免疫介导性坏死性肌病的肌肉损害特点

目的:借助肌肉磁共振成像MRI技术分析不同序列下坏死性肌病患者的肌肉损害参数的改变,以及肌肉损害的分布情况。方法:确诊为SRP抗体阳性的坏死性肌病16例,多发性肌炎患者14例,同期年龄性别相似、既往无基础疾病的健康人群18例纳入研究。对所有的入选患者行双侧大腿肌肉各肌群的MRI扫描,运用T_2mapping序列、水-脂分离(IDEAL)成像技术对双侧大腿各肌肉水肿区域进行定量测值,并比较不同组别及各组不同肌肉的T_2mapping值、IDEAL序列值。结果:坏死性肌病组、多发性肌炎组的T_2mapping值高于对照组(P=0.021,0.012)。坏死性肌病组的IDEAL序列值高于对照组(P=0.039),其余组间差异无统计学意义(均P0.05)。坏死性肌病组与对照组T_2mapping序列有统计学差异的肌肉有:股外侧肌、股中间肌、股二头肌长头、半膜肌;多发性肌炎组与对照组T_2mapping序列有统计学差异的肌肉有主要有:股外侧肌、股中间肌、股内侧肌、股直肌、半膜肌。坏死性肌病组与对照组在IDEAL序列有统计学差异的肌肉有:股外侧肌、股中间肌、半膜肌。结论:本研究借助无创的MR序列,用定量的方式分析了坏死性肌病的肌肉受累特点和分布,对与其他类型的肌病鉴别提供参考。

Characteristics of Muscle Damage in Immune-Mediated Necrotizing Myopathy

To analyze the change in muscle damage under different imaging sequences using muscle MRI in patients of necrotizing myopathy, and to analyze the distribution of muscle damage. Methods: We recruited 16 patients with immune-mediated necrotic myopathy (IMNM) who were confirmed positive for SRP antibodies, 14 patients with polymyositis, and 18 healthy individuals of similar age and sex with no underlying illness. All subjects underwent thigh muscle MRI scans using T2 mapping and iterative decomposition of water and fat with echo asymmetric and least-squares estimation (IDEAL) to quantitatively measure values in regions of edema in muscles of both thighs. The values of T2 mapping and IDEAL were compared between the IMNM, polymyositis, and healthy control groups and between the muscles within each group. Results: The T2 values of the IMNM and polymyositis groups were higher compared with that of the control group (P=0.021, 0.012). The IDEAL value of the IMNM group was higher than that of the control group (P=0.039); the values showed no significant difference when compared between other groups (all P>0.05). When comparing the T2 mapping of individual muscle groups between the IMNM and control groups, statistical difference was found in the vastus lateralis, vastus intermedius, long head of the biceps femoris, and semimembranosus; comparing the polymyositis and control groups, statistical difference was found in the vastus lateralis, vastus intermedius, vastus medialis, rectus femoris, and semimembranosus. When comparing the IDEAL of individual muscle groups between the IMNM and control groups, statistical difference was found in the vastus lateralis, vastus medialis, and semimembranosus. Conclusion: This study demonstrates the use of the non-invasive MR sequence to quantitatively evaluate the characteristics and distribution of muscle involvement in IMNM and provides a possible approach for the identification of other myopathy types.