中枢性原始神经外胚层肿瘤的CT和MRI表现

目的探讨中枢性原始神经外胚层肿瘤(primitive neuroectodermal tumor,PNET)的影像表现特征,以提高对此病的认识。方法回顾性分析经手术病理证实的9例PNET患者的CT和MRI资料。结果发生于大脑半球7例,脑干及松果体区各1例。9例病灶边界均清晰,密度或信号不均匀。CT平扫实质部分与脑灰质等或稍高密度,MRI上T1WI呈与脑灰质等或稍低信号,T2WI呈等或稍高信号。7例无或轻度瘤周水肿;6例有明显占位效应;瘤内出血6例,钙化5例;6例见流空血管信号穿行,6例与侧脑室关系密切。5例与局部硬脑膜相连,其中2例邻近骨质变薄,增强扫描多明显强化。结论 PNET影像学表现有一定特征性。

CT and MRI Findings of Primitive Neuroectodermal Tumors in the Central Nervous System

Objective To investigate the imaging features of primitive neuroectodermal tumors(PNET) in the central nervous system,so as to improve its recognition.Methods The CT and MR images of 9 cases with pathologic confirmed PNET were analyzed retrospectively.Results Of the 9 cases with PNET,7 cases were located in the hemicerebrum,1 case was in the brainstem and 1 in the pineal region.All the 9 lesions were well defined and manifested as inhomogeneous signal or density.The solid component of the tumors appeared as iso or slight hyperdensity comparable with gray matter on CT.On MRI,the solid component was isointensity signal or slightly hypointensity on T1WI and isointensity or slightly hyperintensity signal on T2WI.There were no or slight peritumoral edema in 7 cases and 6 cases showed obvious mass effect.Hemorrhage could be seen in 6 cases,calcification in 5 cases and signal voids of vessel in 6 cases.The lesions had a relationship with lateral ventricle in 6 cases and connected with local dura mater in 5 cases,of which the adjacent bone became thinner in 2 cases.Most of the tumors demonstrated obvious enhancement.Conclusion The imaging appearance of PNET has some characteristics.