非典型部位可逆性后部脑病综合征的磁共振成像影像分析

Imaging findings and diagnosis of atypical sites posterior reversible encephalopathy syndrome

目的探讨两侧大脑后部以外非典型部位可逆性后部脑病综合征（PRES）的MRI特征，以提高诊断的准确性，并探讨其发病机制。方法回顾性分析9例非典型部位PRES的MRI影像资料，包括常规T1WI、T2WI、液体衰减反转恢复（FLAIR）及扩散加权成像（DWI），5例行MR动脉成像（MRA），4例行MR静脉成像（MRV）检查，3例接受MRI增强扫描。所有病例在3—14d内复查MRI。结果9例非典型PRES病例中，3例累及额叶，2例累及颞叶，2例累及两侧小脑半球，1例累及两侧基底节，单纯桥脑病变1例，左侧单侧病变1例；5例行MRA检查，其中1例MRA显示左侧颈内动脉节段性狭窄，4例MRA正常；4例MRV正常。3例MRI增强未见异常强化。所有病例3～14d复查病灶明显好转或完全消失。结论认识非典型部位PRES的MRI表现有利于正确诊断PRES，并对揭示其发病机制有帮助。

Objective To explore the magnetic resonance imaging（MRI） features of the posterior reversible encephalopathy syndrome （PRES） at atypical sites outside of the rear of cerebral hemispheres, in order to improve the accuracy of diagnosis and to explore its pathogenesis. Methods A retrospective analysis was made on the MRI image data of nine PRES cases in the atypical sites, including the conventional T1WI, T2 WI, fluid-attenuated inversion recovery（FLAIR） and diffusion weighted imaging （DWI）. Five cases had MRA examinations; four cases had MRV examinations and three cases had MRI enhancement scanning. The MRI of all patients was re-examined within 3 - 14 days. Results Among nine cases of PRES, three cases mainly had the frontal lobe ; two cases had the temporal lobe; two cases had both sides of the cerebellar hemispheres ; one case had both sides of the basal ganglia ; one case had pure pontine lesions ; one case had unilateral lesions of left frontotemporal lobe ; five cases underwent MRA examination, among them one case showed segmental stenosis of the left internal carotid artery and four MRA were normal;four MRV were normal. Among three cases of MRI enhancement, there was no abnormal enhancement. All lesions significantly improved or completely disappeared within 3-14 days. Conclusions Observing the MRI findings of PRES at atypical sites is helpful to correctly recognize PRES and the pathogenesis.