颅内表皮样囊肿的CT、MRI诊断

目的　分析颅内表皮样囊肿的CT、MRI表现。方法　对 18例经手术、病理证实的颅内表皮样囊肿的CT、MRI表现作了回顾性分析。 18例表皮样囊肿均作了MRI平扫和增强扫描 ,其中 12例还作了CT平扫检查。对肿瘤发生部位、大小、形态、CT密度、MRI增强前后的信号强度以及邻近结构的改变作了观察。结果　肿瘤位于桥小脑角区 10例 ,鞍上或鞍旁 3例 ,松果体区和第四脑室内各 2例 ,小脑延髓池 1例。肿瘤大小不等 ,形态多呈不规则形 ,轮廓光整或呈分叶状。CT平扫 10例呈均匀低密度 ,2例呈稍不均匀的低密度 ,CT值在 -15～ 10HU之间。在MRT1WI图像上肿瘤呈不均匀的低信号 ,在T2 WI、FLAIR图像上均呈不均匀的高信号。增强后除 1例肿瘤边缘似有轻微强化外 ,其余肿瘤均无明显的强化。结论　典型的颅内表皮样囊肿的CT、MRI表现较具特征性 ,通过CT、MRI检查可以作出准确诊断 ,并能与其他类似的颅内病变鉴别

CT and MRI Diagnosis of Intracranial Epidermoid Cysts

Objective To analyze the features of intracranial epidermoid cysts on CT and MR imaging.Methods 18 patients with intracranial epidermoid cysts proven pathologically were examined with pre-and post-contrast enhanced MR imaging,and 12 of 18 patients also undergone CT plain scan.CT and MR images of 18 cases were reviewed retrospectively.The size,shape,contour and the changes of surrounding structures of the tumors were noted.Results Of 18 cases of intracranial epidermoid cysts,10 were located in the cisterns of cerebellopontine angle,3 in the suprasellar or parasellar regions,2 in the pineal regions and fourth ventricles respectively,and 1 in the cerebellomedullar cistern.The tumors differed in size from 1.8 to 6.5 cm,and irregular shapes were noted in most of the tumors with lobulated or smooth contour.On CT ,10 cases were homogeneous hypodense,2 slightly inhomogeneous hypodense from-15 to 10 HU in CT values.The tumors demonstrated inhomogeneous hypointensity on T 1-weighted MR images,and inhomogeneous hyperintensity on T 2-weighted and FLAIR MR images.No contrast enhancement was noted in all tumors except on with slight periphery enhancement.Conclusion The CT and MR features of intracranial epidermoid cysts were characteristic.Epidermoid cysts could be diagnosed accurately and differentiated from other similar cystic lesions with CT and MR imaging.