幕上原始神经外胚叶瘤的影像学表现

The image findings of supratentorial primitive neuroectodermal tumors

目的 探讨幕上原始神经外胚叶瘤 (SPNET)的MRI及CT特征。方法 回顾性分析 10例经手术病理证实的SPNET的MRI及CT表现。结果 SPNET的影像学表现有以下特点 :( 1)肿瘤呈类圆形 ,边界清楚 ,病灶周围无水肿或水肿较轻 ,且大部分位于中线附近及侧脑室旁 ,少数位于皮层下。 ( 2 )MRI示肿瘤实质T1WI呈稍低或等信号 ,T2 WI呈等信号 ,与脑灰质信号相等 ,增强较明显。 ( 3 )CT示肿瘤实质呈稍高密度 ,影像学表现与髓母细胞瘤相似。 ( 4)中线附近的肿瘤为实体结构 ,无囊变 ;囊变明显的肿瘤多位于皮质下。 ( 5 )部分肿瘤内有出血或钙化 ,有的可见到脑脊液扩散灶。结论SPNET影像学表现有一定特征 。

Objective To investigate the MRI and CT features of supratentorial primitive neuroectodermal tumors. Methods The MRI and CT features were retrospectively analyzed in 10 cases of supratentorial primitive neuroectodermal tumors proved by operation and pathology. Results The MRI and CT characteristics of supratentorial primitive neuroectodermal tumors were as follows: (1) The tumors located in supratentorium were sharply demarcated and surrounded by slight edema. The lesions tended to be roundish in shape. (2) The tumors appeared iso-signal or slight low signal on T 1WI and iso-signal on T 2WI; After contrast injection, the lesions usually enhanced markedly. (3) The tumors appeared slightly high density on CT imaging. The MRI and CT features of supratentorial primitive neuroectodermal tumors were similar to those of medulloblastoma. (4) The tumors located around midline appeared as solid structure. Cyst could be observed in tumors which located in infra-cortex. (5) Hemorrhage or calcification in tumors could be observed. The metastatic lesions through cerebrospinal fluid could be detected in a few cases. Conclusion The MRI and CT appearance of supratentorial primitive neuroectodermal tumors were characteristic. Combining the MRI and CT appearance with correlated clinical features, it is possible to differentiate the tumor from other lesions before operation.