肥胖细胞型星形细胞瘤的MRI表现:8例病例分析

MRI Diagnosis of Myxopapillary Ependymoma:8 Cases Report

目的探讨肥胖细胞型星形细胞瘤(Gem A)的MRI特点及鉴别诊断。方法回顾性分析经病理证实的8例Gem A的临床资料和MRI表现,8例均行MRI平扫及增强扫描,其中1例加扫磁敏感加权成像(SWI)序列,分析其影像特征。结果 8例Gem A全部位于幕上,均为单发,其中累及额叶7例,颞叶1例;4例累及多个脑叶,并通过胼胝体侵犯对侧脑组织;6例边界不清,2例边界清晰;肿瘤囊变4例;1例表现为大囊结节型,实性结节位于肿瘤脑膜面。肿瘤的实性成分在T1WI呈等或稍低信号,在T2WI呈稍高或高信号,在扩散加权成像(DWI)上呈稍高或高信号,ADC图呈等或低信号;增强后肿瘤实性成分多呈明显不均匀强化。结论 Gem A的MRI表现有一定特异性,单发,好发于额叶,边界不清,可囊变,可累及胼胝体侵犯对侧额叶,增强扫描后肿块实性成分明显强化。

Objective To explore the MRI features and differential diagnosis of gemistocytic astrocytoma（Gem A）.Methods MRI manifestations of 8 patients with Gem A confirmed by pathology were reviewed retrospectively.All of the patients underwent MRI plain and contrast-enhancement scan,one of them underwent magnetic susceptibility weighted imaging（SWI） scan.Results All 8 cases of Gem A were supratentorial and solitary.Of these 8 cases,7 cases were located in the lobus frontalis,1 case in the temporal lobe,4 case in the multiple lobar and invaded the opposite brain tissues through corpus callosum.6 cases presented with clear boundary,the other 2 cases have unclear boundary.4 of 8 cases（50%） had cystic changes,of which 1 case appeared large cystic nodules,and the nodules were located nearby the meninx of tumor.The solid part of tumors were isointense or slightly hypointense on T1 WI,isointense or slightly hyperintense on T2 WI,hyperintense or slightly hyperintense on DWI,isointense or hypointense on ADC map,and obviously heterogeneous enhancement on Enhanced MRI..Conclusion MRI manifestations of Gem A have some specificities,which are mainly single,mainly located in the frontal lobe,unclear boundary,mainly cystic malformation,and the opposite tissues can be invaded through corpus callosum with marked enhancement after Gd DTPA injection.