median age 47; age range 21~73 years) with low back pain or sciatica underwent IVIM MRI and T2 weighted images (T2WIs). It was showed that the pure diffusion ADClow of disk decrease with increased the Pfirrmann grades based on T2WI in this study, which indicated the decreased real diffusivity of free waterin IVDD. We also observed increased pseudodiffusion coefficient ADCfast values of AF with increased Pfirrmann grades,.The results demonstrated not only the significant differences in ADCfast of NP between grade I and IV, grade II and IV (ANOVA, P£¼0.05), but also the significant differences in ADCfast of AF between grade I and IV, II and IV, III and IV (ANOVA, P£¼0.05), which suggested an increasing microcapillary perfusionin IVDD. In sum, IVIM MR imaging may provide an objective and non-invasive biomarker for estimating diffusivity and microcapillary perfusion in IVDD.

                    1247.   T1ρ Imaging Demonstrates Inflammatory Changes in Disc Endplates That Were Not Visible in T1 or T2 Weighted Images

                                L.Tugan Muftuler1, Dhiraj Baruah2, Andrew Klein2

                                1Department of Neurosurgery and Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States; 2Department of Radiology, Medical college of Wisconsin, WI, United States

 

In some patients with low back pain, degenerative marrow changes are observed in the endplates around the degenerating intervertebral discs. These changes are classified based on the appearance of vertebrae in T1 and T2 weighted MRI. Type-1 changes usually involve early inflammatory changes and believed to play a role in pain generation. Type-2 changes generally involves conversion to fatty marrow. Although this classification is widely accepted, those images may not be sufficiently sensitive to early changes.  Increases in T1ρ relaxation rate were reported in regions of inflammation in animals. Therefore, we tested the efficacy of T1ρ imaging in endplate degeneration.

                    1248.   Feasibility of Detecting Spinal Instability in a Goat Spine Segment Using MR Elastography

                                Ephraim I. Ben-Abraham1, Jun Chen, Ph.D. 1, Richard L. Ehman, M.D. 1

                                1Radiology, Mayo Clinic, Rochester, MN, United States

 

Low back pain (LBP) is a very costly and prevalent health disorder in the U.S.  Spinal instability and degenerative disc disease are two of the most common causes of LBP.  It is known that the stiffness of the disc changes substantially with degeneration.  MRE has been demonstrated for estimating the shear stiffness of the nucleus in the intervertebral disc in vitro.  In this study, we attempt to measure spinal instability in an in vitro goat spine segment with induced disc degeneration and mechanical destabilization.  Our results suggest MRE may be capable of detecting spinal instability.

                    1249.   Pharmacokinetic Analysis of DCE-MRI Data from Lumbar Spine Reveals Pathologic Changes in Intervertebral Disc Endplates and Subchondral Bone

                                Volkan Emre Arpinar1, Dennis J. Maiman1, L Tugan Muftuler1, 2

                                1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; 2Center for Imaging Research, Medical College of Wisconsin, WI, United States

 

The majority of chronic back pain is associated with degeneration of the intervertebral discs. Despite comprehensive studies, there is no consensus on the mechanisms of pathological degeneration or how it should be distinguished from the normal aging processes. One of the causes of degeneration is believed to be poor nutrient transport to the disc through the endplates. In this study, Dynamic Contrast Enhanced MRI was used to investigate the relation between disc degeneration and aberrations in nutrient transport to the discs. A compartmental model with standard kinetic parameters was implemented to study perfusion in endplates and adjacent subchondral bones.

                    1250.   3D Model for MR Image Contrast in the Annulus Fibrosus of the Intervertebral Disc

                                Alexander C. Wright1, Edward J. Vresilovic2, Dawn M. Ellliott3

                                1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Department of Orthopaedics and Rehabilitation, Penn State University, Hershey, PA, United States; 3Department of Biomedical Engineering, University of Delaware, Newark, DE, United States

 

The purpose of this study is to provide a theoretical model for the visibility (image contrast) of collagen lamellae in the annulus fibrosus as seen in MRI. The model is based on the assumption of a dipolar term in the T2 relaxation mechanism of water protons and that the observed anisotropic modulation of signal intensity reflects the underlying microstructure of collagen fibers.

                    1251.   Prospective Study on Radiculopathy: Incremental Value of MR Neurography Over Non-Contributory Spine MRI

                                Avneesh Chhabra1, 2, Sahar Farahani2, Gaurav Thawait2, John A. Carrino2, Allan Belzberg3

                                1Radiology, UTSW, Dallas, TX, United States; 2Radiology, Johns Hopkins, Baltimore, MD, United States; 3Plastic surgery, Johns Hopkins, Baltimore, Ma, United States

 

MRI of lumbar spine is the current non-invasive imaging study of choice for bone and soft tissue evaluation. For suspected radiculopathy, therefore, it is reasonable to start with conventional MRI. However, MRI findings can be frequently non-contributary despite unilateral radiculopathy symptoms clinically, either due to not being able to reveal the problem or showing disc herniations at multiple levels. High resolution MR Neurography along with diffusion tensor imaging sequences can provide additional information in patients with radiculopathy. This prospective pilot study shows how more advanced pulse sequences could add new or different information compared to conventional MRI and explain the symptoms of radiculopathy.

                    1252.   MRI Signal Texture Parameters Within Human Intervertebral Discs as Biomarkers of Spine Pathologies and Severities

                                Delphine Perie1, 2, Clemence Balosetti1, 2, Sofiane Achiche1, Hubert Labelle2

                                1Mechanical Engineering, Ecole Polytechnique de Montréal, Montreal, QC, Canada; 2Research Center, CHU Sainte Justine, Montreal, QC, Canada

 

In both scoliosis and spondylolisthesis, the progression of the spine deformation leads to the degeneration of intervertebral discs characterized by a change in its structure and biochemical composition. The MRI images of 79 patients (32 with scoliosis, 32 with spondylolisthesis and 15 with herniated discs) were analysed using texture parameters extracted from the intensity histograms of the grey level, contrast, correlation, energy and homogeneity images. The results validated our hypothesis: the calculated tissue-specific texture features can effectively discriminate the pathologies and some of their severities. This method has the advantage of supporting the interesting possibility of developing robust non-invasive predictive methods for the diagnosis of the severities of spine pathologies.

                    1253.   The Relationship Between MRI and Histology in a Rat Model of Intervertebral Disc Degeneration

                                Jianming Hua1, Chengzhen Liang2, Risheng Yu1, Minming Zhang1

                                1Department of Radiology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; 2Department of Orthopedic Surgery, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China

 

To investigate a slowly progressive, reproducible rat model of disc degenerationsuitable for studying the participating mechanisms induced by needle puncture, and the relationship between MRI and histology in the long-term progression of disc degeneration.

                    1254.   The Perfusion Bias in Lumbar Vertibra by One Slice of DCE-MRI Measurement

                                Yi-Jui Liu1, Cheng Teng Chieh1, Yi-Hsiung Lee2, Wing P. Chan3

                                1Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan; 2Ph.D program in Electrical and Communication Engineering, Feng China University, Taichung, Taiwan; 3Department of Radiology, Taipei Medical University - Wan Fang Hospital, Taipei, Taiwan

 

Because of the inhomogeneous perfusion in vertebral body and only enrolled partial volume of vertebral body using one slice image, it is reasonable to make an assumption that the bias should be present in DCE-MRI examination. However, one slice DCE-MRI was usually performed in most research for temproal resolution. In this study, this hypothesis that blood perfusion is regional dependent in vertebral body was demonstrated using three middle sagittal, middle coronal and whole axial plane in thick axial slice data. The divergences of peak enhancement, wash-in and wash-out slope among three planes were investigated in 70 healthy vertebras.

 

Traditional Poster

MSK Misc.

Traditional Poster Hall     Monday 10:45-12:45                                                                     

                    1255.   Fat-Saturated T2-Weighted Imaging with Slice Encoding for Metal Artifact Correction (SEMAC) at 3T

                                Young Han Lee1, Jin-Suck Suh1, Eunju Kim2

                                1Radiology, Yonsei University College of Medicine, Seoul, 120-752, Korea; 2Philips Healthcare, Korea

 

Magnetic resonance (MR) imaging plays an important role in the postoperative evaluation of patients. Fluid sensitive fat-suppressed MR imaging is especially important in postoperative evaluation. However, metallic artifacts are inevitable with MR imaging, and these metallic artifacts are aggravated by using fat-saturation. We thought the combination of advanced metal-artifact-reducing MR technique and fat suppression would be useful in metallic MR imaging. Considering the advantages of 3T MR imaging of the spine such as an increase in SNR with optimized diagnostic quality and improved clinical impact, implementing fat-suppressed SEMAC-corrected at 3T MR is a major goal in metallic MR imaging.

                    1256.   Compressed Sensing Acceleration of Bone Imaging Using a 0.3 T Open Compact MRI for Skeletal Age Assessment

                                Yasuhiko Terada1, Daiki Tamada1, Tomomi Uchiumi1, Keiichiro Ishi1, Katsumi Kose1, Taiki Nozaki2, Yasuhito Kaneko2, Hiroshi Yoshioka2

                                1Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan; 2Department of Radiological Sciences, University of California Irvine, Orange, CA, United States

 

Skeletal age of a child can be evaluated by MR images of bones in the left hand. The hand imaging for young subjects often suffers from motion artifacts. Shortening the scan time provides an effective solution. Compressed sensing (CS) is a promising technique, but an image is not highly compressive when the signal-to-noise ratio (SNR) is low, and the CS application to bone imaging using a low-field MRI remains a challenge. Here we explore the possibility of CS-based acceleration of bone imaging with the 0.3T open compact pediatric hand scanner. We further show the validity of CS-based skeletal examination.

                    1257.   Magnetic Resonance Imaging Findings in a Dual Taper, Modular Total Hip Arthroplasty

                                Matthew F. Koff1, Stephanie L. Gold1, Brett Lurie1, Danyal H. Nawabi1, Geoffrey Westrich1, Hollis G. Potter1

                                1Hospital for Special Surgery, New York, NY, United States

 

Wear of at the neck-stem junction in modular total hip arthroplasty is associated with adverse local tissue reaction (ALTR) and premature implant failure. This study identified MR imaging findings characteristic of a failing modular THA system and determined which are most indicative of an ALTR, as confirmed by histology following revision arthroplasty. A majority (60%) of symptomatic hips had a moderate to severe ALTR. Synovial thickness was positively correlated with histologic scoring (ρ= 0.734, p<0.0003). Using MRI to measure synovial thickness may identify a premature failing hip and help guide surgical management in patients with ALTR.

                    1258.   Accelerated 3D RARE for Positional Weight-Bearing MRI of ACJ Bone Fixation with Metal Implants

                                Marco Vicari1, 2, Kaywan Izadpanah3, Andrea Serra4, Iulius Dragonu2, Guobin Li2, Maddalena Strumia, 25, Juergen Hennig2

                                1Esaote S.p.A., Freiburg, Germany; 2Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany; 3Dept. of Orthopedics and Trauma Surgery, University Medical Center Freiburg, Freiburg, Germany; 4Esaote S.p.A., Genoa, Italy; 5Deutsches Konsortium für translationale Krebsforschung (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany

 

An interesting clinical application of MRI near metal implants consists in checking the functionality of the acromio-clavicular joint of the shoulder after treatment by bone fixation with metal plates. The overall acquisition time is usually very long, since imaging at different abduction degrees of the shoulder is required, with a quite demanding spatial resolution to allow precise quantitative evaluations. Accelerated 3D RARE imaging for open-configuration, tilting MRI scanners at low-field well suits this clinical task, since it allows, within reasonable acquisition times, positional MRI under physiological weight-bearing with sensibly less metal-induced artifacts in comparison with high-field scanners.

                    1259.   High Resolution T-Mapping in Human Wrist Cartilage with a SAR and SENSE Optimized Coil at 7T

                                Mark W. J. M. Gosselink1, Joep van Oorschot1, Alexandra de Rotte1, Fredy Visser1, Peter R. Luijten1, Mies A. Korteweg2, Hanneke J. J. Bluemink1, Dennis W. J. Klomp1

                                1Radiology, UMC Utrecht, Utrecht, Netherlands; 2Radiology, AMC Amsterdam, Amsterdam, Noord-Holland, Netherlands

 

The classification of cartilage in the wrist by means of TMRI requires ultra-high spatial resolutions. While Tsequences coincide with long and strong B1+ fields, we demonstrate that a SAR optimized coil can provide uncompromised TMRI of the wrist even at 7T. Demonstrated with strong and uniform spin locking fields, combined with 32 channel receivers, quantified 0.5 mm isotropic Tare obtained of cartilage in the wrist.

                    1260.   Serial Observations and Correlation of Combined Sacroiliitis and Apophyseal Joint Inflammation in Patients with Enthesitis Related Arthritis.

                                Tom Amies1, Kanimozhi Vendhan1, Debajit Sen2, Corrine Fisher2, Yiannis Ioannou2, Paul Humphries1, Margaret Hall-craggs1

                                1Radiology, University College Hospital, London, United Kingdom; 2Rheumatology, University College Hospital, London, United Kingdom

 

Enthesitis related arthritis (ERA) is a form of juvenile arthritis which presents with a varying degree of apophyseal joint inflammation and/or sacroiliitis. We present a retrospective review of serial MRI scans correlating the changes in apophyseal joint inflammation and sacroiliitis. Images were reviewed independently by two expert MR readers using a global visual assessment and a numerical scoring method. We correlated these findings with the therapeutics the patients were receiving at the time of the scans. We have found that concurrent sacroiliitis and apophyseal joint synovitis in patients with ERA can respond independently of one another whilst on conventional therapy.

                    1261.   Improved Delineation of Blood Vessels in Fingers with High-Resolution Non-Contrast-Enhanced Time-Of-Flight MR Angiography

                                Wingchi Edmund Kwok1, 2, Zhigang You1, Christopher Ritchlin3

                                1Department of Imaging Sciences, University of Rochester, Rochester, NY, United States; 2Rochester Center for Brain Imaging, University of Rochester, Rochester, NY, United States; 3Department of Medicine, University of Rochester, Rochester, NY, United States

 

With the use of a dedicated RF coil and a modified pulse sequence at 3T, we conducted high-resolution non-contrast-enhanced time-of-flight MR angiography of fingers on two normal subjects, and compared the results with data acquired using the highest resolution we found in finger MRA studies by other groups.  Our higher-resolution images give sharper and more definitive depiction of the blood vessels, enabling better visualization of the geometry and connectivity of the blood vessels as well as the relationship between the vessels.  Our technique should be useful for the diagnosis, treatment assessment and pathogenesis studies of arthritis and systemic sclerosis.

                    1262.   Feasibility of Hip Prosthesis Imaging at 3T

                                Chen Lin1, Kecheng Liu2, Bruce Spottiswoode2, Kenneth Buckwalter1

                                1Radiology and Imaging Science, IU School of Medicine, Indianapolis, IN, United States; 2Siemens Medical Solutions, USA Inc., PA, United States

 

MRI of patients with hip prostheses remains a challenge, particularly at 3T. Through phantom and volunteer studies, a set of optimized protocols for metal artifact reduction (MAR) using view angle tilting (VAT) and slice encoding metal artifact correction (SEMAC) was found to produce diagnostic information within a clinically acceptable scan time at 3T. For prostheses made of non-magnetic alloys, the degree of MAR approaches that of 1.5T.

 

                    1263.   Changes in Muscle Mitochondrial Energetics In Vivo and Physical Fitness in Operable Rectal Cancer Patients Following Neoadjuvant Chemoradiotherapy – an Observational Pilot Study

                                Malcolm A. West1, Lisa Loughney2, Michael PW Grocott3, Sandy Jack3, Graham J. Kemp1

                                1Magnetic Resonance and Image Analysis Research Centre, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, Merseyside, United Kingdom; 2Critical Care Research Area, NIHR Respiratory BRU, University Hospital Southampton, Southampton, Hampshire, United Kingdom; 3Integrative Physiology and Critical Illness Group, Faculty of Medicine, University of Southampton, Hampshire, United Kingdom

 

This prospective study of 12 locally advanced rectal cancer patients aims to investigate the effects of standardised neoadjuvant chemoradiotherapy (NACRT) on objectively measured mitochondrial energetics and physical fitness using 31-phosphorus magnetic resonance spectroscopy (31P MRS) and cardiopulmonary exercise testing (CPET). A significant reduction in oxygen uptake at estimated lactate threshold, oxygen uptake at Peak exercise (ml.kg-1.min-1), and a parallel decrease in post-exercise phosphocreatine (PCr) recovery rate constant (kPCr min-1 suggests that mitochondrial mechanisms are important in the loss of fitness induced by NACRT.

                    1264.   Low Field MRI for the Detection of Acute Knee Injuries Shows Good Diagnostic Accuracy and Interobserver Agreement

                                Jonas Bürk1, Philippe Dovi-Akue1, Matthias Benndorf1, Benjamin Fritz1, Philipp Lenz1, Tobias Baumann1

                                1Radiology, Universitiy Hospital Freiburg, Freiburg, Baden Württemberg, Germany

 

In comparison to high field MR-scanners, the main disadvantages of low field MR-scanners are reduced signal-to-noise Ratio (SNR) and resolution in comparison with higher magnetic field strength. Despite these limitations, several publications which compared low field MRI to arthroscopy showed good sensitivity and specificity for the detection of cruciate ligament ruptures and meniscus lesions. Since there are no publications using low field MR-scanners of the newest generation so far, the objective of this study was to analyze the capabilities of low field MR-scanner of the newest generation in the detection of musculoskeletal knee injuries of acute trauma patients in comparison to the gold standard (arthroscopy and CT). In our study we observed very good sensitivity and specificity in the diagnosis of traumatic meniscal tears, ACL tears as well as fractures with low field MRI. Advantages of low field MRI are the reduced costs for purchasing and maintenance. It follows that high patient throughput based on economic pressure is not necessary, allowing to keep examination slots free for acute trauma patients.

                    1265.   Magic Angle Enhanced MR Microscopy of Fibrous  Structures in Normotensive and Hypertensive Eyes Using T2, T2* and T1rho MRI

                                Leon C. Ho1, 2, Ian A. Sigal3, Ning-Juan Jan3, Hunter Mehrens1, Alexander Squires4, Zion Tse4, Ed X. Wu2, Joel S. Schuman3, Seong-Gi Kim1, 5, Tao Jin1, Kevin C. Chan1, 3

ISMRM_MagnaLogo.jpg                                 1Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China; 3Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; 4Medical Robotics Lab, College of Engineering, The University of Georgia, Athens, GA, United States; 5Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Dept. of Biological Sci, SKKU, Suwon, Korea

 

Sclera is a fibrous connective tissue in the outer coat of the eye which may undergo microscopic structural reorganization under different physiological environments. Ocular hypertension may apply tensile stress to sclera leading to microstructural changes. However, there are limited non-invasive technique available. In this study, we demonstrated the feasibility of using magic angle enhanced MRI in different MR contrasts to detect magnetic tissue property changes in scleral fibers of and normotensive and hypertenive eyes.

 

                    1266.   Automated Analysis of Three-Dimensional Mandibular Movement Using Multi-Section Dynamic MRI

                                Ryusuke Nakai1, Takashi Azuma2, Keiji Shigeno1, Mariko Wakatsuki1, Guoxiang Liu2, Osamu Takizawa3, Hiroo Iwata4

                                1Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan; 2Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan; 3Siemens Japan K.K., Tokyo, Japan; 4Institute for Frontier Medical Sciences, Kyoto University, N/A, Kyoto, Japan

 

In the current study, a technique was developed for continuous time-series mandibular imaging of multiple sections with analysis of time-series data and automatic measurement of the three-dimensional positions and rotation angles of the mandibular movement. The utility of this technique was evaluated by analysis of mandibular movement in volunteers. As a result, the automatic measurement technique had very good precision. This technique gives precise information that can facilitate diagnosis of temporomandibular joint disorder and mandibular movement disturbance. Therefore, this technique should permit rapid diagnosis of symptoms and disorders by dentists.

                    1267.   Sparse Dynamic MRI of the Temporomandibular Joint

                                Stefan Wundrak1, Jan Paul1, Johannes Ulrici2, Erich Hell2, Volker Rasche1

                                1Ulm University Hospital, Ulm, Germany; 2Sirona Dental Systems, Bensheim, Germany

 

Assessment of the masticatory motion of the temporomandibular joint (TMJ) is of interest for a variety of pathologies, e.g. the abnormal motion of the articular disc. In this contribution we use k-t radial sparse SENSE for the imaging of the TMJ dynamics to increase the achievable spatiotemporal resolution. While previous methods enabled dynamic TMJ imaging without motion blur at 15 to 50 seconds per opening-closing cycle, the proposed methods enables the imaging of the TMJ at opening-closing cycle times of 4 to 8 seconds.

                    1268.   Scan Time Acceleration by Using Multi-Contrast Keyhole Imaging (McK) for the Identification of (Acute) Apical Periodontitis

                                Anna-Katinka Bracher1, Volker Rasche1, Erich Hell2, Johannes Ulrici2, Axel Bornstedt1

                                1Internal Medicine II, University Hospital  of Ulm, Ulm, BW, Germany; 2Sirona Dental Systems, Bensheim, HE, Germany

 

The diagnosis of apical periodontitis and the differentiation between acute and chronic lesions with MRI requires images of identical anatomy with different contrasts (T1w and T2w). A reduction of examination time can be obtained by sharing the information of high frequency components of k-space. Using the information of an high resolution reference scan (T1w) a high resolution multi contrast image of a low-resolution T2w scan of the same anatomy can be provided.

                    1269.   Imaging of the Moving Wrist Using Rapid Undersampled K-Space Acquisition with Iterative Reconstruction

                                Michael H. Buonocore1, Robert D. Boutin1, Igor Immerman2, Abhijit J. Chaudhari1

                                1Radiology, UC Davis, Sacramento, CA, United States; 2Orthopedic Surgery, UC Davis, Sacramento, CA, United States

 

This abstract describes the use of undersampled cartesian and radial k-space acquisition, combined with iterative, cost-function based image reconstruction for rapid real-time imaging of the moving wrist. The techniques provide sufficient image quality for observation and quantitative measurement of changing carpal bone angles and distances during the motion, and spatial and temporal resolution of the image set can be flexibly traded-off as part of reconstruction after the k-space data has been collected. These measurements are important for assessment of carpal bone instability, tendon dislocation, and other pathologies of wrist joint action.

                    1270.   Magnetic Resonance Arthrographic Visualization of Surgical Classification of Rotator Cuff Tear

                                Young Han Lee1, Jin-Suck Suh1, InSeong Kim2

                                1Radiology, Yonsei University College of Medicine, Seoul, 120-752, Korea; 2Siemens Healthcare, Korea

 

Classification of RCT using shoulder MR imaging is traditionally based on tear width and thickness, not arthroscopic classification. However, for surgical RCT repair, arthroscopic classification is more useful because the surgical method depends on the classification type. For example, U-shaped tears can be repaired by margin convergence whereas crescent-shaped tears can be repaired directly by a tendon-to-bone technique. We believe the ability to determine surgical classification of RCT type with preoperative MR imaging could be helpful, especially with recently introduced three-dimensional (3D) MR sequences.

                    1271.   A Novel Method for Quantifying Inflammation of Sacroiliitis in Juvenile Arthritis

                                Kanimozhi Vendhan1, David Atkinson2, Debajit Sen1, Corinne Fisher1, Yiannis Ioannou3, Paul Bassett4, Margaret Hall-Craggs5

                                1UCLH, London, United Kingdom; 2UCL, London, United Kingdom; 3Arthritis Research UK Centre for Adolescent Rheumatology, UCL, London, United Kingdom; 4Statsconsultancy Ltd, London, United Kingdom; 5Imaging Department, UCLH, London, United Kingdom

 

This was a retrospective case-control study to quantify sacroiliitis in patients with juvenile arthritis by using ADC maps. Along with conventional sequences, DWI of the sacroiliac joints (SIJs) was performed at multiple b values. A Matlab program was written to create a profile of ADC values across the SIJs and a reference sample in normal bone. This was done by manually drawing a multiple linear regions of interest, centered on the SIJ. There was a highly significant difference between the ADC area scores of the cases and controls.  This novel technique for quantifying sacroiliitis could potentially be used to monitor response to therapy.

 

                    1272.   Three-Dimensional Morphological Features for Detection of Degeneration in the PCL from Magnetic Resonance Images at 3T: A Feasibility Study

                                Katharine J. Wilson1, Jurgen Fripp2, Kaikai Shen2, Rachel K. Surowiec1, Charles P. Ho1

                                1Steadman Philippon Research Institute, Vail, CO, United States; 2CSIRO Computational Informatics, The Australian eHealth Research Centre, Queensland, Australia

 

Chronic posterior cruciate ligament (PCL) injuries are often affected by degeneration with symptoms including thickening and elongation of the ligament. Conventional diagnosis with MRI has proven variable therefore the ability to quantify the shape of the ligament may prove valuable. The purpose of the study was to characterize the normal shape variations in an asymptomatic population of PCLs using statistical shape models (SSM) derived from MRI. We observed a significant difference in absolute volumes between age and gender groups and present the anatomical variability in a cohort of 27 asymptomatic PCLs analyzed using SSM.

                    1273.   3D Thickness Maps Derived from Automated Segmentation of Knee Articular Cartilage at 1.5T; a Feasibility Study Using 3D FS DESS, 3D PD FS FSE and 2D PD FS FSE

                                Joshua Michael Farber1, Saara Totterman2, Jose Tamez-Pena3, Edward Schreyer2, Karl Baum2

                                1Radiology, Qmetrics Technologies, Cincinnati, OH, United States; 2Radiology, Qmetrics Technologies, Rochester, NY, United States; 3Bio Sciences, Tec De Monterry, Monterry, Mexico

 

OA repair techniques are becoming ubiquitous, inlcuding autograft and allograft repairs. This material explores the feasibility of using routine 3D FS DESS, 3D PD FS FSE and 2D PD FS FSE at 1.5 T to generate 3D articular cartilage (AC) thickness maps with an atlas based, voxel by voxel automated segmentation platform.

                    1274.   Fast Interactive Segmentation of Skeletal Muscles in MRI

                                Alexey Shukelovich1, 2, Pierre-Yves Baudin1, Noura Azzabou1, Pierre G. Carlier1, Jean-Marc Boisserie1, Julien LeLouer1

                                1AIM-CEA Institut de Myologie, Laboratoire RMN, Paris, France; 2The United Institute of Informatics Problems of the National Academy of Sciences of Belarus, Minsk, Belarus

 

In this work we present a user-friendly interactive segmentation tool that is handy and suitable for clinicians and is developed to

 

improve, accelerate and facilitate MRI muscle segmentation process. Segmentation software is built on the top of ITK-SNAP and

 

incorporates a new segmentation tool based on a robust semi-automatic random walker algorithm. Experimental segmentation was done on a

 

human thigh muscle MRI dataset and compared to a manual segmentation using relative volume differences and Dice coefficients. We have

 

achieved a sufficient acceleration in segmentation process with minor loss of segmentation quality.

                    1275.   Effect of Dilution of Different Gadolinium Agents on Signal Intensity at 1.5 Tesla: Implications for Direct MR Arthrography

                                Roula Bou Sader1, William B. Morrison2, Alex Dresner2, Luke Maj2, Yulia Gombar2, Adam Zoga2

                                1Radiology, Thomas Jefferson University Hospital, Philadelphia, PA, United States; 2Thomas Jefferson University Hospital, PA, United States

 

We sought to optimize direct MR arthrography by determining the optimal concentration of three contrast agents. Magnevist, Gadavist and Optimark dilutions were scanned at 1.0, 1.5T, and 3.0T. On T1-SE, all contrast agents tested showed peak signal at a dilution of 2.0-2.6 mmol/L. On FSE-PD and T2, signal decreased rapidly with increasing concentrations. On 2D-GRE, there was less variation in signal intensity, with a peak at 2.0 mmol/L for each contrast agent. On STIR imaging two peaks were observed, one at the minimum concentration and another at 4.0 mmol/L. There was very little difference between contrast agents tested.

Traditional Poster

MR Engineering:  RF & Other

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1276.   A Wireless Digital Capacitor Module for Tuning Receive Coil Arrays

                                Arne Reykowski1, Randy Duensing1

                                1Invivo Corporation, Gainesville, FL, United States

 

This paper presents a novel approach for tuning RX coil arrays using wireless digital programmable capacitors. This hardware is intended for research to improve coil tuning strategies and improve combined SNR beyond the currently accepted limits. The ability to change tune settings in the absence of a cable connection or the need to touch the hardware should greatly improve the accuracy of repeated SNR measurements.

                    1277.   Optical Power Transmission Can Help to Build Receive Coils Without Coaxial Cables

                                Jens Höfflin1, Elmar Fischer2, Oliver Gruschke1, Jürgen Hennig2, Jan G. Korvink1, 3

                                1Lab of Simulation - Department of Microsystems Engineering, University of Freiburg - IMTEK, Freiburg, Germany; 2Medical Physics - Department of Radiology, University Medical Center Freiburg, Freiburg, Germany; 3Freiburg Institute for Advanced Studies - FRIAS, University of Freiburg, Freiburg, Germany

 

We present the use of optical power transmission as a possibility to power electronic components like an LNA inside the magnet without needing to use copper cables. The use of switching DC-to-DC converters inside high magnetic fields is evaluated, and SNR measurements are presented to compare the performance of different receive coil setups.

                    1278.   23Na Magnetic Resonance Spectroscopic Imaging (MRSI) on a High-Density 3d-Cell Culture on Chip (3D-KITChip)

                                Andreas Neubauer1, Michaela Ruttorf1, Raffi Kalaycian1, Jan Sachs1, Cordula Nies2, Stefan Giselbrecht2, Eric Gottwald2, Lothar Schad1

                                1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Baden-Wuertemberg, Germany; 2Institute for Biological Interfaces-1, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Baden-Wuertemberg, Germany

 

In this study we present a setup capable to monitor changes in ionic concentration gradients in vitro. The main parts of the setup are a three dimensional cell culture, a completely MR-compatible bioreactor and a 23Na surface coil. In a pilot study we performd a 23Na CSI experiment to show that we are able to resolve a non varying reference compartment from a compartment with varying physiological parameters.

                    1279.   Harnessing Embedded Linux and Python for Stand-Alone MRI Applications

                                Pascal P. Stang1, 2, Greig Scott2

                                1Procyon Engineering, San Jose, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States

 

Advances in RF electronics, high-speed data converters, and multi-core processors have long fueled high-end MRI techniques such as parallel imaging and real-time scanning, yet these same technology advances can also be leveraged to benefit small-scale MR. We present a compact stand-alone MRI console powered by embedded Linux and programmed in Python to investigate the potential of such a platform to deliver modern performance and versatility for NMR/MRI applications constrained in size, power, cost, or user interface.  Potential applications include desktop scanners, chemical spectroscopy and relaxometery, RF ablation control, and interventional device safety monitoring.

                    1280.   Web-Interactive Sharing of Medical Images and Processing Algorithms: The WISDM Framework

                                Jeremy F. Magland1, Felix W. Wehrli1

                                1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

 

WISDM is an open source software allowing web browser-based sharing of medical imaging data stored on any internet-connected computer. Users may interactively browse raw, intermediate, and resulting image arrays. In addition, processing algorithms written in a variety of scripting languages (MATLAB/Octave, C/C++, and Python) may be browsed on-line, and even edited and executed by authorized users. The framework has been used within the authors' institution to manage imaging data and processing pipelines for two imaging laboratories and allows multiple researchers to process and

interact with a common pool of data from any operating system without downloading datasets or installing software.

 

                    1281.   BirdcageBuilder Mobile: New Functionality and Portability for a Standard MR Engineering Tool

                                Giuseppe Carluccio1, Chih-Liang Chin2, Christopher Michael Collins1

                                1Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, United States; 2Merck Sharp & Dohme, Singapore, Singapore

 

Birdcage coils are the most commonly used-volume coils in MRI for their ability to provide homogeneous circularly polarized fields inside their volume with a quadrature channel excitation. One of the most used tools by RF coils designers is BirdcageBuilder, a software which provides the values of the capacitors needed to make the coil able to resonate. In this work we extend the functionality and portability of the software by designing a version which can run on common mobile devices for easy access anywhere coils are constructed, and provide all resonant frequencies of the coil as designed.

                    1282.   Actively Shielded Bias Magnetic Field Tuning Coil for Optically Pumped Atomic Magnetometer Toward Direct MR Signal Detection in Ultra-Low Field MRI

                                Takenori Oida1, Masahiro Tsuchida1, Tetsuo Kobayashi1

                                1Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan

 

Recently, optically pumped atomic magnetometers (OPAMs) have been developed and allow us easily to measure extremely small magnetic fields. An ultra-low field (ULF) MRI system with an OPAM has been attracted attentions in recent years. In this study, we proposed an actively shielded bias magnetic field tuning coil toward direct detection of MR signals with an OPAM. Results of magnetic field distribution analyses demonstrated that the active shield could reduce the magnetic distortion caused by the bias tuning coil and the actively shielded bias magnetic field tuning coil was feasible to detect MR signals directly with an OPAM.

                    1283.   Very Low Field Imaging of Laser-Polarized Noble Gases

                                Yuan Zheng1, Gordon D. Cates2, John P. Mugler2, William A. Tobias2, G Wilson Miller2

                                1University of Virginia, Charlottesville, VA, United States; 2University of Virginia, VA, United States

 

We built an inexpensive low field MRI system and implemented a novel design of transverse gradient coils. We presented images of hyper-polarized He-3 and Xe-129 phantoms. Our system can also be expanded for small animal and even human lung imaging.

                    1284.   Phase Coherent Multi-Channel Synthesizer of Transmit Pulses at Larmor Frequencies Up to 512 MHz

                                Andrzej Jesmanowicz1

                                1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

 

The method of multi-channel RF pulse creation is presented here by the use of a set of independent wave-form synthesizers.  They can operate directrly at Larmor frequency as high as 512 MHz.  Up to 16 channels with absolute phase coherency can supply pulses to transmit amplifiers of scanners operating at magnetic fields up to 12 Tesla.

                    1285.   Comparison of Analog and Digital Transceiver Systems for Magnetic Resonance Imaging

                                Seitaro Hashimoto1, Katsumi Kose1, Tomoyuki Haishi2

                                1University of Tsukuba, Tsukuba, Ibaraki, Japan; 2MRTechnology Inc., Tsukuba, Ibaraki, Japan

 

Analog and digital transceivers for MRI systems were critically evaluated under identical experimental conditions. The MRI experiments were performed using a 4.74-Tesla vertical-bore superconducting magnet and a high-sensitivity gradient coil probe. 3D spin-echo images of a kumquat were acquired with and without using a gain-stepping scan technique to extend the dynamic range of the receiver systems. The acquired MR images clearly demonstrated that nearly identical image quality was obtained for both transceiver systems, but DC and ghosting artifacts were obtained for the analog transceiver. We therefore concluded that digital transceivers have several advantages over the analog transceivers.

                    1286.   A Generalized Concept for Preamplifier Decoupling

                                Enrico Pannicke1, 2, Roland Müller2, Oliver Speck3, Ralf Vick1, Harald E. Möller2

                                1Institute for Medical Engineering, Otto-von-Guericke-University Magdeburg, Magdeburg, Saxony-Anhalt, Germany; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Saxony, Germany; 3Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Saxony-Anhalt, Germany

 

Preamplifier decoupling is a valuable technique in the development of multi-channel receiver array coils. Although well established, there is currently no simple rule available to design a proper network with desired properties. A suitable equation can be derived utilizing the concept of impedance transformations. With this concept, the robustness of the coil against varying loading conditions of the coil was investigated as a further property of the circuit.

                    1287.   Near-Magnet Power Amplifier with Built-In Coil Current Sensing

                                Klaus Solbach1, Ashraf Abuelhaija1, Samaneh Shooshtary1

                                1RF Technology, University Duisburg-Essen, Duisburg, Germany

 

A new concept of a near-magnet PA is presented which operates without circulator/isolator but closely cooperates with the coil to allow control of the coil current.  The concept features a voltage probe at the PA output and a tuned transmission line connecting the coil. The probe voltage is proportional to the coil current which allows control of the coil current under mismatch and mutual coupling from other coils in an pTx array without extra pick-up loop. The function is demonstrated by an experimental set-up creating a wide range of load impedance by varying the coil distance to a phantom.

                    1288.   Stability Test of Near-Magnet Power Amplifier

                                Kabir Hasanzadeh1, Klaus Solbach1, Samaneh Shooshtary1

                                1RF Engineering, University Duisburg-Essen, Duisburg, NRW, Germany

 

In this work a method to test the Stability of Near-Magnet Power Amplifier (DUT) is explained and the test results are presented. The method includes a bench stability test which employs an electronic circuit designed to realize reflection coefficients with variable magnitude and phase, which is implemented using the concept of the laod-pull. The  mutual effect between the antennas around the coil have also been tested to confirm the stability of the DUT in such situations. Results show that although the DUT is stable for all the situations, but the output power is depended on the variation of the load.

                    1289.   Sensing of Birdcage Rung Currents for Detection of Anomalous Loading

                                Christopher Ellenor1, Pascal Stang, 12, John Pauly1, Greig Scott1

                                1Electrical Engineering, Stanford University, Stanford, CA, United States; 2Procyon Engineering, San Jose, CA, United States

 

A birdcage coil is fitted with optically coupled current sensors on each of its rungs.  This tool gives new, rapid and realtime information about the spatial distribution of current in the coil under different loading conditions.  The detection of anomalous loading conditions may be indicative of certain RF safety hazards such as resonant wire coupling or strong coupling to tissue through the bore wall, leading to burns. Phantom experiments are conducted and distortion of the rung current pattern due to anomalous loading is observed.

                    1290.   Modeling PIN Diode Temperature Rise in High Induced Current MR Receive Coils

                                Robert Caverly1, Ronald Watkins2, William E. Doherty3

                                1Villanova University, Villanova, PA, United States; 2Department of Radiology, Stanford University, Stanford, CA, United States; 3Microsemi, Lowell, MA, United States

 

A new electrothermal SPICE-based model that predicts both electrical and thermal behavior of PIN diodes used in high field, high power MR imaging is described.  The model accurately predicts the temperature rise in blocking applications and is fully compatible with industry-standard simulators such as SPICE as well as it variants.  Knowledge of the temperature rise in PIN protection diodes is important because failure rates of these devices dramatically increase if temperatures exceed approximately 150 oC, with a potential loss of patient and equipment protection

                    1291.   14T Dual-Tuned RF Probes for 13C/1H MRI Using Common-Mode Differential-Mode (CMDM) Method

                                Hong Shang1, Xiaoliang Zhang1, 2, Yiran Chen1, Subramaniam Sukumar1, Peder Larson1, Daniel B. Vigneron1, 2, Duan Xu1, 2

                                1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States; 2UC Berkeley/UCSF Joint Bioengineering Program, San Francisco, CA, United States

 

Double-tuned radiofrequency (RF) coils are critical for multinuclear MR applications, with advantage of image co-registration of proton anatomic images and multinuclear metabolic images, and B0 shimming using proton channel for low natural abundance heteronuclear MRSI. In this work, a 14T double-tuned surface coil was built based on the CMDM method, which has been proposed for designing double-tuned RF coils with better decoupling between channels and was demonstrated to provide excellent performance and easy implementation at 7T. Bench tests and phantom imaging were performed and demonstrated excellent decoupling between the two channels, efficient impedance match, and independent tuning.

 

                    1292.   Independent Active Decoupling Circuit for RX Coil on MR Systems Without Active Decoupling Capabilities (0.2T) or with Connecting Issues (3T).

                                Thomas Feuillet1, 2, Herve Saint-Jalmes3, 4, Marie-Jose Seurin2, Michele Zani5, Alejandro Bordelois6, Olivier Beuf1

                                1Université de Lyon, CREATIS ; CNRS UMR 5220 ; INSERM U1044 ; INSA-Lyon ; Université Lyon 1, Villeurbanne, France; 2SARL Cirma, Marcy l'Etoile, France; 3LTSI ; INSERM U1099, Université Rennes 1, Rennes, France; 4CRLCC, Centre Eugene Marquis, Rennes, France; 5Agilent Technologies, Oxford, United Kingdom; 6CBM, Universidad de Oriente, Santiago, Cuba

 

Some MR systems do not provide an active decoupling bias signal to RX coil and use only passive and/or geometrical decoupling. An external circuit which independently generates an active decoupling signal for RX coils for any MR system was developed. The circuit was tested on a 0.2T system with no active decoupling, and at 3T to demonstrate its interest when an additional dedicated RX coil is designed and its connection is unknown or third part coil is not allowed. Results were considered at both fields and were comparable to reference decoupling methods, in terms of delays, SNR and B1 uniformity.

                    1293.   Design of Flanged RF Shield for Mitigation of RF and Gradient Coil Interactions

                                Muhammad Hassan Chishti1, Jean-Baptiste Mathieu1, Joseph E. Piel1, Desmond T.B. Yeo1, Christopher J. Hardy1, Dominic Graziani1, Seung-Kyun Lee1

                                1GE Global Research Center, Niskayuna, NY, United States

 

Radio-frequency (RF) shields mitigate undesired interactions between gradient coils and RF transmit coils. RF losses in gradient windings can lower the Q of the RF coil and result in increased power requirements. In this work, we present full-wave electromagnetic modeling and analysis of an end-flanged shield for use with an asymmetric head gradient coil. Differences in B1 maps with and without the flanged shield indicate that flanged shield is effective in ameliorating RF field leakage to the gradient coils. Bench measurements also show that Q of the RF coil improved from 50 (without flanged shield) to 185 (with flanged shield).

                    1294.   Regional Faraday Shielding for Improved Dynamic Hyperpolarized 13C MRI

                                Cornelius von Morze1, Galen D. Reed1, Hong Shang1, Hsin-Yu Chen1, Lucas Carvajal1, James Tropp2, Daniel B. Vigneron1, Peder EZ Larson1

                                1Dept. of Radiology & Biomedical Imaging, UCSF, San Francisco, CA, United States; 2GE Healthcare, Fremont, CA, United States

 

We investigated the use of regional Faraday shielding to help prevent loss of hyperpolarized 13C magnetization due to premature excitation during tracer delivery and recirculation about a primary region of interest. The value of this approach was demonstrated in simulations and hyperpolarized phantom experiments.

                    1295.   Cross-Validation of Magnetic Resonance Elastography by Continuous Acoustic Vibration and Ultrasound Elastography by Acoustic Radiation Force Impulse: A Phantom Study

                                Mikio Suga1, 2, Riwa Kishimoto2, Atsuhisa Koyama1, Tetsuya Wakayama3, Takayuki Obata2, Hiroshi Tsuji2

                                1Chiba University, Chiba, Japan; 2National Institute of Radiological Sciences, Chiba, Japan; 3GE Healthcare Japan, Tokyo, Japan

 

For noninvasive evaluation of biomedical tissue elasticity, magnetic resonance elastography (MRE) and ultrasound elastography (USE) using acoustic radiation force impulse (ARFI) have become common for use in clinical practice. However, USE-ARFI has not yet been compared with MRE. In this study, the quantitativity of MRE and USE-ARFI (VTTQ) measurement was evaluated by polyacrylamide phantoms. There was strong correlation between MRE and rheometer, and VTTQ and rheometer. VTTQ with 4 MHz convex probe showed higher standard deviation, and VTTQ and MRE showed different depth dependency. Therefore, we should consider of the properties of each method.

                    1296.   Construction and Use of a Micro Resolution Phantom for Small Bore MRI

                                Samuel Barnes1, Naomi Santa Maria1, Russell Jacobs1

                                1Biology, Caltech, Pasadena, CA, United States

 

Despite their usefulness in quality assurance of high resolution small bore systems, resolution phantoms with feature sizes of 100um are not commercially available. This works describes the design, manufacture, and use of resolution phantoms with features in the 100um to 500um range. These can be easily designed using CAD software and manufactured using laser drilling techniques. This provides a custom cost effective solution for labs to perform testing on new or existing sequences.

                    1297.   A Resistive Heating System for Homeothermic Maintenance in Small Animals.

                                Stuart Gilchrist1, Philip D. Allen1, John S. Beech1, Veerle Kersemans1, Paul Kinchesh1, Boris Vojnovic1, Sean C. Smart1

                                1Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, United Kingdom

 

Anaesthesia is usually required for the immobilisation of animals for imaging. This induces a heat loss that must be artificially offset. It is commonplace for warm fluids (piped liquids or circulating air) to be used to provide this heat but these systems require significant space in which to circulate. We demonstrate a resistive heating system that creates no discernible artefacts in MR images or spectroscopy, and which requires no additional space as it embedded within the animal support cradle.

 

                    1298.   Development of an MRI Method for Awake Mouse Imaging Using Soft Immobilization and a Fast MR Acquisition Procedure

                                Shunsuke Kusanagi1, Kazunari Kimura2, Makoto Hirakane2, Shigeto Iwamoto2, Rikita Araki3, Sosuke Yoshinaga2, Hiroaki Terasawa2

                                1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan; 2Faculty of Life Sciences, Kumamoto University, N/A, Kumamoto, Japan; 3Bruker Biospin K.K., Yokohama, Kanagawa, Japan

 

Mouse MRI studies facilitate the elucidation of the pathogenic mechanisms underlying various diseases and the appropriate medical treatments, due to the remarkable advances in mouse genetic technology.  It is difficult to acquire accurate MR images when an imaging target moves in the scanner, and thus treatment with anesthesia and fixing apparatuses are usually required.  However, the brain activation profiles were reportedly affected by anesthesia.  To exclude the unfavorable anesthetic effects, we successfully developed an easy-to-operate method for awake mouse brain imaging, which uses softer immobilization with clothes for mice and a fast MR acquisition procedure, without surgery and training.

                    1299.   Noncontact Physiological Measurements Using Video Recording Inside an MRI Scanner

                                Shang-Yi Yang1, Hsaio-Hui Huang1, Chi-Wei Liang1, Shang-Yueh Tsai2, Teng-Yi Huang1

                                1National Taiwan University of Science and Technology, Taipei, Taiwan, Taiwan; 2The Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan, Taiwan

 

This study attempts to use video recording as a tool for physiology monitoring in an MRI scanner. During a cardiac cycle, facial skin blood perfusion changes alter optical path of ambient light emitted to the subject¡¦s face. Using a conventional digital camera to capture the changes of the reflected light and using ICA analysis to remove other sources in light, we identify that this method is feasible in a low-light MRI bore. This method is an optic-based technique which avoids the problem associated with switching gradient system.

 

                    1300.   MR-Compatible Normobaric Gas Mixer for Hypercapnic Vasoreactivity Studies on Humans

                                L. Lamalle1, 2, J.-B. Menut3, S. Vergès4, J. M. Warnking5, 6, A. Krainik7, 8

                                1Inserm — US 17, Grenoble, France; 2Université Grenoble Alpes — UMS IRMaGe, Grenoble, France; 3SMTEC, Sport & Medical Technologies S.A., Nyon, Switzerland; 4Université Grenoble Alpes — Laboratoire HP2, Grenoble, France; 5Inserm — U836 (Équipe 5), Grenoble, France; 6Université Grenoble Alpes — Grenoble Institut des Neurosciences, Grenoble, France; 7Université Grenoble Alpes — Faculté de Médecine, Grenoble, France; 8CHU de Grenoble — Unité IRM, Grenoble, France

 

A normobaric gas mixer was developed to allow MR-based hypercapnic vasoreactivity studies on humans. It operates safely close to the magnet and can be remotely computer controlled. Hypercapnic episodes with FiCO2 less than 10 % can be programmed to chain in succession for prescribed numbers of MR scanner trigger events. Device performance is demonstrated in a cerebral BOLD block-designed fMRI experiment.

 

                    1301.   3D Printing of MRI Compatible Components:  Why Every MRI Research Group Should Have a Low-Budget 3D Printer

                                Karl-Heinz Herrmann1, Clemens Gärtner1, Martin Krämer1, Daniel Güllmar1, Jürgen R.  Reichenbach1

                                1Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany

 

The capabilities of a current low budget 3D printer was evaluated by designing and building a mouse head fixation custom fitted to a dedicated recieve coil. While the low budget 3D printing technology has not yet outgrown some inherent problems like warping due to thermal stresses, it was possible to build a fully functional multipart mouse head fixation. The printing material Polylactic Acid (PLA) is fully MRI compatible as even its susceptibility is close to biological tissue. We therefore consider a low budget 3D printer a quite useful assessory for MRI labs.

                    1302.   Evaluation of an MR Compatible Head Fixation Device Using a Custom-Made 3D Printed Frame in Combination with a Thermoplastic Head Mask

                                Daniel Güllmar1, Karl-Heinz Herrmann2, Clemens Gärtner2, 3, Nico Banz4, Thomas G. Wendt4, Jürgen R. Reichenbach2

                                1Medical Physics Group, Institute of Diagnostic and Interventional Radiology I , Jena University Hospital - Friedrich Schiller University Jena , Jena, Germany; 2Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany; 3Medical Engeneering and Biotechnology, University of Applied Sciences, Jena, Germany; 4Department of Radiotheraphy and Radiooncology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany

 

Head fixation using a custom-made frame in combination with a thermoplastic head mask was evaluated in terms of repositioning accuracy as well as degree of immobilization. In back-to-back scans regular fixation using clamps performed equally well compared to mask fixation. Repositioning accuracy using mask fixation was found to be very high (< 0.2mm, < 0.2°). Under heavy motion the degree of immobilization did not exceed 1.5 mm in translation and 1.5° in rotation. The approach can be used to acquire MR scans which require minimal head motion during very long scan times (e.g. DTI, fMRI, Perfusion, high-res anatomy scans).

                    1303.   An MRI Compatible Surface Scanner

                                Oline V. Olesen1, 2, Jakob Wilm1, 3, Andre van der Kouwe2, Rasmus R. Jensen1, Rasmus Larsen1, Lawrence L. Wald2

                                1DTU Compute, Technical University of Denmark, Lyngby, Denmark; 2Athinoula. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, MA, United States; 3Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen, Denmark

 

We present the hardware design of an optical surface scanner for in-bore applications. It is the first remote structured light scanner that transmits projected patterns onto the subject and captures their images through optical fiber bundles. MPRAGE and EPI images of a phantom were acquired with simultaneous surface scanning. The system design was shown to be MRI compatible and functional on the Siemens mMR Biograph. This technology could be used for monitoring and markerless tracking of surfaces e.g. real-time motion correction feedback without the use of MR navigators or optical markers.

                    1304.   Imaging in a Rotating Frame:  MRI Without B0 Gradients

                                Steven M. Wright1, Brian J. Bass1, John C. Bosshard1

                                1Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States

 

Spatial encoding with reduced reliance on Bo gradients has always been an interest for specialized applications. Some investigators have demonstrated entirely replacing gradient encoding in one direction and rotating a receiver coil at very high rates to create a virtual array for RF spatial encoding.  Here we demonstrate early results from a novel planar imaging technique for MR imaging that uses no gradients at all, performing all spatial encoding by a combination of RF encoding and rotating the object. The specific interest here is the development of a simple, low-cost imaging system that is robust to magnetic field homogeneity.

Traditional Poster

Array Coils & Systems

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1305.   Four Channel Transceiver Array for Functional Magnetic Resonance Spectroscopy in the Human Visual Cortex at 9.4 T

                                Andreas Pfrommer1, Nikolai Avdievich1, Anke Henning1, 2

                                1Dept. of High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Baden-Württemberg, Germany; 2Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland

 

RF coils for functional magnetic resonance spectroscopy at ultra-high field strength must be designed with high SNR, high transmit efficiency and optimized to guarantee SAR safety. With numerical EM simulations we compared two possible 4 channel RF coil setups for the application in the human visual cortex. It turned out that overlapping loop elements can provide 12.5 % more B1+ /&#8730;SAR(10g) than without overlap for this particular case. Based on the simulation we have constructed a tight fit 4-channel transceiver head phased array. We could reach a B1+ of 63 µT in a 12.4x12.4 mm² sized voxel in the visual cortex region in a human head-and-shoulder phantom.

                    1306.   Evaluation of ICE and Capacitive Decoupling Methods Using in 8-Channel Loop Array Coils at 7T

                                Xinqiang Yan1, 2, Xiaoliang Zhang3, 4, Chuangxin Ma2, Long Wei2, Rong Xue1

                                1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Insititute of  Biophysics, Chinese Academy of Sciences, Beijing, China; 2Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 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

 

In this study, two eight-channel transmit/receive volume-type loop array coils were built for human head imaging at 7T by using the ICE decoupling method and capacitive decoupling method, respectively. We have conducted research on comparison between these arrays in terms of S-parameter matrix, SNR and parallel imaging capability. Compared with the capacitively decoupled array, the ICE-decoupled array has better isolation between adjacent coil elements, higher SNR at periphery area and better parallel imaging capability. Additionally, ICE decoupling method is more robust that decoupling loops do not need to be retuned for different loads.

                    1307.   High SNR Bilateral Breast MRI with a Dual Transmit, 26-Channel Receive RF Coil with Simultaneous 31P CSI at 7 Tesla

                                Tijl A. van der Velden1, Michel Italiaander2, Wybe J.M. van der Kemp1, Alexander Schmitz1, Kenneth Gilhuijs1, Peter Luijten1, Vincent O. Boer1, Dennis W.J. Klomp1

                                1Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2MR Coils, Drunen, Netherlands

 

Synopsis: Strong T1-weighted, high resolution dynamic contrast enhance MR images are key in the detection of breast cancer. Combined with phospholipid detection using 31P Chemical Shift Imaging (CSI), the earlier alterations in metabolism can be obtained using a novel decoupling loop a bilateral breast coil was designed for uncompromised 1H and 31P MR(S)I at 7 tesla enabling increased spatial and temporal resolution with the 26 1H receiver channels integrated in the coil. We demonstrate high spatial and temporal resolution imaging and 31P CSI in patients with breast cancer.

                    1308.   Comparison of Three Different Microstrip Transmit Elements for Use in Multichannel Tx/Rx Body Coils at 7 Tesla

                                Stephan Orzada1, Klaus Solbach2, Mark E. Ladd, 13, Andreas K. Bitz, 13

                                1Erwin L. Hahn Institute for MRI, Essen, Germany; 2Institute of Microwave and RF Technology, University of Duisburg-Essen, Duisburg, Germany; 3Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

 

In this study three different elements are compared regarding their suitability for large-diameter, multi-element body coils at 7T: the centrally-fed microstrip line2 (MSL), the centrally-fed microstrip line with meanders3, and a new design where the meanders of the aforementioned element are loaded with a dielectric to eliminate the end capacitors. Comparison is done through simulations and phantom experiments on the single elements. The element with dielectrically loaded meanders shows a more focused sensitivity then the MSL or the meander element terminated with capacitors, which might be beneficial for parallel transmit and parallel reception.

 

                    1309.   Optimization of B1 Field Homogeneity Along the Longitudinal Direction for 7T MTL Resonators by Using a Multi-Row Design

                                Xinqiang Yan1, 2, Xiaoliang Zhang3, 4, Chuangxin Ma5, Long Wei5, Rong Xue1

                                1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Insititute of  Biophysics, Chinese Academy of Sciences, Beijing, China; 2Key Laboratory of Nuclear Analysis Techniques,  Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 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; 5Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China

 

In this work, we used a double-row microstrip transmission line (MTL) array by varying the termination capacitance distribution to generate more homogeneous B1+ field along longitudinal direction. The coupling between elements of adjacent rows was reduced by using the induced current compensation decoupling method. Full-wave electromagnetic modeling was used to study and compare the performances of the new design and the conventional MTL resonator. The B1+ homogeneity improvement along longitudinal direction was obvious and this new design has also paved the way for similar designs for human imaging.

                    1310.   A Hybrid Dielectric/birdcage Double Tuned Volume Resonator for High Field MRI

                                Sebastian Arnold Aussenhofer1, Paul de Bruin1, Andrew Webb1

                                1Radiology, C.J. Gorter Center for High Field MRI LUMC, Leiden, Select, Netherlands

 

This work describes a new principle to build double tuned volume resonators for high field human imaging by combining a dielectric HEM mode resonator with a birdcage coil. The dielectric resonator acts as the proton transceiver (298 MHz at 7T); the birdcage acts as the sodium transceiver (79 MHz at 7T). By inserting the birdcage into the dielectric coil a double tuned volume coil can be constructed if each of the birdcages rungs is proton frequency trapped. The homogenous B1 fields of the two resonators are preserved in the joint setup. A resonator was constructed to acquire high resolution proton and sodium images of the human wrist.

                    1311.   An 8 Channel Transceiver Phased Array Coil Combined with a Surgical Robot for an MR Assisted Robotic Surgery.

                                Seunghoon Ha1, Haoqin Zhu1, Labros Petropoulos1

                                1Research and Development, IMRIS Inc, Minneapolis, MN, United States

 

To fully utilize Robotic assisted surgery in MR, it is imperative that the RF coil design should be fully integrated with a Head Fixation Device. The combination of the RF coil, HFD, and Robotic surgery introduces clinical requirements and needs that cannot be satisfied with the design of a traditional RF coil that is targeted for diagnostic MR Imaging. In this study, we propose an new eight channel transceiver array coil that is seamlessly integrated with an MR safe HFD and an MR safe Robot by minimizing peak and average SAR, inside the surgical field containing the RF field outside the robot and optimizing image quality and SNR using EM simulation results  and verifying the results  with measurements on a prototype coil.

                    1312.   Comparison of RF Resonators Using Microstrip for Human Head at 3T

                                Hyeok-Woo Son1, Young-Ki Cho1, Hyoungsuk Yoo2

                                1Kyungpook National University, Daegu, Korea; 2University of Ulsan, Ulsan, Korea

 

16-channel head coils using a variety of RF resonators were tested on study participants at 3 Tesla, and the penetrated RF magnetic fields were compared amongst four different RF resonators in a spherical phantom. we proposed using a 16-channel coil with a SIR with four arms, and we compared it to other RF resonators based on microstrip transmission lines. The 16-channel coil provided better B1+ fields and can be effectively controlled for parallel imaging in 3 Tesla MRI systems. 16-channel head coils using the SIR with four arms for parallel imaging could be used in hospitals for higher quality imaging.

                    1313.   A Novel Design Approach for Planar Local Transmit/receive Antennas in 3T Spine Imaging

                                Johanna Schöpfer1, Klaus Huber1, Stephan Biber2, Sebastian Martius1, Helmut Greim2

                                1Corporate Technology, Siemens AG, Erlangen, Germany; 2Healthcare Sector, Siemens AG, Erlangen, Germany

 

The human spine is one of the most frequently imaged body parts in clinical MRI. The imaging performance can be restrained by SAR restriction, B1+-inhomogeneities or insufficient B1+-peak values. In the following an optimized local transmit antenna structure for spine imaging is presented which offers reduced SAR values, improved B1+-inhomogeneity and reduced power requirements in comparison to examination with the body coil antenna. Following EM-simulations, the antenna structure was manufactured and successfully integrated, showing significant potential for future work in 3T MRI imaging with local transmit coils.

                    1314.   Design and Implementation of Flexible Printed Receive Coils Arrays

                                Joseph Russell Corea1, Anita Flynn1, Galen Reed1, 2, Peter Shin2, Greig Scott3, Ana Claudia Arias1, Michael Lustig1

                                1Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, United States; 2Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 3Electrical Engineering, Stanford, Stanford, CA, United States

 

Creating receive coil arrays using ultra-high quality components is the standard method of fabrication for arrays today.  However, concessions can be made trading off excess quality factor for a more conformable device using screen printed materials.  This is possible because in clinical scanners, the system is body noise dominated so lowering the quality factor of the coil does not necessarily lower the signal-to-noise ratio of the image.  Here we discuss the implications of using printed materials for creating receive coil arrays and include a demonstration of a 4-channel fully printed prototype on different areas of a volunteer.

                    1315.   A 64-Channel Cardiac Receive-Only Phased Array Coil for Cardiac Imaging at 3T

                                Mark Schuppert1, Boris Keil2, Bastien Guerin2, Stefan Fischer1, Robert Rehner3, Lawrence L. Wald2, 4, Laura M. Schreiber1

                                1Section of Medical Physics, Department of Radiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany; 2A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; 3Siemens AG, Healthcare Sector, Erlangen, Germany; 4Harvard Medical School, Boston, MA, United States

 

A 64-channel cardiac receive-only phased array prototype coil was built. We show its use for accelerated imaging (tGRAPPA, acceleration factors R = 3, 5, 7, and 8) in comparison to a 38-channel commercial coil setup (Body 18/Spine 32 Tim coils). Compared to the commercial coil setup, the achieved center SNR with the 64-channel coil was 6% less using optimally combined complex data in phantom measurements. Nonetheless, at R = 7 mean noise amplification in phantom measurements was 50% less with the new coil. In vivo image quality was superior with the 64-channel cardiac phased array coil at R=5 and R=7.

                    1316.   Non-Resonance 16-Element Transceiver Array for Human Head Imaging at 7T

                                Yong Pang1, Xiaoliang Zhang1, 2

                                1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States; 2UC Berkeley/UCSF Joint Bioengineering Program, CA, United States

 

Decoupling issue is a challenging problem in transceiver array designs at high fields. The Non-resonance RF method (NORM) using traveling wave provides a promising way to alleviate this problem and also has multi-frequency excitation and reception capability. In this work, a 16-element transceiver NORM array for 7T human head imaging is modeled and simulated using FDTD method. The unmatched decoupling and excellent g-factors were achieved, indicating the feasibility of parallel imaging using the proposed NORM array. The same NORM array is able to perform multinuclear excitation and detection, such as C13 and P31, which is verified by FDTD simulation.

                    1317.   A Double-Row Transmit Array with Broadband Sheath-Wave Damping for 7T Human Head Imaging

                                Roland Müller1, Andreas Schäfer1, Debra S. Rivera1, Robert Turner1, Harald E. Möller1

                                1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

 

Goal of the project was to design an eight-element, double-row, transmit RF array coil for imaging of human heads at 7T. Both rows should be tuned independently using the re&#64258;ected power minimization approach. At high fields, the common mode problem is presenting a source of loss as well as a potential safety issue.

This was addressed by a PCB based 3D coil structure.

The combination of balanced feeding,  balanced feed lines and resistor-bypassed line shield gaps was sufficient to eliminate sheath waves and hand effects. No conventional traps were required.

A good longitudinal coverage of B1+ field can be shown.

 

                    1318.   Effects of Co-Planar Element Shielding on Array Performance at 7T

                                Samantha By1, Joseph V. Rispoli1, Ivan Dimitrov2, 3, Sergey Cheshkov2, 4, Craig Malloy2, 4, Steven M. Wright, 15, Mary Preston McDougall1, 5

                                1Biomedical Engineering, Texas A&M University, College Station, TX, United States; 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 3Philips Medical Systems, Cleveland, OH, United States; 4Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 5Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States

 

At higher field strengths, shielding of RF coils to mitigate radiation losses becomes increasingly necessary.  In an array configuration, however, shielding individual elements can be complex, particularly when the elements are overlapped for geometric decoupling.  This work presents the benefits of a co-planar shielding configuration of the elements of an overlapped array at 7T.  Compared to the unshielded array, the shielded array provided a 39% improvement in mean SNR throughout the entire phantom, an average decrease in mean g-factors for all three views of 8.9%, and a lower power setting required to produce a 90 degree tip angle.

                    1319.   Replacing Individual Baluns with Quarter Wavelength Baluns in Multi-Channel Arrays

                                Thomas Grafendorfer1, Greig Scott2, Paul Calderon3, Fraser Robb4, John Pauly2, Shreyas Vasanawala5

                                1Advanced Coils, GEHC Coils, Stanford, CA, United States; 2Electrical Engineering, Stanford University, CA, United States; 3Engineering consultant, Stanford Radiology, CA, United States; 4Advanced Coils, GEHC Coils, OH, United States; 5Radiology, Stanford University, CA, United States

 

Baluns and cable traps are widely used in coil arrays to prevent common mode currents on cables and feeding lines that can severely impact coil performance. But this approach is often done in a trial and error fashion; arbitrarily moving and adding Baluns until the coil somehow works. Here we show a more controlled approach, where ground loops formed by cables are purposely set to hold certain resonance frequencies. In that case individual Baluns can be replaced with quarter wavelength Baluns, which is noting else than shorting individual cable shields together at the right location.

                    1320.   Four Element Endorectal Array Coil for Improved Sensitivity in Human Prostate Imaging

                                Ronald D. Watkins1, Kim Butts Pauly1

                                1Radiology, Stanford University, Stanford, CA, United States

 

We have designed, built, and tested a miniature four element linear surface coil array for high resolution imaging of human prostate. The prototype coil has demonstrated a factor of 2 increase in SNR near the array, over a single coil equal to the size of the array. In addition it is possible to perform parallel imaging with this array.

                    1321.   Design of a 96-Channel Bilateral Prone Breast Array for High Performance Parallel MRI

                                Mike J. Smith1, Scott B. King1

                                1National Research Council of Canada, Winnipeg, Manitoba, Canada

 

We investigate SNR and parallel imaging limits of prone positioned MR breast imaging by evaluating different 96-Channel receive array coils. We show that the 96-Channel array has SNR and g-factor capabilities that allow 3x faster breast MRI than currently available with 16-Channel coils.

                    1322.   An Eight-Channel Transmit/receive Phased-Array Head Coil with an ICE Decoupling Method at 7T

                                Xinqiang Yan1, 2, Xiaoliang Zhang3, 4, Chuangxin Ma2, Long Wei2, Rong Xue1

                                1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Insititute of  Biophysics, Chinese Academy of Sciences, Beijing, China; 2Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 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

 

In this work, an eight-channel transmit/receive loop array with induced current elimination (ICE) decoupling method was built and investigated to demonstrate its feasibility and robustness for human head imaging at 7T. This array has been validated through bench tests and in-vivo human head MR imaging experiments. Isolation between the adjacent loop elements is better than -25dB by employing this new design. The ICE-decoupled array also shows excellent parallel imaging capability that the average g-factor of human head in the sagittal plane was as low as 1.14 when acceleration factor achieves 4.

                    1323.   An 8-Channel Integrated Balun Phased Array (IBPA) for Small Anatomical Features

                                Wolfgang Loew1, Randy O. Giaquinto1, Brynne Williams1, J. Matthew Lanier1, Christopher Ireland1, Ronald Pratt1, Charles Dumoulin1

                                1Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States

 

A 3 Tesla 8-channel receive phased array for small anatomical features is presented in this abstract. The array uses a novel coil design integrating a balun into each coil element. Coupling and matching was assessed through network analysis. High-resolution imaging experiments were performed on a phantom and human fingers confirming high image quality and proof of concept.

                    1324.   Prototype 8-Channel Parallel Transmit Body Array in a Clinical 3T System

                                Wei Luo1, 2, Christopher T. Sica1, YeunChul Ryu3, Yang Qing1, Christopher M. Collins4

                                1Radiology, Pennsylvania State University, Hershey, PA, United States; 2Engineering Science & Mechanics, Pennsylvania State University, University Park, PA, United States; 3Samsung, Korea; 4Radiology, New York University, New York, NY, United States

 

A prototype of an eight-channel transmit array which can be inserted into a commercial 3T system above the patient bed and used with commercial receive-only arrays was designed and implemented based on our previous studies. This design benefits from the signal-to-noise ratio offered by the commercial receive-only array and restricts the geometry and placement of the array elements. Here, we report progress on this prototype, including its implementation, preliminary shimming result on phantom, and its very first in vivo images.

                    1325.   An Optimized 8-Channel Helmet Array for Head Imaging at 6.5 MT

                                Cristen D. LaPierre1, 2, Lawrence L. Wald1, 3, Matthew S. Rosen1, 2

                                1Department of Radiology, A.A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 2Department of Physics, Harvard University, Cambridge, MA, United States; 3Harvard-MIT Division of Health Science and Technology, Cambridge, MA, United States

 

A low-field imager offers a potentially transportable and rapidly deployable human imaging system without many of the system requirements of typical scanners. The aim of this study was to construct an 8-channel receive-only helmet array for imaging the human brain. The helmet was 3D printed. Coils consisted of 4x12 cm and 4x14 cm loops, each with 30 turns of 24 AWG copper wire. Geometric decoupling between nearest neighbors was at least -30 db while next nearest neighbors was -6 dB. Future work will compare parallel imaging to incoherent random undersampling and SENSE.

                    1326.   Performance Comparison of a Form Fitted Coil Array Vs. a Quadrature Birdcage Coil for 31P MRS Studies in the Human Calf at 7T

                                Sigrun Goluch1, 2, Andre Kuehne1, 2, Ewald Moser1, 2, Elmar Laistler1, 2

                                1MR Center of Excellence, Medical University of Vienna, Vienna, Austria; 2Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria

 

This work compares the performance of a 3 channel transceive 31P surface coil with a comparable sized 16-leg birdcage for the application in 31P localized spectroscopy experiments in the human calf at 7T with 3D electromagnetic simulation. B1+ as well as SNR calculation for a       comprehensive investigation is presented for both designs, showing higher B1+ and SNR in the regions of interest for the surface coil, while as expected the birdcage exhibits better homogeneity. Since the ROIs are small voxels the advantage of better homogeneity is of minor importance compared to high sensitivity in terms of B1+ and SNR.

                    1327.   Inverse RF Array Head Coil Design for MRI-LINAC System

                                Yimeng Wang1, Yu Li1, Feng Liu1, Ewald Weber1, Hector Sanchez Lopez1, Stuart Crozier1

                                1School of ITEE, University of Queensland, Brisbane, Queensland, Australia

 

This paper focuses on the theoretical inverse design of cylindrical head RF phased array coils applied in the Magnetic Resonance Imaging Linear accelerator (MRI-Linac) system. A MRI-Linac system is the combination of cancer detection and real time, image guided radiotherapy.  In this work, a RF phased-array coils with gaps are designed. Those gaps provide easy access for the accelerator without any disturbance, and multiple receiver coils can realize the fast imaging requirements. The simulation results show that homogeneous magnetic field within a given region of interest (ROI) can theoretically be achieved by the new designed coil.

                    1328.   Spatial Normalization Can Morph RF Coils Into Geometries Optimized for FcMRI Studies in Specific Brain Regions

                                Iain P. Bruce1, L Tugan Muftuler2, 3, Daniel B. Rowe1, 2

                                1Mathematics, Statistics and Computer Science, Marquette University, Milwaukee, WI, United States; 2Biophysics, Medical College of Wisconsin, WI, United States; 3Center of Imaging Research, Medical College of Wisconsin, WI, United States

 

Many degenerative brain disorders are commonly associated with specific regions of the brain that are often off-center and can reside within aliased regions prior to a SENSE reconstruction. While a conventional array of rectangular coils may generate the most uniform magnetic field sensitivities throughout the brain, the human brain is not symmetric, and such sensitivities may not be optimal for fcMRI studies in all regions. This study proposes an approach of using spatial normalization together with an iterated conditional modes algorithm to morph an array of rectangular coils into a geometry that is more optimal for a specific ROI.

                    1329.   Numerical Analysis of a Four Channel Array with Intrinsically Dual Tuned Single Element Antennas Providing a Congener Resonant Behavior for Combined 23Na/1H MRI at 7T

                                Jan Taro Svejda1, Daniel Erni1, Andreas Rennings1

                                1General and Theoretical Electrical Engineering (ATE), University of Duisburg-Essen, Duisburg, NRW, Germany

 

An intrinsically dual tuned single element antenna providing a congener resonance behavior is utilized within a four channel setup for combined 23Na and 1H MRI at 7T. The antenna is based on the composite right-/left-handed transmission line technique with short circuited line terminations. The array shows a homogeneous B1-field distribution for both resonances while the specific absorption rate is evenly distributed along the antennas.

                    1330.   Static Shim Optimization of 7T Dual Row Arrays

                                Mikhail Kozlov1, Nicolas Boulant2, Robert Turner1

                                1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Saxony, Germany; 2CEA, DSV, I2BM, NeuroSpin, UNIRS, Saclay, France

 

No synopsis available

                    1331.   Cartesian Feedback Configuration with Direct RF Signal Injection for Power Amplifier Linearization at 1.5T MRI

                                Jonathan Y. Lu1, Pascal P. Stang1, John M. Pauly1, Marta G. Zanchi2, Greig C. Scott1

                                1Dept of Electrical Engineering, Stanford University, Stanford, CA, United States; 2School of Medicine, Stanford University, Stanford, CA, United States

 

We demonstrate a modified version of Cartesian feedback, an RF power amplifier linearization technique, for use at 1.5T. In this feedback configuration, the MRI RF signal is directly injected at a point in the feedback loop that allows us to eliminate the initial down-converter needed to convert the MRI signal to baseband or intermediate frequency. Amplifier linearization is important especially in multichannel transmit where unpredictable coil loading conditions can affect amplifiers in the stage before, while this particular arrangement allows appreciable components savings and simplification in architecture when multiple coils are used.

                    1332.   B1+ Distortion by Residual Currents in Decoupled Receive Arrays

                                Ed B. Boskamp1, David M. Goldhaber1

                                1Engineering, GE Healthcare, Waukesha, WI, United States

 

Whole body RF transmit coil B1+ uniformity distortion due to residual currents in receive arrays is being studied. Complex arrays may be decoupled from B fields at first glance, but currents can still be induced in the copper traces by E fields and by B fields in loops that are not apparent but do exist due to parasitics. Proper placement of the blocking networks is crucial to minimize currents in the array and thus B1+ distortion.

                    1333.   Simultaneous Deep-Local Hyperthermia and 1.5T MR Imaging – an Experimental Systems Interactions Study

                                Matthew Tarasek1, Tomas Drizdal2, Ruben Pellicer2, Wouter Numan2, Paolo Togni2, Gyula Kotek2, Gerard van Rhoon2, Maarten Paulides2, Desmond Yeo1

                                1MRI, GE global research, Niskayuna, NY, United States; 2Erasmus Medical Center, Netherlands

 

The MRlabcollar was designed as a magnetic resonance (MR)-compatible array for simulation guided conformal radiofrequency (RF) hyperthermia treatment of head and neck (H&N) tumors. Here we present a comprehensive characterization of interactions between the MRI scanner and MRlabcollar to analyse MR image quality, especially with simultaneous operation of both RF sub-systems. We characterize image SNR, the relative B1+ uniformity, B0 distortion due to placement of the array, and phase-difference MR thermometry (MRT) maps acquired during RF transmit from the array. Results show that concurrent heating and imaging is feasible with no significant adverse effects on image quality.

                    1334.   Analysis of Gain and Noise Relationship in RF Feedback Power Amplifier Linearization for Use at 1.5T MRI

                                Jonathan Y. Lu1, Pascal P. Stang1, John M. Pauly1, Marta G. Zanchi2, Greig C. Scott1

                                1Dept of Electrical Engineering, Stanford University, Stanford, CA, United States; 2School of Medicine, Stanford University, Stanford, CA, United States

 

We analyze the possibility of improving noise in an RF Cartesian feedback system, a power amplifier linearization technique, for use at 1.5T MRI. This involves reducing the amount of attenuation in the feedback path without changing the open loop gain of the system and would entail essentially moving the RF input location in our feedback loop. While gain was reduced, we observed a reduction in noise for the same output voltage. This suggests that by driving a closed loop system with reduced gain at higher input power, we could achieve a linear output with reduced noise.

                    1335.   Investigating Interactions Between a TMS System and a Novel MR Device for Concurrent TMS/fMRI Experiments

                                Lucia Isabel Navarro de Lara1, 2, Christian Windischberger1, 2, Jürgen Sieg1, 2, Ewald Moser1, 2, Elmar Laistler1, 2, Andre Kuehne1, 2

                                1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; 2MR Center of Excellence, Medical University of Vienna, Vienna, Austria

 

A dedicated 7-channel MR coil was built for concurrent TMS/fMRI Studies. The developed hardware can be placed under the TMS due to the ultra-slim design in the middle, ensuring efficient TMS stimulation and performing a very high SNR at a target depth up to 6 cm. With these satisfactory results, it had to be shown that the functionality of neither the novel MR head coil or the TMS system when working in combination was affected. The possible interactions of the dedicated MR coil on the TMS device and vice versa were the focus of this work.

                    1336.   A Method to Calculate the Noise Factor of the Receive Coil Matching Network

                                Xueming Cao1, Elmar Fischer1, Jan G. Korvink2, Jürgen Hennig1, Maxim Zaitsev1

                                1Department of Radiology, University Medical Center Freiburg, Freiburg, Germany; 2Institute of Microsystem Technology, Freiburg, Germany

 

In ordinary MRI experiments using local receive coil, major noise sources in signal reception are the sample and the preamplifier. However, as the sizes of individual coil elements becomes smaller, noise contribution from the coil matching network needs to be taken into account. Here, we present a method to calculate the noise factor of coil matching network. Approximations are also developed to allow the estimation of a coil matching network noise factor on the RF bench. Based on the calculations, a method to reduce the coil matching network noise factor is presented.

                    1337.   New Matching Networks for Coil and Preamplifier

                                Xueming Cao1, Maxim Zaitsev1, Jürgen Hennig1, Jan G. Korvink2, Elmar Fischer1

                                1Department of Radiology, University Medical Center Freiburg, Freiburg, Germany; 2Institute of Microsystem Technology, Freiburg, Germany

 

Based on the assumption that the sample and preamplifier are the dominant noise sources for MRI, the coil loop is matched to 50 Ohm through a coil matching network and the preamplifier is noise matched to 50 Ohm too, through another matching network. However, with receiving coils in an array becoming increasingly smaller, the noise contributed from their matching networks cannot be neglected. Here we present two methods to simplify the coil and preamplifier matching networks, therefore their noise contribution is reduced

 

                    1338.   Automatic Matching of Transmit Arrays with Optically Controlled Capacitors

                                Giorgos Katsikatsos1, Klaas Paul Pruessmann1

                                1Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland

 

A closed-loop controlled matching for Tx-arrays for a 7T scanner has been implemented as an autonomous system to react to load changes in various stages of an MR experiment. Building blocks of the system are the L-matching networks, built from custom low-loss capacitors actuated by piezoelectric motors, controlled by an external computer. The feedback is provided by a network analyzer which triggers the re-matching procedure. The matching algorithm is based on previous knowledge about the matching circuit connected to the array and uses common objective functions to detect the best matching settings for arbitrary loads.

                    1339.   A Fully Integrated Automatic Tune and Match System for an 8-Channel Transmit/Receive Cardiac TEM Array at 7T: Initial Results in a Phantom and Volunteers

                                Graeme A. Keith1, Christopher T. Rodgers1, Aaron T. Hess1, Carl J. Snyder2, J Thomas Vaughan2, Matthew D. Robson1

                                1Oxford Centre for Clinical Magnetic Resonance Research, University Of Oxford, Oxford, Oxfordshire, United Kingdom; 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

 

Results in both a saline phantom and in humans are presented for an auto-tune system using piezoelectric actuators and MATLAB control. The system was implemented on an 8-channel pTx cardiac TEM array for use at 7T. A rigorous performance evaluation algorithm was run on the phantom and found that in the majority of cases the S11 was significantly improved by the system. The system was then employed on human subjects, and it was found that it could successfully tune on a person in a maximum of 6 minutes. The system is now in routine use in our lab.

                    1340.   Single Configuration of Coil and High-Permittivity Material Improves Performance for a Wide Range of Subjects

                                Christopher M. Collins1, Qing X. Yang2

                                1Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States; 2Radiology, The Pennsylvania State University, PA, United States

 

Using numerical simulations, we explore the potential of a single high-permittivity receive head coil former to improve performance of a large encircling transmit array at 7T for six different human subjects with a wide range in size and morphology. This is important to demonstrate the possibility of incorporating HPMs into arrays for high-throughput, high performance MRI.  The ability to perform RF shimming with the large volume array was not adversely affected by the presence of the high-dielectric former in any of the subjects and the former greatly improved efficiency and homogeneity of the transmit array for all subjects.

                    1341.   Improvement of Parallel Imaging Using High Permittivity Material (HPM) - Demonstration with Liver Imaging at 3T

                                Zhipeng Cao1, Wei Luo2, Sebastian Rupprecht3, Christopher Sica3, Michael Lanagan2, Christopher M. Collins4, Qing X. Yang3

                                1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 2Engineering Science and Mechanics, Penn State University, University Park, PA, United States; 3Radiology, Penn State University, Hershey, PA, United States; 4Radiology, New York University, New York, NY, United States

 

Experimental demonstration of using HPM to improve parallel imaging on liver imaging at 3T. The HPM resulted in smaller g-factor loss and more SNR preservation with high data undersampling factors.

                    1342.   Approaching Ultimate SNR: Comparison of Composite and Surface Coil Arrays

                                Adam Maunder1, Mojgan Daneshmand1, Pedram Mousavi1, B. Gino Fallone2, Nicola De Zanche2

                                1Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada; 2Oncology, University of Alberta, Edmonton, Alberta, Canada

 

It has been shown that at high MRI frequencies current patterns other than those provided by surface coils are required to approach the ultimate SNR. SNR improvements in realistic arrays become limited due to noise from coils and matching networks in large arrays. Arrays of three orthogonal coils are naturally decoupled, provide complementary sensitivities and allow the use of larger, body loss dominated, coils. Simulations of large 18-, 36- and 54-element arrays composed of composite and surface coils are compared in terms of SNR and parallel imaging performance. Noise contributions from the coil, matching networks and preamplifiers are included for a realistic comparison.

                    1343.   Active Optical-Based Decoupling Circuit for Receiver Endoluminal Coil

                                Reina Ayde1, Raphael Sablong1, Gwenael Gaborit2, 3, Lionel Duvillaret3, Anne-Laure Perrier1, Olivier Beuf1

                                1CREATIS - CNRS UMR 5220 – INSERM U1044, University of Lyon 1, Villeurbanne, Rhone-Alpes, France; 2IMEP-LAHC UMR 5130, University of Savoie, Rhone-Alpes, France; 3Kapteos, Rhone-Alpes, France

 

The use of metallic coaxial cables in MRI could induce local high Specific Absorption Rate. Optical fiber link could be an alternative to coaxial cables to ensure patient safety. In order to assure a complete optical endoluminal receiver coil, an optical system for decoupling the receiver coil was made. The MRI for a phantom of ionized water was taken with three endoluminal coils with different decoupling system:  classical, optical and without decoupling system. The SNR and the uniformity of signal distribution were studied and compared. The results show that the decoupling system works perfectly and does not induce field inhomogeneity.

Traditional Poster

Non-Array RF Coils, Dielectrics & Waves

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1344.   A Susceptibility Matched Endorectal Coil Design Suited for the MRS Examination of the Rectal Wall

                                Jean-Marie Verret1, 2, Frank Pilleul3, 4, Cécile Rabrait2, Olivier Beuf1

                                1Université de Lyon; CREATIS; CNRS UMR 5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Villeurbanne, France; 2General Electric Healthcare, Buc, France; 3Hospices Civils de Lyon; Département d’imagerie digestive; CHU Edouard Herriot, France; 4Centre Léon Bérard - Centre de Lutte contre le Cancer, France

 

A susceptibility matched endorectal coil was tested and compared against a classical endorectal coil design. For different phantom angulations, it enabled a significant decrease (~30%) of the FWHM of spectra acquired on in vitro NMR tubes. These promising results and the restricted FWHM observed suggest the interest of this new coil for the acquisition of in vivo spectra especially for the characterization of the colorectal cancer.

                    1345.   Endoluminal MRI Coils for Mice Rectal Wall Assessment

                                Hugo Dorez1, Raphaël Sablong1, Laurence Canaple2, Sophie Gaillard1, Driffa Moussata3, Olivier Beuf1

                                1Université de Lyon, CREATIS CNRS UMR 5220 – INSERM U1044 – INSA Lyon 1, Villeurbanne, Rhône-Alpes, France; 2Institut de Génomique Fonctionnelle de Lyon, Université de Lyon 1, UMR 5242 CNRS, Ecole Normale Supérieure de Lyon, Lyon, Rhône-Alpes, France; 3Service hépato-gastroentérologie, Hospice Civil Lyon Sud, Pierre-Bénite, Rhône-Alpes, France

 

The purpose of this project research is to assess mice rectum wall using MRI combined with endomicroscopy and conventional endoscopy. Endoluminal MRI coils with active decoupling circuit were developed and characterized on phantoms. Then, in-vivo examination was finally done on mice (c57 black6j). Endoluminal coils improve significantly the local SNR compared to body mice volume birdcage coil. Rectal wall layers are better visualized due to improved spatial resolution achieve with SNR gain. This study shows the feasibility to use small endoluminal coils for mice rectal wall assessment and opens perspectives to better understand rectal pathologies.

                    1346.   Double-Resonant 13C/1H Coil System for {1H} 13C in Vivo NMR Spectroscopy on a 7-T Whole-Body  MR Tomograph

                                Tanja Platt1, Andreas Korzowski1, Reiner Umathum1, Peter Bachert1

                                1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Baden-Württemberg, Germany

 

13C NMR spectroscopy enables a noninvasive quantification of various metabolites in vivo (without or with an enrichment of 13C) and takes advantage of high B0 and of 1H-decoupling. The aim of this study was to design, implement and test a surface coil system for in vivo 1H-decoupled 13C NMR spectroscopy on an experimental 7-T whole-body MR tomograph. The use of a transmission line resonator concept with special frequency selective filter circuits ensures sufficient electromagnetic decoupling for both frequencies (13C, 1H). The resulting coil system allows among other applications the acquisition of high resolution 1H-decoupled 13C NMR spectra in vivo.

 

                    1347.   A Variable Diameter Resonator for High Field Proton and Sodium Musculoskeletal MRI

                                Sebastian Arnold Aussenhofer1, Paul de Bruin1, Andrew Webb1

                                1Radiology Leiden University Medical Center, C.J. Gorter Center for High Field MRI, Leiden, South-Holland, Netherlands

 

A variable-diameter  birdcage resonator has been constructed for sodium imaging of the knee at 7 Tesla (78.85 MHz) in order to optimize sensitivity for different patient sizes. Anatomical proton data are acquired using two microstrip lines (tuned to 298 MHz) mounted on the inside of the shield of the variable diameter  birdcage. The diameter of the birdcage can be varied between 13.5 and 18 cm.  Co-registered proton and sodium images have been  acquired from three  volunteers ranging from a large male subject to a small female one.

                    1348.   Novel RF-Coil Assembly to Simultaneously Investigate fMRI and Electrophysiology in Non-Human Primates in a Large Bore Vertical Magnet

                                Jozien Goense1, 2, Michael Beyerlein2, Jens Hoffmann2, Gunamony Shajan2, Thomas Steudel2, Klaus Scheffler2, 3, Nikos Logothetis2, 4, Hellmut Merkle5

                                1University of Glasgow, Glasgow, United Kingdom; 2Max-Planck Institute for Biological Cybernetics, Tuebingen, Germany; 3University of Tuebingen, United Kingdom; 4University of Manchester, United Kingdom; 5National Institutes of health, MD, United States

 

RF-coil design for combined electrophysiology and fMRI in non-human primates is challenging because any coil design needs to be sufficiently open to allow for electrode access to the brain. Patch antennas allow for a more open design, but since our bore is too small for a 300 MHz traveling wave, we developed an open quadrature transmit coil/antenna placed in-situ. The transmit coil/antenna is capable of producing a sufficiently homogenous B1 field. This device can be used alone in transceiver mode or in combination with dedicated receive arrays which allow for maximum flexibility while maintaining a very high SNR.

                    1349.   A Circularly-Polarized Dual Litz RF Coil for High-Throughput Eight Whole Mouse Head Samples

                                Dung Minh Hoang1, Evelyn B. Voura1, Youssef Zaim Wadghiri1

                                1Radiology, NYU - School of Medicine, New York, United States

 

In this work, we aimed to increase the throughput of ex vivo samples  during overnight unattended sessions by designing a coil and setup accommodating up to eight whole mouse heads.  Using our single channel MRI installation equipped with a gradient insert with a 60-mm diameter spherical volume (DSV), we considered a design based on the use of commonly accessible off-the shelf supplies and ease of sample preparation. Among the various structures examined, a dual litz structure electrically-fed through the mid-point of the rung proved to be the most electrically balanced and homogeneous coil throughout the length of the rung.

                    1350.   A Target-Field Design of Open Multi-Purpose Coil for Musculoskeletal MR Imaging at 3T

                                Rui Zhang1, Qunzhi Chen2, Hongyang Yuan3, Wenchao Cai4, Kai Zhao4, Jue Zhang1, 2, Xiaoying Wang, 24, Jing Fang1, 2

                                1College of Enigneering, Peking University, Beijing, China; 2Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; 3Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; 4Department of Radiology, Peking University First Hospita, Beijing, China

 

MRI plays an important role in diagnosing the diseases of musculoskeletal tissues at different body parts. In this study, based on the target-field method, we proposed a kind of open multi-purpose RF coil with three-plane structure for musculoskeletal MR imaging with satisfied homogeneity and high SNR. The design can meet the need of various body parts and provide large joint movement region for dynamic evaluation. The imaging results have demonstrated the effectiveness and advantage of this proposed design. In the near future, it is believed that the coil can be applied for real-time imaging of joint movement under dynamic situations.

                    1351.   Ladder-Design Volume Coil with Good Uniformity and Signal to Noise for Hyperpolarised 13C Investigations of Animals on a 3T Clinical System

                                Deborah K. Hill1, 2, Craig Cummings1, Jessica K. R. Boult1, Matthew R. Orton1, Yuen-Li Chung1, Thomas R. Eykyn1, 3, Martin O. Leach1, David J. Collins1, Rafal Panek1

                                1CR-UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom; 2Department of Circulation and Medical Imaging, NTNU, Trondheim, Sør-Trøndelag, Norway; 3St Thomas Hospital, Kings College London, London, United Kingdom

 

Signal enhancement by Dynamic Nuclear Polarisation of 13C makes it possible to conduct real-time measurements of low concentration metabolites in vivo. Implementation of preclinical work on clinical systems for DNP studies is attractive, but severely limited by surface coils when moving from subcutaneous to orthotopic and genetically modified models. We describe and characterise a custom-made 13C volume ladder-design coil; the coil shows superior SNR and B1 homogeneity in both phantom studies and in vivo in mice when compared to a typical surface coil.

                    1352.   Design of a Detachable Rat Head Coil for MRI-Guided Stereotaxic Interventions

                                Jijun Han1, Fulang Qi2, Bensheng Qiu2

                                1Department of Electronic Science and Technology , University of Science and Technology of China, Hefei, Anhui, China; 2Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, Anhui, China

 

A detachable head coil with an aperture for MRI-guided stereotaxic rat brain surgery was proposed in this study. The distribution of B1 field was evaluated with numerical calculation. The design of the detachable RF head coil is capable of not only producing the homogenous B1 field, but also providing a free operation path for interventional instruments, which will enable MRI-guided stereotaxic neurosurgery of the rat in vivo.

                    1353.   Current Limited Superconducting RF Coils

                                Christopher Stumpf1, Tobias Frank1, Markus Vester2, Sebastian Martius3, Robert Rehner2, Rainer Engelbrecht1, Lorenz-Peter Schmidt1

                                1Institute of Microwaves and Photonics, University of Erlangen-Nuremberg, Erlangen, Bavaria, Germany; 2Healthcare Sector, Siemens AG, Erlangen, Bavaria, Germany; 3Corporate Technology, Siemens AG, Erlangen, Bavaria, Germany

 

Superconducting self-resonant RF coils can be used in MRI as receive coils to raise the image SNR. Those coils distort the TX magnetic field if they are not detuned. A new method is presented to passively detune self-resonant HTS coils without Q-factor reduction by inserting a taper into the coil structure. Measurements of RF current in the loop at varying absorbed powers show that the current is limited to a maximum value. By reducing the trace width of the taper the maximum current value is reduced and the distortion of the TX field due to induction is decreased.

                    1354.   A Large Volume HEM Dielectric Resonator for Musculoskeletal Applications at Ultra High Field

                                Sebastian Arnold Aussenhofer1, Andrew Webb1

                                1Radiology Leiden University Medical Center, C.J. Gorter Center for High Field MRI, Leiden, South-Holland, Netherlands

 

A water-based dielectric resonator operating in the quadrature HEM mode has been designed and constructed for imaging the human knee at 7 Tesla. The continuous current distribution throughout the resonator results in an extremely simple design of a water-filled annulus connected to the scanner through two impedance matching networks. High resolution images of the knee at sub-millimeter resolution have been acquired in less than 4 minutes using this resonator.

                    1355.   RF Field Enhancement at 0.5T to 1.5T with Ultra High Dielectric Constant Material (UHDC)

                                Christopher Sica1, Sebastian Rupprecht1, Wei Luo2, Raffi Sahul3, Seongtae Kwon3, Michael Lanagan2, Qing Yang1, 4

                                1Radiology, Penn State College of Medicine, Hershey, PA, United States; 2Engineering Science and Mechanics, Penn State University, PA, United States; 3TRS Technologies, State College, PA, United States; 4Neurosurgery, Penn State College of Medicine, Hershey, PA, United States

 

Previous studies have established the benefits offered by dielectric materials at 3T and 7T, including reduced B1+ inhomogeneity and SAR, and increased transmit efficiency and SNR. We explored the application of dielectrics to field strengths of 1.5T and below. Utilizing simulation, the effects of ultra high dielectric constant material (up to &#949;r = 28000) were examined with a block of uHDC material within a phantom at 0.5T, 1T, 1.5T, and 3T. We demonstrated a 2 to 3-fold enhancement in B1 at all field strengths studied, and that lower fields require higher permittivity for enhancement. Experimental results are presented at 1.5 and 3T utilizing available uHDC materials.

 

                    1356.   Single and Multiple Coaxial Inputs to Excite a Cylindrical Waveguide for Traveling Wave MRI at 21.1 T

                                Jose A. Muniz1, 2, Smriti Sagaram1, 3, Jens T. Rosenberg1, 2, Samuel Colles Grant1, 2

                                1National High Magnetic Field Laboratory, The Florida State University, Tallahassee, FL, United States; 2Chemical & Biomedical Engineering, The Florida State University, Tallahassee, FL, United States; 3Electrical & Computer Engineering, The Florida State University, Tallahassee, FL, United States

 

In traveling wave MRI, propagating RF fields are excited through an antenna located at a distance to a given sample such that excitation and detection in MRI can be induced in the far field [1-3]. In this project, traveling wave MRI at ultra-high field is implemented using a concentric waveguide composed of a dielectric filled inner cylinder and an outer copper cylinder with dimensions similar to the magnet bore of a vertical 21.1 T ultra-wide bore magnet. Uniquely, this waveguide is excited by coaxial inputs at single and multiple points.

                    1357.   SNR Enhancement by Free Local Resonators for Traveling Wave MRI

                                Xiaoliang Zhang1, 2, Yong Pang1, Daniel B. Vigneron1, 2

                                1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States; 2UC Berkeley/UCSF Joint Bioengineering Program, San Francisco, CA, United States

 

One of drawbacks of traveling wave MRI is its relatively low signal-to-noise ratio (SNR) due to the use of far fields in excitation and reception. In this work, we present and investigate a method based on free local resonator to improve MR SNR in traveling wave MR. In vivo imaging in rats performed using the proposed free local resonator method at 7T shows a significantly SNR gain over the traditional traveling wave MR.

                    1358.   Accurate and Fast Longitudinal RF Magnetic Field Profiling for 7T Traveling-Wave MRI Systems

                                Thorsten Liebig1, Jan Taro Svejda1, Hongyi Yang1, Andreas Rennings1, Juerg Froehlich2, Daniel Erni1

                                1General and Theoretical Electrical Engineering (ATE), University of Duisburg-Essen, Duisburg, NRW, Germany; 2Laboratory for Electromagnetic Fields and Microwave Electronics (IFH), ETH Zurich, Zurich, ZH, Switzerland

 

We propose an adaptive, fast and accurate scheme for tailoring the RF magnetic field along the bore of a 7T traveling-wave MRI system. The setting consists of a periodic arrangement of quadrature fed resonant CRLH metamaterial ring antennas that are perfectly apt to excite, mold, and dump the propagating TE11 mode within the cylindrical bore. We have achieved narrow field profiles for larynx illumination while tackling the inverse problem using efficient electromagnetic simulations in conjunction with a direct (weighted) least-squares solution. This localized traveling-wave approach has the potential to act as a non-resonant head coils supporting uniform high-resolution brain imaging.

Traditional Poster

RF Modelling & Safety

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1359.   Flip Angle Inhomogeneity Constrained PTx Pulse Design for Minimum Peak Local SAR

                                Mihir Pendse1, Simone Winkler2, Brian Rutt2

                                1Department of Electrical Engineering, Stanford University, Stanford, CA, United States; 2Department of Radiology, Stanford University, CA, United States

 

This work introduces a new minimum SAR spokes-based pTx pulse design algorithm using a spokes trajectory that achieves a desired flip angle inhomogeneity (FAI) threshold while minimizing peak local SAR. Several realistic scan situations are modeled including the use of slightly inaccurate E-field maps for SAR matrix computation to represent patient/body model mismatch and enforcing a constraint on computation time for the optimization. Simulated L-curves show that for four different cases our proposed method achieves equal or lower SAR at low values of FAI compared to prior approaches for SAR-constrained pTx pulse design.

                    1360.   Transmit Field Fitting at 9.4 T Using Analytical Solutions to Maxwell's Equations

                                Michael Stephen Poole1, Desmond H Y Tse1, Arthur W. Magill1, N Jon Shah1, 2

                                1INM-4, Forschungszentrum Jülich, Jülich, Germany; 2Department of Neurology, RWTH Aachen University, Aachen, Germany

 

Transmit B1+ fields need to be accurately acquired for B1+ shimming, kt-points homogenisation, spokes slice selection and parallel RF pulse design. We investigated the application of forcing relative B1+ maps to obey Maxwell's equations in order to provide properly scaled B1+ maps. The method was applied to B1+ maps acquired at 400 MHz in phantom and in vivo and compared to AFI-weighted B1+ and DREAM maps. Furthermore predicted CP mode and kt-points excitations were compared and found to be in good agreement in phantom. The in vivo maps compare qualitatively well with DREAM but conductivity is poorly predicted.

                    1361.   A Numerical Study Comparing Adult Body, Head and Knee Coils for Paediatric MRI

                                Gemma R. Cook1, Martin J. Graves1, Owen J. Arthurs2, Fraser J. Robb3, David J. Lomas1

                                1Radiology, University of Cambridge, Cambridge, United Kingdom; 2Great Ormond Street Hospital, London, United Kingdom; 3GE Healthcare Coils, Aurora, OH, United States

 

Limited availability of dedicated paediatric coils means MRI is typically performed using a transmit/receive coil (considered to be more SAR and SNR advantageous). This study uses a FEM-compatible model of a two month infant inside birdcage coils of typical body, head and knee coil sizes. Transmit and receive fields were calculated and the Specific Absorption Rate (normalised to 4W/kg) was calculated for 1cm³ cubes. SAR maps determined the heat source for further temperature change simulations and maximal SAR and temperature change positions were compared to determine the advantages of each coil.

                    1362.   Illustration of the Impact of Tuning Configuration on 7T RF Coil Simulations

                                Joseph V. Rispoli1, Steven M. Wright, 12, Mary Preston McDougall1, 2

                                1Biomedical Engineering, Texas A & M University, College Station, TX, United States; 2Electrical & Computer Engineering, Texas A & M University, College Station, TX, United States

 

This work illustrates the ramifications of two different approaches to tuning and exciting coils in a high-field simulation environment: 1) forcing an ideal resonant condition versus 2) specifying actual implemented lumped element component values. This abstract uses the example of a loop coil at 7T to demonstrate that results using the second approach exhibit a more uniform current distribution, more homogeneous |B1+|, and 29% lower maximum 10-g average SAR. These results illustrate that power/safety considerations of coils at 7T benefit from a simulation approach including implemented component values rather than forcing ideal resonance as typically simulated at lower field strengths.

                    1363.   Skin Effect Estimation Accuracy in FDTD Coil Simulations

                                Andre Kuehne1, 2, Helmar Waiczies3, Ewald Moser1, 2, Elmar Laistler1, 2

                                1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; 2MR Center of Excellence, Medical University of Vienna, Vienna, Austria; 3MRI.Tools GmbH, Berlin, Germany

 

Dummy Text

                    1364.   Influence of Deep-Region RF Hyperthermia System on B1+ Field of 1.5T MR Scanner: A Simulation Study

                                Tomas Drizdal1, Matthew R. Tarasek2, Ruben Pellicer1, Muhammad H. Chishti2, Wouter C. M. Numan1, Gyula Kotek1, Desmond T. B. Yeo2, Margarethus M. Paulides1

                                1Erasmus MC, Rotterdam, Netherlands; 2GE Global Research, Niskayuna, NY, United States

 

Modeling of radio frequency hyperthermia system and 1.5T MR scanner.

                    1365.   Magnetic Force Estimation Around MRI Magnets

                                Zhenyu Zhang1, Timothy J. Havens1

                                1MR Science & Technology, GE Healthcare, Florence, SC, United States

 

Magnetic forces around MRIs have long been a major concern for operator and patient safety. Due to the difficulty to calculate exact forces, the consensus of the industry is to provide a quantity which represents a good estimation of magnetic forces. This quantity has been included in IEC 60601-2-33. However, the mathematical definition of this quantity has been discussed recently where two suggestions are presented. In this paper, we make an effort to clarify the situation by demonstrating a very simple derivation for one expression and proving that the other expression does not hold in general.

 

                    1366.   Improved Method and Technique for Monitoring SAR in Transmit Coils and Arrays

                                Carl J. Snyder1, Seunghoon Ha1, Haoqin Zhu1, Labros Petropoulos1

                                1IMRIS, Minnetonka, MN, United States

 

With the advent of multi-channel transmitters, ultra-high field imaging and power-intensive techniques like Transmit SENSE, the need for real time power monitoring is becoming an important need. Recent studies have shown that current methods, (monitoring the forward and reflected power at the output of the amplifier) is insufficient as coupling and mismatched coils can change e-field and possibly SAR in transmit arrays.  We are proposing a three-point method, monitoring the forward, reflected on the coax and, monitoring the field at the coil.

                    1367.   Variation in Thermal Maps During RF Heating Due to Variation in Electrical Conductivity in TEM Coil at 298 MHz

                                Muhammad Hassan Chishti1, Matthew R. Tarasek1, Margarethus M. Paulides2, Desmond Teck Beng Yeo1

                                1GE Global Research Center, Niskayuna, NY, United States; 2Erasmus Medical Center, Rotterdam, Netherlands

 

Synopsis:

The uncertainty of electrical conductivity (&#963;) values used in electromagnetic (EM) simulations may lead to incorrect assessment of SAR and risks for tissue ablation in patients during MR imaging at ultra-high fields and in RF thermotherapy applications. In this work, we investigate the errors in predicted temperatures due to incorrect assignment of values to &#963; caused by (i) variations in reported values in the literature, and (ii) temperature-induced variations of &#963;. Results from our full-wave EM (298 MHz) and thermal simulations show that the uncertainties in &#963; may induce temperature prediction errors by up to 5.3 ºC.

 

 

                    1368.   Assessment of Miniaturized RF Traps for RF Heating Reduction and Reception Coil Sensitivity Profile Restoration

                                Jean-Marie Verret1, 2, Frank Pilleul3, 4, Cécile Rabrait2, Olivier Beuf1

                                1Université de Lyon; CREATIS; CNRS UMR 5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Villeurbanne, France; 2Clinical Science Development Group, General Electric Healthcare, Buc, France; 3Hospices Civils de Lyon; Département d’imagerie digestive; CHU Edouard Herriot, France; 4Centre Léon Bérard - Centre de Lutte contre le Cancer, France

 

To reduce RF-induced heating, standard passive RF traps are known to be efficient. Novel miniaturized RF traps are as efficient as standard ones for this purpose. Furthermore, it is demonstrated that RF traps enable a restoration of the signal intensity pattern of the coil. It is thus possible to perform a MR endoscopy of deeper regions of the bowel (after left colonic flexure for instance) since the coaxial cable incorporating miniaturized RF traps now may be inserted through the rectum with limited discomfort for the patient.

                    1369.   EMF Exposure and Temperature Increase of Anatomical Pregnant Women Models Within a 3T RF Shimmed Birdcage.

                                Manuel Murbach1, Esra Neufeld1, Fraser JL Robb2, Niels Kuster1, 3

                                1ITIS Foundation, Zurich, Switzerland; 2GE Healthcare, Aurora, OH, United States; 3Swiss Federal Institute of Technology (ETH), Zurich, Switzerland

 

Our study investigates the effect of RF shimming at 3T on EMF exposure and subsequent temperature increases in pregnant women of different gestational periods. The effect of relative I-Q phases and amplitudes is investigated in terms of B1+ uniformity (CV(B1+)) and local SAR enhancements. For selected worst-case scenarios, thermal simulations &#8722; including local thermoregulation &#8722; estimate the potential temperature increase in the mother, amniotic fluid, and fetus. Preliminary results indicate a relatively low thermal load for the fetus (< 38°C) when considering local thermoregulation of the mother in the normal operating mode.

                    1370.   A System for Calibrated Measurements of RF Electromagnetic Fields Inside a Clinical MR Scanner

                                Gerd Weidemann1, Isabela Frese1, Frank Seifert1, Antonino Mario Cassara'1, Werner Hoffmann1, Bernd Ittermann1

                                1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

 

For accurate and complete SAR assessment of an RF coil all E  and B field components are required. A system for the calibration of fiber optic time-domain E1 and B1 field sensors using an MR compatible TEM cell and the MR scanner itself was developed. The complex field amplitudes of E1, B 1+ and B1 were reliably measured in an ASTM body phantom equipped with provisions for internal and external field sensors. Utilizing the body coil of a clinical 3 T scanner, the measurements are used to evaluate the accuracy of EMF simulations.

                    1371.   Transmitted Power from a Tx/Rx Birdcage Coil to Nearby Conductors in Air and in Gel

                                Zoltan Nagy1, 2, Aaron Oliver-Taylor3, Andre Kuehne4, 5, Nikolaus Weiskopf1

                                1Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom; 2Laboratory for Social and Neural Systems Research, University of Zürich, Zürich, Switzerland; 3Institute for Women's Health, University College London, United Kingdom; 4Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria; 5MR Center of Excellence, Medical University of Vienna, Austria

 

Tx/Rx birdcage head coils are often considered safe for patients with abdominal implants but whether such practice is indeed safe has not been tested systematically. We used radio frequency B/E field probes to investigate the transmitted power through air and conductive gel by a Tx/Rx coil in a 3T scanner. We could detect significant levels of both fields at distances up to 50 cm from the Tx/Rx coil. These findings were confirmed with simulations. Preliminary heating results around straight and looped wires did not result in significant temperature elevation but this may be due to the insensitivity of the “implants”.

                    1372.   Determination of In-Vivo Temperature Rise and Gradient Induced Voltage During MRI of Cut Sacral Neuromodulation Leads

                                John Nyenhuis1, John Welter2

                                1Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States; 2Neuromodulation, Medtronic, Minneapolis, MN, United States

 

In-vitro tests and numerical simulations were made to determine the in-vivo temperature rise and during MRI of cut Neuromodulation leads (Medtronic 3889 and 3093) which were retained in-vivo after being used for treatment of urinary incontinence in women.  The overall method follows the procedure described in ISO-IEC 10974. For retained lead length of 7-cm, maximum temperature rise for whole body SAR of 2 W/kg was 2.4 C at 1.5T and 3.7 C at 3T. Rises at the cut exceeded those at the electrode. These rises yield in-vivo temperature that is less than the maximum safe value for neurological tissues.

                    1373.   The Feasibility of Combined Magnetic Resonance Thermometry and Multiphysics Simulation to Evaluate RF Induced Heating of Metallic Devices

                                David C. Gross1, 2, Yu Ding2, Sergei Yushanov3, Jeff Crompton3, Alan Leewood4, Orlando P. Simonetti5, 6

                                1Biomedical Engineering, The Ohio State University, Columbus, OH, United States; 2Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; 3AltaSim Technologies, LLC, Columbus, OH, United States; 4MED Institute, Inc., West Lafayette, IN, United States; 5Cardiovascular Medicine , The Ohio State University, Columbus, OH, United States; 6Radiology, The Ohio State University, Columbus, OH, United States

 

RF induced heating is an important safety concern as the number of patients implanted with medical devices increases and the use of 3T MRI becomes more prevalent. We hypothesize that the combination of Magnetic Resonance Thermometry (MRT) and multiphysics simulation would provide a more accurate assessment of MR safety than current in vitro test methods, and could ultimately be used to evaluate RF induced heating of devices in vivo.  The purpose of this work is to evaluate the feasibility of this approach by comparing temperature probe measurements with MRT and multiphysics simulation of RF induced heating near a metallic device.

                    1374.   EM and Thermal Validation of a Numerical Elliptical Birdcage at 3T in the Presence of a Long Conductive Wire

                                Mélina Bouldi1, Jan M. Warnking1, 2

                                1Grenoble Institut des Neurosciences - UJF, Grenoble, Rhônes Alpes, France; 2Inserm U836, Grenoble, Rhônes Alpes, France

 

Understanding the risk of overheating in the presence of implants requires a rigorous simulation of experimental conditions. We have built a model of the whole body transmit coil in the Philips Achieva TX® system. The validity of that model was verified by comparing electromagnetic and thermal simulations to phantom experiments for an ASTM phantom alone and in presence of a long copper wire. RF fields are in good agreement. Local temperature variations show similar dynamics and amplitudes. Realistic temperature simulations, as opposed to SAR simulations, provide a metric directly comparable to experimental results and thus facilitate validation.

 

                    1375.   OSSARTE: An Open-Source Software for SAR and Temperature Estimation

                                Giuseppe Carluccio1, Josh Vega1, Christian Gonzalez-Capizzi2, David Greydanus1, Christopher Michael Collins1

                                1Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, United States; 2Oratory Prep School, Summit, NJ, United States

 

To ensure safe use of MRI it is desirable to estimate and limit the Specific energy Absorption Rate (SAR) averaged over the whole body, whole head, and the maximum SAR averaged over any 1 or 10g region in the body. Safety guidelines by the IEC recommend limits on the maximum values of both SAR and temperature. In this work, we present a useful open source software which includes tools to locally average SAR and to compute temperature increase with different methods, letting the user choose whether to prioritize accuracy or computation speed.

                    1376.   MR Safety of Magneto-Inductive Receivers

                                Richard Syms1, Khoonsake Segkhoonthod1, Ian Young1

                                1EEE Dept., Imperial College London, London, Middlesex, United Kingdom

 

Radio frequency heating may be induced when linear conductors are inserted in the body during MRI, due to electrical excitation of surface wave resonances. The effect occurs even when inserted lengths are short, due to the high RF dielectric constant of tissue. We have developed receivers for internal imaging using magneto-inductive waveguides, a form of transformer-segmented waveguide that can be realized in thin film form and mounted on a catheter. This paper presents accurate EM simulation using AWR Microwave Office designed to confirm RF safety. The results highlight the effect of heatshrink material on surface wave resonances and parasitic capacitances.

                    1377.   Online SAR Measurement Error in High Resolution Slice Accelerated 2D EPI

                                An T. Vu1, Edward Auerbach1, Kamil Ugurbil1, Essa Yacoub1

                                1University of Minnesota, CMRR, Minneapolis, MN, United States

 

Slice accelerated or multiband (MB) 2D EPI has recently enabled fast, high resolution, whole brain imaging. However, as MB factors, resolution, and brain coverage increase so do the temporal frequency modulations of the MB RF pulses. Such rapidly modulated RF pulses can result in SAR overestimation during online SAR monitoring resulting in prematurely aborted scans even when pre-calculated SAR levels are below (60-70%) the FDA limit. We show that recent methods for minimizing peak power can also reduce SAR measurement errors with little or no cost in TR or image quality – allowing MB acceleration gains to be more fully realized.

                    1378.   Accurate EM Modelling of a Not-Fully Accessible RF Body Coil at 3T for Quantitative SAR Investigations

                                Antonino Mario Cassara'1, Gerd Weidemann1, Frank Seifert1, Bernd Ittermann1

                                1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

 

Accurate electromagnetic modelling of RF transmit coils for MRI, e.g. for quantitative SAR assessments, can be difficult when not all coil details are directly accessible to the modelers. This is typically the case for commercial coils and most notably for the body coil of a clinical scanner. The present work illustrates the steps for the creation of an accurate model of a commercial 3 T body coil. Information provided by the manufacturer is merged with in-situ RF measurements on accessible ports and results from numerical simulations. The accuracy of this modeling is quantified comparing simulated and measured B1+ field maps in a extensive phantom study.

                    1379.   Eigen Matrix Approach in Coupled-Circuit Numerical Simulation of Eddy Currents in MRI Systems

                                Md. Shahadat Hossain Akram1, Yasuhiko Terada1, Keiichiro Ishi1, Katsumi Kose1

                                1Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan

 

In coupled-circuit simulation of eddy currents, system of differential equations is solved to get eddy currents transient responses in different domains at different locations. It is desirable to improve computational efficiency whenever possible. Implementing Eigen matrix techniques to solve this system of equations removes singularity problems totally and reduces calculation time to a large level. We have implemented this approach to analyze eddy currents for both open and large closed-bore MRI systems. We have also conducted FID measurement of eddy fields by NMR probe to verify our approach. We have found good agreement between simulation and experiment.

                    1380.   Comprehensive Analysis of Parallel Transmission Local SAR Errors Introduced by an Assumed Uniform Density Distribution

                                Andre Kuehne1, 2, Sigrun Goluch1, 2, Ewald Moser1, 2, Elmar Laistler1, 2

                                1Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; 2MR Center of Excellence, Medical University of Vienna, Vienna, Austria

 

In this work, the validity of the commonly made assumption of an isotropic tissue density (1000 kg/m³) for SAR calculations is investigated. SAR matrix Eigenvalues- and vectors of an 8-channel head array for 7T MRI are compared and a statistical analysis performed. It is found, that the simplified SAR distribution leads to an overestimation of local SAR by 11-12% on average.

                    1381.   Coil Evaluation Metrics

                                Jinfeng Tian1, Lance Delabarre2, J. Thomas Vaughan2

                                1CMRR - Dept. of Rad., U. of Minnesota, Minneapolis, MN, United States; 2CMRR - Dept. of Rad., U. of Minnesota, MN, United States

 

Several differing coil arrays at 3T and 7T were simulated and evaluated for B1+ efficiency relative to net input power, global SAR and local SAR to demonstrate the importance of normalizing efficiency in terms of both input power and SAR.  Large volume efficiency metrics are better for coils that have variation in the z-axis.

Traditional Poster

Gradients, Shims, Magnets & Field Monitoring

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1382.   A New Magnet Design for Field Cycling OMRI

                                Constantin Job1, Jean-Philippe Galons1, Diego Martin1

                                1Medical Imaging, University of Arizona, Tucson, AZ, United States

 

A custom-built low-inductance solenoid magnet enables the cycling of the magnetic field strength in the range from 0 to 4700 Gauss in less than 10 msec

                    1383.   A Finite-Difference Model for the Analysis of Acoustic Noise Generated by Gradient Coil Switching

                                Liyi Kang1, Zhifeng Chen1, Zhiqian Ye1, Feng Liu2, Ling Xia1

                                1Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, China; 2School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia

 

In this work, a force-vibration-noise model has been developed for the analysis of gradient switching induced acoustic noise in MRI. The acoustic model is based on the finite difference method, and it can quantitatively evaluate the acoustic noise produced by typical gradient switching procedure. With the Tikhonov regularization based optimization technique, new gradient coils are designed; compared with conventional coils, the new gradient coils offer excellent magnetic field linearity and the sound pressure level is decreased by about 10%.

                    1384.   generalized Measure to Assess Gradient Coil Performance

                                Feng Jia1, Gerrit Schultz1, Anna Masako Welz1, Frederik Testud1, Hans Weber1, Sebastian Littin1, Huijun Yu1, Jürgen Hennig1, Maxim Zaitsev1

                                1Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Baden-Württemberg, Germany

 

We present a general performance measure to assess all the gradient coils from the perspective of different purposes. A matrix coil is used to demonstrate this general performance measure.

 

                    1385.   Multi Physics Modeling of Eddy Current Vibration Damping in MRI Systems

                                Kishore Venkata Mogatadakala1, Ming Yao1, Sampath Telikicherla Kandala1, Longzhi Jiang1, Timothy Havens1

                                1Magnet and Gradient engineering, GE Health care, Florence, SC, United States

 

Vibration induced eddy currents generate magnetic field disturbance in MRI systems and degrade image quality (IQ). In this work, a multi-physics based finite element approach is presented to simulate mechanical vibration and eddy currents. Both simulation and test results indicate that the induced eddy currents play a significant role in attenuating the vibration response and corresponding field disturbance. In order to demonstrate the applicability of the developed technique to a complicated mechanical resonance mode,  simulation was performed on a locally deforming hollow cylinder and the results are presented with and without electromagnetic damping.

                    1386.   Measuring the Spatial Magnetic Field Gradients Within a Scanner Bore

                                Karlene M. Fraser1, 2, Elizabeth Morris3, Jonathan Ashmore4, Stephen Wastling2, Ruth O'Gorman4, 5, Gareth Barker2

                                1Neuroimaging, Maudsley Hospital, London, United Kingdom; 2Centre for Neuroimaging Sciences, King's College London, London, United Kingdom; 3Medical Engineering and Physics, King's College Hospital, London, United Kingdom; 4Neuroradiology, King's College Hospital, London, United Kingdom; 5Centre for MR Research, University Children's Hospital, Zurich, Switzerland

 

Manufacturers of medical implants and devices classify some as MR conditional, and specify maximum spatial magnetic field gradient (MFG) restrictions in G/cm or T/m. Measurements of the MF within the bores of a 1.5T and 3.0T HD.x, and two 3.0T MR750 MR scanners were obtained using a THM1176 Hall probe. Maximum spatial MFG calculated for the 1.5T and each 3.0T scanner was respectively over 400 G/cm and 700 G/cm, and approximately 1.5 and 2 times less that reported by the scanner manufacturer. Had the manufacturer’s measurements been restricted to the patient accessible area, our measurements may have been more comparable.

 

                    1387.   Faster Feedback Field Control Using Shim Pre-Emphasis

                                Yolanda Duerst1, Bertram J. Wilm1, Signe J. Vannesjo1, Benjamin E. Dietrich1, Simon Gross1, David O. Brunner1, Thomas Schmid1, Klaas P. Pruessmann1

                                1ETH Zurich, Zurich, ZH, Switzerland

 

Real-time field feedback as implemented previously assumed instantaneous and uncoupled shim responses. The violation of this assumption by the real system leads to distortions in the feedback loop. The current work shows the implementation of self-term pre-emphasis for decreasing the shim response time and cross-term pre-emphasis in order to decouple the individual channels. This allows for a faster response to changes in the target field pattern and enables faster and more stable field feedback.

                    1388.   Couple Electromagnetic and Neuronal Dynamics Simulation of Gradient Coil Switching Induced Nerve Stimulation

                                Ioannis Vogiatzis Oikonomidis1, 2, Esra Neufeld1, Johanna Wolf1, Deepika Sharma1, 3, Yngve Hamnerius2, Niels Kuster1, 3

                                1IT'IS Foundation, Zurich, Switzerland; 2Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden; 3Information Technology and Electrical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland

 

Nerve stimulation by rapidly switching gradient coils is a safety concern in MR. An EM and thermal simulation platform has been coupled with a neuronal dynamics modeling code, to investigate such interactions in realistic anatomical models. A locally temperature dependent variant of the SENN model, commonly employed for safety threshold assessment, has been developed. Modeling of sciatic nerve stimulation by gradient coil switching, considering the impact of RF birdcage coil induced heating, showed that the model anisotropy, the field variation along the nerve and local temperature have a relevant impact that can be studied using the coupled EM-neuron simulation platform.

                    1389.   Improved Magnetically Induced Torque Measurement for MRI Safety Testing

                                Fred Tam1, Peter Geng2, Simon J. Graham1, 3

                                1Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada; 2Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada; 3Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

 

Torque measurements for MRI safety testing are often qualitative, despite ASTM standard F2213-06 which prescribes a quantitative measurement method and apparatus. To facilitate quantitative measurement, practical improvements were made to this apparatus, including a calibration procedure for its torsion springs. The resulting apparatus has increased capacity and simplified construction, and its accuracy has been characterized. Calibration data reveal nonlinear behaviour, warning against naive use of the simple formula in F2213-06. Example usage of the apparatus shows a prototype tablet device for fMRI passes F2213-06 criteria.

                    1390.   k-T-Calibration Improves Continuous Field Monitoring for Image Reconstruction

                                Benjamin E. Dietrich1, Bertram J. Wilm1, David O. Brunner1, Yolanda Duerst1, Christoph Barmet1, 2, Klaas P. Pruessmann1

                                1Institut for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Skope Magnetic Resonance Technologies, Zurich, Switzerland

 

By means of NMR probe based magnetic field monitoring, the spatio-temporal magnetic field evolution and hence k-space trajectory can be observed and used to improve image reconstruction. Continuous field monitoring based on time interleaved acquisition of sets of fast relaxing probes enables sequence independent monitoring over arbitrary durations without limitations on k-space range, but suffered so far under accumulated errors in the calculated trajectories due to violations of the assumption that the probes behave like point sources. The presented k-space and time domain calibration method addresses these problems and enables continuous monitoring for image reconstruction.

                    1391.   Mapping and Correcting Respiration-Induced Field Changes in the Brain Using Fluorine Field Probes

                                Mads Andersen1, 2, Kristoffer Madsen1, Lars Hanson1, 2, Vincent Boer3, Tijl van der Velden3, Dennis Klomp3, Joep Wezel4, Matthias van Osch4, Maarten Versluis4

                                1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; 2Biomedical Engineering Group, DTU Elektro, Technical University of Denmark, Kgs. Lyngby, Denmark; 3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 4C.J. Gorter center, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

 

Breathing induced dynamic B0 field perturbations in the head degrade image and spectral quality. It has recently been proposed to continuously stabilize the magnetic field by real-time updating of the shim fields, based on synchronous field measurements with external probes. A thorough analysis of how accurate such field measurements outside the head can reflect the spatially varying dynamic fields inside the head is currently lacking. We present such an analysis and see that 14 external field probes reflect the field in the head sufficiently well so it can be significantly stabilized.

                    1392.   Design Methods for Magnetic Resonance Based Field Monitoring Devices

                                Wieland A. Worthoff1, Stefan Schwan1, Arthur W. Magill1, Michael S. Poole1, N. Jon Shah1, 2

                                1INM - 4, Research Centre Jülich GmbH, Jülich, Germany; 2Department of Neurology, RWTH Aachen University, Aachen, Germany

 

Developing MR based field probes requires careful design, because a distorted local magnetic field within the sample droplet can lead to a significant reduction in signal fidelity. By simulating the local field variations due to the susceptibility of the field probe itself, we demonstrate a novel approach to acquiring appropriate design parameters in order to optimise the performance of new probe prototypes. We compare our numerical results with experimental data in order to verify and explore the capabilities of the simulation.

                    1393.   Hybrid Digital Phase-Locked Loop and Moving Average Filtering Improves SNR in Spatio-Temporal Field Monitoring

                                Yu-Chun Chang1, 2, Martin Eschelbach1, Klaus Scheffler1, Anke Henning1, 3

                                1Max Planck Institute of Biological Cybernetics, Tuebingen, Baden-Wuerttemburg, Germany; 2Graduate School of Neural & Behavioural Sciences, University of Tuebingen, Tuebingen, Baden-Wuerttemburg, Germany; 3Institute for Biomedical Engineering, University and ETH Zurich, Switzerland

 

Recent spatio-temporal B0 field monitoring methods utilise an array of NMR probes to measure the dynamics of the B0 field. The B0 field is usually characterised by spherical harmonic coefficients which are obtained from the phase signals (or phase coefficients) of the probe FIDs.

A hybrid method is presented that uses a moving average filter in conjunction with a digital phase locked-loop filter to improve the SNR of the phase signals measured by the NMR probes.

This method takes advantage of the FID SNR to reduce the phase jitter in the phase signal. It is also easy to implement for real-time applications.

 

                    1394.   Noise Reduction of Impulse Response Function of the Encoding Fields Calculation

                                Frederik Testud1, Johanna S. Vannesjö2, Christoph Barmet2, 3, Klaas P. Pruessmann2, Jürgen Hennig1, Maxim Zaitsev1

                                1Medical Physics, Department of Radiology, University Medical Center, Freiburg, Germany; 2Institute for Biomedical Engineering, University and ETH  Zürich, Zürich, Switzerland; 3Skope Magnetic Resonance Technologies, Zürich, Switzerland

 

The Impulse Response function of the scanners’ Encoding Fields (IREFs) allows improving the scanners’ preemphasis or the image reconstruction by predicting the encoding trajectory. The impulse response function was assessed by mean of magnetic field monitoring  where  the field evolution of triangular-shaped waveforms were used as inputs. The IREFs need to be low-pass filtered to reduce high-frequency noise. We propose to achieve this by obtaining the field probes’ phase derivative using the Savitzky-Golay filter and to use the discrete test waveform for IREF calculation. The repetition number can be potentially reduced by the proposed improvements in the impulse response calculation.

                    1395.   3D-Printed Geometric Distortion Correction Phantom for MRI

                                David W. Holdsworth1, 2, Matthew G. Teeter1, 2, Jaques S. Milner2, Steven I. Pollmann2, Maria Drangova, 23

                                1Department of Surgery, Western University, London, Ontario, Canada; 2Robarts Research Institute, London, Ontario, Canada; 3Department of Medical Biophysics, Western University, London, Ontario, Canada

 

Accurate correction of geometric distortion is increasingly important for MRI applications in image-guided intervention. Advances in 3D printing have made it possible to fabricate structures with three-dimensional features that facilitate automated analysis of geometric distortions. We describe the fabrication of a plastic structure comprised of 4.5 mm beads, supported by 1.5 mm struts at 13 mm nominal spacing, which is immersed in a tissue-mimicking liquid. Automated analysis produces a point cloud of fiducial locations and a vector map of distortion.  MRI imaging at 3T demonstrates the ability to determine average local distortions of ±0.53 mm, over a 500 ml volume.

Traditional Poster

PET-MRI Engineering & Methods

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1396.   Validation of a PET-Derived Respiratory Signal by Comparison with an MRI Pencil-Beam Navigator Signal in Simultaneous PET/MR

                                Richard Manber1, David Atkinson1, Anna Barnes2, Brian Hutton1, Celia O'Meara2, Sebastien Ourselin1, Simon Arridge1, Kris Thielemans1

                                1University College London, London, United Kingdom; 2University College London Hospital, London, United Kingdom

 

Respiratory gating in PET imaging is common practice to correct for motion. It has previously been shown that a respiratory signal can be extracted from PET list-mode data using Principal Component Analysis (PCA). We demonstrate the validity of this signal by showing a strong correlation with the ‘gold-standard’ MRI navigator signal, simultaneously acquired on 9 patients with a range of PET tracers, and by showing comparable PET gating results based on the PET and MRI derived respiratory signals respectively. Finally we show improvements in image sharpness of ‘motion corrected’ images, formed by warping and combining gates.

                    1397.   Probabilistic Atlas-Based Generation of Continuous-Valued Attenuation Correction Maps for Hybrid MR-PET Imaging

                                Kevin T. Chen1, 2, David Izquierdo-Garcia2, Clare Poynton2, Daniel B. Chonde2, 3, Ciprian Catana2

                                1Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States; 2A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States; 3Biophysics, Harvard University, Boston, MA, United States

 

We have implemented a method of generating continuous-valued attenuation coefficient maps for PET data correction in hybrid MR-PET scanners. This method combines atlas coregistration along with a trained classifier to provide information about subject local anatomy.

                    1398.   Improvement and Evaluation in PET Performance of 16-Channel Receive Anterior Array Coils for 3T Simultaneous PET/MR Scanner

                                Yun-Jeong Stickle1, Jianhua Yu2, Tae-Young Yang1, Sahil Bhatia1, Dmitriy V. Londarskiy1

                                1GE Healthcare, Aurora, OH, United States; 2GE Healthcare, Waukesha, WI, United States

 

The purpose of this study was to develop and evaluate the novel coil designs with new materials adopted to reduce the coil impact on PET image quality. We developed a new plastic-free 3T 16-channel flexible anterior array (AA) RF coil with V0 flammability rating and biocompatibility (PET/MR prototype AA2) for torso and cardiac imaging and validated the PET performances for a GE conventional AA coil and two improved PET/MR prototype coils. The results show a 48% and a 79% average sensitivity loss improvement on PET/MR prototype AA1 coil and PET/MR prototype AA2 coil, respectively, from GE conventional AA coil.

                    1399.   Whole Body RF Coil Design for a Simultaneous PET-MR System

                                Saikat Saha1

                                1GE Healthcare, GE, Waukesha, WI, United States

 

In conventional whole body RF transmit coils, various RF components such as diodes, capacitors, inductors, cables etc. are placed throughout the coil for optimal MR performance. If such components are placed in the FOV of the PET detector in a simultaneous PET/MR system, they will scatter some of the PET signals (511keV annihilation photons), affecting image quality. To address this problem we have created a “zero PET attenuation” whole body transmit/receive coil with minimal use of high density RF components. We present design and performance for the resulting body coil as implemented in our 3.0T simultaneous PET/MR system.

                    1400.   A Low PET Attenuation Transmit-Receive Head Coil for Simultaneous PET and MR Spectroscopy

                                Gillian Haemer1, 2, David Faul3, Thomas Koesters, 14, Kimberly Jackson1, Oded Gonen1, Graham Wiggins1

                                1The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States; 2The Sackler Institute for Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States; 3Siemens Medical Solutions, New York, NY, United States; 4Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, United States

 

In order to allow for simultaneous PET and MR Spectroscopic imaging (MRSI) on a PET/MR Hybrid system, RF coil designs must be MR efficient, transmit-receive capable, and provide low PET attenuation. We present a birdcage coil design based on these requirements, which provides sufficient efficiency for MRSI, while creating minimal attenuation. We compare the MR efficiency of this coil to an MR Instruments TEM coil, and the PET attenuation to the attenuation-minimized receive-only head coil provided with the PET/MR system, and find that this design provides comparable MR efficiency and superior attenuation minimization.

                    1401.   Combining MRI with PET for Partial Volume Correction Improves Image-Derived Input Functions in Mice

                                Eleanor Evans1, David Izquierdo Garcia2, Guido Buonincontri1, Carmen Methner3, Rob C. Hawkes1, Thomas Kreig3, T. Adrian Carpenter1, Stephen J. Sawiak1, 4

                                1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom; 2Athinoula A. Martinos Centre for Biomedical Imaging, Harvard University, MA, United States; 3Department of Medicine, University of Cambridge, Cambridge, United Kingdom; 4Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom

 

Kinetic modelling in Positron Emission Tomography (PET) allows metabolic measures to be obtained, but requires the tracer arterial input function (AIF). Blood sampling to acquire the AIF is prohibitive in mice due to low blood volumes. Image-derived AIFs are therefore preferred, although their extraction from blood vessels is hampered by low spatial resolution (~1.5-2mm). We found that using an AIF extraction method which employed partial volume correction (PVC) in the mouse heart was crucial for deriving accurate AIFs and gave best results when ROIs were based on MRI data rather than PET data.

                    1402.   Evaluation of MR Compatibility of a SiPM-Based PET Scanner for Simultaneous PET/MR Studies Operating at Animal 7-T MR Scanner

                                Guen Bae Ko1, Daehong Kim2, Hyun Suk Yoon1, Min Sun Lee1, In Chan Song3, Jae Sung Lee1

                                1Department of Nuclear Medicine, Seoul National University, Seoul, Korea; 2Molecular Imaging and Therapy Branch, National Cancer Center, Goyang, Gyeonggi, Korea; 3Department of Radiology, Seoul National University, Seoul, Korea

 

Here, we¡¯d like to report relevant influences of novel SiPM-based PET scanner on MR images at ultra-high magnetic field. Several MR image including FSE, SE, GRE, 3D SPGR, and EPI were evaluated with a 7-T MRI scanner and 35-mm-inner-diameter mouse body transceiver coil. The experimental results show that the PET insert unit affects only minor effect on MR images that can be ensured for preclinical evaluation. It was also proved that to perform multi-functional study of PET and functional MRI using our PET insert unit is possible.

                    1403.   Bayesian Segmentation of Dual-Echo UTE Images for PET/MR Attenuation Correction

                                Gaspar Delso1, Michael Carl1, Florian Wiesinger2, Martin Hüllner3, Patrick Veit-Haibach3

                                1Global MR Applications & Workflow, GE Healthcare, Waukesha, WI, United States; 2GE Global Research, Munich, Germany; 3University Hospital, Zurich, Switzerland

 

MR-based attenuation correction is a critical component of integrated PET/MR scanners. This is generally achieved by segmenting MR images into a set of tissue classes with known attenuation properties (e.g. bone, fat, soft tissue, lung, air). Ultra-short echo time (UTE) sequences capable of imaging tissues with short T2* times (<1 ms) have been proposed in the past as a means to locate bone tissue1-4. In this study, we used tri-modality PET/CT+MR data from oncology patients to develop an improved classification algorithm for the localization of bone tissue in the head and neck area.

                    1404.   Integrated PET/MR: Phantom Studies Towards Radiotracer Dose Reduction

                                Mark Oehmigen1, Susanne Ziegler1, Björn W. Jakoby2, 3, Harald H. Quick1

                                1Institute of Medical Physics, University of Erlangen-Nuremberg, Erlangen, Germany; 2Siemens Healthcare Sector, Erlangen, Germany; 3University of Surrey, Guildford, Surrey, United Kingdom

 

In integrated PET/MR hybrid imaging data acquisition times per bed position are comparatively longer than in PET/CT imaging.  Increasing PET data acquisition times may allow decreasing the injected radiotracer dose while maintaining image quality.

 

All measurements were performed on an integrated PET/MR whole-body hybrid system using the NEMA image quality phantom. PET images were acquired with doubled time but halved activity.

 

The images acquired at different tracer activity levels and acquisition times show no visible difference in quality and only small quantitative measurable changes.

Longer PET acquisition time in PET/MR enable the reduction of the administered PET tracer activity.

                    1405.   Wireless MR Active Marker Based PET Motion Correction in Simultaneous Brain MR-PET

                                Chuan Huang1, Jerome L. Ackerman2, Yoann Petibon1, Marc D. Normandin1, Georges El Fakhri1, Jinsong Ouyang1

                                1Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States; 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

 

Recently, wireless active markers have been used in head motion tracking/correction in brain MRI due to its improved patient safety, ease-of-use and simpler manufacturing. Head motion is even more a problem in brain PET since dynamic brain PET can last more than an hour. Furthermore, anesthesia is often used to keep animals still during brain PET acquisitions, but many studies showed that anesthesia can also perturb the neurological process under study.

Simultaneous MR-PET is a novel hybrid modality generated substantial interest in recent years. Complementary information of the brain from PET and MR can be simultaneously obtained. This new modality also opens the possibility to use MR active marker derived motion information for PET motion correction.

In this work, we demonstrate in phantom and non-human primate studies the use of wireless active markers to track head motion and incorporating the measure motion information in the list-mode PET reconstruction to obtain PET images without motion artifacts in simultaneous MR-PET.

 

                    1406.   Quantitative Evaluation of the Short-Lived Eddy Currents in Shield Boxes of the Novel MRI Head Coil Integrated with PET Detectors

                                Mikio Suga1, 2, Takayuki Obata2, Kodai Shimizu1, Fumihiko Nishikido2, Atsushi Tachibana2, Hideto Kuribayashi3, Iwao Nakajima4, Yoshihiko Kawabata4, Taiga Yamaya2

                                1Chiba University, Chiba, Japan; 2National Institute of Radiological Sciences, Chiba, Japan; 3Siemens Japan K. K., Tokyo, Japan; 4Takashima Seisakusho Co., Ltd., Tokyo, Japan

 

We are developing a new PET/MRI system in which PET detectors are closely located at the MR head coil. To reduce electromagnetic interaction between PET detectors and MRI coil, the PET detectors are covered with conductive shield boxes. In this study, we quantitatively evaluated the secondary magnetic field induced by short-lived eddy currents in shield boxes and the effect of slits in shield boxes. The results showed that the secondary magnetic field induced by the shield boxes without slits was not negligible for EPI. We can observe the eddy current reduction effect by making a slit in a shield box.

                    1407.   An MR-PET Phantom for Studies of the Male Pelvis

                                Philipp Mann1, Armin Runz2, Martin Schaefer3, Peter Bachert1

                                1Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany; 3Department of Radiopharmaceutical Chemistry, German Cancer Research Center, Heidelberg, Germany

 

An MR-PET phantom for evaluation of studies of the male pelvis was designed. Hollow components mimicking thigh bone, bladder, and prostate were built using 3D printing technique. Experimental tests were performed with 68Ga-PET, 1H-MRI, and 1H spectroscopic imaging.

                    1408.   Direct Evaluation of MR-Derived Attenuation Correction Maps for PET/MR of the Mouse Myocardium

                                Eleanor Evans1, Guido Buonincontri1, Rob C. Hawkes1, Richard E. Ansorge2, T. Adrian Carpenter1, Stephen J. Sawiak1, 3

                                1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom; 2Department of Physics, University of Cambridge, Cambridge, United Kingdom; 3Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom

 

Attenuation correction (AC) must be applied to provide quantitative measurements of Positron Emission Tomography (PET) tracer activity concentrations. The gold standard AC method involves passing a transmission source around the subject and surrounding scanner equipment. Due to the limited space in PET/MR scanners, MR-derived AC (MRAC) must be used instead.  This is problematic as MR signals are not directly related to the amount of gamma radiation absorbed. By comparing to gold standard transmission scans, we found a single tissue region MRAC segmentation approach, derived from whole body MRI, provided accurate myocardial SUV values in mice.

                    1409.   Influence of Patient Motion in Bone Tissue Maps Obtained with Ultra-Short Echo Time MR

                                Patrick Veit-Haibach1, Michael Carl2, Mehdi Khalighi2, Florian Wiesinger3, Konstantinos Zeimpekis1, Gaspar Delso2

                                1University Hospital, Zurich, Switzerland; 2Global MR Applications & Workflow, GE Healthcare, WI, United States; 3GE Global Research, Munich, Germany

 

Accurate mapping of the attenuation properties of patient tissue is instrumental for quantitative positron emission tomography (PET). In hybrid PET/MR scanners, this can be achieved using dedicated MR images to identify tissue classes of known attenuation (e.g. fat, lung, air). For the particular case of bone tissue, standard sequences are not adequate due to the fast T2* relaxation time. Ultra-short echo time (UTE) sequences have been reported to provide adequate bone tissue identification for the purposes of PET attenuation correction. These sequences do, however, require acquisition times in the order of 2 to 5 minutes to cover a typical PET station. Such long acquisition times increase the probability of patient movement occurring during the acquisition. In this study, we analyze the artifacts introduced by patient motion on the bone maps obtained with UTE.

Traditional Poster

Applications of Ultra-High Fields

Traditional Poster Hall     Monday 16:30-18:30                                                                     

                    1410.   Accelerated Multiplexed-EPI with PSF-Based Distortion Correction at 9.4T

                                Seong Dae Yun1, N. Jon Shah1, 2

                                1INM - 4, Research Centre Jülich GmbH, Jülich, Germany; 2Department of Neurology, RWTH Aachen University, Aachen, Germany

 

The relatively high imaging speed of EPI has led to its widespread use in dynamic MRI studies. The performance of the EPI can be improved by combining it with in-plane acceleration techniques such as multi-shot, parallel MRI and EPI with Keyhole (EPIK). For even faster volumetric acquisition in EPI, the multiplexed-EPI (M-EPI) method has also been presented (Feinberg et al.). This study i) verifies the use of the in-plane acceleration techniques on the M-EPI at 9.4T and ii) quantitatively assesses the performance of each imaging method. Lastly, the robust removal of geometric distortions is demonstrated with the PSF-based correction method.

 

                    1411.   High-Resolution MR Angiography at 7T: Detection of Perforating Arteries of the Anterior Communicating and Distal Middle Cerebral Arteries

                                Taisuke Harada1, Yuiko Sato2, Takamasa Nanba2, Takahiro Kouji2, Takaaki Beppu2, Tsuyoshi Matsuda3, Hiroyuki Kabasawa3, Fumio Yamashita1, Ikuko Uwano1, Kohsuke Kudo4, Kuniaki Ogasawara2, Makoto Sasaki1

                                1Ultra-High Field MRI, Iwate Medical University, Morioka, Iwate, Japan; 2Neurosurgery, Iwate Medical University, Morioka, Iwate, Japan; 3Global Applied Science Laboratory, GE Healthcare, Hino, Tokyo, Japan; 4Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, Japan

 

Minute perforating arteries such as the hypothalamic branch of the subcallosal artery and the long insular artery, which can cause severe neurological complications when injured during surgery, have not been visualized using imaging modalities including magnetic resonance angiography (MRA) at 3 Tesla or below. We revealed that high-resolution MRA at 7T, particularly with a magnetization transfer contrast pulse, can readily visualize these arteries and their relationship with surrounding structures. This technique may contribute to avoiding complications of surgery on aneurysms at the anterior communicating artery and tumors in the insulo-opercular regions.

                    1412.   Clinical Application of 7T MRI for Deep Brain Stimulation (DBS) Surgery and Postoperative Programming

                                Yuval Duchin1, Guillermo Sapiro2, Shai Chazin1, Kenneth Baker3, Jon McIver4, Jerrold Vitek3, Noam Harel1, 5

                                1Radiology / CMRR, University of Minnesota, Minneapolis, MN, United States; 2Electrical and Computer Engineering, Duke University, Durham, NC, United States; 3Neurology, University of Minnesota, Minneapolis, MN, United States; 4Neurosurgery, Regions Hospital, St. Paul, MN, United States; 5Neurosurgery, University of Minnesota, Minneapolis, MN, United States

 

Deep brain stimulation (DBS) surgery has emerged as a powerful neuromodulation clinical therapy. Current standard clinical imaging protocols do not have sufficient resolution and/or SNR to delineate brain structures relevant to DBS surgery.

Structural images acquired at 7T exhibit rich informational content with potential utility for clinical applications. Here we utilized 7T images to create patient-specific anatomical models to enhance pre-surgical DBS targeting as well as post-surgical visualization of the DBS lead position and orientation, including its four individual contacts. These new visualization capabilities will enhance and improve DBS outcomes.

 

                    1413.   Imaging the Human Brainstem at 7 Tesla Using Multi-Modal Echo-Planar Imaging

                                Florian Beissner1, Jonathan R. Polimeni1, Marta Bianciardi1, Ville Renvall1, 2, Cornelius Eichner1, 3, Vitaly Napadow1, Lawrence L. Wald1, 4

                                1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 2Brain and Mind Laboratory, Aalto University, Finland; 3Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 4Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

 

The human brainstem is a notoriously difficult structure to study with MRI. Here, we present an entirely EPI-based approach that allows for the acquisition of T2*-weighted functional, T1-weighted structural as well as diffusion-weighted images at a resolution of 1.2 mm isotropic. Due to matched voxel size and distortion, BOLD and DTI images can be normalized to MNI space applying transformation parameters estimated from the T1-weighted EPI image, minimizing coregistration errors. Using masked independent component analysis we were able to detect brainstem nuclei at the single-subject level and to depict their functional connectivity to the rest of the brain.

                    1414.   GRE Reference Scan for Robust Reconstruction of High Resolution Slice and In-Plane Accelerated 2D GE EPI at 7T

                                An T. Vu1, Steen Moeller1, Edward Auerbach1, Kamil Ugurbil1, Essa Yacoub1

                                1University of Minnesota, CMRR, Minneapolis, MN, United States

 

High temporal, high spatial resolution 2D EPI requires acceleration along both the in-plane phase encode (e.g. GRAPPA) and slice directions (e.g. multiband, MB). For such acquisitions, image quality is particularly sensitive to motion during segmented multi-shot reference scans, which is lengthened by a factor of MB. We propose the GRE flash for in-plane unaliasing of high resolution slice accelerated 2D EPI. With this technique, motion during reference scan related artifacts and reconstruction noise are significantly reduces especially at higher spatial resolutions (<1.25mm isotropic). For 0.9mm data, we found SNR to improve by 40% over conventional segmented EPI reference scans.

                    1415.   Comparison Between Single-Shot Diffusion Weighted Methodologies at 3 and 7 Tesla on Brain Volunteers

                                Eddy Solomon1, Noam Ben-Eliezer2, Daniel K. Sodickson2, Lucio Frydman1

                                1Chemical Physics, Weizmann Institute of Science, Rehovot, Israel; 2Bernard and Irene Schwartz Center for Biomedical Imaging, Radiology, New York University School of Medicine, New York, NY, United States

 

The potential of a recently proposed single-shot methodology, SPatio-temporal ENcoding (SPEN), was explored towards brain diffusion imaging on a 7T whole-body scanner. To better evaluate this imaging performance, studies were repeated at 3T, and done in parallel with diffusion-weighted SE-EPI scans. In both axial and coronal scans, SPEN evidenced a higher robustness to overcome the B0-inhomogeneities that arise particularly at 7T and also at 3T. The diffusion measurements of the brain showed fair agreement between both acquisitions methods, even despite the slight differences evidenced between the 3T and 7T ADC maps.

                    1416.   Clinical Relevance of EPI Distortion Correction in Presurgical fMRI at 7T

                                Barbara Dymerska1, Florian Fischmeister1, 2, Alexander Geissler1, 2, Eva Matt1, 2, Siegfried Trattnig1, Roland Beisteiner1, 2, Simon Robinson1

                                1Departement of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; 2Department of Neurology, Medical University of Vienna, Vienna, Austria

 

FMRI is increasingly being applied in presurgical planning. Although ultra-high field provides higher tSNR it also induces stronger geometric distortions. We investigate the clinical relevance of distortion correction using B0 field maps.  Analysis of eight patients performing hand and chin tasks at 7T revealed that neglecting geometric distortions could lead to the misidentification of the central sulcus. Moreover, the distance between the pathology and activation could be wrongly estimated, which could affect decisions about resection margins. It is therefore important to correct for distortions in patient fMRI data to ensure that reliable clinical decisions are made.

 

                    1417.   Feedback Field Control in 3D T2* Imaging at 7T

                                Yolanda Duerst1, Michael Wyss1, Bertram J. Wilm1, Benjamin E. Dietrich1, Simon Gross1, David O. Brunner1, Thomas Schmid1, Klaas P. Pruessmann1

                                1ETH Zurich, Zurich, ZH, Switzerland

 

Field changes due to respiratory motion disturb T2*-weighted imaging not only in 2D acquisition but also in 3D. Due to the inherent averaging of 3D scans, artifacts were not as pronounced as in 2D in the upper parts of the brain but manifested as a general blurring of the image. However, 3D T2*-weighted scans showed strong ringing artifacts around cavities as well as intensity modulations in the cerebellum. By using real-time field feedback breathing induced spatiotemporal field changes could be corrected and the observed artifacts were strongly reduced.

                    1418.   Effect of Embedding Media on Post-Mortem MRI of Formalin-Fixed Brain Tissue at 7.0 T

                                Petr Dusek1, 2, Vince Istvan Madai3, Matthias Dieringer4, 5, Fabian Hezel4, Thoralf Niendorf4, 5, Jan Sobesky3, 5, Radoslav Matej6, Jens Wuerfel1, 7

                                1Institute of Neuroradiology, University Medicine Goettingen, Goettingen, Germany; 2Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic; 3Department of Neurology and Center for Stroke Research Berlin (CSB), Charité-Universitaetsmedizin, Berlin, Germany; 4Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany; 5Experimental and Clinical Research Center (ECRC), Charité-Universitaetsmedizin and Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany; 6Department of Pathology and Molecular Medicine, Thomayer Teaching Hospital, Praha, Czech Republic; 7NeuroCure Clinical Research Center, Charité-Universitaetsmedizin, Berlin, Germany

 

It is well known that formalin fixation of post-mortem material affects its contrast mechanism and MR characteristics. It is however not clear how these parameters and image quality are affected by the medium in which is the post-mortem material embedded during scanning. Our goal was to compare different embedding media (deuterium oxide (D2O), formalin, low-melting temperature agarose and  phosphate-buffered-saline) for post-mortem MRI and ascertain which gives the best signal-to-noise ratio and contrast results. Also, we wanted to find out whether embedding medium has influence on signal intensity of formalin fixed brain slices. We employed T2 mapping, T1 mapping, T2* mapping, MP-RAGE and TIRM sequences. The results for all embedding media are shown.

 

                    1419.   Two-Voxel Hadamard Encoded Semi-LASER Spectroscopy for in Vivo MRS at Ultra-High Field

                                Adam Berrington1, Peter Jezzard1, Stuart Clare1, Uzay Emir1

                                1FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom

 

Large chemical shift displacement errors in MRS at ultra-high field can limit SNR and lead to spurious J-evolution across the VOI. Multi-voxel approaches are particularly susceptible to poor localisation, resulting in signal bleed between voxels. By incorporating two-voxel Hadamard encoding with a semi-LASER localisation sequence at 7T, we show that both CSD and inter-voxel bleeding can be minimised. Demonstrating this method in vivo on 4 volunteers, we are able to obtain highly resolved spectra with efficient water suppression simultaneously from both voxels. Metabolites such as GABA, Glu, Lac and Ins can be reliably determined with the method.

                    1420.   Laminar Features of Cortical Natural Sound Processing in Humans

                                Michelle Moerel1, Federico De Martino2, An T. Vu1, Valentin G. Kemper2, Kamil Ugurbil1, Elia Formisano2, Essa Yacoub1

                                1Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 2Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands

 

We present preliminary data showing the feasibility of examining frequency preference based on natural sounds across cortical depths. The use of natural sounds will enable the exploration of laminar tuning to features beyond frequency, such as temporal and spectral modulations.

                    1421.   Brain Imaging with 7T Vs. 9.4T: A Direct Comparison of MR Parameters and SNR

                                Rolf Pohmann1, Klaus Scheffler1, 2

                                1Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany; 2Department of Bioimaging, University of Tübingen, Germany

 

Increasing the magnetic field strength beyond 7 T is expected to result in an increase of SNR, but this may be limited by the more unfavorable relaxation times, the B1 inhomogeneity and the more difficult coil design. Here, SNR and MR parameters are compared for field strengths of 3 T, 7 T and 9.4 T. After correction for flip angle variations, a strong gain in SNR of almost a factor of two is found when going from 7 T to 9.4 T, but increasing inhomogeous B1-fields and shorter T2* demand for improved imaging techniques.

                    1422.   Imaging Oculomotor Subsystems in the Cerebellum at 7 Tesla

                                Melissa A. Batson1, 2, Natalia Petridou3, Dennis WJ Klomp3, Maarten A. Frens2, Sebastian FW Neggers1

                                1Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, Netherlands; 2Neuroscience, Erasmus Medical Center, Rotterdam, Zuid Holland, Netherlands; 3Imaging Division, UMC Utrecht, Utrecht, Netherlands

 

Using an innovative combination of high-density multi-unit surface coils, dual transmission, ROI shimming and 3D parallel imaging at 7T it is possible to clearly image the deep and complex structures and functions of the cerebellum during various motor tasks, including oculomotor tasks requiring eye tracking. Results demonstrate superior functional localisation within both oculomotor vermis and, when a cognitive component is present, in both CrusI and CrusII. In addition, BOLD signal strengths vary with the magnitude of difficulty of the task for both motor and cognitive components in a manner consistent with the changes in firing patterns observed in animal cerebellum.

                    1423.   The Optimization of B1 Insensitive T1 Weighted MP2RAGE Sequence at High Field.

                                Wanyong Shin1, Sehong Oh1, Tobias Kober2, 3, Mark J. Lowe1

                                1Radiology, Cleveland Clinic, Cleveland, OH, United States; 2Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland; 3CIBM-AIT, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

 

Large spatial B1 inhomogeneities are observed at ultra-high magnetic field (=7T), which creates non-uniform signal intensity across an image volume. While MP2RAGE has shown the potential to minimize B1 variation, a long TR (>8s) is necessary to generate the high signal to noise ratio and contrast to noise ratio by providing the large dynamic contrast range. In this study, we optimize fast MP2RAGE parameters to generate T1 weighted contrast at 7T with 10% of image non-uniformity in brain tissues. A healthy subject was scanned with the optimized parameters according to different TRs at 7T and brain segmentation results were compared.

                    1424.   Localized Spectroscopy Without J-Modulation at Ultra High Field

                                Clark Lemke1, Uzay Emir1, Peter Jezzard1, Stuart Clare1, Jamie Near2

                                1FMRIB, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Douglas Institute, McGill University, Verdun, Quebec, Canada

 

In vivo quantification of coupled metabolites is hampered by J-modulation. J-modulation manifests as an echo time (TE) dependent modulation on the metabolite signal leading to increased signal loss over and beyond other relaxation processes. Short TE spectroscopy avoids the effects of J-modulation but is complicated by a broad baseline extending over the relevant frequency range. This baseline can lead to decreased accuracy of metabolite quantification. Here we present a localized metabolite quantification pulse sequence designed to remove J-modulation at long TE (<40 ms) to avoid baseline contamination.  The sequence (PRESS-JR) is presented with phantom measurements.

                    1425.   Functional ASL at 9.4 T – a Comparison Between Balanced SSFP and GRE-EPI Readout

                                Jonas Bause1, 2, Philipp Ehses3, 4, G. Shajan3, Klaus Scheffler3, 4, Rolf Pohmann3

                                1High-Field Magnetic Resonance , MPI for biological Cybernetics, Tuebingen, BW, Germany; 2Graduate Training Center of Neuroscience, International Max-Planck Research School, Tuebingen, BW, Germany; 3High-Field Magnetic Resonance, MPI for biological Cybernetics, Tuebingen, BW, Germany; 4Department for Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, BW, Germany

 

Functional ASL has a higher specificity and reproducibility than BOLD fMRI. However, the perfusion related signal is typically in the range of a few percent and the spatial and temporal resolution of arterial spin labeling imaging rather limited. ASL at ultra-high field can benefit from higher intrinsic SNR and increased longitudinal relaxation times. We investigated bSSFP and GRE-EPI as possible readout schemes for fASL studies at 9.4 T and were able to measure the first time stimulus evoked perfusion changes in the human motor cortex at this field strength.

                    1426.   Tractography of the Trigeminal Nerve Using 7T MRI

                                Christophe Lenglet1, Julien Sein1, Julian Tokarev, Andrew W. Grande2, Bharathi Jagadeesan3, Pierre-Francois Van de Moortele1

                                1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 2Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States; 3Department of Radiology, University of Minnesota, Minneapolis, MN, United States

 

We performed ultra high-field (7T) diffusion MRI and probabilistic tractography on the trigeminal nerve in a series of normal volunteers. We were able to reconstruct the detailed three-dimensional course of fiber pathways from individual divisions of the trigeminal nerve, as they travel within its ganglion and the nerve root to the brain stem. This information can be useful to better understand the etiology of Trigeminal Neuralgia, a poorly understood neurological disorder, which is characterized by extremely painful episodes of facial pain produced by routine stimuli like light touch.

                    1427.   Physiologic Noise at 7T: PESTICA for 3T Obtains Signals for Pulse and Respiration at Ultra-High Field

                                Erik Beall1, Mark Lowe1

                                1Imaging Institute, Cleveland Clinic, Cleveland, OH, United States

 

Physiologic noise in BOLD acquisitions is problematic for fMRI and connectivity analyses, and is an increasing problem at higher field strengths. There is one existing software package, PESTICA, that can obtain signals at 3T with the same periodicity as parallel monitored pulse and respiration signals and thus can be used in physiologic corrections. PESTICA uses spatial priors generated at 3T and we test PESTICA at 7T, finding promising results.

                    1428.   Quantitative Analysis of Lateral Geniculate Nucleus (LGN) in Glaucoma Using 7.0T MRI

                                Hye-Jin Jeong1, Jong-Yeon Lee2, Jong-Hwan Lee2, Sang-Han Choi1, Young-BO Kim1, Zang-Hee Cho1

                                1Neuroscience Research Institute, Gachon University, Incheon, Korea; 2Department of Ophthalmology, Gachon University Gil Hospital, Incheon, Korea

 

Glaucoma is characterized by progressive degeneration of retinal ganglion cells (RGC) and their axons. Recent neuroimaging studies in human glaucoma have demonstrated degenerative changes in the visual pathway of brain including lateral geniculate nucleus (LGN). However, a precise assessment of the LGN is still a technical challenge due to anatomic characteristics. Therefore, our aim was to investigate the LGN atrophy in patients with open-angle glaucoma using high-resolution 7.0 Tesla MR imaging and correlation with retinal nerve fiber layer (RNFL) thickness

 

                    1429.   High Spatial Resolution Ophthalmic MRI at 7.0 Tesla  in Healthy Subjects and in Patients with Intraocular Masses

                                Andreas Graessl1, Jan Rieger2, Soenke Langner3, Paul Krueger3, Oliver Stachs4, Michael Schwerter5, Max Muhle5, Thoralf Niendorf1

                                1Berlin Ultrahigh Field Facility (B.U.F.F.) , Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany; 2MRI.TOOLS GmbH, Berlin, Germany; 3University of Greifswald, Institute for Diagnostic Radiology and Neuroradiology, Greifswald, Germany; 4University of Rostock, Department of Ophthalmology, Rostock, Germany; 5Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany

 

100

                    1430.   High Resolution Bilateral Hip Joint Imaging at 7 Tesla

                                Jutta Ellermann1, Mikko Nissi2, 3, Dingxing Wang4, Sebastian Schmitter5, Peter Kollasch4, Pierre-Francois Van De Moortele5

                                1Department of Radiology, University of Minnesota, Minneapolis, MN, United States; 2Department of Orthopaedic Surgery, University of Minnesota, MN, United States; 3CMRR, MN, United States; 4Siemens Medical Solutions, MN, United States; 5CMRR, University of Minnesota, MN, United States

 

Recent availability of arthroscopic treatment options for young patients with femoroacetabular impingement has increased the importance of high-resolution hip MRI as a diagnostic tool. If left untreated, this condition can lead to premature osteoarthritis. Due to SNR gains, imaging the hip joints at 7 Tesla is expected to improve diagnostic precision by accurately assessing the state of the thin (1-2 mm) acetabular cartilage,.  7T data obtained with multichannel transmit RF and transmit B1 shim methods suggests that non-enhanced bilateral hip MRI at ultrahigh fields provide the necessary gains in contrast and resolution for accurate diagnostic evaluation of the acetabular cartilage.

                    1431.   En Route to Clinical Ultrahigh Field Musculoskeletal MR Using Multi-Purpose Transceiver RF Modules for Spine Und Shoulder Imaging at 7.0 T.

                                Andreas Graessl1, Soenke Langner2, Marko Hoehne3, Matthias A. Dieringer1, Thoralf Niendorf1, 4

                                1Berlin Ultrahigh Field Facility (B.U.F.F.) , Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany; 2University of Greifswald, Institute for Diagnostic Radiology and Neuroradiology, Greifswald, Germany; 3Helios Kliniken, Berlin-Buch, Germany; 4Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany

 

Given the limited availability of RF coils for MSK-MR and recognizing the versatile range of musculoskeletal MR applications this work pursues modular RF transceiver configurations which suite the geometrical needs of a broad spectrum of musculoskeletal anatomy. The applicability of the modular configurations tailored for spine and shoulder imaging is demonstrated in healthy subjects. The multi-purpose configurations afforded the acquisition of sub-millimeter spatial resolution images of the shoulder. The sensitivity of the modular spine TX/RX configuration facilitated a spatial resolution as low as (0.13x0.13x1) mm³ for 3D GRE. This resolution helped to depict small structures such as the facet joints.

                    1432.   In Vivo {1H}-13C NMR Spectroscopy of the Human Calf on a 7-T Whole-Body MR Tomograph

                                Tanja Platt1, Andreas Korzowski1, Peter Bachert1

                                1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Baden-Württemberg, Germany

 

13C NMR spectroscopy is applied to observe various metabolites in vivo, e.g. triacylglycerides (TAG). High field strengths and 1H spin decoupling enhance signal and information content of 13C NMR spectra. In this study high resolution 1H–decoupled 13C NMR spectra of the human calf were obtained on an experimental 7–T whole–body MR tomograph.

                    1433.   T1 and T2 Relaxation Times of the Human Calf at 7 Tesla

                                Anja M. Marschar1, Mathies Breithaupt1, Moritz C. Berger1, Armin M. Nagel1

                                1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

 

On 7 Tesla we measured the relaxation times T1 and T2 of the human calf with separate consideration of muscle tissue and subcutaneous fat tissue. A saturation recovery and spin echo sequence with non-equidistantly adapted TI and TE (that match to T1 and T2 respectively) was used to get a linear sampling on the magnitude axis. For comparison with lower field strength, all measurements were also carried out on a 3T scanner and are compared with literature.

                    1434.   Echo-Planar Spectroscopic 13C and 31P NMR Imaging of Human Calf Muscle in Vivo on a Whole–body 7-T MR Tomograph

                                Andreas Korzowski1, Tanja Platt1, Peter Bachert1

                                1Dept. of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Baden-Württemberg, Germany

 

In this study an echo–planar spectroscopic imaging (EPSI) technique was applied to obtain localized high–resolution in vivo 13C and 31P NMR spectra from human calf muscle on a whole–body 7–T MR tomograph. Fast spectroscopic imaging techniques such as EPSI where information from one spatial direction is simultaneously encoded with the spectral information reduce the measurement time strongly.

                    1435.   3D EPSI - Exploring the Potential of 3D Spectroscopic Imaging of the Prostate at 7 Tesla

                                Arjan D. Hendriks1, 2, Tijl A. van der Velden1, Mariska P. Luttje1, Vincent O. Boer1, Peter R. Luijten1, Dennis W.J. Klomp1

                                1Imaging Division, University Medical Center, Utrecht, Netherlands; 2Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

 

To guide prostate cancer treatment, it is important to know the aggressiveness of the prostate tumor in question. Magnetic Resonance Spectroscopic Imaging (MRSI) has great potential to determine this aggressiveness, especially considering current progress of ultra-high field MR systems in separating choline from polyamines. A 3D EPSI acquisition & reconstruction method was developed and compared with current 2D MRSI methods. Found is that high field three-dimensional spectroscopic imaging can be performed within the prostate, using an EPSI sequence, avoiding extended scan time.

                    1436.   En Route to Probing Human Myocardial Microstructure In Vivo Using Susceptibility Based MRI at 7.0 T

                                Till Huelnhagen1, Fabian Hezel1, Thoralf Niendorf1, 2

                                1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany; 2Experimental and Clinical Research Center, a joint cooperation between the Charite Medical Faculty and the Max Delbrueck Center, Berlin, Germany

 

The complex microstructure of the myocardium is pivotal for cardiac function and can provide important information about the underlying (bio)physical principles and (patho)physiological mechanisms. Probing human myocardial fiber structure in vivo has been described, but remains challenging due to cardiac and respiratory motion. Susceptibility based MRI provides excellent contrast which can be used to investigate tissue microstructure and track fibers in the brain. Recognizing this opportunity the work explores the applicability of susceptibility weighted MRI for probing human myocardial microstructure in vivo at 7.0 T.

                    1437.   Detection of Hepatic Glycogen by 1D ISIS Localized 13C MRS at 7T.

                                Martin Krssak1, 2, Martin Gajdosik2, Ladislav Valkovic2, Wolfgang Bogner2, Michael Krebs1, Anton Luger1, Siegfried Trattnig2, Marek Chmelik2

                                1Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, 1090, Austria; 2High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Wien, Austria

 

The aim of this study was to introduce and test the 13C MRS localization scheme suitable for the measurement of hepatic glycogen at 7T in short acquisition time. One dimensional slice selective version of recently introduced fully adiabatic extended ISIS sequence was proposed and tested on phantom and in vivo on healthy volunteers. 1D ISIS scheme applied at 7T presented optimal localization performance and sufficient signal to noise of natural abundance 1-13C hepatic glycogen doublet in relatively short acquisition times (4´16´´).

 

Traditional Poster

RF Design & Mapping

Traditional Poster Hall     Tuesday 10:00-12:00                                                                     

                    1438.   Joint Design of Continuous Excitation K-Space Trajectory and RF Pulse for 3D Tailored Excitation

                                Hao Sun1, Jeffrey A. Fessler1, Douglas C. Noll2, Jon-Fredrik Nielsen2

ISMRM_MagnaLogo.jpg                                 1Electrical Engineering and Computer Science, the University of Michigan, Ann Arbor, MI, United States; 2Biomedical Engineering, the University of Michigan, Ann Arbor, MI, United States

 

In 3D tailored RF pulse design, one typically predetermines a k-space (gradient) trajectory and then designs the corresponding RF waveforms for a target excitation pattern. Recently, the KT-points method was proposed as an approach for jointly designing the trajectory and RF pulses for 3D flip-angle homogenization (B1 shimming). KT-points models the 3D pulse design as a sparse approximation problem and selects sparse phase encoding locations by either a greedy approach or a simple inverse Fourier transform ignoring transmit coil sensitivity and field inhomogeneity. However, with only a few discrete phase encoding locations, it is difficult to approximate a non-smooth target excitation pattern in 3D. Also, it is relatively inefficient to traverse 3D k-space by discrete gradient blips with no RF transmission along those blips. In this work, we extend the KT-points method to a joint optimization of the continuous k-space trajectory and the RF waveform by: (1) applying local minimization to further optimize those KT points, and (2) efficiently ordering those points and generating a fast gradient waveform to traverse those points. We evaluate our proposed joint design with and without local minimization, and compare them with a recently proposed continuous nonselective spiral (SPINS) trajectory for 3D cubic excitation.

                    1439.   Multi-Slice Ultrafast Spatiotemporal Encoding (SPEN) MRI by New Two Dimensional Excitation Pulses

                                Rita Schmidt1, Lucio Frydman1

ISMRM_MagnaLogo.jpg                                 1Chemical Physics, Weizmann Institute of Science, Rehovot, Israel

 

Two-dimensional (2D) excitation pulses are often used for localization in spectroscopic imaging and for in-plane region-of-interest delineation in MRI.  Recent research has shown that these RF manipulations can also be based on spatiotemporal encoding (SPEN) principles.  SPEN is a spatiotemporal manipulation that has also been used for single-shot ultrafast MRI. Fast volumetric SPEN MRI acquisitions, however, are still challenged. The present work merges the benefits of both 2D SPEN-based excitation and 2D SPEN single-shot acquisitions, demonstrating a multi-slice ultrafast sequence. Experiments testing these ideas were demonstrated on phantom as well as on brain volunteer imaging experiments at 3 T.

 

 

                    1440.   Nonlinear-Phase Multiband 90°-180° RF Pair with Reduced Peak Power

                                Kangrong Zhu1, Adam B. Kerr1, John M. Pauly1

                                1Electrical Engineering, Stanford University, Stanford, CA, United States

 

Multiband RF pulses are central to the signal excitation in simultaneous multislice acquisitions. The peak amplitude has been a limiting factor in multiband RF design, especially in multiband spin-echo pulse design. In this work, nonlinear-phase multiband pulses, which have reduced peak power compared to linear-phase pulses, are designed. A pair of 90°-180° nonlinear-phase multiband pulses are applied to generate a linear-phase echo. An additional reference phase is applied to each individual excited band to further reduce the peak power of the multiband pulse.

                    1441.   A Robust and Low-Power Adiabatic T2 Preparation for Cardiovascular Imaging at High Magnetic Field

                                Ruud B. van Heeswijk1, 2, Kieran R. O'Brien, 23, Jean Delacoste1, 2, Matthias Stuber1, 2

                                1Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland; 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland; 3Radiology, University of Geneva, Geneva, Switzerland

 

An adiabatic T2 Preparation module (T2Prep) at high magnetic field normally requires too much energy to allow it to be combined with bSSFP imaging. Numerically optimized adiabatic pulses were therefore used to design a T2Prep for cardiovascular imaging at high magnetic field. The energy efficiency of this optimized T2Prep was established at 3T and compared to standard adiabatic T2Prep. Finally, T2-prepared bSSFP cardiovascular imaging and coronary MRA were demonstrated in healthy volunteers.

                    1442.   MultiPINS: PINS + MultiBand Hybrid RF Pulse with Reduced SAR for SMS Imaging at Ultra High Field Strength

                                Cornelius Eichner1, 2, Robert Turner, Lawrence L. Wald1, Kawin Setsompop1

                                1Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; 2 Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Saxony, Germany

 

Simultaneous Multi Slice (SMS) acquisition enables increased temporal resolution and acquisition speed. However, at ultra high field strengths, SAR constraints of SMS RF pulses can enforce slower acquisition speed. We propose a novel MultiPINS RF pulse design that combines PINS and MultiBand pulses to achieve lower SAR. Slice profiles and off-resonance behavior of this pulse were evaluated using Bloch simulations. The MultiPINS pulse achieves similar slice profiles, but significantly reduced energy transmission and peak RF voltage. In-vivo high-resolution Blipped-CAIPI SMS diffusion MRI data with 3x multiband acceleration were acquired at 7T to show the usefulness of this new pulse design.

 

 

                    1443.   Multi-Dimensional Susceptibility Conditioned RF Pulse (SCOPE) Design: A Spokes Approach

                                Wei Feng1, Yang Xuan2, E Mark Haacke

                                1Radiology, Wayne State University, Detroit, MI, United States; 2Radiology, Wayne State University, MI, United States

 

A novel multi-dimensional spokes RF pulse design method is proposed to compensate for bulk susceptibility-induced phase variations. Under the small flip angle regime, there is a Fourier relationship between the excitation pattern and the RF and gradient waveforms, which traverses the excitation k-space. The conventional spokes pulse design approach is modified such that the cost function incorporates both magnitude and phase constraints inside the desired region of interest (ROI) based on susceptibility field map, while the phase is allowed to vary arbitrarily outside the ROI. Numerical Bloch simulations and imaging experiments were performed for 1D, 2D and 3D pulse design applications. It is shown that the proposed method is viable and could have significant potential in susceptibility-related imaging applications.

                    1444.   Design of a Variable-Rate Selective Dual-Band FOCI Pulse for Spin Labeling

                                Fabian Zimmer1, Frank G. Zöllner1, Lothar R. Schad1

                                1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany

 

For pulsed arterial spin labeling (ASL) the quality of the slice-selective inversion is decisive because of the inherent low perfusion contrast. Commonly, adiabatic inversion pulses are used. However, the adiabatic condition has to be fulfilled, leading to a compromise between the maximum available coil voltage and profile quality, i.e. pulse parameters. Especially the high RF power demand of adiabatic dual-band inversion pulses normally leads to inversion profiles that are unusable for ASL. We present a dual-band FOCI inversion pulse with reduced RF power requirements that conserves the high quality of a single-band FOCI pulse.

                    1445.   Implementation of a Self-Refocused Adiabatic Spin Echo Pulse-Pair Modulated Using the Power Independent of the Number of Slices (PINS) Technique for Simultaneous B1-Insensitive Multi-Slice Imaging

                                Rebecca Emily Feldman1, Haisam Islam2, Priti Balchandani1

                                1Translational and Molecular Imaging Institute, Icah School of Medicine at Mount Sinai, New York, United States; 2Bioengineering, Stanford University, CA, United States

 

High field MR can be challenging due to limited slice coverage, B1-inhomogeneity. Adiabatic pulses can limit sensitivity to B1-inhomogeneity, however adiabatic pulses deposit quadratic phase that is difficult to refocus and are SAR intensive. Similarly, simultaneous multi-slice imaging can accelerate image acquisition at high fields but RF pulses created as the superposition of multiple slice RF pulses can rapidly exceed safe SAR limits. Using  a 'Power Independent of Number of Slices' (PINS) technique, multiple slices can be excited simultaneously at lower power. We implemented a adiabatic PINS refocusing pulse with a matched phased PINS excitation pulse.

                    1446.   A General Numerical VERSE RF Pulse Design Framework

                                Nii Okai Addy1, Dwight G. Nishimura1

                                1Electrical Engineering, Stanford University, Stanford, CA, United States

 

A recent method for a flexible, numerical spiral imaging trajectory design can be adapted to RF pulse design. With this general framework, various VERSE RF pulses can be designed in one or multiple dimensions. This work presents results for slab-selection and spiral excitation.

                    1447.   Variable-Rate Design of Quieter Slice-Select Pulses

                                Christopher J. Hardy1, Seung-Kyun Lee1, Michael J. Wittbrodt1

                                1GE Global Research, Niskayuna, NY, United States

 

Slice-select pulses can be made quieter by derating them, i.e. by reducing gradient slew rate and/or amplitude (along with RF bandwidth), but this increases minimum echo time. The variable-rate principle is used here to design slice–select pulses with improved acoustic signature and with identical slice profiles on-resonance, without lengthening pulse duration.

 

                    1448.   RF Pulse Design for Low SAR Simultaneous Multislice (SMS) Excitation Using Optimal Control

                                Christoph Stefan Aigner1, Christian Clason2, Armin Rund2, Rudolf Stollberger1

                                1Institute of Medical Engineering, Graz University of Technology, Graz, Austria; 2Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria

 

Optimal control (OC) is a flexible framework for the design of RF pulses with arbitrary slice profiles, even in the presence of relaxation effects and field inhomogeneities, and is therefore well suited for simultaneous multislice (SMS) imaging. We demonstrate the ability of this approach to generate RF pulses with arbitrary (large) flip angles, slice thickness, slice gaps and slice numbers. The results for two and three slices of 4mm thickness are validated on a 3T MR scanner and indicate the applicability of the proposed method.

                    1449.   RF Pulse Design Using Linear and Nonlinear Gradient Fields: A Multi-Dimensional K-Space Approach

                                Emre Kopanoglu1, Leo K. Tam1, Robert Todd Constable1

                                1Dept. Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, United States

 

The effect of using nonlinear gradient fields (NLGFs) on excitation fidelity is studied, specifically on a multi-dimensionally selective excitation scheme. For this purpose, three nonlinear and two linear gradient fields (LGFs) are used. Two-dimensionally selective RF pulses are designed utilizing more than two fields simultaneously, using a multi-dimensional k-space approach. Using simulations, it is shown that increasing the number of k-space dimensions beyond the number of spatial coordinates may yield excitation profiles with lower error, compared to the target profile. It is also shown that, NLGFs may improve excitation fidelity, even for profiles that are more compatible with LGFs.

                    1450.   Homogeneous Neuroimaging at 7 Tesla with Short Tailored Radiofrequency Pulses Using High Permittivity Dielectric Bags

                                Joep Wezel1, Maarten Versluis1, Andrew Webb1, Matthias van Osch1, Peter Börnert, 12

                                1C.J. Gorter center for high field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands; 2Philips Research Europe, Hamburg, Germany

 

Neuroimaging at 7 tesla is complicated by the high degree of B1-inhomogeneity within the brain. Spezialized RF pulses that take the  B1 distribution into account can compensate for the inhomogeneous field. These pulses are generally longer than the regular pulses, leading to increased sensitivity to B0 deviations. To counter this trend we apply high permittivity dielectric pads that reduce the severity of the flip angle voids. This potentially leads to the design of shorter RF pulses to compensate for the remainder of the inhomogeneities. We have simulated three pulse lengths with and without the bags and verified this in-vivo.

                    1451.   Variable Density 2D Spiral Excitation with Self Compressed Sensing

                                Wenwen Jiang1, 2, Michael Lustig3, John Pauly4, Peder E.Z. Larson5

                                1Graduate Group in Bioengineering, University of California, Berkeley, Berkeley, CA, United States; 2University of California, San Francisco, San Francisco, CA, United States; 3Electrical Enigneering and Computer Science, University of California, Berkeley, CA, United States; 4Electrical Enigneering, Stanford University, CA, United States; 5Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States

 

2D spiral excitation pulses are potentially valuable for bolus tracking and reduced FOV imaging. But 2D excitation pulses are usually long, given the FOV and resolution requirements, which results in off-resonance blurring of the spatial profile. Subsampled spiral trajectories could shorten the duration of the pulse but resulting in aliasing sidelobes in the excitation profile. In analogy to the subsampled data acquisition, subsampled excitation profiles can be designed to produce incoherent sidelobes. These can be further reduced by the fact that spin-echoes square the linear excitation dramatically shrinking the sidelobes. With the design of appropriate variable density spiral trajectories, this method will effectively suppress aliasing sidelobes while resulting in shorter excitation pulses.

                    1452.   Optimization of Fast K-Space Trajectories for 3D Spatially Selective Parallel Excitations

                                Mathias Davids1, 2, Bastien Guérin2, Lothar R. Schad1, Lawrence L. Wald2, 3

ISMRM_MagnaLogo.jpg                                 1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, BW, Germany; 2Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; 3Harvard-MIT, Division of Health Sciences and Technology, Cambridge, MA, United States

 

The k-space trajectory, in addition to the RF, possesses powerful degrees of freedom to enhance 3D parallel selective excitations. A novel approach on rapidly designing arbitrarily shaped time-optimal trajectories was used to simultaneously optimize the trajectory and RF pulse. The trajectory was defined by shape parameters that were optimized for a cubic ROI and brain only excitation. Two trajectories were optimized – a 3D Cross and a 3D Concentric Shells trajectory – with durations of less than 7 ms each. The excitation RMSE could be reduced by up to 60% in an eight channel 7T setup, yielding applicable 3D selective excitation pulses.

                    1453.   On Variant Strategies to Solve the Magnitude Least Squares Optimization Problem in Parallel Transmission RF Pulse Design and Under Strict SAR and Power Constraints

                                Nicolas Boulant1, Andres Hoyos-Idrobo1, Pierre Weiss2, Aurelien Massire1, Alexis Amadon1

                                1Neurospin, CEA, Saclay, Ile de France, France; 2ITAV, CNRS, Toulouse, Midi-Pyrénées, France

 

Despite the importance of the magnitude least squares problem in parallel transmission pulse design and the availability of other powerful numerical optimization methods, this problem has been faced almost exclusively with the so-called variable exchange method. Here, we investigate various two stage strategies and incorporate directly the SAR and power constraints. Different schemes such as sequential quadratic programming, interior point methods, semi-definite relaxation and magnitude squared least squares relaxations are studied in the small and large flip angle regimes with B1 and DB0 maps obtained in-vivo on a human brain at 7 Tesla.

                    1454.   Local and Global SAR Constrained Large Tip Angle 3D Kt Points Parallel Transmit Pulse Design at 7 T

                                Filiz Yetisir1, Bastien Guerin2, Lawrence L. Wald2, 3, Elfar Adalsteinsson1, 3

                                1Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States; 2Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; 3Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, United States

 

Explicit SAR constraints have been proven useful for slice selective small tip angle pulse design. We propose a nonselective pulse design method that explicitly constrains local SAR and RF peak amplitude at large tip angle and demonstrate that when local SAR is controlled directly rather than via control of peak RF voltage, safer pulses with better excitation profiles are obtained. Our method is more practical than Tikhonov regularized strategies since it only requires one run to ensure that all the limits (SAR and RF) are satisfied.

                    1455.   3DREAM – a Three-Dimensional Variant of the DREAM Sequence

                                Daniel Brenner1, Desmond H. Y. Tse2, Eberhard D. Pracht1, Thorsten Feiweier3, Rüdiger Stirnberg1, Tony Stöcker1

                                1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; 2INM-4, Research Centre Jülich GmbH, Jülich, Germany; 3Siemens AG, Healthcare Sector, Erlangen, Germany

 

A 3D variant of the DREAM sequence, with a spiral phase encode view ordering, is utilized for B1 mapping at 7T. Together with short non-selective preparation and imaging RF pulses this enables whole volume B1 mapping of the human head in 15s or even a single shot - which only lasts 3s – at negligible SAR levels (1%). Good agreement is found with a reference AFI dataset with degraded quality in a low tip angle regime due to the low SNR of the STE* image.

                    1456.   Optimization of Amplitude-Modulated Pulses for Bloch-Siegert Based B1 Mapping

                                Qi Duan1, Peter van Gelderen1, Souheil J. Inati2, Jeff H. Duyn1

                                1AMRI, LFMI, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States; 2FMRIF, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States

 

This abstract investigates fast simultaneous B0/B1+ mapping by Bloch-Siegert shift via lowering the off-resonance frequency of this pulse, as theoretical analysis indicated that the sensitivity of Bloch-Siegert based B1+ mapping can be substantially improved when irradiating closer to resonance. Using optimized irradiation pulse shape and gradient crushers to minimize direct excitation effects, in vivo experiments on human brain at 7T confirmed the improved sensitivity available with this approach operating with peak B1+ much larger than the frequency offset. This improved sensitivity translated into an 80% reduction in B1+ estimation errors, without increasing tissue heating.

                    1457.   Toward B1 Estimation Using Coil Locators

                                Parnian Zarghamravanbakhsh1, Christopher Ellenor1, John M. Pauly1, Greig Scott1

                                1Electrical engineering, Stanford university, Stanford, CA, United States

 

We propose a method to predict B1 filed using coil geometry and  location in imaging coordinate system without doing B1 mapping. Most of B1 mapping are done without any assumption about the coil geometry and location. Coils location are found by placing markers on coil conductors, then by acquiring three sets of 1D projections to localize the markers ,coil plane can be detected. Having known the coil location and geometry, B1 field distribution can be obtained by computational analysis .To validate the method, we compare simulated  with measured results. Field prediction can be used in auto-calibration and RF pulse design.

 

                    1458.   Lowering the B1 Threshold for BEAR B1 Mapping

                                Kalina V. Jordanova1, Dwight G. Nishimura1, Adam B. Kerr1

                                1Electrical Engineering, Stanford University, Stanford, CA, United States

 

We redesign the BEAR B1 mapping method to use HSn pulses, which have lower adiabatic thresholds. By optimizing the HSn pulse parameters, we can reliably acquire B1 maps for lower nominal peak B1 than with the original BEAR method. We validate the performance of BEAR with HSn pulses via simulation and in vivo at 3T, with average errors from the original BEAR method of less than 3%. This method will be useful for reliably acquiring B1 maps for lower B1 values.

                    1459.   Decoupled RF-Pulse Phase Sensitive B1 Mapping

                                Daniel J. Park1, Neal K. Bangerter1, 2, Glen R. Morrell2

                                1Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States; 2Department of Radiology, University of Utah, SLC, UT, United States

 

B1 mapping mapping is an important component of quantitative MRI and parallel transmission.  Although many B1 mapping methods have been introduced and analyzed, there is no clear superior method.  One method, the Bloch-Siegert shift method, has potential for improved B1 mapping of parallel transmit arrays through separation of excitation and the B1 encoding pulse.  We introduce a modification to the Phase Sensitive (PS) method that allows similar improvement by decoupling the compound excitation pulse in the PS method.  We introduce a brief Monte Carlo based statistical analysis (mean bias and standard deviation) which illustrates the potential of this method.

                    1460.   Reduced-FOV Lumbar Spine T MR Imaging Using High-Low EP-2DRF Excitation Pulse

                                Qinwei Zhang1, Yi-Xiang J. Wang1, Heather Ting Ma2, Queenie Chan3, Jing Yuan1, 4

                                1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong; 2Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong, China; 3Philips Healthcare, Hong Kong, Hong Kong; 4CUHK Shenzhen Research Institute, Shenzhen, Guangdong, China

 

T1ρ imaging has been proved to be a sensitive biomarker for disc degeneration while suffering from long scan time. Large field of view and respiratory motion further adversely affect the mapping results.  We proposed a 2DRF pulse with novel high-low EP excitation trajectory to realize reduced field of view (rFOV) T1ρ imaging in lumbar spine region on a 3T clinical scanner. The scan time was halved and motion artifact was eliminated. Good consistency between rFOV and full FOV T1ρ maps  was observed. The proposed 2DRF has potential to be used for high-resolution spine T1ρ imaging in routine clinical scan.

                    1461.   Correction of 2D RF Pulses

                                Yuval Zur1

                                1GE Healthcare, Tirat Carmel, Israel

 

Two dimensional (2D) RF pulses with EPI excitation trajectory are extremely sensitive to system imperfections such as eddy currents and waveform distortions. These imperfections cause stop band excitation and pass band saturation. A method to correct these 2D RF pulses is presented. The correction is done by adding a phase to even sub pulses and gradient blips to the oscillatory excitation gradient. The added phase and the area of the blips are determined by a calibration done at system installation. The method was applied successfully to spectral spatial RF pulses at oblique and non oblique slice orientations.

                    1462.   Characterizing the Inherent and Noise-Ind