EP.36PATCHS MRI score correlates with clinical severity in facioscapulohumeral muscular dystrophy

Abstract

To find the involvement pattern of skeletal muscle in FSHD patients and its correlation with clinical evaluations. PATCHS MRI scans of multi-section muscles consist of bilateral 6 muscle groups including scapular girdle, humeral, pelvic girdle, thigh, calf and axial muscles, with a total of 78 muscles. PATCHS MRI scans in 30 Chinese FSHD1 patients were semi-quantitively assessed for fat infiltration and were correlated to multiple clinical outcome measures. Cluster analysis was conducted to identify the different involvement pattern of muscles. In scapular girdle and humeral muscle, the most frequently and severely involved muscles were the trapezius, serratus anterior, rhomboideus and latissimus dorsi. And in pelvic girdle and leg muscles, they were semimembranosus, biceps femoris, gluteus minimus and semitendinosus. The fat infiltration score of total skeletal muscles correlated highly with the motor function measure, FSHD clinical score, Ricci score, 6-minute walking test and manual muscle testing (correlation coefficients -0.8767, 0.7768, 0.7705, -0.7077, 0.6973, respectively). And the correlation was stronger in PATCHS MRI than in MRI of legs. Cluster analysis indicated two distinctive patterns of muscle involvement, suggesting a group of untypical FSHD patients with early and more severely involved pelvic girdle and leg muscles. We showed a strong correlation between the fat infiltration score of PATCHS MRI and clinical outcome measures. PATCHS MRI scans unfolded a better performance in capturing the disease severity and motor functioning comparing with MRI of legs. We identified a group of untypical FSHD patients with early and more severely involved pelvic girdle and leg muscles, indicating the wide spectrum of phenotype in FSHD.