摘要
目的探讨MR扩散加权成像(DWI)对脑实质内表皮样囊肿(EC)的诊断价值。资料与方法回顾性分析6例脑实质内EC的常规MRI和DWI的信号特征。定量测定EC、正常脑白质和脑脊液(CSF)的平均表观扩散系数(mADC)值,并比较常规MRI和DWI各自诊断的准确性。结果(1)4例位于幕下小脑实质内,其中1例合并蛛网膜囊肿。1例呈巨块状跨左侧额、颞叶实质,另1例位于左颞叶内;(2)2例为均匀性长T1、长T2信号,类似CSF信号,4例表现为不均匀性囊实性混杂信号,其内可见漩涡状或卷发状短T1信号。所有病灶DWI上均表现为明显高信号、ADC图表现为等低、等高信号,部分病灶内信号不均;所有病灶均无灶周水肿信号;增强后均无异常强化;(3)所有EC的mADC值均较CSF值显著减低(t=39.97,P<0.001),较脑实质值显著增高(t=4.73,P<0.01);(4)单纯常规MRI对EC的诊断正确率为50%(3/6),结合DWI后的正确率为100%(6/6)。结论DWI有助于确诊脑实质内EC,对预防术中化学性脑膜炎的发生有重要意义。DWI应作为颅内囊性病灶检查时的常规序列。
Objective To evaluate the diagnostic value of MR diffusion-weighted imaging （DWI） in intraparenchymal epidermoid cysts （EC）. Materials and Methods 6 cases of histopathologically proven intraparenchymal EC were examined with conventional MR scan and DWI sequence. Along with mean ADC value （mADC） of the EC, CSF and the adjacent white matter（WM） were measured respectively. The qualitative and quantitative assessments,as well as MRI findings,were retrospectively analyzed in double blind by 2 radiologists in consensus. Results （ 1 ） Lesion locations：4 cases located in the cerebellum. Among them,one was accompanied with an arachnoid cyst;1 case with huge size crossed the parenchyma of the frontotemporal lobe;the other one located in the left temporal lobe. （2）MR findings：2 lesions were homogeneously CSF- like intensity on both T1WI and T2WI. The other 4 were mixed-intensity on both T1WI and T2WI. All lesions presented strikingly hyperintensity on DWI and iso-or slightly hypo-intensity on ADC （ relative to the brain）. （3） ADC value： the mADC of EC was significantly higher than that of WM,but significantly lower than that of CSF. （4）3 cases （3/6） were accurately diagnosed by the conventional MR sequences without DWI. All cases （6/6） diagnosed by the combination of MRI and DWI. Conclusion DWI sequence is very helpful to confirm the diagnosis of intraparenchymal EC, prevent chemical meningitis, and should be recommended as a routine examination in intracranial cystic lesions.
出处
《临床放射学杂志》
CSCD
北大核心
2008年第8期1010-1013,共4页
Journal of Clinical Radiology
关键词
表皮样囊肿
脑实质
脑
磁共振成像
扩散加权成像
Epidermoid cysts Intraparenchymal Brain Magnetic resonance imaging Diffusion weighted imaging
