肢带型肌营养不良R1型下肢肌肉MRI特点分析

Muscle MRI features of the lower extremities in patients with limb girdle muscular dystrophy type R1

目的探讨肢带型肌营养不良R1型(LGMDR1)患者下肢肌肉MRI特点及MRI脂肪化总评分与其他临床特征的相关性。方法回顾性分析河南省人民医院暨郑州大学人民医院神经内科自2016年5月至2021年11月收治的经基因检测确诊为LGMDR1的8例患者资料。应用Gardner-Medwin和Walton(GM-W)评分评估肌无力严重程度,观察肌肉病理染色结果,通过MRI T1WI序列、短时间反转恢复序列(STIR)观察肌肉脂肪化情况及水肿程度,并采用Mercuri’s评分对下肢肌肉进行评分;最后采用Spearman相关分析检验下肢肌群脂肪化总评分与年龄、起病年龄、病程、GM-W评分及肌酸激酶(CK)水平的相关性。结果8例LGMDR1患者中7例出现下肢近端肌力下降,其中4例伴下肢远端肌力下降;骨骼肌病理均呈肌营养不良样病理改变。所有患者下肢肌肉均出现不同程度脂肪化,在大腿层面脂肪化最重的是大收肌、股二头肌长头、半膜肌、半腱肌和长收肌(平均分≥4分),缝匠肌和股直肌相对保留;小腿层面脂肪化最重的是腓肠肌内头,其次是比目鱼肌,胫骨后肌和前部肌群相对保留。7例患者伴有肌肉水肿,水肿程度普遍较轻,较易出现水肿及水肿程度相对较高的肌肉为小腿腓肠肌外头及大腿股四头肌。LGMDR1下肢肌群脂肪化总评分与GM-W评分呈正相关关系(r=0.872,P=0.005),与CK水平呈负相关关系(r=-0.929,P=0.001),与年龄、发病年龄及病程均无相关性(r=0.635,P=0.091;r=0.571,P=0.139;r=0.551,P=0.157)。结论LGMDR1患者下肢重度脂肪化肌肉不易出现水肿,肌肉脂肪化程度可用于评估疾病进展。下肢肌肉MRI受累模式有助于诊断与鉴别诊断LGMDR1。

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.