目的 探讨3.0T MRI在多发性肌 炎(PM)和皮肌炎(DM)诊断中的价值。方 法 回顾性分析2015年1月至2017年7月我 院收治的17例PM患者和22例DM患者临床 资料，所有患者均进行3.0T MRI检查，分 析其图像，并将其结果与血清肌酶各指 标检查结果和肌肉活检结果进行比较。 结果 共39例PM和DM患者中，36例出现肌 肉炎性水肿，11例表现为肌筋膜增厚(肌 筋膜炎)，18例出现皮下软组织水肿， 8例出现肌肉萎缩伴脂肪浸润。肌筋膜 炎、皮下软组织水肿者均出现肌肉炎性 水肿。肌肉炎性水肿病变区T1WI呈等信 号，T2WI呈高信号，STIR呈高信号；肌 筋膜炎T1WI呈等信号，T2WI肌间隙呈高 信号，STIR肌间隙呈高信号；皮下软组 织水肿T1WI上皮下脂肪呈低信号，T2WI 呈稍高信号，STIR呈高信号；肌肉萎缩 伴脂肪浸润病变区T1WI呈短信号，T2WI 呈长信号。3.0T MRI扫描结果与血清肌 酶各指标检查结果相比，差异具有统计 学意义(P<0.05)。3.0T MRI扫描结果与 肌肉活检结果相比，差异无统计学意义 (P>0.05)。结论 3.0T MRI在PM和DM诊断 中具有重要应用价值，肌肉炎性水肿是 PM和DM患者在3.0T MRI检查中最常见表 现。

Objective To explore the value of 3.0T MRI in the diagnosis of polymyositis (PM) and dermatomyositis (DM). Methods The clinical data of 17 PM cases and 22 DM cases admitted to our hospital from January 2015 to July 2017 were analyzed retrospectively. All patients were given 3.0T MRI examination, and their images were analyzed, and the results were compared with results of serum muscle enzymes markers and muscle biopsy. Results Among 39 PM and DM patients, there were 36 cases of muscular inflammatory edema, 11 cases of myofascial thickening (myofascitis), 18 cases of subcutaneous soft tissue edema and 8 cases of muscular atrophy and fat infiltration. Patients with myofasciitis and subcutaneous soft tissue edema tended to have muscular inflammatory edema. In inflammatory edema area of muscle, there was equal signal on T1WI, high signal on T2WI and high signal on STIR. In the intermuscular space of myofascialitis, there was equal signal on T1WI, high signal on T2WI and high signal on STIR. In the subepithelial fat of subcutaneous soft tissue edema, there was low signal on T1WI showed, slightly high signal on T2WI and high signal on STIR. In the area of muscle atrophy and fatty infiltration, there was short signal on T1WI and long signal on T2WI. There were significant differences between the results of 3.0T MRI scan and the results of serum muscle enzymes markers (P<0.05). There was no significant difference between the 3.0T MRI scan results and muscle biopsy results (P>0.05). Conclusion 3.0T MRI has important application value in the diagnosis of PM and DM. Muscular edema is the most common manifestation of 3.0T MRI in PM and DM patients.