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| 2568 | Computer 41
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7T spin-echo dynamic susceptibility contrast MRI to assess cerebral microvascular perfusion |
| Elles P. Elschot1,2, Marieke van den Kerkhof1,2, Robert J. van Oostenbrugge2,3,4, Abraham A. Kroon4,5, Walter H. Backes1,2,4, and Jacobus F. A. Jansen1,2,6 | ||
1Radiology & Nuclear Medicine, Maastricht University Medical Center +, Maastricht, Netherlands, 2School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands, 3Neurology, Maastricht University Medical Center +, Maastricht, Netherlands, 4School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands, 5Internal Medicine, Maastricht University Medical Center +, Maastricht, Netherlands, 6Electrical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands |
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Keywords: Contrast Mechanisms, Perfusion Ultra-high-field exploits the possibilities of MRI techniques, which are less sensitive at lower field strength, such as spin-echo (SE) perfusion MRI. We assessed the feasibility of SE dynamic susceptibility contrast MRI at 7T and investigated the ability to measure variations in perfusion in an elderly, partially hypertensive, population (n=36). Microvascular cerebral blood flow (CBF) was higher in grey matter compared to white matter, corresponding with biological expectations, serving as a first validation step. Furthermore, CBF significantly decreased with age. |
| 2569 | Computer 42
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Effect of general anesthesia on cerebral blood flow measured by Arterial Spin Labeling: A retrospective study |
| Thomas Lindner1, Monika Huhndorf2, Christine Eimer3, Tobias Becher3, Hajrullah Ahmeti4, Olav Jansen2, Michael Synowtiz4, Michael Helle5, and Stephan Ulmer2,6 | ||
1UKE Hamburg, Hamburg, Germany, 2Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel, Germany, 3Department of Anesthesia, University Hospital Schleswig-Holstein, Kiel, Germany, 4Department of Neurosurgery, University Hospital Schleswig-Holstein, Kiel, Germany, 5Philips Gmbh Innovative Technologies, Hamburg, Germany, 6neurorad.ch, Zurich, Switzerland |
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Keywords: Arterial spin labelling, Brain, Anesthesia In this study, we non-invasively evaluated the change in cerebral blood flow (CBF) and correlation with mean arterial pressure (MAP) before and during anesthesia using Arterial Spin Labeling. It could be shown that both CBF and MAP are reduced comparing the awake and anesthesia-induced state in patients. |
| 2570 | Computer 43
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Age dependent changes of water exchange rate across the blood-brain barrier (BBB) in 115 subjects with age ranging from 8 to 87 years |
| Xingfeng Shao1, Qinyang Shou1, Kimberly Felix2, Brandon Ojogho1, Xuejuan Jiang2,3, Brian T. Gold4, Megan M. Herting2, and Danny JJ Wang1 | ||
1Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 2Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 3Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 4Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, KY, United States |
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Keywords: Arterial spin labelling, Permeability, BBB water exchange, permeability, ageing We studied age-related BBB water exchange rate (kw) changes in a wide range of age groups with 115 subjects using diffusion prepared pseudo-continuous arterial spin labeling (DP-pCASL). We observed a significant trend of decreasing kw with age (slow when ≤50 years old and fast when >50 years old) and large spread of kw values in subjects >50 years, which may indicate compromised BBB function in some ageing populations. The inverted U-shaped correlations between kw versus age suggest a more complex age dependent changes in hippocampus and PHG regions. |
| 2571 | Computer 44
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Comparing the Repeatability of Cerebrovascular Reserve Measured by PET and ASL using Simultaneous PET/MRI |
| Moss Y Zhao1, Audrey P Fan2, Mohammad Mehdi Khalighi1, Dawn Holley1, Kim Halbert1, Maria Jovin1, Bin Shen1, Guido A Davidzon1, Elizabeth Tong1, Michael Moseley1, and Greg Zaharchuk1 | ||
1Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Biomedical Engineering, University of California Davis, Davis, CA, United States |
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Keywords: Arterial spin labelling, Perfusion Cerebrovascular reserve (CVR) is an important biomarker to assess vascular hemodynamics and link to the risk for acute strokes. Whilst several imaging modalities have been applied to measure CVR, their reproducibility remains to be elucidated. Here we compare the reproducibility of CVR measurements in 22 normal subjects between single and multi-delay ASL using 15O-water PET as the reference. Results implied that multi-delay ASL achieved a higher reproducibility and should be the preferred non-invasive modality for clinical applications. |
| 2572 | Computer 45
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Change in Blood-brain Barrier Permeability with Age – Comparing a Physiologically Informed Biophysical Model with a Triexponential Decay Model |
| Amnah Mahroo1 and Matthias Günther1,2,3 | ||
1Imaging Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany, 2MR-Imaging and Spectroscopy, University of Bremen, Bremen, Germany, 3mediri GmbH, Heidelberg, Germany |
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Keywords: Arterial spin labelling, Brain, Blood-brain barrier Permeability, Aging, Multi-TE ASL With age the integrity of blood-brain barrier (BBB) slowly deteriorates. Multi-TE ASL, being a water-based MRI method, offers detection of subtle changes in the BBB by probing T2 relaxation. In this study, we evaluated the sensitivity of multi-TE ASL method in detecting changes in the BBB occurring due to age using two models; a physiologically informed biophysical (PIB) model by estimating exchange time and a simpler tri-exponential decay (TD) model by determining the rate of change of tissue fraction. We found that both models were able to detect age-based changes in BBB. Moreover, PIB model showed higher robustness. |
| 2573 | Computer 46
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Assessment of Splenic Switch-Off With Arterial Spin Labeling in Adenosine Perfusion Cardiac MRI |
| Verónica Aramendia-Vidaurreta1,2, Sergio M. Solís-Barquero1,2, Ana Ezponda1,2, Marta Vidorreta3, Rebeca Echeverria-Chasco1,2, Marina Pascual4, Gorka Bastarrika1,2, and María A. Fernández-Seara1,2 | ||
1Radiology, Clínica Universidad de Navarra, Pamplona, Spain, 2IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain, 3Siemens Healthineers, Madrid, Spain, 4Cardiology, Clínica Universidad de Navarra, Pamplona, Spain |
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Keywords: Arterial spin labelling, Perfusion Splenic switch-off, defined as the stress to rest splenic blood flow (SBF) attenuation in response to adenosine, is an indicator of stress adequacy. This study aims to explore the ability of pseudo-continuous arterial spin labeling (PCASL) to identify splenic switch-off in patients with suspected CAD. In healthy subjects, multi-delay PCASL data were acquired to quantify SBF and determine the adequate postlabeling delay. In patients, single-delay PCASL and first-pass perfusion images were acquired under rest and adenosine conditions. This study could demonstrate the feasibility of PCASL to identify splenic switch-off during adenosine perfusion MRI. |
| 2574 | Computer 47
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Optimal PLD selection for White Matter perfusion measurements at 7T. |
| Emiel C.A. Roefs1, Lydiane Hirschler1, Natalia Petridou2, and Matthias J.P. van Osch1 | ||
1Radiology, C.J. Gorter MRI Center, Leiden Univeristy Medical Center, Leiden, Netherlands, 2Radiology, Center for Image Sciences, Univeristy Medical Center Utrecht, Utrecht, Netherlands |
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Keywords: Arterial spin labelling, High-Field MRI White matter (WM) perfusion measurements are challenging because of the generally lower perfusion in combination with a longer bolus arrival time (BAT). We investigated the use of long-PLD perfusion measurements at high-field (7T) to compensate for longer BAT in WM. We showed that 3D background suppressed FAIR at 7T with a PLD of 2300ms provides robust perfusion measurement in almost 80% of deep WM within 4min of scan time. |
| 2575 | Computer 48
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APOE genotype-dependent sex differences in cortical hemodynamics measured with arterial spin labeling MRI |
| Nikou Louise Damestani1,2, John Jacoby1, Barnaly Rashid1,3, Allison E Lovely1, Shrikanth M Yadav1, Aurea Michael1, Marziye Eshghi4, Melissa Terpstra5, Carlos Cruchaga6,7,8, David H Salat1,2,9, and Meher R Juttukonda1,2 | ||
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Department of Neurology, Harvard Medical School, Boston, MA, United States, 4MGH Institute of Health Professions, Boston, MA, United States, 5MU School of Medicine, University of Missouri, Columbia, MO, United States, 6Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States, 7NeuroGenomics and Informatics Center, Washington University School of Medicine, St. Louis, MO, United States, 8Hope Center for Neurologic Diseases, Washington University, St. Louis, MO, United States, 9Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, MA, United States |
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Keywords: Arterial spin labelling, Aging Identifying biomarkers that could characterize typical from atypical aging is crucial for understanding the aging process. One of the most significant genetic risk factors for Alzheimer’s Disease, an age-related neurodegenerative disorder, is the presence of an apolipoprotein-E (APOE) ε4 allele. Here, we investigate the impact of APOE genotype on cortical hemodynamics in a large cohort of participants across the lifespan, accounting for interacting effects of age, sex, and cardiovascular risk. We found unique spatial patterns of cerebral blood flow and arterial transit time between males and females within distinct APOE genotypes, potentially indicating the presence of a complex interaction. |
| 2576 | Computer 49
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The ASL Challenge Reproduction Study: Replicating Findings from The OSIPI-ISMRM ASL MRI Challenge |
| Channelle Tham1, Ahmed Abdalle2, Joseph G Woods3, Maria-Eleni Dounavi4, Andre Pascoal5, and Udunna Anazodo6 | ||
1Department of Cognitive Neuroscience, Radboud University, Nijmegen, Netherlands, 2Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, 3Wellcome Centre for Integrated Neuroimaging, FMRIB, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, United Kingdom, 4Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, 5Instituto de Radiologia e Departamento de Radiologia e Oncologia, University of Sao Paulo, Sao Paulo, Brazil, 6Montreal Neurological Institute, McGill University, Montreal, QC, Canada |
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Keywords: Arterial spin labelling, Challenges, Reproducibility While the recommendation for ASL acquisition is widely adopted to standardize quantification of cerebral blood flow (CBF), ASL analysis still produces wide variability in CBF estimates. The recent OSIPI-ISMRM ASL MRI Challenge highlighted how differences in image processing contribute to CBF variability. Here, we explored the replicability of ASL image processing approaches when used as documented to quantify CBF. The results of 5 of the 8 ASL Challenge teams were replicated and compared to their submitted results. The overall errors in global mean CBF were 0.03-5 times larger in the replicated results, demonstrating the need for ASL analysis standards. |
| 2577 | Computer 50
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Extracting CBF and ATT from One or Two Post-labeling Delays-based Arterial Spin Labeled Perfusion MRI via Deep Learning |
| Yiran Li1, Xiufeng Li2, John A Detre3, and Ze Wang1 | ||
1University of Maryland School of Medicine, Baltimore, MD, United States, 2University of Minnesota, Minneapolis, MN, United States, 3University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling Cerebral blood flow (CBF) and arterial transit time (ATT) can be quantified through fitting the arterial spin labeling (ASL) perfusion MRI signal acquired at different post-labeling delays (PLDs) into a kinetic model. Acquiring multiple-PLD ASL MRI needs exponentially prolonged total scan time compared to the single-PLD acquisition, making it highly sensitive to motions and impractical for clinical use. We proposed a deep neural network that can reliably estimate ATT and CBF maps from significantly fewer PLD ASL MRI acquisitions without image quality loss. |
| 2578 | Computer 51
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DSC-MRI and ASL-MRI Measured Perfusion in Glioblastoma: Are they Competitive or Complementary? |
| Limin Zhou1, Yiming Wang2, Marco C. Pinho1,3, Durga Udayakumar1,3, Michael Youssef4,5, Joseph A. Maldjian1,3, and Ananth J. Madhuranthakam1,3 | ||
1Department of Radiology, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 2Philips Healthcare, Shanghai, China, 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 4Department of Neurology, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 5Department of Hematology and Oncology, University of Texas Southwestern Medical Center, DALLAS, TX, United States |
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Keywords: Arterial spin labelling, Perfusion, Dynamic susceptibility contrast (DSC), Brain, Cancer, Glioblastoma (GBM) |
| 2579 | Computer 52
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Investigating border zone hemodynamics with time-encoded super-selective pCASL in internal carotid and basilar artery perfusion territories |
| Lena Vaclavu1 and Matthias JP van Osch1 | ||
1C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands |
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Keywords: Arterial spin labelling, Perfusion, super-selective, time-encoded, borderzones The borders between cerebral perfusion territories are regions of the brain that are susceptible to infarction. In this study, time-encoded super-selective pCASL was implemented to study the hemodynamic properties of the border zones between the left internal carotid artery and basilar artery perfusion territories. Perfusion territories were well-defined with little-to-no detectable overlap. The longest arrival times were found at the border zones, compared to 'inland' of the perfusion region. Combining time-encoded with super-selective pCASL enables the simultaneous investigation of border zones and their arrival times. |
| 2580 | Computer 53
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Impact of age and sex on regional white matter hemodynamics across the adult lifespan |
| Nikou Louise Damestani1,2, John Jacoby1, Qiyuan Tian1,2, Allison E Lovely1, Shrikanth M Yadav1, David H Salat1,2,3, and Meher R Juttukonda1,2 | ||
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, MA, United States |
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Keywords: Arterial spin labelling, Aging White matter perfusion has been difficult to measure with arterial spin labeling (ASL) MRI due to the elongated arterial transit times of white matter. Here, we identified changes in white matter cortical hemodynamics associated with age and between sex for the first time using multi-delay pseudo-continuous ASL with tract-based analyses in a large typically aging cohort. We found reductions in white matter CBF and increases in white matter ATT with advancing age, as well as widespread sex differences across tracts. This work serves as the first step towards understanding the relationship between white matter physiology and age-related structural decline. |
| 2581 | Computer 54
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Detectability of changes in the blood-brain barrier permeability to water using optimised multi-TE pseudo-continuous arterial spin labelling |
| Logan X. Zhang1,2 and Michael Chappell1,3 | ||
1Sir Peter Mansfield Imaging Centre and Mental Health & Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, United Kingdom, 2Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom, 3Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom |
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Keywords: Arterial spin labelling, Arterial spin labelling The blood-brain barrier integrity can be reflected by the pre-exchange lifetime of water molecules, Tex, which can be measured using multi-TE multi-delay ASL. Nevertheless, the low SNR of ASL limits the detectability of subtle Tex changes within a feasible scan time for clinical applications. In this study, optimised protocols were evaluated for the theoretical detectability of 10% changes in haemodynamic parameters. Simulation shows that while changes in CBF and arterial transit time (ATT) could be detected on individual level in a five-minute scan, the same detectability of Tex would require a minimum of 6 subjects within ten minutes of scanning. |
| 2582 | Computer 55
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Increased Blood-brain Barrier Permeability in Response to Caffeine Challenge |
| Amnah Mahroo1, Simon Konstandin1,2, Daniel Christopher Hoinkiss1, Jochen Hirsch1, and Matthias Günther1,2,3 | ||
1Imaging Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany, 2mediri GmbH, Heidelberg, Germany, 3MR-Imaging and Spectroscopy, University of Bremen, Bremen, Germany |
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Keywords: Arterial spin labelling, Brain, Blood-brain Barrier (BBB) Permeability, caffeine, multi-TE ASL Caffeine is a commonly used stimulant drug and is known to change brain physiology by constricting vessels leading to decreased perfusion. We tested the impact of caffeine ingestion on blood-brain barrier (BBB) permeability by measuring exchange time using multi-TE ASL technique. Six healthy volunteers were examined for five pre-caffeine sets and six post-caffeine sets. The multi-TE two-compartment model was used to estimate exchange time (Tex) along with perfusion and ATT. We found that perfusion and Tex decreased over time while ATT increased. Decreased Tex indicates that the labelled water transferred at a faster rate reflecting increased BBB permeability. |
| 2583 | Computer 56
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The value of ASL combined with DTI for detection of impaired renal allograft function |
| Bin Jiang1, Yangyang Tian2, Ximing Wang1, Peng Wu3, Jiayi Wan1, Mengjiao Yin1, Ning Wang1, Rui Xu1, Linkun Hu2, and Mo Zhu1 | ||
1Department of Radiology, The First Affiliated Hospital of Soochow University, Suzhou, China, 2Department of Urology, The First Affiliated Hospital of Soochow University, Suzhou, China, 3Philips Healthcare, Shanghai, China |
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Keywords: Arterial spin labelling, Kidney Allograft injury continues to be a major problem in renal allograft recipients, which leads to eventual graft loss. Non-invasive and reliable detection of impaired renal allograft function is crucial to preventing irreversible nephron loss and graft failure. This study aims to investigate the value of ASL combined with DTI for the detection of impaired renal allograft function. Results showed that a higher diagnostic efficacy could be achieved through the combined use of ASL and DTI. |
| 2584 | Computer 57
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Evaluation of 3D Stack-of-Spiral Turbo FLASH Acquisitions for PCASL- and VSASL-Derived Brain Perfusion Mapping |
| Dan Zhu1,2, Feng Xu1,2, Dapeng Liu1,2, Doris Lin2, Peter van Zijl1,2, and Qin Qin1,2 | ||
1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 2The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling The most-used 3D acquisition for ASL at 3T is GRASE or stack-of-spiral (SOS) based FSE, which requires multiple shots to cover the full k-space. Alternatively, turbo FLASH (TFL) acquisition allows longer echo trains with slower T1 (than T2) relaxation, and 3D SOS-TFL has the potential to reduce the number of shots to even single-shot, thus improving the temporal resolution for ASL. Here we demonstrated comparable performance of 3D SOS-TFL with 3D GRASE on PCASL- and VSASL-derived CBF mapping and VSASL-derived CBV mapping at 3T on 12 healthy subjects, and the utility of 3D SOS-TFL on a stroke patient. |
| 2585 | Computer 58
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Reproducibility of Pseudocontinuous Arterial Spin Labeling Measured Perfusion in Healthy Volunteers and Glioblastoma Patients |
| Limin Zhou1, Yiming Wang2, Marco C. Pinho1,3, Durga Udayakumar1,3, Michael Youssef4,5, Joseph A. Maldjian1,3, and Ananth J. Madhuranthakam1,3 | ||
1Department of Radiology, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 2Philips Healthcare, Shanghai, China, 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 4Department of Neurology, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 5Department of Hematology and Oncology, University of Texas Southwestern Medical Center, DALLAS, TX, United States |
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Keywords: Arterial spin labelling, Precision & Accuracy, Reproducibility, Precision Accuracy, Perfusion, Cancer, Glioblastoma (GBM), Translational studies We evaluated the intra-session repeatability and inter-session reproducibility of brain and tumor perfusion measured using 3D pseudo-continuous Arterial spin labeled (PCASL) MRI with TSE based Cartesian acquisition with spiral profile reordering (CASPR) in comparison to 3D pCASL with GRASE in healthy volunteers and glioblastoma (GBM) patients at 3T. 3D pCASL with TSE-CASPR or GRASE provided high intra-session repeatability and 3 weeks inter-session reproducibility in both volunteers and GBM patients. While both readouts generated robust images, TSE-CASPR provided images with reduced distortion particularly in GBM patients and could be a better readout for pCASL measured perfusion in GBM patients. |
| 2586 | Computer 59
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Microvascular specificity in velocity-selective arterial spin labeling: Effects of the post-labeling delay |
| Ryan A. Barnes1,2, Conan Chen1,2,3, Eric C. Wong1,3,4, Thomas T. Liu1,3,4,5, and Divya S. Bolar1,3 | ||
1Center for fMRI, University of California San Diego, La Jolla, CA, United States, 2Department of Electrical and Computer Engineering, UC San Diego, La Jolla, CA, United States, 3Department of Radiology, UC San Diego, La Jolla, CA, United States, 4Department of Psychiatry, UC San Diego, La Jolla, CA, United States, 5Department of Bioengineering, UC San Diego, La Jolla, CA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling, Velocity-selective ASL, CBF Velocity-selective ASL labels arterial blood spins close to the microvasculature if a sufficiently low velocity cutoff (Vcut) is used. Lowering Vcut, however, introduces diffusion and eddy current effects that confound the CBF measurement. A Vcut of 2 cm/s is typical to minimize these effects, but labels blood slightly upstream from the microvasculature; in this scenario, a non-zero post-labeling delay (PLD) allows time for additional microvascular delivery. We evaluate microvascular specificity (using the spatial coefficient of variation of CBF) as a function of PLD. We find that macrovascular specificity increases with PLD up to around 500ms for a typical ASL resolution. |
| 2587 | Computer 60
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Resting state neurovascular coupling patterns estimated using advanced multiband multi-echo BOLD/ASL imaging |
| Alexander D. Cohen1 and Yang Wang1 | ||
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States |
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Keywords: Arterial spin labelling, Data Analysis, Coupling, Simultaneous BOLD/ASL Impaired neurovascular coupling (NVC) plays a critical role in many neurovascular pathological processes. Several resting state fMRI methods have been used to estimate NVC including BOLD/CBF coupling and, to a lesser extent, ALFF and fALFF. In this study, resting state BOLD/CBF coupling was evaluated using advanced multiband multi-echo BOLD/ASL sequence and correlated with ALFF and fALFF in healthy volunteers. Significant correlation between BOLD/CBF coupling and ALFF and fALFF was seen in major brain network hubs. These results indicate MBME BOLD/ASL may provide similar, but complimentary measures of NVC compared to traditional RS metrics. |
| 2744 | Computer 41
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Efficient 3D cone trajectory design for improved combined angiographic, structural and perfusion imaging using arterial spin labelling |
| Qijia Shen1, Mark Chiew1,2,3, Wenchuan Wu1, and Thomas Okell1 | ||
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 3Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Keywords: Arterial spin labelling, Arterial spin labelling 4D combined angiographic, structural and perfusion radial imaging using arterial spin labelling (CASPRIA) provides a tool to simultaneously acquire information about brain structure and blood flow. However, the radial trajectory used limits the resolution and SNR, especially when the data is highly undersampled. In this work, an optimised 3D cone trajectory is presented with 3D golden means rotation to improve sampling at the k-space periphery whilst maintaining flexibility in spatiotemporal resolution. A locally low rank reconstruction was used to leverage spatiotemporal correlations and improve image quality. In vivo results showed considerable improvements in resolution and SNR over the radial approach. |
| 2745 | Computer 42
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Multi-2D ASL-MRA and super-resolution convolutional neural network for improved intracranial peripheral arteries visualization |
| Yuriko Suzuki1, Ioannis Koktzoglou2,3, Peter Jezzard1, and Thomas Okell1 | ||
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 3Pritzker School of Medicine, University of Chicago, Chicago, IL, United States |
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Keywords: Arterial spin labelling, Blood vessels, MRA The non-invasive nature of Arterial Spin Labeling (ASL) technique makes ASL-based intracranial dynamic MR angiography (MRA) a potential alternative to diagnostic X-ray digital subtraction angiography. In elderly and diseased patients with slower blood flow, however, the vessel visualization of distal peripheral arteries tends to be poor, as the repeatedly applied RF excitation pulses decrease ASL blood signal rapidly. In this study, we address such a limitation by using multiple 2D slice acquisition to reduce the saturation of arterial blood signal. Additionally, to avoid losing vessel conspicuity and sharpness with 2D slice acquisition, we apply a super-resolution convolutional neural network method. |
| 2746 | Computer 43
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Weakly supervised learning improves vascular territorial mapping of random vessel-encoded ASL |
| Yining He1 and Lirong Yan1,2 | ||
1Radiology, Northwestern University, Chicago, IL, United States, 2Neurology, University of Southern California, Los Angeles, CA, United States |
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Keywords: Arterial spin labelling, Perfusion This study proposed a weakly supervised learning algorithm for vascular territorial mapping with rVE-ASL. The territory maps generated by the proposed deep learning (DL) method was compared with the territories from the conventional rVE-ASL method by visual inspection and F1 score. Our initial results showed that the DL method outperformed the conventional rVE-ASL method in the vascular territory mapping with improved detection of VA territory. The DL method also provided reliable vascular territorial maps with reduced numbers of encodings, significantly reducing rVE-ASL scan time. These findings suggest that DL could be an effective approach for vascular territorial mapping of rVE-ASL. |
| 2747 | Computer 44
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Towards Look-Locker encoding as an arterial spin labeling mechanism: T1/B1+/perfusion mapping with MR Multitasking |
| Fardad M Serry1, Hsu-Lei Lee1, Shihan Qiu1,2, Yibin Xie1, Fei Han1,3, Hui Han1, and Anthony G Christodoulou1,2 | ||
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States, 3Siemens Medical Solutions, Los Angeles, CA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling, multitasking, Look-Locker, B1+, spin history, T1, blood, brain, IR-FLASH, inversion efficiency, white matter, gray matter We hypothesized that the Look-Locker (LL) effect can label arterial spins without the need for subtraction between different inversion schemes. We developed a multiple-flip-angle, non-selective-inversion MR multitasking brain scan to produce co-registered T1, B1+, and perfusion-weighted maps. Flow-sensitive LL fitting homogenized B1+ maps and produced flow maps combining features of time-of-flight angiography images and PCASL perfusion-weighted images. GM/WM flow ratios were similar to PCASL and the literature range. |
| 2748 | Computer 45
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Multiparameter estimation from DANTE-prepared multi-delay ASL using artificial neural network |
| Shota Ishida1, Yasuhiro Fujiwara2, Naoyuki Takei3, Yuki Matta4, Masayuki Kanamoto4, Hirohiko Kimura5,6, and Tetsuya Tsujikawa7 | ||
1Department of Radiological Technology, Faculty of medical sciences, Kyoto College of Medical Science, Nantan, Japan, 2Department of Medical Image Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan, 3GE Healthcare, Hino, Japan, 4Radiological center, University of Fukui Hospital, Eiheiji, Japan, 5Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan, 6Radiology section, National Health Insurance Echizen-cho Ota Hospital, Unyu, Japan, 7Department of Radiology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan |
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Keywords: Arterial spin labelling, Arterial spin labelling A simulation-based supervised neural network was developed for simple and robust parameter estimation from multi-delay DANTE-prepared arterial spin labeling (ASL). The network was trained using 15 million simulation data points. Accuracy and precision were compared between the proposed and conventional methods. The neural-network-based estimation presented higher accuracy and precision than the conventional method that used table lookup. A higher noise immunity was also observed with the proposed method. A simulation-based supervised neural network simplifies the estimation process of multiparametric ASL. The estimation performance of cerebral blood flow and arterial cerebral blood volume was particularly improved by the proposed method. |
| 2749 | Computer 46
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Fast, isotropic, whole head perfusion imaging using a Spin Echo Rotating In-Out Spiral with velocity selective arterial spin labeling |
| David Joseph Frey1, Jeffrey A. Fessler2, Douglas C. Noll1, and Luis Hernandez-Garcia1 | ||
1Radiology, University of Michigan, Ann Arbor, MI, United States, 2Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States |
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Keywords: Arterial spin labelling, New Trajectories & Spatial Encoding Methods We investigate the performance of a new and efficient k-space sampling scheme that presents several advantages for velocity selective ASL imaging by rotating 2D spirals about the kx and ky axis. This paper compares the new readout to a traditional Stack-of-spirals readout by evaluating SNR for perfusion weighted images and the accuracy of z-scores for ASL FMRI experiments. |
| 2750 | Computer 47
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Investigating systematic error in pseudocontinuous Arterial Spin Labelling estimates of cerebrovascular reactivity |
| Colette Clare Milbourn1 and Nicholas Paul Blockley1 | ||
1School of Life Sciences, University of Nottingham, Nottingham, United Kingdom |
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Keywords: Arterial spin labelling, Arterial spin labelling New clinical tools are needed for the diagnosis and prognosis of cerebrovascular diseases. Cerebrovascular Reactivity (CVR) is a potential marker for brain health and can be induced using stressors to the brain like a hypercapnia challenge and quantitatively mapped using pseudocontinuous Arterial Spin Labelling (pCASL). However, measurements of CVR using pCASL have been shown to vary depending on the parameters of the unbalanced pCASL preparation scheme used. In this study the effect of a diminished B1 at the labelling plane and changes in B0 during hyperventilation were investigated as the origin of this discrepancy. |
| 2751 | Computer 48
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Dedicated ICTGV-regularized Reconstruction for time-encoded ASL |
| Ingmar S. Sorgenfrei1, Koen Baas2, Stefan Spann1, Martin Uecker1, and Rudolf Stollberger1 | ||
1Institute of Biomedical Imaging, TU Graz, Graz, Austria, 2Department of Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands |
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Keywords: Arterial spin labelling, Brain Time-encoded Arterial Spin Labeling (teASL) enables time-efficient acquisition of multiple averages of multiple post-labeling-delay (PLD) perfusion-weighted images (PWIs). We developed a dedicated teASL reconstruction that employs Infimal Convolution of Total Generalized Variation (ICTGV) regularization directly on the PWIs. Using simulated and healthy volunteer data, the ICTGV reconstruction produced inherently denoised images and improved cerebral blood flow and arterial transit time maps compared to a SENSE reconstruction. Also, for an 8-fold accelerated in-vivo dataset, the ICTGV reconstruction still produced reasonable PWIs, which the SENSE reconstruction could not. Therefore, ICTGV reconstruction is promising for teASL and allows high acceleration with inherent denoising. |
| 2752 | Computer 49
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Optimizing background suppression for dual-module velocity-selective ASL and characterizing the temporal noise |
| Jia Guo1 | ||
1Bioengineering, University of California Riverside, Riverside, CA, United States |
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Keywords: Arterial spin labelling, Brain Background suppression (BS) was optimized for dual-module velocity-selective arterials spin labeling (dm-VSASL) using VS inversion (dm-VSI). Compared with the Siemens product pulsed ASL (PASL) and pseudo-continuous ASL (PCASL) labeling, dm-VSI with optimized BS produced significantly higher temporal SNR; and a better suppression of the temporal noise from background tissues was observed with dm-VSI labeling by analyzing the temporal noise level with respect to the BS level. Further investigation is needed to verify and understand these findings to take full advantage of the improved SNR performance of dm-VSASL. |
| 2753 | Computer 50
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Theoretical and experimental evaluation of the test and retest reliability of single- and multi-delay 3D pCASL |
| Xingfeng Shao1, Zixuan Liu1, Qinyang Shou1, Kay Jann1, and Danny JJ Wang1 | ||
1Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States |
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Keywords: Arterial spin labelling, Perfusion, test and retest reliability, multi-delay ASL The goal of this study is to evaluate the quantification accuracy and measurement reliability of single- and multi-PLD pCASL via both simulation and in-vivo test and retest data. CBF calculated by single-delay ASL achieved highest test and retest reliability as compared to 5-PLD ASL. However, CBF values may be under-estimated due to prolonged ATT. 5-PLD ASL can be used to quantify ATT and CBF simultaneously with slightly reduced test and retest reliability. Model-fitting approach is more preferrable than the weighted-delay approach in terms of both quantification error and reliability. |
| 2754 | Computer 51
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Total Generalized Variation (TGV) Constrained Reconstruction Improves Test-retest Reliability of High Resolution 3D pCASL in Children |
| Qinyang Shou1, Xingfeng Shao1, Kimberly Felix2, Rudolf Stollberger3, Megan M Herting2, and Danny JJ Wang1 | ||
1Laboratory of Functional MRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States, 2Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 3Institute of Biomedical Imaging, Graz University of Technology, Graz, Austria |
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Keywords: Arterial spin labelling, Brain We developed an accelerated multi-delay 3D pCASL scheme with high-resolution (iso-2mm), CAIPI acceleration and TGV reconstruction to achieve a ~9-minute protocol with 5 delays with 8 averages per delay. We tested the feasibility of this protocol on 19 pediatric subjects and found the proposed imaging protocol with TGV constrained reconstruction can improve the test-retest reliability of high-resolution 3D pCASL perfusion imaging in typically developing children compared to a standard segmented acquisition. |
| 2755 | Computer 52
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Subspace reconstruction of high temporal resolution arterial spin labeling angiography using a kinetic model |
| Qijia Shen1, Mark Chiew2,3,4, Wenchuan Wu4, and Thomas Okell4 | ||
1University of Oxford, Oxford, United Kingdom, 2Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 3Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 4Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom |
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Keywords: Arterial spin labelling, Arterial spin labelling 4D combined angiography and perfusion using radial imaging and arterial spin labelling (CAPRIA) allows dynamic angiograms to be reconstructed. However, the current approach uses a relatively long temporal window to ensure sufficient k-space coverage within each frame, resulting in abrupt changes between adjacent frames, and additional artefacts. In this work, we use a kinetic model of the angiographic signal to constrain the reconstruction of highly undersampled data. A subspace reconstruction was developed for compressed representation of signal during reconstruction for computational efficiency. In-vivo results showed smoother variation of the angiographic signal in the temporal dimension compared to the original approach. |
| 2756 | Computer 53
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A Mathematical Model for Velocity-Selective Arterial Spin Labeling |
| Thomas Liu1,2,3,4, Eric Wong1,2,3, Divya Bolar1,2, Conan Chen1,2,5, and Ryan Barnes1,5 | ||
1Center for fMRI, University of California San Diego, La Jolla, CA, United States, 2Department of Radiology, UCSD, La Jolla, CA, United States, 3Department of Psychiatry, UCSD, La Jolla, CA, United States, 4Department of Bioengineering, UCSD, La Jolla, CA, United States, 5Department of Electrical and Computer Engineering, UCSD, La Jolla, CA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling A mathematical model is presented that describes the arterial delivery function and cerebral blood volume components in velocity-selective arterial spin labeling. The model incorporates physiologically valid approximations of changes in acceleration and velocity along the vascular system. Applications of the model are shown using a set of example labeling and saturation profiles. |
| 2757 | Computer 54
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Measuring Microvascular Pulsatility with Short Bolus Duration (τ) VSASL |
| Conan Chen1,2, Ryan A. Barnes1,2, Eric C. Wong1,3, Thomas T. Liu1,3,4, and Divya S. Bolar1 | ||
1Center for fMRI, Department of Radiology, University of California San Diego, La Jolla, CA, United States, 2Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, United States, 3Department of Psychiatry, University of California San Diego, La Jolla, CA, United States, 4Department of Bioengineering, University of California San Diego, La Jolla, CA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling Pulsatile blood flow has been linked to structural damage to the cerebral microvasculature. Previous methods have successfully measured pulsatility in the arteries, but few methods exist to target the microvasculature where the damage is occurring. In this current work, we present a simple theoretical model for CBF pulsatility, apply the model to experimental data acquired in human subjects, and report in vivo microvascular pulsatility using VSASL. |
| 2758 | Computer 55
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Whole Brain Distortion-free 3D pseudo-Continuous Arterial Spin Labeling at 7T with Turbo FLASH, Optimized Labeling and Background Suppression |
| Chenyang Zhao1, Xingfeng Shao1, Qinyang Shou1, Samantha Ma2, Sayim Gokyar1, Christina Graf3, Rudolf Stollberger3, and Danny JJ Wang1,4 | ||
1Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 2Siemens Medical Solutions USA, Los Angeles, CA, United States, 3Institute of Biomedical Imaging, Graz University of Technology, Graz, Austria, 4Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States |
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Keywords: Arterial spin labelling, Arterial spin labelling, Perfusion The potential of 7T has not been fulfilled for pseudo-Continuous Arterial Spin Labeling (pCASL) because of challenges in labeling, background suppression (BS), and readouts. This study proposed a new labeling parameter, a superior BS pulse, and an accelerated and segmented 3D Turbo-FLASH (TFL) readouts. Despite the field inhomogeneity at 7T, the new labeling parameter achieves high labeling efficiency without signal interference, and OPTIM as BS pulse robustly achieves high inversion efficiency. 3D TFL pCASL provides whole brain coverage, abundant anatomical information without distortion, high resolution, and sufficient SNR in 11 mins. |
| 2759 | Computer 56
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Spatiotemporal redundancy based denoising method in arteprial spin labeling MRI: A ticket to free sensitivity improvement |
| Xinran Chen1, Liangjie Lin2, Zhiliang Wei3, Lin Chen1, and Zhong Chen1 | ||
1Department of electronic science, Xiamen University, Xiamen, China, 2Clinical & Technical Support, Philips Healthcare, Beijing, China, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: Arterial spin labelling, Data Processing, Denoising Arterial-spin-labeling (ASL) MRI has been widely used in neurological studies for investigating brain activity via focusing on regional perfusion differences. However, sensitivity is a general issue in ASL MRI to prevent the high-resolution comparisons of perfusion heterogeneity, which are associated with pathological process, or lead to prolonged scan time, which inhibits the temporal resolution in monitoring acute-stage perfusion changes (e.g., perfusion recovery after spontaneous resuscitation in cardiac arrest). Therefore, in this study, a post-processing method exploring spatiotemporal redundant information of ASL data is proposed to enhance the sensitivity without extending scan durations. |
| 2760 | Computer 57
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Feasibility Study to Spatially Map the Filtration Function of the Kidneys with Multi-TE Arterial Spin Labeling |
| Lena Sommer1, Daniel Christopher Hoinkiss1, Jörn Huber1, Simon Konstandin1,2, and Matthias Günther1,2,3 | ||
1Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany, 2mediri GmbH, Heidelberg, Germany, 3University of Bremen, Bremen, Germany |
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Keywords: Arterial spin labelling, Kidney A spatial mapping of the renal filtration function of the blood might be helpful in identifying parts of the kidney that only work with reduced function and are therefore impaired the most. This work shows an approach to a non-invasive method to map the filtration rate of the kidney. |
| 2761 | Computer 58
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A novel approach to derive robust arterial input functions for DCE-MRI in small animals |
| Ebony Rosalind Gunwhy1, Sirisha Tadimalla2, John C. Waterton3,4, Paul D. Hockings5,6, Gunnar Schütz7, Claudia Green7, J. Gerry C. Kenna4, and Steven Sourbron1 | ||
1Department of Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, United Kingdom, 2Institute of Medical Physics, The University of Sydney, Sydney, Australia, 3Centre for Imaging Sciences, Division of Informatics Imaging & Data Sciences, School of Health Sciences, Faculty of Biology Medicine & Health, University of Manchester, Manchester, United Kingdom, 4Bioxydyn Ltd, Manchester Science Park, Manchester, United Kingdom, 5BioVentureHub, Antaros Medical, Mölndal, Sweden, 6MedTech West, Chalmers University of Technology, Gothenburg, Sweden, 7MR & CT Contrast Media Research, Bayer AG, Berlin, Germany |
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Keywords: Validation, Animals, Arterial input functions, small animals, spleen, liver Accurate biomarker quantification is hindered in small animal MRI due to difficulties in reliably deriving arterial input functions (AIFs). This study provides a robust alternative to commonly used approaches by deriving AIFs from a simple, whole-body circulation model. This method is compared with individual and population spleen-derived AIFs by evaluating performance in gadoxetate DCE-MRI of the rat liver. Results demonstrated that the whole-body circulation model-derived AIF yields greater repeatability, reproducibility, and goodness-of-fit to observed data, indicating that it provides more accurate biomarker quantification than the individual or population spleen-derived AIFs. |
| 2762 | Computer 59
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The choroid plexus as a source for selecting an arterial input function for resting cerebral perfusion measures |
| Olivia Sobczyk1, Ece Su Sayin2, Julien Poublanc1, Harrison Toby Levine2, James Duffin2, Joseph Arnold Fisher2, and David John Mikulis1 | ||
1University Health Network, Toronto, ON, Canada, 2Physiology, University of Toronto, Toronto, ON, Canada |
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Keywords: Susceptibility, Perfusion The choroid plexus is composed of arteries and stroma with negligible metabolic activity allowing its vessels to remain arterialized throughout its structure. We assessed the choroid plexus as a suitable alternate arterial input function rather than the middle cerebral artery in DSC imaging in individuals with both normal vasculature and pathology affecting the middle cerebral artery. |
| 2763 | Computer 60
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A deep learning approach for robust and accurate deconvolution of DSC MRI perfusion calculation |
| Muhammad Asaduddin1, Eung Yeop Kim2, and Sung-Hong Park1 | ||
1Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of, 2Department of Radiology, Samsung Medical Center, Sungkyunkwan University College of Medicine, Seoul, Korea, Republic of |
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Keywords: Contrast Agent, DSC & DCE Perfusion The conventional deconvolution method in DSC perfusion MRI suffers from sensitivity to noise and threshold level. Regularization methods to mitigate the noise issue also suffers from other issues. In this study, we present a deep learning approach to perform deconvolution more robustly and accurately. Our result showed multi layers perceptron (MLP) performed deconvolution more accurately in synthetic data compared to the traditional regularization method. We also showed that MLP performed more robustly in patient data with varying levels of noise. This study provides a strong argument for using MLP as a stable and accurate deconvolution method for DSC perfusion calculation. |
| 2979 | Computer 101
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Characterization of glycogen storage disease type III using glycoNOE MRI |
| Qing Zeng1,2, Chongxue Bie1,2, Peter C.M. van Zijl1,2, Yuguo Li1,2, Valentina D'souza1,2, Michael Machado3, Kirsten Achilles Poon3, Andrew Grimm3, and Nirbhay N. Yadav1,2 | ||
1The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Ultragenyx Pharmaceutical Inc., Novato, CA, United States |
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Keywords: CEST & MT, CEST & MT, liver Glycogen storage disease type III (GSD III) is characterized by abnormally high glycogen accumulation in liver, muscle, and heart. Treatments such as diet modification and drugs are currently being developed, but there is a lack of suitable methods for assessing disease load and possible treatment efficacy. Recently, it was shown that glycoNOE MRI can image glycogen levels in vivo and here we apply this technique to distinguish GSD III from controls in a mouse model. The results show that glycoNOE can clearly distinguish GSD III and that glycoNOE contrast exhibits a linear correlation with ex vivo quantification of glycogen levels. |
| 2980 | Computer 102
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Dynamic Glucose Enhanced MRI of Brain Tumors using Direct Water Saturation |
| Peter van Zijl1, Nirbhay Yadav2, Sajad Mohammed Ali3, Anina Seidemo3, David Olayinka Kamson4, Lindsay Blair5, John Laterra6, and Linda Knutsson7 | ||
1Radiology, F.M. Kirby Research Center, Johns Hopkins University, Kennedy Krieger Institute, Baltimore, MD, United States, 2Radiology/F.M. Kirby Research Center, Johns Hopkins University, Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Medical Radiation Physics, Lund University, Lund, Sweden, 4Department of Oncology, Johns Hopkins University, Baltimore, MD, United States, 5Neurology, Johns Hopkins University, Baltimore, MD, United States, 6Neurology, Johns Hopkins University, Kennedy Krieger Institute, Baltimore, MD, United States, 7F.M. Kirby Research Center, Radiology, Medical Radiation Physics, Kennedy Krieger Institute, Johns Hopkins University, Lund University, Baltimore, MD, United States |
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Keywords: CEST & MT, Cancer, Glucose The transverse relaxation time (T2) of water is affected by the presence of exchangeable protons that are chemically shifted with respect to the water protons. We use direct saturation (DS) MRI to dynamically measure this effect during infusion of D-glucose to assess its uptake in brain tumors. The change in T2 becomes apparent as a line broadening of the DS spectrum, which is acquired using a whole-brain water saturation shift reference (WASSR) acquisition. First results using 0.5g/kg D-glucose show linewidth changes on the order of a few Hertz in glioma patients, allowing separation of tumor tissue from healthy brain tissue. |
| 2981 | Computer 103
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Towards Metabolic Brain Imaging with Glucosamine CEST MRI: In Vivo Characterization and First Insights |
| Michal Rivlin1, Or Perlman2,3, and Gil Navon1 | ||
1School of Chemistry, Tel-Aviv University, Tel Aviv, Israel, 2Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel, 3Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel |
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Keywords: CEST & MT, Brain, Glucosamine, MRI, CEST, Metabolism, Brain Disorders The uptake of glucosamine (GlcN), a non-toxic food supplement, can be monitored by CEST MRI. While previously demonstrated in breast cancer, here we show that GlcN metabolism can be detected in the brain. Following GlcN administration in mice, the MTRasym signals were significantly elevated in the cortex, hippocampus, and striatum. A Lorentzian multi-pool fitting pointed to a significant increase in the hydroxyl, amide, and rNOE signals. An in vitro BSA study confirmed the interactions between brain compounds and GlcN shown in vivo. This study suggests that GlcN CEST has the potential to serve as a metabolic biomarker in brain disorders. |
| 2982 | Computer 104
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Evaluation of Biological Metabolic Activity within an Atherosclerotic Plaque using Chemical Exchange Saturation Transfer Imaging |
| Yuki Kanazawa1, Tosiaki Miyati2, Masafumi Harada1, Mitsuharu Miyoshi3, Yuki Matsumoto1, Hiroaki Hayashi2, Yasuhisa Kanematsu1, and Yasushi Takagi1 | ||
1Tokushima University, Tokushima, Japan, 2Kanazawa University, Kanazawa, Japan, 3Global MR Applications and Workflow, GE Healthcare Japan, Hino, Japan |
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Keywords: CEST & MT, Atherosclerosis We demonstrated biological metabolic activity within an atherosclerotic plaque of the carotid artery using CEST imaging. 35 patients with carotid stenosis, of which all were pathologically diagnosed with carotid endarterectomy, were evaluated. The following estimation parameters in CEST image were evaluated; bulk water, magnetization transfer, amide proton transfer (APT), and nuclear Overhauser effect (NOE). As a result, there were weak positive correlations between T1w-signal-ratio and the above-mentioned parameters: bulk water (R = 0.37), APT (R = 0.39), and NOE (R = 0.37). Multi-parametric analysis of CEST imaging can obtain detailed information concerning the activity in an atherosclerotic plaque. |
| 2983 | Computer 105
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PUSHUP-CEST: Calibration free homogeneous saturation for ulta-high field CEST imaging |
| Yannik Völzke1, Rüdiger Stirnberg1, Eberhard Pracht1, Daniel Löwen1, Vincent Gras2, Nicolas Boulant2, Moritz Zaiss3, and Tony Stöcker1,4 | ||
1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, 2Université Paris-Saclay, Commissariat à l’Energie Atomique, CNRS, NeuroSpin, Baobab,, Gif sur Yvette, France, 3Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander- Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 4Department of Physics and Astronomy, University of Bonn, Bonn, Germany |
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Keywords: CEST & MT, CEST & MT CEST imaging benefits from the increased spectral resolution at ultra-high field. Due to the inhomogeneous RF field, a B1+-correction is necessary, which requires repeated measurements. The number of required repetitions can be reduced to two by using a ptx-based saturation scheme, like MIMOSA. We present an alternative saturation scheme that is based on PUSH saturation and universal pulses, which we name PUSHUP. Using this approach, we could reduce the inhomogeneity of the CEST saturation as effectively as MIMOSA while being more SAR efficient. |
| 2984 | Computer 106
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Highly Accelerated Chemical Exchange Saturation Transfer Imaging with Partially Separable Network |
| Chuyu Liu1, Zhensen Chen2, and Xiaolei Song1 | ||
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China, 2Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China |
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Keywords: CEST & MT, Machine Learning/Artificial Intelligence Herein, we developed a partially separable network (PSN) for CEST acceleration. Our contributions are: 1) We found that the reconstruction error of CEST mainly exists in the spatial subspace. 2) A deep learning network based on partially separable model was developed to optimize CEST images in spatial subspace. Retrospective results suggested that our method enabled a highly accelerated CEST imaging (14X for healthy adults and 11X for brain tumor patients) with contrast maps and Z-spectrum consistent with gold standard, which could have great clinical utility. |
| 2985 | Computer 107
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Joint Model-Based Optimization of Sampling Pattern and Reconstruction for Human Brian CEST MRI at 3T |
| Chuyu Liu1, Zhongsen Li1, and Xiaolei Song1 | ||
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China |
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Keywords: CEST & MT, Machine Learning/Artificial Intelligence Here we introduced a model-based deep learning approach which enabled joint optimization of both sampling and reconstruction for CEST MRI. The main purpose is to investigate an efficient undersampling pattern for CEST acceleration. Retrospective results (4X) showed that the proposed workflow is capable of leveraging redundancy information from optimized sampling pattern, further reconstructing gold-standard-consistent contrast maps. |
| 2986 | Computer 108
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Prospective acceleration of whole-brain chemical exchange saturation transfer by Joint K-space and Image-space Parallel Imaging (KIPI) |
| Tao Zu1, Zhechuan Dai1, Xingwang Yong1, Tongling Jiang1, and Yi Zhang1 | ||
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China |
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Keywords: CEST & MT, Parallel Imaging The clinical use of chemical exchange saturation transfer (CEST) imaging is limited by its relatively long scan time due to the measurements of multiple frames at the same location, especially for 3D whole-brain imaging. In this study, the recently proposed reconstruction method by joint K-space and Image-space Parallel Imaging (KIPI) is utilized for prospectively accelerating 3D CEST imaging. Prospective KIPI allows an acceleration factor of up to 8-fold for acquiring source images, reducing the scan time to 5.5 min for the whole-brain quantitative CEST imaging, with 17 saturation frames and 2.9 mm isotropic resolution. |
| 2987 | Computer 109
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Metabolic Imaging of malignant gliomas during immunotherapeutic intervention using chemical exchange saturation transfer (CEST) MRI at 9.4T |
| Kianush Karimian-Jazi1,2, Volker Sturm1, Katharina Schregel1,2, Jessica Hunger1,3, Verena Turco3,4, Noah Enbergs1, Berin Boztepe1,3, Manuel Fischer1, Yannik Streibel1, Nikolaus von Knebel-Doeberitz5, Andreas Korzowski6, Steffen Görke6, Florian Kroh6, Mark E. Ladd6, Heinz-Peter Schlemmer5, Daniel Paech5,7, Christopher B. Rodell8, Michael Platten3,4, Wolfgang Wick2,9, Sabine Heiland1, Martin Bendszus1, and Michael O. Breckwoldt1,3 | ||
1Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany, 2Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DTK) within the German Cancer Research Center (DKFZ), Heidelberg, Germany, 3Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology, German Cancer Consortium (DTK) within the German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Department of Neurology, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, 5Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 6Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 7Clinic for Neuroradiology, University Hospital Bonn, Bonn, Germany, 8School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States, 9Department of Neurology, Heidelberg University Hospital, Heidelberg, Germany |
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Keywords: CEST & MT, High-Field MRI, Glioma CDNP-R848, an experimental immunotherapeutic TLR7/8 agonist, showed high treatment efficacy with a significant tumor volume reduction and led to a re-normalization of the metabolic properties (MTRex Amide, MTRex Amine and MTRex NOE) of the tumor in relation to the healthy brain, with distinct differences to vehicle treatment. The clinical relevance of CEST imaging appears to be localizing active tumor areas and a better understanding of tumor heterogeneity. In the future, we aim to better characterize the origin of the CEST contrast by correlated histological and spatial metabolic analysis. |
| 2988 | Computer 110
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The exchange rate of creatine CEST in mouse brain |
| Ziqin Zhang1,2, Kexin Wang1,2, Sooyeon Park2,3, Anna Li2, Yuguo Li2,4, Robert Weiss4,5, and Jiadi Xu2,4 | ||
1Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States, 3Department of Neuroscience, Johns Hopkins University, Baltimore, MD, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT, amide CEST, amine CEST, guanidinium CEST, creatine CEST, exchange rate, concentration, polynomial Lorentzian line-shape fitting (PLOF), high spectral resolution (HSR) CEST, two-step Bloch-McConnell (BM) fitting. We aim to use three different approaches to estimate the exchange rate of creatine (Cr) CEST, i.e., the pure CrCEST line-shape, B1-dependent CrCEST, and the pH response with different B1 values. The pure CrCEST signal extracted using wild type and GAMT-/- mice with low Cr and PCr concentrations; the pH in the brain cells altered by hypercapnia to demonstrate the pH sensitivity of GuanCEST; a two-step Bloch-McConnell fitting implemented to quantify the exchange rates. in vivo CrCEST exchange rate was found slow (~260-350 s-1). CrCEST is the major contribution to the opposite pH-dependence of GuanCEST signal under different B1. |
| 2989 | Computer 111
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Z-spectral fitting for fat-correction of APT/CEST-MRI including fat-suppression pulses to improve body applications |
| Jochen Keupp1, Ivan E. Dimitrov2,3, Holger Eggers1, and Elena Vinogradov3,4 | ||
1Philips Research, Hamburg, Germany, 2Philips Healthcare, Gainesville, FL, United States, 3Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 4Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States |
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Keywords: CEST & MT, Fat, Z-spectral fitting, Fat suppression pulses Fat signal correction remains a challenge in APT/CEST-MRI for body-oncology. We show that signal background models that include direct water saturation, MT-effect, and modified fat spectra can be fitted to Z-spectra acquired with/without fat-suppression. APT/CEST signals are then extracted as the residual from the background fit (APT#). The model for fat-suppressed spectra uses a mirrored fat contribution. After B0-correction, 5 model parameters are sufficient. This allows for the acquisition of clinically feasible protocols using less than 20 Z-spectral offsets. Fat-suppression potentially increases the precision of APT# imaging by lowering the initial fat contribution. |
| 2990 | Computer 112
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Imaging Extracellular Lactate with Lanthanide-PCTA-based PARACEST Agents |
| Remy Chiaffarelli1,2, Paul Jurek3, Pedro Cruz4, Max Zimmermann1,2, Carlos Geraldes4, Garry Kiefer3, and André Ferreira Martins1,2 | ||
1Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University Hospital Tuebingen, Tuebingen, Germany, 2Cluster of Excellence iFIT (EXC 2180) “Image-Guided and Functionally Instructed Tumor Therapies”, University of Tuebingen, Tuebingen, Germany, 3Macrocyclics, Inc., Plano, TX, United States, 4Coimbra Chemistry Center - Institute of Molecular Sciences (CQC-IMS), University of Coimbra, Coimbra, Portugal |
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Keywords: CEST & MT, CEST & MT, PARACEST, Metabolism Lactate accumulation in the tumor microenvironment is a hallmark of cancer aggressiveness. Here, we report a method to image extracellular lactate using shiftCEST MRI and Yb- and EuPCTA Shift Reagents (SRs). In the presence of lactate, the SRs shift the lactate OH-CEST signal away from the water signal by ~14 ppm (EuPCTA) and ~95 ppm (YbPCTA), allowing for quantitative detection of extracellular lactate produced by cancer cells. In vivo studies confirmed the detection and fast renal elimination of the lactate*YbPCTA into the bladder by shiftCEST MRI. Overall, these results provide new insights into developing innovative non-invasive metabolic MRI. |
| 2991 | Computer 113
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In silico optimization of iopamidol CEST MRI for renal pH mapping at 3 Tesla |
| Julia Stabinska1,2, Moritz Zaiss3,4, Adnan Bibic1, Farzad Sedaghat2, Cristina L Sadowsky5,6, Peter CM van Zijl1,2, and Michael T McMahon1,2 | ||
1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 2The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 4Institute of Neuroradiology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany, 5International Center for Spinal Cord Injury, Kennedy Krieger Institute, Baltimore, MD, United States, 6Physical Medicine and Rehabilitation, The Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT In vivo optimization of CEST iopamidol contrast in human subjects is complicated and requires multiple examinations and injections of the agent. To address this challenge, we propose application of a numerical approach that utilizes exchange rates determined under physiological conditions at 17.6T to perform kidney-like multi-pool Bloch-McConnell simulations for in silico optimization of saturation parameters for 3T applications. Our results suggest that the iopamidol-based CEST MRI is sensitive to pH in the range between 6 and 7.2 with the optimal results when short CEST saturation pulses (3x100 ms), low B1 strength (B1~0.8 µT) and short recovery time (Trec~T1w) are applied. |
| 2992 | Computer 114
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Learned spatiotemporal correlation priors for CEST image denoising using incorporated global-spectral convolution neural network |
| Huan Chen1, Liangjie Lin2, Lin Chen1, and Zhong Chen1 | ||
1Department of Electronic Science, Xiamen University, Xiamen, China, 2Clinical & Technical Support, Philips Healthcare, Beijing, China |
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Keywords: CEST & MT, Machine Learning/Artificial Intelligence Chemical exchange saturation transfer (CEST) MRI is a versatile technique that exploits the saturation transfer between exchangeable protons and water for non-invasive detection of diluted metabolites. Although theoretically promising, the practical application of CEST MRI is still challenged by low CEST contrast and low signal-to-noise ratio (SNR) of acquired images. Here, we proposed a deep learning-based method, dubbed denoising CEST network (DCEST-Net), to fully exploit the spatiotemporal correlation prior embedded in the CEST images and restore noise-free images from their noisy observations. Results suggested that DCEST-Net can achieve better performance compared to the state-of-the-art denoising methods. |
| 2993 | Computer 115
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The exchange rates of protein guanidinium protons in the mouse brain |
| Kexin Wang1,2, Ran Sui1,2, Lin Chen3,4, Yuguo Li2,3, and Jiadi Xu2,3 | ||
1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 4Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China |
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Keywords: CEST & MT, Alzheimer's Disease, GuanCEST We develop a novel two-step multi-B1 Bloch-McConnell fitting approach for calculating the exchange rate of CEST protons in vivo, and apply it to guanidinium protons, the exchange rate of which is 70.1 ± 5.5 s-1 with a concentration of 40.4 ± 5.2 mM in mouse brain at an optimized B1 of 0.8 µT. Guanidinoacetate N-methyltransferase deficiency (GAMT-/-) mice that have low creatine and phosphocreatine concentrations in brain are studied for protein guanidinium, i.e., arginineCEST (ArgCEST). The low exchange rate of ArgCEST suggests that the inverse pH dependence in GuanCEST with low B1 is dominated by CrCEST compared to ArgCEST. |
| 2994 | Computer 116
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CEST effect of dimethyl sulfoxide (DMSO) at negative offset frequency |
| Haoyun Su1,2, Jianpan Huang1, and Kannie W.Y. Chan1,2,3,4,5 | ||
1Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, 2Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), New Territories, Hong Kong, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4City University of Hong Kong Shenzhen Research Institute, Shenzhen, China, 5Tung Biomedical Sciences Centre, City University of Hong Kong, Kowloon, Hong Kong |
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Keywords: CEST & MT, Molecular Imaging CEST MRI can detect mM range of endogenous and exogenous molecules, and bound small molecules such as glycogen and lactate via rNOE. Here we reported for the first time that DMSO and its structural analogs in aqueous solution had distinctive CEST peaks at the negative offsets of Z-spectrum. CEST effect of DMSO was dependent on saturation power and concentration, and less sensitive to tested temperature. Alcohols, acetone, acetonitrile, acetic acid and N,N-dimethylformamide also showed observable CEST peaks at the negative offsets. Interaction between DMSO and water molecule, such as hydrogen bonding, could contribute to the observed CEST effect. |
| 2995 | Computer 117
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Subspace denoising for CEST MRI with non-local low-rank constraint and spectral-smoothness regularization |
| Xinran Chen1, Jian Wu1, Liangjie Lin2, Zhiliang Wei3, Lin Chen1, and Zhong Chen1 | ||
1Department of electronic science, Xiamen University, Xiamen, China, 2Clinical & Technical Support, Philips Healthcare, Beijing, China, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: CEST & MT, Data Processing, Denoising Chemical exchange saturation transfer (CEST) is a powerful technique that enables non-invasive detection of endogenous metabolites in living tissues. Since the observed water signal is decreased due to the transfer of saturated spins, CEST imaging inherently suffers from low SNR, hence degrading accuracy and reproducibility. Inspired by the spatial-spectral correlation of CEST images, here we propose a Subapace denoising method with Non-Local Low-Rank constraint and Spectral-Smoothness regularization (SNLRSS) to diminish the noise, which improves the accuracy of subsequent quantitative analyses of CEST images. |
| 2996 | Computer 118
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Imaging treatment efficacy of repeated photodynamic therapy in glioblastoma using CEST MRI |
| Vivian W.M. Leung1, Joseph H.C. Lai1, Zilin Chen1, Jianpan Huang1, Se Weon Park1,2, Yang Liu1,2, Charles Hu3, and Kannie W. Y. Chan1,2,4,5,6 | ||
1Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China, 2Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China, 3Incando Therapeutics Pte Ltd, Singapore, Singapore, 4Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5City University of Hong Kong Shenzhen Research Institute, Shenzhen, China, 6Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong, China |
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Keywords: CEST & MT, Tumor Glioblastoma (GBM) is hard to treat and has poor prognosis. Photodynamic therapy (PDT) is a promising treatment for GBM. Here, we detect the treatment efficacies of different PDT schemes (repeated (re-) and single (s-) PDT) on a rodent model of GBM using CEST MRI to monitor the molecular changes associated with tumor physiology and necrosis. Significant decreases in APT and rNOE signals were detected in the rePDT group as well as decreased proliferative activities in histology when compared with sPDT. This indicates that both APT and rNOE can be a reliable approach to assess PDT treatment efficacy against GBM. |
| 2997 | Computer 119
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Memorizing Transformer for Small-scale Multi-parametric MRI Brain Tumor Diagnosis |
| Yiqing Shen1,2, Nhat Le1,2, Jingpu Wu1,3, Pengfei Guo1,2, Jinyuan Zhou1, Mathias Unberath2, and Shanshan Jiang1 | ||
1Department of Radiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States, 2Department of Computer Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States, 3Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: CEST & MT, Machine Learning/Artificial Intelligence Deep learning approaches have been widely applied to the MRI field. Among them, transformers have received increasing popularity due to their capability in handling multi modalities. Yet, transformers are hungry for large-scale data, which is expensive to collect. Here, we develop a novel memorizing transformer for small-scale multi-parametric MRI analysis. Empirically, we evaluate the proposed method on a dataset curated from 147 brain post-treatment malignant glioma cases for classifying treatment effect and tumor recurrence. The proposed memorizing transformer boosted a 5.15% improvement in the test area under the receiver-operating-characteristic curve (AUC) to the baseline transformer approaches. |
| 2998 | Computer 120
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Quantitative volumetric mapping of intracellular pH in the human brain at 7 T using endogenous CEST-MRI: A proof of principle study |
| Philip S Boyd1, Florian Kroh1,2, Johannes Breitling1, Vanessa L Franke1,2, Mark E Ladd1,2,3, Peter Bachert1,2, Steffen Goerke1, and Andreas Korzowski1 | ||
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany, 3Faculty of Medicine, University of Heidelberg, Heidelberg, Germany |
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Keywords: CEST & MT, Molecular Imaging, intracellular pH, guanidyl protons, 7 Tesla In this study, our method for quantitative pHi mapping using endogenous CEST-MRI was successfully transferred to examinations of the human brain at B0=7T. Applicability in vivo was demonstrated in n=3 healthy volunteers, showing an overall median pHi,CEST of 7.00 and 6.96 for gray and white matter, respectively. In order to proof the plausibility of the presented approach, the obtained pHi,CEST maps were additionally validated directly in vivo via 31P MRSI at 7T, showing an overall median pHi,31P of 7.02 and 7.01 for gray and white matter, respectively. Consequently, reliable CEST-based pHi mapping is now also possible in the human brain. |
| 3156 | Computer 101
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3D Steady-State Golden Angle Radial Sparse Parellel CEST (ssGraspCEST) MRI of the human brain at 3T. |
| Rodolphe Leforestier1, Ding Xia1, Li Feng1, and Xiang Xu1 | ||
1Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States |
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Keywords: CEST & MT, CEST & MT The purpose of this project was to study the applicability of a fast 3D CEST MRI technique called GraspCEST to extract amdie, guanidinium and rNOE CEST contrasts in human brain at 3T. |
| 3157 | Computer 102
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Optimization of Saturation Power for pH-enhanced MRI in Stroke Rodents |
| Julius Juhyun Chung1 and Tao Jin1 | ||
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States |
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Keywords: CEST & MT, CEST & MT The sensitivity of CEST to pH makes it a potential modality for the assessment of intracellular pH alterations under pathologic conditions. We previously introduced a method for pH-enhanced MRI using amide and guanidyl protons. In this study, we determine saturation powers for imaging both exchangeable protons to optimize either contrast or contrast-to-variation ratio (CVR) between healthy and infarcted tissue in stroke rats. The contrast across parameters remained steady at ~2-3%, while CVR was dominated by variation across ROIs due to residual non-specific contrast. Optimizing CVR minimizes contrast within the lesion and contralesional tissue while preserving contrast between the two tissues. |
| 3158 | Computer 103
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Adjustment of Saturation and Rotation Effects (AROSE) for CEST Imaging |
| Tao Jin1 and Julius Juhyun Chung1 | ||
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States |
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Keywords: CEST & MT, CEST & MT Endogenous CEST signal usually has low specificity due to contamination from the magnetization transfer (MT) effect and from other labile protons with close Larmor frequencies. We propose to improve CEST signal specificity with AROSE which measures the difference between CEST signals acquired with similar average saturation power but largely different duty cycles (DC), e.g., a continuous wave or a high DC pulse train versus a low DC one. Simulation and creatine phantom studies showed that AROSE can improve the specificity of slow to intermediate exchanging CEST signals with relatively limited loss of sensitivity. |
| 3159 | Computer 104
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Development of in vivo quantitative gluCEST fitting using quantitative 1H-MRS as a reference in the mouse brain |
| Cécile Maguin1, Eloïse Mougel1, Julien Valette1, and Julien Flament1 | ||
1Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-roses, France |
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Keywords: CEST & MT, Modelling, Quantitative imaging In this work, we propose to quantify glutamate with CEST imaging. We use quantitative magnetic resonance spectroscopy as a standard method to measure glutamate concentration in the mouse striatum, and build a CEST model optimized for high saturation power to properly fit glutamate concentration. The CEST estimator developed in this way allowed us to recover glutamate concentration with an average error of 0.7 mM. |
| 3160 | Computer 105
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Comparison of pH-weighted and conventional MRI signal in ischemic stroke |
| Tao Jin1, Jicheng Wang2, T. Kevin Hitchens3, Dandan Sun4, Andriy Bandos5, Joseph Mettenburg1, Ping Wang1, and Julius Juhyun Chung1 | ||
1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2Department of Urology, University of Pittsburgh, Pittsburgh, PA, United States, 3Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States, 4Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States, 5Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, United States |
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Keywords: CEST & MT, Stroke, APT, Penumbra The sensitivity of APT MRI in the evaluation of ischemic tissue status was evaluated in stroke rat brains and compared with conventional MRI methods. APT can detect the different levels of tissue acidosis in the ischemic core, penumbra, and oligemia regions. Additionally, APT can also differentiate the severity of tissue acidosis associated with different blood glycemic levels. Our results indicate that APT MRI is a sensitive pH-weighted imaging marker with great potential for the evaluation of the ischemic tissue status and prediction of the stroke outcome. |
| 3161 | Computer 106
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Simultaneous mapping of glycogen and phosphocreatine in human skeletal muscle by saturation transfer MRI |
| Chongxue Bie1,2, Chao Zhou1, Peter C. M. van Zijl3,4, Nirbhay N. Yadav3,4, Yin Wu1, Hairong Zheng1, and Yang Zhou1 | ||
1Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Department of Information Science and Technology, Northwest University, Xi’an, China, 3F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 4The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: CEST & MT, Metabolism Glycogen and phosphocreatine (PCr) are essential metabolites for maintaining cellular ATP levels. Recent reports show the possibility of PCr mapping in skeletal muscle using CEST MRI but glycogen levels measured using this approach have been inconclusive. Here we report the high-resolution mapping of glycogen and PCr in human skeletal muscle based on relayed nuclear Overhauser effects (glycoNOE) and CEST, respectively. Results at 5T show homogeneous distributions of glycogen and PCr in the calf at levels corresponding to biopsy. Exciting possible applications include localized studies of cellular energetics and noninvasive in situ evaluation of exercise and muscle metabolism in humans. |
| 3162 | Computer 107
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The impact of motion and motion correction in dynamic glucose enhanced MRI |
| Patrick M. Lehmann1, Christos Papageorgakis2, Stefano Casagranda2, Anina Seidemo1, Xiang Xu3,4, Nirbhay N. Yadav4,5, Xu Li4,5, Ronnie Wirestam1, Patrick Liebig6, Frederik Testud7, Pia C. Sundgren8,9,10, Peter C.M. Van Zijl4,5, and Linda Knutsson1,4,5 | ||
1Medical Radiation Physics, Lund University, Lund, Sweden, 2Department of R&D Advanced Applications, Olea Medical, La Ciotat, France, 3BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 6Siemens Healthcare GmbH, Erlangen, Germany, 7Siemens Healthcare AB, Malmö, Sweden, 8Department of Radiology, Lund University, Lund, Sweden, 9Lund University Bioimaging Centre, Lund University, Lund, Sweden, 10Department of Medical Imaging and Physiology, Skane University Hospital, Lund, Sweden |
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Keywords: CEST & MT, Motion Correction Dynamic glucose-enhanced (DGE) MRI is a dynamic chemical exchange saturation transfer (CEST) method that can provide information about D-glucose uptake in tissue. DGE signal changes are small and so-called pseudo-DGE effects can appear as true DGE effects. In this study, we investigated how motion and motion correction influenced the DGE effects using both a realistic (measured) motion pattern and an arbitrary motion pattern. We observed that pseudo-DGE effects are governed by the head motion pattern and originate either from tissue mixing at tissue interfaces or B0-shifts. Although motion correction can reduce these effects, new pseudo-DGE effects can also be introduced. |
| 3163 | Computer 108
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Reproducibility of pH-Weighted Chemical Exchange Saturation Transfer (CEST) Contrast in the Healthy Cervical Spinal Cord |
| Alicia Cronin1,2, Patrick Liebig3, Sarah Detombe4, Neil Duggal1,4, and Robert Bartha1,2 | ||
1Medical Biophysics, Western University, London, ON, Canada, 2Centre for Functional and Metabolic Mapping, Robarts Research Institute, London, ON, Canada, 3Siemens Healthcare GmbH, Erlangen, Germany, 4Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, ON, Canada |
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Keywords: CEST & MT, Spinal Cord Ischemia and hypoxia can occur in the spinal cord due to several conditions, including compression and injury; however, in-vivo measurements of ischemia have been challenging. Chemical Exchange Saturation Transfer (CEST) can produce pH-weighted contrast, which is an indicator of tissue hypoxia. The purpose of this study was to optimize pH-weighted CEST contrast in the healthy cervical spinal cord using a prototype 3D CEST sequence on a 3T Siemens Prisma Fit MRI and determine the reproducibility of measurements at various levels along the cervical spinal cord. |
| 3164 | Computer 109
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CEST Mapping from Undersampled Z-spectra in the Brain Using Deep Learning |
| Karandeep S Cheema1,2, Pei Han1, Hsu-Lei Lee1, Hui Han1, Yibin Xie1, Anthony Christodoulou1,2, and Debiao Li1,2 | ||
1Cedars Sinai Medical Center, Los Angeles, CA, United States, 2Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States |
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Keywords: CEST & MT, Machine Learning/Artificial Intelligence, CEST, frequency offsets, Fisher Information gain Chemical exchange saturation transfer (CEST) imaging uses radio frequency pulses at different frequency offsets to generate CEST maps. In this work, we used deep learning to calculate CEST maps from steady-state CEST (ss-CEST) images at undersampled frequency offsets, reducing the total scan time by a factor of 3.5. The Z-spectrum was undersampled by selecting the top 15 frequency offsets from Fisher information gain analysis. Fitting results from the proposed method were compared with those from multi-pool fitting with fully sampled Z-spectrum. We showed that it is feasible to reconstruct CEST maps from undersampled, field uncorrected ss-CEST images. |
| 3165 | Computer 110
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A Steady State Free Precession CEST Sequence with Short Saturation at 3T Human Scanner |
| Chuyu Liu1, Yifan Li1, Zhongsen Li1, and Xiaolei Song1 | ||
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China |
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Keywords: CEST & MT, CEST & MT In this study, we proposed a steady state free precession CEST sequence with short saturation at 3T scanner. Our contributions are: 1) We investigated the SSFP process containing chemical saturation pulses and gave an approximate analytic solution. 2) Simulation and phantom results revealed that the proposed SSFP-CEST sequence had higher SNR and higher saturation efficiency than previous steady-state CEST, while the acquisition time was relatively short. |
| 3166 | Computer 111
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SNR-boosted whole-brain chemical exchange saturation transfer imaging by optimized variable flip angles |
| Xingwang Yong1, Yi-Cheng Hsu2, Yi Sun2, and Yi Zhang1 | ||
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China, 2MR Collaboration, Siemens Healthcare Ltd., Shanghai, China |
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Keywords: CEST & MT, CEST & MT It is well-known that the refocusing flip angles (FAs) of the SPACE sequence can be optimized to generate different image contrasts, such as T1-weighted or T2-weighted. However, the existing SPACE variable FA scheme is unsuitable for CEST imaging whose utmost aim is to increase the SNR during signal readout instead of enforcing contrast. Here, we derived a model to describe the signal-to-noise ratio (SNR) of the SPACE sequence, and maximized SNR by varying refocusing flip angles. Compared to the original constant FA protocol, the optimized variable flip angles yielded both SNR and resolution improvement. |
| 3167 | Computer 112
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Can pH can be a marker of hypoxia? Role of MRI CEST pH imaging in differentiating hypoxic from non-hypoxic tumors. |
| Aruna Singh1,2, Julia Stabinska1,2, Balaji Krishnamachary1, Kuldeep Gupta1, Farzad Sedaghat3, Sridhar Nimmagadda1, Jeff W. M. Bulte1, Zaver M. Bhujwalla1, and Michael T. Mcmahon1,2 | ||
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT, CEST MRI, hypoxia, acidosis, pH, Iopamidol, breast cancer, HIF-1 alpha Acidosis and hypoxia play a key role in developing metastasis and chemoresistance in tumors. pH measurement can be used as indicator of hypoxia and can provide insights into the metastatic potential of tumors. This study have explored chemical exchange-dependent saturation transfer (CEST) MRI based pH imaging to differentiate between two types of breast tumor models differing in their Hypoxia Inducible Factor-1α (mediator for hypoxia related adaptations in tumors) expression. Tumor acidification was observed in both with lower average extracellular pH (pHe = 6.1) in tumors with intact HIF-1α expression compared to those with HIF-1α silenced group (pHe = 6.2). |
| 3168 | Computer 113
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Metabolite detection in plants: A new application field for CEST? |
| Simon Mayer1,2, Fabian Tobias Gutjahr1, Ljudmilla Borisjuk2, and Peter Michael Jakob1 | ||
1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Germany, 2Leibniz-Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany |
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Keywords: CEST & MT, Metabolism, Technology transfer Chemical shift imaging (CSI) is rather challenging for the in vivo detection of low concentrated metabolites in plants due to its intrinsic low detection sensitivity and the need for accurate water suppression in the presence of magnetically inhomogeneous plant structures. As an alternative solution, we propose Chemical Exchange Saturation Transfer (CEST) for spectroscopic imaging. Within the work, several plant models were identified where CEST can be used as a versatile alternative for the detection of sugar and amino acids with increased spatial resolution and sensitivity, which demonstrates that CEST has a high potential for plant examinations. |
| 3169 | Computer 114
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No denoising, no diamonds? - In silico analysis of denoising methods for CEST MR imaging |
| Karl Ludger Radke1, Vibhu Adriaenssens1, Benedikt Kamp1, Patrik Jan Gallinnis1, Eric Bechler1, Hans-Jörg Wittsack1, Gerald Antoch1, and Anja Müller-Lutz1 | ||
1University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany, Düsseldorf, Germany |
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Keywords: CEST & MT, In Silico CEST imaging requires a high SNR to detect low metabolite concentrations, especially at clinical used magnetic field strength (3 Tesla). In recent years, various approaches have been used to denoise CEST data. Our study investigated the performance of different denoising algorithms using 1000 synthetic CEST MR data. Our results showed that PCA produced the best denoising results for CEST MR imaging in a simulation study. |
| 3170 | Computer 115
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Early-stage mapping of macromolecular tissue content in the brain of APPNL-F mouse model using nuclear Overhauser enhanced (NOE) MRI |
| Anshuman Swain1, Narayan Datt Soni2, Neil Wilson2, Halvor Juul2, Blake Benyard1, Dushyant Kumar2, Ravi Prakash Reddy Nanga2, Mohammad Haris2, and Ravinder Reddy2 | ||
1Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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Keywords: CEST & MT, Alzheimer's Disease This study utilizes nuclear Overhauser effect (NOE) MRI to map early-stage changes in macromolecular brain content of an APPNL-F model of Alzheimer's disease. NOEMTR and rNOE are the quantitative metrics used to assess lipids and proteins in major regions of the mouse brain. Following ROI analysis, there is a statistically significant decrease in NOEMTR contrast between wild-type and AD mice in the hippocampus, with rNOE showing a similar trend with a strong suggestion of statistical significance. Overall, this study shows that NOE MRI can be used to successfully detect changes in the macromolecular content of mouse brain tissue through NOEMTR. |
| 3171 | Computer 116
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Probing metabolites in antiretroviral and nicotine treated mouse brains using MRS and CEST-MRI |
| Gabriel Gauthier1, Aditya Bade1, and Yutong Liu1 | ||
1University of Nebraska Medical Center, Omaha, NE, United States |
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Keywords: CEST & MT, CEST & MT, MRI, MRS, HIV, Antiretroviral, nicotine, glutamate, myo-inositol, choline To better understand synergistic effects of antiretroviral drugs (ARV) and nicotine on neuroimmune functions, we observed drug-associated metabolites in mice utilizing CEST MRI and MRS. Increased CEST signal was found at 3.5 ppm suggesting increased glutamate in mice treated with nicotine. MRS results showed increased myo-inositol in both ARV and nicotine treated mice. glutamate is an excitatory neurotransmitter and myo-inositol is a biomarker of glial activation. The imaging results suggested elevated neuronal activation and neuroimmune dysfunction. |
| 3172 | Computer 117
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Using a deep residual learning framework to enhance APT-weighted (APTw) MR images of brain tumors acquired by SENSE with compressed sensing |
| Jingpu Wu1,2, Yiqing Shen1,3, Pengfei Guo1,3, Qianqi Huang3, Babak Moghadas1, Hye-Young Heo1, Jinyuan Zhou1, and Shanshan Jiang1 | ||
1Department of Radiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States, 2Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States, 3Department of Computer Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT Sensitivity encoding (SENSE) is often adopted to accelerate image acquisition for various MRI sequences, including APTw. This is further accelerated with SENSE with compressed sensing (called CS-SENSE), but the image quality degrades to some extent. We collected both SENSE- and CS-SENSE-APTw images and trained a generative model with residual learning to generate SENSE images from CS-SENSE images. The generated results were proved to be highly similar to SENSE-APTw images and less noisy than both SENSE- and CS-SENSE-APTw images. With a larger dataset, we can train more robust models and eventually replace SENSE- with CS-SENSE for a speedup of ~50%. |
| 3173 | Computer 118
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Simulation of a dynamic saturation CEST technique using MR fingerprinting for quantitative amide proton transfer imaging at 3 T |
| Jason Ostenson1,2 and Zhongliang Zu1,2 | ||
1Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States |
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Keywords: CEST & MT, MR Fingerprinting Conventionally, quantitative CEST imaging requires steady-state acquisitions so that the obtained signals can be fitted to simple analytical models, which takes a long scan time. Recently, transient-state techniques such as MR fingerprinting were developed to shorten the scan time. This study evaluates the potential of using a new pulse-by-pulse modulation of the saturation power acquisition in conjunction with an MRF reconstruction and fitting approach, termed dynamic saturation CEST, for quantitative APT imaging. Based on signal simulations, sensitivity analysis, and image simulations, we find it is plausible to estimate amide and macromolecular pool concentration, as well as water R1. |
| 3174 | Computer 119
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Characterization and Optimization of New CEST Reporter Proteins with Increased Detection Specificity |
| David E. Korenchan1, Adam Fillion2, Leo L. Cheng3, Assaf A. Gilad2, and Christian T. Farrar1 | ||
1Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, United States, 3Department of Pathology, Massachusetts General Hospital, Charlestown, MA, United States |
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Keywords: CEST & MT, Cell Tracking & Reporter Genes CEST reporter genes could play a critical role in the optimization of novel biological therapeutics. However, existing amide proton based CEST reporter genes have poor specificity as the amide protons of the reporter gene have the same chemical shift as amide protons from endogenous proteins. Here we report on a new class of reporter proteins with CEST contrast at 5-ppm, based on tyrosine hydroxyl ring protons. |
| 3175 | Computer 120
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Novel contrast agents for MR based on chemical exchange saturation transfer and its potential applications |
| Yanlong Jia1, Feng Wu1, Lin Yang2, Beibei Chen2, Yazhi Zhong3, Renhua Wu2, and Feng Li1 | ||
1Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, China, 2Department of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou, China, 3Department of Radiology, Huizhou central people's hospital, Huizhou, China |
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Keywords: CEST & MT, Molecular Imaging This study aimed to investigate some small molecular compounds with an appropriate chemical exchange site that can be employed as negative contrast agents for magnetic resonance imaging. 17 kinds of small molecular substances were selected and the imaging were performed on 7.0T MR system. Except for biotin, a series of small molecular substances have the characteristics of CEST. Salicylic acid (9.3ppm), 5-aminosalicylic acid (8.0ppm), and olsalazinesodium (9.8ppm) have large frequency offset, with optimal pH value 6.4～6.8, which are ideal candidates for CEST contrast agents. Due to the differences of molecular structure, the CEST characteristics were different. |
| 3272 | Computer 41
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Extending inhomogeneous MT to assess both neuromelanin and myelin in brainstem structures |
| Gopal Varma1, Jane Fergusson2, Asma Hassani2, Aaron K Grant1, Aron S Buchman3, David C Alsop1, and Veronique VanderHorst2 | ||
1Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 3Department of Neurological Sciences, Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL, United States |
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Keywords: Magnetization transfer, Neuro, Brainstem Application of neuromelanin MRI (NM-MRI) in the brainstem has been utilized in studies of neurological disorders such as Parkinson's disease. Acquisition of two types of MT preparation for inhomogeneous MT, MT applied at a single offset and then dual off-resonance frequencies, presents an advancement to NM-MRI by providing an acquisition with a myelin sensitive signal for complementary information. We demonstrate this in ex-vivo brainstem samples at 9.4 T, which allows comparison with other MRI microstructural techniques, as well as in-vivo at 3 T, where MT images provide a contrast comparable to NM-MRI by fast-spin-echo. |
| 3273 | Computer 42
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Quantitative Magnetisation Transfer Imaging using bSSFP to assess diffuse myocardial fibrosis. |
| Luke Pleva1, John Farrant1,2, Christopher Miller1,2, and Josephine Naish1,2 | ||
1The University of Manchester, Manchester, United Kingdom, 2MCMR, Manchester University NHS Foundation Trust, Manchester, United Kingdom |
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Keywords: Magnetization transfer, Cardiovascular Patients with chronic kidney disease often suffer from cardiac complications where increased diffuse myocardial fibrosis is present. Gadolinium is contraindicated in these patients, so cannot benefit from techniques such as ECV. We present a bSSFP based quantitative magnetisation transfer technique to assess diffuse myocardial fibrosis through the calculation of a pool size ratio and compare against ECV. 6 bSSFP images, T1, and T2 maps were acquired where a two pool model was fitted. No significant correlation between PSR and T1 in healthy patients was found. Significant correlations were found between PSR and T1 and PSR and ECV in clinical patients. |
| 3274 | Computer 43
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Characterization of semisolid proton $$$R_2$$$ orientation dependence in WM |
| Yuxi Pang1 | ||
1University of Michigan, Ann Arbor, MI, United States |
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Keywords: Relaxometry, White Matter Quantitative magnetization transfer (qMT) imaging can indirectly probe $$$R_2$$$ orientation dependence in WM for semisolid methylene protons from lipid bilayers. Prior experimental and simulation studies indicate that the long lipid chain not only rotates rapidly around itself, but it also wobbles in a cone. The existing modeling methods, however, did not take the latter motional mode into account, potentially leading to a biased measure of myelin-specific anisotropic $$$R_2$$$ relaxation. This work thus proposes a new model encompassing both motional modes for better characterizing an anisotropic $$$R_2$$$ profile of semisolid protons in WM. |
| 3275 | Computer 44
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Adiabatic Null Passage for on resonance magnetization transfer preparation |
| Shahrokh Abbasi-Rad1,2,3,4 and David Norris1,2 | ||
1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 3Department of Radiology, Harvard Medical School, Boston, MA, United States, 4Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlsetown, MA, United States |
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Keywords: Magnetization transfer, RF Pulse Design & Fields, Adiabatic Null Passage On-resonance bound pool saturation is the most efficient way of generating MTC. However, it suffers from excessive direct free water saturation due to RF pulse instabilities, and potential T2-weighting. We proposed a time-reversed adiabatic pulse (adiabatic null passage) for on-resonance MT preparation, by reversing the time-domain phase modulation function of a symmetric adiabatic pulse at its mid-point. We compared the MTC performance of ANP with binomial pulses using their MTR images. MTR values were reported through lines crossing CSF, showing high values at GM/WM and zero at CSF voxels. ANP improved the excessive saturation at regions with high B0 inhomogeneity. |
| 3276 | Computer 45
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Imaging magnetization exchange between cerebrospinal fluid and brain parenchyma in humans at 3 T |
| Jiaen Liu1 | ||
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States |
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Keywords: Magnetization transfer, Neurofluids Imaging mass exchange between cerebrospinal fluid (CSF) and brain parenchyma tissue is promising for enhancing our understanding about the role of CSF in clearance of metabolic waste and contributes to clinical diagnosis of neurological disorders and degeneration. In this study, we evaluated the feasibility of achieving this goal based on the magnetization transfer effect and CSF-selective spin echo contrast at 3 T in human subjects. The results suggested that techniques with low sensitivity to flow and partial volume effect are required for robust clinical application. |
| 3277 | Computer 46
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Saturation Transfer MR Fingerprinting (ST-MRF): free bulk water, semisolid macromolecule, and amide proton parameter quantification |
| Munendra Singh1, Peter van Zijl1, Shanshan Jiang1, Jinyuan Zhou1, and Hye-Young Heo1 | ||
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT Conventional saturation transfer MRI approaches, such as magnetization transfer contrast (MTC) and chemical exchange saturation transfer (CEST) MRI, acquire qualitative contrast weighted images, without specific information on the quantitative parameters affecting contrast, namely proton exchange rate and concentration. In addition, the contrast weighted images are highly dependent on scan parameters and data acquisition strategies. Here, we developed a fast, quantitative saturation transfer (ST) imaging technique based on MR fingerprinting principles to simultaneously estimate free bulk water, semisolid macromolecule, and amide proton-related parameters. The approach was evaluated with Bloch simulation and synthetic MRI analysis using in vivo human brains. |
| 3278 | Computer 47
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Asymmetric magnetization transfer ratio of locus coeruleus with sleep disorder: A 7T MRI study |
| Wenwen Yu1, Ying-Hua Chu2, Changyong Xie3, Shuanghong Chen3, Jianping Zhang3, Zidong Yang1, He Wang1,4, and Yuchuan Qiao1,4 | ||
1Institute of Science and Technology for Brain-inspired Intelligence,Fudan university, Shanghai, China, 2MR Collaboration, Siemens Healthineers Ltd., Shanghai, China, 3Center of Naval Special Medicine, Naval Medical University, Shanghai, China, 4Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China |
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Keywords: CEST & MT, Magnetization transfer, locus coeruleus, magnetization transfer ratio, neuromelanin sensitive MRI Neuromelanin (NM), mainly found in locus coeruleus (LC), is a well-known biomarker for neurodegenerative diseases such as Parkinson's disease (PD) and can be detected with neuromelanin-sensitive MRI (NM-MRI). However, whether NM content is associated with sleep disorders is largely unclear. We acquired 3D turbo flash MTC images from 20 normal and four dyssomnia adult males in a 7T scanner to examine the relationship between the sleep quality scores and the NM content in LC. Our preliminary results reveal that the magnetization transfer ratio (MTR), an indicator of NM concentration, of bilateral LC is significantly asymmetric in the dyssomnia group, and the mean value of MTR is lower in the left LC and higher in the right LC in dyssomnia group than normal group. |
| 3279 | Computer 48
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Simultaneous Neuromelanin Sensitive Imaging and Quantitative Susceptibility Mapping by 3D Multi-echo GRE sequence with Optimized MTC Pulse |
| Mengying Chen1, Yupeng Wu1, Qifan Pang1, Haodong Zhong1, Gaiying Li1, Yang Song2, Yi Wang3, and Jianqi Li1 | ||
1Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 2MR Scientific Marketing, Siemens Healthineers, Shanghai, China, 3Department of Radiology, Weill Medical College of Cornell University, New York, NY, United States |
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Keywords: CEST & MT, Magnetization transfer, Neuromelanin Although 3D magnetization transfer contrast (MTC) GRE sequence can image neuromelanin and magnetic susceptibility simultaneously, MTC saturation pulse takes too long time, and whether MTC affects accuracy of the susceptibility is unclear. Six subjects were scanned using 3D multi-echo GRE sequences with different durations of MTC pulse. 3D GRE sequence with 5ms of MTC pulse provided same saturation effects in highlighting neuromelanin as 10ms of MTC pulse, and yielded susceptibility values in the deep gray matter nuclei similar to sequence without MTC pulse. Short MTC pulse provides a practical means to simultaneously image the neuromelanin and magnetic susceptibility. |
| 3280 | Computer 49
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Model-based technique for rapid magnetization transfer corrected T1 mapping |
| Zhitao Li1, Johe Pauly2, and Shreyas Vasanawala1 | ||
1Department of Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States |
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Keywords: CEST & MT, Brain, T1 A model-based technique for rapid magnetization transfer corrected T1 mapping is proposed, the T1 maps generated from the proposed technique is free of the under-estimation caused by MT effect. The technique is validated in both simulation and in-vivo experiments. |
| 3281 | Computer 50
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Sequence optimization for saturation transfer MR fingerprinting |
| Munendra Singh1 and Hye-Young Heo1 | ||
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: CEST & MT, CEST & MT An optimal saturation transfer MR fingerprinting (ST-MRF) acquisition schedule is critical for efficient and accurate tissue parameter mapping. To optimize RF saturation-encoded MRF acquisitions to a minimal number of saturation scan parameters for magnetization transfer contrast (MTC) and chemical exchange saturation transfer (CEST) parameter determination, we developed an optimization framework using a support vector regression-recursive feature elimination (SVR-RFE) method. Bloch simulations and in vivo studies showed that the proposed optimization method outperformed the quantification accuracy compared to existing methods. The SVR-RFE-based optimization method allowed us to reduce scan time by ~50% without sacrificing reconstruction accuracy. |
| 3282 | Computer 51
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MT and CEST MRI of in vitro gastric protein digestion |
| Morwarid Mayar1,2, Mart de Vries1, Paul Smeets2,3, John van Duynhoven1, and Camilla Terenzi1 | ||
1Laboratory of Biophysics, Wageningen University & Research, Wageningen, Netherlands, 2Human Nutrition and Health, Wageningen University & Research, Wageningen, Netherlands, 3Image Sciences Institute, University Medical Centre Utrecht, Utrecht, Netherlands |
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Keywords: CEST & MT, Body, in vitro Gastric digestion of dietary protein is commonly studied using in vitro digestion models, which need to be verified with in vivo data. Here, we used MT and CEST MRI to monitor in vitro gastric digestion of milk proteins. We show that MT and CEST measurements can be used to monitor the breakdown of the initially-formed semi-solid protein coagulum and hydrolysis of soluble proteins. We also demonstrate that RF-based ratiometric CEST analysis can be used for pH mapping in both acid- and base-catalyzed regions. Our results open the way to quantification of in vivo protein digestion with the use of MRI. |
| 3283 | Computer 52
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The Influences on Amide Proton Transfer (APT) Signal Metrics at 3T: A Simulation and In-Vitro Study |
| Aisling Fothergill1, David Higgins2, Owen Thomas3, David Coope4, Ibrahim Djoukhadar3, and Laura Parkes1 | ||
1Geoffrey Jefferson Brain Research Centre, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom, 2Philips, Farnborough, United Kingdom, 3Department of Radiology, Geoffrey Jefferson Brain Research Centre, Salford Royal Hospital, Northern Care Alliance NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom, 4Department of Academic Neurological Surgery, Geoffrey Jefferson Brain Research Centre, Salford Royal Hospital, Northern Care Alliance NHS Foundation Trust, Manchester, United Kingdom |
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Keywords: CEST & MT, Quantitative Imaging, APT Amide Proton Transfer MRI shows clinical benefit in glioma imaging. Clinically useful APTw metrics should be sensitive to changes in amide concentration, a potential marker of tumour proliferation, and insensitive to T1 changes. To investigate sensitivity, simulations and in-vitro studies were performed over a range of amide concentrations and T1 values. In-vitro data included two varied concentration series, with and without T1-maintenance, and a constant concentration T1-vaired series. In-vitro results showed APT* had poor sensitivity, MTRrex was most sensitive to concentration and T1, AREX may overcorrect for T1, and MTRasym appears least sensitive to T1 while remaining sensitive to concentration. |
| 3284 | Computer 53
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A CEST Z-spectral learning network from 3T to higher B0 field: a simulation-based preliminary study |
| Mengdi Yan1, Chongxue Bie1, Yibin Chen1, Xiaowei He1, and Xiaolei Song2 | ||
1Northwest University, Xi'an, Shanxi, China, 2Tsinghua University, Beijing, China |
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Keywords: CEST & MT, Data Analysis Z-spectrum acquired under ultra-high field (> 3T) features stronger and better isolated CEST peaks than those under 3T. But from imaging aspect, 3T scanners perform better and are clinically accessible. Herein, we built a deep neural network (DNN) for predicting Z-spectrum under higher B0 from the corresponding measurement at 3T. The network was trained by 10 million Z-spectra calculated from Bloch-equation models. Simulations with various B0 shifts and noise suggested that 3T Z-spectra could be rapidly and accurately transformed to those under 7T or 9.4T. This network may help improve signal extraction and interpretation of CEST data acquired at 3T. |
| 3285 | Computer 54
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Optimization and validation of Creatine- and Glutamate-CEST weighted imaging in the human brain at 7T |
| Bárbara Schmitz-Abecassis1,2, Chloé Najac1, Jaimy Plugge1, Matthias J.P. van Osch1,2, and Ece Ercan1,3 | ||
1Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Medical Delta Cancer Diagnostics 3.0, South-Holland, Netherlands, 3Philips Healthcare, Best, Netherlands |
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Keywords: CEST & MT, High-Field MRI Amine chemical exchange saturation transfer (CEST) is highly sensitive for imaging metabolites in vivo. However, it lacks specificity. We aimed to develop and validate optimal CEST protocols to image creatine and glutamate in the human brain at 7T. Simulations were used to define optimal acquisition parameters, followed by in vitro validation. The optimal B1rms and total saturation (tsat) parameters were determined for creatine (B1rms = 2.5μT & tsat = 1500ms) and glutamate (B1rms = 3.5μT & tsat = 1000ms). These protocols were then used in healthy volunteers to investigate the correlation of glutamate- and creatine-weighted CEST with magnetic resonance spectroscopy results. |
| 3286 | Computer 55
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Demonstration of B1 mapping based RF shimming for CEST imaging at 7T |
| Eleni Demetriou1,2, Ivan E Dimitrov1,3, Peter van Zijl4,5, Hans Hoogduin6, Elena Vinogradov7, Bei Zhang8, and Anke Henning8 | ||
1Advanced imaging research center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Brain repair and Rehabilitation, UCL, London, United Kingdom, 3Philips healthcare, Florida, FL, United States, 4F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, United Kingdom, 5Department of Radiology, Johns Hopkins University, Baltimore, MD, United States, 6Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands, Ultrecht, Netherlands, 7Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 8Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States |
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Keywords: CEST & MT, Brain, B1 inhomogeneities In this work, we sought to evaluate CEST in combination with RF shimming that is based on the modulation of the amplitudes and phases of the RF pulses transmitted by an eight channel 7T MR system. |
| 3287 | Computer 56
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Bloch-McConnell Simulation for Arterial Blood Contrast at 3T and 7T: Adiabatic Null Passage vs Binomial Magnetization Transfer Preparation |
| Shahrokh Abbasi-Rad1,2,3,4 and David Norris1,2 | ||
1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 3Department of Radiology, Harvard Medical School, Boston, MA, United States, 4Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States |
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Keywords: fMRI, Magnetization transfer, Arterial Blood Contrast Arterial blood contrast (ABC) uses on-resonance binomial pulse for magnetization transfer preparation to saturate the tissue signal and highlights the contribution of arterioles. Previously, using Bloch-McConnel simulations, we showed that Binomial MT contaminates ABC with T2 contrast. We suggested the use of adiabatic null passage to decrease the T2 effect. We performed Bloch-McConnel simulations at 3T and 7T comparing the performance of binomial and ANP pulses. ANP increased the arterial contribution from 32% to 42% at 3T and from 18% to 30% at 7T. This study concludes that ANP reduces the T2-contamination imposed by binomial MT block and improves ABC. |
| 3288 | Computer 57
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HyperCEST Potential of Members of the Cucurbit[n]uril Family: Revised Signal Assignment and Suitable Host Identification with Accelerated MRI |
| Leif Schröder1, Hen Amit Morik1, and Patrick Schuenke2 | ||
1Translational Molecular Imaging, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany, 2Biomedical Magnetic Resonance, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany |
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Keywords: Contrast Agent, CEST & MT The full potential of the ultra-sensitive approach of HyperCEST MRI crucially depends on host structures with efficient release of hyperpolarized 129Xe. Cucurbit[n]urils (CB6 and CB7) have been proposed as promising candidates but a quantitative analysis of CEST signatures yet remained an open question. Here, we use MRI-derived z-spectra of multiple samples which provide strong evidence that CB7 is unsuitable as CEST agent and that previously observed signals are solely assigned to CB6 which is also side product in CB7 synthesis. Image acquisition with >20-fold acceleration for the 4-dimensional datasets is possible without compromising a detailed quantitative analysis. |
| 3289 | Computer 58
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Maximization of cucurbit[6]uril hyperpolarized chemical exchange saturation transfer (HyperCEST) in bovine blood at 3.0 T |
| Vira Grynko1,2, Viktoriia Batarchuk2,3, Yurii Shepelytskyi2,3, Hannah Aalto4, Joseph Deschamps4, Iulian Constantin Russet5, and Mitchell Albert2,3,6 | ||
1Chemistry and Materials Science Program, Lakehead University, Thunder Bay, ON, Canada, 2Thunder Bay Regional Health Research Institute, Thunder Bay, ON, Canada, 3Chemistry, Lakehead University, Thunder Bay, ON, Canada, 4Applied Life Science Program, Lakehead University, Thunder Bay, ON, Canada, 5Xemed LCC, Durham, NH, United States, 6Northern Ontario School of Medicine, Thunder Bay, ON, Canada |
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Keywords: Hyperpolarized MR (Gas), Contrast Agent Cucurbit[6]uril is a well-studied contrast agent for hyperpolarized 129Xe (HP 129Xe) MRI. Although the in vivobiodistribution of CB6 was measured with hyperpolarized chemical exchange saturation transfer (HyperCEST), there were no previous studies reported for maximization of the HyperCEST effect by optimization of depolarization pre-pulse trains. In the present work, we maximized the CB6 HyperCEST effect in bovine blood, and found for the first time, a HyperCEST depletion of the RBC resonance. In addition, the minimum detectable concentration was found to be four times lower than previously reported. |
| 3290 | Computer 59
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Amide Proton Transfer-Weighted MRI in Preoperative Assessment of Microvascular Invasion of Hepatocellular Carcinoma: A Preliminary Study |
| Jingcheng Huang1, Chengshi Hou1, Qingqing Wen2, Weiqiang Dou2, and Xianfu Luo1 | ||
1Clinical Medical School of Yangzhou University, Northern Jiangsu People’s Hospital, Yangzhou, China, Yangzhou City, China, 2GE Healthcare, MR Research China, Beijing, P.R. China, Beijing City, China |
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Keywords: Quantitative Imaging, CEST & MT, APTw Conventional MRI methods are difficult to reveal histologic and molecular characteristic of HCC. In this study, we aimed to e explore the feasibility of amide proton transfer weighted (APTw) imaging for predicting microvascular invasion (MVI) of hepatocellular carcinoma. Significant difference in APTw values were observed for MVI positive and negative lesions. With these findings, APTw imaging can be considered a potential technique for noninvasive preoperational assessment of MVI in hepatocellular carcinoma. |
| 3663 | Computer 81
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Measuring individual vein and artery BOLD responses to visual stimuli in humans with multi-echo single-vessel functional MRI at 7T |
| Divya Varadarajan1,2, Paul Wighton1,2, Jingyuan Chen1,2, Sebastien Proulx1,2, Robert Frost1,2, Andre van der Kouwe1,2, Avery Berman3, and Jonathan R. Polimeni1,2 | ||
1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Carleton University, Ottawa, ON, Canada |
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Keywords: fMRI, Blood vessels Here we apply single-vessel fMRI techniques to evaluate BOLD and non-BOLD contributions within individual arteries and veins. First we identified individual vessels from inflow effects in a small set of slices, and distinguished arteries and veins on the basis of their T2* decay. Then we applied a high-inplane-resolution multi-echo single-vessel fMRI approach to examine fMRI responses within these vessels. We find evidence for both BOLD and potentially non-BOLD responses within arteries, suggesting that in some cases BOLD may capture arterial responses BOLD which may be more neuronally specific (in space and time) than effects from downstream veins. |
| 3664 | Computer 82
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Ocular Dominance Columns Examined using BOLD fMRI with Phase Regression at 7 T |
| Brett Liem1,2, Atena Akbari1,2, Joseph S Gati1, Peter Zeman1, and Ravi S Menon1,2 | ||
1Centre for Functional and Metabolic Mapping, Robarts Research Institute, London, ON, Canada, 2Medical Biophysics, The University of Western Ontario, London, ON, Canada |
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Keywords: fMRI (task based), High-Field MRI, Phase Regression We investigated the signal spatial specificity of the GRE-BOLD contrast with and without phase regression in ocular dominance columns and layers of human V1. Phase regression is a post-processing technique that uses phase data to suppress the large vein signal, thus improving the GRE signal spatial specificity. Our results showed that the phase regressed laminar BOLD signal profile peaks towards the middle cortical depth, while that of GRE-BOLD was biased towards the cortical surface. Phase regression did not improve the contrast between columns, suggesting that the phase is not sensitive to intracortical veins running parallel to the cortical surface. |
| 3665 | Computer 83
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Dependence of the EPI and bSSFP resting-state fMRI signals on the cortical orientation relative to B0: Initial observations at 9.4 Tesla |
| Dana Ramadan1,2, Jonas Bause1, Rüdiger Stirnberg3, Philipp Ehses3, and Klaus Scheffler1,4 | ||
1Department for High-field Magnetic Resonance, Max Planck Institute for Biological Cybernetics Tübingen, Tübingen, Germany, 2Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany, 3German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, 4Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany |
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Keywords: fMRI, High-Field MRI, Blood Vessels, Brain The spatial specificity of fMRI with GRE-EPI is significantly affected by large draining veins on the cortical surface. They cause susceptibility changes that are strongest when the veins are oriented perpendicular to B0. Since they follow the cortical curvature, their orientation to B0 can be approximated by the cortical orientation. Previous studies have shown a high dependence of the GRE-EPI signal on the cortical orientation, reflecting its disadvantage of being sensitive to these veins. In this preliminary two-subject study, this phenomenon is investigated with GRE-EPI and bSSFP in different cortical depths to experimentally explore the sensitivity of bSSFP to microvasculature. |
| 3666 | Computer 84
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Application of SLR pulses to short-TR spin-echo fMRI at 7T: SNR considerations and a direct demonstration of reduced cardiac noise |
| Mukund Balasubramanian1,2, Avery J. L. Berman3,4, Robert V. Mulkern1,2, Lawrence L. Wald1,5, William A. Grissom6, and Jonathan R. Polimeni1,5,7 | ||
1Harvard Medical School, Boston, MA, United States, 2Boston Children's Hospital, Boston, MA, United States, 3Carleton University, Ottawa, ON, Canada, 4University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada, 5Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 6Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 7Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Keywords: fMRI, RF Pulse Design & Fields, Ultra-High-Field MRI We show that SLR pulses provide much better slice profiles (and thus much higher SNR) than standard sinc pulses for short-TR spin-echo (SE) acquisitions, even when there is substantial B1+ inhomogeneity. As one application, we used SLR pulses and a TR of 300 ms in SE-EPI acquisitions at 7T, enabling the “direct” measurement of cardiac frequencies at ~1 Hz without aliasing. Far less cardiac fluctuation was seen in SE- versus GE-EPI data. While SE-fMRI is known to have reduced macrovascular weighting and thus improved spatial specificity relative to GE-fMRI, our results suggest that it may also have better temporal specificity. |
| 3667 | Computer 85
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Mapping stimulus-driven hemodynamic changes in white matter using 7T high-resolution fMRI |
| Jiawen Dakota Fan1,2, Javier Gonzalez-Castillo3, Peter A. Bandettini3,4, Jonathan R. Polimeni2,5,6, and Jingyuan E. Chen2,5 | ||
1Center for Data Science, New York University, New York City, NY, United States, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 3Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Health, Bethesda, MD, United States, 4Functional MRI Core, National Institute of Health, Bethesda, MD, United States, 5Department of Radiology, Harvard Medical School, Boston, MA, United States, 6Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Keywords: fMRI, White Matter In this study, by integrating 7T high-resolution imaging and massive data averaging, we show that white matter fMRI activations can be detected at a single-voxel level. Hemodynamic changes evoked by the flickering checkerboard stimuli were not homogenous within the optic radiation, and the averaged pattern exhibited a delayed time to peak longer than V1, consistent with previous literature. The current datasets also revealed stimulus-locked changes in certain white-matter tracts beyond the visual pathway. |
| 3668 | Computer 86
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Characterizing across-trial variation in the hemodynamic responses using ultra-fast fMRI data at 7T |
| Samuel Bianchi1, Jakob Heinzle2, Maria Engel1, Stefan Frässle2, Klaas Enno Stephan2,3, and Klaas Paul Pruessmann1 | ||
1Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland, 2Translational Neuromodeling Unit (TNU), Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland, 3Max Planck Institute for Metabolism Research, Cologne, Germany |
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Keywords: fMRI (task based), Modelling, Hemdoynamic response, HRF, Activation, BOLD Characterizing hemodynamic responses with great temporal precision is crucial for the interpretation of fMRI data with respect to the underlying neuronal activity. Recent literature highlights that analyses based on a canonical hemodynamic response function (HRF) may fail to capture relevant aspects of neuronal activity in certain conditions1. Ultra-fast fMRI enables precise temporally precise characterizations of hemodynamic responses and their trial-by-trial variation. Here, we analyzed fMRI timeseries sampled at which allowed us to model hemodynamic responses for individual trials during a visuo-motor task. Trial-by-trial variability of hemodynamic responses are analyzed by principal components analysis (PCA) and related to trial-specific conditions. |
| 3669 | Computer 87
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Combining the benefits of 3D acquisitions and spiral readouts for VASO fMRI at UHF |
| Alejandro Monreal-Madrigal1, Denizhan Kurban1, Zoia Laraib1,2, Renzo Huber1, Dimo Ivanov1, Nicolas Boulant3, and Benedikt A Poser1 | ||
1Maastricht University, Maastricht, Netherlands, 2Polytechnic University of Turin, Turin, Italy, 3University-Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France |
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Keywords: fMRI, High-Field MRI, Pulse Sequence Design VASO fMRI can provide beneficial localization specificity and quantifiability compared to the commonly used BOLD contrast. Previous work has also shown the benefits of using spiral readouts compared to Cartesian EPI. In this work, we employ 3D stack-of-spirals readouts and compare it with the current state of the art 3D EPI readouts for VASO fMRI. The sequence implementation is done using Pulseq, images were reconstructed with MRIReco.jl; functional analysis with an openly available pipeline. We find that a VASO tSNR improvement of a factor of 2 over EPI is achieved using the proposed spiral implementation. |
| 3670 | Computer 88
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Pushing limits of spatial resolution in 3D EPI for fMRI on the NexGen 7T scanner |
| Alexander JS Beckett1,2, Samantha J Ma3, An T Vu4,5, and David A Feinberg1,2 | ||
1Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States, 2Advanced MRI Technologies, Sebastopol, CA, United States, 3Siemens Medical Solutions USA, Inc., Malvern, PA, United States, 4Radiology, University of California, San Francisco, CA, United States, 5San Francisco Veteran Affairs Health Care System, San Francisco, CA, United States |
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Keywords: fMRI, Neuroscience Resolution in functional imaging can be increased by limiting the Field of View (FOV) for the image, increased acceleration and faster imaging using specialized gradient systems. Here we combine the high performance gradients of the NexGen 7T scanner with limited FOV imaging to collect ultra-high resolution fMRI in the occipital pole. Isotropic resolutions of 0.35mm are demonstrated using 3D EPI. |
| 3671 | Computer 89
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Entrainment between musical stimuli and cortical depth-dependent fMRI signals |
| Hsin-Ju Lee1,2, Hankyeol Lee3, Kamil Uludag4, and Fa-Hsuan Lin1,2 | ||
1Physical Sciences Platform, Sunnybrook Research institute, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of, 4Techna Institute & Koerner Scientist in MR Imaging, University Health Network, Toronto, ON, Canada |
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Keywords: fMRI (task based), fMRI (task based) We use cortical-depth dependent fMRI to study the correlation between neural oscillations and fMRI signals across cortical depths in the auditory cortex during music listening. The correlation between fMRI signals and acoustic stimuli was the strongest at the primary auditory cortex in the intermediate cortical depths during the first listening, matching the hypothesis of feedforward signal supported by the connectivity. The correlation was suppressed in the repeated listening, superficial as well as deep depths, and at the secondary auditory cortex. |
| 3672 | Computer 90
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Direct imaging of Neuronal Activity (DIANA) in Humans |
| Shota Hodono1, Reuben Rideaux2, Timo van Kerkoerle3, and Martijn A. Cloos1 | ||
1Centre for Advanced Imaging, University of Queensland, St Lucia, Australia, 2Queensland Brain Institute, University of Queensland, St Lucia, Australia, 3NeuroSpin, The French Alternative Energies and Atomic Energy Commission (CEA), Gif-Sur-Yvette, France |
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Keywords: fMRI, Contrast Mechanisms, DIANA Here we describe our initial results attempting to observe neuronal activation in humans using the Direct Imaging of Neuronal Activity (DIANA) method. Both visual and auditory paradigms were explored. BOLD and anatomical ROI were tested and dedicated single slice control experiments were performed, but clear DIANA signals remained elusive. The translation of DIANA from animals to humans appears to be non-trivial. Nevertheless, considering the potential payoff continued effort towards this goal may be well worth it. To aid in this quest, parallel studies focused on DIANA’s ability to detect spiking and hyperpolarisation in controlled settings may be of great value. |
| 3673 | Computer 91
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Using laminar fMRI and modeling to study auditory predictive processing |
| Lonike Faes1, Isma Zulfiqar1, Luca Vizioli2, Zidan Yu3, Yuan-Hao Wu4, Jiyun Shin4, Ryszard Auksztulewicz5, Lucia Melloni6,7, Kamil Uludag8, Essa Yacoub2, and Federico De Martino1,2 | ||
1Deparment of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands, 2Center for Magnetic Resonance Research, Minneapolis, MN, United States, 3University of Hawaii, Honolulu, HI, United States, 4New York University Grossman School of Medicine, New York University, New York, NY, United States, 5Center for Cognitive Neuroscience Berlin, Free University Berlin, Berlin, Germany, 6Department of Neurology, New York University, New York, NY, United States, 7Department of Neurophysiology, Max-Planck Institute for Brain Research, Frankfurt am Main, Germany, 8Joint Department of Medical Imaging and Krembil Brain Institute, Techna Institute & Koerner Scientist in MR Imaging, Toronto, ON, Canada |
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Keywords: fMRI (task based), High-Field MRI We use ultra-high field fMRI to explore the differential role of cortical layers in the information flow between top-down predictions and bottom up sensory evidence in a predictive coding (PC) framework. As the measured BOLD signal is affected by vascular draining, we use a computational model that combines neuronal dynamics with laminar vascular physiology to help us understand prediction signals at cortical depths and underlying neuronal responses. We show that a violation in prediction caused response modulation in superficial and deep layers in the primary auditory cortex, which is in line with the PC framework. |
| 3674 | Computer 92
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Increasing MT contrast in laminar fMRI using PUSH pTx pulses |
| Viktor Pfaffenrot1, David Leitao2,3, Annika Verheyen1, Markus May1,4, Raphael Tomi-Tricot5, Shaihan Malik2,6, and David Norris1,7 | ||
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany, 2Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 3London Collaborative Ultra high field System (LoCUS), London, United Kingdom, 4High Field and Hybrid MR Imaging, University Duisburg-Essen, University Hospital Essen, Essen, Germany, 5MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 6Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 7Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands |
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Keywords: fMRI, Magnetization transfer, laminar fMRI The GRE-BOLD contrast used in laminar fMRI suffers from suboptimal specificity due to unwanted extravascular effects. Recently, efforts were made to increase specificity of GRE-BOLD by means of CBV-weighting using the magnetization transfer contrast. The specificity improvement depends on the amount of selective GM signal reduction. We investigate whether PUSH pTx pulses, designed to maximize MT contrast in a given area, can achieve a higher functional contrast. Our results suggest that when opting for high-power, off-resonant MT pulses, both PUSH and a CP2+ mode perform equally well in increasing the functional contrast at short TE compared to GRE-BOLD in V1. |
| 3675 | Computer 93
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Separation of sensory and attention input to the human primary somatosensory cortex by spin- and gradient-echo BOLD fMRI |
| SoHyun Han1,2, Dongho Kim1,2, and Seong-Gi Kim1,2 | ||
1Center for Neuroscience Imaging Research, Suwon, Korea, Republic of, 2Sungkyunkwan University, Suwon, Korea, Republic of |
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Keywords: fMRI, Brain High spatial resolution laminar specific fMRI has a potential to separate between top-down and bottom-up signals. In this study, we investigated the effect of attention across cortical layers in the human S1 using SAGE-EPI sequence. fMRI experiments during vibrotactile stimulation with passive and attention tasks with 0.8mm isotropic resolution at 7T were performed. We demonstrated that the SE-BOLD can identify laminar profiles of bottom-up and top-down processes: the laminar profile of passive task showed the peak at layer 4, but that of attention task showed the peak at the superficial layers. |
| 3676 | Computer 94
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Isolating the arterial blood volume change to probe fMRI spatial specificity |
| Nikos Priovoulos1,2, Icaro Agenor Ferreira de Oliveira1,2,3, Benedikt Poser4, David G Norris5,6, and Wietske van der Zwaag1,2 | ||
1Spinoza Center for Neuroimaging, Amsterdam, Netherlands, 2Computational Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, Amsterdam, Netherlands, 3Techna Institute, University Health Network, Amsterdam, Netherlands, 4MR-Methods group, MBIC, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands, 5Donders Institute for Brain, Cognition and Behaviour, Donders Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Nijmegen, Netherlands, 6Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany |
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Keywords: fMRI, fMRI, high field, cerebral blood volume BOLD fMRI is widely used in neuroscience, but has limited spatial specificity while alternative approaches based on tissue cerebral blood volume (CBV) change have limited sensitivity. Recently, arterial CBV change (Arterial Blood Contrast; tracked through magnetization-transfer) was suggested as an fMRI mechanism, but its localization and sensitivity remain unexplored, since efficiently isolating the arterial CBV is challenging. Here, we combine temporally-efficient saturation with center-slice-out readouts and BOLD-correction to isolate arterial CBV for high-resolution 7T human fMRI. Our novel sequence shows much-improved specificity compared to BOLD and similar sensitivity to VASO, suggesting Arterial Blood Contrast to be a promising fMRI approach. |
| 3677 | Computer 95
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Potential of diffusion fMRI for detecting white matter activity in the human brain |
| Jasmine Khedidja Nguyen-Duc1, Wiktor Olszowy2, Jonathan Patino Lopez 3, and Ileana Jelescu1 | ||
1Department of Radiology, CHUV, Lausanne, Switzerland, 2CIBM Center for Biomedical Imaging, Lausanne, Switzerland, 3Signal Processing Lab (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland |
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Keywords: fMRI (task based), Diffusion/other diffusion imaging techniques, simulations, diffusion fMRI Diffusion functional Magnetic Resonance Imaging (dFMRI) may be used to study the white matter activation in a more direct way than BOLD. The aim of this work is to extract the decrease in apparent diffusion coefficient (ADC) in the white matter observed in real data, and compare to that in a simulation of realistic axon swelling. Results suggest that the decrease is of low amplitude (<0.5%) but nonetheless detectable. |
| 3678 | Computer 96
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Proprioceptive engagement in the human cerebellum using 7T-fMRI |
| Emma Brouwer 1,2, Julie Hashimoto 1,3, Nikos Priovoulos1,2, and Wietske van der Zwaag1,2 | ||
1Spinoza Centre for Neuroimaging, Amsterdam, Netherlands, 2Computational Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, Amsterdam, Netherlands, 3Vrije Universiteit Amsterdam, Amsterdam, Netherlands |
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Keywords: fMRI (task based), Brain, cerebellum The human cerebellum forms an important part of the sensory and motor networks. Specifically, cerebellar damage has been shown to result in difficulty to perform proprioceptive tasks. Hence, studying the functional cerebellar organisation can be of great neuroscientific and clinical interest. This requires high-resolution images due to the thin, highly-foliated cortex of the cerebellum. We investigated the difference between a simultaneous-unilateral-finger-flex (SUFF) and midline-contralateral-finger-touch (MCFT) using B1-shimmed fMRI at 7T. Movements with higher proprioceptive engagement (MCFT) resulted in stronger, more medially located activations on the cerebellar surface compared to movements which are less reliant on proprioception (SUFF). |
| 3679 | Computer 97
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Multi-echo EPI for improving temporal resolution in task-based fMRI at 7T- a dynamic phantom study |
| Guy Shlomo Baz1,2, Edna Furman-Haran 2,3, and Rita Shmidt1,2 | ||
1Department of brain sciences, Weizmann Institute, Rehovot, Israel, 2The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute, Rehovot, Israel, 3Life Sciences Core Facilities, Weizmann Institute, Rehovot, Israel |
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Keywords: fMRI (task based), High-Field MRI Ultra-high field MRI provides increased sensitivity, which we aim to utilize for improving the temporal resolution in functional studies. To investigate the achievable resolution at 7T MRI, a dynamic phantom that can generate an fMRI-like time-series was used. A dataset based on block-design with defined time shifts and a range of contrast-to-noise values was used to characterize the effective temporal resolution. Estimated temporal resolution was x1.7 times better for multi-echo compared to single-echo EPI, estimated as 146ms for a scan with TR of 600ms. This study offers a novel approach of optimizing protocols and new insights into fMRI temporal resolution. |
| 3680 | Computer 98
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Investigating the feasibility of functional MRI using GRE EPI on a high performance 0.5 T Scanner |
| Arjama Halder1, Chad T. Harris2, Curtis N. Wiens2, Andrew T. Curtis2, William B. Handler3, Andrea Soddu3, and Blaine A Chronik1,3 | ||
1Medical Biophysics, Western University, London, ON, Canada, 2Research and Development, Synaptive Medical, Toronto, ON, Canada, 3Physics and Astronomy, Western University, London, ON, Canada |
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Keywords: fMRI, fMRI (task based) fMRI is typically not performed at field strengths < 1.5T due to low magnetic susceptibility contrast and inadequate gradient performance. Leveraging the high-performance gradient set of a head-only 0.5T MRI, the feasibility of motor task based fMRI was evaluated using a 4mm isotropic GRE-EPI acquisition. Activated regions within the PMC were consistent with expected behaviour. Furthermore, a significant change in signal during activation of 1.8+/-0.4% was measured within an ROI of activated voxels. These results suggest that motor task based BOLD fMRI is possible at 0.5T. |
| 3681 | Computer 101
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High-Resolution J-Edited MRSI Using Multi-Slab Acquisition and Learned Subspaces |
| Rong Guo1,2, Yibo Zhao2,3, Yudu Li2,4, Chao Ma5, Wen Jin2,3, Yao Li6, Georges El Fakhri5, Brad Sutton2,3,4,7,8, and Zhi-Pei Liang2,3,4 | ||
1Siemens Medical Solutions USA, Inc., Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 4National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 5Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States, 6School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 7Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 8Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States |
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Keywords: Spectroscopy, Spectroscopy High-resolution mapping of GABA in the brain has long been desired by the neuroscience community. But it is still challenging due to several long-standing technical obstacles including low SNR, long scan time, and spectral overlapping. This work proposes an MRSI method integrating multi-slab EPSI acquisition, MEGA spectral editing, and subspace modeling to overcome these difficulties, successfully achieving 3D GABA and metabolite mapping (at 3.0×3.0×4.0 mm3 nominal resolution) in a 12-minute scan time. |
| 3682 | Computer 102
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Whole-Brain Multi-Parametric Molecular Imaging Using Accelerated J-Resolved Subspace 1H-MRSI |
| Zepeng Wang1,2, Yahang Li1,2, and Fan Lam1,2 | ||
1Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States, 2Beckman Institute for Advanced Science and Technology, Urbana, IL, United States |
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Keywords: Spectroscopy, Quantitative Imaging J-resolved MRSI is a powerful molecular imaging tool for measuring brain metabolites, neurotransmitters and other important biophysical parameters. The inherent SNR challenge of MRSI and prolonged scan time for multi-TE data limit the imaging resolution. This work presents a brand-new capability of whole-brain multiparametric, quantitative MRSI, by integrating a fast-scanning J-resolved MRSI sequence with SNR-efficient multi-band excitation, task-specific experiment designs, subspace imaging and optimized parameter estimation. Experimental studies and initial validation were performed to demonstrate this capability for high-resolution metabolite, neurotransmitter and metabolite T2 mapping from a single scan. |
| 3683 | Computer 103
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Selective Extraction of J-coupled Signals Using MEGA-PRESS with Conditional Saturation Pulses |
| Hidenori Takeshima1, Shuki Maruyama2, and Masao Yui3 | ||
1Imaging Modality Group, Advanced Technology Research Department, Research and Development Center, Canon Medical Systems Corporation, Kanagawa, Japan, 2Imaging Modality Group, Advanced Technology Research Department, Research and Development Center, Canon Medical Systems Corporation, Tochigi, Japan, 3Research and Development Center, Canon Medical Systems Corporation, Tochigi, Japan |
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Keywords: Pulse Sequence Design, Spectroscopy In this abstract, a spectral editing method using MEGA-PRESS with conditional frequency-selective saturation pulses is proposed. The proposed method used additional frequency-selective saturation blocks before the excitation block. The saturation pulses were activated only when the MEGA pulses were inactive. When saturation pulses were activated, the sequence acted as the conventional MEGA-PRESS whose editing pulses were inactive except that the passband of the saturation pulse was not excited. Spectrum reconstruction for the proposed method was same as that for the conventional MEGA-PRESS. Experimental results showed that the proposed method selectively extracted J-coupled signals with all frequencies. |
| 3684 | Computer 104
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Test-retest reliability of PRESS- and sLASER-localized multi-metabolite spectral editing |
| Mark Mikkelsen1, Ralph Noeske2, and Dikoma Shungu1 | ||
1Department of Radiology, Weill Cornell Medicine, New York, NY, United States, 2GE Healthcare, Berlin, Germany |
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Keywords: Spectroscopy, Spectroscopy, Reproducibility Multi-metabolite spectral-edited MRS enables the efficient detection of multiple low-concentration metabolites. Two such approaches, HERMES and HERCULES, directly edit two or more metabolites in a single scan. However, the reproducibility of these techniques has yet to be fully established. This study investigated PRESS- and sLASER-localized HERMES and HERCULES test-retest reliability, with the additional aim of demonstrating that sLASER localization is the better of the two sequences for obtaining reproducible measurements. Overall, the test-retest reliability of sLASER was found to be higher than that of PRESS. |
| 3685 | Computer 105
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Short-TE semi-LASER 1H MRS of the primary motor cortex in ALS and controls at 7 Tesla |
| Zeinab Eftekhari1,2,3, Thomas B Shaw1,4,5, Jin Jin2,6, Kieran O'Brien6, Gary Cowin1, Dinesh K Deelchand7, Robert Henderson5,8, Frederik Steyn5,8, Sicong Tu9, Wolfgang Bogner10, and Markus Barth1,2,4 | ||
1Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, 2ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, Brisbane, Australia, 3Queensland Brain Institute, The University of Queensland, Brisbane, Australia, 4School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, 5Neurology Department, Royal Brisbane and Women’s Hospital, Brisbane, Australia, 6Siemens Healthcare Pty Ltd, Brisbane, Australia, 7Centre for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 8School of Medicine, The University of Queensland, Brisbane, Australia, 9Brain and Mind Centre, The University of Sydney, Sydney, Australia, 10High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria |
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Keywords: Spectroscopy, Spectroscopy, High-Field MRI, Magnetic Resonance Spectroscopy Magnetic Resonance Spectroscopy (MRS) can offer a unique, non-invasive tool for measuring the neurochemicals in the brain in vivo. This technique may be useful for studying the ratio of metabolites in both health and disease, including in Amyotrophic Lateral Sclerosis (ALS), where differing neuronal populations of the motor cortex are impacted. This study aimed to develop a 7T MRS protocol for ALS patients and measured metabolite ratios in the upper and lower limb regions of the motor cortex at 7T in controls and in ALS. This has the potential to improve progression monitoring and diagnostic certainty in early-stage disease. |
| 3686 | Computer 106
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Optimizing MRSI semi-LASER for mouse brain tumor studies: evaluation of increased spatial resolution and k-space sampling strategies |
| Zoona Javed1,2, Gary V Martinez3, Marta Mulero-Acevedo1,4,5, Ana Paula Candiota1,4,5, Carles Arús 1,4,5, Miquel Cabañas Egaña2,4, and Silvia Lope-Piedrafita2,4 | ||
1Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain, 2Servei de Ressonància Magnètica Nuclear, Universitat Autonoma de Barcelona, Cerdanyola del Valles, Spain, 3Department of Imaging Physics,, The University of Texas M.D. Anderson Cancer Center, Houston, TX, United States, 4Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Valles, Spain, 5Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain |
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Keywords: Spectroscopy, Cancer, Brain Tumor MRSI-based nosological images have been previously applied to monitor therapy response in a murine model of GL261 glioblastoma using a commercially available MRSI-PRESS sequence. Due to the heterogeneous nature of glioblastomas, increasing spatial resolution could provide additional insight into changes related to therapy response. The in-house implementation of the MRSI-semi-LASER sequence, using weighted acquisition, has allowed us a 20% slice thickness reduction without losing relevant spectral quality. Moreover, different k-space sampling strategies have been evaluated showing significant SNR increase with elliptical sampling, which may allow further increase in the spatial resolution or reduction in the total experimental time. |
| 3687 | Computer 107
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Comparison of STEAM and sLASER to quantify acetylcarnitine at rest using long TE 1H-MRS in human skeletal muscle with a surface or birdcage coil at 7T |
| Pandichelvam Veeraiah1,2, Rick Voncken1, Kim Brouwers1,3, Julian Mevenkamp3, Job van den Hurk1,4, Joachim E Wildberger3, and Vera B Schrauwen-Hinderling3,5,6 | ||
1Scannexus (Ultra-High Field Imaging Center), Maastricht, Netherlands, 2Faculty of Health Medicine and Life sciences (FHML), Maastricht University, Maastricht, Netherlands, 3Department of Radiology and Nuclear Medicine, Maastricht University Medical Center (MUMC), Maastricht, Netherlands, 4Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands, 5Nutrition & Movement Sciences, Maastricht University, Maastricht, Netherlands, 6German Diabetes Center, Dusseldorf, Germany |
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Keywords: Spectroscopy, Muscle, Ultra-high field MRS, proton MR spectroscopy, Muscle Long echo time 1H-MRS has been used to determine in vivo acetylcarnitine (ACCT) concentrations in the skeletal muscle. At ultra-high field (UHF), STEAM-based 1H-MRS was used for this purpose, in combination with a knee birdcage coil. However, STEAM suffers from an inherent 50% signal loss and a knee coil often does not fit around the upper leg in obese volunteers. Here, we demonstrated that sLASER, in combination with a surface coil, provides high signal-to-noise ratio (SNR) and can be used as an alternative method at 7T to detect physiologically low ACCT concentrations at rest in both lean and obese volunteers. |
| 3688 | Computer 108
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Localized 31P Magnetic Resonance Spectroscopy of Normal Human Kidneys at 3T |
| Limin Zhou1, Keith Hulsey1, Durga Udayakumar1,2, Andrea J. Wiethoff3, and Ananth J. Madhuranthakam1,2 | ||
1Department of Radiology, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center, DALLAS, TX, United States, 3Novartis Institutes for BioMedical Research, Cambridge, MA, United States |
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Keywords: Spectroscopy, Kidney, Phosphorous (31P) MR spectroscopy (MRS), healthy volunteers Phosphorous (31P) MR spectroscopy (MRS) can measure high energy phosphate metabolism non-invasively in vivo, which can provide metabolic insights into kidney pathophysiology. However, obtaining spectra from healthy volunteers for reference is challenging. In this study, we investigate the feasibility of localized 31P MRS in kidneys of healthy volunteers with a 3T clinical MR scanner. 31P spectra were successfully obtained in 10 healthy volunteers with metabolite ratio calculated to provide information about the energy metabolism. |
| 3689 | Computer 109
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Feasibility of a multi-site and cross-platform liver 31P MRSI processing pipeline for three 7T clinical MRI vendors |
| Jabrane Karkouri1, Lieke van den Wildenberg2, Bobby Runderkamp3, Jeanine Prompers2, Paolo Cecchi4, Michela Tosetti4,5, Dennis Klomp2, and Christopher T. Rodgers1 | ||
1University of Cambridge, Cambridge, United Kingdom, 2Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, 3Department of Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, 4IMAGO7 Research Foundation, Pisa, Italy, 5Laboratory of Medical Physics and Magnetic Resonance, IRCCS Stella Maris, Pisa, Italy |
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Keywords: Spectroscopy, Non-Proton We present preliminary baseline results from three-vendor 7 T MRSI for applications on liver 31P MRS. Liver scans were performed on 21 healthy volunteers, at 4 sites and 3 different 7T MR scanner platforms. Data were analysed using a new Matlab pipeline combining the best methods from our labs. This pipeline is operator independent and we report here the liver metabolites as ratios of PME/PDE and Pi/ATP concentrations. The cross-site average PME/PDE was 0.63 ± 0.12, and the cross-site average Pi/ATP was 0.76 ± 0.11. This compares favourably with literature reports [Purvis et. al., 2017]. |
| 3690 | Computer 110
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Removal of lipid signals and other short T2 components in GRE-MRI and FID-MRSI using quadratic radio frequency phase increments |
| Lukas Hingerl1, Bernhard Strasser1, Gilbert Hangel1,2, Stanislav Motyka1, Fabian Niess1, Eva Niess1, Alexandra Lipka1, Dario Goranovic1, Philipp Lazen1, Stephan Gruber1, Siegfried Trattnig1,3, and Wolfgang Bogner1 | ||
1Department of Biomedical Imaging and Image-guided Therapy, Radiology and Nuclear Medicine, Medical University of Vienna, HFMR Centre, Vienna, Austria, 2Department of Neurosurgery, Medical University of Vienna, Vienna, Austria, 3Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria |
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Keywords: Spectroscopy, Spectroscopy, Lipid Fat Suppression Removal We present an elegant and easy to implement method for MRI and CSI steady-state sequences to remove or suppress lipids or other components with short transverse relaxation times by neither introducing additional pulses nor hardware and by just altering the excitation pulse phase. |
| 3691 | Computer 111
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High-Resolution 1H-MRSI of the Brain at 9.4T Integrating Relaxation Enhancement and Subspace Imaging |
| Yizun Wang1,2, Stanislav S. Rubakhin1,2,3, and Fan Lam1,2,4 | ||
1Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 4Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States |
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Keywords: Spectroscopy, Data Acquisition, MRSI Data Processing Ultrahigh-field systems offer sensitivity and specificity advantages for metabolite mapping using MRSI. We present here a method that integrates relaxation enhancement acquisition, a unique strategy leveraging higher fields, and subspace imaging, for high-resolution 1H-MRSI at a 9.4 T system. Both in vitro and in vivo experiments have been performed to demonstrate the feasibility of the proposed method. We are able to achieve significantly enhanced SNR compared to no relaxation enhancement and produce high-quality spatially-resolved spectra and high-resolution metabolite images using subspace imaging with 0.6×0.6×2 mm3 nominal resolution in 18 minutes or 1×1×2 mm3 in 10 minutes. |
| 3692 | Computer 112
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Tailoring a convolutional neural network towards spectral quantification and reconstruction of simulated 7T brain FID-MRSI data |
| Dario Goranovic1, Stanislav Motyka1, Bernhard Strasser1, Paul Weiser2, Georg Langs2, and Wolfgang Bogner1 | ||
1High Field MR Center - Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria, 2Computational Imaging Research Lab - Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria |
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Keywords: Spectroscopy, Brain The abstract investigates the possibilities of using convolutional neural networks for enhanced and robust spectral quantification of simulated 7T FID-MRSI brain spectra. The proposed network architecture predicts wavelet parameters for baseline correction, as well as spectral parameters and metabolite amplitudes for spectral reconstruction. The potential reduction in quantification times could thus mitigate some disadvantages of current MRSI processing techniques. |
| 3693 | Computer 113
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3D High-Resolution T1 Mapping of Brain Metabolites |
| Yibo Zhao1,2, Rong Guo1,3, Yudu Li1,4, Wen Jin1,2, Yao Li5, Jie Luo5, and Zhi-Pei Liang1,2 | ||
1Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Siemens Medical Solutions USA, Inc., Urbana, IL, United States, 4National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 5School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China |
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Keywords: Spectroscopy, Relaxometry In MRSI studies, T1 values of metabolites are desirable for correcting relaxation and B1 inhomogeneity effects, and for evaluating microenvironmental changes in pathological conditions. Current metabolite T1 mapping has been limited to single-voxel or single-slice experiments due to SNR and imaging time constraints. In this work, we demonstrated the feasibility of 3D high-resolution T1 mapping of brain metabolites using a novel data acquisition and processing method featuring physics-based low-rank tensor modelling and FID acquisitions. The proposed method has been validated using phantom and in vivo data, producing encouraging results. |
| 3694 | Computer 114
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Compressed Sensing for MRSI with Concentric Ring Trajectories at 7 T |
| Bernhard Strasser1, Ovidiu C Andronesi2, Lukas Hingerl1, Stanislav Motyka1, Siegfried Trattnig1, Wolfgang Bogner1, and Antoine Klauser3 | ||
1Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland |
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Keywords: Spectroscopy, New Trajectories & Spatial Encoding Methods We show the feasibility of compressed sensing for MRSI using concentric ring trajectories. Four volunteers (three for 2D- and one for 3D-MRSI) were measured in about 9 minutes (2D-MRSI), and 14 minutes (3D-MRSI) using an FID-based MRSI sequence at 7 T. An iterative compressed sensing reconstruction including coil sensitivities and a total general variation spatial regularization was performed with retrospective undersampling factors of 1.5, 2.0 and 2.9. RMSE values were below 22 % and SSIM values above 0.8 for medium accelerations below 2.9 in the 2D case. The metabolic maps and spectra are similar to the gold standard without acceleration. |
| 3695 | Computer 115
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Implementation of Zoom MRSI at 7T for High-resolution GABA and Glutamate Mapping |
| Onur Ozyurt1, Diana Rotaru2, Nicholas Farley3, Zoe Kourtzi2, Guy Williams1, and Uzay Emrah Emir3,4 | ||
1Wolfson Brain Imaging Center, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, 2Department of Psychology, University of Cambridge, Cambridge, United Kingdom, 3School of Health Sciences, Purdue University, West Lafayette, IN, United States, 4Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States |
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Keywords: Spectroscopy, Brain, GABA, Glutamate, MRSI High-resolution neurochemical mapping using 2D zoom or reduced field of view (rFOV) magnetic resonance spectroscopy (MRSI) enables the high-resolution metabolic assessment of brain regions that is difficult to probe with standard MRSI sequences. To our knowledge this is the first study to have demonstrated the application of zoom MRSI at 7T for GABA and glutamate mapping. |
| 3696 | Computer 116
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Reproducibility of non-localized 13C-MRS using a quadrature surface coil for assessing hepatic carbohydrate metabolism in humans |
| Marc Jonuscheit1,2, Benedict Korzekwa1,2, Yuliya Kupriyanova1,2, Julian Mevenkamp3, Michael Roden1,2,4, and Vera B. Schrauwen-Hinderling1,2,3 | ||
1Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany, 2German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany, 3Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, 4Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany |
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Keywords: Spectroscopy, Spectroscopy, 13C-MRS, Quadrature Coil, Absolute Quantification We determined day-to-day variation and intra-session reproducibility of 13C-MRS based hepatic glycogen quantification by phantom replacement, using a custom-created rigid quadrature surface coil and determining the C1-glycogen signal in eight healthy volunteers. The quadrature coil allows measurements at high distances, which can be important for applications in overweight and obese people. Coefficients of variation were less than 22% for day-to-day variation and less than 9% for intra-session reproducibility (with repositioning of volunteer). In conclusion, our 13C-MRS protocol yields robust absolute concentrations of the hepatic glycogen and the day-to-day variation assessed here can be the basis for sample size calculations. |
| 3697 | Computer 117
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Effects of denoising on diffusion-weighted MRS data |
| Guglielmo Genovese1 and Małgorzata Marjańska1 | ||
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States |
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Keywords: Spectroscopy, Data Processing, Diffusion-Weighted MRS, High Field (3T), Denoising, Low-Rank Model Diffusion-weighted (DW) MRS is a useful tool for detecting microstructural changes linked to neurological diseases. However, DW-MRS suffers from low signal-to-noise ratio, which makes human application extremely difficult. To overcome this issue, a denoising algorithm based on low-rank approximation was recently utilized. Here, effects of the application of low-rank based denoising algorithm to DW-MRS data are described based on synthetic data. Severely artifactually low group SDs for the apparent diffusion coefficients (ADCs) of all metabolites and biased mean ADC values were observed after denoising. These findings suggest that low-rank approximations are detrimental to a reliable quantification of ADCs of metabolites. |
| 3698 | Computer 118
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Diffusion-weighted MR spectroscopy of the prostate |
| Angeliki Stamatelatou1, Rudy Rizzo2,3, Kadir Simsek4, Jack J.A. van Asten1, Arend Heerschap1, Tom WJ Scheenen1, and Roland Kreis2,3 | ||
1Department of Medical Imaging, Radboud University Medical Center, Nijmegen, Netherlands, 2Magnetic Resonance Methodology, Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Bern, Switzerland, 3Translational Imaging Center, sitem-insel, Bern, Switzerland, 4Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom |
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Keywords: Spectroscopy, Diffusion/other diffusion imaging techniques Diffusion-weighted Magnetic Resonance Spectroscopy (DW-MRS) is ideally suited to explore complex microstructure with metabolites selectively distributed in different subspaces. So far this technique was applied in brain and muscle only. In this work, we explored DW-MRS for the first time in the prostate, an organ, with potentially more motion problems. Thus, dedicated acquisition and post-processing techniques were used including the measurement of water next to that of metabolites for corrections. ADC values of citrate, total choline, total creatine and spermine were estimated and evaluated according to the compartmental structure of the prostate indicating hindered metabolite diffusion in the luminal space. |
| 3699 | Computer 119
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Comparison of short-interval afferent inhibition measures with tonic GABA and Glutamate levels |
| Michal Považan1, Mads Just Madsen1, and Leo Tomasevic1 | ||
1Danish Research Centre for Magnetic Resonance, Hvidovre, Denmark |
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Keywords: Spectroscopy, Neuroscience The neurochemical substrate of the measures observed with transcranial magnetic stimulation remains unclear. MR spectroscopy may provide valuable insights into understanding the synaptic GABAergic and glutamatergic activity, however studies comparing these methods haven’t provided an adequate explanation. We aimed to compare GABA and glutamate concentrations with short-interval afferent inhibition measured with TMS. We found positive correlation between the amount of inhibition and tonic GABA levels, however this finding needs to be carefully scrutinized. |
| 3700 | Computer 120
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Ex-vivo MR spectroscopy in paraformaldehyde-fixed mouse brain |
| Alireza Abaei1, Dinesh K Deelchand 2, Stefano Antonucci3, Jelena Scekic-Zahirovic3, Florian olde Heuvel3, Francesco Roselli3, and Volker Rasche4 | ||
1Ulm University, Ulm, Germany, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 3German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany, 4Core Facility Small Animal Imaging (CF-SANI), University of Ulm, Ulm, Germany |
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Keywords: Spectroscopy, Spectroscopy, in vivo ex vivo MRS The goal of this study is to demonstrate the feasibility and reliability of metabolite characterization by MR spectroscopy ex vivo in order to maximize the information obtained from a single brain specimen, without the limitations such as scanning time, degraded MRI quality due to intervening tissue and motion artifacts. We demonstrate that ex-vivo spectroscopy obtained after rapid PBS/PFA perfusion is strongly correlated with the MR spectrum previously acquired in the same animal but in vivo but distinct abnormalities due to hypoxia and incomplete fixation do appear; the quality of the spectrum quickly degrades upon longer fixation times. |
| 3838 | Computer 81
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FMRI-based language mapping at 1.5 and 3T: the influence of methodological choices. |
| Khaliesah Bolhassan1,2, Rachael Franklin3, Enrico De Vita4, Jozef Jarosz2, and Marco Borri2 | ||
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, 2Neuroradiology, King's College Hospital, London, United Kingdom, 3MRI Physics, Guy’s and St Thomas NHS Foundation Trust, London, United Kingdom, 4Radiology Department, Great Ormond Street Hospital for Children, London, United Kingdom |
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Keywords: fMRI (task based), Data Analysis This work aims to assess the influence of methodological aspects in fMRI language mapping at 1.5T and 3T. Probability maps from healthy volunteer cohorts were compared to a published reference using a Dice Index vs probability threshold plot. T-value normalisation to the peak within the classic Broca/Wernicke’s language area as well as the inclusion of additional language tasks increased overlap to the reference. The extent of reproducible activation was larger at 3T. |
| 3839 | Computer 82
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Dynamic analysis of resting-state brain fMRI signal from a novel perspective: Avalanche |
| Junlin Guo1, Nazirah Mohd Khairi1, Lyuan Xu1,2, and Don Mitchell Wilkes1 | ||
1Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States |
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Keywords: fMRI (resting state), Brain, Spatiotemporal The human brain, at rest, is complex and many functional studies focus on the brain patterns around criticality. This work addresses a novel perspective, the avalanche, in resting-state fMRI. In this work, we design two data-driven signal modeling approaches that dynamically measure and visualize the signal entropy from both spatial and temporal aspects. The first approach applies a clustering-based scheme with the Markov chain. The second method utilizes the autoregressive model with a sliding window. The results show a consistent, less complex pattern at the avalanche state, from which the interpretation of the brain can be clearer than at criticality. |
| 3840 | Computer 83
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Investigation of cerebral blood flow and volume changes during positive and negative BOLD responses at 3T |
| Ratnamanjuri Devi1, Torsten Schlumm1, Toralf Mildner1, and Harald E Möller1 | ||
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany |
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Keywords: fMRI (task based), Arterial spin labelling, Vascular Space Occupancy CBF and CBV changes were measured sequentially, in regions of positive and negative BOLD responses, using a multi-echo center-out readout, known to reduce BOLD contaminations in pCASL and VASO measurements due to its short echo times. The CBV-CBF coupling was found to differ between positive and negative BOLD regions. The temporal relation of the CBF and VASO timecourses to their corresponding T2* timecourses, on the other hand, was found to be almost identical in the two ROIs. |
| 3841 | Computer 84
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Evaluation of neuronal feed-forward control of cerebral blood flow in negative BOLD response |
| Ratnamanjuri Devi1, Jöran Lepsien1, Kathrin Lorenz1, Torsten Schlumm1, Toralf Mildner1, and Harald E Möller1 | ||
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany |
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Keywords: fMRI (task based), Arterial spin labelling The application of a simplistic model of neuronal control of changes in cerebral blood flow and oxygen metabolism to experimental data in regions of the positive and negative BOLD response, suggested differences in neuronal contributions and inhibitory control of changes in cerebral blood flow between the two regions. |
| 3842 | Computer 85
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Whole-brain, gray and white matter time-locked functional signal changes with simple tasks and model-free analysis |
| Kurt G Schilling1, Muwei Li1, Francois Rheault2, Yurui Gao1, Leon Y Cai3, Yu Zhao1, Zhongliang Zu1, Zhaohua Ding1, Adam W Anderson3, Bennett A Landman3, and John C Gore1 | ||
1Vanderbilt University Medical Center, Nashville, TN, United States, 2Sherbrooke University, Sherbrooke, QC, Canada, 3Vanderbilt University, Nashville, TN, United States |
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Keywords: fMRI, White Matter Recent studies have revealed that blood oxygenation-level dependent (BOLD) signal changes correlate with task timings throughout a majority of the cortex, challenging the idea of sparse and localized brain functions, and highlighting the pervasiveness of potential false negative fMRI findings. However, these studies have focused on gray matter only. We extend the analysis to white matter and find widespread BOLD signal changes in both white and gray matter, challenging the idea of sparse functional localization, but also the prevailing wisdom of treating white matter BOLD signals as artefacts to be removed. |
| 3843 | Computer 86
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Neurovascular coupling of the human brain in complex naturalistic stimuli viewing |
| Hsin-Ju Lee1,2, Emily Rutledge1,3, Jiahui Veron Cheng1,4, Lauri Nummenmaa5, Severi Santavirta5, and Fa-Hsuan Lin1,2 | ||
1Physical Sciences Platform, Sunnybrook Research institute, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3University of Waterloo, Ｗaterloo, ON, Canada, 4University of Toronto, Toronto, ON, Canada, 5Turku PET Centre, University of Turku, Turku, Finland |
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Keywords: fMRI (task based), fMRI (task based), EEG-fMRI Simultaneously acquired EEG and fMRI data allow for elucidating the neurovascular coupling. Here, we use temporally sparse fast fMRI and continuous EEG to study the correlations between hemodynamic signals and neural oscillations across the cerebral cortex during movie watching. |
| 3844 | Computer 87
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Using PINS pulses to saturate inflow effects from slice gaps in functional MRI |
| Shota Hodono1, Chia-yin Wu1,2,3, Carl Dixon1, Donald Maillet1, Jin Jin4, Jonathan R Polimeni5,6, and Martijn A Cloos1 | ||
1Centre for Advanced Imaging, The University of Queensland, St Lucia, Australia, 2ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St. Lucia, Australia, 3chool of Information Technology and Electrical Engineering, The University of Queensland, St. Lucia, Australia, 4Siemens Healthcare Pty Ltd, Brisbane, Australia, 5Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 6Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Keywords: fMRI, Velocity & Flow In this work, we demonstrate the use of PINS pulses to mitigate unwanted inflow effects in 2D multi-slice sequences. A PINS pulse was played prior to slice-selective excitation to saturate the magnetization within all slice gaps. Bloch simulation and flow-phantom experiments show inflow effects can be removed completely. Functional scans using twice-refocused spin echo suggest that inflow effects may have noticeable contributions to SE-BOLD fMRI response. This PINS implementation allows us to further understand fMRI signal dynamics by modulating the inflow effect. |
| 3845 | Computer 88
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Intravascular Shifted fMRI Contrast for Visual Stimulations at 3 Tesla Using DANTE-Prepared Dual-Echo EPI |
| Linqing Li1, Yuhui Chai2, Andy John Derbyshire1, and Peter Bandettini3 | ||
1Functional MRI Facility, National Institute of Mental Health, Bethesda, MD, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Section on Functional Imaging Methods, National Institute of Mental Health, Bethesda, MD, United States |
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Keywords: fMRI, fMRI (task based), Intravascular fMRI contrast, extravascular fMRI contrast By using dual-echo DANTE-EPI for functional visual stimulation studies, the contrast of fractions of intravascular signal to total signal change can be generated. We show an intravascular shifted (IVS) contrast can provide simultaneous visualization of intra-extra vascular contrast under different frequencies of visual stimulations at 3T. |
| 3846 | Computer 89
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Cerebellar gray matter volume and cerebellum-cerebral connectivity associated with freezing of gait in patients with multiple system atrophy |
| Huaguang Yang1, Weiyin Vivian Liu2, Liang Li1, Zhi Wen1, Lanhua Hu1, XiaoGuang Luo3, and Yunfei Zha1 | ||
1Renmin Hospital of Wuhan University, Wuhan, China, 2MR Research, GE Healthcare, Wuhan, China, 3Department of Neurology, The First Affiliated Hospital of South University of Science and Technology, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, ShenZhen, China |
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Keywords: fMRI (resting state), Parkinson's Disease Cerebellum is responsible for posture and gait control. 65.93% of patients with multiple system atrophy experienced FOG. Patients with the damaged cerebellar locomotor region had gait-freezing-like symptoms, suggesting that the cerebellum may be involved in the occurrence and development of FOG symptoms. This study suggested that the cerebellum volume atrophy may be involved in FOG development in MSA patients and subsequently induce functional abnormality in the cerebellum-cerebral circuit. This study provided neuroimaging evidence for clinical understanding of cerebellum role in MSA patients with FOG injury. |
| 3847 | Computer 90
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Quantifying Organizational Changes of Functional Connectivity Linked to Hypertension in Resting-State Functional MRI |
| William D. Reeves1, Ishfaque Ahmed1, Brooke S. Jackson2, Wenwu Sun1, Michelle L. Brown3, Celestine F. Williams3, Catherine L. Davis3, Jennifer E. McDowell2, Nathan E. Yanasak4, Shaoyong Su3, and Qun Zhao1 | ||
1Department of Physics, University of Georgia, Athens, GA, United States, 2Department of Psychology, University of Georgia, Athens, GA, United States, 3Georgia Prevention Institute, Medical College of Georgia, Augusta, GA, United States, 4Department of Radiology and Imaging, Medical College of Georgia, Augusta, GA, United States |
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Keywords: fMRI (resting state), Hypertension Using a graph theory approach, functional connectivity differences in a 52 (32 hypertensive, 20 normotensive) subject cohort were tracked using resting-state fMRI. A null generation modification to a difference degree test (DDT) is profiled that resulted in increased true positivity rates in simulations while maintaining nominal false positivity rates. Applying the modified DDT to the hypertension cohort resulted in the discovery of 7 brain regions that exhibit significant groupwise differential expression along with 33 unique differentially expressed connections to other areas in the brain. The results presented agree with previous studies and represent a promising application of the modified DDT. |
| 3848 | Computer 91
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Altered resting state networks associated with REM sleep behavioral disorder in Parkinson’s disease |
| Destaw Bayabil Mekbib1, Miao Cai2, Weiying Dai3, Xiaoli Liu4, and Li Zhao1 | ||
1Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China, 2Neurology, Zhejiang Hospital, Hangzhou, China, 3Computer Science, Binghamton Univeristy, State University of New York, Binghamton, NY, United States, 4Zhejiang Hospital, Hangzhou, China |
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Keywords: fMRI (resting state), Parkinson's Disease Resting-state functional MRI has played a fundamental role in the study of Parkinson’s disease (PD) with rapid eye movement sleep behavior disorder (RBD). In this work, we investigated changes in functional connectivity within and between resting-state networks and their relationship to global fluctuations in 13 PD with RBD, 28 PD without RBD, 6 RBD without PD, and 20 healthy controls. Based on an in-house reliable data selection strategy, unique effects on the lateral visual network in RBD patients and on the sensorimotor network in PD patients were found. These may provide novel clues to understanding the pathology and improve diagnosis. |
| 3849 | Computer 92
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Bayesian and lagged general linear modelling strategies in breath-hold induced cerebrovascular reactivity mapping with muti-echo BOLD fMRI |
| Genevieve Hayes1, Joana Pinto1, Stefano Moia2, Martin Craig3, Michael Chappell3, Cesar Caballero-Gaudes2, and Daniel P Bulte1 | ||
1Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom, 2Basque Centre on Cognition, Brain and Language, Donostia-San Sebastian, Spain, 3Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom |
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Keywords: fMRI, Blood vessels, Cerebrovascular reactivity Cerebrovascular reactivity (CVR), the ability of blood vessels to dilate and constrict in response to a vasoactive stimulus, is an important indicator of cerebrovascular health and can be estimated using BOLD functional MRI. In this work, we evaluated a novel variational Bayesian method for mapping CVR dynamics which yielded similar CVR results and reproducibility to a time-shifted, “lagged” general linear model approach, and uncovered the need for more research into negative CVR. This novel approach is more time efficient and has the potential to improve CVR mapping by incorporating non-linear modelling and physiologically meaningful information (in the form of priors). |
| 3850 | Computer 93
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Cerebrovascular reactivity mapping using breath-hold BOLD-fMRI: comparison of signal models when using voxelwise lag optimization |
| Catarina Domingos1, Inês Esteves1, Ana R. Fouto1, Amparo Ruiz-Tagle1, Gina Caetano1, and Patrícia Figueiredo1 | ||
1Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal |
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Keywords: fMRI, fMRI We investigate the best modeling approach for mapping cerebrovascular reactivity (CVR) using voxelwise lag optimization. We considered two types of regressors (Block, PetCO2), three convolution models (no convolution, single gamma, double gamma), and a variable haemodynamic delay. We found that the CVR values obtained when using the PetCO2 signal without convolution, or convolved with a single gamma, are better than those obtained with the canonical HRF (double gamma, time-to-peak = 6s), while convolution with a canonical HRF remains the best option when using a Block design. |
| 3851 | Computer 94
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Cerebrovascular reactivity mapping using intermittent breath modulation: temporal resolution dependence and comparisons with CO2 inhalation |
| Beini Hu1, Lori Donaldson1, Parimal Joshi1, Lincoln Kartchner1, Sara Akar1, and Peiying Liu1 | ||
1Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Baltimore, Baltimore, MD, United States |
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Keywords: fMRI, Neuro Cerebrovascular reactivity (CVR) is typically measured using a carbon dioxide (CO2) stimulus combined with BOLD fMRI. However, this requires considerable subject cooperation. Although resting-state BOLD fMRI has shown its potential to generate CVR maps, the CVR results could be unreliable due to little fluctuation in some subjects’ spontaneous breathing. A new method utilizing intermittent breath modulation requires no gas-inhalation and presents higher sensitivity than resting-state CVR mapping. In this study, we investigated the effect of temporal resolution on CVR mapping obtained from breath modulation BOLD data. Our results showed that good CVR quality can be achieved with TR of 0.72s. |
| 3852 | Computer 95
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Toward vessel-suppressed cerebrovascular reactivity (CVR) mapping by using crusher gradients |
| Yimei Cao1, Hongli Fan1, Cuimei Xu1, and Hanzhang Lu1 | ||
1Department of Radiology, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: fMRI, fMRI Cerebrovascular reactivity (CVR) is an indicator of cerebrovascular reserve and provides important information about vascular health in a range of brain conditions and diseases. However, current CVR maps often have artifactual bright spots in arterial/venous areas due to the complexity of the BOLD signal mechanism. In this work, we proposed a novel CVR acquisition scheme by adding single-direction or varying-direction crusher gradients to the BOLD sequence. The results demonstrated that these modified sequences could successfully suppress large-vessel artifacts in CVR map. |
| 3853 | Computer 96
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Clinical Functional MRI-derived Probabilistic Template of Primary Language Areas of Patients with Brain Tumors |
| Jian Ming Teo1,2, Jina Lee3, Ping Hou1, Vinodh A Kumar3, Kyle R Noll4, Sujit S Prabhu5, and Ho-Ling Liu1 | ||
1Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States, 3Department of Neuroradiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 4Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 5Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX, United States |
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Keywords: fMRI, Data Processing This study aims to develop a functional template of primary language areas based on 306 presurgical language fMRI scans from 102 patients with brain tumors. The template was constructed from voxelwise probabilistic distribution of fMRI results of three common clinical language paradigms. An independent dataset of 38 patients was used to test the template from this study and compare with a template derived from the meta-analysis of 1101 published studies. The results showed that our template agreed better with the test dataset, with significantly higher dice coefficients in both anterior and posterior primary language areas, comparing with the literature-based template. |
| 3854 | Computer 97
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Slope of the spectrum of low-frequency BOLD signal relation to the connectivity strength |
| Kazuhiro Nakamura1 and Toshibumi Kinoshita1 | ||
1Research Institute for Brain and Blood Vessels Akita, Akita, Japan |
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Keywords: fMRI (resting state), fMRI (resting state), spectrum analysis For the valuation of BOLD fluctuations, we have investigated the slope of the spectrum (SLOPE) to exclude the respiratory and heartrate fluctuation. Functional connectivity (ROI to ROI) was evaluated by Conn v19.b software. The SLOPE was evaluated in the frequency range of 0.01 – 0.1Hz. Maximum connectivity in each ROI correlated well with the value of SLOPE, but the mean connectivity did not. Therefore, it will be possible to evaluate the strength of connectivity of rs-fMRI by evaluating SLOPE. |
| 3855 | Computer 101
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A Magnetic Resonance Spectroscopy Method in Characterization of Urine Metabolomics for Prostate Cancer |
| Leo L Cheng1, Anna-Laura M Hasubek1, and Adam S Feldman2 | ||
1Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 2Massachusetts General Hospital, Boston, MA, United States |
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Keywords: Spectroscopy, Prostate, Metabolomics Currently, Prostate Cancer (PC) diagnosis is achieved either through invasive measures, like biopsies, or imaging techniques, such as sonography, CT, and MRI. The biomarker PSA in blood is used for screening, however its use is considered controversial. It doesn’t show to reduce PC all-cause mortality and PSA screening comes with a high number of false-positive results and associated risks. Here, using HRMAS MRS, we studied human urine samples obtained from prostate cancer patients and healthy controls to reveal potential PC-associated metabolomic changes, which may assist with early and non-invasive PC diagnosis and screening. |
| 3856 | Computer 102
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Changes in Aspartate Metabolism in the medial-prefrontal cortex of Nicotine Addicts Based on J-edited Magnetic resonance spectroscopy |
| Miaomiao Yu1, Liangjie Lin2, Ke Xu1, Man Xu1, Jianxin Ren1, Xiaoyu Niu1, Xinyu Gao1, Mengzhe Zhang1, Zhengui Yang1, Jinghan Dang1, Qiuying Tao1, Shaoqiang Han1, Weijian Wang1, Jingliang Cheng1, and yong zhang1 | ||
1Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Clinical and Technical Support, Philips Healthcare, Beijing, China |
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Keywords: fMRI, Metabolism, Hydrogen proton magnetic resonance spectroscopy (1H MRS) Cigarette smoking harms nearly every organ of the body, causes many diseases, and reduces the health of smokers in general. Our study aims to explore the changes of aspartate (Asp) levels in the medial prefrontal cortex of patients with nicotine addiction using the J-edited 1H MRS technique. Results showed that the Asp level in medial prefrontal of nicotine addicts is relatively increased, suggesting that the metabolism of aspartate may play a key role in nicotine dependence. |
| 3857 | Computer 103
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Neurochemical profile of major depressive disorder in adolescents: 7 T MRS study |
| Guglielmo Genovese1, Paul E. Croarkin2, Can Ozger2, and Małgorzata Marjańska1 | ||
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, United States |
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Keywords: Spectroscopy, Psychiatric Disorders, Ultra-High Field 7 T, Adolescents, Neuro, Major Depressive Disorder Major depressive disorder in adolescents (MDD) is a substantial public health problem. Existing treatments are often ineffective and do not target relevant neurobiological markers. It has been hypothesized that neurobiological mechanism underlying depression involves a dysfunction of the excitatory/inhibitory neurotransmitters. Here, the neurochemical profile from the occipital lobe of twenty adolescents with MDD and twenty-four age-matched healthy volunteers (HV) were acquired at 7 T. Larger SDs were observed for some metabolites in MDD versus HV and suggest heterogeneity of depression severity in the MDD cohort. Positive correlation in MDD between aspartate and GABA could be indicative of a neurotransmitter imbalance. |
| 3858 | Computer 104
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Efficient Myocardial Spectroscopy combining Metabolite-Cycling with Respiratory Bellows at 3T |
| Fabian Bschorr1, Tobias Speidel1, Niklaus Zoelch2,3, Andreas Hock4, Alireza Abaei5, and Volker Rasche1 | ||
1Ulm University Hospital, Ulm, Germany, 2Zurich University Hospital of Psychiatry, University of Zurich, Zurich, Switzerland, 3Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland, 4Zurich University of Applied Sciences, Wädenswil, Switzerland, 5Core Facility Small Animal Imaging (CF-SANI), University of Ulm, Ulm, Germany |
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Keywords: Spectroscopy, Cardiovascular Despite its diagnostic values1-4, the application of cardiac spectroscopy (CMRS) in clinical routine is generally limited by technical challenges and long scan times. A protocol for CMRS is proposed using metabolite-cycling, local, ECG-triggered shimming, ECG-triggering and a respiratory bellows. The protocol is evaluated in a volunteer cohort and provides myocardial triglyceride content (MTGC) quantification results that correlate well intrasession- (r=0.98, p<0.001) and intersession-wise (r=0.95, p<0.001). Thus, a good repeatibility and technical stability for the quantification of MTGC could be achieved with an average scan time of 440s at 3T. |
| 3859 | Computer 105
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Comparison of Magnetic Resonance Spectroscopy Data Acquired with Hybrid PET-MRI and Standalone MRI Scanners |
| Aditya Bhattacharya1, Benjamin B. Risk2, and Candace C. Fleischer3,4 | ||
1Neuroscience, Georgia Institute of Technology, Atlanta, GA, United States, 2Biostatistics and Bioinformatics, Emory University, Atlanta, GA, United States, 3Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 4Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States |
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Keywords: Spectroscopy, PET/MR Magnetic resonance spectroscopy (MRS) is a powerful tool for quantifying metabolite concentrations, but spectral quality has not been thoroughly explored in hybrid MRI scanners. Using repeated measurements in a brain phantom and healthy volunteer, we determined the reproducibility and accuracy of MRS data on two systems, a hybrid GE PET-MRI (3.0 T) and Siemens 3.0 T MRI. Spectra acquired using the PET-MRI scanner produced metabolite concentrations with higher accuracy and lower variance across repeated measurements compared to the standalone MRI, suggesting spectral quality is not hindered by the hybrid system. |
| 3860 | Computer 106
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Neurochemical differences between 1p/19q codeleted and non-codeleted gliomas assessed by in vivo magnetic resonance spectroscopy |
| Francesca Branzoli1, Roberto Liserre2, Dinesh Deelchand3, Pietro Luigi Poliani4, Franck Bielle5, Lucia Nichelli6, Marc Sanson1,7, Stéphane Lehéricy1,6,8, and Małgorzata Marjańska3 | ||
1Sorbonne University, UMR S1127, INSERM U1127, CNRS UMR 7225, Paris Brain Institute - ICM, Paris, France, 2Department of Radiology, Neuroradiology Unit, ASST Spedali Civili University Hospital, Brescia, Italy, 3Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 4Pathology Unit, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy, 5Laboratory R Escourolle, University Hospital La Pitié Salpêtrière, Paris, France, 6Department of neuroradiology, University Hospital La Pitié Salpêtrière, Paris, France, 7Department of neurology 2, University Hospital La Pitié Salpêtrière, Paris, France, 8Center for Neuroimaging Research (CENIR), ICM, Paris, France |
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Keywords: Spectroscopy, Cancer Mutations in the genes encoding for isocitrate dehydrogenase (IDH), and 1p/19q codeletion are genetic alterations that can be often found in low-grade gliomas and are associated with better prognosis and response to treatment. Nevertheless, the biological effects of the 1p/19q codeletion are still not well known. In this study, we compared the neurochemical profile of IDH-mutated, 1p/19q codeleted gliomas and their non-codeleted counterparts using in vivo magnetic resonance spectroscopy. We showed that the only metabolite that differed significantly between the two groups was cystathionine, pointing to this metabolite as the most useful biomarker for the identification of 1p/19q codeleted gliomas.
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| 3861 | Computer 107
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Correlation of NAAG level in the bilateral medial prefrontal cortex with nicotine dependence score in adult cigarette smokers |
| Liangjie Lin1, Miaomiao Yu2, Ke Xu2, Man Xu2, Jianxin Ren2, Xiaoyu Niu2, Xinyu Gao2, Mengzhe Zhang2, Zhengui Yang2, Jinghan Dang2, Qiuying Tao2, Shaoqiang Han2, Weijian Wang2, Jingliang Cheng2, and yong zhang2 | ||
1Clinical and Technical Support, Philips Healthcare, Beijing, China, 2Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China |
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Keywords: Spectroscopy, Metabolism, Hydrogen proton magnetic resonance spectroscopy (1H MRS) Smoking can cause cancer, heart disease, stroke, lung diseases, diabetes, and chronic obstructive pulmonary disease including emphysema and chronic bronchitis. Our study aims to explore the correlation between neurotransmitter levels in the medial prefrontal cortex of patients with nicotine addiction (NA) using the J-edited 1H MRS technique. Results showed that the N-acetylaspartylglutamate (NAAG) level in medial prefrontal of nicotine addicts was significantly correlated with the score of Fagerstrom Test for Nicotine Dependence, suggesting that the metabolism of NAAG may play a key role in nicotine dependence patients. |
| 3862 | Computer 108
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Comparing 7 T FID-CRT-MRSI with 3 T MRF in High-Grade Gliomas |
| Philipp Lazen1, Sukrit Sharma2, Cornelius Cadrien1, Wolfgang Marik3, Thomas Roetzer-Pejrimovsky4, Eva Niess2, Lukas Hingerl2, Stephan Gruber2, Bernhard Strasser2, Barbara Kiesel1, Adelheid Wöhrer4, Matthias Preusser5, Julia Furtner3,6, Wolfgang Bogner2,7, Georg Widhalm1, Siegfried Trattnig2,7,8, Karl Rössler1,7, and Gilbert Hangel1,2,7 | ||
1Department of Neurosurgery, Medical University of Vienna, Vienna, Austria, 2High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 3Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 4Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria, 5Division of Oncology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria, 6Medical Image Analysis and AI, Danube Private University, Krems, Austria, 7Christian Doppler Laboratory for MR Imaging Biomarkers, Vienna, Austria, 8Institute for Clinical Molecular MRI, Karl Landsteiner Society, St. Pölten, Austria |
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Keywords: Spectroscopy, Brain We compared 7T MRSI-derived metabolic ratios with T1 and T2 maps from MR fingerprinting in a cohort of glioma patients by defining hotspots and calculating Dice similarity coefficients (DSCs) between them and a segmentation. Notable high DSCs were 0.799 for tCho/NAA vs T2 and 0.753 for Gln/NAA vs T1. We also investigated values for T1, T2, and metabolite ratios in tumors, hotspots, and a control region, with the median relaxation times being T1=1610 ms and T2=79 ms in the tumor, and T1=964 ms and T2=46 ms in NAWM. |
| 3863 | Computer 109
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Altered cortical metabolism contributes to cognitive deficits in a healthy military cohort |
| Julie M Joyce1,2, Kristin Heaton3, Huijun J Liao2, and Alexander P Lin2 | ||
1cBRAIN, Department of Child and Adolescent Psychiatry, Psychosomatics, and Psychotherapy, Ludwig-Maximilians-Universität, Munich, Germany, 2Center for Clinical Spectroscopy, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 3Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA, United States |
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Keywords: Spectroscopy, Neuro, Military The selection of control groups is of increasing interest in military research. Here, we used single voxel magnetic resonance spectroscopy (MRS) to probe cortical metabolism in the anterior and posterior cingulate gyri, temporal lobe and parietal white matter in healthy military service members and civilian controls. Computerized neuropsychological tests were administered to evaluate neurocognitive abilities. We identified higher incidence of cognitive deficits in military service members relative to civilian controls as well as associations between neurometabolite levels and poor cognitive performance. |
| 3864 | Computer 110
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In situ determination of pH in brain tissue using postmortem 1H-MRS |
| Sabina Frese1, Dominic Gascho2, Michael Thali2, Sebastian Kozerke1, and Niklaus Zölch2,3 | ||
1Institute for Biomedical Engineering, ETH Zürich, Zürich, Switzerland, 2Institute for Forensic Medicine, University of Zurich, Zürich, Switzerland, 3University Hospital for Psychiatry, University of Zurich, Zürich, Switzerland |
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Keywords: Spectroscopy, Spectroscopy Postmortem, relatively low pH values have been described and reported to be dependent on the cause of death and the duration of the agonal phase. Using 1H-MRS on decedents and subsequent control pH measurements in collected samples, we investigated to what extent the pH dependence of peak positions of acetate and lactate are suitable to detect such low pH values non-invasively. We found that the measured chemical shift of acetate and corresponding pH value follow a simulated titration curve. Hence, acetate is a promising candidate to detect low postmortem brain pH for forensic investigations. |
| 3865 | Computer 111
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Novel urease inhibitor as potential treatment of hepatic encephalopathy led to brain glutamine decrease |
| Dunja Simicic1,2, Diana Evstafeva3, Filip Ilievski3, Yinyin Bao3, Sunghyun Kang3, Dario Sessa4, Stefanita-Octavian Mitrea1,2, Katarzyna Pierzchala1,2,5, Jean-Christophe Leroux3, and Cristina Cudalbu1,2 | ||
1CIBM Center for Biomedical Imaging, Lausanne, Switzerland, 2Animal Imaging and Technology, EPFL, Lausanne, Switzerland, 3Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland, 4Swiss Center for Liver Disease in Children, University Hospitals Geneva, Geneva, Switzerland, 5Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland |
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Keywords: Spectroscopy, Brain, Metabolism, Hepatic Encephalopathy, proton Type C hepatic encephalopathy (HE) is a severe neuropsychiatric disorder associated with chronic liver disease. Ammonia (partially produced in the gut by bacterial urease activity) has been pinpointed to explain the observed neurological alterations in HE and connected with the increase in brain Gln measured using 1H-MRS. As such current treatment strategies focus on either reducing ammonia production and absorption or on promoting its elimination. We showed that targeting urease activity using the urease inhibitor 2-octynoHA has a beneficial effect in reducing blood ammonia levels and reducing brain Gln measured using 1H-MRS at 9.4T in the cerebellum. |
| 3866 | Computer 112
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Cerebral glucose quantification using 1H short-TE STEAM spectroscopy at 7T: Influence of macromolecule signals |
| Hideto Kuribayashi1, Yuta Urushibata1, Thuy Ha Duy Dinh2, Hirohiko Imai3, Sinyeob Ahn4, Ravi Teja Seethamraju5, Tadashi Isa2, and Tomohisa Okada2 | ||
1Siemens Healthcare K.K., Tokyo, Japan, 2Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan, 3Kyoto U Graduate School of Informatics, Kyoto, Japan, 4Siemens Medical Solutions, Berkeley, CA, United States, 5Siemens Medical Solutions, Boston, MA, United States |
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Keywords: Spectroscopy, Neuro, glucose The ability of conventional 1H short-TE STEAM spectroscopy at 7T was investigated to quantitate cerebral glucose. Spectra were analyzed using LCModel with the standard 7T STEAM basis set and with that plus macromolecule basis set. With the evaluation of Cramér-Rao lower bounds, the precision of glucose quantification reduced with the macromolecule basis set. Moreover, estimated glucose and taurine concentrations were shown to correlate for both analytical conditions. Thus, the quantification is not improved using the macromolecule basis set and may be more precise via detecting H1-α-glucose, which is free from spectral overlap. |
| 3867 | Computer 113
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2H MR measurement of amino acid uptake in glioblastoma multiforme |
| Samantha McClendon1, Kyu-Ho Song2, Xia Ge2, Joseph J.H. Ackerman2,3,4,5, Joel R. Garbow2,5, and Scott Beeman1 | ||
1School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States, 2Department of Radiology, Washington University in St.Louis, St.Louis, MO, United States, 3Department of Chemistry, Washington University in St.Louis, St.Louis, MO, United States, 4Department of Internal Medicine, Washington University in St.Louis, St.Louis, MO, United States, 5Alvin J. Siteman Cancer Center, Washington University School of Medicine in St.Louis, St.Louis, MO, United States |
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Keywords: Deuterium, Tumor, Amino Acid Glioblastoma (GBM) brain tumors are among the most lethal of all human cancers, with a median survival of ~15 months. Standard-of-care radiologic methods fail to detect infiltrating GBM, which leads to undertreatment. We report a 2H MR method to better resolve/characterize GBM based on its enhanced uptake of branched-chain amino acids (e.g., leucine). We measure relaxation time constants for deuterated leucine in agarose phantoms and show the ability to detect d10-leucine at ~200 mM in a 4x4x4 mm3 voxel in phantoms. Finally, we demonstrated 2H MR measurement of enhanced deuterated leucine uptake in a rodent model of GBM. |
| 3868 | Computer 114
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High spatiotemporal resolution whole-brain 2H MRS imaging (DMRSI) to differentiate grey and white matter metabolic dynamics in human brain at 7T |
| Xin Li1, Xiao-Hong Zhu1, Yudu Li2,3, Hannes M. Wiesner1, Zhi-Pei Liang2,4, and Wei Chen1 | ||
1Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 4Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States |
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Keywords: Deuterium, Brain Deuterium MRS imaging (DMRSI) is a promising tool to quantitatively study brain glucose metabolism, but it is challenging to simultaneously achieve high spatial and temporal resolution to capture metabolite dynamics in the human brain. In this study, we applied advanced RF head coil and post-processing techniques to perform high spatiotemporal-resolution (0.7cc nominal voxel and 2.5 min) DMRSI covering entire human brain at 7T with oral administration of deuterated glucose. The results show superior DMRSI sensitivity for mapping and differentiating the TCA cycle activity in grey and white matters. This capability is critical for disease applications including brain tumor. |
| 3869 | Computer 115
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Improving SNR in deuterium metabolic imaging of cancer: spatial denoising, joint spectral/metabolic-kinetics processing, and beyond |
| Elton Montrazi1, Qingjia Bao2, Ricardo Martinho3, Dana Peters4, Talia Harris1, Keren Sasson1, Lilach Agemy1, Avigdor Scherz1, and Lucio Frydman1 | ||
1Weizmann, Rehovot, Israel, 2Chinese Academy of Sciences, Wuhan, China, 3University of Twente, Enschede, Netherlands, 4Yale School of Medicine, New Haven, CT, United States |
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Keywords: Deuterium, Cancer, MRSI As DMI is a promising cancer screening approach but is challenged by low sensitivity, this study assesses multiple approaches to increase its SNR. Some of these –apodization, Compressed Sensing Multiplicative (CoSeM), Block-matching/3D filtering (BM3D)– involve image denoising. Others take into account the metabolic kinetics, and include it as dimension to be denoised. This can be achieved by smoothing the kinetic data axis via regularization, or by using subspace-constrained representations to concurrently solve for the 4D spatial/spectral/kinetics set. These methods can be further denoised –e.g., by CoSeM– leading to much clearer observations of lactate generated by in vivo tumor models. |
| 3870 | Computer 116
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Parallel Proton and Deuterium Metabolic Imaging |
| Yanning Liu1, Chathura Kumaragamage1, Terry W. Nixon1, Scott McIntyre1, Henk De Feyter1, and Robin A. de Graaf1 | ||
1Yale University, New Haven, CT, United States |
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Keywords: Deuterium, Deuterium, DMI 1H MRSI and DMI can provide crucial metabolic information to facilitate evaluations of neurological diseases. In this work, we applied interleaved 1H/2H methodology to achieve time-efficient, parallel 1H MRSI and DMI acquisition. We first describe the necessary sequence adjustments for both nuclei, including the re-optimization of the VAPOR water suppression scheme and the incorporation of a 2H equilibrium pulse. Phantoms were then used to demonstrate that high quality 1H MRSI and DMI data can be acquired in parallel. The interleaved 1H MRSI-DMI sequence is compatible with other interleaved MRI-DMI sequences and can be implemented for a complete MRI-DMI protocol. |
| 3871 | Computer 117
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Time-resolved deuterium metabolic imaging of the human brain at 7T |
| Minghao Zhang*1, Jabrane Karkouri*1, Daniel Atkinson1, and Christopher T. Rodgers1 | ||
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom |
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Keywords: Deuterium, Deuterium Deuterium metabolic imaging (DMI) is a new way to track brain metabolism. We present initial results from 3 volunteers scanned with a new 18-element 2H + 2-element 1H array coil on a Siemens 7T Terra scanner. We utilised our array’s high SNR to track metabolism by whole-brain 3D DMI after drinking 6,6’-[2H2]-glucose (Glc). Signals from HDO, Glc, Glx and Lac were visible over 2hrs at 5min temporal and 6.9mL spatial resolution. We also ran 2.9mL 3D DMI. We achieved HDO SNR of 43 in 13min, which compares favourably published SNR=13 in 10min at 9.4T1 and ~50 in 28min at 7T.2 |
| 3872 | Computer 118
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Direct comparison of deuterium 2H MRSI at 3T vs 7T |
| Jabrane Karkouri *1, Mary McLean *2, Minghao Zhang *1, Joshua D Kaggie2, Ashley Grimmer2, Alixander Khan2, Tomasz Matys2, Daniel Atkinson1, Ferdia Gallagher *2, and Christopher Rodgers *1 | ||
1University of Cambridge, Cambridge, United Kingdom, 2Radiology, University of Cambridge, Cambridge, United Kingdom |
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Keywords: Deuterium, Deuterium Deuterium metabolic imaging (DMI) is a new method to probe brain metabolism. Theory predicts higher SNR at higher field strength, but clinical translation is easier at lower field strength. We undertook 2H MRSI in 3 healthy volunteers at 3T and 7T sequentially. Acquisition was undertaken at baseline and after 11.1g oral D2O consumption. Data quality was acceptable in all scans. SNR was 3x higher at 7T, in agreement with theory. D2O cerebral uptake rate was similar between field strengths (0.13 min-1 at 3T vs 0.07 min-1 at 7T). |
| 3873 | Computer 119
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Deuterium oxide MRI to image the water inflow in the bovine lens of the eye |
| Xingzheng Pan1, Emily MacFarlane1, and Paul Donaldson1 | ||
1Physiology, University of Auckland, Auckland, New Zealand |
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Keywords: Deuterium, Aging, Human eye In the absence of a blood supply the lens operates an internal microcirculation to deliver nutrients, remove metabolic wastes, and controll the lens volume, which together to maintain the optical properties of the lens. While this microcirculation is generated by circulating fluxes of ions and water, visualising water flow throughout the whole lens and especially into the central of lens in real time has proven challenging. To address this, we developed and optimised new deuterium oxide (D2O) MRI protocols to image water flow within multiple organ-cultured bovine lenses that can be routinely performed using 3T clinical MRI. |
| 3874 | Computer 120
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Comparison the metabolism of [2H2]glucose,[2H7]glucose and [2H5]glucose in rat C6 glioma cells |
| Jiawen Yuan1,2, Yi Fang1, Qian Wan1, Chao Zou1,3, Xiaoliang Zhang4, Xin Liu1,3, Hairong Zheng1,3, and Ye Li1,3 | ||
1Lauterbur Imaging Research Center, Shenzhen Institute of Advanced Technology, Chinese Acamedy of Sciences, Shenzhen, China, 2Southern University of Science and Technology, Shenzhen, China, 3Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, 4Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States |
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Keywords: Deuterium, Deuterium Deuterium MRS(I) has emerged as a novel metabolic imaging method, which can effectively reflect the increased aerobic glycolysis of tumors. Recently, [2,3,4,6,6-2H5] glucose has been shown to be a cost-effective deuterium-labeled substrate for studying glycolysis in tumors. However, the effects of different deuterium-labeled substrates on metabolism require further comparison. In this study, we compared the differences between [6,6-2H2] glucose, [1,2,3,4,5,6,6’-2H7] glucose, and [2,3,4,6,6-2H5] glucose in rat C6 glioma cells. |
| 4014 | Computer 81
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Quantification of bilateral kidney oxygen consumption with MOTIVE-bSSFP |
| Rajiv S Deshpande1, Michael C Langham1, Cheng-Chieh Cheng1, and Felix W Wehrli1 | ||
1University of Pennsylvania, Philadelphia, PA, United States |
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Keywords: Oxygenation, Kidney, metabolic rate of oxygen Kidney oxygen consumption rate increases during the early stages of diabetes, ultimately leading to hypoxia of renal tissue. Thus, a reliable non-invasive approach to quantify kidney metabolism has significant clinical potential. Here, an approach to quantify the kidney oxygen utilization of both kidneys is reported. The method relies on the MOTIVE-bSSFP pulse sequence to measure SvO2 and blood flow rate in the inferior vena cava, above and below the branching of the renal vessels. Conservation of mass yields an expression to compute bilateral renal metabolic rate of oxygen. |
| 4015 | Computer 82
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Motion-corrected quantification of cerebral venous oxygenation in vulnerable populations: from neonates to older adults |
| Yifan Gou1, Christopher Golden2, Zixuan Lin3, Jennifer Shepard2, Aylin Tekes3, Zhiyi Hu3, Xin Li3, Kumiko Oishi4, Marilyn Albert5, Hanzhang Lu3, Peiying Liu3,6, and Dengrong Jiang3 | ||
1Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 2Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Center for Imaging Science, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, United States, 5Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 6Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States |
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Keywords: Oxygenation, Oxygenation Cerebral venous oxygenation (Yv) is a biomarker in various brain diseases such as hypoxic-ischemic-encephalopathy in neonates and Alzheimer's disease in the elderly. T2-Relaxation-Under-Spin-Tagging (TRUST) MRI is a widely used technique to measure global Yv level. However, subject motion during TRUST scan can cause considerable errors in Yv quantification. This work developed an automatic algorithm for motion-corrected quantification of Yv, which showed improved precision of Yv estimation in both neonates and elderly adults. |
| 4016 | Computer 83
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Deuterated trityl spin probe for in vivo pO2 imaging with improved precision using Time-Domain EPR |
| SHUN KISHIMOTO1, Nallathamby Devasahayam1, Kota Yamashita1, Kazumasa Horie1, Kazutoshi Yamamoto1, Jeffrey R Brender1, and Murali C Krishna1 | ||
1NCI, Bethesda, MD, United States |
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Keywords: Oxygenation, Cancer Due to the narrow linewidth and slower signal decay, it was expected that Ox071 is suitable for wide range pO2 estimation. In this work, we present our first 3D in vivo EPR oximetry using Ox071 in comparison with Ox063. EPR imaging of MIA Paca-2 tumor and healthy kidneys were performed on successive days by using either Ox071 or Ox063, resulting in similar spin density, pO2 maps, and pO2 histograms in the tumor regions and more homogeneous pO2 profile with Ox071 in kidney compared with Ox063. The result suggested that Ox071 is applicable for oximetry in tissue at higher pO2. |
| 4017 | Computer 84
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Venous blood oxygenation measurements using TRUST and T2-TRIR during hypoxic and hypercapnic gas challenges |
| Koen P.A. Baas1, Chau Vu2, Jian Shen2, Bram F. Coolen3, Gustav J. Strijkers3, John C. Wood2,4, and Aart J. Nederveen1 | ||
1Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, 2Biomedical Engineering, University of Southern California, Los Angeles, CA, United States, 3Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam, Netherlands, 4Division of Cardiology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, United States |
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Keywords: Oxygenation, Oxygenation TRUST and T2-TRIR can be used to measure venous blood oxygenation (Yv) and oxygen extraction fraction (OEF). T2-TRIR also offers simultaneous blood T1 (T1b) measurements for hematocrit calculation in lieu of invasive blood samples. Here, TRUST and T2-TRIR were compared across a broad Yv range using hypoxic and hypercapnic challenges in healthy volunteers, while T2-TRIR-derived hematocrit estimates were compared with venipuncture results. T2-TRIR- and TRUST-derived Yv and OEF values exhibited a small constant bias (-5.4±3.5% and 6.0±4.0% respectively, both p<0.01) across all stimuli. Hematocrit by venipuncture and from T1b were unbiased but had broad confidence intervals (1.7±6.3%, p=0.20). |
| 4018 | Computer 85
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Study of Oxidative Stress due to X-ray Irradiation in Mouse Brain using TOLD MRI Imaging |
| Raj Kumar Parajuli1, Megumi Ueno2, Saaya Suzuki1, Akira Sumiyoshi1, Takayuki Obata1, Ichio Aoki1, and Ken-ichiro Matsumoto2 | ||
1Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology (QST), Chiba, Japan, 2Department of Radiation Regulatory Science Research, National Institutes for Quantum Science and Technology (QST), Chiba, Japan |
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Keywords: Oxygenation, Brain, Oxidative stress, TOLD, X-ray irradiation This study aims to evaluate the metabolic changes caused on the brain tissues due to radiation exposure to healthy tissues while tumor treatment. The tissue oxidization and reduction mechanism represented by redox imaging could be a suitable index to evaluate in vivo oxidative stress in living animals that could evaluate metabolic damages due to irradiation. We adopted tissue oxygen level dependent (TOLD) MRI imaging to analyze TOLD signal for the control group mice and the irradiated mice. The result shows the distinct oxygen consumption levels in the control and the irradiated mice. |
| 4019 | Computer 86
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Oxygen extraction fraction (OEF) mapping by using multi-delay arterial spin labeling based on QSM+qBOLD |
| Xiaoyi Liu1, Yayan Yin1, Juan Wei2, and Jie Lu1 | ||
1Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China, Beijing, China, 2GE Healthcare, MR Research China, Beijing, Beijing, China |
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Keywords: Arterial spin labelling, Metabolism, oxygen extraction fraction We aimed to improve the accuracy of OEF mapping by using multi-delay arterial spin labeling based on quantitative susceptibility mapping plus quantitative blood oxygen level-dependent magnitude (QSM+qBOLD, or QQ). 3D multi-echo gradient-echo and ASL sequence were performed in 7 healthy subjects. ROIs analysis and paired t-test compared QQ with single-delay ASL and QQ with multi-delay ASL. QQ with multi-delay ASL shows smaller OEFs than QQ with single-delay ASL method. Corresponding OEFs were 38.9±3.4% and 39.6±3.4% (P<0.01) in gray matter, 39.7±2.9% and 40.2±2.9% in whole brain(P<0.01), respectively. Our study suggests that QQ with multi-delay ASL provides more accurate OEF than QQ with single-delay ASL, which may have potential in the use of clinical diseases. |
| 4020 | Computer 87
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Zero-echo time (ZTE) pulse sequence enables EEG-fMRI with suppression of susceptibility artifacts. |
| Ayako Imamura1,2,3, Rikita Araki4, Yukari Takahashi3, Koichi Miyatake2, Fusao Kato3, Sakiko Honjoh2, and Tomokazu Tsurugizawa3,5,6 | ||
1Ph. D. Program in Humanics, University of Tsukuba, Tsukuba, Japan, 2International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan, 3Department of Neuroscience, The Jikei University School of Medicine, Tokyo, Japan, 4Bruker Japan K.K., Yokohama, Japan, 5Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, 6Faculty of Engineering,, University of Tsukuba, Tsukuba, Japan |
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Keywords: fMRI, fMRI Simultaneous recording of fMRI and EEG is a promising approach to realize functional brain imaging with high temporal and spatial resolution. However, using standard echo planar imaging in conventional fMRI studies, implantation of electrodes on the cortical surface induces strong magnetic susceptibility artifacts in fMRI images. The zero-echo time (ZTE) sequences show a remarkable reduction in sensitivity to magnetic susceptibility artifacts and motion-derived artifacts. In this study, we showed that the ZTE sequence suppressed the susceptibility artifact by electrodes and air in the ear canal in mice. Furthermore, ZTE showed the typical functional connectivity in the mice at resting state. |
| 4021 | Computer 88
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Pharmacological Inactivation of the Inhibitory Zona Incerta Decreased Resting-state Functional MRI Connectivity |
| Junjian Wen1,2, Xunda Wang1,2, Teng Ma1,2,3, Linshan Xie1,2, Alex T. L. Leong1,2, and Ed X. Wu1,2,4 | ||
1Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, 2Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 3Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong SAR, China, 4School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China |
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Keywords: fMRI (resting state), Neuroscience In the recent decade, resting-state functional MRI (rsfMRI) has emerged as the most invaluable, non-invasive imaging technique to map long-range, brain-wide functional connectivity networks. Despite the enormous potential inherent in this technique, our present knowledge of the neural underpinnings of rsfMRI connectivity remains generally incomplete given the lack of studies examining the role of the inhibitory neural population, which is the counterpart of the excitatory neurons. In this study, we directly examine the role of zona incerta, which is one of the major source of inhibitory drive to the cortex. |
| 4022 | Computer 89
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Whole-brain fMRI study of mice under medetomidine/ketamine anesthesia to identify brain regions activated by musk odors |
| Sosuke Yoshinaga1, Yumiko Tsubakihara1, Takayuki Fukumoto1, Shotaro Maita1, Mitsuhiro Takeda1, and Hiroaki Terasawa1 | ||
1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan |
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Keywords: New Devices, Preclinical Muscone, a major component of musk odor, attracts male mice. The odor-evoked behaviors are mediated by neural circuits activated by the stimulation. We have been working on whole-brain BOLD fMRI studies of mice, using a method that employs periodic odor stimulation and independent component analysis. In this study, we investigated the brain regions activated by muscone in mice under medetomidine and low-dose ketamine anesthesia. Ketamine reportedly exhibits disinhibition of glutamate signaling at a low dose. As the result, we identified numerous muscone-evoked activated regions located in the olfactory pathways and higher-order regions in the cerebrum. |
| 4023 | Computer 90
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Behavioural Relevance modulates BOLD-fMRI responses in the rat Visual Cortex |
| Ana Mafalda Valente1, Rita Gil1, and Noam Shemesh1 | ||
1Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal |
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Keywords: fMRI, Multimodal, NEURO Neuronal responses are shaped by experiences. Plasticity can occur at single neuron level or at the full population level. Here, we established a novel behavioural task requiring rats to distinguish between continuous and flickering lights. We then performed fMRI in trained vs naive animals and investigated BOLD-fMRI responses along the visual pathway. When light flashes become meaningful in trained animals, the BOLD activation patterns are significantly modulated compared to naive counterparts, in particular in higher visual cortex and associative areas. BOLD-fMRI signals are thus capable of deciphering plasticity arising from strong associations with actions and rewards. |
| 4024 | Computer 91
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An improved data acquisition for robust oxygen extraction fraction (OEF) mapping using an integrative model of QSM and qBOLD (QSM+qBOLD=QQ) |
| Junghun Cho1, Pascal Spincemaille2, Thanh D. Nguyen 2, and Yi Wang2 | ||
1Biomedical Engineering, SUNY Buffalo, Buffalo, NY, United States, 2Weill Cornell Medicine, New York, NY, United States |
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Keywords: Oxygenation, Quantitative Imaging Oxygen extraction fraction (OEF) is critical to evaluate brain tissue viability and function in neurologic disorders. An integrated model of QSM and qBOLD (QSM+qBOLD or QQ) has been developed to map OEF utilizing a routine multi-echo gradient echo (mGRE) acquisition without impractical vascular challenges. This study proposes a novel mGRE acquisition with logarithmic echo spacing that acquires more data points in short echo time regime, which is critical to decouple the model parameters in QQ. The proposed novel mGRE provided more accurate OEF in two simulations, compared to the conventional mGRE. |
| 4025 | Computer 92
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Uncertainties in baseline cerebral oxidative metabolism mapping by gas-free and dual-calibrated fMRI: a simulation-based comparison |
| Xiaole Zhong1,2 and J. Jean Chen1,2,3 | ||
1Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute, Baycrest Hospital, Toronto, ON, Canada, 3Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada |
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Keywords: fMRI, Metabolism Calibrated BOLD fMRI is becoming a method of choice in assessing baseline cerebral oxidative metabolism (CMRO2), with gas-free calibrated fMRI being an non-invasive alternative to the more established gas-calibrated fMRI methods. However, the relative repeatabilities of these two approaches are unknown, each depending on a unique set of input measurements. This study uses analytical simulations to investigate the sensitivity of baseline OEF and CMRO2 estimates to the measured inputs of each method. Our results suggest that gas-free calibrated fMRI is substantially less sensitive to input variations than gas-calibrated fMRI, demonstrating the potential for simulation-informed methodological selection. |
| 4026 | Computer 93
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Default Mode Network is Not Related to Similarly Vigilance Dependent Slow Rhythms |
| Vahid Khalilzad Sharghi1, Eric Maltbie1, Wen-Ju Pan1, Shella Keilholz1, and Kaundinya Gopinath1 | ||
1Emory University, Atlanta, GA, United States |
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Keywords: fMRI (resting state), Brain Connectivity Several studies point to brain slow rhythms as the basis of rsfMRI signal. We recently reported that only vigilance/arousal dependent components of fMRI signal that are not specific to brain function networks (BFNs) decrease after suppression of slow rhythms, while BFNs increase in apparent strength. Default mode network (DMN) is a BFN that exhibits similar dependence on vigilance as slow rhythms. In this study, we examined the effects of slow rhythm suppression on the integrity of DMN. Our results show that DMN is not related to these rhythms and behaves just like other BFNs upon their suppression. |
| 4027 | Computer 94
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Computing hemodynamic point-spread functions with biophysical simulations of microvascular networks: effects of trans-laminar capillaries |
| Grant Hartung1,2, Avery J. L. Berman1,2, Divya Varadarajan1,2, Jingyuan Chen1,2, and Jonathan R. Polimeni1,2,3 | ||
1Athinoula A. Martinos Center For Biomedical Imaging, MGH, Charlestown, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States |
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Keywords: fMRI, Blood vessels, High-Resolution fMRI, Biophysical Simulation Here we attempted to estimate a “point-spread function” of blood flow and oxygenation in the cerebral cortex through biophysical simulations based on a reconstructed vascular anatomical network. We stimulated individual pre-capillary arterioles and computed the downstream capillary flow and oxygenation based on fluid dynamics and oxygen transport through blood and tissue. We quantified this spread in the directions radial and tangential to the cortex. While several biases in spread were observed, we found a roughly 400 μm spread in the radial direction and generally narrower spread in the tangential direction, although both varied with cortical depth. |
| 4028 | Computer 95
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BOLDSwimSuite: A Python-based tool suite for numerical simulations of transverse relaxation in the presence of diverse field perturbers |
| Jacob Chaussé1, Avery J. L. Berman2,3, and J. Jean Chen1,4 | ||
1Rotman Research Institute, North York, ON, Canada, 2Department of Physics, Carleton University, Ottawa, ON, Canada, 3University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada, 4Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Keywords: Simulations, Software Tools Numerical simulations are valuable tools for understanding the transverse relaxation process, but their use is impeded by computational complexities and a lack of standard in simulation pipelines. We present a new software suite (named BOLDSwimSuite) to address these challenges, making numerical simulations accessible to a wider community of researchers. Among its many features, this toolbox is able to accommodate arbitrary magnetic-field perturbers as well as simulate different MRI sequences. This toolbox is useful for investigating BOLD fMRI contrast and MR vascular fingerprinting among other applications. |
| 4029 | Computer 96
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Development of a quantitative BOLD phantom for validation of acquisition strategies. |
| Ahlam Alzaidi1,2, Rafal Panek3, and Nicholas P Blockley1 | ||
1School of Life Sciences, University of Nottingham, Nottingham, United Kingdom, 2Radiology Department, Taif University, Taif, Saudi Arabia, 3Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom |
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Keywords: Relaxometry, Phantoms A phantom to produce R2' (reversible transverse relaxation rate) contrast was developed by inducing subvoxel magnetic susceptibility variations that mimic the quantitative Blood Oxygenation Level Dependant (qBOLD) MRI signal. Microscopic glass bubbles were used for this purpose and offer a cheaper option for making large volume phantoms than existing phantoms that use precision polystyrene microspheres. A linear relationship between R2' and the glass bubble volume fraction was found. Comparisons of multiparametric qBOLD acquisitions between two MR vendors were also made. In the future, phantoms such as this could facilitate quality assurance for qBOLD acquisition strategies and assist with multicentre harmonization. |
| 4030 | Computer 97
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Simulating BOLD fMRI transverse relaxation at 3 T: How accurate is the infinite cylinder model of blood vessels? |
| Avery J.L. Berman1,2, Jacob Chausse3, Grant Hartung4,5, Jonathan R. Polimeni4,5,6, and J. Jean Chen3,7 | ||
1Department of Physics, Carleton University, Ottawa, ON, Canada, 2University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada, 3Rotman Research Institute, Baycrest Health Sciences, North York, ON, Canada, 4Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 5Department of Radiology, Harvard Medical School, Boston, MA, United States, 6Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 7Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada |
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Keywords: Simulations, fMRI Simulations of the BOLD signal have provided invaluable insights into the biophysical underpinnings of BOLD contrast. Typically, infinite cylinders are used to represent the vasculature, although, in reality the vasculature is much more complex. In this study, we compared several biophysical modelling techniques for simulating the BOLD effect, including using Vascular Anatomical Networks (VANs) to model the capillary bed with realistic geometry. We found the majority of the different simulation approaches produced relatively consistent results with each other. The VAN simulations were consistent with the infinite cylinders, suggesting that infinite cylinders are a reasonable approximation to more realistic vascular models. |
| 4149 | Computer 61
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Measuring cellular-interstitial water exchange time in patients with head and neck cancer using time-dependent diffusion experiments |
| Eddy Solomon1, Gregory Lemberskiy2, Steven Baete2, Kenneth Hu3, Dariya Malyarenko4, Scott Swanson4, Amita Shukla-Dave5, Stephen E Russek6, Elcin Zan2, and Sungheon Gene Kim1 | ||
1Radiology, Weill Cornell Medicine, New York, NY, United States, 2Radiology, New York University, New York, NY, United States, 3Radiation Oncology, New York University, New York, NY, United States, 4Radiology, University of Michigan, Ann Arbor, MI, United States, 5Medical Physics and Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 6National Institute of Standards and Technology, Boulder, CO, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Cancer Cellular-interstitial water exchange time has been suggested to be associated with a number of important cellular properties such as membrane permeability, tumor aggressiveness and treatment response. In this study we investigated the reliability of measuring water exchange times based on diffusivity and diffusional kurtosis at long diffusion times. We used two well-established diffusion phantoms and found that diffusion and kurtosis show stable values over a wide range of diffusion times. In head and neck cancer patients, we found that the Kärger model is a valid model for measuring water exchange time in metastatic lymph node voxels. |
| 4150 | Computer 62
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Preliminary study of DCE-MRI combined with DWI in discriminating tumor deposits from lymph node metastasis in rectal cancer |
| WEN JUN HU1, Anliang Chen1, and AIlian Liu1 | ||
1The First Affiliated Hospital of Dalian Medical University, Dalian, China |
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Keywords: Diffusion/other diffusion imaging techniques, Cancer Tumor deposits (TDs) in rectal cancer have been shown to be an important marker of poor prognosis. Although very similar to lymph node metastasis (LNMs), TDs have unique features in terms of biology and outcome, suggesting that distinguishing between these two entities may be of great importance. Results of this study indicate DWI and DCE-MRI can effectively differentiate TDs and LNMs in rectal cancer, Combination of DWI and DCE-MRI imaging may serve as an effective noninvasive method for differentiation of TDs from LNMs in rectal cancer. |
| 4151 | Computer 63
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Effective axon radii across the human corpus callosum for a group of subjects: comparability between MRI and histology |
| Laurin Mordhorst1, Mohammad Ashtarayeh1, Maria Morozova2,3, Luke J. J Edwards2, Carsten Jäger2, Henriette Rusch3, Tobias Streubel1, Nikolaus Weiskopf2,4, Markus Morawski2,3, and Siawoosh Mohammadi1,2 | ||
1Institute of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 3Paul Flechsig Institute - Center of Neuropathology and Brain Research, Medical Faculty University of Leipzig, Leipzig, Germany, 4Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany, Leipzig, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Validation, Histology Connectome Axon radius Deep learning Robust MRI-based axon radius estimation is sensitive to a tail-weighted estimate of the ensemble-average axon radius, i.e., the effective axon radius ($$$r_{eff}$$$). Existing validation studies of $$$r_{eff}$$$ in the human brain are confounded because the histological gold standard cannot representatively sample the tail of the axon radii distribution due to limited sample size. We compare in vivo, MRI-based $$$r_{eff}$$$ of five healthy adults against a representative histological gold standard of three donors in the human corpus callosum and demonstrate that spatial patterns of the $$$r_{eff}$$$ along the anterior-posterior axis agree between in vivo MRI and ex vivo histology. |
| 4152 | Computer 64
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Aquaporin4 inhibitor alters the apparent diffusion coefficients in mouse brain |
| Tomokazu Tsurugizawa1,2, Cuong Pham3, Anna Deàs Just3, Benjamin Le Gac3, Dongdong Li3, Bruno Cauli3, and Yuji Komaki4 | ||
1National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, 2Faculty of Engineering, University of Tsukuba, Tsukuba, Japan, 3Sorbonne University, Paris, France, 4Central Institute for Experimental Animals, Kawasaki, Japan |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques The glymphatic system seems to be involved to protect the brain pathologies like Alzheimer’s disease, by the clearance of brain waste1. A previous study showed the apparent diffusion coefficients (ADC) in several brain regions were increased by aquaporin 4 (AQP4) inhibitor2. However, the time course of ADC change has not been investigated. In this study, we showed the time course of ADC change in multiple mouse brain regions following injection of the TGN020 and the effect of TGN020 on volume-dependent intrinsic optical signals in brain slices. |
| 4153 | Computer 65
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Evaluating histotripsy treatment dosage in the brain using MRI |
| Dinank Gupta1, Tarana P Kaovasia1, Dave Choi1, Steven P Allen2, Timothy L Hall1, Zhen Xu1, and Douglas C Noll1 | ||
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, 2Brigham Young University, Provo, UT, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Focused Ultrasound, Histotripsy Histotripsy is a non-invasive, non-thermal focused ultrasound ablation method that mechanically breaks down the target tissue into acellular debris and has shown promising results for brain surgery. Quantifying histotripsy treatment dosage is required to avoid over/under-treatment of the target region. In this work, we assess whether T1, T2 and ADC maps can be utilized to quantify the ablation effect generated by varying histotripsy dosage post-treatment using an ex-vivo bovine brain. We show that only the ADC map is able to visualize the histotripsy ablation. Increasing histotripsy dosage results in increasing ADC. |
| 4154 | Computer 66
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Revealing signatures of demyelination and axonal loss in white matter extra-axonal space using time dependent diffusion |
| Ricardo Coronado-Leija1, Hong-Hsi Lee2, Els Fieremans1, and Dmitry S Novikov1 | ||
1Radiology, NYU Grossman School of Medicine, New York, NY, United States, 2Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States |
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Keywords: Microstructure, Simulations In this work, we relate a specific feature of brain microstructure, the axon packing correlation length $$$l_c$$$, with parameters of time-dependent diffusion $$$D(t)$$$ obtained from Monte Carlo simulations. We observe that diffusion correlation length estimated from $$$D(t)$$$ shows good correspondence with $$$l_c$$$ estimated from geometries of packed disks with several densities, simple models for axon loss and demyelination, as well as for realistic substrates obtained from segmented electron microscopy. |
| 4155 | Computer 67
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Probing gray matter microstructure with diffusion MRI in preclinical Alzheimer’s disease: A comparison of methods |
| Teresa Scheidt1, Markus Nilsson1, Danielle van Westen1,2, Erik Stomrud3,4, Oskar Hansson3,4, and Nicola Spotorno3 | ||
1Diagnostic Radiology, Department of Clinical Sciences, Lund University, Lund, Sweden, 2Image and Function, Skåne University Hospital, Lund, Sweden, 3Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Lund, Sweden, 4Memory Clinic, Skåne University Hospital, Malmö, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Alzheimer's Disease Gray matter microstructural changes appear prior to macrostructural changes in Alzheimer’s disease, these changes can be probed by diffusion MRI. However, different methods can be used to extract metrics in the thin cortical ribbon. The influence of the choice of method on the results has not been investigated yet. In this work, two different methods of extracting diffusion metrics in the cortex are compared, a surface-based approach and gray matter based spatial statistics (GBSS). We improve upon GBSS and show it now yields comparable results to a surface-based method. |
| 4156 | Computer 68
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Time-dependent diffusion MRI study of chemoradiation treatment response in patients with HPV positive oropharyngeal carcinoma |
| Eddy Solomon1, Steven H. Baete2, Joseph K. Kim3, Moses Tam3, Zujun Li4, Kenneth Hu3, Elcin Zan2, and Sungheon Gene Kim1 | ||
1Radiology, Weill Cornell Medical College, New York, NY, United States, 2Radiology, New York University Grossman School of Medicine, New York, NY, United States, 3Radiation Oncology, New York University Grossman School of Medicine, New York, NY, United States, 4Medical Oncology, New York University Grossman School of Medicine, New York, NY, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Treatment In this study, we evaluated the time-dependence of diffusivity and kurtosis in HPV-positive oropharyngeal squamous cell carcinoma patients before and during chemo-radiation treatment, as part of a study for adaptive de-escalation of the therapy. The non-deescalated patients with less than 40% nodal shrinkage had significantly higher diffusivity and lower kurtosis at pre-treatment than the de-escalated patients with more than 40% nodal volume shrinkage. The water exchange times were longer in the de-escalated patients than in the non-deescalated patients, although not significant. The prognostic accuracy of the pre-treatment imaging parameters was between 0.7 and 0.85. |
| 4157 | Computer 69
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Multidimensional diffusion MRI for monitoring radiotherapy response in human prostate cancer xenografts in mice: A longitudinal pilot study |
| Filip Szczepankiewicz1, Marcella Safi2, Crister Ceberg1, Michael Gottschalk3, Evangelia Sereti4, Anders Bjartell4, Oskar Vilhelmsson Timmermand5, Linda Knutsson1,6, Sven-Erik Strand1,7, and Joanna Strand2,7 | ||
1Medical Radiation Physics, Lund University, Lund, Sweden, 2Hematology, Oncology, Radiation Physics, Lund University, Lund, Sweden, 3Lund University Bioimaging Centre, Lund University, Lund, Sweden, 4Translational Medicine, Lund University, Lund, Sweden, 5King's College London, London, United Kingdom, 6F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 7Dept of Oncology, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Prostate Cancer, Multidimensional MRI, Radiotherapy We use multidimensional diffusion MRI to monitor longitudinal effect of external radiotherapy in human prostate cancers in mice. The measured dimensions are “diffusion time” and “shape of the b-tensor,” enabling a probe of tissue heterogeneity, microscopic anisotropy and restriction sizes. We show that the diffusivity is highly time dependent in all tumors, and that it is significantly altered by radiotherapy, already within 1-15 days of treatment. The largest effect is seen for the diffusivity and its time dependence, but the isotropic diffusional variance is also impacted. Throughout, histology is used qualitatively to provide plausible interpretations to the observations. |
| 4158 | Computer 70
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Detection of multiple sclerosis by extraction of quantitative parameters of brain tissue microstructure in ex-vivo cerebellum samples |
| Gopal Varma1, Aaron K Grant1, Olivier M Girard2, Guillaume Duhamel2, and David C Alsop1 | ||
1Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2CNRS, CRMBM, Aix-Marseille Univ, Marseille, France |
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Keywords: Microstructure, Quantitative Imaging Extraction of quantitative parameters of brain tissue microstructure is possible with DTI, inhomogeneous MT (ihMT), and MWF MRI. We examine the ability of the parameters from these techniques to distinguish ex-vivo specimens of the cerebellum from donors with MS relative to non-MS tissue. Significant differences were found for DTI and MT/ihMT metrics in WM, but only for MT/ihMT in GM. Differences between quantitative MT parameters from fits to ihMT data were not significant. |
| 4159 | Computer 71
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Longitudinal assessment of MD and FA in four whole human brains using the DTI model |
| Nina Lüthi1, Francisco J. Fritz1, Björn Fricke1, Tobias Streubel1, Herbert Mushumba2, Klaus Püschel2, and Siawoosh Mohammadi1,3 | ||
1Department of Systems Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Institute of Legal Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany, 3Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Ex-Vivo Applications, fixation, PFA, in-situ MRI, whole human brain We investigated the longitudinal fixation effect of 4% paraformaldehyde and phosphate-buffered saline on diffusion imaging-derived mean diffusivity (MD) and fractional anisotropy (FA) across deep gray, cortical gray and white matter in human brains using suboptimal and optimal diffusion protocols with varying maximal b-values.We had two main findings: (1) a suboptimal diffusion protocol led to increased bias in the FA and MD up to 36.26% and 38.11%, the same trend was also observed for the across-brain variation; (2) MD changed by a maximum of 26.42% within the first 14 days in fixative and saturated afterward, whereas FA remained almost constant. |
| 4160 | Computer 72
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White matter microstructure mapping using diffusion-only or diffusion-relaxation: protocol design and comparison of accuracy and precision |
| Ying Liao1, Santiago Coelho1, Filip Szczepankiewicz2, Dmitry S. Novikov1, and Els Fieremans1 | ||
1Radiology, NYU School of Medicine, NEW YORK, NY, United States, 2Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques Combining diffusion and relaxation is promising in probing the tissue microstructure in brain white matter. We designed an optimal diffusion-relaxation protocol with varying b-values, b-tensor shapes and echo times by minimizing the error of parameter estimation. We compared the Standard Model parameters estimated by diffusion-relaxation and diffusion-only data using sensitivity-specificity matrices and test-retest data on volunteers and found excellent agreement. With a comprehensive acquisition protocol, the Standard Model can accurately capture the signal content in white matter with diffusion MRI. |
| 4161 | Computer 73
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Age-related time-dependent diffusivity changes within healthy human prostate |
| Xiao Ma1, Peter Seres1, Adam Kinnaird2, Christopher Fung3, Thorsten Feiweier4, and Christian Beaulieu1 | ||
1Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, 2Department of Urology, University of Alberta, Edmonton, AB, Canada, 3Department of Radiology, University of Alberta, Edmonton, AB, Canada, 4Siemens healthineers, Erlangen, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Prostate Diffusion MRI is used daily in prostate cancer diagnosis. Modification of the diffusion time can probe alterations in prostate microstructure dimensions that may occur with aging or cancer. The mean diffusivity (MD) difference between ‘long’ diffusion time stimulated echo acquisition mode (STEAM) and ‘short’ diffusion time oscillating gradient spin echo (OGSE), and between STEAM and ‘medium’ diffusion time pulsed gradient spin echo (PGSE) showed significant positive linear correlation versus age in peripheral zone of healthy adult prostate (n=15); however, this correlation was not identified in the central gland. Diffusion time sensitivity could reveal age-related prostate tissue microstructural remodeling. |
| 4162 | Computer 74
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Comparison of Intra-Hippocampal Fiber Tracks and Connectomes between Alzheimer’s Patients and Age-Matched Healthy Controls |
| Devon Karl Overson1,2, Yixin Ma3, Trong-Kha Truong1,2,4, David J. Madden1,5, Jeffrey R. Petrella1,2,4, and Allen Song1,2,4 | ||
1Duke-UNC Brain Imaging & Analysis Center, Duke University, Durham, NC, United States, 2Duke Medical Physics Graduate Program, Duke University, Durham, NC, United States, 3Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Department of Radiology, Duke University, Durham, NC, United States, 5Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States |
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Keywords: Tractography & Fibre Modelling, Alzheimer's Disease, DTI, Hippocampus, Hippocampal Subfield, Connectome Changes in intra-hippocampal connectivity caused by early neurodegeneration in specific hippocampal subfields could serve as a biomarker for the early diagnosis of Alzheimer’s disease (AD), years before the onset of symptoms, when the neurodegeneration may still be reversed by treatments. Here, we use high-resolution DTI to compare intra-hippocampal fiber tracks and connectomes across different hippocampal subfields in AD patients and age-matched healthy controls. A significant (p < 0.01) decrease in number of streamlines was found in the AD group compared to the control group for four pairs of subfields, independently of a reduced hippocampal volume affecting nearly all subfields. |
| 4163 | Computer 75
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Does intravoxel incoherent motion MRI measure tumor perfusion? A comparison with DCE-MRI in patients with breast cancer. |
| Zyad M. Almutlaq1,2, Sarah E. Bacon3, Daniel J. Wilson3, Nisha Sharma4, and David L. Buckley1 | ||
1Biomedical Imaging, University of Leeds, Leeds, United Kingdom, 2Radiological Sciences Department, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia, 3Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom, 4Department of Radiology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom |
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Keywords: Diffusion/other diffusion imaging techniques, DSC & DCE Perfusion, IVIM DCE-MRI can provide quantitative estimates of perfusion-related parameters in tumors, such as blood flow and blood volume fraction. It has also been proposed that IVIM MRI can be used to characterize perfusion in addition to microstructure. This proposal remains controversial and requires further investigation. In this study, we investigate the relationship between perfusion-related parameters measured by IVIM and DCE-MRI in a cohort of patients with breast cancer imaged before and after one and two cycles of neoadjuvant chemotherapy. |
| 4164 | Computer 76
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Feasibility of spiral diffusion imaging on a clinical 3T MR system |
| Lars Kasper1, Zhe Wu1, Alexander Jaffray1,2, Sriranga Kashyap1, and Kamil Uludag1,3,4 | ||
1BRAIN-TO Lab, Techna Institute, University Health Network, Toronto, ON, Canada, 2UBC MRI Research Centre, Vancouver, BC, Canada, 3Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 4Center for Neuroscience Imaging Research, Institute for Basic Science & Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion Tensor Imaging, Spiral DWI Spiral diffusion imaging has been shown to provide substantial SNR advantages (>50%) over state-of-the-art echo-planar imaging, due to the attainable shorter echo times. We investigate the feasibility of this approach on a standard 3T MR system without additional instrumentation. All tools for successful implementation are freely made available, i.e., the characterization measurement for the gradient system using a standard phantom, and an open-source, fast image reconstruction suite in Julia correcting for gradient imperfections, eddy currents, and static B0 off-resonance. We show that this low-cost, accessible solution provides high-resolution diffusion images (1.1mm) in-vivo with reduced geometric distortion and improved quantitative maps. |
| 4165 | Computer 77
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Tractography of the subcortical U-fibers using a position-dependent maximum angle |
| Nicolas Delinte1,2, Quentin Dessain1, Manon Dausort1, Colin Vanden Bulcke1,2, and Benoit Macq1 | ||
1ICTEAM, UCLouvain, Louvain-la-Neuve, Belgium, 2IoNS, UCLouvain, Louvain-la-Neuve, Belgium |
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Keywords: Brain Connectivity, Tractography & Fibre Modelling Short association fibers in the subcortical white matter, also known as U-fibers, represent the connections between neighboring gyri. Due to the geometry of the cortical folds and the sharp turns along the cortical surface, tractography of U-fibers remains a challenge since increasing the maximum angle between tractography steps also increases the occurence of false positive streamlines. We propose to replace the fixed maximum angle value in tractography algorithms by an angular map, allowing higher angles at the interface between grey and white matter. This enables a more accurate tracking of U-fibers, while keeping a low number of false positive streamlines. |
| 4166 | Computer 78
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Validation of Intravoxel Incoherent Motion (IVIM) Methods in the Liver using the NIST Diffusion Phantom |
| Marissa Brown1, Juan Vasquez2, Geoffrey Clarke1, and John Blangero3 | ||
1Radiological Sciences, University of Texas Health Science Center San Antonio, San Antonio, TX, United States, 2School of Medicine, Indiana University, Indianapolis, IN, United States, 3South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Brownsville, TX, United States |
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Keywords: Phantoms, Diffusion/other diffusion imaging techniques, intravoxel incoherent motion, liver, fibrosis Intravoxel incoherent motion (IVIM) MRI is used to measure quantitative biomarkers of liver fibrosis, but accuracy and reproducibility of various methods requires validation. Six IVIM methods with different acquisition parameters (motion control techniques, b-values, single shot EPI v. SMS) were assessed using the NIST diffusion phantom. The phantom measurements met conformance standards for percent apparent diffusion coefficient (ADC) bias and ADC linearity using a protocol modified for liver MRI. Given that no standard IVIM liver phantom has been developed, the NIST diffusion phantom is shown to work well for validation of liver IVIM acquisitions. |
| 4167 | Computer 81
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Study of QSM’s contrast sources in the brain using Electron Paramagnetic Resonance |
| Fábio Seiji Otsuka1, Maria Concepción García Otaduy2, and Carlos Ernesto Garrido Salmon1 | ||
1InbrainLab, University of São Paulo, Ribeirão Preto, Brazil, 2LIM44, University of São Paulo, São Paulo, Brazil |
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Keywords: Electromagnetic Tissue Properties, Quantitative Susceptibility mapping QSM is a promising MRI techniques that enables the assessment of magnetic properties of tissue. However, its underlying biophyisical source of contrast is still unknown. It has been shown that iron is well correlated in the basal ganglia, however this hasn't been investigates for other regions. Furthermore, iron can be presented in different forms in the brain, each one having different functions and properties. This work aims to assess the composition of brain structures regarding its paramagnetic ions' and total metal content, comparing their concentrations with magnetic susceptibility assessed by QSM |
| 4168 | Computer 82
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Successful generalization for data with higher or lower resolution than training data resolution in deep learning powered QSM reconstruction |
| Sooyeon Ji1, Juhyung Park1, Hyeong-Geol Shin2,3, Joonhyeok Yoon1, Minjun Kim1, and Jongho Lee1 | ||
1Department of Electrical Computer Engineering, Seoul National University, Seoul, Korea, Republic of, 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States |
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Keywords: Susceptibility, Data Processing A pipeline to reconstruct multiple resolution QSM data using a QSM network trained at a single resolution is proposed. The local field map is re-sampled multiple times in different spatial locations, and the re-sampled local field maps are used to reconstruct QSM maps at training data resolution. The reconstructed maps are then combined, and corrected for using a procedure named “dipole compensation”. When compared to two scenarios to reconstruct different resolution data using network trained at a single resolution, the proposed pipeline demonstrated the best performance both qualitatively and quantitatively. |
| 4169 | Computer 83
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Relationship Between Fractional Anisotropy and Negative Susceptibility from Single-orientation Magnetic Susceptibility Separation |
| Hirohito Kan1, Yuto Uchida2, Yoshino Ueki3, and Harumasa Kasai4 | ||
1Department of Integrated Health Scieneces, Nagoya University Graduate School of Medicine, Nagoya, Japan, 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Rehabilitation Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, 4Department of Radiology, Nagoya City University Hospital, Nagoya, Japan |
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Keywords: Electromagnetic Tissue Properties, White Matter The magnetic source separation method can estimate contributions of diamagnetic myelin and paramagnetic iron in the white matter using solely gradient-echo data in white matter. This study determined the relationship between negative susceptibility (χ-) and fractional anisotropy as a myelin-sensitive biomarker and compared with the conventional susceptibility (χ) in young healthy volunteers. There was a significant negative correlation between the χ- and FA. In contrast, the conventional χ has a weaker correlation to the FA than the χ- result. However, the χ- in white matter represented the non-monotonic fiber orientation dependence on the B0 field. |
| 4170 | Computer 84
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Feasibility and Preliminary Evaluation of Breath Hold and Free Breathing Quantitative Susceptibility Mapping of the Liver |
| Julia V Velikina1, Collin J Buelo1,2, Yan Wu3, Marcus T Alley3, Moniba Nazeef4, Michael Jeng3, Alexey A Samsonov1, Scott B Reeder1,2,4,5,6, Shreyas S Vasanawala3, and Diego Hernando1,2 | ||
1Radiology, University of Wisconsin - Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 3Stanford University, Stanford, CA, United States, 4Medicine, University of Wisconsin - Madison, Madison, WI, United States, 5Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States, 6Emergency Medicine, University of Wisconsin - Madison, Madison, WI, United States |
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Keywords: Susceptibility, Liver Quantitative susceptibility mapping (QSM) is a promising non-invasive technique for quantification of liver iron concentration. Abdominal QSM typically requires a breath-hold acquisition since respiration induces liver motion, which leads to blurring artifacts. However, some patients have trouble even with a short breath-hold, which necessitates development of free-breathing approaches. In this work, we report initial results on the feasibility of using the modified “butterfly” navigator approach in multi-echo imaging in conjunction with compressed sensing reconstruction to enable free-breathing liver QSM. |
| 4171 | Computer 85
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Deep Fourier-Space Inversion |
| Mathias Lambert1,2,3, Javier Silva1,2,3, Carlos Milovic4, and Cristian Tejos1,2,3 | ||
1Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Millennium Institute for Intelligent Healthcare Engineering (iHEALTH), Santiago, Chile, 4School of Electrical Engineering, Pontificia Universidad Católica de Valpaiso, Valparaiso, Chile |
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Keywords: Susceptibility, Quantitative Susceptibility mapping Guiding the network architecture to learn to apply the kernel inversely in Fourier space allows training to be less prone to overfitting. Using simulated images from a single brain image, it is possible to satisfactorily reconstruct a susceptibility map of the abdomen. By having as input the Fourier space of the local field and the kernel of the dipole, the network learned to reduce the noise, to divide the data of the local field by the kernel where possible and to recover the data in the magic cone. |
| 4172 | Computer 86
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Subject-specific χ-separation method: the effect of introducing a personalised relaxometric constant Dr |
| Elena Grosso1, Antonio Ricciardi2, Egidio D'Angelo1,3, Fulvia Palesi1, and Claudia AM Gandini Wheeler-Kingshott1,2,3 | ||
1Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy, 2NMR Research Unit, Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Queen Square Institute of Neurology, University College London (UCL), London, United Kingdom, 3Brain Connectivity Centre Research Unit, IRCCS Mondino Foundation, Pavia, Italy |
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Keywords: Susceptibility, Modelling, Brain χ-separation is a recently proposed biophysical model to separate the χ-positive and χ-negative contribution of magnetic susceptibility sources in the brain. Such a model relies on assuming a certain relaxometric constant (Dr) calculated as the mean of a group of healthy subjects. Here we demonstrate that Dr is subject-specific and if used in place of the average value, it affects the χ-positive and χ-negative maps in a structured way, while their sum remains similar. |
| 4173 | Computer 87
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Optimising an Acquisition Protocol and Pipeline for Robust Clinical Quantitative Susceptibility Mapping to Investigate Movement Disorders |
| Oliver C. Kiersnowski1, David L. Thomas2, Adam K. Yamamoto2,3, Mohammed Elgwely2,3, Anastasia Papadaki2,3, Tarek Yousry2,3, John S. Thornton2,3, and Karin Shmueli1 | ||
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, 3Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom |
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Keywords: Susceptibility, Quantitative Susceptibility mapping Quantitative susceptibility mapping (QSM) has been used to investigate movement disorders but has not been integrated into routine clinical practice. We developed an acquisition protocol and a robust QSM pipeline for neuroradiological investigation of movement disorders. We show that high quality QSMs can be acquired using a multi-echo 3D gradient-echo sequence with partial k-space filling in under 6 minutes with only one of eleven patient QSMs corrupted by motion artifacts. We show that Laplacian phase unwrapping and projection onto dipole fields (PDF) background field removal are robust to artifacts across patients with strong susceptibility sources associated with various pathologies. |
| 4174 | Computer 88
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Quantitative comparison of DTI and STI principal eigenvectors |
| Nestor Munoz1,2,3, Carlos Milovic3,4, Christian Langkammer5, Sergio Uribe2,3,6, and Cristian Tejos1,2,3 | ||
1Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, 3Millennium Institute for Intelligent Healthcare Engineering (iHEALTH), Santiago, Chile, 4School of Electrical Engineering, Pontificia Universidad Católica de Valparaiso, Valparaiso, Chile, 5Department of Neurology, Medical University of Graz, Graz, Austria, 6Department of Radiology, Pontificia Universidad Catolica de Chile, Santiago, Chile |
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Keywords: Susceptibility, Susceptibility Diffusion Tensor Imaging (DTI) and Susceptibility Tensor Imaging (STI) are two MRI techniques that produces anisotropy information and fiber direction of biological tissue. For the brain, it has been suggested that both principal eigenvectors (PEV) point towards the same direction (i.e., direction of myelinated axons). However, different resolution of both techniques might produce differences in the PEVs. We proposed a quantitative method to compare DTI and STI PEVs based on the cosine of their angular difference. As expected, we found that PEVs from STI and DTI show similar directions in white matter and that consistency is lost for gray matter and CSF. |
| 4175 | Computer 89
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Total Field Inversion for Quantitative Susceptibility Mapping Based on Boundary Element Modeling |
| Haodong Zhong1, Yi Wang2, and Jianqi Li1 | ||
1Shanghai key lab of magnetic resonance, East China Normal University, Shanghai, China, 2Department of Radiology, Weill Medical College of Cornell University, New York, NY, United States |
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Keywords: Susceptibility, Quantitative Susceptibility mapping, Total Field Inversion This study proposes a novel total field inversion method in which the background field is modeled by discrete boundary elements. In this method, the boundary value of background field and local tissue susceptibility are simultaneously estimated in one step. We validated our method with orthogonality numerical simulation and in vivo data. |
| 4176 | Computer 90
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Brain susceptibility and oxygen extraction fraction relate to cognition altered by white matter hyperintensity in cognitively normal elderly |
| Lin Chen1,2, Anja Soldan3, Zixuan Lin1, Kumiko Oishi4, Kenichi Oishi1, Andreia Faria1, Marilyn Albert3, Peter van Zijl1,2, and Xu Li1,2 | ||
1Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Neurology, Johns Hopkins University, Baltimore, MD, United States, 4Center for Imaging Science, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States |
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Keywords: Susceptibility, Aging We investigated associations of brain iron as measured by QSM, global oxygen extraction fraction (OEF) as measured by TRUST and white matter hyperintensity (WMH) as measure by FLAIR, and their possible interactive effects on both global composite and domain-specific cognitive functions in cognitively normal participants. Significant associations were observed between global WMH burden and tissue susceptibility suggesting contributions from small vessel diseases to tissue iron deposition. Negative associations between tissue susceptibility and cognition as well as positive associations between OEF and cognitive performance were observed within participants with low WMH burden, but not as significant in high WMH group. |
| 4177 | Computer 91
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Including mesoscopic frequency shifts from fibrous structure of white matter improves accuracy of QSM |
| Anders Dyhr Sandgaard1, Valerij G. Kiselev2, Noam Shemesh3, and Sune Nørhøj Jespersen1,4 | ||
1Center for functionally integrative neuroscience, department of clinical medicine, Aarhus University, Aarhus, Denmark, 2Division of Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany, 3Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal, 4Department of Phsysics and Astronomy, Aarhus University, Aarhus, Denmark |
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Keywords: Microstructure, Quantitative Susceptibility mapping Quantitative Susceptibility Mapping (QSM) is a highly utilized MRI modality for mapping tissue susceptibility. However, a limitation of QSM is disregarding mesoscopic field effects associated with WM microstructure and anisotropic susceptibility. Here we present a minimal extension of QSM by including frequency shifts due to the fibrous WM microstructure, while still neglecting susceptibility anisotropy and WM spherical inclusions modelling iron complexes. We find that this step already improves the accuracy of QSM as it is shown by comparison with conventional QSM using a digital phantom that includes microstructural frequency shifts from multiple sources. |
| 4178 | Computer 92
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Exhaustive Comparison of QSM Background Field Removal and Masking using a Realistic Numerical Head Phantom |
| Carlos Milovic1,2, Patrick Fuchs3, Oriana Arsenov3, Oliver C Kiersnowski3, Russell Murdoch3, Laxmi Muralidharan3, Jannette Nassar3, and Karin Shmueli3 | ||
1School of Electrical Engineering, Pontificia Universidad Catolica de Valparaiso, Valparaiso, Chile, 2iHEALTH, Millennium Institute for Intelligent Healthcare Engineering, Santiago, Chile, 3University College London, London, United Kingdom |
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Keywords: Susceptibility, Susceptibility, QSM Removing background fields is an important preprocessing step in QSM, enabling the reconstruction of fine tissue susceptibility variations in the region of interest (ROI) without being corrupted by susceptibility sources outside of this region. This requires a binary mask of the ROI and most background field removal methods are sensitive to the choice of mask. Here we compared 15 background field removal methods across 4 different masks. We found projection onto dipole fields (PDF) to perform best overall, although it is sensitive to the mask. V-SHARP and RESHARP were more robust to masking and showed good performance. |
| 4179 | Computer 93
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Depiction of Small Vessels in QSM is Influenced by Regularization Parameter in TGV-Regularized Parallel Image Reconstruction |
| Alexander Jaffray1, Lara Bartels1, Christian Kames1, and Alexander Rauscher1,2 | ||
1Physics, UBC MRI Research Centre, Vancouver, BC, Canada, 2Department of Pediatrics, UBC, Vancouver, BC, Canada |
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Keywords: Susceptibility, Brain, small vessel, central vein, phase, regularization, vein, qsm, quantitative, mapping Quantitative susceptibility mapping is a possible modality with which to measure and identify diseases involving small vasculature in the brain. However, multi-echo gradient echo images that are a requirement for high quality quantitative susceptibility map reconstruction require long scan durations, limiting clinical utility. This duration can be reduced with the use of parallel imaging strategies, and non-linear reconstruction with total generalized variation regularization is an increasingly popular strategy for undersampled reconstruction. We demonstrate that the depiction of small vessels and surrounding structures in QSM is significantly sensitive to the choice of regularization parameter used in the reconstruction. |
| 4180 | Computer 94
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INR-QSM: unsupervised quantitative susceptibility mapping using implicit neural representation |
| Ming Zhang1, Yuyao Zhang2, and Hongjiang Wei1 | ||
1School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2School of Information and Science and Technology, ShanghaiTech University, Shanghai, China |
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Keywords: Susceptibility, Quantitative Susceptibility mapping, implicit neural representation This study introduced an unsupervised deep learning-based method for QSM reconstruction using implicit neural representation (INR-QSM), a training databases-free method for high-quality QSM reconstruction. In INR-QSM, the susceptibility map was represented as a continuous function of the spatial coordinates. A coordinate-based multilayer perceptron (MLP) parameterized this function, took the coordinate as input and predicted the susceptibility value at the corresponding spatial location. The parameters of MLP were updated by minimizing a custom cost function. Preliminary results on two different datasets demonstrated the potential of INR for unsupervised QSM reconstruction. |
| 4181 | Computer 95
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Imaging the cerebral cortex and substantia nigra in vivo using high-resolution quantitative susceptibility mapping at 5.0-T |
| Ming Zhang1, Lanlan Gao2, Shuheng Zhang2, and Hongjiang Wei1 | ||
1School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2United Imaging Healthcare, Shanghai, China |
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Keywords: Susceptibility, Quantitative Susceptibility mapping, cerebral cortex It is challenging to resolve the human brain microstructure using MRI due to limited SNR and poor image contrast. High-resolution quantitative susceptibility mapping (QSM) at an ultra-high magnetic field could be a useful tool for revealing the subtle structure of the brain due to intrinsic susceptibility differences between tissues. In this study, the six-layer laminae of the cerebral cortex and swallow-tail sign of SN were successfully resolved using high-resolution QSM at 5.0-T. The preliminary result could indicate the potential of high-resolution QSM for investigating the subtle structures of the human brain and related brain disorders. |
| 4182 | Computer 96
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Pseudo COSMOS: Efficient deep learning quantitative susceptibility mapping based on local field transformation |
| De-Rong Huang1, Jhih-Shan Cheng1, Hsiao-Wen Chung2, and Ming-Long Wu1,3 | ||
1Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, 2Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 3Institute of Medical Informatics, National Cheng Kung University, Tainan, Taiwan |
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Keywords: Susceptibility, Machine Learning/Artificial Intelligence A deep learning framework termed pCOSMOS for quantitative susceptibility mapping (QSM) was proposed, which employed a local-field-to-local-field transformation to generate multiple orientation local field maps from single orientation data, followed by COSMOS reconstruction using physical model. 3T multi-orientation data from 10 healthy subjects (7 for training, 3 for testing) were used to investigate performance. Quantitative results compared with MEDI, SFCR, QSMnet, and LPCNN demonstrated superior performance of pCOSMOS comparable to the amongst best algorithms using single orientation data, while showing drastically reduced training time from tens of hours to 3.2 hours. |
| 4183 | Computer 97
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Design of Quadrature RF Coil for Calcium Susceptibility Imaging in Small Tissue Samples |
| Jacob Degitz1, Edith Valle2, Steven M Wright2, and Mary P McDougall1 | ||
1Biomedical Engineering, Texas A&M University, College Station, TX, United States, 2Electrical Engineering, Texas A&M University, College Station, TX, United States |
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Keywords: Susceptibility, Non-Array RF Coils, Antennas & Waveguides One of the earliest significant events in Duchenne muscular dystrophy (DMD) pathology is an elevated influx of calcium ions into afflicted cells. To study this event and its correlation with disease progression, a custom 22mm diameter quadrature volume coil was designed and used to obtain 1H images at 4.7T, the processing protocol was established, and comparisons were made to μCT images. |
| 4184 | Computer 98
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Computationally efficient multi-echo QSM |
| Korbinian Eckstein1, Thanh Thuy Dao2, Ashley Stewart2,3, Simon Daniel Robinson4,5,6,7, Markus Barth2,3,4, and Steffen Bollmann2,3,4 | ||
1School of Information Technology and Electrical Engineering, The University of Queensland, Dutton Park, Australia, 2School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, 3ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, Brisbane, Australia, 4Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, 5Department of Neurology, Medical University of Graz, Graz, Austria, 6Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria, 7High Field MR Center, Medical University of Vienna, Vienna, Austria |
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Keywords: Electromagnetic Tissue Properties, Quantitative Susceptibility mapping, Multi-echo, ROMEO, Phase With increasingly popular multi-echo QSM, the combination of echoes becomes important in terms of accuracy, SNR and computation time. We compared 6 different pipelines with quantitative and Laplacian unwrapping and three different echo combination approaches, weighted averaging of QSMs, combination of the phase, and non-linear fitting. We compared the pipelines on the QSM challenge brain dataset and 7 T in vivo data and conclude that quantitative unwrapping (ROMEO) with weighted frequency combination achieves the best outcomes in terms of accuracy, SNR and computation time. |
| 4185 | Computer 99
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Optimized Quantitative Susceptibility Mapping of Deep Cerebellar Nuclei using the phase of 3D-EPI Multi-Parametric Mapping at 7T |
| Mónica Ferreira1, Rüdiger Stirnberg2, Yannik Völzke2, Daniel Löwen2, Christian Langkammer3, Simon Robinson3,4, Stefan Ropele3, Thomas Klockgether2,5, Tony Stöcker2,6, and Jennifer Faber2,5 | ||
1Clinical Research, DZNE Bonn, Bonn, Germany, 2DZNE Bonn, Bonn, Germany, 3Department of Neurology, Medical University of Graz, Graz, Austria, 4High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria, 5Department of Neurology, University Hospital Bonn, Bonn, Germany, 6Department of Physics and Astronomy, University of Bonn, Bonn, Germany |
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Keywords: Susceptibility, Quantitative Susceptibility mapping RF transmit field inhomogeneities at 7T usually degrade the image quality in regions such as the cerebellum and brainstem, which has so far delayed its use to study cerebellar ataxias with higher fields. We present an optimized pipeline that maximizes the QSM contrast of nuclei in the cerebellum based on multi-echo MPM data. We show that averaging the individual susceptibility maps increases the signal-to-noise ratio (SNR) and reduces the group standard deviation. We introduced a weighted averaging based on the individual acquisition SNRs. Final maps presented high contrast of the dentate nucleus and a high delineation of its denticulated silhouette. |
| 4186 | Computer 100
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Dynamic Geometric Distortion Correction for Quantitative Susceptibility Mapping Using a Multi-Echo 2D-EPI Sequence |
| Oliver C. Kiersnowski1, Patrick Fuchs1, Stephen J. Wastling2,3, John S. Thornton2,3, and Karin Shmueli1 | ||
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, 3Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom |
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Keywords: Susceptibility, Quantitative Susceptibility mapping Echo planar imaging (EPI) suffers from geometric distortions, which can be corrected using reference acquisitions for single-echo EPI, or using field maps calculated from the multiple echoes in multi-echo EPI. The effect of distortion on EPI quantitative susceptibility mapping (QSM) has not been investigated. We compared static and dynamic geometric distortion correction for magnitude images and QSM using multi-echo 2D-EPI acquisitions with and without changes in head position. Multi-echo EPI corrected distortion in both magnitude and QSM images without the need for reference scans. Correcting the local field map in the QSM pipeline was optimal to reduce temporal variance. |
| 4303 | Computer 41
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Multi-echo NODDI for the study of tissue compartmentalisation in transient ischaemic stroke: initial insights |
| Ezequiel Farrher1, Chia-Wen Chiang2, Chang-Hoon Choi1, Kuan-Hung Cho2, Sheng-Min Huang2, Ming-Jye Chen2, Li-Wei Kuo2,3, and N. Jon Shah1,4,5,6 | ||
1Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany, 2Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 3Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 4Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 5JARA – BRAIN – Translational Medicine, RWTH Aachen University, Aachen, Germany, 6Institute of Neuroscience and Medicine – 11, Forschungszentrum Jülich, Jülich, Germany |
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Keywords: Stroke, Diffusion/other diffusion imaging techniques, NODDI, ischemia, multi-echo, transverse relaxation, intra-neurite, extra-neurite Neurite orientation dispersion and density imaging (NODDI) has been broadly used in diffusion MRI for the characterisation of tissue microstructure in healthy ageing and the diseased brain. However, the compartment-specific volume fractions provided by NODDI suffer from echo-time (TE) dependence due to differences in the compartment-specific transverse relaxation times. The recently proposed multi-TE NODDI (MTE-NODDI) model provides both TE-independent compartmental volume fractions and compartment-specific transverse relaxation times. Here we aim to assess the benefits and limitations of using MTE-NODDI for studying the brain tissue microstructure affected by transient ischaemic stroke in MCAo animal models. |
| 4304 | Computer 42
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Evidence of axon beading and loss of extracellular fluid following perfusion and fixation of the marmoset brain |
| Tales Santini1, Naila Rahman1, Alyson Shim1, Matthew Budde2, Stefan Everling1, and Corey Baron1 | ||
1Western University, London, ON, Canada, 2Medical College of Wisconsin, Milwaukee, WI, United States |
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Keywords: Microstructure, Microstructure Previous work showed that advanced diffusion metrics (OGSE and μFA) are sensitive to microstructural changes between in vivo and ex vivo marmoset brain tissues. Here, we utilized Monte Carlo simulations to investigate potential microstructure changes that could be occurring during tissue perfusion and fixation. A comparison between simulations and experiments showed that beading and decreased extracellular space are in agreement with the experimental trends observed. Changing microstructural properties during these processes has implications for studies that compare ex vivo tissue samples with in vivo findings. |
| 4305 | Computer 43
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Free-water DTI and cognitive performance in patients with intracranial vascular occlusion disease and transient ischemic attack |
| Siyuan Fang1, Jian Hai2, Gaiying Li1, Yupeng Wu1, Weiwei Zhao1, and Jianqi Li1 | ||
1Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China, 2Department of Neurosurgery, Tong Ji Hospital, School of Medicine, Tong Ji University,, Shanghai, China |
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Keywords: Data Analysis, Diffusion Tensor Imaging, free-water elimination DTI The objective of this study was to explore the relationship between cognitive impairment and free-water elimination DTI (FWE-DTI) metrics in patients with intracranial vascular occlusion disease (IVOD) and transient ischemic attack (TIA). 22 IVOD with TIA patients were tested with cognitive scales and scanned using a 3T echo-planar imaging sequence. The results show global FWE-DTI metrics were associated with patients' cognitive performance in some domains, which indicated the potential of FWE-DTI as new indices for assessing global brain changes in this disease. |
| 4306 | Computer 44
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Improving microstructural estimation in time-dependent diffusion MRI model with a Bayesian method |
| Kuiyuan Liu1, Tianshu Zheng1, Ruicheng Ba1, Hongxi Zhang2, and Dan Wu1 | ||
1Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China |
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Keywords: Signal Modeling, Microstructure In this study, we proposed Bayesian estimation of tissue microstructures in td-dMRI model, and compared its performance with the traditional non-linear least square fitting method in simulation data and glioma patient data. We found that the performance of Bayesian fitting was dependent on the prior distribution and choice of hyperparameters, and the combination of Bayesian and least-square fitting could achieve reasonable performance without prior information. |
| 4307 | Computer 45
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A general quantitative diffusion MRI model of water exchange, confinement, and hindrance with arbitrary gradient waveform encoding |
| Sisi Li1, Diwei Shi2, Xiaoyu Jiang3,4, Li Chen2, Quanshui Zheng2, Hua Guo1, and Junzhong Xu3,4,5,6 | ||
1Center for Biomedical Imaging Research, Tsinghua University, Beijing, China, 2Center for Nano and Micro Mechanics, Department of Engineering Mechanics, Tsinghua University, Beijing, China, 3Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 4Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 5Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 6Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, United States |
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Keywords: Signal Modeling, Microstructure This study proposed and validated a general diffusion MRI biophysical model enabling simultaneous estimation of cell size, intracellular volume fraction, and transcytolemmal water exchange. The model introduces two-mode intracellular diffusion, corrects for restriction-induced “edge-enhancement” effect, and handles arbitrary diffusion gradient waveforms. The results of both in silico and in vitro experiments suggest this model not only improves the accuracy of estimated microstructural parameters such as cell size but also provides reasonable estimates of water exchange rate constant that is usually ignored previously. Such a comprehensive model may have potential to probe tumor status more precisely which is feasible in clinics. |
| 4308 | Computer 46
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Evaluation of reliability and self-consistency of compartment size-distribution estimations by oscillating gradient spin-echo sequences |
| Melisa L. Gimenez1,2, Leonardo A. Pedraza Pérez1,2, and Gonzalo A. Álvarez1,2,3 | ||
1Instituto Balseiro, CNEA, Universidad Nacional de Cuyo, San Carlos de Bariloche, Argentina, 2Centro Atómico Bariloche, CNEA, CONICET, San Carlos de Bariloche, Argentina, 3Instituto de Nanociencia y Nanotecnologia, CNEA, CONICET, San Carlos de Bariloche, Argentina |
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Keywords: Microstructure, Quantitative Imaging Changes in tissue microstructure are promising biomarkers of neurological diseases. However, achieving robust and reliable, non-invasive diagnostic tools to estimate microstructural features is a major challenge. We perform a systematic analysis using Non-uniform Oscillating Gradient Spin Echo (NOGSE) sequences to estimate size distributions of white-matter phantoms. We evaluate the reliability and self-consistency of the inference method. We find that estimation of the distribution’s mode is very robust and reliable for sharp and smooth gradient modulations. These results contribute to developing reliable diagnostic tools based on quantitative images of tissue microstructure. |
| 4309 | Computer 47
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Mapping Myelin Volume Fraction using Multiple Echo Gradient Echo and Dictionary Matching |
| Mert Şişman1,2, Dominick J. Romano2,3, Alexey V. Dimov2, Ilhami Kovanlikaya2, Pascal Spincemaille2, Thanh D. Nguyen2, and Yi Wang2,3 | ||
1Electrical and Computer Engineering, Cornell University, Ithaca, NY, United States, 2Department of Radiology, Weill Cornell Medicine, New York, NY, United States, 3Biomedical Engineering, Cornell University, Ithaca, NY, United States |
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Keywords: Microstructure, White Matter Myelin Volume Fraction (MVF) is an important biomarker of demyelination various diseases Multiple Sclerosis. In this study, we propose a method that provides quantitative MVF maps from routine multiple echo gradient echo acquisitions and dictionary matching. The dictionary is generated using the Hollow Cylindrical Fiber Model (HCFM) and employs both the magnitude signal decay and QSM obtained from the mGRE phase. The obtained maps show both qualitative and quantitative superiority over the standard multiexponential fitting-based myelin water fraction (MWF) maps. |
| 4310 | Computer 48
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The effect of inter-individual differences and number of fiber directions on possible orientation dependence of myelin water imaging |
| Tigris Joseph1,2, Sarah Morris1,2,3, Shannon H. Kolind1,2,3,4, Alex MacKay1,3, Irene M. Vavasour2,3, and Cornelia Laule1,2,3,5 | ||
1Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada, 3Radiology, University of British Columbia, Vancouver, BC, Canada, 4Medicine, University of British Columbia, Vancouver, BC, Canada, 5Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada |
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Keywords: Microstructure, Relaxometry, myelin, white matter, orientation dependence, fiber direction, BedpostX, myelin water fraction, myelin water imaging Previous work suggests myelin water fraction (MWF) may be fibre orientation dependent. We compared MWF to fiber angle (from diffusion tensor imaging (DTI)) in white matter (WM) from 16 healthy participants using BedpostX to estimate the number of fiber directions. MWF vs. fiber angle graphs showed trends which varied between participants, suggesting that real myelination differences may be at least partly responsible for apparent orientation dependence of MWF. There were little obvious differences between trends with 1, 2, or 3+ fiber orientations in WM, suggesting number of fibers directions within a voxel does not impact orientation dependence. |
| 4311 | Computer 49
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A new qMRI approach for mapping microscopic water populations and tissue relaxivity in the in-vivo human brain |
| Shir Filo1 and Aviv A Mezer1 | ||
1The Edmond and Lily Safra Center for Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel |
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Keywords: Microstructure, Magnetization transfer We present an array of new quantitative maps, highlighting different aspects of the tissue’s water. Furthermore, our technique allows to calculate the voxel-wise tissue relaxivity, associated with the molecular composition of the brain. Our approach is based on the pioneering two-site exchange model. We implemented it for magnetization-transfer weighted water content mapping of brain tissue for the first time. The new in-vivo MRI measurements conform well with the theory. They can be easily acquired with the standard quantitative MRI protocol and do not require complex data fitting. Therefore, the proposed technique may further advance human brain research and diagnosis. |
| 4312 | Computer 50
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Parameter inference using continuous change in degenerate biophysical diffusion models |
| Daniel Z.L. Kor1, Hossein Rafipoor1, Michiel Cottaar1, Saad Jbabdi1, Karla L. Miller1, and Amy F.D. Howard1 | ||
1Wellcome Centre for Integrative Neuroimaging, FMRIB, University of Oxford, Oxford, United Kingdom |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, biophysical diffusion modelling Biophysical modelling of diffusion MRI (dMRI) may elucidate key microstructural features. However, most models include many input parameters, making simultaneous estimations of all parameters ill-posed. To overcome this, the recently published Bayesian framework EstimatioN for CHange (BENCH) characterises changes (variation) in parameters across multiple measurements/samples, rather than inferring the actual parameters from a single measurement/sample. BENCH has been previously applied to understand group-wise changes (e.g., patients vs. controls) in biophysical parameters. Here, we adapted BENCH to interpret situations of continuous change and validate its behaviour using synthetic dMRI data from numerical simulations. |
| 4313 | Computer 51
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Diffusion MRI with spherical tensor encoding at high b-values reveals cerebellar grey matter abnormalities in movement disorders |
| Chantal Tax1,2, Sila Genc3, Claire L MacIver1,4, Markus Nilsson5, Mark Wardle6, Filip Szczepankiewicz5, Derek K Jones1, and Kathryn Peall4 | ||
1CUBRIC, Cardiff University, Cardiff, United Kingdom, 2Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 3Department of Neurosurgery, The Royal Children's Hospital, Parkville, Australia, 4Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom, 5Diagnostic Radiology, Clinical Sciences Lund, Lund Unversity, Lund, Sweden, 6Cardiff and Vale University Health Board, University Hospital of Wales Cardiff, Cardiff, United Kingdom |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Movement disorders Most work on understanding movement disorder pathophysiology has focused on grey/white matter volumetric (macrostructural) and white matter microstructural effects, limiting understanding of frequently implicated grey matter microstructural differences. Using ultra-strong diffusion MRI with spherical tensor encoding, a persistent MRI signal was seen in healthy cerebellar grey matter at ultra-high diffusion-weightings. This work quantifies the proportion of this signal, previously ascertained to originate from small spherical spaces, in a clinical cohort, including patients with diagnosed movement disorders where the cerebellum has been implicated in symptom pathophysiology. Significant differences were found in individuals diagnosed with SCA6 and dystonia compared to age-matched controls. |
| 4314 | Computer 52
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Twinkle, twinkle, T2*, still we wonder what you are |
| Pippa Storey1 and Dmitry S. Novikov1 | ||
1Department of Radiology, New York University School of Medicine, New York, NY, United States |
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Keywords: Microstructure, Relaxometry, T2* decay In the absence of macroscopic magnetic field inhomogeneity, the decay of gradient-echo signals is generally observed to be approximately monoexponential, with time constant $$$T_2^*$$$. The monoexponential behavior is typically attributed to diffusion, which averages out the dephasing of spins due to microstructural sources of magnetic susceptibility. The rationale is that, over times long enough for spins to have explored the microstructure, the cumulants of the spins’ phase distribution should increase linearly with time. By means of a simple counterexample, we demonstrate that this assumption is incorrect, thereby calling into question the mechanism underlying the monoexponential decay of gradient-echo signals. |
| 4315 | Computer 53
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High Resolution In Vivo Diffusion Tensor Distribution MRI of the Whole Human Brain with 300 mT/m Gradients |
| Kulam Najmudeen Magdoom1,2, Alexandru V. Avram1,2, Dario Gasbarra3, Thomas Witzel4, Susie Yi Huang4, and Peter J Basser2 | ||
1The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF) Inc., Bethesda, MD, United States, 2National Institute of Health, Bethesda, MD, United States, 3University of Helsinki, Helsinki, Finland, 4Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Multiple diffusion encoding Whole brain DTD MRI was performed at 1.2 mm isotropic resolution in-vivo using 300 mT/m gradients. An efficient and easy to implement interfused-PFG (iPFG) sequence was used to acquire multiple diffusion encoded images. Size, shape and orientation heterogeneity are measured and mapped from the estimated DTD along with a new form of tractography. The results show varying heterogeneity in different areas of the cerebral cortex, and subcortical and white matter regions. DTD tractography captured complex fiber configurations absent in DTI tractography. |
| 4316 | Computer 54
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Mapping biophysical changes in stroked tissue via the Standard Model with Exchange (SMEX) diffusion model |
| Rita Alves1, Rafael Neto Henriques1, Jonas Olesen2,3, Sune Nørhøj Jespersen2,3, and Noam Shemesh1 | ||
1Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal, 2Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 3Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Exchange Apparent diffusion coefficient (ADC) contrasts in stroke are still debated over 30 years after their discovery, mainly because of the nonspecific nature of ADC. Here, we harness Standard Model with Exchange (SMEX) measurements in ex-vivo stroked brains, to investigate how tissue microstructure is changed with ischemia. SMEX provides insight into neurite density, diffusivity and – importantly – exchange between neurite and extracellular environments. Using an extensive dataset, we find changes in neurite density and diffusivity that are consistent with neurite beading effects, which were further confirmed histologically. Dramatic reductions in exchange rates in the ischemic core were also observed. |
| 4317 | Computer 55
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On the practical influence of extra-axonal heterogeneity in a numerically informed model of extra-axonal water diffusion |
| Kevin D Harkins1,2,3, Junzhong Xu1,2, John C Gore1,2,3, and Mark D Does2,3 | ||
1Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 2Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States |
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Keywords: Simulations, Microstructure This study explores the role of extra-axonal environment on the time dependent diffusion coefficient of extra-axonal water in white matter. Monte Carlo simulations of water diffusion in geometries with varying extra-axonal heterogeneity were compared with a proposed analytic model. The results agree with previously published power-law relationships that depend on structural order, but also uncovers trends between model parameters with characteristics of extra-axonal space. |
| 4318 | Computer 56
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MULTI-SHELL DIFFUSION MRI TO INVESTIGATE THE EFFECTS OF HYPERTENSION ON RAT BRAIN |
| Haley Elizabeth Wiskoski1,2, Loi Do1, Marc Zempare3, Natalie Carey3, Amy Delmendray3, Kimberly Young3, Kimberly Bohne3, Monica Chawla3, Pradyumna Bharadwaj4, Kenneth Mitchell5, Gene Alexander3,4,6, Carol Barnes3,4, and Theodore Trouard1,3,7 | ||
1Department of Biomedical Engineering, The University of Arizona, Tucson, AZ, United States, 2James C. Wyant College of Optical Sciences, The University of Arizona, Tucson, AZ, United States, 3Evelyn F. McKnight Brain Institute, The University of Arizona, Tucson, AZ, United States, 4Department of Psychology, Neurology, and Neuroscience, The University of Arizona, Tucson, AZ, United States, 5Health Sciences Center, Tulane University, New Orleans, LA, United States, 6Division of Neural Systems, Memory, and Aging, The University of Arizona, Tucson, AZ, United States, 7Department of Medical Imaging, The University of Arizona, Tucson, AZ, United States |
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Keywords: Microstructure, Diffusion/other diffusion imaging techniques, DTI, fixels, Tractography & Fibre Modeling, Software Tools, Hypertension Hypertension is associated with an increased risk of cardiovascular disease and cognitive decline in aging humans. This study investigated longitudinal effects of induced HTN in regional and microstructural neuroanatomy of F344 rats using noninvasive diffusion-weighted MRI and fixel-based analysis. Single-shot spin-echo EPI along 64 diffusion directions and three shells (b=1000, 2000, and 3000 s/mm2) was performed. Microstructural changes in the brain appeared in certain regions after 10 weeks of hypertension, yet, most regions remained unaffected, contrasting peripheral organs which showed dramatic fibrosis due to the HTN. This likely demonstrates a robust protective mechanism of the central nervous system. |
| 4319 | Computer 57
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NODDI-based identification of white matter tracts in regions of peritumoral edema: a validation study in brains bearing meningioma tumors. |
| Sasha Hakhu1, Jennapher Lingo VanGilder1, Lucas Paulson1, Leland Hu2, Yuxiang Zhou2, Kurt Schilling3, and Scott Beeman1 | ||
1School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States, 2Mayo Clinic, Scottsdale, AZ, United States, 3Vanderbilt University, Nashville, TN, United States |
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Keywords: White Matter, Diffusion/other diffusion imaging techniques White matter (WM) tract detection proximal to brain tumors, surrounded by vasogenic edema during tumor resection is critical. Previous work has shown that NODDI presents a more accurate quantification of WM in edema as compared to DTI. However, these studies included gliomas and metastases, which are known to infiltrate WM. Here, we focus on validating the use of the NODDI model for WM identification in edema only in non-invasive meningiomas. Our results showed that DTI-derived FA of WM near edematous regions were lower than contralateral WM in non-edematous regions; in contrast, NODDI-derived ODI values for the same regions remained comparable. |
| 4320 | Computer 58
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Probing restriction and exchange in the human brain using free waveforms on a high-performance gradient system |
| Arthur Chakwizira1, Ante Zhu2, Thomas Foo2, Carl-Fredrik Westin3, Filip Szczepankiewicz1, and Markus Nilsson4 | ||
1Medical Radiation Physics, Lund, Lund University, Lund, Sweden, 2GE Research, Niskayuna, New York, NY, United States, 3Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 4Clinical Sciences Lund, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure Monitoring time dependence with diffusion MRI provides observables sensitive to restricted diffusion and exchange. Probing these phenomena by simply varying the diffusion time is a challenge because they have opposite effects on the diffusion-weighted signal and may cancel each other. A theoretical framework was recently proposed for disentangling the effects using free gradient waveforms. Here we explore the potential of the approach for neuroimaging in vivo using a high-performance gradient system. Results demonstrate unprecedented ability to disentangle the effects of restriction and exchange. Maps of the exchange rate show plausible contrast in both cortical and subcortical regions of the brain. |
| 4321 | Computer 59
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Evolution of Microstructural Changes in a Mouse Model of Mild Traumatic Brain Injury |
| Naila Rahman1, Kathy Xu1, Matthew Budde2, Arthur Brown1, and Corey Baron1 | ||
1Robarts Research Institute, London, ON, Canada, 2Medical College of Wisconsin, Milwaukee, WI, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Brain Injury Single mild concussive impacts remain sparsely explored by in vivo neuroimaging techniques. Multimodal microstructural MRI has shown increased sensitivity and specificity to microstructural changes in various disease and injury models. In this work, we apply oscillating gradient spin-echo (OGSE) diffusion MRI, microscopic anisotropy (µA) diffusion MRI, and magnetization transfer (MT) MRI longitudinally to increase sensitivity to smaller spatial scales, disentangle fiber orientation dispersion from true microstructural changes, and acquire myelin sensitivity, respectively. We demonstrate that multimodal microstructural MRI provides sensitivity to evolving changes following a mild impact in both acute and chronic regimes, with OGSE demonstrating higher sensitivity than µA. |
| 4322 | Computer 60
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Characterization of white matter myelinated and unmyelinated axons from diffusion MRI perspective |
| Ali Abdollahzadeh1, Ricardo Coronado-Leija1, Subah Mehrin1, Hong-Hsi Lee2, Alejandra Sierra3, Els Fieremans1, and Dmitry S. Novikov1 | ||
1Radiology, New York University School of Medicine, New York, NY, United States, 2Radiology, Harvard Medical School, Boston, MA, United States, 3A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland |
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Keywords: Diffusion/other diffusion imaging techniques, Simulations, Time-dependence diffusion We segment all myelinated and unmyelinated axons from electron microscopy (EM) images of brain white matter (WM) of a mouse and a rat and quantify their cross-sectional morphology. We provide the exact relation between the long-time limit of the along-axon diffusion coefficients and the geometry of segmented intra-axonal spaces (IAS). By performing Monte Carlo (MC) simulations of diffusion in the IASs at varying diffusion times, we establish the time-dependence of diffusion along segmented myelinated and unmyelinated axons and validate the relation between axonal geometry and the long-time behavior of the longitudinal diffusion coefficient. |
| 4323
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Computer 61
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Co-Hyperpolarized [13C,15N2]urea + [1-13C]pyruvate for Perfusion and Metabolic Imaging of the Abdomen in Healthy Volunteers |
| Yaewon Kim1, Hsin-Yu Chen1, Tanner Nickles1, Jeremy Gordon1, Peder Larson1, Xiaoxi Liu1, Louise Magat1, Philip Lee1, Daniel Gebrezgiabhier1, Cornelius von Morze2, Dan Vigneron1,3, and Michael Ohliger1 | ||
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 2Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, United States, 3Department of Neurological Surgery, University of California, San Francisco, CA, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Perfusion [13C,15N2]urea and [1-13C]pyruvate were polarized together using dynamic nuclear polarization and simultaneously injected into healthy volunteers for simultaneous imaging of metabolism and perfusion in the abdomen. Whole-abdomen images were successfully obtained and the distribution of urea was compared to pyruvate and its metabolites. While the relative intensity in various organs were similar between urea and pyruvate, the temporal courses were different. This represents the first use of co-polarized pyruvate and urea in the human abdomen, and will be a powerful potential tool for simultaneous imaging of perfusion and metabolism in tumors and metabolic diseases. |
| 4324 | Computer 62
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Bias Correction for Improved Quantification of Hyperpolarized [1-13C]Pyruvate Cerebral Perfusion |
| Jasmine Hu1, Sana Vaziri1, Nikolaj Bøgh2, Yaewon Kim1, Adam Autry1, Robert Bok1, Yan Li1, Christoffer Laustsen2, Peder Larson1, Duan Xu1, Daniel Vigneron1, and Jeremy Gordon1 | ||
1UC San Francisco, San Francisco, CA, United States, 2MR Research Center, Clinical Medicine, Aarhus University, Aarhus, Denmark |
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Keywords: Hyperpolarized MR (Non-Gas), Perfusion, Brain Bias correction of hyperpolarized [1-13C]pyruvate brain MRI allows for improved quantification of cerebral perfusion. In the healthy volunteers studied, bias corrected pyruvate and ASL rCBF exhibited higher correlation than uncorrected pyruvate and ASL rCBF. We hypothesize that N4ITK bias correction can be used to remove low frequency inhomogeneities from hyperpolarized MRI before single-metabolite analyses. |
| 4325 | Computer 63
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Estimating T2 relaxation rates of Lactate with Hyperpolarized C13 MRI using bSSFP and Pharmacokinetic Modelling |
| Sule Sahin1,2, Xiaoxi Liu1, Nicholas Dwork3, Shuyu Tang4, Zhen Jane Wang1, and Peder E.Z. Larson1 | ||
1Radiology, University of California, San Francisco, San Francisco, CA, United States, 2UC Berkeley - UCSF Graduate Program in Bioengineering, Berkeley, CA, United States, 3Biomedical Informatics, University of Colorado School of Medicine, Aurora, CO, United States, 4HeartVista, Los Altos, CA, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Modelling, Kidney, Tumor Lactate T2 values were fit in vivo for animal and human hyperpolarized carbon-13 pyruvate MR datasets. A pharmacokinetic model was used to leverage T2 weighting of a bSSFP acquisition. For healthy rat kidneys lactate T2 values were 0.929 ± 0.111s, for TRAMP tumor 1.663 ± 0.485s, for human RCC tumor 1.119 ± 0.168s and for human RCC normal-appearing region 1.089 ± 0.375s. Lactate T2 maps showed heterogeneity across the kidney of RCC patients but median T2 values were consistent across patients. This work demonstrates a method of using bSSFP hyperpolarized data to fit T2 values. |
| 4326 | Computer 64
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Fractional-order total variation penalised hyperpolarized metabolic model fitting in the human heart |
| Jack J. Miller1,2, Justin Y C Lau3, Andrew Lewis4, and Christoffer Laustsen1 | ||
1The MR Research Centre, Aarhus University, Aarhus, Denmark, 2OCMR, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, 3GE Healthcare, Schenectady, NY, United States, 4OCMR, University of Oxford, Oxford, United Kingdom |
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Keywords: Hyperpolarized MR (Non-Gas), Cardiovascular Fractional-order derivatives represent the smooth analytic continuation of differentiation by a non-integer order. Their use for total-variation spatial regularisation has been proposed as they effectively smoothly interpolate data from the entirety of the image domain, and are reported to avoid ``blocky'' artefacts and better capture edges. Here, we show that their use permits the rapid and parsimonious optimisation of a piecewise metabolic model in the human heart, able to reconstruct terms representing perfusion delay and apparent metabolic rate constants of interconversion. |
| 4327 | Computer 65
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Data Standardization and DICOM Integration for Hyperpolarized 13C MRI |
| Ernesto Diaz1, Renuka Sriram1, Jeremey W. Gordon1, Avantika Sinha1, Xiaoxi Liu1, Jenna Bernard1, Daniel B. Vigneron1, Zhen Jane Wang1, Duan Xu1, and Peder E.Z. Larson1 | ||
1Radiology & Biomedical Images, University of California,San Francisco, San Francisco, CA, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Contrast Mechanisms, Data,DICOM Hyperpolarized (HP) 13C MRI has shown promise as a valuable modality for in vivo measurements of metabolism, and is currently in human trials at over 15 human research sites worldwide. It is important to adopt standardized data storage practices as it will allow sites to meaningfully compare data. We propose using specific Attributes in DICOM format, including “Contrast Agents”, and provide a Python based implementation to add these values for individual studies. Moreover, we propose best practices for HP 13C MRI data storage that will support future multi-site trials and research studies and technical developments of this imaging technique. |
| 4328 | Computer 66
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Hyperpolarized 15N choline chloride to study choline metabolism in prostate cancer at 7T. |
| William Dominguez-Viqueira1, Veronica C Estrella2, Epifanio Ruiz1, Gary V Martinez3, and Jung W Choi4 | ||
1Small Animal Imaging Lab, Moffitt Cancer Center, Tampa, FL, United States, 2Moffitt Cancer Center, Tampa, FL, United States, 3MD Anderson Cancer Center, Houston, TX, United States, 4Radiology Department, Moffitt Cancer Center, Tampa, FL, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Cancer Elevated concentrations of choline and phosphocholine are known to be a metabolic hallmark for tumor hypoxia in prostate cancer. An inhibition of hyperpolarized 15N choline to phosphocholine conversion is shown in this work in hypoxic PC-3 cells in-vitro as seen by other methods in the literature. In-vivo tumor volumes and hyperpolarized 15N phosphocholine to choline ratios were measured in twelve NSG mice with subcutaneous flank xenograft PC-3 tumors, showing a moderate correlation. The findings in this work support the hypothesis that hyperpolarized 15N-Choline may be useful as a marker of malignancy. |
| 4329 | Computer 67
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Assessment of Cardiac TCA Cycle Activity with Hyperpolarized [1-13C]Acetyl-L-Carnitine |
| Jun Chen1, Tamara Kaur Singh2, Sarah Al Nemri1, Kelvin L Billingsley 3, and Jae Mo Park1,4 | ||
1Advanced Imaging Research Center, UT Southwestern Medical Center at Dallas, Dallas, TX, United States, 2Chemistry, California State University, Fullerton, Fullerton, CA, United States, 3Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States, 4Department of Radiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Metabolism Hyperpolarized [1-13C]acetyl-L-carnitine was developed as a probe to investigate cardiac TCA cycle activity in vivo. [5-13C]Glutamate, which is produced via TCA cycle intermediate a-ketoglutarate, was successfully observed in rat heart under both fasting and fed conditions. Importantly, although pyruvate dehydrogenase activity is decreased in the fasted state, [5-13C]glutamate remained observable at appreciable levels, suggesting that [1-13C]acetyl-L-carnitine provides complementary information relative to standard assessments of pyruvate oxidation with hyperpolarized [1-13C]pyruvate. In turn, this novel probe may facilitate comprehensive metabolic analyses of acetyl-CoA uptake by the TCA cycle for various cardiac applications. |
| 4330 | Computer 68
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SABRE Hyperpolarization of Bulky, Nitrile Containing Anti-Cancer Drugs, Letrozole and Anastrozole, with Long Hyperpolarization Lifetimes |
| Keilian Macculloch1, Austin Browning1, Patrick TomHon1, Soren Lehmkuhl1, Eduard Y Checkmenev2,3,4, and Thomas Theis1,5 | ||
1Chemistry, North Carolina State University, Raleigh, NC, United States, 2Wayne State University, Detroit, MI, United States, 3Karmanos Cancer Institute, Detroit, MI, United States, 4Russian Academy of Science, Moscow, Russian Federation, 5University of North Carolina, Chapel Hill, NC, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Cancer Signal Amplification By Reversible Exchange in Shields Enable Alignment Transfer to Heteronuclei (SABRE-SHEATH) was employed to boost 15N magnetic resonance sensitivity on common anti-cancer agents. The SABRE-SHEATH hyperpolarization dynamics of letrozole and anastrozole were independently optimized with respect to solution temperature and polarization transfer field. These studies enabled single scan 15N detection of the drugs at natural isotopic abundance working with mM concentrations for over 30 minutes, paving the way for more sensitive drug development. |
| 4331 | Computer 69
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Metabolic Dysregulation in Rat Brain with Diabetes and Alzheimer’s Disease as Assessed by Hyperpolarized [1-13C] Pyruvate |
| Keshav Datta1, Shie-Chau Liu1, Usman Rehman2, James Graham3, Ralph Hurd1, Daniel Spielman1, and Thomas Jue2 | ||
1Radiology, Stanford University, Stanford, CA, United States, 2Biochemistry and Molecular Medicine, University of California, Davis, CA, United States, 3Nutrition, University of California, Davis, CA, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Alzheimer's Disease, Neurodegenerative Metabolism Diabetes MRI MRS Epidemiology studies have detected type 2 diabetes (T2D) increasing the risk of Alzheimer’s disease (AD). How insulin insensitivity in T2D influences AD onset/progression poses a puzzling question. In this study using dynamic nuclear polarization (DNP) magnetic resonance (MR) experiments, we interrogated the metabolic alteration by following the conversion of [1-13C]Pyr in the brain of control (CRL), T2D with no AD (T2D-AD -/-), and T2D with AD (T2D-AD +/-) rats. Pyruvate dehydrogenase (PDH) activity decreases in T2D and decreases further in T2D with AD. |
| 4332 | Computer 70
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Effects of Gadolinium on the Dynamic Nuclear Polarization of [15N3] Metronidazole |
| David O. Guarin Bedoya1,2, Sameer M. Joshi3, Anna Samoilenko3, Mohammad S. H. Kabir3, Atsushi M. Takahashi4, Jan Henrik Ardenkjaer-Larsen2,5, Eduard Y. Chekmenev3,6, and Yi-Fen Yen1 | ||
1Radiology Department, Athinoula A. Martinos Center for Biomedical Imaging, MGH, Charlestown, MA, United States, 2Polarize ApS, Frederiksberg, Denmark, 3Department of Chemistry, Wayne State University, Detroit, MI, United States, 4Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States, 5Department of Health Technology, Technical University of Denmark, Lyngby, Denmark, 6Russian Academy of Sciences, Moscow, Russian Federation |
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Keywords: Hyperpolarized MR (Non-Gas), Contrast Agent, Contrast Mechanism In this work, we studied the dynamic nuclear polarization (DNP) process of [15N3]metronidazole (MNZ), an FDA-approved antibiotic that achieved good polarization (~6%) with very short polarization build-up time constants (~12min). We used Electron Paramagnetic Resonance (EPR) spectroscopy to show that a sample of [15N3]MNZ + trityl AH111501 had narrower EPR linewidth and larger magnitude than AH111501 alone, indicating an efficient polarization transfer from the radical electrons to 15N and supporting our observations of fast DNP buildup. We also demonstrated that an addition of gadolinium-based compound to the [15N3]MNZ +AH111501 sample broadened the EPR spectrum and prolonged DNP buildup as observed. |
| 4333 | Computer 71
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Factors influencing human brain metabolite SNR in studies with hyperpolarized [1-13C]pyruvate |
| Mary McLean1, Ashley Grimmer1, Elizabeth Latimer1, Alixander Khan1, Pascal Wodtke1, Joshua Kaggie1, James Grist2, Fulvio Zaccagna1, Martin Graves1, and Ferdia Gallagher1 | ||
1Radiology, University of Cambridge, Cambridge, United Kingdom, 2Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom |
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Keywords: Hyperpolarized MR (Non-Gas), Brain Human brain metabolite SNR in studies with hyperpolarized [1-13C]pyruvate was found to best correlate with percentage polarization in the liquid state and with the polarization adjusted for pyruvate concentration and the delay between dissolution and injection (‘injectable signal’). It did not depend on the volume of pyruvate injected, suggesting that the current dose (which is adjusted by body weight) is adequate. It may be worth further exploring whether the SNR of bicarbonate could be enhanced by a longer delay between injection and the start of acquisition. Liquid and solid-state polarizations did not correlate, highlighting the importance of liquid state measurement. |
| 4334 | Computer 72
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Para-hydrogen signal-enhanced 1-13C-pyruvate-d3 for rapid metabolic tumor imaging |
| Henning Schroeder1, Theresa Hune1, Salvatore Mamone1, Anil Jagtap1, Sonja Sternkopf1, Gabriele Stevanato1, Sergey Korchak1, Claudia Fokken2, Christoph Müller3,4, Dorothea Becker2, Andreas Schmidt3,4,5, and Stefan Glöggler1 | ||
1NMR Signal Enhancement, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany, 2Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany, 3Division of Medical Physics, Department of Radiology, Medical Center, University of Freiburg, Freiburg, Germany, 4German Cancer Consortium (DKTK), partner site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany, 5Intergrative Biosciences (Ibio), Department of Chemistry, Karmanos Cancer Institute (KCI), Wayne State University, Detroit, MI, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Cancer Using a Parahydrogen-induced polarization (PHIP) based approach, we enhanced the signal of pyruvate, one of the key metabolites for energy production in the body. By injecting this metabolite into a mouse carrying a human melanoma tumor, we could perform real time spectroscopy and visualization of the tumors metabolism using a NMR machine. This offers a fast and powerful tool for metabolic imaging without using radio tracers. |
| 4335 | Computer 73
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An open-source echo-planar imaging sequence for hyperpolarized 13C MRI |
| Tyler Blazey1 and Cornelius von Morze1 | ||
1Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Hyperpolarized MR (Non-Gas) HP 13C MR imaging in humans has largely been restricted to GE scanners. To facilitate a human HP 13C imaging program at our institution and expand the translational potential of HP 13C MRI in general, we have developed a 3D symmetric EPI sequence for imaging HP 13C agents on Siemens scanners. Sequence development was performed using Pulseq, a flexible open-source tool for prototyping platform-agnostic pulse sequences. Metabolites were selectively excited using spectral-spatial RF pulses. Optional acceleration was achieved using partial Fourier undersampling in the slice direction. The sequence was tested using a thermally polarized phantom and a HP [1-13C]pyruvate phantom. |
| 4336 | Computer 74
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Quantitative Evaluation of kPL Dependence on Pyruvate Concentration in Anaplastic Thyroid Cancer Cell Suspensions using Hyperpolarized 13C NMR |
| Collin J. Harlan1,2, Yunyun Chen3, Gary V. Martinez2, Vlad C. Sandulache4, Stephen Y. Lai3,5,6, and James A. Bankson1,2 | ||
1The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States, 2Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 3Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 4Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Houston, TX, United States, 5Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 6Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Translational Studies Metabolic imaging of hyperpolarized pyruvate can provide new insight into tumor progression and response to therapy. Pharmacokinetic modeling can be used to determine kPL, the apparent rate constant for conversion of hyperpolarized pyruvate into lactate. In this work, we sought to characterize the effect of hyperpolarized pyruvate concentration on intracellular kPL in ATC cell suspensions using a two-compartment pharmacokinetic model for kPL quantification. Improved understanding of the effects of concentration on intracellular chemical conversion rates could lead to more accurate quantification of in vivo and clinical hyperpolarized MRI imaging biomarkers of metabolism. |
| 4337 | Computer 75
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Increasing the hyperpolarization level on PHIP-SAH polarized pyruvate in a fully biocompatible solution. |
| Francesca Reineri1, Silvio Aime1, Carla Carrera1,2, Eleonora Cavallari1, Erika Cerutti1, and Ginevra Di Matteo1 | ||
1Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy, 2National Research Council, Torino, Italy |
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Keywords: Hyperpolarized MR (Non-Gas), Hyperpolarized MR (Non-Gas), metabolism Hyperpolarized [1-13C]pyruvate can be obtained by means of ParaHydrogen Induced Polarization-Side Arm Hydrogenation, a hyperpolarization technique that is significantly more cost effective and faster than the gold-standard method d-DNP. The hyperpolarization level that we reported previously, for the fully biocompatible aqueous solution of this HP metabolite, was sufficient to carry out metabolic studies, but still low. In this work we show that the use of a lower catalyst concentration, together with a co-catalyst, and an improved magnetic field cycle profile for spin order transfer can double the HP level on this metabolite. |
| 4338 | Computer 76
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Efficient 13C-hyperpolarization of lactate using parahydrogen and proton exchange. |
| Kolja Them1, Jule Kuhn1, and Jan-Bernd Hövener1 | ||
1Radiology and Neuroradiology, MOIN CC and SBMI, UKSH, Kiel, Germany |
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Keywords: Hybrid & Novel Systems Technology, Hyperpolarized MR (Non-Gas), Hyperpolarized Lactate, Parahydrogen, Proton Exchange Hyperpolarization of biological molecules1,2,3 is a promising approach for metabolic MR imaging. Hyperpolarization methods based on parahydrogen and proton exchange4,5 promise almost universal polarization of many molecules, but current polarization yields are relatively low. Here, we present a new variant of Parahydrogen-Induced Polarization relayed via proton exchange (PHIP-X), which we demonstrate using the important biomolecule lactate. Polarization transfer between labile and covalent bound protons at different fields, combined with an RF pulse sequence, enables significantly enhanced 13C polarization of lactate. We believe that this approach may be used as a general strategy for the polarization of various biomolecules. |
| 4339 | Computer 77
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GRAPPA-Accelerated Flyback EPI with Controlled Aliasing for Hyperpolarized Pyruvate |
| Enya E. Hachem1, Sung-Han Li2, Mai Huynh2, Junjie Ma3, and Jae Mo Park1,2,4 | ||
1Electrical Engineering, UT Dallas, Richardson, TX, United States, 2Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, 3GE Healthcare, New York, NY, United States, 4Department of Radiology, UT Southwestern Medical Center, Dallas, TX, United States |
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Keywords: Image Reconstruction, Phantoms In this study, we introduced the parallel imaging technique GRAPPA to the flyback EPI with controlled aliasing in order to accelerate the acquisition time while simultaneously reducing artifacts. The GRAPPA-accelerated flyback EPI was characterized using MR phantoms with varying SNR and acceleration factor (R) and the feasibility of simultaneous bicarbonate and lactate imaging with the proposed scheme was also demonstrated. The proposed acquisition method has potential advantages for in vivo studies with hyperpolarized substrates by shortening acquisition time, improving spatial resolution, and increasing effective flip angles. |
| 4340 | Computer 78
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Improving temporal resolution in dynamic hyperpolarized 13C spiral chemical shift imaging using low rank plus local sparse reconstruction |
| Minjie Zhu1, Dirk Mayer1, Aditya Jhajharia1, and Joshua Rogers1 | ||
1University of Maryland, Baltimore, Baltimore, MD, United States |
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Keywords: Image Reconstruction, Hyperpolarized MR (Non-Gas) Improve the accuracy of under-sampled dynamic images for lower intensity metabolites with low rank and local sparsity reconstruction |
| 4341 | Computer 79
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Towards Biomedical Applications of Parahydrogen Induced Polarization by Side-Arm Hydrogenation Using SAMBADENA |
| Henri de Maissin1,2, Obaid Mohiuddin1, Marvin Herzog1, Eduard Y. Chekmenev3,4, Sergey Korchak5,6, Stefan Glöggler5,6, Jan-Bernd Hövener7, Maxim Zaitsev1, Dominik v. Elverfeldt1, and Andreas B. Schmidt1,3,8 | ||
1Division of Medical Physics, University Medical Center Freiburg, Freiburg im Breisgau, Germany, 2German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany, 3Integrative biosciences (Ibio), department of Chemistry, Wayne state university, Detroit, MI, United States, 4Russian Academy of Sciences (RAS), Moscow, Russian Federation, 5NMR Signal Enhancement Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany, 6Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany, 7Section Biomedical Imaging, Molecular Imaging North Competence Center, Kiel, Germany, 8German Cancer Consortium (DKTK), Heidelberg, Germany |
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Keywords: High-Field MRI, Hyperpolarized MR (Non-Gas), parahydrogen cancer spectroscopy Parahydrogen-induced Polarization (PHIP) by Synthesis Amid the Magnet Bore Allows Dramatically Enhanced Nuclear Alignment (SAMBADENA) of agents in situ within the MRI magnet and requires very little hardware in addition to the MRI system. However, side-arm hydrogenation (PHIP-SAH), fast side-arm cleavage and purification have not been attempted yet.Here, we present a SAMBADENA setup made from commercially-available components for future preclinical applications. Using this setup, we demonstrate high 13C polarizations of 17% for 25mM ethyl-[1-13C]-acetate. In addition, for ethyl-pyruvate, fast side-arm cleavage and removal of 96% of the organic solvent within 10s to obtain pyruvate in neat water is demonstrated. |
| 4475 | Computer 41
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RECOMPOSE – Reproducing DECOMPOSE Using Susceptibility Maps Acquired for Clinical Research |
| Patrick Fuchs1, Jingjia Chen2,3, Oliver C Kiersnowski1, Russell Murdoch1, Chunlei Liu2,3, and Karin Shmueli1 | ||
1Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, United States, 3Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States |
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Keywords: Susceptibility, Quantitative Susceptibility mapping Here, we reproduced the results of the DECOMPOSE susceptibility separation model using new $$$T_2^*$$$-weighted data independently acquired using three clinically applicable sequences and processed with different QSM pipelines. This allowed us to investigate the sensitivity of DECOMPOSE to various dipole inversion algorithms. Good susceptibility source separation results were achieved using a 5-echo GRE acquisition, but maps of diamagnetic and paramagnetic sources from a highly accelerated 5-echo EPI sequence were noisy. When the input susceptibility maps exhibited artefacts, these were exacerbated by DECOMPOSE. Care must be taken not to lose local structural information when using (highly) regularised input susceptibility maps. |
| 4476 | Computer 42
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Evaluating High-Resolution High-b-value OGSE Time-dependent Diffusion in Human Brain at Ultra-high-gradient 3.0T |
| Ante Zhu1, Nastaren Abad1, Robert Y Shih2,3, Raymond Huang4, Chitresh Bhushan1, Tim Sprenger5, Jennifer A McNab6, J Kevin DeMarco2,3, Vincent Ho2,3, and Thomas K.F. Foo1,2 | ||
1GE Research, Niskayuna, NY, United States, 2Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 3Walter Reed National Military Medical Center, Bethesda, MD, United States, 4Brigham and Women's Hospital, Boston, MA, United States, 5GE Healthcare, Stockholm, Sweden, 6Stanford University, Palo Alto, CA, United States |
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Keywords: Microstructure, Diffusion/other diffusion imaging techniques Oscillating gradient spin echo (OGSE) time-dependent diffusion MRI has been shown to improve assessment of intra-cranial disease progression including glioma and multiple sclerosis. In human brain studies, however, high-resolution and high-b-value OGSE diffusion measurements suffer from low signal-to-noise ratio and Rician noise bias. In our preliminary studies with ultra-high-performance gradient 3.0T system, apparent diffusivity coefficient (ADC) of white matter at OGSE 35 Hz showed lower values when ADC was estimated from high b-values ≥1000 s/mm2 with 1.5-mm isotropic resolution, due to Rician noise bias. The effect of Rician noise bias on OGSE ADC measurement was reduced by using real-valued signals. |
| 4477 | Computer 43
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Investigating changes in brain lactate compartmentation using diffusion-weighted MRS in APP/PS1 mice |
| Sophie Malaquin1, Eloïse Mougel1, Rodrigo Lerchundi1, and Julien Valette1 | ||
1Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure Diffusion-weighted MR spectroscopy yields information about the microstructure of the environment where brain metabolites are diffusing. Here, we measure the diffusion of two purely intracellular metabolites (astrocytic myo-inositol and neuronal N-acetyl aspartate) and of lactate, which is also present in the extracellular space, in the cortex of 12-month-old APP/PS1 and control mice. While astrocytic and neuronal microstructures appear unchanged in APP/PS1 mice, lactate diffusion appears slower. Modeling DW-signals suggests decreased extracellular lactate fraction. |
| 4478 | Computer 44
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Estimating brain tissue stiffness from cardiac-induced 7T MRI displacement measurements |
| Marius Burman Ingeberg1, Elijah van Houten2, and Jaco Zwanenburg1 | ||
1UMC Utrecht, Utrecht, Netherlands, 2University of Sherbrooke, Sherbrooke, QC, Canada |
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Keywords: Image Reconstruction, Brain, Shear Stiffness, Tissue properties, Elastography, DENSE, 7T MRI Mechanical properties of the human brain can be altered by a variety of pathologies. These properties can be estimated from in vivo MRI measurements of brain tissue displacements as induced by the heartbeat. Previously obtained 7T MRI displacements measurements were used to reconstruct stiffness parameters using a subzone-based non-linear inversion scheme. Various structures of the brain can be observed in the reconstructed parameter distributions, and the results show good test-retest reliability. The preliminary results show promise of this approach to yield non-invasive assessment of brain tissue microstructure as a tool to investigate brain disease. |
| 4479 | Computer 45
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Diffusion spectrum imaging at 7T for probing Restricted compartment of Textile-based Phantom |
| Sudhir Kumar Pathak1, Yijen Wu2,3, Tony Zuccolotto4, and Walter Schneider1,5,6,7,8 | ||
1Learning Research and Development Center, University of Pittsburgh, Pittsburgh, PA, United States, 2Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA, United States, 3Rangos Research Center Animal Imaging Core, University of Pittsburgh, Pittsburgh, PA, United States, 4Psychology Software Tools, Pittsburgh, PA, United States, 5Psychology, University of Pittsburgh, Pittsburgh, PA, United States, 6Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, 7Neurosurgery, University of Pittsburgh, Pittsburgh, PA, United States, 8Radiology, University of Pittsburgh, Pittsburgh, PA, United States |
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Keywords: Phantoms, Quantitative Imaging, Diffusion MRI, microstructural imaging Validating mathematical models that describe the diffusion in the restricted compartment in biological tissue is an active research area. Techniques like NODDI, SMT, and CHARMED models claim to quantify restricted, hindered, and free water compartment but lacks validation on a typical clinical scanner. We present a 3D-printed phantom that uses (non)-water-filled textile-based hollow fiber with a 0.9μ diameter to validate restricted and hindered compartments. This study used a DSI-based scanning protocol and reconstruction method (GDSI and RDI) to probe the restricted compartment at a 2-6μ length scale. Scalar metrics derived from reconstruction methods show a significant difference between water-(un)filled taxons. |
| 4480 | Computer 46
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Investigating Diffusion Time Dependent Kurtosis Evolution in Repeated Mild Traumatic Brain Injury in Mice |
| Jake Hamilton1,2, Naila Rahman1,2, Kathy Xu3, Arthur Brown3,4, and Corey Baron1,2 | ||
1Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada, 2Centre for Functional and Metabolic Mapping (CFMM), Robarts Research Institute, University of Western Ontario, London, ON, Canada, 3Translational Neuroscience Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada, 4Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada |
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Keywords: Traumatic brain injury, Microstructure, mild Traumatic Brain Injury (mTBI); Concussion Probing the diffusion time dependence of diffusional kurtosis within brain microstructure is being recognized as a valuable method to study various neurological pathologies, however, its use in the study of repeated mild traumatic brain injury (mTBI) has not been explored. In this work, we investigated differences in the time-dependence of diffusional kurtosis in injured and sham mice using oscillating gradient spin echo (OGSE) diffusion kurtosis imaging (DKI). The results of this work show promising differences in kurtosis within the hippocampus of injured and sham mice, illustrating the sensitivity of OGSE DKI in detecting long-lasting pathological microstructural changes following brain injury. |
| 4481 | Computer 47
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Best Response Constraint Generative Adversarial Network for Diffusion MRI-based Estimation of Cortical micro-Architecture |
| Tianjia Zhu1,2, Minhui Ouyang1,3, Xuan Liu4, Risheng Liu4, and Hao Huang1,3 | ||
1Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, United States, 2Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 4School of Information Science and Engineering, Dalian University of Technology, Dalian, China |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure, machine learning/artificial intelligence, neuro Advanced diffusion MRI (dMRI) has enabled noninvasive assessment of conventional cortical histological measures. However, analytical models are limited by their restrictive model assumptions and lack of validation from quantitative histology. We have developed a Diffusion-MRI based Estimation of Cortical micro-Architecture (DECAM) method using a novel deep learning technique Best Response Constraint Generative Adversarial Network (BRC-GAN) for accurately estimating cortical soma density (SD) leveraging rich dMRI data information. By providing high-fidelity, reproducible whole-brain estimated SD maps validated with histology, DECAM paves the way for data-driven noninvasive virtual histology for potential applications such as Alzheimer’s diseases. |
| 4482 | Computer 48
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Diffusion filters, T2-filters, diffusion tensor component diffusivities, and compartmental diffusivities. What is happening in FEXI? |
| Hyeong-Geol Shin1,2, Xu Li1,2, Hye-Young Heo1, Linda Knutsson1,2,3, Filip Szczepankiewicz3, Markus Nilsson4, and Peter van Zijl1,2 | ||
1Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States, 3Department of Medical Radiation Physics, Lund University, Lund, Sweden, 4Deparment of Radiology, Clinical Sciences Lund, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques, FEXI, trans-membrane exchange We explored how compartmental anisotropy affects filter-exchange imaging (FEXI) data in white matter by applying different types of tissue water magnetization filters, including multi-orientation and spherical tensor encoded diffusion filters, as well as a T2 filter. The results show that, depending on the mutual orientation of the filter and detection gradient pairs relative to fiber orientation, filtering efficiencies can be positive or negative. We conclude that the fast compartment reduced during diffusional filtering need not be extracellular, but can also reflect intra-axonal signal losses with effect size determined by the diffusion tensor components perpendicular and parallel to the fibers. |
| 4483 | Computer 49
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G-ratio Calculation in Multiple Sclerosis: The Impact of Diffusion Modelling for Axonal and Fiber Volume Fraction Determination |
| Tigris Joseph1,2, Shannon H. Kolind1,2,3,4, Guojun Zhao3, Peng Sun5, Robert Carruthers3, Alice Schabas3, Ana-Luiza Sayao3, Virginia Devonshire3, Roger Tam4,6, G. R. Wayne Moore2,3,7, David K. B. Li3,4, Sheng-Kwei Song8, Anthony Traboulsee3, Irene M. Vavasour2,4, and Cornelia Laule1,2,4,7 | ||
1Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada, 3Medicine, University of British Columbia, Vancouver, BC, Canada, 4Radiology, University of British Columbia, Vancouver, BC, Canada, 5Imaging Physics, MD Anderson Cancer Center, Houston, TX, United States, 6School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada, 7Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada, 8Radiology, Washington University, St. Louis, MO, United States |
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Keywords: Multiple Sclerosis, White Matter, myelin, axons, g-ratio, brain, microstructure, lesions, normal appearing white matter, multiple sclerosis G-ratio is the ratio of the inner axonal diameter to the total outer diameter, including myelin. MRI-derived g-ratios in multiple sclerosis (MS) may convey microstructural tissue abnormalities. G-ratios were estimated using myelin water fraction scaled to myelin volume fraction, and axonal metrics from Diffusion Basis Spectrum Imaging (DBSI), Neurite Orientation Dispersion and Density Imaging (NODDI), Spherical Mean Technique (SMT), and ActiveAx for axon/fiber volume fraction in 122 MS patients. DBSI and ActiveAx derived g-ratios were higher in lesions than normal appearing white matter (NAWM), reflecting MS pathology. NODDI and SMT derived g-ratios were unexpectedly lower in lesions than NAWM. |
| 4484 | Computer 50
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A multi-compartment fingerprinting model for non-invasive tumor cell characterization via diffusion MRI |
| Manon Dausort1, Nicolas Delinte1,2, Quentin Dessain1, Colin Vanden Bulcke1,2, and Benoit Macq1 | ||
1ICTEAM, UCLouvain, Louvain-la-neuve, Belgium, 2IoNS, UCLouvain, Louvain-la-neuve, Belgium |
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Keywords: Microstructure, Tissue Characterization Brain tumor tissue characteristics are important for treatment planning but are nowadays often recovered via invasive biopsy analysis. This work attempts to characterize the microstructural properties of tumor cells using diffusion MRI and Monte Carlo simulations to build a dictionary composed of several fingerprints, combining both a representation of axonal fibers and tumor cells. We demonstrate the use of our method on in-vivo brain data as a reliable estimation of tumor cell properties. |
| 4485 | Computer 51
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Optimization method for estimating tissue microstructure size-distributions with diffusion weighted imaging |
| Pablo Javier Jimenez1,2, Analia Zwick1,2,3, and Gonzalo Alvarez1,2,3 | ||
1Centro Atómico Bariloche, CONICET, CNEA, Bariloche, Argentina, San Carlos de Bariloche, Argentina, 2Instituto Balseiro, CNEA, Universidad Nacional de Cuyo, Bariloche, Argentina, San Carlos de Bariloche, Argentina, 3Instituto de Nanociencia y Nanotecnologia,CNEA, CONICET, Bariloche, Argentina, San Carlos de Bariloche, Argentina |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure Characterization of microstructures in living-tissues by non-invasive imaging is one of the key and outstanding challenges for diagnosing early stages of pathologies and understanding disease mechanisms. Here we implement an optimal control strategy for obtaining microstructure details by Diffusion-Weighted Imaging sequences. We estimate microstructure parameters of size-distribution models for axon bundles, attaining the ultimate precision limits predicted by quantum-information tools. We performed proof-of-principle experiments of the optimization protocol with an ex-vivo mouse-brain contrasted with simulations. These results might drastically reduce the total acquisition time compared to the present state-of-the-art, opening alternative avenues towards unraveling diagnostic information by quantitative MRI. |
| 4486 | Computer 52
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Inter-subject variability in fiber orientation density function increases with aging |
| Hunter Moss1, Andreana Benitez2, and Jens Jensen1 | ||
1Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Neurology, Medical University of South Carolina, Charleston, SC, United States |
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Keywords: Tractography & Fibre Modelling, Microstructure The fiber orientation density function (fODF) estimated from diffusion MRI is typically used as an input for fiber tractography or microstructural modeling. However, since it encodes the fine details of the intra-voxel distribution of axon orientations, it can also be regarded as a quantity of physical interest that is potentially sensitive to subtle white matter changes. Here we demonstrate a method for quantifying inter-subject fODF differences in individual voxels within a white matter skeleton for a cohort of healthy older adults. We find that inter-subject fODF variability increases with age suggesting that diverse processes affect axons in healthy aging. |
| 4487 | Computer 53
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Assessing Sex Differences in the Brain’s White Matter Microstructure during Development using the Tensor Distribution Function |
| Sebastian M. Benavidez1, Katherine E. Lawrence1, Emily Laltoo1, James T. McCracken2, and Paul M. Thompson1 | ||
1Imaging Genetics Center, Mark and Mary Stevens Neuroimaging & Informatics Institute, University of Southern California, Marina del Rey, CA, United States, 2Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, United States |
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Keywords: Signal Modeling, Microstructure Diffusion magnetic resonance imaging (dMRI) can detect sex differences in developmental populations, as shown previously using the conventional diffusion tensor imaging (DTI) model. However, DTI cannot model complex brain fiber orientations, which the advanced tensor distribution function (TDF) model does. Here we compared the two models’ sensitivity in detecting sex differences, with the goal of improving our understanding of WM sex differences during development. We discovered WM microstructure sex effects, with the TDF model detecting more regions with significant differences and yielding larger effect sizes. Our results suggest that TDF is better able to detect developmental sex effects on WM. |
| 4488 | Computer 54
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Modelling transverse relaxometry using myelin-induced off-resonance fields and magnetisation transfer |
| Michiel Cottaar1 and Saad Jbabdi1 | ||
1Wellcome Center for Integrative Neuroimaging (WIN), University of Oxford, Oxford, United Kingdom |
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Keywords: Microstructure, Microstructure We present a new Monte Carlo MR simulator, which in addition to simulating the random diffusion of water restricted by any obstacles also simulates (1) the off-resonance field due to myelin and (2) signal loss due to magnetisation transfer. We use this simulator to study the interaction of diffusion, relaxation, and magnetisation transfer. We simulate gradient and spin echo measurements in white matter. The myelin off-resonance field is found to greatly reduce T2* due to dephasing of the signal between compartments, but barely affects T2. Magnetisation transfer at tissue boundaries explains T2 differences between intra-, extra-axonal, and myelin water. |
| 4489 | Computer 55
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Exploring the oscillating gradient waveform frequency dependence of diffusivity changes in human acute ischemic stroke |
| Mi Zhou1, Robert Stobbe1, Brian Buck2, Mahesh Kate2, Paige Fairall2, Derek Emery3, Thorsten Feiweier4, and Christian Beaulieu1 | ||
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, 2Neurology, University of Alberta, Edmonton, AB, Canada, 3Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada, 4Siemens Healthcare GmbH, Erlangen, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Microstructure Two previous oscillating-gradient-spin-echo (OGSE) studies of human acute ischemic stroke using different diffusion waveforms (40 Hz, one-period; 50 Hz, two-period) have reported considerably different mean diffusivity (MD) changes in lesion white matter relative to long diffusion time (“0 Hz”) pulsed-gradient-spin-echo (PGSE). Here both OGSE waveforms were acquired in 8 stroke patients. Lesions showed marked diffusion time dependencies with lesion MD reduction of 40% for PGSE compared to 25% for OGSE 40Hz, and yet OGSE 50Hz was only a bit less (21%). Large heterogeneity between patients (+6% to -43% of OGSE 50Hz MD lesion changes) may explain earlier study differences. |
| 4490 | Computer 56
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Evaluating frequency offsets due to local dephasing in magnetically inhomogeneous tissue |
| Ross Shaw1, Richard Bowtell1, and Penny Gowland1 | ||
1Physics, University of Nottingham, Nottingham, United Kingdom |
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Keywords: Simulations, Microstructure Through simulation the frequency offsets due to signal dephasing around biologically relevant local regions of high magnetic susceptibility are explored. Monte Carlo simulations are used to characterise the frequency offsets produced by spherical inclusions of varying radius and susceptibility in the presence of diffusion. The results indicate that heterogeneity of non-haeme iron concentration produce $$$\delta\Omega R^{2}/D$$$ values associated with local frequency offsets of up to $$$ -0.053 \gamma B_{0}\chi_{av}$$$: such offsets would be a confound for QSM measurements that merits further investigation. |
| 4491 | Computer 57
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Investigating Multi-Dimensional Diffusion-Weighted MRI for High-Resolution Post-Mortem Brain Acquisitions at 9.4 T |
| Hannah L. Gerbeth1,2, Michael Paquette1, Carsten Jäger3,4, Patricia Wenk5, Eike Budinger5, Markus Morawski3,4, and Cornelius Eichner1 | ||
1Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Translational Molecular Imaging, German Cancer Research Centre, Heidelberg, Germany, 3Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 4Paul Flechsig Institute - Center of Neuropathology and Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany, 5Combinatorial Neuroimaging Core Facility, Leibniz Institute for Neurobiology, Magdeburg, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques, ex vivo, human, brain Diffusion-weighted MRI (dMRI) is a widely used tool to non-invasively study the microstructure of the human brain. However, conventionally employed diffusion tensor imaging (DTI) applications only provide limited information. In contrast, Multi-Dimensional Diffusion Imaging, MD-dMRI, aims to provide a framework for further discrimination between highly complex biological structures. In this context, post-mortem MD-dMRI data play an important role to validate in vivo imaging results. Because the fixation process modifies tissue properties, adapted and optimized acquisition methods are required. Here, we investigate the feasibility to acquire and analyse high-resolution MD-dMRI data from a post-mortem brain tissue sample. |
| 4492 | Computer 58
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Optimization of non-uniform oscillating gradient spin echo sequences for selective microstructure-size imaging |
| Milena Capiglioni1,2,3, Analía Zwick1,2,4, and Gonzalo A. Álvarez1,2,4 | ||
1Instituto Balseiro, CNEA, Universidad Nacional de Cuyo, Bariloche, Argentina, 2Centro Atómico Bariloche, CONICET, CNEA, Bariloche, Argentina, 3Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Switzerland, 4Instituto de Nanociencia y Nanotecnologia, CONICET, CNEA, Bariloche, Argentina |
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Keywords: Diffusion/other diffusion imaging techniques, New Signal Preparation Schemes, NOGSE, Axon Diameter Diffusion-weighting imaging is a promising method for quantitative imaging of tissue microstructure features that may identify early stages of pathologies. Non-uniform oscillating gradient spin-echo (NOGSE) sequences are a novel technique to study diffusion spectra and quantitatively characterize tissue. The sequence contrasts the signal between two modulating gradient frequencies to filter the signal originating from molecules diffusion in specific restriction sizes. We determine the range of control parameters that maximizes NOGSE contrast for filtering the restriction sizes. We assess the restriction sizes that this sequence can filter with current technologies. |
| 4493 | Computer 59
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The Value of Neurite Orientation Dispersion and Density MR Imaging in Diagnosing Temporal Lobe Epilepsy with Hippocampal Sclerosis |
| Xiaonan Zhang1, Guohua Zhao1, Huiting Zhang2, Eryuan Gao3, and Jingliang Cheng1 | ||
1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2MR Scientific Marketing, Siemens Healthineers Ltd., Wuhan, China, 3The First Affiliated Hospital of Zhengzhou University,, Zhengzhou, China |
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Keywords: Quantitative Imaging, Brain The hippocampal microstructural alterations by using routine magnetic resonance imaging presents a challenge. This study aimed to evaluate the performance of the NODDI models in temporal lobe epilepsy (TLE) patients with hippocampal sclerosis (HS) by comparison with the routine Flair sequence. Our results found that all NODDI parameters had significant differences between ipsilateral HS and contralateral HS/HC, and had better diagnostic performance than Flair sequence. In addition, combined NODDI model had significant better diagnostic performance than all the single parameters. In conclusion, NODDI is superior to Flair image in diagnosing TLE with HS. |
| 4494 | Computer 60
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T1 Relaxation Anisotropy in White Matter is Directly Linked to the Axon Fibre Orientation in the Magnetic Field |
| Risto Kauppinen1, Jeromy Thotland2, Henri P.P. Leskinen3, Pramod K. Pisharady2, Eppu Manninen3, Mikko Kettunen3, Christophe Lenglet2, Olli H.J. Grohn3, Michael Garwood2, and Mikko J. Nissi3 | ||
1University of Bristol, Bristol, United Kingdom, 2University of Minnesota, Minneapolis, MN, United States, 3University of Eastern Finland, Kuopio, Finland |
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Keywords: Relaxometry, Contrast Mechanisms Interrelationships between T1 relaxation time and axon fibre orientation in midsagittal corpus callosum (CC) were studied in human brain in vivo at 3T and 7T as well as in a rat brain ex vivo at 9.4T. It was observed that in the same CC tracts in vivo the change in T1 results from altered fibre orientation with respect to B0. In the rat brain, ex vivo rotation of a given midsagittal CC ROI produced angular T1 plots that match those observed in vivo. Thus, axon fibre orientation is directly linked to T1 relaxation anisotropy. |
| 4495 | Computer 61
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Investigating Rb vapor density and temperature distributions in a high throughput 129Xe-Rb polarizer |
| James E. Ball1, Jim M. Wild1, and Graham Norquay1 | ||
1University of Sheffield, Sheffield, United Kingdom |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas) Accurate knowledge of the Rb vapor density, [Rb], is essential for optimizing 129Xe polarization (PXe) and production rates in clinical-scale 129Xe-Rb SEOP hyperpolarizers, used for hyperpolarized 129Xe MRI. We used atomic absorption spectroscopy to measure [Rb] for multiple Rb transitions to assess [Rb] measurement accuracy and extend [Rb] measurement range sensitivity. It was shown that [Rb] is significantly lower than saturation [Rb] and that [Rb] homogeneity was improved by implementing a larger Rb source distribution or a presaturator. The 129Xe-Rb spin-exchange cross section, $$$\gamma^\prime$$$, was determined to be $$$\gamma^\prime$$$= (1.2± 0.1) ×10−21m3s−1 for our operating conditions. |
| 4496 | Computer 62
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A novel compartmental model of 129Xe gas exchange using blind estimation of blood concentration |
| Yohn Taylor1, Geoffrey J. M. Parker1,2, Mina Kim1, and Pilar Jimenez-royo3 | ||
1Centre for Medical Image Computing, Quantitative Imaging Group, Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom, 2Bioxydyn Limited, Manchester, United Kingdom, 3GlaxoSmithKline, Stevenege, United Kingdom |
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Keywords: Hyperpolarized MR (Gas), Modelling, Blind deconvolution Preclinical to clinical translation of pulmonary gas exchange measurements utilising hyperpolarised 129Xe MRI is limited by the overlapping spectral peaks of dissolved 129Xe MR red blood cell (RBC) and tissue compartments in some preclinical species. We present a novel kinetic model of 129Xe exchange (KMXE) in conjunction with blind estimation techniques to evaluate 129Xe exchange between pulmonary tissue and blood without needing an explicit measurement of RBC signals. Using simulations, we show that kinetic parameter estimates are comparable to those estimated using conventional methods, demonstrating feasibility for evaluating gas exchange kinetics when no distinct RBC spectral peak can be measured. |
| 4497 | Computer 63
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The effect of variable compressed sense (CS) undersampling patterns in hyperpolarized Xenon (129Xe) diffusion-weighted MRI |
| Mitra Tavakkoli1,2, Sarah Svenningsen3,4, Yonni Friedlander4, Norm Konyer5, Parameswaran Nair3,4, and Michael D Noseworthy1,5,6,7 | ||
1Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada, 2Imaging Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada, 3Department of Medicine, McMaster University, Hamilton, ON, Canada, 4Firestone Institute for Respiratory Health, St Joseph’s Healthcare Hamilton, Hamilton, ON, Canada, 5Imaging Research Centre, St. Joseph’s Healthcare Hamilton, Hamilton, ON, Canada, 6Biomedical Engineering, McMaster University, Hamilton, ON, Canada, 7Department of Radiology, McMaster University, Hamilton, ON, Canada |
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Keywords: Image Reconstruction, Sparse & Low-Rank Models, Compressed Sensing, Lung, 129Xenon Compressed sensing is a fast-imaging technique capable of making high quality images with undersampled data. However, its application in hyperpolarized 129Xe diffusion-weighted MRI needs to be optimized. In this study, diffusion weighted images undersampled identically and differently, were compared with SNR, SSIM, mean ADC using repeated measures ANOVA. The application of different undersampling patterns for both diffusion-weighted and baseline images can result in ADC maps with higher quality, as compared to fully sampled equivalent parametric images. Thus, the baseline and diffusion-weighted images do not necessarily have the same optimum undersampling pattern, and optimization of each needs investigation separately. |
| 4498 | Computer 64
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Mapping transmit and receive B1 using variable flip angle acquisition on a person-by-person basis for hyperpolarized Carbon-13 and Xenon-129 MRI |
| Kylie Yeung1,2,3, Zack Ravetz1,4, Kher Lik Ng2,5, Gabriele AbuEid2, William Hickes2, Kenneth Jacob2, Mitchel Danisa2, Marianne Durrant2, Rebecca Mills1, Ayaka Shinozaki1,6, Jordan McGing1, Aaron Axford1, Sarah Birkhoelzer1, Rolf F Schulte7, Oliver Rider1, Anthony McIntyre2, Emily Fraser5, Damian J Tyler1,6, Fergus Gleeson2,8, and James T Grist1,2,6,9 | ||
1Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom, 2Department of Radiology, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 3Department of Oncology, Univeristy of Oxford, Oxford, United Kingdom, 4RRPPS, University Hospitals Birmingham, Birmingham, United Kingdom, 5Oxford Respiratory Service, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 6Department of Physiology, Anatomy and Genetics, Univeristy of Oxford, Oxford, United Kingdom, 7GE Global Research, Munich, Germany, 8Department of Oncology, University of Oxford, Oxford, United Kingdom, 9Alama Mater Studorium, University of Bologna, Bologna, Italy |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Non-Gas), Xenon-129, Carbon-13 Hyperpolarized MRI allows the imaging of processes such as gas exchange and metabolism. Calibration of transmit and receive (Tx/Rx) B1 is required to account for coil inhomogeneities in reconstruction. A variable flip angle (VFA) method, which is fast and readily implemented, allows for a simultaneous B1/T1 measurement. In this study, a mathematical model of VFA calibration was developed, tested, validated in a hyperpolarized Carbon-13 (13C) phantom and in vivo with hyperpolarized Xenon-129 imaging of human lungs. |
| 4499 | Computer 65
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Hybrid segmentation of ventilation defect regions in low signal-to-noise ratio hyperpolarized 129Xe MRI |
| Cheng Wang1,2, Sa Xiao1,2, Zimeng Li1,2, Haidong Li1,2, and Xin Zhou1,2 | ||
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, China, 2University of Chinese Academy of Sciences, Beijing, China |
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Keywords: Hyperpolarized MR (Gas), Lung Ventilation defect percentage (VDP) generated from hyperpolarized gas (3He or 129Xe) MRI is a sensitive indicator of lung disease. However, the commonly used K-means method for the calculation of VDP is not suitable for low signal-to-noise ratio (SNR) images. In this work, we proposed a hybrid segmentation method to segment the ventilation defect regions and calculate VDP values under low SNR conditions. The results show that the proposed method has improved both the accuracy of segmenting VDP map and calculating VDP value. |
| 4500 | Computer 66
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Healthy reference distributions for 129Xe gas exchange MRI with consideration of sex and hemoglobin |
| Aryil Bechtel1, David Mummy1, Junlan Lu2, Suphachart Leewiwatwong3, Joseph Mammarappallil1, Sakib Kabir1, and Bastiaan Driehuys1,2,3 | ||
1Radiology, Duke University, Durham, NC, United States, 2Medical Physics, Duke University, Durham, NC, United States, 3Biomedical Engineering, Duke University, Durham, NC, United States |
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Keywords: Hyperpolarized MR (Gas), Lung 129Xe gas exchange MRI is commonly quantified by binning images of ventilation, membrane uptake (M/gas), and red blood cell transfer (RBC/gas) according to thresholds established using healthy reference distributions. To date, reference values have been based on small samples and do not account for hemoglobin concentration (Hb), which is known to vary by sex. We apply a Hb correction to data from 15 young, healthy volunteers (age=25.2±3.3 yrs., 6 female). After correction, there was no significant difference in individual mean M/gas and RBC/gas between males and females. The resulting reference distributions have less dispersion and skew than previously established distributions. |
| 4501 | Computer 67
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Improving Xenon-129 Lung Ventilation Image Quality with a Commercial Deep-Learning Based Image Reconstruction |
| Neil J Stewart1, Jose de Arcos2, Alberto M Biancardi1, Jemima H Pilgrim-Morris1, Oliver I Rodgers1, Ryan S Munro1, Guilhem J Collier1, Graham Norquay1, Helen Marshall1, Anja Brau3, Marc Lebel4, and Jim M Wild1 | ||
1The University of Sheffield, Sheffield, United Kingdom, 2GE Healthcare, Cambridge, United Kingdom, 3GE Healthcare, San Francisco, CA, United States, 4GE Healthcare, Calgary, AB, Canada |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas) The utility of a deep learning based reconstruction tool for improving the quality of hyperpolarized 129Xe lung ventilation images was assessed. DL-reconstructed 129Xe ventilation image quality and SNR was improved compared with conventionally reconstructed images. In a cohort of patients with asthma and/or COPD, a small bias towards increased ventilation defect percentage, and a bias towards decreased coefficient of variation, in DL-reconstructed vs. conventionally-reconstructed images, was observed. Initial feasibility of utilising this tool for reduced-cost 129Xe ventilation imaging using natural-abundance xenon, and improved spatial resolution imaging with 129-enriched xenon, is demonstrated. |
| 4502 | Computer 68
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Terminal Airspace Enlargement Measured Using Pulmonary Functional MRI Predicts CT Airway Loss in COPD |
| Paulina Victoria Wyszkiewicz1,2, Maksym Sharma1,2, Harkiran K Kooner1,2, David G McCormack3, Miranda Kirby4, and Grace Parraga1,2,3,5 | ||
1Department of Medical Biophysics, Western University, London, ON, Canada, 2Robarts Research Institute, London, ON, Canada, 3Division of Respirology, Department of Medical Biophysics, Western University, London, ON, Canada, 4Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada, 5School of Biomedical Engineering, Western University, London, ON, Canada |
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Keywords: Hyperpolarized MR (Gas), Lung The onset and progression of chronic obstructive pulmonary disease (COPD) is currently believed to initiate in the small-airways and progresses to emphysema or terminal airspace (alveolar) enlargement and destruction. MRI apparent-diffusion-coefficient (ADC) provides a way to measure subclinical emphysematous destruction in patients. Here we investigated the relationship between pulmonary functional MRI measurements of terminal airspace enlargement using 3He MRI-ADC and CT airway changes in ex-smokers with COPD. MRI-ADC values at baseline were uniquely predictive of worsening CT total-airway-count and airway wall-area after three-years. MRI captures evidence of mild or subclinical emphysema and its relationship with terminal airway obliteration in COPD. |
| 4503 | Computer 69
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Effect of glucose on the HP 129Xe dissolved phase blood resonances |
| Lutoslawa Mikowska1, Vira Grynko2,3, Yurii Shepelytskyi3,4, Iullian Constantin Ruset5, Joseph Deschamps6, Hannah Aalto6, Marta Targosz-Korecka1, Hubert Harańczyk1, Dilip Balamore7, and Mitchell Albert3,4,8 | ||
1Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Kraków, Poland, 2Chemistry and Material Science Program, Lakehead University, Thunder Bay, ON, Canada, 3Thunder Bay Regional Health Research Institute, Thunder Bay, ON, Canada, 4Chemistry Department, Lakehead University, Thunder Bay, ON, Canada, 5Xemed LLC, Durham, NH, United States, 6Applied Life Sciences Program, Lakehead University, Thunder Bay, ON, Canada, 7Department of Engineering/Physics/Technology, Nassau Community College, Garden City, NY, United States, 8Northern Ontario School of Medicine, Sudbury, ON, Canada |
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Keywords: Hyperpolarized MR (Gas), Spectroscopy, blood, hemoglobin, dissolved phase imaging We examined the impact of elevated glucose levels on the chemical shift and T2* relaxation of hyperpolarized 129Xe dissolved in sheep blood. The addition of glucose did not affect the 129Xe-plasma resonance. For the first time, however, we have observed an additional 129Xe dissolved phase resonance attributed to 129Xe bound to glycated hemoglobin. A glucose-related linear downfield shift of the 129Xe resonance frequency was observed for 129Xe bound to native hemoglobin, whereas the T2* relaxation of 129Xe bound to glycated hemoglobin increased non-linearly with increasing glucose concentration. |
| 4504 | Computer 70
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Direct detection of polarization transfer from hyperpolarized 129Xe to thermally polarized 1H at 2 mT |
| Michele Kelley1, Nicholas Bryden1, Sebastian William Atalla1, and Rosa Tamara Branca1 | ||
1University of North Carolina at Chapel Hill, Chapel Hill, NC, United States |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas) We present a simple protocol for polarizing 1H at ultra-low field. By simply bubbling hyperpolarized Xe gas in a solution containing thermally polarized 1H spins, the proton thermal polarization can be enhanced by more than 100-fold. This enhancement is clearly observed, even in absence of saturation pulses, at ultra-low field where thermal polarization is close to background noise levels. Simultaneous detection of 1H and 129Xe magnetizations shows that the transfer of polarization from 129Xe to 1H spins is a continuous process that lasts until the dissolved-phase 129Xe polarization is relaxed back to thermal equilibrium. |
| 4505 | Computer 71
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Hyperpolarized 129Xe Magnetic Resonance Dual Signal Probe Based on CB[6] Nanoparticles for Precise Drug Delivery Monitoring |
| Chenlu Yuan1, Qianni Guo1, Qingbin Zeng1, Yaping Yuan1, Weiping Jiang1, Chaohui Ye1, and Xin Zhou1 | ||
1Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences – Wuhan National Laboratory for Optoelectronics, Wuhan 430071, P. R. China, WUHAN, China |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas), 129Xe，Hyper-CEST We synthesized an ultrasensitive 129Xe NMR probe with dual signals. It is a hollow nanoparticle composed of water-soluble CB[6]. It has two different hydrophobic cavities. Two 129Xe NMR signals with different chemical shifts can appear in a single detection, effectively avoiding the occurrence of false positive and false negative in complex biological environment detection, improving the accuracy and sensitivity of single detection, and has broad application prospects. |
| 4506 | Computer 72
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Batch-mode production of hyperpolarised xenon gas with a continuous-flow polariser for preclinical and clinical human lung ventilation images |
| Michael Vaeggemose1,2, Graham Norquay 3, Esben Søvsø Szocska Hansen1, Neil J. Stewart3, Oliver I. Rodgers3, Ryan S. Munro3, Rolf F. Schulte4, Guilhem J. Collier 3, Christoffer Laustsen1, and Jim M. Wild3 | ||
1MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark, 2GE Healthcare, Brøndby, Denmark, 3POLARIS group, University of Sheffield, Sheffield, United Kingdom, 4GE Healthcare, Munich, Germany |
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Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas), Lung ventilation imaging Hyperpolarised 129Xe gas was accumulated using spin-exchange optical pumping (SEOP) by continuous-flow of xenon gas directly from the cell without the use of cryogenic separation. 3D ventilation images were acquired in human and porcine models to determine clinical diagnostic image quality. Xenon ventilation image quality indicates that on demand batch production of xenon is feasible for both preclinical and clinical lung ventilation imaging examinations. |
| 4507 | Computer 73
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Repeatability of pulmonary 129Xe static spectroscopy and dynamic spectroscopy fit methods: a reader study |
| Aryil Bechtel1, Anna Costelle2, Elianna Bier3, Junlan Lu2, Joseph Mammarappallil1, Sakib Kabir1, David Mummy1, and Bastiaan Driehuys1,2,3 | ||
1Radiology, Duke University, Durham, NC, United States, 2Medical Physics, Duke University, Durham, NC, United States, 3Biomedical Engineering, Duke University, Durham, NC, United States |
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Keywords: Hyperpolarized MR (Gas), Heart, Lung 129Xe MRS measures static and dynamic spectral parameters from 129Xe signal in airspaces, membrane tissues, and red blood cells (RBC) and has the potential to characterize cardiopulmonary diseases. However, a better understanding of measurement repeatability is needed, and different approaches to quantifying cardiogenic oscillations have been proposed. Here, we compare quantification of oscillations using sine-fitting and a peak-finding algorithm and use reader ratings to identify acceptable study quality. Across a range of cardiopulmonary disease groups, measurements of static parameters showed good intra-session repeatability while the peak-finding algorithm generally yielded higher repeatability than sine fits for most dynamic parameters. |
| 4508 | Computer 74
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Chemical Shift Inversion Recovery (CSIR) spectroscopy with hyperpolarized xenon-129 MRI: A comparison with CSSR spectroscopy |
| Kai Ruppert1, Luis Loza1, Faraz Amzajerdian1, Hooman Hamedani1, Mostafa K Ismail1, Ryan J Baron1, Ian F Duncan1, Harrilla Profka1, Stephen Kadlecek1, and Rahim R Rizi1 | ||
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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Keywords: Hyperpolarized MR (Gas), Pulse Sequence Design Chemical shift saturation recovery (CSSR) MR spectroscopy using hyperpolarized xenon-129 provides metrics of pulmonary physiology by saturating the xenon dissolved-phase magnetization in the lung with a 90° RF pulse and measuring the subsequent signal recovery via gas exchange. Our measurements in a rat demonstrate that chemical shift inversion recovery (CSIR) spectroscopy, which replaces the saturation with an inversion pulse, produces equivalent results to CSSR but with greater robustness with respect to both low signal amplitudes at short delay times and incomplete saturation. |
| 4509 | Computer 75
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Assessing Ventilation Dynamics of Lung Transplantation with Free-Breathing Hyperpolarized Xenon-129 |
| Faraz Amzajerdian1, Hooman Hamedani1, Ryan Baron1, Mostafa Ismail1, Luis Loza1, Kai Ruppert1, Stephen Kadlecek1, and Rahim Rizi1 | ||
1Radiology, University of Pennsylvania, Philadelphia, PA, United States |
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Keywords: Hyperpolarized MR (Gas), Lung Regional quantification of ventilation dynamics can provide valuable insights into the functional changes associated with both unilateral and bilateral lung transplantation, potentially improving diagnostic monitoring and providing a better understanding of underlying pathophysiology. By imaging hyperpolarized xenon-129 (HXe) continuously over an extended period of time, ventilation dynamics more representative of steady-state, physiological breathing were derived and used to assess differences between unilateral and bilateral transplant patients. |
| 4510 | Computer 76
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Enhanced 129Xe T1 relaxation in blood and in presence of SPIONs at low field strengths |
| Nicholas Bryden1, Sebastian William Atalla1, Michele Kelley1, Leah R Holmes1, and Rosa Tamara Branca1 | ||
1Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States |
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Keywords: Hyperpolarized MR (Non-Gas), Relaxometry We demonstrate enhanced T1 relaxation of hyperpolarized 129Xe spins in blood and in the presence of superparamagnetic iron oxide nanoparticles (SPIONs) at low field strengths. |
| 4714 | Computer 121
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CASSAVA: a Compressed Adaptive SenSing Algorithm with Variable k‑space Averaging for high‑resolution volumetric 31P MRSI at 7T |
| Gino G. Rincon1,2, Philip S. Boyd1, Vanessa L. Franke1,2, Cornelius J. Bauer1,2, Mark E. Ladd1,2,3, Peter Bachert1,2, and Andreas Korzowski1 | ||
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany, 3Faculty of Medicine, University of Heidelberg, Heidelberg, Germany |
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Keywords: Non-Proton, Spectroscopy, Phosphorous MRSI Compressed sensing (CS) techniques suggest the feasibility of reducing the measurement duration of high‑resolution 31P‑MRSI at 7T to a clinically reasonable time (20 minutes) while preserving data quality. The proposed Compressed Adaptive SenSing Algorithm with Variable k‑space Averaging (CASSAVA) reconstructs 31P‑MRSI data with an undersampling factor of $$$R=3.8$$$ while simultaneously maintaining spectral peak accuracy and a high spatial resolution. This was demonstrated in the conducted simulation, retrospective, and prospective studies by evaluating the reconstructed spectra and intracellular pH maps of healthy and tumor tissues as a benchmark test. As a result, clinical research on larger patient cohorts becomes feasible. |
| 4715 | Computer 122
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Accelerated Enhanced Simultaneous Single-Quantum and Triple-Quantum-Filtered Sodium MRI Using Compressed Sensing at 7T |
| Qingping Chen1,2, Wieland A. Worthoff1, and N. Jon Shah1,3,4,5 | ||
1Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich GmbH, Jülich, Germany, 2Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 3Institute of Neuroscience and Medicine 11, Forschungszentrum Jülich GmbH, Jülich, Germany, 4JARA–BRAIN–Translational Medicine, Aachen, Germany, 5Department of Neurology, RWTH Aachen University, Aachen, Germany |
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Keywords: Non-Proton, Pulse Sequence Design, Multiple-quantum filtering; Sodium MRI Enhanced simultaneous single-quantum and triple-quantum-filtered imaging of 23Na (SISTINA) enables images to be weighted towards restricted sodium, a promising biomarker for clinical practice, but suffers from long acquisition times and low image quality. However, this can be alleviated by applying compressed sensing (CS). This work establishes a novel enhanced SISTINA sequence using FLORET sampling at 7T and demonstrates that CS can accelerate SISTINA acquisitions with less noise and better structure preservation than non-uniform fast Fourier transform while maintaining proper weightings towards total, non-restricted, and restricted sodium. The reduced acquisition time facilitates the clinical transition of enhanced SISTINA. |
| 4716 | Computer 123
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23Na Triple Quantum (TQ) Signal Estimation from Single-Pulse Sequence with Single Quantum (SQ) Time Efficiency |
| Simon Reichert1, Victor Schepkin2, Dennis Kleimaier1, and Lothar Schad1 | ||
1Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 2National High Magnetic Field Laboratory, Tallahassee, FL, United States |
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Keywords: Non-Proton, Non-Proton, Sodium, X-Nuclei, Triple-Quantum, TQ, new contrast mechanism This study demonstrates a method to estimate the biological relevant sodium TQ signal with a single-pulse sequence. Comparison of this method with theory and experiments using TQTPPI sequence showed a close agreement of the TQ signal. Therefore, the TQ signal can be estimated on the time scale of sodium SQ signal acquisition using the proposed sequence. |
| 4717 | Computer 124
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Dual responsive MR probe based on oxidation-triggered chemical shift |
| Natalia Ziolkowska1,2, Katerina Sulkova1, Lucie Kracikova3, Martin Vit1, Richard Laga3, and Daniel Jirak1 | ||
1Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic, 2First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czech Republic, 3Department of Polymer and Colloid Immunotherapeutics, Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czech Republic |
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Keywords: Non-Proton, Tumor Presented novel phosphorus- and fluorine-containing polymer possess high sensitivity at 31P/19F-MR and a large chemical shift from biological phosphorus signal (∆δ=60 ppm) due to phosphorothioate P=S group in its structure. The probe represents a conceptually new approach for phosphorus MR, as it undergoes oxidation-induced structural changes in the presence of ROS, represented in greater amounts in cancer tissue. The additional 19F-MR signal serve as an on-site information on the polymer distribution in the organism. |
| 4718 | Computer 125
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Solid state NMR in white matter: Unconventional 31P→1H cross polarization interrogates the proton pool |
| Alex Ensworth1,2, Cariad-Arianna Knight1, Piotr Kozlowski1,2,3,4, Cornelia Laule1,2,3,5, Alex L. MacKay1,3,4, and Carl A. Michal1 | ||
1Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada, 3Radiology, University of British Columbia, Vancouver, BC, Canada, 4UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, 5Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada |
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Keywords: Non-Proton, White Matter, myelin, phosphorus, hydrogen, spinal cord tissue, cross polarization, NMR, microstructure Tools to better characterize myelin health are urgently needed. We demonstrate the use of the solid-state NMR techniques cross polarization (CP) and WIdeline Separation (WISE) to directly probe the phosphorous (31P) of phospholipid myelin bilayers and characterize protons (1H) involved in CP. This work demonstrates the feasibility of unconventional CP from 31P→1H in porcine spinal cord and investigates the contributing 1H. The results of this work provide crucial insight into the characteristics exploitable by CP in myelin and reinforce the potential of a two-step transfer of semi-solid 31P signals into aqueous 1H, providing a more direct and myelin-specific MRI signal. |
| 4719 | Computer 126
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7-T 39K/23Na MRI for assessment of ionic balance in patients exhibiting hypokalemic periodic paralysis |
| Claudius Sebastian Mathy1,2, Armin Michael Nagel1,3, Matthias Türk4,5, Michael Uder1, Rafael Heiß1, Marc-André Weber6, and Lena Vanessa Gast1 | ||
1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States, 3Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 5Centre for Rare Diseases Erlangen (ZSEER), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 6Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany |
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Keywords: Non-Proton, Muscle, Potassium Combined 39K/23Na MRI at 7T has become feasible recently after technical advances of 39K MRI. Here we assessed ion homeostasis alterations, especially tissue potassium and sodium concentrations (TPC/TSC) in a small pilot cohort of patients of hypokalemic periodic paralysis (HypoPP). Depending on the severity of fatty involvement of muscles, TSC was elevated in slightly to moderately involved muscles and TPC showed a tendency to decrease in an inverse correlated fashion. Almost entirely fatty infiltrated muscle showed a decrease of TSC and TPC. Therefore, combined 39K/23Na MRI could help to examine the pathophysiological processes in HypoPP and other muscular channelopathies. |
| 4720 | Computer 127
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Spatially resolved assessment of 31P metabolite levels in liver metastases with 31P MRSI at 7T |
| Lieke van den Wildenberg1, Bobby Runderkamp2, Leonard Seelen1, Hanneke van Laarhoven3,4, Mark Gosselink1, Wybe van der Kemp1, Nadia Haj Mohammad5, Dennis Klomp1, and Jeanine Prompers1 | ||
1Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, 2Department of Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, 3Department of Medical Oncology, Amsterdam UMC, Amsterdam, Netherlands, 4Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, Netherlands, 5Department of Medical Oncology, Utrecht Medical Center Utrecht, Utrecht, Netherlands |
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Keywords: Non-Proton, Cancer Methods for early treatment response evaluation to systemic therapy of liver metastases are lacking. Tumor tissue is characterized by an increased PME/PDE ratio. However, with commonly used 31P surface coils for liver 31P MRS, the liver is not fully covered. Using an integrated 31P whole-body transmit coil in combination with a 16-channel body receive array at 7T, we were able to spatially map 31P metabolite levels throughout the whole liver in a patient with liver metastases. We found highly elevated levels of both PE/ATP and PC/ATP in liver metastases in comparison with healthy liver tissue. |
| 4721 | Computer 128
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23Na MRI at 21.1T reveals the Impact of Estrogen Deprivation in Preclinical Migraine |
| Dayna L. Richter1,2, Samuel Holder1,2, and Samuel Colles Grant1,2 | ||
1National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States, 2Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, United States |
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Keywords: Non-Proton, Neuro, Migraine, Extreme field Migraine disproportionately affects women in part due to menstrual migraine, linked to 17β-estradiol deprivation. This study implements 23Na MRI at 21.1 T in female Sprague-Dawley rats to evaluate the impact of estradiol deprivation on widespread sodium increases previously reported in the male model. Ovariectomy was implemented, and animals dosed with controlled estradiol to mimic the natural estrus cycle. It was found that females at physiological estradiol concentrations are resilient to sodium increases in the brainstem and CSF, while estradiol deprivation removes this resiliency. This interaction may play a role in menstrual migraine, and the clinical migraine gap between sexes. |
| 4722 | Computer 129
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Accelerated in-vivo 23Na Multi-Quantum Coherences MRI by utilizing Low-Rank Matrix Completion |
| Christian Licht1, Stanislas Rapacchi2, and Lothar R. Schad1 | ||
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, 2CRMBM, Aix-Marseille Université, Marseille, France |
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Keywords: Non-Proton, Multi-Contrast, Sodium Sodium (23Na) MRI has received increased attention as a potential biomarker for disease states thanks to the advent of ultra-high field MRI. One interesting asset from 23Na MRI is the distinction between single and triple quantum signal to further characterize tissues. However, 3D 23Na multi-quantum coherences (MQC) imaging requires multiple radiofrequency phase-cycling, which is inherently time-consuming and therefore difficult to include in protocols. In this work, we propose to accelerate 23Na MQC MRI by leveraging multi-dimensional under-sampling coupled with a dedicated Low-Rank matrix completion image reconstruction. |
| 4723 | Computer 130
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17O-MRI of the cerebral metabolic rate of oxygen during electrical stimulation of the paws in the rat at 11.7 T |
| Amelie Tourais1, Cameron Hery1, Martine Guillermier1, Julien Valette1, and Celine Baligand1 | ||
1Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France |
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Keywords: Non-Proton, Metabolism CMRO2 is an important metric for the evaluation of neurovascular and neurometabolic coupling. However, the degree of coupling between brain activity and CMRO2 remains a matter of debate. In this work, we used 17O-ZTE-MRI at 11.7 T to measure CMRO2 during neuronal activation in the rat primary somatosensory cortex. To improve measurements sensitivity, we acquired data over two consecutive cycles of 17O2 inhalation-washout. We show that a significant functional increase in CMRO2 (+7±5%, p=0.016), and in the rates of metabolized water gain and loss KG (+19±11%, p=0.18) and KL (10±6%, p=0.014) can be detected with good spatial resolution after summation. |
| 4724 | Computer 131
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Skin Sodium Concentration Measurement Increased with Surface-Coils, Higher Resolution Voxel Reshaping, and Lower Flip-Angles |
| Jingxuan Zhu1, Christian Beaulieu1, Karim Damji1, and Rob Stobbe1 | ||
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada |
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Keywords: Non-Proton, Body Non-proton (23Na) MRI studies have measured greater body tissue (skin) sodium concentration in disorders such as hypertension, diabetes, and chronic kidney disease, but literature values of ~15 mM are well below the 77 mM from atomic absorption spectroscopy. Previous studies have used gradient-echo imaging with long TE=2 ms, knee volume-coils, and large 3×3×30=270 mm3 voxels. Here, short TE=0.1 ms twisted projection imaging is used, and signal loss is progressively lowered with surface coil imaging, reshaped 0.4x4x4 = 6.4 mm3 voxels, and lower 60o flip-angle excitation, ultimately yielding 42 mM calf skin measurement in 10 young adults. |
| 4725 | Computer 132
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Optimisation of Simultaneously Acquired Single and Triple Quantum Filtered Sodium MRI for Relaxometry at 7T |
| Wieland A. Worthoff1, Qingping Chen1,2, and N. Jon Shah1,3,4,5 | ||
1Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich GmbH, Jülich, Germany, 2Faculty of Medicine, RWTH Aachen University, Jülich, Germany, 3Institute of Neuroscience and Medicine - 11, Forschungszentrum Jülich GmbH, Jülich, Germany, 4Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 5JARA-BRAIN - Translational Medicine, Jülich-Aachen Research Alliance, Aachen, Germany |
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Keywords: Non-Proton, Relaxometry, Sodium, Multiple Qunatum Filtering Sodium relaxometry has great potential value for research and clinical practice. Enhanced Simultaneously Acquired Single and Triple Quantum Filtered Imaging of Sodium (eSISTINA) can yield information on both fast and slow transversal relaxation times. The eSISTINA sequence is optimised by adding an early echo in the multiple-quantum-filtered readout train using FLORET k-space trajectories. The optimised sequence is compared and verified against a conventional, Cartesian multi-echo gradient echo based enhanced eSISTINA sequence on a group of four healthy volunteers. The experimental results show that the optimised sequence has better in vivo relaxometry performance than the conventional sequence. |
| 4726 | Computer 133
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Metabolic imaging of response to therapy in pediatric diffuse midline gliomas |
| Georgios Batsios1, Celine Taglang1, Meryssa Tran1, Anne Marie Gillespie1, and Pavithra Viswanath1 | ||
1University of California, San Francisco, San Francisco, CA, United States |
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Keywords: Non-Proton, Metabolism, preclinical, animals, brain, spectroscopy, deuterium Diffuse midline gliomas (DMGs) are lethal pediatric brain tumors. DMG patients are typically treated with radiation in combination with an experimental agent in clinical trials. ONC206 is a novel drug with promising efficacy in preclinical models. Successful clinical translation and deployment of ONC206 requires the identification of companion biomarkers of treatment response. Therefore, the goal of this study was to identify magnetic resonance spectroscopy (MRS)-detectable biomarkers of response to ONC206 in preclinical DMG models. Our studies identify a combination of 1H- and 2H-MRS-detectable biomarkers that serve as imaging biomarkers of early response to ONC206 in mice bearing intracranial DMG xenografts. |
| 4727 | Computer 134
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Quantitative sodium MRI of the human kidneys at 7T – Before, during and after water load via sliding window evaluation |
| Anna K. Scheipers1,2, Armin M. Nagel1,3, Laurent Ruck3, Lena V. Gast3, Mark E. Ladd1,2,4, and Tanja Platt1 | ||
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3University Hospital Erlangen, Institute of Radiology, Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU), Erlangen, Germany, 4Faculty of Medicine, Heidelberg University, Heidelberg, Germany |
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Keywords: Non-Proton, High-Field MRI, Kidney, Quantitative Imaging 23Na-MRI is a non-invasive tool for the in-vivo quantification of the tissue sodium concentration (TSC); however, it suffers from low in-vivo signals and short relaxation times. High magnetic field strengths, dedicated hardware and pulse sequences as well as various correction methods contribute to obtaining reliable TSCs. In the presented work we employ a custom-built coil and reference vial setup and perform T1, B1+ and B1- corrections that were validated in phantom measurements. We use a sliding window reconstruction for the quantitative 23Na-images to investigate the changes in the TSC before, during and after a water load in two healthy volunteers. |
| 4728 | Computer 135
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Combining Extreme Narrowing and Slow Motion Regime in a Simple Motional Model for Sodium NMR Environment. |
| Simon Reichert1, Victor Schepkin2, Dennis Kleimaier1, and Lothar Schad1 | ||
1Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 2National High Magnetic Field Laboratory, Tallahassee, FL, United States |
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Keywords: Non-Proton, Non-Proton, Sodium, X-Nuclei, Very-High B-Field This study investigates a model of ion motion that is compatible with 23Na T1 and T2 mechanism of relaxation and even works with quasi mono-exponential T1. We compare this model with the commonly used Debye model using agar as a tissue model system at 9.4T and 21.1T. |
| 4729 | Computer 136
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Comparison of short and long TR Gradient Recalled Echo (GRE) measures for total sodium concentration mapping in the calf |
| Ben Prestwich1 and Susan Francis1 | ||
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom |
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Keywords: Non-Proton, Non-Proton, sodium MRI, T1 mapping, muscle, tissue sodium concentration Sodium (23Na) MRI measures of tissue are SNR limited. Here, we compare a 3D gradient recalled echo (GRE) 23Na scans with a short TR and fully recovered TR for estimation of tissue sodium concentration (TSC) in the calf. We validate measures by collecting 23Na T1 measures of the calf and reference bottles. A short TR scan is shown to provide increased image SNR, resulting in higher measures of TSC, along with improved depiction of the skin. Using the short TR GRE scan, older subjects and haemodialysis patients are shown to have higher calf TSC than younger subjects. |
| 4730 | Computer 137
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Reproducibility of 7T human cardiac 3D 31P-MRSI using concentric ring k-space trajectories (CRT). |
| Ferenc E Mózes1, William T Clarke2, and Ladislav Valkovič1,3 | ||
1Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom, 2Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 3Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia |
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Keywords: Non-Proton, Heart, phosphorus Cardiac 31P-MRS provides insight into metabolism of the failing heart. The commonly employed 3D-MRSI acquisitions are rather slow, even at 7T. Fast readout trajectories, such as concentric ring (CRT) have been recently suggested to substitute the slow Cartesian sampling (CSI), however their repeatability is yet unknown. Our preliminary data suggest comparable intra-session repeatability, but somewhat lower inter-session repeatability for mid septal voxels using 2.5 min CRT in comparison to 6.5 min CSI. Similar trends were observed for higher resolution CRT. |
| 4731 | Computer 138
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Analysis of regional differences in pH values obtained via 31P MRSI at 7T |
| Justyna Platek1,2, Florian Kroh1,2, Vanessa L. Franke1,2, Philip S. Boyd1, Nina Weckesser3, Heinz-Peter Schlemmer3,4, Daniel Paech3,5, Mark E. Ladd1,2,4, Peter Bachert1,2, and Andreas Korzowski1 | ||
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidleberg, Germany, 2Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany, 3Division of Radiology, German Cancer Research Center (DKFZ), Heidleberg, Germany, 4Faculty of Medicine, University of Heidelberg, Heidelberg, Germany, 5Division of Neuroradiology, University Hospital Bonn, Bonn, Germany |
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Keywords: Non-Proton, Spectroscopy, Phosphorus, pH, cancer In this study, we analyzed pH values obtained via high-resolution 31P MRSI at 7T in different subjects and different regions of the human brain, and identified a trend towards lower pH values in the frontal region compared to other brain regions. The potential regional variation should be taken into account in cases, where only small pH changes between different tissues are expected and partial volume effects might dominate. |
| 4870 | Computer 101
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Arbitrary Level Contrast Dose Simulation in Brain MRI Using Iterative Reconstruction with Transformer Models. |
| Dayang Wang1, Srivathsa Pasumarthi1, and Ryan Chamberlain1 | ||
1Subtle Medical Inc., Menlo Park, CA, United States |
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Keywords: Simulations, Data Acquisition, MRI Dose Simulation In Gadolinium-based contrast agents (GBCAs) assisted MRI scans, dose simulation is a significant task that enables understanding of the perfusion process. In this work, we propose a new transformer-based iterative model to generate MRI images with arbitrary contrast dosages. By using datasets where only 0%, 10%, and 100% dose images are available, the proposed model can synthesize quantitatively and qualitatively accurate MRI images of varying dosages. The simulated images can be used for other downstream tasks like developing reduced-dose acquisitions and finding the minimum dose needed for a given pathology. |
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Computer 102
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Imaging arterial and venous vessels using Iron Dextran enhanced multi-echo susceptibility weighted imaging (SWI) MRI at 7T |
| Yinghao Li1,2,3, Adrian Paez2,3, Di Cao1,2,3, Chunming Gu1,2,3, Kaihua Zhang2,3, Xinyuan Miao2,3, Jay Pillai4,5, Peter M van Zijl3,6, Christopher Earley7, Xu Li2,3, and Jun Hua2,3 | ||
1Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Department of Neurology, Johns Hopkins University School of Medicine, Baltimtore, MD, United States, 6F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimtore, MD, United States, 7Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States |
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Keywords: Contrast Agent, Blood vessels Iron Dextran is a widely used FDA-approved ultra-small-superparamagnetic-iron-oxides (USPIO) to treat iron deficiency anemia in patients. Here, we evaluate the feasibility of using Iron Dextran as an MRI contrast agent for imaging arterial and venous blood vessels using multi-echo susceptibility weighted imaging (SWI) MRI at 7T. Phantom experiments were performed to measure relaxivity values (r1 and r2) for Iron Dextran in blood. Pre- and post-infusion MRI images were acquired in human subjects from which maps of arteries and veins were extracted. The post-contrast SWI images showed enhanced susceptibility difference between blood and the surrounding tissue in both arteries and veins. |
| 4872 | Computer 103
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Dependency of R2 and R2* on Gd-DTPA Concentration: From Whole-Blood to Realistic Brain Tumor Vasculature |
| Daniëlle van Dorth1, Ahmad Alafandi2, Krishnapriya Venugopal2, Aurélien Delphin3, Dirk H. J. Poot2, Thomas Christen3, Marion Smits2,4,5, Jeroen de Bresser6, Juan Hernandez Tamames2, and Matthias J. P. van Osch1,4 | ||
1C. J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Radiology and Nuclear Medicine, Erasmus University Medical Center, Rotterdam, Netherlands, 3University Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France, 4Medical Delta, Delft, Netherlands, 5Brain Tumor Center, Erasmus MC Cancer Institute, Rotterdam, Netherlands, 6Radiology, Leiden University Medical Center, Leiden, Netherlands |
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Keywords: Simulations, DSC & DCE Perfusion In quantitative DSC-MRI, the concentration-time course is obtained from the MR signal changes following a bolus injection of contrast agent. The generally assumed linear relationship between ΔR2* and contrast agent concentration is not always valid. In this study a realistic 3D simulation model was used to establish the characteristics of this relationship in whole-blood and brain tumor tissue. The results show an improved performance of the 3D simulation model compared to its 2D version. In addition, the relationship between ΔR2* and contrast agent concentration appeared to be dependent on the B0 direction and MR sequence. |
| 4873 | Computer 104
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Ultra-high Moment Gold-coated Iron Particles Allows for Longitudinal Time-lapse MRI of Individual Stem Cells in the Brain |
| Nikorn Pothayee1, Stephen Dodd1, Li Liu1, Gary Zabow2, and Alan Koretsky1 | ||
1National Institutes of Health, Bethesda, MD, United States, 2National Institute of Standards and Technology, Boulder, CO, United States |
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Keywords: Contrast Agent, Cell Tracking & Reporter Genes In this study, gold coated microfabricated gold-coated iron particles are used for in vitro and in vivo labeling of immune cell and neural precursors, respectively for MRI. These particles have a pure iron core and protective layer of gold and exhibit extremely high magnetic moment relative to more commonly used, chemically synthesized, iron-oxide based particles. Following in situ labeling of neural precursor cells, we show that the migration of a large pool of individual cells can be visualized in time-lapse and longitudinal MRI. |
| 4874 | Computer 105
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A Novel Iron-oxide-based T1 Contrast Agent outperforms Gd-DOTA for Magnetic Resonance Lymphography |
| Yeon Ji Chae1, Mi-hyun Kim2,3, Chul-Woong Woo4, Sang-Tae Kim4, Do-Wan Lee5, Hwon Heo1, Monica Young Choi4, Yoonseok Choi6, Kyung Won Kim1,4, and Dong-Cheol Woo1,4 | ||
1Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, 2Department of Radiation Science & Technology, Jeonbuk National University, Jeonbuk, Korea, Republic of, 3Trial Informatics. Inc, Seoul, Korea, Republic of, 4Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea, Republic of, 5Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, 6Medical Research Institute, Gangneung Asan Hospital, Gangneung-si, Gangwon-do, Korea, Republic of |
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Keywords: Contrast Agent, Contrast Agent, Magnetic resonance lymphography, Iron-oxide-based T1 contrast agent The novel iron-oxide-based T1 contrast agent may be an optimal contrast agent for MR lymphangiography, because it enhances the lymphatics only without venous contamination for more than 1 hour. It can overcome the limitations of gadolinium-based contrast agents such as venous contamination and rapid washout. |
| 4875 | Computer 106
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Towards cell-size and switchable magnetocaloric MRI contrast agents using micofabricated thin-film FeRh. |
| Stephen Dodd1, Natalia Gudino1, O Zadorozhnii2, M Staňo2, J Hajduček2, J. A. Arregi2, Vojtech Uhlíř2, H. Doug Morris3, Mladen Barbic4, and Alan Koretsky1 | ||
1Laboratory of Functional and Molecular Imaging, NINDS, National Institutes of Health, Bethesda, MD, United States, 2Ceitec Magnetism, Central European Institute of Technology, Brno, Czech Republic, 3Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 4NYU Langone Health - Tech4Health Institute, New York, NY, United States |
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Keywords: Contrast Agent, Cell Tracking & Reporter Genes, Magnetocaloric material We present progress towards smaller magnetocaloric samples, that drastically change magnetic moment and hence T2* contrast when switched with external magnetic field or temperature, with the eventual goal of achieving a size appropriate for cell tracking. To that end a FeRh sample was microfabricated with a thickness of 200 nm, and patterned with varying linear dimensions from 500 micron down to 1 micron square. We demonstrate that this sample may be switched with temperature and with external field through imaging at 4.7 and 11.7T and with the application of pulsed B0 insert coil. |
| 4876 | Computer 107
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A new class of easily synthesized manganese contrast agents for liver MRI |
| Sean William McRae1, Michael Cleary2, Francisco Martinez3, Ying Xia3, Peter Caravan2, Eric Gale2, John Ronald3, and Timothy Scholl3 | ||
1Medical Biophysics, Western University, London, ON, Canada, 2Massachusetts General Hospital, Boston, MA, United States, 3Western University, London, ON, Canada |
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Keywords: Contrast Agent, Molecular Imaging This work investigated the performance of a novel class of Mn(II) T1 contrast agents made from a commercially available chelator with various lipophilic targeting moieties added to promote uptake through the human derived OATP1B1 and OATP1B3 transporters. Agent performance was assessed in vitro using cells engineered to express the human OATPs, and in vivo by assessing liver uptake in mice where other OATP isoforms are present. In vitro measurements suggested targeting of agents to human OATPs where in vivo imaging revealed strong contrast enhancement in murine livers, with no evident toxicity at a 0.1 mmol/kg dose. |
| 4877 | Computer 108
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Resting perfusion measures in patients with steno-occlusive disease; comparing two contrast agents Gadolinium and hypoxia-induced dOHb |
| Ece Su Sayin1, Vittorio Stumpo2, Jacopo Bellomo2, Julien Poublanc3, Marco Piccirelli4, James Duffin1, Vepeson Wijeya 3, Athina Pangalu4, Andrea Bink4, Bence Nemeth 4, Zsolt Kulcsar4, David John Mikulis3, Joseph Arnold Fisher1, Olivia Sobcyzk 3, and Jorn Fierstra 2 | ||
1Physiology, University of Toronto, Toronto, ON, Canada, 2Department of Neurosurgery, University Hospital Zurich, Zurich, Switzerland, 3University Health Network, Toronto, ON, Canada, 4Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland |
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Keywords: Contrast Agent, Perfusion Dynamic susceptibility contrast perfusion imaging is clinically acquired using Gadolinium based contrast agents (GBCA), however, there remain many drawbacks. We show that in patients with steno-occlusive disease perfusion imaging using hypoxia-induced dOHb have a high degree of similarity to those obtained using GBCA. |
| 4878 | Computer 109
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Relaxometry Measurements of Europium-doped Mn0.6Zn0.4Fe2O4 at Increasing Magnetic Field |
| Hamidreza saeidi 1,2, Morteza Mozaffari2, Serhat Ilbey1, Jochen Leupold1, and Michael Bock1 | ||
1Division of Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany, 2Faculty of Physics, University of Isfahan, Isfahan, Iran (Islamic Republic of) |
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Keywords: Contrast Agent, Relaxometry, Relaxometery, longitudinal Relaxation Time Magnetic resonance imaging (MRI) contrast agents with both intrinsic high r1 and r2 relaxivities are desirable in medical diagnosis to achieve highly accurate and ambiguity-free MR images. Here, we report synthesis and MRI tests of Europium doped Mn-Zn ferrite (EuMZF) nanoparticles at different magnetic field strengths. EuMZF nanoparticles showed significant improvement in both positive (T1) and negative (T2) contrasts. The results showed that by increasing magnetic field, r1 relaxivity decreased while r2 increased so that the EuMZF is suitable as a dual-mode contrast at 1.5 and 3T but it is a T2 agent at 7 and 9.4T. |
| 4879 | Computer 110
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Molecular Weight of Sugar Structures impacts Shielding Effect of Gd-Ions in Polysaccharides. |
| Patrick Werner1,2, Matthias Taupitz2, Sophia Ber3, and Leif Schröder1 | ||
1German Cancer-research center (DKFZ), Heidelberg, Germany, 2Charite Berlin, Berlin, Germany, 3Universität Heidelberg, Heidelberg, Germany |
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Keywords: Contrast Agent, Relaxometry, GBCA, gadolinium, long-term deposition, GAGs, dextran sulfate Detailed biochemical information on the long-term deposition of Gd3+ in the body after administration of GBCAs is still missing. Glycosaminoglycans should be considered as chelators of released Gd3+. We used dextran-sulfate to study the effect of polysaccharides with different molecular weights on the observable relaxivity. Chelation was observed through an increase in relaxation. Moreover, a molecular weight-specific shielding revealed by subsequent reduced R1 occurs at higher polysaccharide/Gd-ion ratios. This coincided with observations of Gd-induced aggregation. Similar shielding of re-chelated Gd3+can lead to an underestimation of deposited Gd-ions in the body and requires further research. |
| 4880 | Computer 111
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First Results of Novel Contrast Agent Based on Ultrasmall Paramagnetic Nanoparticles for T1-Weighted MRI |
| Khallil Taverna Chaim1, Mayara Klimuk Uchiyama1,2, Robson Raphael Guimaraes2, Koiti Araki2, and Claudia da Costa Leite 1 | ||
1School of Medicine - Radiology, University of Sao Paulo, Sao Paulo, Brazil, 2Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil |
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Keywords: Contrast Agent, Contrast Agent, nanoparticles MRI is one of the best imaging techniques in clinical analysis because it is non-invasive and has high resolution. Contrast agents are used to further improve these images, as they increase the level of soft tissue detail, differentiating regions of interest. Currently, Gd-based contrast agents have important precautions. In this work we present a new nanoparticle based on iron oxide, with 4 nm and positive contrast (T1-weighted). Thus, effects similar to gadoteric acid, with reduced signal persistence and partial renal excretion, indicating great stability, this new paramagnetic nanoparticle has great potential to be applied as a contrast agent in MRI. |
| 4881 | Computer 112
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Robust in vivo MRI of OATP reporter gene expressing cells using standard clinical dose of MRI contrast agent |
| Tapas Bhattacharyya1, Jeremy M.-L. Hix1, Christiane L. Mallett1, and Erik M. Shapiro1 | ||
1Radiology and Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, United States |
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Keywords: Molecular Imaging, Cell Tracking & Reporter Genes Hepatic OATPs are a promising molecular imaging reporter gene for MRI yet its translation for human studies is limited by the reported extremely high dose of contrast agent required (>40x clinical dose) for robust detection of engineered cells in vivo. Here we describe studies that culminated in the in vivo MRI detection of OATP-overexpressing cells using standard clinical doses. OATP-overexpression was accomplished by lentiviral transduction of tumor cells, followed by MRI screening to determine the best performing OATPs. In vivo MRI of OATP-overexpressing tumors was accomplished using a combination of both T1-weighted and dynamic contrast enhanced (DCE-) MRI. |
| 4882 | Computer 113
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Monitoring triple negative breast cancer therapy against lncRNA MANCR with MT218, a targeted MRMI contrast agent |
| Calin Nicolescu1, Da Sun1, Songqi Gao1, and Zheng-Rong Lu1,2 | ||
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 2Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States |
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Keywords: Molecular Imaging, Cancer, Breast Developing new molecular targeted therapies for triple negative breast cancer remains an obstacle. MANCR is a long noncoding RNA overexpressed in TNBC that sustains aggressive breast cancer growth. Silencing its expression with siRNA nanoparticles suppresses tumor growth, and treatment efficacy can be assessed by MRMI with a targeted contrast agent, MT218. Reduction in contrast-to-noise ratio following treatment confirmed effectiveness of siRNA therapy and allowed regular monitoring of tumor inhibition. RNA therapy shows promise as a new approach for treating aggressive breast cancer, and MRMI with the targeted contrast agent is a non-invasive imaging tool for TNBC detection and therapeutic surveillance. |
| 4883 | Computer 114
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Relaxation Rate MR Contrast of Metal-Organic Framework or USPIO Labelled Melt Electrowritten Polycaprolactone Scaffolds |
| Geoffrey J. Topping1, Salma Mansi2, Kilian M. A. Müller2, Zahid Hussain3, Sarah Dummert3, Carolin Rickert4, Sebastian P. Schwaminger5, Younzhe Zou2, Diana M. Rojas-González2, Sonja Berensmeier5, Oliver Lieleg4, Roland Fischer3, Petra Mela2, and Franz Schilling1 | ||
1Department of Nuclear Medicine, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, 2Medical Materials and Implants, Department of Mechanical Engineering, TUM School of Engineering and Design, & Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany, 3School of Natural Sciences and Catalysis Research Center, Technical University of Munich, Garching, Germany, 4Biomechanics, Department of Materials Engineering, TUM School of Engineering and Design, Technical University of Munich, Garching, Germany, 5Chair of Bioseparation Engineering, School of Engineering and Design, Technical University of Munich, Garching, Germany |
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Keywords: Contrast Mechanisms, Preclinical, Tissue Engineering Polycaprolactone scaffolds were melt electrowritten with and without included metal-organic frameworks (MOF) or nanoparticles (USPIO). MR images and relaxation rate (R1, R2, R2*) maps were acquired of scaffolds in agar and blood. Pure polycaprolactone showed weak or no contrast. Addition of MOF or USPIOs produced strong T2* contrast. Tensile properties were preserved up to 0.2 w/w% USPIOs. MOFs produced strong w/w% dependent antibacterial effects when included in scaffolds. |
| 4884 | Computer 115
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Engineering novel functional brain imaging contrast agents via iron oxide encapsulation in human red blood cells |
| Elizabeth Jane Fear1,2, Antonella Antonelli1, Pasant Abdalla1, Elisa Zamboni3, Marie-Christine Labarthe-Last2, Victoria Annis2, Simon Benedict Duckett2, Mauro Magnani1, and Aneurin James Kennerley2,4 | ||
1Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy, 2Centre for Hyperpolarisation in Magnetic Resonance (CHyM), Chemistry, University of York, York, United Kingdom, 3Psychology, University of York, York, United Kingdom, 4Sport and Exercise Science, Institute of Science, Manchester Metropolitan University, Manchester, United Kingdom |
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Keywords: Contrast Agent, Contrast Agent, red blood cells, Super Paramagnetic Iron Oxide Nanoparticles We have developed a next generation, safe, personalised iron-based contrast agent (CA) for empowering functional Magnetic Resonance Imaging (fMRI). Our proprietary method uses state-of-the-art red blood cell (RBC) encapsulation technology to engineer biocompatible super-paramagnetic CAs able to withstand rapid clearance from the bloodstream by macrophages (as part of the mononuclear phagocytic/reticuloendothelial system). The agent is validated in a multi-modal (concurrent fMRI and intrinsic optical imaging) preclinical rat model as a novel CA for the mapping of cerebral blood volume (CBV) in response to somatosensory stimulation, providing a non-BOLD alternative for accurate, high-resolution mapping of brain function. |
| 4885 | Computer 116
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High Longitudinal and Transverse Relaxivities with Rare Earth ions doped Mn0.6Zn0.4Fe2O4: a Potential for dual-mode Contrast Agents |
| Hamidreza saeidi 1,2, Morteza Mozaffari2, Serhat Ilbey1, and Michael Bock1 | ||
1Division of Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany, 2Faculty of Physics, University of Isfahan, Isfahan, Iran (Islamic Republic of) |
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Keywords: Contrast Mechanisms, Contrast Agent, Relaxometery, longitudinal Relaxation Time MRI contrast agents have gained extensive attention for providing contrast between normal and abnormal tissue. However, single-mode contrast agents do not always provide the required contrast enhancement for disease detection. One effective strategy for avoiding ambiguous images is to design MRI contrast agents with simultaneous T1 and T2 shortening effects. The purpose of this work is to synthesize rare earth ions doped Mn-Zn ferrite (ReMZF) nanoparticles and characterize them with a 1.5T MRI scanner in vitro. The ReMZF exhibited high r1 and r2 relaxivities but moderate r2/r1 which make them suitable to be used as dual-mode contrast agents. |
| 4886 | Computer 117
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A dedicated arterial input function compensating for inflow and partial voluming in dynamic contrast enhanced MRI |
| Chih-Hsien Tseng1, Martijn Nagtegaal1, Jaap Jaspers2, Alejandra Mendez Romero2, Piotr Wielopolski3, Marion Smits3,4, Matthias J.P. van Osch4,5, and Frans Vos1,3,4 | ||
1Imaging Physics, Delft University of Technology, Delft, Netherlands, 2Radiation Oncology, Erasmus MC Cancer Institute, University Medical Center, Rotterdam, Netherlands, 3Radiation and Nuclear Medicine, Erasmus MC, University Medical Center, Rotterdam, Netherlands, 4Medical Delta, Delft, Netherlands, 5Radiology, C.J. Gorter MRI center, Leiden University Medical Center, Leiden, Netherlands |
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Keywords: Contrast Mechanisms, DSC & DCE Perfusion Both inflow and partial volume effects (PVE) are sources of error when measuring the arterial input function (AIF) in DCE-MRI. We proposed a method that estimated the perceived pulse number of spins, and then corrected with these such that both effects were simultaneously compensated. Simulation data demonstrated that the reconstructed AIFs showed only marginal bias. In addition, the algorithm yielded highly correlated reconstructed curves over a wide range of PVEs in clinical data. Our findings show that the PVE can be compensated by considering it as part of the inflow correction as it exhibits similar confounding effects when measuring DCE-AIFs. |
| 4887 | Computer 118
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A MMP-Responsive Nanoplatform with Transformable Magnetic Resonance Property for Quantitative Tumor Bioimaging and Synergetic Therapy |
| Zhongling Wang1, AN CHEN1, Hongwei Lu2, and Xiance Zhao3 | ||
1Shanghai General Hospital，School of Medicine ，Shanghai jiaotong University, Shanghai, China, 2Lthink Medical Institute, Guangzhou, China, 3Philips Healthcare, Shanghai, China |
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Keywords: Molecular Imaging, Multimodal We developed a novel nanoplatform-based MMP9-responsive T2–T1 switching MRI contrast agent, which can be used not only for non-invasive visualization and quantitative analysis of MMP9 activity, but also as a carrier in photothermal sensitization chemotherapy. The nanoplatform acts as a T2 contrast agent in physiological conditions ,then transform into a T1 contrast agent by MMP9 stimulus. We have demonstrated that the changes R1 and R2/R1 values are MMP9 concentration dependent in tumors. The combination of PMPSD with laser irradiation was more effective than single chemo-/photothermal therapy, and up-regulation of MMP9 in the tumor could eanhance the nanoplatform’s therapeutic effect. |
| 4888 | Computer 119
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The magnetic resonance characteristics of SPIONs for imaging at ultralow field (6.5 mT) |
| Sheng Shen1, David E. J. Waddington2, Marie Zhang3, and Matthew S. Rosen1,4,5 | ||
1MGH/A. A. Martinos Center for Biomedical Imaging, Boston, MA, United States, 2The University of Sydney, Sydney, Australia, 3Imagion Biosystems, Ltd, San Diego, CA, United States, 4Department of Physics, Harvard University, Cambridge, MA, United States, 5Harvard Medical School, Boston, MA, United States |
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Keywords: Contrast Agent, Modelling Characterization of the parameters of superparamagnetic iron oxide nanoparticles (SPIONs) can guide synthesis of optimized particles for use in magnetic resonance imaging (MRI). With a goal of application of SPIONs in ultra-low field (ULF) MRI, we investigated the properties of SPIONs, and conducted imaging on a 6.5 mT MRI scanner. Specifically, we measured the NMR relaxivity and susceptibility of different SPIONs sample, both dominated by the core size of SPIONs. We also implemented susceptibility imaging using an bSSFP sequence to obtain positive contrast images of SPION phantoms, and present here a method to optimize the ULF susceptibility MRI images. |
| 4889 | Computer 121
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MULTIPLEX with water-fat imaging (WFI) capacity for body imaging |
| Yongquan Ye1, Zhongqi Zhang1, and Jian Xu1 | ||
1United Imaging, Houston, TX, United States |
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Keywords: Multi-Contrast, Body A multi-parametric method with WFI imaging capacity, i.e. MULTIPLEX-WFI, was developed and demonstrated. Routine two-point Dixon WFI images are additionally achieved, and a fat-suppression mask is extracted for use on the MULTIPLEX images to improve the overall image quality for body imaging. The cost of adding the WFI capacity to the MULTIPLEX method was negligible. The MULTIPLEX-WFI method was tested on phantom and in vivo knee and pelvis scans, showing much improved imaging quality for body imaging. |
| 4890 | Computer 122
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Deep Learning-based Flexible Echo Time Dual-Echo Water-Fat Separation |
| Yan Wu1, Zhitao Li1, Marcus Alley1, Zhifei Wen2, Zheng Zhong1, Fan Zhang3, John Pauly1, and Shreyas Vasanawala1 | ||
1Radiology, Stanford University, Stanford, CA, United States, 2Hoag Hospital, Newport Beach, CA, United States, 3Radiology, Stanford Children's Hospital, Stanford, CA, United States |
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Keywords: Fat, Fat, deep learning, dual-echo water-fat separation, flexible echo time We designed a deep learning-based dual-echo water-fat separation method with capability to support flexible echo times. A densely connected hierarchical network was employed, where input included dual-echo images and echo times, and ground truth images were produced using the projected power method. The model was trained and tested using 78 contrast enhanced image sets acquired with optimal echo times, and further validated on 15 non-contrast enhanced image sets obtained with different imaging parameter values. The proposed water-fat separation method has demonstrated high accuracy when dual-echo images were acquired with optimal or non-optimal echo times. |
| 4891 | Computer 123
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HiFNet: Hierarchical feature sharing network for multi-echo GRE denoising |
| Juhyung Park1, Chungseok Oh1, Sooyeon Ji1, Jonghyo Youn1, and Jongho Lee1 | ||
1Seoul National University, Seoul, Korea, Republic of |
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Keywords: Susceptibility, Susceptibility A new denoising network, HiFNet, for complex valued multi-echo GRE image denoising, is proposed. This network shared network features hierarchically from the first echo image to the last echo image, utilizing the redundancy in multi-echo GRE images along the echo dimension. When tested with synthetic noise denoising and real-world denoising experiments, the proposed network shows better performance than a network with no featuring or feature sharing in reverse order, demonstrating the effectiveness of the proposed feature sharing. |
| 4892 | Computer 124
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Correction of macroscopic field variation confounding R2* maps in UK Biobank: simulations and preliminary results in phantom |
| Chaoyue Wang1,2, Aaron T. Hess1, William T. Clarke1, Stuart Clare1, Diego Hernando3, Scott B. Reeder3, Karla L. Miller1, and Benjamin C. Tendler1 | ||
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University Of Oxford, Oxford, United Kingdom, 2SJTU-Ruijin-UIH Institute for Medical Imaging Technology, Shanghai, China, 3Departments of Radiology, University of Wisconsin, Madison, WI, United States |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties Our results suggest that R2* maps in UK Biobank are confounded by the macroscopic field variation which leads to spurious associations driven by field variations due to the air/tissue interfaces. This effect can be modeled as a signal modulation which can be removed through a voxel-wise correction. |
| 4893 | Computer 125
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Comparing Diagnostic Performance and Quality of NeuroMix (NM) to Routine Brain MRI Sequences |
| Eugene Milshteyn1, Harry Griffin2, Yi Shuen Chang2, Tim Sprenger3,4, Stefan Skare4,5, Christopher J. Maclellan2, and Salil Soman2 | ||
1GE Healthcare, Boston, MA, United States, 2Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 3GE Healthcare, Stockholm, Sweden, 4Karolinska Institutet, Stockholm, Sweden, 5Karolinska University Hospital, Stockholm, Sweden |
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Keywords: Multi-Contrast, Brain The focus of this study is to assess the diagnostic performance of NeuroMix, a single push-button, novel, fast multi-contrast MRI sequence, to that of routine brain scans that typically consist of multiple sequences. NeuroMix has the ability to provide several different contrasts in about 3.5 minutes with only one prescription and prescan. While the sequence has initially shown to be fast and motion-robust, more evaluation is needed across the various contrasts compared to gold standard, optimized sequences routinely used in the clinic. Here we present initial qualitative and quantitative comparisons between NeuroMix and routine scans across a variety of patients. |
| 4894 | Computer 126
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Characterizing the Temperature Dependence of T2 in Phantoms using an Ethylene Glycol Reference |
| Adrienne G. Siu1, Boyan Ivanov1, Alex K. Smith1, Matthew D. Robson1, and Roberto Salvati1 | ||
1Perspectum, Oxford, United Kingdom |
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Keywords: Relaxometry, Phantoms, Temperature Phantom vials of varying T2 were calibrated as a function of temperature, where the temperature was measured via multi-echo gradient echo imaging of ethylene glycol in a phantom vial. The temperature calibrations were used to adjust T2 to a reference temperature, achieving T2 deviations to within [-3.2, 2.0] ms [-3.1%, 2.9%] on Siemens 3T (16.7ºC – 25.1ºC) and [-3.5, 1.4] ms [-3.4%, 0.8%] on GE 1.5T (16.5ºC – 23.7ºC). This demonstrates that corrections for T2 due to temperature can be performed while measuring temperature from gradient-echo imaging of ethylene glycol. |
| 4895 | Computer 127
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Quantitative MR T1 Value of Arterial Plaque using 3D Black-blood MP2RAGE：A Feasibility Study |
| Qizeng Ruan1, Zehe He1, Zeping Liu2, Yuhui Nie2, Liping Liao1, Qingchun Li1, Mingxia Tan1, Lanbin Huang1, Guoxi Xie2, YuanLi Wang1, and Minglu Zhou1 | ||
1The First People’s Hospital of Qinzhou, Qinzhou, China, 2Guangzhou Medical University, Guangzhou, China |
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Keywords: Relaxometry, Cardiovascular, T1 mapping Carotid plaque is an important cause of stroke. The T1 value of the plaque could provide potential information for the diagnosis. In this work, we compared the performance of T1 mapping of BB-MP2RAGE and conventional MP2RAGE in carotid plaque. Experiments demonstrated BB-MP2RAGE could achieve more accurate measurement of T1 value for diagnosis of carotid plaque. |
| 4896 | Computer 128
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Monte Carlo simulations of transverse relaxation for assessing physico-chemical properties of novel superparamagnetic iron oxide particles |
| Lauritz Klünder1, Bastian Maus1, Maria Belen Rivas Aiello2, Thomas Kirse3,4, Cristian Strassert3,4, and Cornelius Faber1 | ||
1Clinic of Radiology, University of Münster, Münster, Germany, 2Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata - CONICET, La Plata, Argentina, 3Institut für Anorganische und Analytische Chemie, University of Münster, Münster, Germany, 4CeNTech, CiMIC, SoN, University of Münster, Münster, Germany |
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Keywords: Relaxometry, Contrast Agent, Simulations Physico-chemical properties of superparamagnetic iron oxide nanoparticles (IONP) strongly affect their impact on transverse relaxation and their efficiency as MR contrast agents. Monte Carlo simulations were developed to model relaxation in silico for two novel IONPs with distinct physico-chemical properties. The IONPs comprised an identical magnetite core but differed in preparation strategy, defining their coating and size. Simulations were compared to in vitro relaxometry measurements and reproduced experimentally measured relaxation times. Using lognormally distributed particle radii in the simulations was required to obtain correct R2* values. Together, simulations and measurements unveiled additional particle aggregation in the MR samples. |
| 4897 | Computer 129
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In Vivo Single Voxel Relaxation-Diffusion Correlation Spectra Revealed the Microstructure of Human Brain |
| Lixian Wang1,2, Tomohisa Okada3, Takashi Hanakawa1,3, Baogui Zhang2,4, Huilou Liang2, Jing An5, Rong Xue2,4,6, and Fangrong Zong2,7 | ||
1Department of Integrated Neuroanatomy and Neuroimaging, Kyoto University, Kyoto, Japan, 2Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 3Human Brain Research Center, Kyoto University, Kyoto, Japan, 4University of Chinese Academy of Sciences, Beijing, China, 5Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 6Beijing Institute for Brain Disorders, Beijing, China, 7School of Artificial Intelligence, Beijing University of Posts and Telecommunications, Beijing, China |
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Keywords: Multi-Contrast, Diffusion/other diffusion imaging techniques Multidimensional MRI resolves the correlations between physical parameters and relaxation properties and has become an increasingly important protocol in biomedical engineering. It has sub-voxel resolution but most research still uses multi-voxel ROIs. In this study, we obtained the single voxel T1-D Relaxation-Diffusion correlation spectra from in vivo human brain tissue boundaries. The significant variance in these spectra might help to identify tissue microstructure at the sub-voxel resolution. Our research disclosed the feasibility of applying multidimensional MRI techniques to detect and segment the human brain. |
| 4898 | Computer 130
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Repeatability of R1, R2* and fat fraction in Human Lumbar Vertebrae using a simultaneous multi-relaxation-time Imaging (TXI) method |
| Jie Yang1, Hao Feng1, Meining Chen2, Xu Yan2, Jianqi Li3, Yinqiao Yi3, Haodong Zhong3, and Jianquan Zhong1 | ||
1Department of Radiology, Zigong First People's Hospital, Zigong, China, 2MR Scientific Marketing, Siemens Healthineers, Shanghai, China, 3Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China |
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Keywords: Multi-Contrast, Multi-Contrast The quantitative MRI mapping techniques showed great potential in evaluating intervertebral disc degeneration (IVD) and diagnosing lower back pain. The repeatability of the quantitative methods is very important for clinical evaluation. A simultaneous multi-relaxation-time mapping (TXI) method was evaluated here, which can quantify the bone marrow fat fraction (BMFF), R2* and R1 value by a single scan and fast speed. The quantitative parameters of TXI showed high repeatability with high consistency and low CoVs, and could be applied in future clinical applications of IVD degeneration disease. |
| 4899 | Computer 131
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Analysis of spin-lock techniques for the non-invasive detection of neuronal currents with magnetic resonance |
| Milena Capiglioni1, Federico Turco1, Claus Kiefer1, and Roland Wiest1 | ||
1Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Switzerland |
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Keywords: Electromagnetic Tissue Properties, Simulations, Spin-lock, Neuronal Current Imaging Different SL techniques have been proposed to generate images based with a contrast based on neuronal activity. We analyzed the contrast of different SL techniques for the detection of oscillatory magnetic fields and their dependence with the duration of the SL and the initial phase of the target field. |
| 4900 | Computer 132
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Optimisation of T1 measurement sensitivity for Oxygen-Enhanced MRI assessment of hypoxia in patients with head and neck cancers |
| Maira Tariq1,2, Alison Macdonald2, Mathew R Orton1,2, Michael J Dubec3, David J Collins1,2, Jessica M Winfield1,2, and James P B O’Connor1,3,4 | ||
1Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom, 2MRI Unit, The Royal Marsden NHS Foundation Trust, London, United Kingdom, 3Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom, 4Radiology, The Christie NHS Foundation Trust, Manchester, United Kingdom |
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Keywords: Relaxometry, Quantitative Imaging, Oxygen-Enhanced MRI Hypoxia is an important prognostic factor for head and neck cancers (HNC). Oxygen-Enhanced MRI (OE-MRI) can map hypoxia, by quantifying change in longitudinal relaxation time, T1, but the technique suffers from low signal-to-noise ratio (SNR), which reduces the sensitivity of hypoxia detection. We optimised standard T1 mapping methods on a 1.5T scanner, to select an accurate, precise, and high SNR sequence, derived in a phantom and in healthy volunteers. 3D Variable Flip Angle spoiled gradient-echo acquisition with view-sharing, flip angles 2o and 8-10o and with B1 correction applied provided suitable protocol for clinical application. |
| 4901 | Computer 133
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FLAIR3Phase: a new synthetic MRI contrast for paramagnetic rim lesions detection in multiple sclerosis |
| Colin Vanden Bulcke1,2, Nicolas Delinte2, and Benoît Macq2 | ||
1Institute of Neurosciences, Université Catholique de Louvain, Brussels, Belgium, 2Institute for Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, Louvain-la-Neuve, Belgium |
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Keywords: Multi-Contrast, Multiple Sclerosis, Paramagnetic Rim Lesions Chronic active multiple sclerosis (MS) lesions are visible on susceptibility-based MRI as paramagnetic rim lesions (PRL); these lesions are characterized by severe tissue damage and strongly correlate with disease severity. PRL assessment is usually performed manually on unwrapped-filtered phase images. However, PRL assessment is associated with high intra/inter-rater variability due to the poor visibility of PRL and to the lack of standardized imaging protocols/guidelines for their detection. Here, we propose a new synthetic contrast called FLAIR3Phase to augment PRL assessment workflow and to reduce rater variability. |
| 4902 | Computer 134
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Brain R2 dependence on field strength |
| Yicun Wang1, Peter van Gelderen1, Jacco A de Zwart1, and Jeff H Duyn1 | ||
1AMRI, LFMI, NINDS, NIH, Bethesda, MD, United States |
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Keywords: Relaxometry, Brain Gradient Echo Sampling of Spin Echo signal was used to obtain R2 maps in nine adults at 3 T and 7 T. These were analyzed using anatomically defined ROIs, across most of the brain. Comparison between the two field strengths shows in most brain regions the R2 increases by about a factor of 1.62, with the notable exception of regions high in iron. Linear fits of R2 versus estimated iron concentration yielded 50.6 and 132 1/s/(mg/g) for 3 T and 7 T respectively, in line with prior reports at lower fields for the field dependence of iron related relaxation. |
| 4903 | Computer 135
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Whole Brain R2 Maps at 7T Highlight Iron-Rich Cortical Gray and Sub-cortical White Matter |
| Yicun Wang1, Peter van Gelderen1, Jacco de Zwart1, and Jeff H. Duyn1 | ||
1AMRI, LFMI, NINDS, NIH, Bethesda, MD, United States |
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Keywords: Relaxometry, Relaxometry, T2 mapping; Iron Gradient Echo Sampling of Spin Echo signal was used to obtain whole-brain R2 maps from 8 young and 1 senior healthy volunteers at 7T. Cortical surface reconstruction showed increased R2 in areas of high iron content as known from histology. Furthermore, high R2 in sensory-motor and visual cortices was accompanied by low R2 in underlying white matter. Highest R2 in subcortical white matter was found in frontal and temporal lobes. The low sensitivity of R2 to fiber orientation and venous vasculature may render it more suitable than R2* and $$$\chi$$$ for iron quantification, especially near the brain surface. |
| 4904 | Computer 136
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B1 and B0 insensitive R1σ preparation pulses can reduce sensitivity to R1σ dispersion |
| Kevin D Harkins1,2,3, Jason Ostenson1,2, Fatemeh Adelnia1,2, Feng Wang1,2, Zhongliang Zu1,2, and John C Gore1,2,3 | ||
1Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 2Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States |
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Keywords: Relaxometry, Simulations R1σ dispersion imaging can be used to uncover specific relaxation mechanisms in soft tissues, but is sensitive to B0 and B1 inhomogeneity. Several varieties of R1σ preparation pulses have been developed to reduce sensitivity to B0 and B1, typically by introducing a spin echo or double spin echo as part of the preparation pulse. This simulation study shows that such pulses can actually reduce the sensitivity to R1σ dispersion. |
| 4905 | Computer 137
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Free-breathing T1ρ Quantification in the Pancreas |
| Hannah J. S. Ehler1, Sharon Clarke2,3, Geoff Williams4,5, and James Rioux1,2,3 | ||
1Department of Physics & Atmpspheric Science, Dalhousie University, Halifax, NS, Canada, 2Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada, 3BIOTIC, Nova Scotia Health, Halifax, NS, Canada, 4Department of Digestive Care & Endoscopy, Dalhousie University, Halifax, NS, Canada, 5Nova Scotia Health, Halifax, NS, Canada |
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Keywords: Relaxometry, Pancreas, T1rho T1ρ quantification in the pancreas is largely unexplored due to the difficulty of compensating for breathing motion. In this study we demonstrate a free-breathing T1ρ technique for use in the abdomen which is able to quantify T1ρ in the pancreas without respiratory gating, through the use of golden-angle radial sampling. The technique was validated in phantoms and tested in three healthy volunteers. T1ρ values in the liver and spleen agreed with recent literature, while differences in T1ρ values in the pancreas may be related to the use of free breathing instead of respiratory gating. |
| 4906 | Computer 138
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Sampling Time Considerations for T1 map acquisition on the 64mT Hyperfine Swoop system: A Phantom Evaluation Study |
| Vivian S. Nguyen1,2, Sudarshan Ragunathan3, Timothy J. Carroll4, Adil Javed5, Marcella K. Vaicik1, John G. Georgiadis1, and Keigo Kawaji1,2 | ||
1Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 2Medicine - Cardiology, University of Chicago Medical Center, Chicago, IL, United States, 3Hyperfine Inc., Guilford, CT, United States, 4Radiology, University of Chicago Medical Center, Chicago, IL, United States, 5Neurology, University of Chicago Medical Center, Chicago, IL, United States |
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Keywords: Relaxometry, Low-Field MRI T1 maps provide quantitative relaxometric measures of tissue responses that may carry correlative indices of specific disease indications. On the recently commercialized 64mT system (Hyperfine Inc.), little has been reported regarding both clinical T1 relaxometric normal values in presence of Gadolinium-based contrast and relevant acquisition schemes with Gd contrast enhancement. In this study, we examine an array of Gadolinium-doped vials that represent 10-5000 fold dilution in the vasculature using an Inversion-Recovery FSE acquisition to gain key insights on: a) anticipated normal values in presence of Gd, b) conventional fitting algorithm performance, and c) potential inferences on inversion timing selection. |
| 4987
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Computer 41
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Dynamic 3D Stack-of-Radial Multi-Baseline PRF MR Thermometry using Compressed Sensing Reconstruction and Image-Based Navigation |
| Qing Dai1,2, Shu-Fu Shih1,2, Jiaqi Zhou3, Le Zhang1, and Holden H Wu1,2 | ||
1Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States, 3Department of Engineering Physics, Tsinghua University, Beijing, China |
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Keywords: Thermometry, Motion Correction, Multi-baseline Thermometry Multi-baseline proton resonance frequency-shift (PRF) MR thermometry can reduce motion-induced temperature errors in moving organs during MR-guided thermal therapy. However, previous methods had to compromise the spatial coverage to increase the temporal resolution for resolving motion. This work developed a dynamic 3D stack-of-radial MRI method using compressed sensing reconstruction and image-based navigation to enable motion-resolved multi-baseline PRF thermometry with 1.4-sec true temporal resolution. The proposed method achieved stable thermometry with volumetric coverage in free-breathing liver MRI without heating. |
| 4988 | Computer 42
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A dual-flip angle bSSFP imaging method for proton resonance frequency-based thermometry |
| Seohee So1, HyunWook Park2, and Hyunseok Seo1 | ||
1Korea Institute of Science and Technology, Seoul, Korea, Republic of, 2Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of |
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Keywords: Thermometry, Thermometry Proton resonance frequency thermometry estimates temperature change by detecting the frequency change which is proportional to that of the temperature. In this study, we propose a dual- flip angle bSSFP thermometry method that generates a high intensity signal and linear phase to the frequency shift. Two steady states of the proposed method have phase dependency on the off-resonance frequency and the phase difference between the steady states has a linear relation with the off-resonance frequency. The linear phase relation makes it possible to measure temperature change. And the acquired high intensity signal benefits temperature monitoring and guidance for thermal therapy. |
| 4989 | Computer 43
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Applicability of Magnetic Resonance Fingerprinting for Proton Resonance Frequency Shift based Temperature Monitoring of Microwave Ablation |
| Moritz Gutt1, Josef Joaquin Löning Caballero2, Dominik Horstmann2, Frank Wacker2, Bennet Hensen2, and Marcel Gutberlet2 | ||
1Computational Health Informatics, Leibniz University Hannover, Hannover, Germany, 2Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany |
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Keywords: Thermometry, MR Fingerprinting MRI offers the unique ability of measuring the temperature inside of the patient during minimally invasive tumor ablation. In this proof-of-concept approach MR Fingerprinting was used in order to get an accurate thermometry with potential for real-time application. The method was validated by performing a microwave ablation in a bioprotein phantom. The temperature accuracy was 1.54 °C ± 0.85 °C and the dice score between the calculated and the ground truth denaturation zone was 90.02 %. The mean standard deviation of the non-heated area was 0.19 °C. |
| 4990 | Computer 44
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MR Thermometry by Quadratic Phase MR Fingerprinting |
| Sarah J Garrow1, John Peters1, Abby Grillo1, Rasim Boyacioglu2, Kathryn E Keenan3, Mark A Griswold2, and William A Grissom1 | ||
1Vanderbilt University, Nashville, TN, United States, 2Case Western Reserve University, Cleveland, OH, United States, 3National Institute of Standards and Technology, Boulder, CO, United States |
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Keywords: Thermometry, MR-Guided Interventions PRF-shift thermometry is the current standard for MR-based temperature monitoring in interventional procedures and works by converting gradient-recalled image phase changes to temperature changes. However, the long TE required for phase contrast increases sensitivity to artifacts from motion. We propose to address this using quadratic phase MR fingerprinting (qRF-MRF) which is robust to spurious artifacts. We implemented a qRF-MRF sequence that sweeps continuously across resonance frequencies and is highly sensitive to heating-induced resonance frequency changes. The sequence was used to monitor laser heating in a phantom, with comparison to GRE thermometry. |
| 4991 | Computer 45
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Sparse regression-based delineation of air-motion artifacts for real-time correction of PRFS thermometry |
| Sven Nouwens1, Maarten Paulides2,3, and Maurice Heemels1 | ||
1Mechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 2Electrical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 3Radiotherapy, Erasmus MC, Rotterdam, Netherlands |
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Keywords: Sparse & Low-Rank Models, Thermometry, susceptiblity aritfact correction Proton resonance frequency shift-based MR thermometry is widely used to non-invasively monitor thermal therapies in vivo. However, further clinical integration in deep hyperthermia is hampered by intestinal air-motion induced susceptibility artifacts. We developed a sparse regression approach to delineate susceptibility artifact sources. The resulting mask is then used to correct the artifact using existing methods from quantative susceptibility mapping. We verified our approach by a heated phantom experiment equipped with a moveable air volume and temperature probes. Here, we found a reduction in the mean absolute error from 1.6 degrees Celsius to 0.4 degrees Celsius, near the air-motion artifact. |
| 4992 | Computer 46
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Compensation for Sporadic Motion in MR Thermometry Though a Hybrid Augmented Multi-Baseline and Near-Referenceless Approach |
| Arthur Akbulatov1, Suzanne M Wong1,2, Craig A Macsemchuk1,2, Andrew Headrick1, James M Drake1,2, and Adam C Waspe1,3 | ||
1Posluns Centre for Image Guided Innovation & Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, Canada, 2Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada, 3Department of Medical Imaging, University of Toronto, Toronto, ON, Canada |
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Keywords: Motion Correction, Motion Correction Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) treatments are limited by motion artifacts introduced into MR thermometry calculations by large sporadic motions. A hybrid principal component analysis and projection onto dipole fields (PCA-PDF) motion compensation algorithm was expanded upon to include predicted motion using image augmentation techniques. When tested on MR images from a gelatin phantom being translated in the coronal plane, the improved PCA-PDF algorithm yielded a temperature standard deviation of 0.4 ± 0.1 °C, which is a 3.7 ± 0.1 °C reduction from an unmodified PCA-PDF approach, indicating that thermometry artifacts induced by motion were significantly reduced. |
| 4993 | Computer 47
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Validation of an MR Thermometry Motion Compensation Algorithm for Periodic Motion During MR guided High Intensity Focused Ultrasound (MRgHIFU) |
| Suzanne M Wong1,2, Craig A Macsemchuk1,2, Andrew Headrick1, Phoebe Luo1, Arthur Akbulatov1, James M Drake1,2, and Adam C Waspe1,3 | ||
1Posluns Centre for Image Guided Innovation & Therapeutic Interventions, Hospital for Sick Children, Toronto, ON, Canada, 2Department of Biomedical Engineering, University of Toronto, Toronto, ON, Canada, 3Department of Medical Imaging, University of Toronto, Toronto, ON, Canada |
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Keywords: Motion Correction, Thermometry Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) can noninvasively administer controlled hyperthermia as an adjuvant cancer therapy. For clinical translation, one of the main challenges is the sensitivity of MR thermometry to motion artifacts. This work aims to validate a real-time hybrid principal component analysis and projection onto dipole fields (PCA-PDF) motion compensation algorithm on a clinical MRgHIFU system during reproducible motion profiles. The real-time PCA-PDF algorithm maintained a temperature standard deviation of < 1°C in a phantom while the periodic motion was induced on a phantom using an MR-compatible robot. |
| 4994 | Computer 48
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Deep Learning based drift field correction for MR Thermometry in the upper leg at 7T |
| E.F. Meliadò1,2,3, M.W.I. Kikken1, B.R. Steensma1,2, C.A.T van den Berg2,4, and A.J.E. Raaijmakers1,2,5 | ||
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Computational Imaging Group for MR diagnostics & therapy, Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, 3Tesla Dynamic Coils BV, Zaltbommel, Netherlands, 4Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 5Biomedical Image Analysis, Dept. Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands |
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Keywords: Safety, Thermometry PRFS-based MR Thermometry (MRT) bears strong potential for RF safety assessment. However, PRFS-MRT is impaired by external sources of frequency shift. It is hypothesized that deep learning will be able to separate the PRFS signal from these other sources of frequency shift. This study has tested this concept on drift field correction for MRT in the human thigh at 7T. A convolutional neural network is trained using synthetic phase difference images based on measured drift fields and simulated temperature distributions. Results show that the proposed deep-learning approach is able to correctly predict both simulated and measured temperature rise distributions. |
| 4995 | Computer 49
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Evaluating Various Phase Drift Correction Methods in PRFS-based Thermometry in the Pelvic Region of Free-Breathing Volunteers |
| Othmar Belker1,2, Bennet Hensen1,2, Frank Wacker1,2, and Marcel Gutberlet1,2 | ||
1Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany, 2STIMULATE-Solution Centre for Image Guided Local Therapies, Magdeburg, Germany |
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Keywords: System Imperfections: Measurement & Correction, Thermometry, Proton Resonance Frequency Shift, Phase Drift Proton Resonance Frequency Shift Thermometry relies on a homogeneous B0-field as the B0-field significantly influences the resonance frequency. A multitude of phase drift correction methods have been proposed. The temperature accuracy and computing time of reference-less phase estimation, prospective, and fat-based phase correction have been evaluated in a manually segmented dorsal muscle ROI in the pelvic region of free-breathing volunteers. The evaluated phase drift correction methods correct phase drift comparably regarding temperature accuracy. Fat-based and prospective phase correction are almost ten times faster than reference-less phase estimation but require a reliable baseline acquisition. |
| 4996 | Computer 50
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Optimization of EPI based PRF thermometry at 0.5 T |
| Chad T Harris1, Curtis N Wiens1, Diego F Martinez2, Andrew T Curtis1, and Blaine A Chronik2 | ||
1Research and Development, Synaptive Medical, Toronto, ON, Canada, 2The xMR Labs, Department of Physics and Astronomy, Western University, London, ON, Canada |
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Keywords: Data Acquisition, Thermometry Echo planar imaging (EPI) is well-suited for temperature mapping in the mid-field (0.5T) thanks to longer T2* values that can be leveraged without prohibitively slow update rates. In this work, we optimize EPI based PRF thermometry acquisitions for mid-field MRI. Digital simulations and in-vivo temperature stabilities were computed over echo times ranging from 50ms – 100ms. The optimal mean temperature uncertainty over the entire acquisition volume was measured to be approximately 1⁰C demonstrating that EPI based thermometry provides clinically viable sensitivity at 0.5T with sufficient image resolution and extremely fast update rates (1.3-2 s). |
| 4997 | Computer 51
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Monitoring Temperature using Gradient Echo Imaging at 0.5T |
| Diego F Martinez1, Chad T. Harris2, Curtis N. Wiens2, Will B. Handler1, and Blaine A. Chronik1,3 | ||
1The xMR Labs, Physics and Astronomy, Western University, London, ON, Canada, 2Research and Development, Synaptive Medical, Toronto, ON, Canada, 3Medical BioPhysics, Western University, London, ON, Canada |
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Keywords: Thermometry, Phantoms Gradient Echo Proton Resonant Frequency (GRE-PRF) based thermometry, a standard approach to temperature mapping, was assessed at 0.5T. Experiments were performed using a 3 slice GRE acquisition at a resolution of 2x2x5mm and an update rate of 7.7s. Phantom and in-vivo measurements of the temperature stability yielded uncertainties of 0.78°C and 1.48°C respectively. Furthermore, a cooling experiment with the phantom showed excellent agreement to temperature changes simultaneously measured with a temperature probe. All results suggest that GRE-PRF thermometry is feasible at 0.5T. |
| 4998 | Computer 52
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Low field cardiac MR thermometry: feasibility at 0.55T |
| Ronald Mooiweer1,2, Charlotte Rogers1, Radhouene Neji1,2, Reza Razavi1, and Sébastien Roujol1 | ||
1School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Camberley, United Kingdom |
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Keywords: Myocardium, Thermometry Low field strength MRI scanners are appealing for MR guided interventions because of their lower associated costs and increased compatibility with interventional devices. Cardiac PRFS thermometry shows promise for real-time guidance of ablation therapy of cardiac arrhythmias. In this study, initial characterization of cardiac PRFS thermometry at 0.55T was performed in 5 healthy volunteers by measuring the stability over time. The stability of thermometry was 1.6±0.8 °C in the myocardium, confirming feasibility at this field strength. |
| 4999 | Computer 53
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PRF thermometry at 0.55T using multi-contrast segmented EPI approach |
| Waqas Majeed1, Henrik Odéen2, Dennis L. Parker2, Florian Maier3, Jianing Pang1, and Axel J. Krafft3 | ||
1Siemens Medical Solutions USA Inc., Malvern, PA, United States, 2Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 3Siemens Healthcare GmbH, Erlangen, Germany |
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Keywords: Thermometry, Multi-Contrast, Prostate, Brain MR thermometry based on the proton resonance frequency (PRF) shift is a widely used tool to monitor changes in tissue temperature in response to MR-guided thermal interventions. However, MR temperature mapping at low field (< 1T) is challenging because of reduced signal to noise ratio (SNR) and intrinsically low temperature-sensitivity of the PRF shift. In this work, we present a multi-contrast segmented EPI sequence for PRF thermometry at low field. The proposed sequence provides high sampling efficiency and improves temperature quantification via echo combination. The performance of the sequence was tested in healthy volunteer measurements in the absence of heating. |
| 5000 | Computer 54
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Susceptibility artifacts during MR-guided laser interstitial thermal therapy: characterization and temperature-based control solutions |
| De Landro Martina1, Céline Giraudeau2, Juan Verde2, Khalid Ambarki3, Sanzhar Korganbayev1, Henrik Odeen4, Benoît Gallix2, and Paola Saccomandi1 | ||
1Politecnico di Milano, Milan, Italy, 2IHU Strasbourg, Institute of image-guided surgery, Strasbourg, France, 3Siemens Healthcare SAS, Saint Denis, France, 4University of Utah, Salt Lake City, UT, United States |
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Keywords: Interventional Devices, MR-Guided Interventions The use of Magnetic Resonance Thermometry (MRT) has been proposed to intraoperatively guide laser interstitial thermal therapy (LITT) thanks to its ability to provide multidimensional temperature measurements. PRF-based MRT thermometry holds significant benefits, but it is still limited by susceptibility artifacts that significantly affect the accuracy of measured temperature maps. These artifacts lead to a negative temperature distribution with a double-lobe shape around the laser applicator. In this work, artifacts appearing in MRT images during LITT and linked to magnetic field distortion related to susceptibility variations are characterized in ex-vivo livers. We further propose an approach to avoid their appearance. |
| 5001 | Computer 55
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Real-time automatic temperature regulation during in-vivo MRI-guided Laser-induced Thermo-Therapy (MR-LITT) |
| Manon Desclides1,2, Valéry Ozenne1, Pierre Bour2, Thibault Faller2, Guillaume Machinet3, Christophe Pierre3, Stéphane Chemouny2, and Bruno Quesson1 | ||
1University of Bordeaux, CNRS, CRMSB, UMR 5536, IHU Liryc, Bordeaux, France, Metropolitan, 2Certis Therapeutics, Pessac, France, 3ALPhANOV, Talence, France |
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Keywords: Interventional Devices, MR-Guided Interventions The presented method allows to automatically adjust laser power relying on real-time rapid volumetric MR-thermometry using the proton resonance frequency (PRF) shift technique. The laser output power is regulated every second to force temperature to follow a predefined temperature-time profile using a PID controller, taking MR-temperature data as input. The proposed temperature regulation algorithm is successfully validated in vivo in the skeletal muscle of a pig. |
| 5002 | Computer 56
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Minimally invasive measurement of arterial and brain temperature in the mouse |
| Lisa M Gazdzinski1, Luke Chung1,2, Shoshana Spring1, Owen Botelho1, Bojana Stefanovic2,3, Brian J Nieman1,2,4, Chinthaka C Heyn3,5, and John G Sled1,2 | ||
1Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 4Ontario Institute for Cancer Research, Toronto, ON, Canada, 5Medical Imaging, University of Toronto, Toronto, ON, Canada |
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Keywords: Thermometry, Metabolism, lanthanide, mice, brain Brain temperature is an important physiological parameter that both reflects and modulates brain activity, but current in vivo thermometry methods are invasive and/or impractical for small animals. We present a minimally invasive method for measuring blood and brain temperature in mice using Tm-DOTMA and characterize the relationship between brain and blood temperature under isoflurane anesthesia. Brain temperature was strongly correlated and approximately equal to the temperature of the inflowing arterial blood, possibly reflecting the vasodilatory and metabolic suppressive effects of isoflurane. Application of this method with alternative anesthesia approaches would provide insight into brain temperature regulation in health and disease. |
| 5003 | Computer 57
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Feasibility of fast single-phase volumetric cardiac MR-thermometry |
| Charlotte Rogers1, Ronald Mooiweer1,2, Grzegorz Kowalik1, Radhouene Neji1,2, Reza Razavi1, Rene Botnar1,3,4, and Sebastien Roujol1 | ||
1School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Camberley, United Kingdom, 3School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 4Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile |
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Keywords: Myocardium, Thermometry A novel fast simultaneous multi-slice black blood cardiac thermometry sequence is presented which allows multiple slices to be acquired in the same cardiac phase. A double inversion recovery pre-pulse is introduced to allow blood suppression and to optimise the pre-pulse strategy and therefore reduce acquisition time. Simultaneous multi-slice (SMS) imaging is integrated to further reduce the acquisition time of the multiple slices. Thermometry results obtained with this technique show an average temperature stability of 1.0±0.4°C in healthy subjects. |
| 5004 | Computer 58
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Thermometry of frozen tissue during cryoablation at 1.5T with a novel 3D spiral staircase UTE sequence (SSCUTE) – A feasibility study |
| Guruprasad Krishnamoorthy1,2, Jacinta Browne2, Aiming Lu2, David A. Woodrum2, and James G. Pipe2 | ||
1MR R&D, Philips Healthcare, Rochester, MN, United States, 2Department of Radiology, Mayo Clinic College of Medicine and Science, Rochester, MN, United States |
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Keywords: New Trajectories & Spatial Encoding Methods, Thermometry This study assessed the feasibility of thermometry of frozen tissue during MRI-guided cryoablation at 1.5T using a novel 3D spiral staircase UTE sequence (SSCUTE). MRI data using the SSCUTE sequence were continuously acquired along with temperature measurements during several freeze-thaw cycles in ex-vivo porcine specimens. A calibration curve was obtained using temperature measurements and corresponding MRI data. MRI-estimated temperature maps were generated with high accuracy using the calibration curve on a validation dataset. Our work demonstrated the feasibility of thermometry of frozen tissue using SSCUTE sequence at 1.5T, which could be an essential step in clinical adoption of this technique. |
| 5005 | Computer 59
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A New-found Approach to Temperature Monitoring Utilizing a Magnetic Field Map |
| Sangwoo Kim1 and Sukhoon Oh2 | ||
1Daewon University College, Jecheon-si, Korea, Republic of, 2Korea Basic Science Institution, Ochang-eub, Korea, Republic of |
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Keywords: Safety, Thermometry We showed a new approach of MR temperature mapping without the oil-based phase reference of the conventional proton resonance frequency shift method (cPRFS), named as delta field-corrected temperature mapping (DFCTM). The performance of the DFCTM was compared with measurements using fiber optic thermal sensor and the cPRFS at the human-tissue mimicking agar-gel phantom. The sensor–measured temperature range was 6.05 ℃, while the DFCTM exhibited about 5.93 ℃. It exhibited a difference of -0.12 ℃ and the RMSE of the DFCTM was 0.16 ℃ for the entire experiments, which means that it could realize a temperature monitoring without oil phantoms. |
| 5006 | Computer 60
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Accelerated MRI thermometry guidance for transurethral ultrasound ablation of the prostate using locally low rank reconstruction |
| Ben YC Leung1, Robert M. Staruch1, and Mark Chiew2,3 | ||
1Profound Medical, Mississauga, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada |
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Keywords: Thermometry, Interventional Devices, TULSA MRI-guided transurethral ultrasound ablation of the prostate (TULSA) is controlled based on dynamic proton resonance frequency shift MR temperature imaging. Given the localized, but spatio-temporally coherent heating pattern, locally low rank (LLR) reconstruction could facilitate accelerated thermometry. Images acquired during TULSA in a phantom were retrospectively under-sampled by acceleration factors of R=3,4,6 by randomly sub-sampling EPI segments, and reconstructed using LLR constraints with non-overlapping 4D patches and cycle-spinning patch shifts. LLR reconstruction demonstrated lower variance than GRAPPA reconstructions in unheated regions, but increasing measurement bias at R≥4. In vivo investigation of LLR reconstruction of MR thermometry for TULSA is warranted. |
| 5007 | Computer 61
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Optimized diffusion-prepared 3D-MRF for rapid high-resolution whole-brain T1, T2, proton density, ADC and FA mapping |
| Xiaozhi Cao1,2, Congyu Liao1,2, Zihan Zhou3, Zheng Zhong1, Zhitao Li1, Erpeng Dai1, Siddharth Srinivasan Iyer1,4, Airel Hannum1,5, Mahmut Yurt1,2, Sophie Schauman1,2, Quan Chen1, Nan Wang1, Yifan Yan3, Hongjian He3, Stefan Skare6, Jianhui Zhong7, Adam Kerr2, and Kawin Setsompop1,2 | ||
1Department of Radiology, Stanford university, Stanford, CA, United States, 2Department of Electrical Engineering, Stanford university, Stanford, CA, United States, 3Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China, 4Department of Electrical Engineering and Computer Science, MIT, Cambridge, MA, United States, 5Department of Bioengineering, Stanford university, Stanford, CA, United States, 6Department of Clinical Neuroscience, Karolinska Institute, Solna, Sweden, 7Department of Imaging Sciences, University of Rochester, Rochester, NY, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Brain In this work, a diffusion preparation was implemented into the 3D spiral-projection MRF sequence to introduce additional diffusion weighting and enables whole-brain T1, T2, PD, ADC and FA mapping with 1-mm isotropic resolution within 10min. To maximize the diffusion signal and image-encoding efficiency, a diffusion-preparation without an amplitude stabilizer is employed, where robustness against phase variations is achieved using a combination of M1-compensated encoding, cardiac-gating, and an eddy-current compensating pre-pulse gradient. The MRF acquisition scheme and subspace reconstruction were also modified to enable effective data sharing across diffusion directions, which increase acceleration capability and improve mapping quality. |
| 5008 | Computer 62
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The link between superficial and deep white matter fibers |
| Maxime Chamberland1, Dmitri Shastin2, Derek K. Jones2, David G. Norris1, and Kurt G. Schilling3,4 | ||
1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands, 2Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom, 3Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 4Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States |
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Keywords: Tractography & Fibre Modelling, White Matter, U-fibers, Diffusion MRI, Tractometry, Visualization Here we visualized how superficial association fiber (SAF) systems relate to deep white matter bundles. We found that various shape features can be reliably extracted from those systems. The combination of superficial white matter tractography with traditional deep white matter bundles opens possibilities to study bundle-specific SAF in health and disease. |
| 5009 | Computer 63
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Multi-Scanner Reproducibility of IVIM Quantification in the Liver using Pseudo-Diffusion and Physical IVIM Signal Models |
| Gregory Simchick1,2, Timothy J Allen2, and Diego Hernando1,2 | ||
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin-Madison, Madison, WI, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Data Acquisition Intravoxel incoherent motion (IVIM) quantification in the liver suffers from instability associated with separating multiple decaying signal components sampled along a single dimension (b-value). In this work, monopolar and 2D (b-value and first-order motion moment (M1)) noise-optimized IVIM-DWI acquisitions were acquired on three MR scanners with different MR gradient hardware. From each acquisition, IVIM estimates were obtained using pseudo-diffusion and physical (M1 dependent) IVIM signal models. Inter-scanner reproducibility and interlobar agreement were compared across acquisitions and models. 2D (b-M1) IVIM-DWI acquisitions combined with physical IVIM signal modeling improved reproducibility of IVIM quantification in comparison to monopolar acquisitions and pseudo-diffusion modeling. |
| 5010 | Computer 64
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Time-dependence in Tensor-Valued Encoding in Ex Vivo Rat Heart |
| Richard J. Foster1, Samo Lasič2,3, Henrik Lundell2, Filip Szczepankiewicz4, Leah Khazin1, Sven Plein1, Erica Dall'Armellina1, Nadira Y. Yuldasheva1, Jürgen E. Schneider1, and Irvin Teh1 | ||
1Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Copenhagen, Denmark, 3Random Walk Imaging, Lund, Sweden, 4Medical Radiation Physics, Clinical Sciences Lund, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Heart, Time dependence, Myocardium, Microstructure, q-space, QTI Tensor-valued encoding is a promising technique for improving specificity in assessing the myocardial microstructure, but can be confounded by time-dependent diffusion (TDD). Here, the influence of TDD on q-space trajectory imaging (QTI) was examined in ex vivo rat heart, using 17 diffusion encoding waveforms with different frequency content and b-tensor shapes. We report apparent over/underestimation of QTI parameters when waveforms had different sensitivity to TDD, and demonstrate a means of frequency matching that reduced the apparent bias. Acquiring QTI at higher frequencies may provide greater sensitivity to intracellular structures, complementing QTI at lower frequencies. |
| 5011 | Computer 65
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M1-optimized Liver DWI using Tetrahedral Diffusion Gradients on Conventional Gradient Systems |
| Timothy J Allen1, Srijyotsna Volety1, Greg Simchick2, and Diego Hernando1,2 | ||
1Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 2Radiology, University of Wisconsin-Madison, Madison, WI, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Motion Correction M1-optimized diffusion gradient waveforms allow for motion-robust liver DWI and ADC estimation. However, existing implementations have been limited to 3.0T scanners with high-performance gradient systems. This work introduces M1-optimized waveforms using a tetrahedral diffusion encoding to allow for high quality, motion-robust DWI on a 1.5T system with conventional gradient performance. Additionally, it addresses complications of this approach, namely increased concomitant gradients and eddy currents. Phantom experiments demonstrate a reduction in geometric distortion and bias of ADC maps generated with this approach compared to Stejskal–Tanner (monopolar) and non-tetrahedral gradient designs. Human subject imaging demonstrates increased motion-robustness. |
| 5012 | Computer 66
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A novel streamline representation to reduce redundancy in tractography |
| Ilaria Gabusi1, Matteo Battocchio1,2, Sara Bosticardo1,3, Simona Schiavi1,4, and Alessandro Daducci1 | ||
1Department of Computer Science, University of Verona, Verona, Italy, 2Department of Computer Science, University of Sherbrooke, Sherbrooke, QC, Canada, 3Department of Biomedical Engineering, University of Basel, Basel, Switzerland, 4Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy |
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Keywords: Tractography & Fibre Modelling, Tractography & Fibre Modelling Diffusion MRI tractography allows one to characterize brain connectivity in vivo, and it is common practice to reconstruct millions of streamlines and filter them a posteriori. However, redundancy among streamlines leads to collinearity in the linear operators used by existing filtering algorithms. To solve this problem, we propose a novel streamline representation which uses a combination of clustering and spatial blur to reduce redundancy. This representation is as accurate as state-of-the-art filtering methods and more robust to noise/perturbations in the input, but requires only ≈5% of the input streamlines thus decreasing both storage requirements and computational complexity. |
| 5013 | Computer 67
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Novel light-sheet scattering microscopy for voxel-wise validation of 3D-fibre orientations in murine white matter |
| Mario Corral-Bolaños1,2, Tram Nguyen1, Hans Martin Kjer1, Marco Pizzolato1,2, Casper Bo Gravesen Salinas3, Johanna Perens3, Jeppe Revall Frisvad1, Julien Colombelli4, and Tim Bjørn Dyrby1,2 | ||
1Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark, 2Danish Research Centre for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager & Hvidovre, Copenhagen, Denmark, 3Gubra, Hørsholm, Denmark, 4Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain |
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Keywords: Validation, Tractography & Fibre Modelling, 3D-Fibre orientation This work develops a novel 3D validation technique that reveals the white matter orientation with micron resolution in cleared murine brains. Light-sheet elastic scattering microscopy (LSSM) can be used to exploit the scattering signal exhibited by white matter fibres, which is dependent on their orientation. The rotation and imaging of the sample yield a scattering profile, which corresponds to that of infinitely long cylinders. Our work combines two orthogonal acquisitions to voxel-wise reconstruct 3D-fibre orientations in large brain volumes. LSSM could be the definitive validation method for diffusion MRI orientation methods. |
| 5014 | Computer 68
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Hierarchical modelling of crossing fibres in the white matter |
| Hossein Rafipoor1, Frederik Lange1, Michiel Cottaar1, and Saad Jbabdi1 | ||
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom |
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Keywords: Tractography & Fibre Modelling, White Matter, Fixel based analysis Fibre orientation distribution function (fODF) estimation is usually applied independently for each subject. This can lead to inconsistent fODF estimation across subjects complicating tract-level (i.e., fixel-based) analysis. Here we propose a hierarchical model to extract consistent tract-specific metrics across subjects that permit group comparisons and the development of more reliable biomarkers for disease and biological processes. |
| 5015 | Computer 69
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Assessing the variability of brain diffusion MRI preprocessing pipelines using a Region-of-Interest analysis |
| Jelle Veraart1, Stefan Winzeck2,3, Álvaro Planchuelo-Gómez4,5, Björn Fricke6, Evgenios N. Kornaropoulos7,8, Harri Merisaari9,10, Tomasz Pieciak5, Yukai Zou11,12, and Maxime Descoteaux13 | ||
1Center for Biomedical Imaging, Dept. Radiology, NYU Grossman School of Medicine, New York, NY, United States, 2BioMedIA Group, Department of Computing, Imperial College London, London, United Kingdom, 3Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom, 4CUBRIC, Cardiff University, Cardiff, United Kingdom, 5ETSI Telecomunicación, Universidad de Valladolid, Valladolid, Spain, 6Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 7CRMBM, Aix-Marseille University, Marseille, France, 8Diagnostic Radiology, Lund University, Lund, Sweden, 9Department of Radiology, University of Turku, Turku, Finland, 10TBMC, University of Turku, Turku, Finland, 11Medical Physics Department, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom, 12Clinical Neurosciences, Clinical and Experimental Sciences, University of Southampton, Southampton, United Kingdom, 13Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science department, Université de Sherbrooke,, Sherbrooke, QC, Canada |
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Keywords: Diffusion/other diffusion imaging techniques, Data Processing The lack of a standardized preprocessing pipeline is a significant source of variability that might lower the reproducibility of studies, especially across sites and with incomplete description of the preprocessing workflows. We evaluate the downstream impact of variability in preprocessing workflow by quantifying the reproducibility and variability of region-of-interest (ROI) analyses. While many pipelines achieve excellent reproducibility in most ROI, we observed a large variability in performance of preprocessing workflows to the extent that some pipelines are detrimental to the data quality and reproducibility. |
| 5016 | Computer 70
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Voxel-level denoising of diffusion MRI using a rank-1 decomposition |
| Siebe Leysen1,2, Stefan Sunaert2,3, Frederik Maes1,2, and Daan Christiaens1,2 | ||
1Department of Electrical Engineering, ESAT/PSI, KU Leuven, Leuven, Belgium, 2Medical Imaging Research Center, UZ Leuven, Leuven, Belgium, 3Translational MRI, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium |
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Keywords: Diffusion/other diffusion imaging techniques, Signal Representations, Denoising A voxel-wise rank-1 decomposition in spherical harmonics of the dMRI signal allows for a denoising method with minimal assumptions on signal and noise distributions. A voxel-wise denoising strategy is compared to MP-PCA on in vivo data and simulated data. The rank-1 decomposition and MP-PCA show visually similar results on the in vivo data, indicating that a voxel-level denoising approach has potential. However, results on the simulations differ. This may have various explanations; further investigation is necessary to strengthen the credibility of a rank-1 decomposition as a denoising approach. |
| 5017 | Computer 71
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Multiexponential analysis of diffusion exchange times reveals a distinct exchange process associated with metabolic activity |
| Teddy Xuke Cai1,2, Nathan Hu Williamson1, Rea Ravin1,3, and Peter Joel Basser1 | ||
1Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States, 2Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 3Celoptics, Inc., Rockville, MD, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Data Analysis, Exchange Contrary to prevailing views, recent work suggests that steady-state water exchange between the intra- and extracellular space is driven, in part, by active metabolic processes. To support these findings, we investigate whether exchange exhibits multiexponential behavior consistent with distinct exchange processes. We find a bimodal distribution of exchange times in live neural tissue, with only the faster peak being reduced upon the introduction of a sodium-potassium pump inhibitor, thus supporting the existence of active exchange. Furthermore, we describe a time-efficient method of isolating exchange and fitting multiexponential exchange times using diffusion exchange spectroscopy, paving the way for future studies. |
| 5018 | Computer 72
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Improving in vivo MR g-ratio mapping via calibration of linearly transformed MR markers from in situ to ex vivo |
| Jan Malte Oeschger1, Francisco Javier Fritz1, Mohammad Ashtarayeh2, Maria Morozova3,4, Tobias Streubel1, Henriette Rusch4, Markus Morawski4,5, Nikolaus Weiskopf5,6, and Siawoosh Mohammadi1,5 | ||
1Department of Systems Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Department of Systems Neurosciences,, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3Department of Neurophysics,, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 4Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany, 5Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 6Faculty of Physics and Earth Sciences, Felix Bloch Institute for Solid State Physics, Leipzig, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques, G-ratio In vivo MR g-ratio mapping relies on a calibrated method that relates myelin and axon MR markers to volume fractions. To estimate the calibration parameter, fixed ex vivo tissue measured with MRI and histology is used. The so-determined calibration parameter is then applied in vivo, neglecting the difference in the MR markers due to fixation. Here, we proposed a new calibration method accounting for this difference. The new calibration reduced the variability across MR g-ratios based on different myelin and axon markers, indicating that it can improve the accuracy of MR g-ratios. |
| 5019 | Computer 73
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Diffusion diffraction in disordered systems |
| Sune Jespersen1,2 and Dmitry S. Novikov3 | ||
1Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 2Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, 3Radiology, New York University School of Medicine, New York, NY, United States |
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Keywords: Microstructure, Diffusion/other diffusion imaging techniques, diffraction, disordered systems, exchange We identify a new regime for the diffusion signal in non-confining disordered systems with locally varying diffusivity. It occurs at long times and large diffusion wavevectors, reminiscent of diffusion diffraction in closed pores. Remarkably, while for free diffusion the signal is exponentially strongly dephased, scattering off heterogeneities results in a much weaker, power-law decrease of the signal, thereby offering an enhanced sensitivity to the medium’s structure. In particular, we show how correlation functions of the medium’s microstructure to arbitrary order can be measured. We compare our theoretical predictions for the second order correlation function to numerical simulations with good agreement. |
| 5020 | Computer 74
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Estimating transcytolemmal water exchange from the Kärger model using a Bayesian method in a rat model of ischemic stroke |
| Ruicheng Ba1, Yuhui Ma2, Kuiyuan Liu1, Tianshu Zheng1, Haotian Li1, Chen Li2, Xiaoli Wang2, and Dan Wu1 | ||
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hanzhou, China, 2Department of Medical Imaging, Weifang Medical University, Shandong, China |
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Keywords: Diffusion/other diffusion imaging techniques, Brain Transcytolemal water exchange can be estimated using diffusion-time-dependent diffusion kurtosis imaging acquired at long diffusion times. However, dMRI signals acquired at long diffusion times using STEAM sequences are typically noisy, and fitting of the nonlinear kurtosis model and the Kärger model accumulates fitting errors. Here, we proposed a Bayesian method for estimating transcytolemal exchange time from the Kärger model and compared accuracy and robustness with conventional least square fitting method in both simulated data and rat brain data in a model of transient middle cerebral artery occlusion. Results indicated improved fitting accuracy and robustness against noise using the Bayesian approach. |
| 5021 | Computer 75
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Micro-anisotropy and time-dependent diffusion in the mouse brain in vivo with spherical tensor encoding and the spectral principal axis system |
| Samo Lasic1, Nathalie Just1, Matthew Budde2, and Henrik Lundell1 | ||
1Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Copenhagen, Denmark, 2Department of Neurosurgery, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, , USA, WI, United States |
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Keywords: Microstructure, Diffusion/other diffusion imaging techniques, Tensor-valued encoding, time-dependent diffusion Accounting for time-dependent diffusion (TDD) in tensor-valued encoding is required for unbiased assessment of microscopic anisotropy (µA). We have previously introduced the spectral principle axis system (SPAS) to find linear tensor encoding (LTE) projections of spherical tensor encoding (STE) with maximum spread of sensitivity to TDD. This can be used to simultaneously achieve unbiased µA and TDD contrasts within a single protocol. Here we present results from in vivo experiments in a mouse brain. The two independent contrasts (µA- TDD) indicate consistent variations in different brain regions. |
| 5022 | Computer 76
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Toolkit for capillary pseudo-diffusivity Monte Carlo simulations |
| Elizabeth Powell1, Geoff JM Parker1,2,3, and Marco Palombo4,5 | ||
1Centre for Medical Image Computing, Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Queen Square MS Centre, Institute of Neurology, University College London, London, United Kingdom, 3Bioxydyn Limited, Manchester, United Kingdom, 4Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom, 5School of Computer Science and Informatics, Cardiff University, Cardiff, United Kingdom |
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Keywords: Diffusion/other diffusion imaging techniques, Simulations, Pseudo-diffusivity The pseudo-diffusivity effect - arising from blood flow in capillaries - is used to characterise the diffusion-weighted MRI signal at low b-values (b<200 s/mm2) in several biophysical models. We propose here a generative model for producing vascular meshes with tunable properties - such as vessel segment radius and length, and vessel volume fraction – that are compatible with common Monte Carlo diffusion simulation frameworks. Monte Carlo simulations of pseudo-diffusivity are performed, under varying conditions, by adapting the Camino simulation toolkit to include a plug flow component to spin dynamics inside the vascular mesh; the resulting signals are validated against analytical solutions. |
| 5023 | Computer 77
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SNR-Enhanced T2 and Diffusion-Weighted 3D Dual-Echo Steady-State MRI Using Random Matrix Theory-Based Denoising Reconstruction |
| Zhaohuan Zhang1, Shu-Fu Shih1, and Holden H. Wu1 | ||
1Department of Radiology, University of California, Los Angeles, Los Angeles, CA, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques Three-dimensional (3D) dual-echo steady-state (DESS) MRI can produce multi-contrast (MC)images with T2 and diffusion weighting (DW) for simultaneous T2 and D mapping in knee and prostate. A primary challenge of MC DESS is the low signal-to-noise ratio (SNR) of DW DESS leads to less reliable diffusion mapping. In this work, we investigated a new random matrix theory-based denoising reconstruction to improve MC T2W/DW DESS by taking advantages of the inherent redundancy in noise statistics across multiple coil channel and contrasts dimensions. Our in-vivo knee and prostate experiments showed promising improvements in SNR and quality of T2 and D mapping. |
| 5024 | Computer 78
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Single Shot Diffusion Trace Spectroscopic Imaging using Radial Echo Planar Trajectories |
| Andres Saucedo1,2 and M. Albert Thomas1,2 | ||
1Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States, 2Physics and Biology in Medicine Interdepartmental Graduate Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Spectroscopy, Spectroscopic Imaging We present the first demonstration of single shot diffusion trace spectroscopic imaging using radial echo planar k-space trajectories on a clinical 3T scanner. Conventional DW-MRS requires three separate acquisitions to compute the trace apparent diffusion coefficient (ADC), whereas the single shot technique generates a trace-weighted signal in one measurement, although this has so far only been applied in NMR and to a limited extent in DW-MRI. Our preliminary results indicate good agreement with expected trace ADC values both in phantom and in healthy brain, showing a promising approach for determining the orientation-independent trace ADC value with non-Cartesian diffusion-weighted spectroscopic imaging. |
| 5025 | Computer 79
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Prospective motion correction improves gSlider accelerated diffusion imaging |
| Kerrin J Pine1, Luke J Edwards1, Marianna Schmidt1,2, Juliane Damm1, Fuyixue Wang3, Susie Huang3, Evgeniya Kirilina1, and Nikolaus Weiskopf1,4 | ||
1Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Max Planck School of Cognition, Leipzig, Germany, 3A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 4Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Motion Correction, DTI High resolution diffusion weighted imaging (DWI) is required to map cortical fibres and short association fibres in superficial white matter. The recently developed gSlider sequence allows high-resolution whole-brain DWI but is prone to motion-induced artefacts due to the long volume acquisition. We combined gSlider with prospective motion correction (PMC) using optical tracking to acquire high angular, high spatial resolution DWI. In three healthy participants, we demonstrated that PMC led to a reduction of motion artifacts, an increase of temporal SNR of around 15% and better estimates of fibre characteristics in the cortex and superficial white matter. |
| 5143 | Computer 41
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Vibration Exposure in Brain MR Elastography |
| Safoura Sadegh Pour Aji Bishe1,2, Kay Pepin1,2, Jeremiah Heilman1,2, Xiang Shan1, Ziying Yin1, and Richard Ehman1 | ||
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Resoundant, Inc., Rochester, MN, United States |
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Keywords: Safety, Brain, Elastography Magnetic resonance elastography (MRE) requires application of mechanical vibrations to assess the stiffness of tissue noninvasively and quantitatively. This study assessed the levels of vibration exposure in brain tissue during a typical brain MRE exams performed for clinical research. Voxel-level vibration exposure levels throughout the brain were measured in 45 subjects in this IRB approved study. Histograms of voxel-level vibration in all cases demonstrated maximum exposure levels that were well below the very conservative EU 2002 Directive 2002/44/EC of the European Parliament guideline for total body vibration. |
| 5144 | Computer 42
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The impact of multiple sclerosis on cortical brain stiffness. |
| Helge Herthum1, Rafaela V. Silva2, Anna S. Morr3, Mehrgan Shahryari3, Matthias Anders3, Yasmine Safraou3, Stefan Hetzer1, Jürgen Braun3, Michael Scheel4, Friedemann Paul4, Carmen Infante-Duarte2, and Ingolf Sack3 | ||
1Berlin Center for Advanced Neuroimaging, Charité Universitätsmedizin Berlin, Berlin, Germany, 2Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany, 3Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany, 4Department of Neuroradiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany |
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Keywords: Elastography, Brain, Cortical stiffness Multiple sclerosis (MS) is a chronic neuroinflammatory disease that affects both white matter and cortical areas. While magnetic resonance imaging (MRI) can image pathological changes in the white matter, it is limited in quantifying cortical tissue damage in MS. Therefore, cerebral 3D-MR elastography based on multifrequency wave excitation and tomoelastography postprocessing was developed to measure cortical stiffness. We found that the cerebral cortex in MS patients is markedly softer than global brain matter and deep gray matter indicating the use of cerebral tomoelastography as a potential new imaging marker for monitoring MS disability. |
| 5145 | Computer 43
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Testing the potential of DWI-based virtual elastography in patients with brain cancer |
| Siri Fløgstad Svensson1,2, Oliver Geier1, Elies Fuster-Garcia1,3, Gunnhild Ager-Wick1, Robin Anthony Birkeland Bugge1, Anne-Hilde Farstad4, Karoline Skogen5, and Kyrre Eeg Emblem1 | ||
1Department for Physics and Computational Radiology, Oslo University Hospital, Oslo, Norway, 2Department for Physics, University of Oslo, Oslo, Norway, 3Universitat Politècnica de València, BDSLab, Instituto Universitario de Tecnologías de la Información y Comunicaciones, València, Spain, 4Department for Radiography, Oslo University Hospital, Oslo, Norway, 5Department for Radiology, Oslo University Hospital, Oslo, Norway |
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Keywords: Elastography, Elastography A previous study in the liver suggested that DWI can be used for virtual elastography. Here, we investigate the potential correlations between DWI-derived parameters and MR elastography (MRE) stiffness measurements in sixteen patients with brain cancer. The highest cross-correlation was obtained between stiffness and the shifted ADC map with b-values 1000 and 3000 s/mm² (median cross correlation 0.91). However, no correlation between mean values of MRE and sADC1000,3000 was found in normal-appearing white and gray matter, nor in tumor regions. This could be due to a too simple diffusion model and the anisotropic tissue structure of the brain. |
| 5146 | Computer 44
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Realistic simulated MR Elastography data generated from in vivo brain images |
| Dhrubo Jyoti1, Diego Caban-Rivera2, Mary Kramer2, Alexa Diano2, Curtis Johnson2, Elijah Van Houten3, Keith Paulsen1, and Matthew Mcgarry1 | ||
1Dartmouth College, Hanover, NH, United States, 2University of Delaware, Newark, DE, United States, 3University of Sherbrooke, Sherbrooke, QC, Canada |
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Keywords: Elastography, In Silico Simulations can play an important role in validating the accuracy of MR elastography (MRE) inversion algorithms. A realistic brain MRE simulation is created through a finite element model from in vivo MRE data, with 20 randomly generated simulated brains created by assigning properties of anatomical segmentations of brain structures within a range given by a published MRE atlas. Multi-frequency and multi-direction synthetic MRE data was generated via boundary conditions from in vivo measured motions to allow a range of inversion algorithms to be tested. These data will be supplied to the MRE study group for an inversion reconstruction challenge. |
| 5147 | Computer 45
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Characterization of Functional MR Elastography Responses to Variations in Visual Stimulus Frequency and Contrast |
| Harish Palnitkar1, Matthew C Murphy1, Yi Sui1, Kevin J Glaser1, Armando Manduca1, John Huston 3rd1, Richard L Ehman1, and Arvin Arani1 | ||
1Department of Radiology, Mayo Clinic, Rochester, MN, United States |
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Keywords: Elastography, Elastography, Functional MR Elastography The response of BOLD fMRI to changes in both visual contrast frequency and contrast intensity have been well documented. Recently, an increase in the stiffness of activated regions of the visual cortex due to a controlled variation of block duration has been demonstrated with fMRE elastograms. The current study aims to investigate the relationship between BOLD fMRI and fMRE due to a controlled variation of both contrast intensity and contrast frequency of a visual stimulation. This study demonstrates that the fMRE-measured stiffness change varies linearly with the underlying neural activity, which can be modulated by stimulus parameterization. |
| 5148 | Computer 46
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A Biomechanical Analysis Framework for Co-Correlation of 7T MR Elastography Measures and Amyloid Beta Deposition |
| Emily Triolo1, Mackenzie Langan2,3, Oleksandr Khegai2, Akbar Alipour2, Carolina Ferreira-Atuesta3, Aymeric Pionteck1, Jonathan Sutkowski3, Trey Hedden3, Priti Balchandani2, and Mehmet Kurt1,2 | ||
1Mechanical Engineering, University of Washington, Seattle, WA, United States, 2Biomedical Engineering and Imaging Institute, Ichan School of Medicine at Mount Sinai, New York City, NY, United States, 3Graduate School of Biomedical Sciences, Ichan School of Medicine at Mount Sinai, New York City, NY, United States |
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Keywords: Elastography, Brain, 7T, Alzheimer's Disease, PET Previous studies have implied the future use of MRE metrics to track disease progression and as a tool for AD diagnosis, potentially replacing or augmenting methods that use ionizing radiation. In this pilot study, we have therefore developed a novel framework for performing ultrahigh field (7T) MRE at high resolution on subjects who have previously undergone PET scans and performing joint analysis of biomechanical and pathologic markers on these subjects. We have successfully created a framework for measurement of high-resolution brain mechanical properties for co-correlation with traditional PET measures to be used on AD patients in the future. |
| 5149 | Computer 47
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Development of in vivo human brain multifrequency DTIMRE (mDTIMRE) |
| Shujun Lin1, Bradley Sutton2, Richard Magin1, Aaron Anderson2, and Dieter Klatt1 | ||
1Biomedical Engineering, University of Illinois Chicago, Chicago, IL, United States, 2Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, United States |
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Keywords: Elastography, Elastography Simultaneous acquisition of diffusion tensor imaging and multifrequency magnetic resonance elastography was examined in this preliminary study on in vivo human brain. The mDTIMRE was achieved by ensuring the same diffusion encoding using experiment parameters with different mechanical frequencies, while fulfilling the timing condition of simultaneous acquisition. By applying a multifrequency dual elasto-visco inversion approach, the effective image resolution of mechanical property maps is improved and enables quantitatively assessment of tissue properties in brain sub-regions. The experiment results show a good correlation between mDTIMRE and conventional measurements. |
| 5150 | Computer 48
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Transversely Isotropic MR Elastography with a Power Law Multi-Frequency Reconstruction |
| Diego A. Caban-Rivera1, Elijah E. W. Van Houten2, Matthew D. J. McGarry3, L. Tyler Williams1, Phil V. Bayly4, Keith D. Paulsen3, and Curtis L. Johnson1 | ||
1Biomedical Engineering, University of Delaware, Newark, DE, United States, 2Département de Génie Mécanique, Université de Sherbrooke, Sherbrooke, QC, Canada, 3Thayer School of Engineering, Dartmouth College, Hanover, NH, United States, 4McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, United States |
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Keywords: Elastography, Brain This study combined multiexcitation MRE (ME-MRE), and multifrequency MRE (MF-MRE) with a transversely isotropic nonlinear inversion (TINLI) and axonal fiber directions from diffusion tensor imaging to investigate anisotropic and frequency-dependent material properties simultaneously. These preliminary results show that multifrequency-TINLI MRE can be readily applied to in vivo human data at distinct frequencies. |
| 5151 | Computer 49
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Response of Brain Tissue Mechanical Properties to Applied Pre-Strain in Magnetic Resonance Elastography |
| Olivia M Bailey1, Alexa M Diano1, Ali H Lateef1, Elise A Corbin1, and Curtis L Johnson1 | ||
1Biomedical Engineering, University of Delaware, Newark, DE, United States |
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Keywords: Elastography, Traumatic brain injury This study uses magnetic resonance elastography (MRE) with incremental compression to measure the apparent viscoelastic properties of bovine brain tissue as pre-strain is applied. Results from our tissue-agar phantom showed an increase in stiffness, and a decrease in damping ratio for the bovine brain. The agar showed an increase in stiffness and no consistent change in damping ratio. This research serves as the foundation for future studies measuring the nonlinear properties of human cadaveric brain tissue. Output from this work will be instrumental in advancing current traumatic brain injury (TBI) models. |
| 5152 | Computer 50
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Anisotropic MR elastography with a DTI-informed crossing fiber mechanical model |
| Matthew Mcgarry1, Damian Sowinski1, Diego Caban-Rivera2, Elijah Van Houten3, Curtis Johnson2, Keith Paulsen1, and Philip Bayly4 | ||
1Dartmouth College, Hanover, NH, United States, 2University of Delaware, Newark, DE, United States, 3University of Sherbrooke, Sherbrooke, QC, Canada, 4Washington University in St Louis, St Louis, MO, United States |
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Keywords: Elastography, White Matter Anisotropic MRE has shown some promise in estimating mechanical properties of fiber-reinforced biological tissues. However, these methods are restricted to modeling a single fiber and ignores complexity that occurs such as regions of brain white matter with crossing fibers. Here we implement an inversion algorithm capable of modeling material with two fiber directions obtained from diffusion MRI in order to reduce model data mismatch and provide fiber-specific properties, which may show promise in correlating with brain health and function. Performance of this algorithm is demonstrated in simulation and in vivo brain data and compared with one-fiber and zero-fiber (isotropic) inversions. |
| 5153 | Computer 51
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Improved Brain MRE Performance on a Compact, Lightweight 3T Scanner with High-Performance Gradients |
| Yi Sui1, Matthew C. Murphy1, Ziying Yin1, Kevin J. Glaser1, Richard L. Ehman1, Matt A. Bernstein1, John Huston III1, and Yunhong Shu1 | ||
1Department of Radiology, Mayo Clinic, Rochester, MN, United States |
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Keywords: Elastography, Brain, MRE, Compact 3T We conducted a direct comparison of Brain MRE performance between a compact, lightweight 3T scanner (C3T) and a whole-body scanner (WB3T). We demonstrate in phantom and volunteers that the C3T scanner provides superior image quality and scanning efficiency for commonly performed brain MRE pulse sequences, especially for higher-resolution scanning. |
| 5154 | Computer 52
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EMPIRE: Elastographic Magnetization Prepared Imaging with Rapid Encoding |
| Alex M Cerjanic1,2, Alexa M Diano2, Matthew DJ McGarry3, and Curtis L Johnson2 | ||
1Department of Medicine, Massachusetts General Hospital, Boston, MA, United States, 2Department of Biomedical Engineering, University of Delaware, Newark, DE, United States, 3Dartmouth College, Hanover, NH, United States |
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Keywords: Elastography, Data Acquisition This study demonstrates the use of magnetization preparation for MR elastography in combination with a 3D GRE stack of spirals pulse sequence. By decoupling the motion encoding from the readouts, rapid encoding strategies, such as 3D GRE, can be used. MRE images, displacement, and inverted elastograms are obtained on in vivo human brain. 3D GRE readouts with EMPIRE motion encoding can acquire a complete MRE dataset 33% faster than 2D SE-EPI with similar parallel imaging acceleration factors. |
| 5155 | Computer 53
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Mesenteric Adipose Tissue in Crohn’s Disease assessed by in vivo MR Elastography |
| Rolf Reiter1, Florian Nino Loch2, Carsten Kamphues3, Mehrgan Shahryari1, Stephan Rodrigo Marticorena Garcia1, Britta Siegmund4, Carl Weidinger4, Anja Kühl5, Bernd Hamm1, Jürgen Braun6, Ingolf Sack1, Patrick Asbach1, and Laura Jensen1 | ||
1Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 2Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany, 3Surgery, Parkklinik Weißensee, Berlin, Germany, 4Gastroenterology, Infectious Diseases and Rheumatology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 5iPATH.Berlin-Immunopathology for Experimental Models, Charité - Universitätsmedizin Berlin, Berlin, Germany, 6Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany |
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Keywords: Elastography, Body, inflammatory bowel disease Despite increasing evidence that the functional involvement and structural changes of mesenteric adipose tissue influence the course of Crohn's disease, its viscoelastic properties remain elusive. We demonstrate the feasibility of in vivo MR elastography of mesenteric adipose tissue and present preliminary reference values for Crohn's disease patients and healthy controls in this explorative study. Our preliminary results show an excellent diagnostic performance in detecting Crohn's disease by assessing the viscoelastic properties of mesenteric adipose tissue using histopathology of surgical specimens as reference. Our results motivate further studies for the biophysical characterization of mesenteric adipose tissue in inflammatory bowel disease. |
| 5156 | Computer 54
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Intrinsic MR elastography for classification of focal liver lesions using normalized viscoelastic parameters: a pilot study |
| Amirhosein Baradaran Najar1,2, Elige Karam2,3, Guillaume Gilbert4, Maxime Barat2,3, Emmanuel Montagnon3, Hélène Castel5, Jeanne-Marie Giard5, Bich Nguyen6, Guy Cloutier2,7,8, An Tang2,7, and Elijah Van Houten1,9 | ||
1Département du génie mécanique, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada, 3Department of Radiology, Radiation Oncology and Nuclear Medicine, Université de Montréal, Montréal, QC, Canada, 4Philips Healthcare, Mississauga, ON, Canada, 5Centre Hospitalier de l’Université de Montréal (CHUM), Montréal, QC, Canada, 6Service of Pathology, Centre Hospitalier de l’Université de Montréal (CHUM), Montréal, QC, Canada, 7Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada, 8Laboratory of Biorheology and Medical Ultrasonics(LBUM), Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada, 9Centre de recherche du Centre hospitalier de l'Université de Sherbrooke (CRCHUS), Sherbrooke, QC, Canada |
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Keywords: Elastography, Elastography, Intrinsic magnetic resonance elastography, Cancer Intrinsic activation MR elastography (iMRE) method has been applied to a cohort of patients undergoing liver MRI for assessment of focal liver lesions. We used segmentation, masking, and normalization of viscoelastic parameters to investigate the capability of this method to differentiate benign and malignant liver lesions. The normalized storage modulus (G') computed by nonlinear inversion-iMRE showed significant differences between benign and malignant lesions. |
| 5157 | Computer 55
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Quantifying inhomogeneity of kidney, liver and muscle before and after the freeze-thaw cycle using 1-Norm waveform analysis and MR elastography |
| Rolf Reiter1,2, Harish Palnitkar3, Shreyan Majumdar4, Joseph Crutison4, Shujun Lin4, Thomas J. Royston4, and Dieter Klatt4 | ||
1Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 2BIH Biomedical Innovation Academy, BIH Charité Digital Clinician Scientist Program, Berlin Institute of Health at Charité – Universitätsmedizin Berlin, Berlin, Germany, 3Radiology, Mayo Clinic, Rochester, MN, United States, 4Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL, United States |
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Keywords: Elastography, Tissue Characterization The recently developed 1-Norm technique can be used to quantify the extend of scattering of mechanical waves generated by inhomogeneities. This explorative study shows that 1-Norm can detect mechanical inhomogeneity of ex vivo kidney, liver and muscle without the need to use ill-posed wave inversion techniques. The 1-Norm technique has potential to serve as an MRE-based diagnostic biomarker independent of stiffness for the characterization of pathological conditions associated with changes in tissue mechanical inhomogeneity. |
| 5158 | Computer 56
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Sagittal free-breathing MR elastography of the pancreas with motion-correction at 3T |
| Anne-Sophie van Schelt1,2, Nienke Petronella Maria Wassenaar1, Jurgen H. Runge1, Jaap Stoker1,2,3, Aart J Nederveen1, and Eric M Schrauben1 | ||
1Radiology and Nuclear Medicine, Amsterdam UMC, location AMC, Amsterdam, Netherlands, 2Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, Netherlands, 3Endocrinology, Metabolism, Amsterdam Gastroenterology, Amsterdam, Netherlands |
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Keywords: Elastography, Pancreas Breathing motion can be detrimental to quantitative accuracy in pancreatic MR elastography (MRE). We investigated motion-correction strategies on sagittal multi-frequency free-breathing SE-EPI MRE acquisitions to mitigate breathing-motion and increase accuracy. Breathing-states were determined through a respiratory-belt and multiple number of bins were tested. Three intensity-based registration methods (with and without non-rigid post-processing) and non-rigid registration were ranked on MRE quality measures. The best method showed improved data quality, inversion precision and repeatability compared to no correction, but resulted in apparently increased shear wave speed (SWS), which warrants further investigation. |
| 5159 | Computer 57
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MRE navigator for rapid estimation of liver stiffness. |
| Matthias Anders1, Carsten Warmuth1, Josef Pfeuffer2, Heiko Tzschätzsch1, Helge Herthum1, Katja Degenhardt3, Oliver Wieben4, Sebastian Schmitter3, Jeanette Schulz-Menger1,5,6, Jürgen Braun1, and Ingolf Sack1 | ||
1Charité - Universitätsmedizin Berlin, Berlin, Germany, 2MR Application Development, Siemens Healthcare, Erlangen, Germany, 3Physikalisch-Technische Bundesanstalt(PTB), Braunschweig and Berlin, Berlin, Germany, 4University of Wisconsin, Madison, WI, United States, 5Experimental and Clinical Research Center (ECRC), DZHK partner site Berlin, Berlin, Germany, 6HELIOS Klinikum Berlin Buch, Berlin, Germany |
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Keywords: Elastography, Data Acquisition MR elastography (MRE) can noninvasively detect liver fibrosis based on elevated stiffness values. However, a complete MRE scan is time-consuming and typically extends over multiple breath-holds. Therefore, a multi-shot gradient echo sequence with spiral readout was developed to provide full two-dimensional elastograms of the liver in less than one second. The new sequence can be used as an MRE navigator to provide immediate feedback on wave penetration and data consistency for parameter optimization prior to running full multi-dimensional MRE. Moreover, the method can be used to rapidly track potential changes in liver stiffness such as those induced by respiration. |
| 5160 | Computer 58
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Repeatability of multifrequency MR elastography in pancreatic ductal adenocarcinoma patients and healthy volunteers |
| Nienke P.M. Wassenaar1,2, Anne-Sophie van Schelt1,2, Eric M. Schrauben1, Hanneke W.M. van Laarhoven2,3, Jaap Stoker1,2, Aart J. Nederveen1, and Jurgen H. Runge1 | ||
1Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands, 2Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, Netherlands, 3Medical Oncology, Amsterdam University Medical Centers, Amsterdam, Netherlands |
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Keywords: Elastography, Pancreas MR elastography (MRE) could be useful as an imaging biomarker in pancreatic cancer. To this end, pancreatic MRE parameters should be repeatable and be able to differentiate between healthy and tumour tissue. In this study, 10 patients with pancreatic ductal adenocarcinoma and 8 sex- and age-matched healthy volunteers underwent three MRE scans in a test-retest set-up. Results showed that MRE parameters were repeatable in patients and healthy volunteers. Furthermore, a significant increase in shear wave speed was found in pancreatic tumours compared to healthy pancreatic tissue. |
| 5161 | Computer 59
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Imaging of Propagating Broadband Transient Waves with Multi-scale MR Elastography Motion Encoding: A Validation Study |
| Yuan Le1, Jun Chen1, Phillip J. Rossman1, Armando Manduca1, Kevin J. Glaser1, Bradley D. Bolster Jr.2, Stephan Kannengiesser3, and Richard L. Ehman1 | ||
1Radiology, Mayo Clinic, Rochester, MN, United States, 2US MR R&D Collaboration, Siemens Medical Solutions Inc., Salt Lake City, UT, United States, 3MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany |
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Keywords: Elastography, Elastography, Transient wave, multi-scale encoding We demonstrate imaging of the propagation of transient waves using multi-scale motion encoding gradient waveforms. Displacement values are calculated using the inverse Haar transforms. We validated the results by comparison with wave images obtained using standard MRE acquisition and processing. The approach provides the ability to image broadband motion more efficiently and accurately compared with previous methods and promises to be a useful approach for biomechanical studies of traumatic brain injury. |
| 5162 | Computer 60
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Utilizing MR Elastography to Visualize Higher Harmonic Components of Wave Propagation in Phantoms with Interfaces |
| Emily Triolo1, Melih Eriten2, Curtis Johnson3, and Mehmet Kurt1,4 | ||
1Mechanical Engineering, University of Washington, Seattle, WA, United States, 2Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, United States, 3Biomedical Engineering, University of Delaware, Newark, DE, United States, 4Biomedical Engineering and Imaging Institute, Ichan School of Medicine at Mount Sinai, New York City, NY, United States |
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Keywords: Elastography, Phantoms, Wave Propagation, Biointerface While MRE can be used to calculate mechanical properties of tissue, bio-interfaces can cause distortions in the shear-wave propagation patterns which are difficult to account for with current MRE techniques. Therefore, we utilized three specialized MRE sequences to visualize the first three harmonics of wave propagation in phantoms with simulated bio-interfaces. We were able to measure the doubling and tripling of wave number in the phantoms excited at the fundamental vibration frequency using this optimized MRE protocol. We characterized differences in wave propagation at higher harmonics along phantom interfaces, and observed substantial differences in wave characteristics based on adhesion level. |
| 5163 | Computer 61
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Implicit Regularization for Improving Phase-based EPT with Stein’s Unbiased Risk Estimator |
| Chuanjiang Cui1, Kyu-Jin Jung1, Jun-Hyeong Kim1, and Dong-Hyun Kim1 | ||
1Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea, Republic of |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties Phase-based EPT algorithm is extremely sensitive to noise. Although various denoising algorithms have been introduced to suppress noise amplification, residual artifact cause instability conductivity error or broadening boundary artifact. In this work, we propose a novel generative network trained with Stein’s unbiased risk estimator under the purely unsupervised learning framework, which improve the performance of phase-based conductivity reconstruction algorithms. In addition, the proposed method does not need any dataset for training neural network and not require any prior information for designing explicit regularization. |
| 5164 | Computer 62
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Investigating Variable Density Sampling Patterns in Spiral Trajectories for use in MREPT |
| Safa Özdemir1,2, Efe Ilicak1,2, Lothar R. Schad1,2, and Frank G. Zöllner1,2 | ||
1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 2Mannheim Institute for Intelligent Systems in Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties Magnetic Resonance Electrical Properties Tomography (MREPT) is used for obtaining conductivity by utilizing B1 phase images. In order to obtain B1 phase, different pulse sequences can be used. Among these, spiral trajectory based imaging has various advantages including high SNR efficiency and acquisition speed and was demonstrated in MREPT previously. In this work, to further improve spiral trajectory based imaging in MREPT, we investigate variable density sampling patterns. In vivo brain results indicate that conductivity images are quite robust with the choice of undersampling pattern and whole brain coverage can be completed under a minute with multiple averages. |
| 5165 | Computer 63
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Simultaneous Estimation of Electrical Properties and Incident Fields Using Global Maxwell Tomography with B1+ and MR Signal Data |
| Jose E. C. Serralles1, Ilias I. Giannakopoulos2, Georgy D. Guryev1, Luca Daniel1, and Riccardo Lattanzi2 | ||
1Research Laboratory of Electronics (RLE), Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2The Bernard and Irene Schwartz Center for Biomedical Imaging (CBI), Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties We propose a novel approach to electrical property (EP) estimation that also estimates the incident fields generated by a coil, by solving a basis pursuit problem. We also propose a novel Global Maxwell Tomography (GMT) formulation that uses the MR signal instead of $$$B_1^+$$$. We tested our approach experimentally by reconstructing the average EP of a homogeneous cylinder. We obtained < 5% estimation error using only $$$B_1^+$$$ data obtained from MR Fingerprinting. We then estimated the receive sensitivity maps $$$B_1^-$$$ by using the new signal-based GMT. |
| 5166 | Computer 64
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Brain water-content based Electrical Properties Tomography in healthy volunteers, tumor and multiple sclerosis patients |
| Stefano Mandija1,2, Sarah Jacobs3, Jordi Kleinloog1,2, Hongyan Liu1,2, Oscar van der Heide1,2, Anja van der Kolk1,4, Alessandro Sbrizzi1,2, and Cornelis van den Berg1,2 | ||
1Department of Radiotherapy, UMC Utrecht, Utrecht, Netherlands, 2Computational Imaging Group for MR Therapy and Diagnostics, UMC Utrecht, Utrecht, Netherlands, 3Department of Radiology, UMC Utrecht, Utrecht, Netherlands, 4Department of Medical Imaging, Radboud UMC, Nijmegen, Netherlands |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties, Conductivity In this work, we first extend the validation of the water-content based Electrical Properties Tomography (wEPT) model from brain white matter to gray matter conductivity reconstructions in healthy volunteers. Secondly, we show that wEPT reconstructions calibrated on 10 healthy volunteers from an MR-STAT clinical trial dataset show a conductivity increase in pathological regions for 6 primary brain tumor and 9 multiple sclerosis (MS) patients from the same study. For diffuse glioma, a positive correlation between grade and conductivity is observed. For MS white matter lesions a clear conductivity increase is observed compared to healthy white matter. |
| 5167 | Computer 65
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Measurement of Extracellular Electrical Conductivity Using Conductivity Tensor Imaging |
| Bup Kyung Choi1, Nitish Katoch1, Ji Ae Park2, Tae Hoon Kim3, Young Hoe Hur4, Jin Woong Kim5, and Hyung Joong Kim1 | ||
1Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea, Republic of, 2Division of Applied RI, Korea Institute of Radiological and Medical Science, Seoul, Korea, Republic of, 3Medical Convergence Research Center, Wonkwang University Hospital, Iksan, Korea, Republic of, 4Department of Hepato-Biliary-Pancreas Surgery, Chonnam National University Medical School, Gwangju, Korea, Republic of, 5Department of Radiology, Chosun University Hospital and Chosun University College of Medicine, Gwangju, Korea, Republic of |
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Keywords: Electromagnetic Tissue Properties, Electromagnetic Tissue Properties, Electrical Conductivity, Low-frequency conductivity, High-field MRI, Tissue properties, Cell density imaging Conductivity measured at low-frequency can provide information on extracellular space (ECS), which will be useful in clinical applications such as tumor imaging and bioelectromagnetic modeling. Recently proposed conductivity tensor imaging (CTI) technique provides the anisotropic low-frequency conductivity distribution extracted from high-frequency conductivity measurement from the B1 map of MRI. The extracellular conductivity measured using CTI from three phantoms was compared with an impedance analyzer. The accuracy of the CTI technique was estimated to be high enough for most clinical applications. |
| 5168 | Computer 66
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Simultaneously Applying Multiple Diffusion Models to Predict Histologic Grade of Bladder Urothelial Carcinoma |
| Junting Guo1, Lu Zhang1, Shuo Li1, Ding Li1, Zhichang Fan1, Meining Chen2, Guoqiang Yang3, Yan Li3, Le Wang3, Bin Wang3, and Xiaochun Wang3 | ||
1College of Medical Imaging, Shanxi Medical University, Taiyuan, China, 2MR Scientific Marketing, Siemens Healthcare, Shanghai, China, 3Department of Radiology, The First Hospital of Shanxi Medical University, Taiyuan, China |
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Keywords: Multi-Contrast, Cancer Tumor grading is the most important single prognostic factor for bladder urothelial carcinoma. In this study, we compared 5 diffusion models for assessing low- and high-grade in bladder urothelial carcinoma, including continuous-time random-walk (CTRW), incoherent motion within the voxel (IVIM), stretched exponential model (SEM), diffusion kurtosis imaging (DKI) and fractional-order calculus (FROC). The study found that CTRW_D, DKI_Dapp, DKI_Kapp, FROC_D, IVIM_D and SEM_DDC were significantly different between low- and high-grade bladder urothelial carcinoma and could distinguish one from the other. |
| 5169 | Computer 67
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Determination of optimal parameters for accelerated whole-body diffusion-weighted imaging (WB-DWI) using simultaneous multi-slice (SMS) |
| Sam Keaveney1,2, Alina Dragan1, Julie Hughes1, Mihaela Rata1,2, Thomas Benkert3, Christina Messiou1,2, Dow-Mu Koh1,2, and Jessica M Winfield1,2 | ||
1MRI Unit, Royal Marsden NHS Foundation Trust, Sutton, United Kingdom, 2Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom, 3MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Whole Body, Simultaneous Multi-Slice Simultaneous multi-slice (SMS) has the potential to accelerate whole-body diffusion-weighted imaging (WB-DWI). This work presents quantitative and qualitative assessment of SMS image quality in phantoms and healthy volunteers, as a strategy to determine the optimal parameters for the clinical application of a research application SMS sequence. An SMS factor of 2 and a moderately reduced TR did not introduce significant bias to ADC measurements. The reduction in SNR for these acquisitions was statistically, but not clinically, significant. These parameters offer time savings of up to 24% with respect to non-SMS settings and should be investigated further in a patient population. |
| 5170 | Computer 68
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New biomaterial for 3D cell modeling and NMR analysis: low signal interference and high diffusion for robust metabolic studies in-vitro |
| Alba Herrero Gómez1, Marc Azagra1, and Irene Marco Rius1 | ||
1Institute for Bioengineering of Catalonia, Barcelona, Spain |
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Keywords: Molecular Imaging, New Devices Due to its non-invasive nature, NMR has become a pillar as a diagnostic technique, as well as a support for biochemical assays and disease tracking both in vivo and in-vitro. However, due to its magnetic susceptibility, some of the materials used for tissue engineering and 3D cell modeling are incompatible with the technique, interfering with data acquisition and reducing its applications in-vitro. We developed a cryogel that could help bridge this gap between NMR and tissue engineering. |
| 5171 | Computer 69
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Fast consensus optimisation in diffusion MRI modeling |
| Samuel St-Jean1 and Markus Nilsson1 | ||
1Clinical Sciences Lund, Lund University, Lund, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Data Analysis, diffusion modeling This work explores how to obtain parameter maps from a diffusion MRI model under 30 seconds and how to leverage multiple plausible solutions into a consensus solution using a framework similar to MR fingerprinting. The method is tested with a two compartments model and a mean kurtosis model and compared with a standard optimisation solver. Visual improvements are shown on parameter maps, showing less implausible values than the standard method, but without the use of constraints or assumptions. Access to a distribution of plausible values allows to compute most likely value from this distribution in the case of parameter degeneracies. |
| 5172 | Computer 70
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Spiral readout improves in vivo MR axon radius estimation in human white matter |
| Marten Veldmann1, Luke J. Edwards2, Kerrin J. Pine2, Philipp Ehses1, Nikolaus Weiskopf2,3, and Tony Stöcker1,4 | ||
1MR Physics, Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 3Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany, 4Department of Physics & Astronomy, University of Bonn, Bonn, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques We compared spiral and EPI diffusion imaging at ultra-high b-values for axon radius estimation in the white matter. For data acquisition, a custom multiband spiral sequence was combined with trajectory monitoring and higher order image reconstruction. The lower echo time of the spiral sequence led to increased relative SNR compared to EPI and improved estimation of axon radii. The resulting axon radius maps from spiral scans were more homogeneous especially in low-SNR regions. We also found, that denoising performed on complex data instead of magnitude data significantly improved axon radius estimation. |
| 5173 | Computer 71
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Multi-orientation ZOOMit diffusion-weighted imaging in the preoperative T staging of gastric cancer |
| Wei-Yue Xu1, Qiong Li1, Ya-Jun Hou1, Yi-Cheng Hsu2, Thomas Benkert3, Yu-Dong Zhang1, and Xi-Sheng Liu1 | ||
1Department of Radiology, the First Affiliated Hospital with Nanjing Medical University, Nanjing, China, 2MR Collaboration, Siemens Healthineers Ltd, Shanghai, China, 3MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques, ZOOMit diffusion-weighted imaging Magnetic resonance imaging has been demonstrated to be a useful tool in the preoperative diagnosis of gastric cancer. With improved imaging quality and flexible imaging orientation, ZOOMit diffusion-weighted imaging (DWI) is attracting attention in gastric tumor imaging. The stomach is a hollow organ with variable morphology. Thus, multi-orientation ZOOMit DWI imaging provides a complete view of the lesion compared with axial DWI, thus leading to more accurate preoperative staging in treatment strategy determination. |
| 5174 | Computer 72
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Diffusion imaging on a 0.35 T MRI-guided linear accelerator providing accurate in vivo apparent diffusion coefficient maps |
| Joseph Weygand1, Tess Armstrong2, J.M. Bryant1, Jacqueline Andreozzi1, Ibrahim M. Oraiqat1, Casey L. Liveringhouse1, Kujtim Latifi1, Kosj Yamoah1, James R. Costello3, Eduardo G. Moros1, Issam M. El Naqa4, Arash O. Naghavi1, Stephen A. Rosenberg1, and Gage Redler1 | ||
1Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, United States, 2Department of Product Development, ViewRay, Oakwood Village, OH, United States, 3Department of Radiology, Moffitt Cancer Center, Tampa, FL, United States, 4Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, United States |
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Keywords: Diffusion/other diffusion imaging techniques, Radiotherapy Diffusion weighted imaging (DWI) allows for the evaluation of tumor cellularity. Its application on a 0.35 T MRI-guided linear accelerator (MRL) would facilitate integration of this information into radiotherapy planning and potentially allow for online biologically-guided plan adaption. This study demonstrates the capability of a DWI protocol both in phantom and in vivo. In particular, it is demonstrated that quantitively accurate, repeatable, and geometrically precise ADC maps can be produced in phantom on the 0.35 T MRL. Additionally, this technique was applied in vivo on one sarcoma patient receiving same-day diagnostic diffusion scans before, during, and after radiotherapy. |
| 5175 | Computer 73
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Integrating intravoxel incoherent motion and diffusion tensor MRI of the brain into a single fast acquisition - a model-selection study |
| Olaf Dietrich1, Mengfei Cai2, Anil Tuladhar2, Mina Jacob2, Gerald Drenthen3, Jacobus Jansen3,4, José Marques2, Jens Ricke1, Frank-Erik de Leeuw2, Marco Duering5, and Walter Backes3 | ||
1Department of Radiology, LMU University of Munich, Munich, Germany, 2Department of Neurology, Donders Center for Medical Neurosciences, Radboud University Medical Center, Nijmegen, Netherlands, 3Schools for Mental Health and Neuroscience (MHeNs) and Cardiovascular Diseases (CARIM), Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, 4Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 5Medical Image Analysis Center (MIAC AG) and qbig, Department of Biomedical Engineering, University of Basel, Basel, Switzerland |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion Tensor Imaging, Intravoxel incoherent motion MRI; Model selection; Brain; Cerebral small vessel disease The acquisition of IVIM and DTI data of the brain can be integrated into a single measurement, which offers the possibility to determine orientation-dependent (tensorial) perfusion parameters in addition to established IVIM and DTI parameters. The purpose of this study was to evaluate the feasibility of such an integrated IVIM-DTI protocol with a clinically feasible scan time below 6 minutes and to establish the maximum number of DTI and IVIM tensor parameters that can reliably be determined with this approach by comparing 17 different IVIM-diffusion models with 4 to 19 model parameters. |
| 5176 | Computer 74
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Soft-Tissue Sarcomas demonstrate Fractional Anisotropy in Diffusion Tensor Imaging and Fractional Anisotropy Values Change After Treatment |
| Imogen Thrussell1,2, Jessica Winfield1,2, Sadiq Usman2, Jennifer Newman2, Georgina Hopkinson2, Shane Zaidi1,2, Aisha Miah1,2, Christina Messiou1,2, and Matthew Blackledge1,2 | ||
1The Institute of Cancer Research, London, United Kingdom, 2The Royal Marsden NHS Foundation Trust, London, United Kingdom |
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Keywords: Diffusion/other diffusion imaging techniques, Diffusion Tensor Imaging, Cancer, Fractional Anisotropy, DWI, ADC In previous studies average values of Apparent Diffusion Coefficient (ADC) have been shown to change significantly after radiotherapy in Soft-Tissue Sarcomas (STS). In this study we evaluate the Fractional Anisotropy (FA) of STS before and after treatment and demonstrate that (i) tumours can exhibit significant diffusion anisotropy, and (ii) changes in FA are inversely correlated with ADC change. Diffusion-Tensor Imaging (DTI) may therefore provide important microstructural information when interpreting change in STS after radiotherapy, and that diffusion anisotropy should be accounted for when optimising diffusion-weighted imaging (DWI) protocols for STS. |
| 5177 | Computer 75
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Does MADI Detect Temporal Brain Metabolic Activity Changes? |
| Martin M. Pike1, Xin Li1, Eric Baetscher1, Thomas M. Barbara1, Manoj K. Sammi1, Alexander A. Stevens1, and Charles S. Springer1 | ||
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States |
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Keywords: Molecular Imaging, Metabolism, Activity Metabolic Activity Diffusion Imaging [MADI] maps on-going sodium pump metabolic flux. Here, we investigate the question as to whether MADI can detect temporal changes of this activity in sequential acquisitions from the healthy human brain. |
| 5178 | Computer 76
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Time-dependence of perfusion fraction with flow-compensated intravoxel incoherent motion MRI in the brain |
| Louise Rosenqvist1, Mikael Montelius1, Maria Ljungberg1,2, and Oscar Jalnefjord1,2 | ||
1Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, 2Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden |
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Keywords: Diffusion/other diffusion imaging techniques, Perfusion, IVIM Using IVIM imaging for completely non-invasive perfusion MRI is gaining popularity. IVIM perfusion assessment depends not only on capillary network characteristics, but also on diffusion encoding-time. In this study, a flow-compensated pulse sequence with variable encoding-time was implemented and validated through phantom measurements, and subsequently used to study the encoding-time dependence of IVIM perfusion fraction in human brain tissue. Initial findings indicate a decrease in perfusion fraction as encoding-time increases. |