Application of Whole-body MRI in Idiopathic Inlfammatory Myopathy / 中国医学影像学杂志

ABSTRACT

PurposeTo investigate whole-body magnetic resonance imaging in diagnosis of idiopathic inflammatory myopathy (IIM), and to guide clinical treatment.Materials and Methods Twenty-six patients clinically diagnosed IIM including 19 dermatomyositis and 7 polymyositis were analyzed retrospectively. Whole-body MRI was performed in all patients including whole-body coronal scan and axial scan of both sides of thigh. Short tau inversion recovery (STIR) sequences were used in the coronal scan and T1WI and fat-suppressed T2WI were performed in the axial scan. Ten healthy volunteers were recruited as control group. MRI findings were compared between the two groups.Results Whole body MRI showed that muscles were homogeneously low signal intensity in the control group. Imaging findings of the patients with IIM included muscle inflammation, fascitis, subcutaneous tissue edema, muscle atrophy and fatty infiltration. The most common distribution site of muscle inflammation of dermatomyositis patients was thigh (n=18), followed by gluteus (n=14), great psoas muscle (n=13), shoulder muscles (n=11), leg muscle (n=11), erector spinae (n=10) and neck muscles (n=9). Findings out of muscles included cavities in the both lungs, infarction in femurs and tibias, avascular necrosis of femoral head, adrenal mass and thyroid nodules. The most common distribution site of muscle inflammation of polymyositis was thigh (n=5), followed by gluteus (n=3), great psoas muscle (n=3), shoulder muscles (n=2), leg muscles (n=2), erector spinae (n=1) and neck muscles (n=1). Findings out of muscles included 1 case of infarction in femurs and tibias.Conclusion Whole-body MRI can not only comprehensively evaluate the activity of IIM but also detect complications such as bone infarction. It's a powerful tool for diagnosis, guiding treatment and monitoring of IIM.