肥胖细胞型星形细胞瘤的MRI表现探讨

摘要

目的 初步探讨肥胖细胞型星形细胞瘤(Gemistocytic Astrocytoma,GemA)的MRI表现及功能成像特点,以提高对该病的认识及诊断水平.方法 回顾性分析2010年10月~2015年12月经手术及病理证实的13例GemA患者的临床及影像资料,所有患者均行MRI平扫、增强,其中9例加扫磁共振波普(Magnetic Resonance Spectroscopy,MRS)、弥散张量成像(Diffusion Tensor Imaging,DTI)、动脉自旋标记技术(Arterial Spin Labeling,ASL)及灌注加权成像(Perfusion Weighted Imaging,PWI)成像,1例加扫磁敏感加权成像(Susceptibility Weighted Imaging,SWI)序列,分析总结其MRI影像特征.结果 13例患者均为单发病灶,且均发生于幕上,其中发生于额叶10例,颞叶2例,顶叶1例;8例病灶局限于单脑叶,5例累及多个脑叶,并通过胼胝体侵犯对侧脑组织;边界不清8例,边界清楚5例;肿瘤内部有大小不等囊变成分7例.肿瘤的实性成分在T1WI呈稍低信号,T2WI呈稍高信号,DWI呈稍高信号,增强后肿瘤实性成分多呈中度及以上不均匀强化;MRS表现为Cho峰升高,NAA峰减低,Cr峰基本稳定;ASL及使用PWI均呈低灌注,DTI显示患侧大脑皮质纤维束明显较对侧稀疏.结论 GemA的MRI表现为幕上单发,额叶多见,多边界不清且内部常伴囊变,并累及胼胝体侵犯对侧脑叶,增强扫描肿块实性成分多中度及以上不均匀强化,结合MRS、DTI、ASL、SWI及PWI,可对本病提供诊断帮助.%Objective To preliminarily investigate the MRI manifestations and imaging features of gemistocytic astrocytoma (GemA) so as to improve the level of recognition and diagnosis of the disease. Methods The clinical and imaging data of 13 patients with GemA, diagnosed via surgery as well as pathology from October 2010 to December 2015, were reviewed retrospectively. All patients were performed by both plain and enhanced MRI scanning. 9 cases of them still were performed with magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), arterial spin labeling (ASL) and perfusion weighted imaging (PWI) scanning,along with 1 case through susceptibility weighted imaging (SWI) sequence. Then the related MRI imaging features were analyzed and summarized.Results 13 GemA patients were all solitary lesions and located at supratentorial sites, with 10 cases located in the frontal lobe, 2 cases in temporal lobe, 1 case in parietal lobe. Of these 13 cases, 8 cases were confined to single lobe lesion, 5 cases were involved in multiple lobe which invaded the opposite brain tissue through corpus callosum; 8 cases had unclear boundary, the other 5 cases presented with clear boundary; 7 cases showed multiple and various sizes of cystic lesions in solid part. The solid portions of the tumor demonstrated slightly hypo intense on T1WI, slightly hyper intense on T2WI and DWI, and obviously uneven enhancement in moderate or above level; MRS characterized that Cho (choline) peak increased, NAA (N-acetyl aspartic acid) peak decreased and Cr (creatine) peak was basically stable; ASL and PWI presented hypoperfusion, DTI showed lateral cortical fiber bundle was sparser obviously than contralateral side.Conclusion MRI manifestations of GemA were mainly single, located in the frontal lobe, much unclear boundary with cystic change inside, invading the opposite tissues through corpus callosum, and uneven enhanced in moderate or above level to solid elements of tumor. What's more, MRS, DTI, ASL, SWI and PWI could be combined with MRI to help diagnose the disease.