幕上原始神经外胚层肿瘤的CT、MRI和病理分析

目的探讨幕上原始神经外胚层肿瘤（PNET）的CT及MRI特点，以提高影像学诊断的准确性。资料与方法分析经手术病理证实的8例PNET的CT及MRI表现。结果8例PNET分别位于幕上大脑半球的额顶、额颞、枕叶、胼胝体区，病灶普遍较大，多为偏实性肿瘤，边界清晰，瘤周水肿较轻，其中病灶内囊变4例，合并出血3例，肿瘤T1WI呈稍低信号，T2WI呈稍高信号4例，T1WI、T2WI呈混杂信号3例，2例DWI显示呈高信号。增强检查肿瘤可表现为不均一强化、不规则“印戒”样强化，2例显示沿室管膜播散。结论PNET影像学表现有一定特征，影像学表现结合临床症状有助于与其他肿瘤区分。

CT,MRI and Pathological Analysis of Supratentorial Primitive Neuroectodermal Tumors

Objective To investigate the CT and MR/features of supratentorial primitive neuroectodermal tumors and improve the diagnostic accuracy. Materials and Methods The CT and MRI features of 8 cases with supratentorial primitive neuroectodermal tumors proved by operation and pathology were retrospectively analyzed. Results The lesions of 8 cases were located in supratentorial areas included frontoparietal lobe, frontotemporal lobe, occipital lobe and corpus callosum. The lesions were large in volume and clear margin, often with solid consistency and slight peritumor edema. Small cystic degeneration could be seen in 4 cases, hemorrhage in 3 cases. The lesions were demonstrated hypointensity on Tt and hyperintensity on T2 weighted in 4 cases,inhomogeneous intensity on T1WI and T2WI in 3 cases, hyperintensity on DWI in 2 cases, The lesions were usually inhomogeneous or irregular ring like enhanced on CT and MRI, and ependymal dissemination in 2 cases. Conclusion The CT and MRI features of supratentorial primitive neuroectodermal tumors are characteristic. Combining the CT and MRI features with related clinical symptoms, it is helpful to differentiate the tumor from other lesions.