Ye Tian¹, Weiyi Chen¹, Dani Byrd², Shrikanth Narayanan^1,2, and Krishna S. Nayak^1
1Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States, ²Department of Linguistics, University of Southern California, Los Angeles, CA, United States

Real-time MRI plays an important role in studying articulator movements during typical and atypical human speech. Recently, real-time tagging methods were developed to reveal inner tongue movements, including deformations in the body of the tongue that were previously unobservable. Here, we demonstrate tracking of tongue deformations and estimation of tongue strain from real-time tagging, using a motion-compensated total generalized variation reconstruction and optical flow. Optical flow tracking has an averaged error of 1.10±0.83mm, compared with manually tracked tagged line intersections, while intra-observer variability is 0.80±0.49mm. The estimated tongue deformation and strain maps provide for linguistically sensible interpretation.

Alexs A Matias¹, Corinna F Serviente^1,2, Stephen T Decker¹, Muhammet E Erol¹, Gaia Giuriato ³, Yann Le Fur⁴, Rajakumar Nagarajan ⁵, and Gwenael Layec^1,6
1Kinesiology, University of Massachusetts at Amherst, Amherst, MA, United States, ²Center for Health and Human Performance, Institute for Applied Life Sciences, University of Massachusetts at Amherst, Amherst, MA, United States, ³Neuroscience, Biomedicine, and Movement Science, University of Verona, Verona, Italy, ⁴Centre de Resonance Magnetique Biologique et Medicale, Marseille, France, ⁵Human Magnetic Resonance Center, Institute for Applied Life Sciences, University of Massachusetts at Amherst, Amherst, MA, United States, ⁶Institute for Applied Life Sciences, University of Massachusetts at Amherst, Amherst, MA, United States

Alkaline inorganic phosphate (Pi_alk) is a promising biomarker of mitochondrial content in vivo that is technically challenging to assess at 3T. The absolute and relative reproducibility of Pi_alk in the quadriceps muscle across two visits were assessed in healthy sedentary-to-moderately active young adults using ³¹P-MRS at 3T. The results of this study demonstrate an excellent absolute and relative reproducibility of the quantification of Pialk in the quadriceps muscle at 3T provided that the coil is positioned at the mid-thigh. 

Xingyu Zhou^1,2, Carly Lockard^2,3, Melissa Hooijmans⁴, and Bruce Damon^2,3
1Biomedical Engineering, Vanderbilt University, Nashvill, TN, United States, ²Carle Clinical Imaging Research Program, Carle Health, Urbana, IL, United States, ³Stephens Family Clinical Research Institute, Carle Health, Urbana, IL, United States, ⁴Amsterdam University Medical Center, Amsterdam, Netherlands

Diffusion-tensor imaging (DTI) based fiber tractography is a useful tool to study the architecture of human skeletal muscle. However, effects of image acquisition and analysis conditions on the outcome of architectural estimates are challenging to examine in vivo. In this work, we describe a numerical simulation framework where the ground truth of muscle architecture is known and the outcome can be tested under different conditions. Results show that the estimate of fiber curvature is most affected by image noise. While second-order polynomial fitting of fiber tracts is more robust to image noise, third-order fitting performs better on highly curved fibers.

Alan E. Rivera-Garcia¹, Jay D. Turner², Juan Uribe², Richard D. Dortch¹, John C. Gore³, and Ping Wang^1
1Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States, ²Barrow Neurological Institute, Phoenix, AZ, United States, ³Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States

R1rho imaging can provide novel information on dynamic processes within tissues, allowing for a more comprehensive analysis of the parameters of chemical exchange and/or intrinsic microstructure. We measured the dispersion of R1rho with different locking fields in the major lumbar muscles of psoas, paraspinal muscles (multifidus and erector spinae), and quadratus lumborum. The results showed that R1rho dispersion is significant and measurable at 3T which may provide a new way to characterize muscles involved in low back pain.

Ryan Wahidi¹, Yi Zhang², Ran Li¹, Mohammed A. Zayed³, Mary K. Hastings⁴, and Jie Zheng^1
1Radiology, Washington University School of Medicine, St. Louis, MO, United States, ²Zhejiang University, Hangzhou, China, ³Department of Surgery, Section of Vascular Surgery, Washington University School of Medicine, St. Louis, MO, United States, ⁴The Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO, United States

The objective of this study is to analyze the efficacy of quantitative PCr MRI in quantifying differing muscle tissue PCr kinetics in healthy individuals and diabetic patients. Healthy subjects and diabetic patients underwent PCr and perfusion imaging in calf muscle at rest, during isometric plantarflexion, and for a recovery period. Only the healthy group displayed moderate correlation between PCr and perfusion. The diabetic patient group displayed attenuated recovery speed of PCr after exercise and no correlation between PCr and perfusion.

Sibaji Gaj¹, Brendan L. Eck¹, Dongxing Xie¹, Richard Lartey¹, Charlotte Lo¹, Mingrui Yang¹, Kunio Nakamura¹, Carl S. Winalski², Kurt Spindler³, and Xiaojuan Li^1
1Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States, ²Radiology, Cleveland Clinic, Cleveland, OH, United States, ³Orthopaedics, Cleveland Clinic, Cleveland, OH, United States

Quantitative assessment of thigh muscle morphology and fatty infiltration (FF%) in post-traumatic osteoarthritis is limited. In this work, we developed a deep learning based accurate segmentation method for muscles, bone and adipose tissue from thigh MRI and used these segmentation for automated quantification of FF and cross sectional area(CSA) of these tissues. 16 patients at 10 years after ACL reconstruction were studied. The proposed method showed significant improvement in segmentation metrics (Dice, Average surface distance (ASD)) and CSA compared with popular U-Net based deep learning models. For CSA and FF% quantification, automated methods had similar measurements compared with manual segmentation.

Stefan Zbyn^1,2, Abdul Wahed Kajabi^1,2, Ariel N. Rodriguez³, Gregory J. Metzger¹, Robert F. LaPrade³, and Jutta M. Ellermann^1,2
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, ²Department of Radiology, University of Minnesota, Minneapolis, MN, United States, ³Edina-Crosstown Surgery Center, Twin Cities Orthopedics, Minneapolis, MN, United States

Although T2 mapping allows noninvasive evaluation of meniscus degeneration, its application at 7T requires spin echo sequences with relatively long repetition times to meet the specific absorption rate (SAR) limits which can restrict the resolution of maps. This 7T study evaluates the potential of T2* mapping for the assessment of meniscal degeneration in six patients with arthroscopically verified posterior root tears of the medial meniscus and in healthy volunteers. Increased T2* in degenerated meniscus regions suggest T2* mapping is sensitive to meniscus degeneration. T2* mapping is a promising biomarker of early meniscal degeneration which is less SAR-demanding than T2 mapping.

Camille Noël^1,2, Constance Patricia Michel¹, Amira Trabelsi¹, Sébastien Vansteenkiste², Emmanuelle Salort-Campana³, Maëva Cotinat^2,4, Virginie De Bovis Milhe³, Laurent Bensoussan^2,4,5, Shahram Attarian³, and David Bendahan^1
1Aix Marseille University, Center for magnetic resonance in biology and medecine, Marseille, France, Metropolitan, ²Physical and Rehabilitation Medecine Departement, APHM, Marseille, France, Metropolitan, ³Reference Centre for Neuromuscular Diseases and ALS, APHM, Marseille, France, Metropolitan, ⁴CNRS, INT UMR 7289, Aix Marseille University, Marseille, France, Metropolitan, ⁵UGECAM Institut Universitaire de Réadaptation de Valmante Sud, Marseille, France, Metropolitan

Facioscapulohumeral dystrophy is the third genetic myopathy. Given that no therapeutic strategy has proved to be successful, rehabilitation has been considered as an interesting alternative. The aim of this study was to quantitatively evaluate the effects of a personalized rehabilitation strategy using MRI by tracking fat fraction (FF) and contractile volume (CV) over time. The lower limb was scanned before and after a rehabilitation program. FF and CV remained stable over the training period. Clinical parameters evolved positively. FF and CV were correlated to isokinetic strength thereby indicating that both metrics could be considered as biomarkers of the pathology progression.  

Xiao Liang¹, Nahla M H Elsaid², Li Jiang¹, Steve Roys¹, Maureen Stone³, Jerry L Prince⁴, Adam C Puche⁵, Rao P Gullapalli¹, and Jiachen Zhuo^1
1Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States, ²Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States, ³Department of Neural and Pain Sciences and Department of Orthodontics, University of Maryland School of Dentistry, Baltimore, MD, United States, ⁴Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States, ⁵Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States

Advanced dMRI techniques have been used to resolve the complex tongue muscle architecture. However, dMRI-derived tongue muscle architecture has not been validated with histology. In this study, we validated the dMRI-derived tongue muscle architecture with histology of a tongue specimen. dMRI was acquired for a post-mortem head and a healthy volunteer. dMRI-derived muscle fiber orientations, visualized as the tractogram, were compared against microscopic histology slices of the tongue specimen. Muscle fibers in the tractograms show good correspondence with those appearing in the histology images. The study demonstrates that dMRI can accurately reveal the complex muscle architecture of the human tongue.

Esther Rong¹, Jason Matakas¹, Steven Shamah¹, Jenna Le¹, Karen Sperling¹, Can Wu², and Qi Peng^1
1Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, United States, ²Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States

T1ρ and T2 contrasts provide complementary information on tissue properties. Therefore, their transient recovery after exercise to pre-exercise equilibria is potentially a functional biomarker for muscle disorder diagnosis and treatment evaluation. In this pilot study, we implemented and tested a high-temporal-resolution dynamic MRI sequence for simultaneous T1ρ and T2 mapping immediately after exercise. T1ρ and T2 contrasts presented unique transient recovery time courses in different skeletal muscles. Dynamic information derived from our imaging approach could potentially lead to greater sensitivity and specificity in evaluating muscle conditions compared with traditional methods with either T1ρ or T2 contrast alone.

Laura Secondulfo¹, Moritz Eggelbusch², Rob C.I. Wust ^2,3, Guido Weide³, Richard T. Jaspers³, Aart J. Nederveen⁴, Melissa Hooijmans¹, and Gustav Strijkers^1
1Biomedical Engineering and Physics, Amsterdam University Medical Center, Amsterdam, Netherlands, ²Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands, ³Department of Rehabilitation Medicine, VU University Medical Center Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands, ⁴4 Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands

Pennation angle is an important architecture parameter to understand muscle functioning. It is commonly measured using 2D ultrasound. However, it is difficult to infer 3D muscle architecture from 2D imaging. Therefore, we compare the pennation angle measurements obtained with 3D-DTI fiber-tractography and 3D-ultrasound (3D-US). We acquired data of the Vastus Lateralis muscle in 9 healthy subjects. The mean pennation angle with 3D-US was 18.9°± 5.9°, whereas we found 33.3°±6.7° (straight fiber approximation) and 34.5°±4.8°(curved fiber fit) for DTI fiber-tractography. These differences between 3D-US and DTI could be of technical or physiological origin.

Lumeng Cui¹, Emily J. McWalter^1,2, Gerald R. Moran³, and Niranjan Venugopal^4
1Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ²Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ³Research Collaboration Manager, Siemens Healthcare Limited, Oakville, ON, Canada, ⁴Department of Radiology, University of Manitoba, Winnipeg, MB, Canada

Ultrashort echo time (UTE) pulse sequences are used in synthetic computed tomography (sCT) generation for MR-based radiation treatment planning (RTP). This study used a novel Flexible UTE sequence (FUSE) for improving cortical bone imaging. Using a human skull, we applied the optimized UTE acquisition techniques and parameters and verified the improvements in overall image quality of cortical bone in comparison to a product UTE sequence. Also, we have shown the feasibility and potential of our FUSE sequence for generating the sCT data that is clinically equivalent to the traditional CT for RTP.

Allen A Champagne¹, Andrew McGuire², Kaden Shearer¹, Don Brien³, Paul A Martineau⁴, and Davide D Bardana^2
1School of Medicine, Queen's University, Kingston, ON, Canada, ²Department of Orthopedic Surgery, Queen's University, Kingston, ON, Canada, ³Center for Neuroscience Studies, Queen's University, Kingston, ON, Canada, ⁴Department of Orthopedic Surgery, McGill University, Montréal, QC, Canada

Diffusion tensor imaging (DTI) has emerged as biomarker to characterize the ligamentization process of the anterior cruciate ligament (ACL), following surgical reconstruction. One major limitation to this approach is the necessity for pre-injury baseline measurements to be used as a frame of reference, in order to inform clinical decision making with respect to recovery of the graft, and return-to-activity (RTA). Here, we explore the linear relationship for anisotropy between knees bilaterally, in healthy participants, to provide a methodological framework that allows for the clinical integration of DTI to monitor recovery of the tendon autograft, following surgical reconstruction, and inform RTA.

Joevin Sourdon^1,2, Tangi Roussel^1,2, Pierre Daude^1,2, Monique Bernard^1,2, Frank Kober^1,2, and Stanislas Rapacchi^1,2
1Aix-Marseille Université, CNRS, CRMBM, Marseille, France, ²AP-HM, Hôpital universitaire Timone, CEMEREM, Marseille, France

Vegetarian nutrition may contribute for metabolic differences that we proposed to explore non-invasively. 6 omnivores and 6 lacto-ovo-vegetarians underwent a 7T MRI exam including proton and phosphorus magnetic resonance spectroscopy to measure creatine (tCr), phosphocreatine (PCr) and triglyceride components in the soleus muscle. tCr and unsaturated fatty acids concentration were reduced in vegetarians but similar PCr/γ-ATP ratios were found. We show that vegetarian diet induces lower skeletal muscle creatine and different lipid profiles, which was not associated with altered bioenergetic reserve. This protocol opens new avenues to explore the impact of diet in skeletal muscle.

Yan Wen¹, Ek Tsoon Tan², Marc Lebel³, Suryanarayanan Kaushik³, Maggie Fung¹, and Darryl B. Sneag^2
1GE Healthcare, New York, NY, United States, ²Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States, ³GE Healthcare, Waukesha, WI, United States

To improve vascular suppression in 3D brachial plexus MR neurography (MRN) with FSE readouts, 3D directionally-selective crusher gradient technique was implemented. 3D Deep learning reconstruction (DLRecon 3D) with denoising and sharpening properties was applied to improve nerve conspicuity. Preliminary data showed that using both DLRecon 3D reconstruction and 3D crusher gradients resulted in improved image quality, image sharpness, and vascular suppression.