目的 探讨进行性肌营养不良 (PMD)患儿的临床及MRI表现特征，评价 MRI对PMD的诊断价值。方法 回顾性分析 经临床和病理活检证实的33例PMD患儿的 临床表现、发病年龄、家族史、激酶、肌 电图、肌肉病理学特点及大腿肌肉的MRI 资料。结果 (1)男性多见，占91%，平均 年龄3岁10个月，2-8岁占82%，2例有明 确家族史(6%)。(2)所有患儿首次就诊均 有双侧肢体对称性肌无力表现，以双下 肢多见(76%)。(3)所有患儿CK值均明显升 高。(4)33例均行肌电图检查，表现为肌 源性损害。18例患儿行腓肠肌活检，病例 结果均符合进行性肌营养不良。(5)MRI主 要表现为2种信号改变：①T1WI和T2WI均 呈对称性高信号，STIR呈等信号，提示为 病变肌肉对称性脂肪替代，33例患儿股 四头肌、臀大肌均受累，其次为大收肌 (28例)、半膜肌(18例)、缝匠肌(16例)， 股薄肌(16例)、半腱肌(14例)、长收肌 (10例)。②T1WI呈等低信号，T2WI呈高信 号，STIR呈高信号，提示为炎性水肿，本 组资料22例PMD患儿部分受累肌群出现此 种信号改变，以股四头肌受累多见。33例 中11例合并肌肉萎缩，5例合并肌间隙脂 肪浸润；所有病例股骨及皮下脂肪信号未 见异常。结论 双下肢对称性肌无力是PMD 的主要临床表现。CK是诊断PMD的主要生 化指标。PMD肌电图表现为肌源性损害。 肌肉病例活检是确诊PMD的主要方法。儿 童PMD的MRI表现具有一定特征性，主要表 现为受累肌群的脂肪替代和炎性水肿，以 前者为主，MRI能够发现肌肉变性的程度 和范围，可为临床提供肌肉活检的优选部 位。

Objective To study the clinical and MRI features of progressive muscular dystrophy(PMD) in children and to access the diagnostic value of MRI in PMD. Methods Retrospective analysis was performed on the clinical data of 33 children with PMD, including clinical manifestations, age of onset,family history, creatase, electromyogram(EMG), pathological changes of muscles and the thigh muscle MRI findings. Results (1) 30(91%) cases were male.2 cases (6%) had a family history.(2) All cases presented symmetrical muscle weakness on the first consultation.25 cases(76%) appeared on bilateral lower extremities. (3) All cases had rised ceretine kinase(CK) levels. (4) EMG showed myogenic damage in all cases.Gastrocnemius muscle biopsy performed on 18 cases confirmed progressive muscular dystrophy.(5) Mainly two kinds of MRI signal features were found as follows: (1)The lesions carried hyperintense both on T1WI and T2WI, equisignal on STIR,showed symmetrical fat replacement for muscles in gluteus maximus and musculus quadriceps femoris of all cases,musculi adductor magnus of 28 cases, semitendinosus muscle of 18 cases, sartorius muscle and gracillis muscle of 16 cases, semitendinousus of 14 cases, musculi adductor magnus of 10 cases. (2)The lesions carried hypointense on T1WI and hyperintense on T2WI and STIR, showed muscle inflammation and edema in some involed muscles in 22 cases,with musculus quadriceps femoris as the most common.11 cases combined with muscular atrophy and 5 cases combined with spatium intermusculare fatty. No abnormality in bilateral femoral bone in all cases. Conclusion PMD showed a predominance of male. Symmetrical weakness of both lower extremities is the main manifestation of PMD. The MRI findings in PMD show characteristics in children, it displays two kinds of abnormal signals which represent fat replacement and inflammatory edema lesion. MRI can provide the degree and extent of the muscle degeneration, it can help to decide the accurate localizations for biopsy.