Muscle MRI features of the lower extremities in patients with limb girdle muscular dystrophy type R1 / 中华神经医学杂志

ABSTRACT

Objective:To investigate the muscle MRI features of the lower extremities and correlations between MRI fatty degeneration total scores and other clinical features in limb girdle muscular dystrophy type R1 (LGMDR1) patients.Methods:Clinical data of 8 patients with LGMDR1 diagnosed by genetic examination in Department of Neurology, He'nan Provincial People's Hospital&People's Hospital of Zhengzhou University from May 2016 to November 2021 were retrospectively analyzed. Disease severity was evaluated by Gardner-Medwin and Walton (GM-W) scale. Pathological staining results of the lower limb muscles were observed; the fatty infiltration and edema of the muscles were observed by MRI T1WI and short-tau inversion recovery (STIR) sequences. Lower limb muscles were scored using Mercuri's scale. Spearman rank correlation was used to analyze the correlations of MRI fatty degeneration total scores of the lower extremities with age, age of onset, disease duration, GM-W scale scores and creatinine kinase (CK) level.Results:Of the 8 patients with LGMDR1, 7 had decreased muscle strength in the proximal lower extremity, including 4 with decreased muscle strength in the distal lower extremity at the same time. Muscular dystrophy-like pathological changes of skeletal muscles were noted. All 8 LGMDR1 patients showed different degrees of fatty infiltration in the lower extremities: at the thigh level, the adductor magnus, biceps femoris long head, semimembranes, semitendinosus and adductor longus were the most severely fatty degeneration muscles (mean scores>4), with relatively sparing of the sartorius and rectus femoris; regarding the calves, gastrocnemius medial head was the mostly involved, followed by soleus, with relative sparing of the tibialis posterior and anterior compartment. Edema-like changes (mild) were observed in 7 patients; the muscles that most frequently and relatively severely displayed edema-like changes were the gastrocnemius lateral head and quadriceps. The fatty degeneration total scores of the lower extremities were positively correlated with GM-W scale scores ( r=0.872, P=0.005) and negatively correlated with CK level ( r=-0.929, P=0.001), but not significantly correlated with age, age of onset or disease duration ( r=0.635, P=0.091; r=0.571, P=0.139; r=0.551, P=0.157). Conclusion:The lower limb muscles with severe fatty infiltration are less prone to show edema-like changes; fatty degeneration can be used to evaluate LGMDR1 progress; involvement pattern of muscle MRI of the lower extremities is helpful in diagnosing and differentially diagnosing LGMDR1.