Xeni Deligianni^1,2, Francesco Santini^1,2, Matteo Paoletti³, Francesca Solazzo³, Niels Bergsland^4,5, Giovanni Savini³, Arianna Faggioli³, Giancarlo Germani³, Mauro Monforte⁶, Giorgio Tasca⁶, Enzo Ricci⁶, and Anna Pichiecchio^3,7
1Department of Radiology/ Division of Radiological Physics, University Hospital of Basel, Basel, Switzerland, ²Biomedical Engineering, University of Basel, Allschwil, Switzerland, ³Advanced Imaging and Radiomics Center, Neuroradiology Department, IRCCS Mondino Foundation, Pavia, Italy, ⁴Buffalo Neuroimaging Analysis Center, Department of Neurology, Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, United States, ⁵IRCCS, Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy, ⁶Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy, ⁷Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy

Quantitative muscle MRI (T2&fat mapping) is progressively more used to assess disease involvement in muscle disorders, but in a static way, with dynamic assessment usually performed by clinical and instrumental examinations. To characterize muscle deformation we applied dynamic MRI synchronized with neuromuscular electrical stimulation evaluating the quadriceps muscles in 34 ambulatory subjects affected by facioscapulohumeral muscular dystrophy (FSHD) and ten healthy controls, longitudinally. Maximum values and rates of the strain differed between the two groups. Our results suggest that the evaluation of muscle ability to contract could be potentially used to monitor the evolution of muscle involvement in FSHD.

Xingyu Zhou^1,2, Melissa T. Hooijmans^1,3, Crystal L. Coolbaugh¹, Mark K. George¹, and Bruce M. Damon^1,2,4,5
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, ²Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ³Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Center, Amsterdam, Netherlands, ⁴Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, ⁵Department of Molecular Physiology & Biophysics, Vanderbilt University Medical Center, Nashville, TN, United States

Diffusion-tensor MRI (DTMRI) fiber tractography is a useful tool for reconstructing the structure of white matter tracts, nerves, and muscles. Eddy current correction is recognized as an important step in analysis of neuronal DTMRI data, while its effect on muscle DTMRI analysis has not been studied systematically. In this work we describe a preliminary comparison of muscle diffusion tensor imaging results with and without including eddy current correction in the pre-processing steps, including the morphological mismatch with anatomical image, the estimation of eigenvalues and fractional anisotropy, and the distribution of the first eigenvector within the selected muscle.

Kihwan Kim¹, Yuning Gu¹, Yuran Zhu¹, Yudu Li^2,3, Sherry Huang¹, Zhi-Pei Liang ^2,3, and Xin Yu^1,4
1Biomedical Engineering, Case Western Reserve University, cleveland, OH, United States, ²Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ³Beckman Institute for advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ⁴Case Center for Imaging Research, Case Western Reserve University, cleveland, OH, United States

This study investigated the creatine kinase activity and the effects of repeated muscle contraction on muscle metabolism in mdx mice, a mouse model for Duchenne Muscular Dystrophy (DMD). Using phosphorous-31 (³¹P) magnetic resonance fingerprinting and dynamic ³¹P magnetic resonance spectroscopy, we observed a significant decrease in creatine kinase (CK) reaction rate in mdx mice compared to control mice.  Decrease in phosphocreatine (PCr) recovery rate after its depletion by stimulation-induced muscle contraction was also observed in mdx mice. These findings suggest altered mitochondrial function in mdx mice.

Natenael B Semmineh¹, Sudarshan Ragunathan², Laura C Bell², and C Chad Quarles ^2
1Imaging Research, Barrow Neurological Institute rrow Neurological Institute, Phoenix, AZ, United States, ²Imaging Research, Barrow Neurological Institute, Phoenix, AZ, United States

 The relaxivity contrast imaging parameter, TRATE (tissue transverse relaxivity at tracer equilibrium), has been shown to decrease during ALS induced myofiber degradation, due to T1 and T2* effects that occur when the contrast agent distributes around myofibers. The goal of this study is to expand a validated computational method to investigate the biophysical basis of TRATE in muscles of ALS patients and to optimize RCI acquisition parameters.

Amy R McDowell¹, Matthew T Lee², Kiran K Seunarine², and Chris A Clark^2
1Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom, ²GOS UCL Institute of Child Health, London, United Kingdom

An examination of the effect of moderate exercise on diffusion indices in skeletal muscle in volunteers in order to quantify the effect of the exercise, and define when diffusion indices returned to baseline rest values. We found that there was no significant difference between pre- and post-exercise MD or FA. We believe that moderate exercise will have no evident effect on diffusion indices, and no period of rest pre-scan is required.

Mengyue Wang¹, Weiqiang Dou², Yu Zheng¹, Yin Shi¹, and Yuefen Zou^1
1The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²GE Healthcare, MR Research China, Beijing, China

   Muscle asymmetry and fatty infiltration resulting from lumbosarcal nerve root compression are associated with movement ability directly. However, the specific rule remains unclear. In this study, we used three dimensional fast imaging empolying steady-state acquisition with phase cycling(3D-FIESTA-C) and iterative decomposition of water and fat with echo asymmetry and least-squares estimation intelligent quantification (IDEAL-IQ) technique to evaluate the changes quantitatively. We found muscle changes were side- and level-specific, affected by several other factors. Muscle content is suggested as a good parameter for clinical evaluation.

Alfredo Liubomir Lopez Kolkovsky^1,2, Beatrice Matot^1,2, Eric Giacomini¹, Martin Meyerspeer³, Benjamin Marty^1,2, and Harmen Reyngoudt^1,2
1NMR Laboratory, Institute of Myology, Paris, France, ²NMR Laboratory, CEA\DRF\IBFJ\MIRCen, Paris, France, ³High Field MR Center, CMPBME, Medical University of Vienna, Vienna, Austria

We extended an interleaved ¹H/³¹P multi-voxel sequence for simultaneous pH monitoring based on carnosine (pH_1H, PRESS) and Pi (pH_31P, semi-LASER) with a co-localized dynamic water reference (PRESS). Simultaneous pH evaluations were done at 3 T in the soleus and gastrocnemius muscles during a straight-leg plantar flexion paradigm. A pH_1H bias of ~0.05 units was removed by using the dynamic water reference. pH_1H and pH_31P time courses (1-minute temporal resolution) were comparable. Pi and Carnosine (C2-H) resonances broadened during exercise in the gastrocnemius. This method opens the way for new applications in functional studies targeting individual muscles at 3 T.

Weihong Guo¹, Michael Judkovich¹, Richard Lartey², Dongxing Xie², Mingrui Yang², and Xiaojuan Li^2
1Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, OH, United States, ²Biomedical Engineering, Program of Advanced Musculoskeletal Imaging (PAMI), Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States

Thigh muscle morphology and composition quantified from MR images are potential imaging biomarkers for diseases such as osteoarthritis and sarcopenia. MR thigh muscle segmentation is an important step in quantifying both muscle morphology and composition. Unfortunately, the thigh muscle groups are tightly bundled together, making them very hard to segment due to a lack of clear boundaries between different muscles.  We proposed a novel geometric flow based semi-automatic scheme to effectively segment them. We combined reproducible kernel Hilbert space edge descriptor and geodesic distance maps from a set of markers and anti-markers to define the force for the geometric flow.

Donnie Cameron^1,2, Jedrzej Burakiewicz¹, Nienke M. van de Velde³, Celine Baligand¹, Thom T.J. Veeger¹, Melissa T. Hooijmans⁴, Jan J.G.M. Verschuuren³, Erik H. Niks³, and Hermien Kan^1
1C.J. Gorter Centre for High Field MRI, Department of Radiology, Leiden University Medical Centre, Leiden, Netherlands, ²Norwich Medical School, University of East Anglia, Norwich, United Kingdom, ³Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands, ⁴Biomedical Engineering and Physics, Amsterdam University Medical Centre, Amsterdam, Netherlands

Becker muscular dystrophy (BMD) is characterised by progressive muscle damage and weakness. Diffusion tensor imaging (DTI) represents a promising candidate for studying BMD; the random permeable barrier model (RPBM), in particular, gives estimates of muscle fibre diameters and membrane permeabilities. Here we study DTI and RPBM metrics in BMD patients and controls. Spin-echo and stimulated-echo DTI data were acquired in the lower leg and RPBM metrics calculated. DTI metrics showed time-dependence and intramuscular differences, but no inter-group differences. RPBM analysis, however, successfully showed differences between BMD patients and controls, with fibre diameters being larger and more variable in patients.

Francesco Santini^1,2, Xeni Deligianni^1,2, Matteo Paoletti³, Francesca Solazzo³, Matthias Weigel^1,4,5, Paulo Loureiro De Sousa⁶, Oliver Bieri^1,2, Mauro Monforte⁷, Enzo Ricci^7,8, Giorgio Tasca⁷, Anna Pichiecchio^3,9, and Niels Bergsland^10,11
1Radiological Physics, Department of Radiology, University Hospital of Basel, Basel, Switzerland, ²Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland, ³Neurological Institute Foundation Casimiro Mondino (IRCCS), Pavia, Italy, ⁴Translational Imaging in Neurology, Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland, ⁵Department of Neurology, University Hospital of Basel, Basel, Switzerland, ⁶UMR7357 Laboratoire des sciences de l'Ingénieur, de l'Informatique et de l'Imagerie (ICube), Strasbourg, France, ⁷Institute of Neurology, A. Gemelli University Hospital Foundation, Catholic University of the Sacred Heart, Rome, Italy, ⁸Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy, ⁹Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy, ¹⁰Western New York Stem Cell Culture and Analysis Center, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, NY, United States, ¹¹Fondazione Don Carlo Gnocchi Onlus (IRCCS), Milan, Italy

The measurement of the T2 of the water component is an important marker of neuromuscular diseases. Strategies exist to estimate it from conventional multi-echo spin-echo acquisitions, taking into account fat infiltration and B1 inhomogeneity. In this work, we present an open software that is able to efficiently perform this kind of fitting, and additionally to incorporate the information from an external fat fraction acquisition, for increased accuracy and reduced scan time.

Melissa T. Hooijmans^1,2, Crystal L. Coolbaugh³, Xingyu Zhou^2,4, Mark K. George², and Bruce M. Damon^4,5,6
1Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam UMC, Location AMC, Amsterdam, Netherlands, ²Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, ³Vanderbilt University Institute of Imaging Sciences, Nashville, TN, United States, ⁴Department of Biomedical Engineering, Vanderbilt University Medical Center, Nashville, TN, United States, ⁵Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, ⁶Department of Molecular Physiology & Biophysics, Vanderbilt University Medical Center, Nashville, TN, United States

SPAMM, combined with HARP, is primarily used for strain quantification in the myocardium; but applications in other soft tissues, including skeletal muscle, are increasing. HARP suffers from artifacts due to usage of inappropriate filters and should therefore be optimized especially for skeletal muscle. We simulated strains ranging from -0.156 to +0.156 (decimal strain) in dynamically acquired line- and grid-tagged SPAMM images, and optimized elliptical filter parameters were determined for skeletal muscle. With this filter, differences between the measured strain and absolute strain were small for the low strain values and increased with the actual strain values and number of dynamics.

Claudia Weidensteiner^1,2, Xeni Deligianni^1,2, Tanja Haas¹, Philipp Madoerin¹, Oliver Bieri^1,2, Meritxell Garcia³, Jacqueline Romkes⁴, Erich Rutz⁵, Francesco Santini^1,2, and Reinald Brunner^6
1Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland, ²Department of Biomedical Engineering, University of Basel, Basel, Switzerland, ³Department of Radiology, Division of Neuroradiology, University Hospital Basel, Basel, Switzerland, ⁴Laboratory for Movement Analysis, University Children's Hospital Basel, Basel, Switzerland, ⁵Hugh Williamson Gait Laboratory, The Royal Children's Hospital Melbourne, Parkville, Australia, ⁶Department of Orthopedic Surgery, University Children's Hospital Basel, Basel, Switzerland

Aim of this study is to investigate the feasibility of phase contrast imaging at 3T for assessment of muscle function in children with cerebral palsy. Time-resolved cine phase contrast MRI was synchronized with (a) electrical muscle stimulation (EMS) of the calf muscle (b) voluntary plantarflexion following visual instructions.  The achieved force was higher for the voluntary task, but its periodicity was lower compared to the stimulated contraction. Therefore, it was not possible to resolve two distinct velocity peaks for voluntary contraction and release, but it was during EMS, in case the tolerated current was high enough to evoke sufficient contraction.

Amy R. McDowell¹, Stephen J. Wastling^1,2, Lara Cristiano³, Jasper M. Morrow¹, Matthew R.B. Evans⁴, Christopher D.J. Sinclair¹, Pedro M. Machado¹, Michael Hanna¹, Mary M. Reilly¹, Tarek Yousry¹, and John S. Thornton^1
1MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom, ²Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom, ³Department of Pediatric Neurology and Radiology, Fondazione Policlinico Universitario, Rome, Italy, ⁴St Thomas Hospital, London, United Kingdom

Muscle T₂ and fat-fraction are two promising metrics for sensitive measures of early disease-related changes in muscle for use in clinical trials. However, fat has a longer T₂ than water in muscle and masks underlying increases in water T₂ due to muscle oedema. The IDEAL-CPMG sequence with appropriate image-data processing produces a T₂-water map uncontaminated by the fat signal. This sequence was acquired in healthy volunteers and two different muscular dystrophy disease types. It was found that elevated T₂-water may be a predictor of later progression to fatty-atrophy in muscle, supporting the value of future longitudinal studies to test this.

Neil Wilson¹, Mark A Elliott², Dushyant Kumar², and Ravinder Reddy^2
1Siemens Medical Solutions USA Inc, Malvern, PA, United States, ²CMROI, University of Pennsylvania, Philadelphia, PA, United States

Dynamic CrCEST allows for high resolution mapping of the creatine kinase reaction recovery kinetics following exercise. However, voxel averaging over large ROIs is usually done to get reliable fits because of high variation due to limited SNR. Here, we show that improved denoising utilizing low rank tensor approximations that exploit the full dimensionality of the scans allows for reliable fits over smaller volumes or even single voxels, making muscle response heterogeneity measurable.

Rajakumar Nagarajan¹ and Gwenael Layec^2
1Human Magnetic Resonance Center, Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, United States, ²Kinesiology, University of Massachusetts Amherst, Amherst, MA, United States

In this study, we demonstrate the feasibility and sensitivity of ³¹P two-dimensional CSI sequence for the detection of alkaline Pi in the soleus, tibialis anterior, and gastrocnemius muscles in six healthy volunteers in rest. The major finding of the current study was the consistent detection of an alkaline Pi from the cytosolic Pi signal in the volume localized ³¹P MRS from the resting muscle in healthy human subjects at 3T using decoupling technique. This study provides the proof of concept for a non-invasive and localized method to determine the alkaline Pi, a potential index of mitochondrial density at rest.

Matthew Birkbeck^1,2,3, Linda Heskamp¹, Ian Schofield¹, Roger Whittaker¹, and Andrew Blamire^1
1Translational and Clinical Research Unit, Newcastle University, Newcastle upon Tyne, United Kingdom, ²Newcastle Biomedical Research Centre, Newcastle Biomedical Research Centre, Newcastle upon Tyne, United Kingdom, ³Northern Medical Physics and Clinical Engineering, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, United Kingdom

Motor unit (MU) magnetic resonance imaging (MUMRI) is a non-invasive technique which detects muscle fibre micro-contraction and is based on diffusion weighted MRI. To date MUMRI has been applied in conjunction with in scanner electrical stimulation to study MU activity in the lower leg. Here we present the first use of MUMRI in the upper limbs to study single human MUs.  The acquired images show low levels of distortion and good fat suppression, allowing single human MU sizes and shapes to be determined. This is of interest in neuromuscular diseases as it is a non-invasive way to study MU morphology.

Hon J Yu¹, Saya Horiuchi^1,2, Toshimi Tando¹, Vincent J Caiozzo³, Virginia E Kimonis⁴, and Hiroshi Yoshioka^1
1Radiological Sciences, University of California, Irvine, Orange, CA, United States, ²Radiology, St. Luke's International Hospital, Tokyo, Japan, ³Department of Orthopaedics, Physiology & Biophysics, University of California, Irvine, Irvine, CA, United States, ⁴Division of Genetic and Genomic Medicine, Department of Pediatrics, University of California, Irvine, Irvine, CA, United States

This study evaluates texture features to demonstrate their relationship with muscle classification based on a 5-grade scale and their value as classifier when trained in supervised machine-learning framework. The results suggest the texture features capture various image characteristics that are likely utilized during manual muscle classification by human being and can correctly predict with up to 81% accuracy when properly trained in supervised machine-learning setting. A further study with bigger data size would be necessary to fully examine such classification model and also to look into the possibility of selecting subset of features to make such an approach more practical.

Sarah Catherine Wayte¹, Alexander Dallaway², Andrew David Weedall¹, John Hattersley³, and Adrian John Wilson^3,4
1Radiology Physics, Department of Clinical Physics and Bioengineering, University Hospital, Coventry, United Kingdom, ²Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom, ³Coventry NIHR CRF, Human Metabolic Research Unit, University Hospital, Coventry, United Kingdom, ⁴Department of Physics, University of Warwick, Coventry, United Kingdom

¹H MRS was used to investigate relative concentrations of methylene intracellular lipids [IMCL_CH2]_R and creatine [Cr]_R in the psoas of groups of younger (19-30yrs) and older (61-81yrs) fit male volunteers.  No difference was found between groups for either metabolite (p>0.05). However, the median value for [Cr]_R in the older group (median;Q1-Q3=1.02;0.55-1.29%) was much higher than in the younger group (0.57;0.50-0.60%) suggesting [Cr]_R could partially explain reduction in muscle strength with age being greater than predicted by loss of muscle mass. There was no correlation between metabolite concentrations (r²=0.21) so [Cr]_R may possibly be a marker for age-related changes in muscle.

Arthur Jourdan¹, Arnaud Le Troter², Pierre Daude², Stanislas Rapacchi², Catherine Masson¹, Thierry Bege^1,3, and David Bendahan^2
1Aix-Marseille Univ, Univ Gustave Eiffel, IFSTTAR, LBA, Marseille, France, ²Aix Marseille Univ, CNRS, CRMBM, Marseille, France, ³Department of General Surgery, Aix Marseille Univ, North Hospital, APHM, Marseille, France

A novel semi-automatic post-processing method dedicated to real-time dynamic MRI aiming at a fast and reliable quantification of abdominal wall muscles deformations. The described method combines a highly accurate supervised 2D+t segmentation procedure of the abdominal wall muscles (mean Dice similarity coefficient of 0.95 ± 0.03), the quantification of muscles deformations based on masks registration and the mapping of deformations within muscle compartments leveraging a dedicated parcellation. The present genuine method provides a quantitative analytical frame that could be used in further studies for a better understanding of abdominal wall deformations in physiological and pathological situations.

Cyril Tous, PhD¹, Alexandre Jodoin, MD², Detlev Grabs, MD, PhD³, Elijah Van Houten, PhD⁴, and Nathalie J Bureau, MD MSc FRCP(C)^1,2
1Radiology, Centre de recherche du Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada, ²Radiology, Centre hospitalier de l’Université de Montréal, Montréal, QC, Canada, ³Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada, ⁴Mechanical Engineering, Université de Sherbrooke, Sherbrooke, QC, Canada

Surgical planning of rotator cuff tears does not benefit from quantitative measurement of muscles stiffness and microstructure leading to retears in the following years. Since stiffness is dependent on anisotropy, Diffusion Tensor Imaging can simplify the inversion algorithm of Magnetic resonance elastography. Repeatability of DTI metrics from three scans in six shoulders of six asymptomatic volunteers was achieved (coefficient of variance <10%) for the fractional anisotropy, mean diffusivity, mode and eigenvalues. Clear convergence of myocytes to the tendons was observed with tractography in the supraspinatus as known in dissection. This MRI protocol is promising for developing biomarkers for surgical planning.