MR imaging diagnosis of dermatomyositis: musculoskeletal findings / 中华放射学杂志

ABSTRACT

Objective To explore the musculoskeletal MR findings in dermatomyositis and to evaluate the role of MR in diagnosis of dermatomyositis. Methods Twenty patients with early dermatomyositis and 25 patients with active disease confirmed by pathology underwent T 1-weighted (SE 450/20), T 2-weighted (FSE 4000/100), and fat-suppressed MR images. MR findings in these 45 patients were analyzed. Results Within all the myositis, MR showed symmetrical slight high patchy signals on T 2-weighted and STIR images in the muscles of bilateral thighs, but the morphology of muscles appeared normal in 26 patients, while limited high signals only appeared on STIR image in 19 patients. There was correlation between serum muscle enzymes and the signal intensity as well as affected field of myositis. The myositis often affected gluteus and the external lateral muscles in the lower part of thighs. Inflammatory changes in the subcutaneous fat in 18 patients with active dermatomyositis were the severe appearance of the disease. Inflammatory fascia in 17 patients was found in both early and active cases. 5 patients had skin damage. Conclusion MR features of dermatomyositis are multiple myositis, fascia and subcutaneous inflammation, with the latter being an appearance of severe period of the disease. Early affected location of dermatomyositis is gluteus and the external lateral muscles in the lower part of thighs. MR is an efficient examination and STIR is a sensitive sequence in the diagnosis of dermatomyositis.