脑实质内室管膜瘤的MRI诊断分析

MRI Diagnosis of Intraparenchymal Ependymomas: A Clinical Analysis

目的探讨脑实质内室管膜瘤的MRI特征,以期提高诊断水平。方法回顾性分析15例经手术病理证实的脑实质内室管膜瘤MR平扫及增强扫描资料,并与术后病理对照。结果本组15例,10例肿瘤位于幕上,5例位于幕下,幕上者体积一般较幕下者大。14例与脑室关系密切。11例为囊实性型(其中1例为大囊为主型),3例为实质型,1例为囊性型,肿瘤实质部分T1WI呈等或稍高信号,T2WI及FLAIR呈高信号,囊性部分呈长T1、长T2信号;3例伴有出血灶;8例伴瘤周水肿;增强扫描瘤体不均匀明显强化,11例实质部分可见强化血管;1例行MRS分析,NAA峰明显降低,Cho峰明显升高。结论脑实质内室管膜瘤误诊率较高,但其MR表现有一定特征性,对术前诊断有一定价值,确诊依靠病理检查。

Objective To analyze MRI features of intraparenchymal epen dymomas in order to improve the diagnostic level. Methods The clinical data and the both plain and contrast-enhanced MR manifestations of 15 cases with pathologically-proved intraparenchymal ependymoma were retrospectively analyzed,and the findings were compared with the pathological results. Results Among the 15 cases,the lesions were located at the supratentorial cerebrum in 10,at the infratentorial cerebrum in 5. Usually,the lesions located at supratentorial cerebrum were larger than those located at infratentorial cerebrum. In 14 cases,the lesion＇s location showed a close anatomical relationship with the ventricle. Of 11 cases,the lesion was solid cystic type in 10 and large cystic type in one. Solid type was seen in 3 cases and cystic type in one case.On T1 WI the lesion＇s parenchyma presented as iso-intense or slight hyper-intense signals,while presented as hyper-intense signals on T2 WI and FLAIR. The cyst fluid was marked by long T1 and long T2 signals. Evident hemorrhage was seen in 3cases,and peritumoural edema was detected in 8 cases. Contrast-enhanced MR scanning revealed that the lesions had inhomogeneous enhancement,and enhanced vasculature could be demonstrated within the lesion＇s parenchyma（ n = 11）. MR spectrum analysis was carried out in one case,which indicated that NAA peak was distinctly decreased while Cho peak was sharply increased. Conclusion Although the rate of misdiagnosis for intraparenchymal ependymomas is higher,this tumor has some specific MRI features,which are helpful in making the diagnosis before surgery. However,the confirmation of the diagnosis depends on the pathological examination.