目的探讨中枢神经系统原始神 经外胚层肿瘤的MRI特点，以此提高CNS PNET的诊断率。方法 回顾性分析12例经 病理证实的CNS PNET的MRI资料。结果 本 组12例患者均行MRI平扫加增强，其中男6 例，女6例，年龄分布为1-48岁。病灶多 位于大脑半球深部，以颞叶多见，1例颅 内播散。实性肿块7例，囊实性5例,肿块 边缘较清楚，瘤周轻微水肿； MRI平扫信 号欠均匀，实质部分T1WI呈低及等低信 号，T2WI呈高及稍高信号,DWI呈高信号， 囊性部分T1WI呈低信号，T2WI呈高信号； 增强扫描5例呈环形强化，7例呈不均匀强 化。结论 原始神经外胚层肿瘤的MRI表 现具有一定特点，但确诊仍需依赖病理诊 断。

Objective To explore the MRI features of primitive neuroectodermal tumors of central nervous system (CNS PNET) in order to improve the diagnosis of MRI in CNS PNET. Methods MRI imaging data of twelve cases with CNSPNET which confirmed by pathology were analyzed retrospectively. Results The 12 cases both underwent MRI plain scan and enhancement, 6 males and 6 females, aged from 1 to 48 years. The lesions were commonly found in the deep cerebral hemisphere, and more commenly in the temporal lobe, and one case spreaded in the cerebral. In the 12cases,7 were solid mass and 5 were cystic and solid mass, all the tumors had clear boundary as well as slight peritumoral edema. MRI images showed the solid part of the tumors to be middle or hypointense on T1 weighted images and hyperintense on T2 weighted images as well as hyperintense on DWI images. The cystic component to be hypointense on T1 weighted images and hyperintense on T2 weighted images. The enhancement images showed that 5 cases had a ring enhancement, and the other 7 cases had a heterogeneous enhancement. Conclusion Certain MRI features may suggest the diagnosis of CNS PENT, but still rely on pathological diagnosis.