目的 分析多发性肌炎(PM)/皮 肌炎(DM)患者肌肉MRI影像表现特点并 探讨其临床使用价值。方法 回顾性分 析90例PM/DM患者临床资料和肌肉MRI图 像，分析其自旋回波序列(T1WI)、快速 自旋回波序列(T2WI)、短时翻转恢复序 列(STIR)成像特点，并结合血清肌酸激 酶(CK)、肌电图(EMG)、穿刺活检检查结 果和临床诊断结果探讨MRI检查优劣势 和临床应用价值。结果 MRI检查灵敏度 92.22%，明显高于CK、EMG和病理活检 (78.89%、71.11%和82.22%，P<0.05)； PM/DM肌肉炎性水肿MRI表现为T1WI低信 号或等信号，T2WI和STIR呈高亮信号； PM/DM肌筋膜炎MRI表现为T1WI低信号或 等信号，T2WI和STIR呈带状高亮信号； PM/DM皮下组织水肿MRI表现为T1WI低信 号或等信号，T2WI和STIR呈异常高信 号；PM/DM肌肉萎缩伴脂肪浸润T1WI、 T2WI和STIR示正常信号肌群内出现点状 或小片状高信号病灶。结论 PM/DM患者应 用MRI检查，灵敏度和特异度均较高，其 中T1WI信号可清晰显示脂肪浸润病变， T2WI和STIR成像则对炎性水肿、肌肉萎 缩及肌筋膜炎有较高鉴别价值，可用于 临床早期诊断。

Objective To analyze the muscular MRI imaging features of patients with polymyositis (PM)/dermatomyositis (DM) and explore the clinical application values. Methods The clinical data and MRI images of 90 PM/DM patients were analyzed retrospectively. The imaging features of the spin-echo T1-weightedimages sequence (T1WI), the fast spin-echo T2-weighted images sequence(T2WI) and the shorttime reversal recovery sequence (STIR) were analyzed. Serum creatine kinase(CK), electromyography (EMG), biopsy results and clinical diagnostic results were combined to discuss the advantages and disadvantages of MRI and the clinical application values. Results The sensitivity of MRI was significantly higher than that of CK detection, EMG examination and pathological biopsy(92.22% vs 78.89%, 71.11% and 82.22%,P<0.05). The MRI of PM/DM muscle inflammatory edema showed low signal or equal signal in T1WI and high signal in T2WI and STIR. The MRI of PM/DM myofasciitis showed low signal or equal signal in T1WI, and banded highlight signal in T2WI and STIR. The MRI of PM/DM subcutaneous tissue edema showed low signal or equal signal in T1WI and abnormal high signal in T2WI and STIR. The T1WI, T2WI and STIR of PM/ DM muscle atrophy with fatty infiltration showed spot or flake-like high signal lesions in normal signal muscle group. Conclusion MRI for PM/DM patients can have high sensitivity and specificity, and T1WI signal can clearly show fatty infiltration lesions, and T2WI and STIR imaging have high differential values of inflammatory edema, muscle atrophy and myofascitis, and are suitable to early clinical diagnosis.