目的：探讨胸膜外孤立性纤维瘤的CT和MR表现，以提高对本病的诊断水平。方法：回顾性分析7例经手术病理证实的胸膜外孤立性纤维瘤的CT和MR表现。结果：7例中发生于腹部3例（其中腹腔、腹膜后、腹膜各1例），鼻窦及鼻腔、腮腺、腹股沟区、膀胱各1例。4例肿瘤呈圆形或卵圆形，3例呈分叶状，5例边界清楚，2例边界欠清，肿瘤直径2.0~9.1 cm，平均6.5 cm。CT扫描示2例密度均匀，4例密度不均，增强后1例呈早期轻度强化，另3例肿瘤动脉期明显强化，延迟期持续强化。MR T1WI呈低信号，T2WI呈略低信号1例，T1WI呈等信号，T2WI呈稍高信号1例，内部见条片状T2WI低信号。结论：胸膜外孤立性纤维瘤可发生于全身任何部位，CT和MR表现具有一定特征性，多期增强扫描可以提高诊断准确性。

Objective: To investigate CT and MR findings of extrapleural solitary fibrous tumor(ESFT) for imaging diagnosis. Methods: The CT and MR findings of 7 cases with ESFT proved by pathology were retrospectively analyzed. Results: In 7 cases, 3 cases were located in the abdomen(intraabdominal, retroperitoneal and peritoneal respectively), and 1 in nasal cavity and sinuses, 1 in parotid gland, 1 in inguinal region and 1 in bladder respectively. All masses were solitary, four were round or oval, while 3 were irregular. Margins of 5 cases were well defined, while 2 were partly unclear. Diameters of the tumors ranged from 2.0~9.1 cm, and the average tumor size was 6.5 cm. The CT density was homogeneous in 2 cases and heterogeneous in 4 cases. Contrast enhanced CT showed early mild enhancement in 1 case, and obvious enhancement in the arterial and delay phases in 3 cases. On MR, one was hypointense on T1WI and slightly hypointense on T2WI. One was isointense on T1WI and slightly hyperintense on T2WI with strip hypointensity. Conclusion: ESFT can be found in any part of the body. CT and MR findings of ESFT were sometimes characteristic and multiphase contrast enhanced scan can improve the diagnostic accuracy.