化脓性肌炎的MRI表现

目的分析化脓性肌炎的MRI表现特点。方法回顾分析我院经临床手术及病理证实的8例化脓性肌炎患者的MRI表现。检查序列包括SET1W、TSET2W、STIR，其中4例同时接受增强SET1w扫描。结果8例中1例发生于腰大肌，余7例均发生于下肢肌肉。MRI显示所有8例受累肌肉弥漫性肿大，T2WI表现为较明显不均匀高信号，STIR为明显高信号；T1WI呈与邻近肌肉等、稍低或稍高信号改变，邻近肌间隙水肿。4例病灶中见单个或多个T1WI低信号、T2WI高信号脓肿形成，周围脓肿壁在T1WI上为相对高信号。增强扫描中2例受累肌肉呈明显弥漫性强化，2例脓肿形成呈环状强化，脓腔及小的炎性坏死区无强化。结论MRI可清晰显示化脓性肌炎病变部位、特点及范围，具有重要诊断价值。

MRI features of pyomyositis

Objective To investigate the MRI features of pyomyositis (PM). Methods MRI features of 8 PM patients confirmed by operation and pathology were retrospectively analyzed. Images of SE T1W, TSE T2W and STIR sequence were obtained in all cases. After Gd-DTPA injection, SE T1WI were obtained in 4 cases. Results The psoas was involved in 1 patient, while lower extremity large muscles involvement occurred in the other 7 cases. MRI showed diffuse enlargement of involved muscles in all of 8 cases. The involved muscles demonstrated as heterogeneously high signal intensity on T2WI, and obviously high signal intensity on STIR, isointensity, slight low or slight high signal intensity on T1WI, and adjacent intermuscular spaces edema. Four patients had single or multiple hypointense fluid collections with hyperintense rim on T1WI, which had high signal intensity and hypointense rim on T2WI. On contrast-enhanced T1WI, obviously diffused enhancement of the involved muscles was noticed in 2 cases, and peripheral rim enhancement was found in 2 cases, but the small focal areas of inflammatory muscular necrosis and the fluid collection areas did not enhance. Conclusion MRI can clearly display the location, characteristics and range of pyomyositis, is of important value in diagnosing pyomyositis.