Van De Vlekkert Janneke, Maas Mario, Hoogendijk Jessica E, De Visser Marianne, Van Schaik Ivo N
Department of Neurology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
Muscle Nerve. 2015 Feb;51(2):253-8. doi: 10.1002/mus.24307.
In 10-20% of patients with subacute-onset idiopathic inflammatory myopathy (IIM), muscle biopsy is normal or shows nonspecific findings. MRI can be used as a triage test before muscle biopsy and as an add-on test if the biopsy is nondiagnostic.
MRI scans of skeletal muscles and muscle biopsies were evaluated prospectively in 48 patients suspected to have IIM. The interpretations of MRI and muscle biopsy were compared with the definite diagnosis (based on European Neuromuscular Centre criteria and response to corticosteroids).
The false negative rate (FNR) of all muscle biopsies was 0.23. Biopsies of a muscle showing hyperintensity on MRI (as triage test) had an FNR of 0.19. The result of MRI as an add-on test in patients with a nondiagnostic muscle biopsy decreased the FNR from 0.23 to 0.06.
We recommend both MRI and muscle biopsy in patients suspected of having IIM.
在10%至20%亚急性起病的特发性炎性肌病（IIM）患者中，肌肉活检结果正常或显示非特异性表现。MRI可在肌肉活检前用作分流检查，若活检无法确诊，也可作为补充检查。
对48例疑似患有IIM的患者进行了骨骼肌MRI扫描和肌肉活检的前瞻性评估。将MRI和肌肉活检的结果与明确诊断（基于欧洲神经肌肉中心标准和对皮质类固醇的反应）进行比较。
所有肌肉活检的假阴性率（FNR）为0.23。对MRI显示高信号的肌肉进行活检（作为分流检查）的FNR为0.19。在肌肉活检无法确诊的患者中，MRI作为补充检查的结果使FNR从0.23降至0.06。
我们建议对疑似患有IIM的患者同时进行MRI和肌肉活检。
