Division of Rheumatology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
Department of Radiology, The Jikei University School of Medicine, Tokyo, Japan.
RMD Open. 2019 Mar 28;5(1):e000850. doi: 10.1136/rmdopen-2018-000850. eCollection 2019.
To define the characteristic findings on MRI of skeletal muscles in patients with dermatomyositis (DM) relative to those in patients with other idiopathic inflammatory myopathies (IIMs) and to assess their diagnostic performance in DM.
Thirty-six patients with DM, 17 patients with amyopathic DM, 19 patients with polymyositis and 16 patients with non-IIM classified by the 2017 European League Against Rheumatism/American College of Rheumatology criteria were included in this study. The following MRI findings (short-tau inversion recovery [STIR] and gadolinium-enhanced fat-suppressed T1-weighted imaging [Gd-T1WI]) for proximal limb muscles were compared between the disease groups and between myositis-specific autoantibodies/myositis-associated autoantibodies (MSAs/MAAs)-positive and MSAs/MAAs-negative groups: structures with high signal intensity (HSI) (subcutaneous, fascia, muscle); distributions of HSI areas in muscle (diffuse, patchy, peripheral) and patterns of HSI in muscle (honeycomb, foggy, strong HSI). Univariate, multivariate and receiver-operating characteristic [ROC] analyses were performed to assess the diagnostic performance of MRI in DM.
The characteristic MRI findings in patients with DM were subcutaneous HSI, fascial HSI, peripheral distribution and honeycomb pattern. The MRI findings in the MSAs/MAAs-positive group included more frequent fascial HSI but less frequent foggy pattern compared with the MSAs/MAAs-negative group. Likelihood of DM score ≥ 3 (obtained by counting the number of characteristic MRI findings in patients with DM) showed good diagnostic performance in DM (STIR: sensitivity 72.2%, specificity 88.5%, area under ROC curve [AUC] 84.9%; Gd-T1WI: sensitivity 81.2%, specificity 91.5%, AUC 89.9%).
The characteristic MRI findings of skeletal muscles can predict patients with DM as well as patients with MSAs/MAAs.
定义皮肌炎（DM）患者的骨骼肌 MRI 特征表现，并与其他特发性炎性肌病（IIM）患者进行比较，评估其在 DM 中的诊断性能。
本研究纳入 36 例 DM 患者、17 例无肌病型 DM（amyopathic DM）患者、19 例多发性肌炎患者和 16 例按 2017 年欧洲抗风湿病联盟/美国风湿病学会标准分类的非 IIM 患者。比较各组间及肌炎特异性自身抗体/肌炎相关自身抗体（MSAs/MAAs）阳性组与 MSAs/MAAs 阴性组间近端肢体肌肉的 MRI 表现（短 tau 反转恢复[STIR]和钆增强脂肪抑制 T1 加权成像[Gd-T1WI]）：高信号强度（HSI）结构（皮下、筋膜、肌肉）；肌肉内 HSI 区域分布（弥漫性、斑片状、外周性）和肌肉内 HSI 模式（蜂窝状、雾状、强 HSI）。采用单变量、多变量和受试者工作特征[ROC]分析评估 MRI 在 DM 中的诊断性能。
DM 患者的特征性 MRI 表现为皮下 HSI、筋膜 HSI、外周分布和蜂窝状模式。MSAs/MAAs 阳性组的 MRI 表现为更频繁的筋膜 HSI，但与 MSAs/MAAs 阴性组相比，更少见雾状模式。DM 评分≥3（通过计数 DM 患者的特征性 MRI 表现数获得）的可能性显示出对 DM 的良好诊断性能（STIR：敏感性 72.2%，特异性 88.5%，ROC 曲线下面积[AUC]84.9%；Gd-T1WI：敏感性 81.2%，特异性 91.5%，AUC 89.9%）。
骨骼肌的特征性 MRI 表现可以预测 DM 患者以及 MSAs/MAAs 阳性患者。
