Jasper M. Morrow1, Christopher DJ Sinclair1, 2, Arne Fischmann2, Xavier Golay2, Tarek A. Yousry1, 2, Mary M. Reilly1, Michael G. Hanna1, John S. Thornton1, 2
1MRC Centre for Neuromuscular Diseases, Dept. of Molecular Neurosciences, UCL Institute of Neurology, University College London, London, United Kingdom; 2Academic Neuroradiological Unit, Dept of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom
We measured lower-limb thigh and calf muscle fat-fractions by 3-point Dixon MRI in 20 Charcot-Marie-Tooth disease 1A (CMT1A) patients, 20 patients with inclusion body myositis (IBM) and 28 healthy controls. Mean %fat-fractions were increased in both patient groups relative to controls for all calf muscles (p<0.01) and in IBM patients for all thigh muscles (p<0.001). Relevant remaining cross-sectional muscle area, a composite measure accounting for both muscle atrophy and fat replacement, was highly correlated (R=0.57-0.90, p <0.001) with accurate functional measures of knee and ankle strength. Dixon lower-limb muscle-fat assessment shows promise as a trial outcome measure in neuromuscular diseases.