单纯疱疹病毒性脑炎的CT及MRI表现

CT and MRI manifestations of herpes simplex virus encephalitis

目的:探讨单纯疱疹病毒性脑炎的影像学表现。方法:回顾性分析9例经PCR(polymerase chain reaction)证实的单纯疱疹病毒性脑炎患者的影像及临床资料,9例患者均行颅脑MRI及增强检查,3例行头部CT扫描。结果:2例病灶位于单侧颞叶、岛叶和扣带回;2例位于双侧颞叶,岛叶、基底节、额叶内侧回及海马钩回;5例位于双侧额叶、颞叶、岛叶,一侧为重,病灶多累及皮层及皮层下白质;其中2例出现不同程度的占位效应。CT扫描病灶呈低密度;MRI扫描病灶呈长T1长T2信号,TIRM序列上病灶呈高信号,DWI显示病灶区扩散受限,增强扫描5例出现脑膜样强化,4例无强化。结论:单纯疱疹病毒性脑炎影像学表现具有一定特征性,常侵犯颞叶、额叶、基底节及岛叶,尤其一侧颞叶、岛叶和眶额区为重。MRI对病灶的显示优于CT。

Objective： To investigate the imaging appearance of herpes simplex virus encephalitis. Methods： Imaging and clinical data from nine patients with herpes simplex virus encephalitis proved by PCR were retrospectively analyzed. Nine patients all received MRI and dynamic contrast enhancement scanning and 3 received CT scanning. Results： The majority of lesions were located in the unilateral temporal lobe,insula and cingulate gyrus （n= 2）, bilateral temporal lobe, insular lobe, basal ganglia, medial frontal gyrus and the hippoeampal uneus （n： 2）, or bilateral frontal lobe, temporal lobe, insular lobe, with one side heavier, lesions mostly involving the cortex and subeortical white matter （n=5） ;among them 2 cases had different degree of occupying effect. CT scan showed low density. MRI scan showed long T and long T2 signal intensity, TIRM sequence showed high signal, DWI showed restricted diffusion, enhanced scan showed mild meningeal enhancement （n=5） or nonenhancement （n= 4）. Conclusions： Herpes simplex virus encephalitis often involves one side of the brain, espe-cially temporal lobe,insular and orbitofrontal area with asymmetric distribution. As to the imaging manifestations, MRI is better than CT.