ABSTRACT
Objective To investigate muscle MRI characteristics of lower limbs in Chinese patients with dysferlinopathy. Methods Detailed clinical information of 42 patients with dysferlinopathy confirmed by Western blot or DYSF genetic test were studied retrospectively, including age, course, serum creatinine kinase (CK) and modified Gardner?Medwin and Walto score, and T1WI, STIR image. Each muscle was scored according to its fatty degeneration evaluated on T1WI (fat replacement score). The patients were divided into 3 groups:Miyoshi myopathy (MM), limb girdle muscle dystrophy 2B (LGMD 2B) and preclinical stage (asymptomatic hyperCKemia or exercise intolerance). The data including the scores of each muscle between MM and LGMD 2B were compared by ANOVA analysis and Chi square test. The relationship of fatty replacement score with course and GM?W score was analyzed by Spearman rank correlation analysis. Results Thirty nine patients underwent thigh MR scanning and 36 patients underwent leg MR scanning. At the thigh level, there is no specificity that the fatty replacement was found in both the anterior and posterior parts while the rectus femoris, sartorius and gracilis were rarely involved. At the leg level, the most severely involved muscle was the soleus, followed by gastrocnemius. It formed a sandwich?like pattern that the anterior part (anterior and posterior tibial muscle and peroneus longus muscle) and the posterior part (medial and lateral gastrocnemius) were less involved than the middle part (soleus). Of 42 patients, 14 cases were MM, and 24 were LGMD 2B. The fat replacement score of each muscle between two groups showed no significant differences (F=0.066 to 3.907,P all>0.05) except for the adductor muscle (F=5.239, P=0.028), semimembranosus (F=6.703, P=0.014) and semitendinosus (F=7.689, P=0.009). Of 4 pre?symptomatic cases, 3 showed edema of posterior part of leg on STIR, especially soleus. In all patients, the fat replacement score correlated positively with course (rs=0.732, P=0.000) and GM-W score (rs=0.485, P=0.001). Conclusions The MRI of Chinese patient with dysferlinopathy was characterized by the milder involvement of rectus femoris, sartorius and gracilis muscle in the thigh and a sandwich?like pattern in the leg, which is helpful for differential diagnosis of inflammatory Myopathy versus other types of muscular dystrophy.