双侧小脑后下动脉供血区急性脑梗死影像特征及病因探讨

目的:探寻双侧小脑后下动脉（PICA）供血区急性梗死的MRI特征及病因。方法:回顾性分析首都医科大学附属北京友谊医院2019年1月至2022年1月间经临床与影像学确诊的双侧PICA供血区急性梗死患者38例及双侧小脑上动脉（SCA）供血区急性梗死患者40例，按梗死大小、有无其他后循环供血区病灶、有无前循环供血区病灶，比较两组患者MRI特征差异，分析双侧PICA供血区急性梗死累及范围及椎-基底动脉改变。结果:双侧PICA供血区急性梗死表现为一侧区域梗死伴对侧小梗死的比例明显高于双侧SCA供血区梗死（39.5％ vs. 15％），而发生双侧小梗死的比例低于双侧SCA供血区梗死（44.7％ vs. 72.5％），合并后循环其他供血区梗死发生率明显低于双侧SCA供血区（21％ vs. 80％）；双侧PICA供血区急性梗死常表现为一侧全供血区受累伴对侧PICA内侧支（mPICA）供血区受累（44.7％）或双侧mPICA供血区受累（39.5％）；双侧PICA供血区急性梗死更常检出单侧椎动脉V4段或PICA局限性重度狭窄/闭塞（54.2％）。结论:双侧PICA供血区梗死主要表现为一侧全供血区受累伴对侧PICA供血区受累或双侧mPICA供血区受累，且区域性梗死常见，与解剖变异密切相关。 

Imaging Features and Etiology of Acute Cerebral Infarction in Bilateral PICA Territory

Objective: To investigate the MRI features and etiology of acute cerebral infarction in bilateral PICA territory. Methods: 38 patients with bilateral PICA and 40 patients with bilateral SCA diagnosed clinically and radiographically in Beijing Friendship Hospital of Capital Medical University from January 2019 to January 2022, were retrospectively analyzed. The difference of MRI features, were compared between the two groups, according to the size of the infarction, the distribution of infarcted lesions in posterior circulation or anterior circulation. The range of acute infarction in the bilateral PICA territory and the changes of vertebrobasilar artery were analyzed. Results: The proportion of the infarction model of one side regional infarction with the other side small infarct in bilateral PICA was significantly higher than that in bilateral SCA (39.5% vs. 15%), while the model of small infarction on both sides was lower than that in bilateral SCA (44.7% vs. 72.5%). The incidence of infarction in other blood supply areas of the combined posterior circulation was significantly lower than that in bilateral SCA (21% vs. 80%). The infarction models of bilateral PICA manifested as unilateral total infarct of PICA territory combined with the other unilateral infarct of mPICA territory (44.7%) or bilateral mPICA territory (39.5%). Unilateral vertebral artery V4 segment or PICA-localized severe stenosis/occlusion were more frequently detected in acute infarcts in bilateral PICA (54.2%). Conclusions: Bilateral PICA territory infarction mainly manifested as unilateral total infarct of PICA territory combined with the other unilateral or bilateral infarct of mPICA territory, and regional infarction was quite common, which was closely related to anatomical variation.