颅内表皮样囊肿的CT、MRI及DWI诊断

目的:通过分析55例颅内表皮样囊肿CT、MRI和DWI表现,探讨表皮样囊肿的影像学诊断和鉴别诊断。方法:对55例经手术病理证实的颅内表皮样囊肿的CT、MRI及DWI表现进行回顾性分析。男33例,女22例。全部病例均行MR平扫检查,其中26例行MR增强扫描,18例行扩散加权成像,26例行CT平扫检查,5例行CT增强扫描。结果:表皮样囊肿位于脑外29例,脑实质23例,脑室3例。CT平扫24例呈低密度,2例密度稍高于脑实质。51例类似脑脊液信号,1例呈短T1短T2信号,2例呈短T1长T2信号,1例T1WI大部分呈等信号,少部分为低信号,T2WI呈低信号。2例囊壁似有轻微强化。DWI上囊肿均表现为高信号,且ADC值高于脑实质。结论:形态不规则、类似脑脊液信号、DWI呈高信号、不强化是表皮样囊肿的影像学表现特点,不典型表皮样囊肿可呈其它密度和信号变化,可根据不强化和DWI呈高信号与其它类似病变鉴别。

CT,MRI and DWI Diagnosis of Intracranial Epidermoid Cysts

Objective:To discuss intracranial epidermoid cysts' imaging diagnosis and differential diagnosis by analyzing the features of them on CT,MRI and DWI.Methods:55 patients including 33 males and 22 females with intracranial epidermoid cysts proven pathologically were examined with CT,MRI and DWI.All patients were examined with MR plain scans and 26 of them were done with MR contrast scans.18 lesions were done with DWI.26 lesions were with CT plain scans,and 5 of them were examined together with CT contrast scans.Results:Of 55 lesions,29 were located outside of the encephalon,23 in the encephalon and 3 in the ventricles.On CT,24 cases were hypodense,2 slightly higher than encephalon.On MR,51 cysts demonstrated the signals like CSF.1 showed short T_1 and short T_2 signals;2 showed short T_1 and long T_2 signals;1 showed isosignal of its most part on T_1WI and hyposignal of the rest part,and hyposignal on T_2WI.2 cases were with slightly enhanced cystic edge.All cases were hyperintensity on DWI,and the values of ADC were higher than encephalon.Conclusion:Irregular shape and similar signals like CSF,hyperintensity on DWI and non-contrast are the imaging characters of epidermoid cysts.The uncharacteristic epidermoid cysts could demonstrate other changes on CT and MRI and be differentiated with other similar disease according to the points of non-contrast and hyperintensity on DWI.