摘要目的:探讨单侧椎动脉V4段闭塞性病变（重度狭窄或闭塞）时，对侧椎动脉可以通过血流代偿，反向供血到病变侧小脑后下动脉（PICA）的椎动脉V4段窃血的临床特征。方法:病例系列研究。回顾性收集2020年6月至2022年10月齐齐哈尔医学院附属第二医院脑血管狭窄诊断与介入治疗中心以及解放军总医院第六医学中心神经内科诊治的66例单侧椎动脉V4段闭塞性病变病例，分析其血流动力学特点及影像学资料。结果:66例中有11例（16.7%）V4段闭塞性病变患者的数字减影血管造影（DSA）上可见病变对侧椎动脉血流可通过椎基底动脉汇合点经过同侧椎动脉V4远端逆向窃至病侧小脑后下动脉，该途径鲜见文献报道，根据既往锁骨下动脉窃血和颈动脉窃血定义的特点，我们称该途径为椎动脉V4段窃血。其中6例（9.1%）患者经颅多普勒超声（TCD）、经颅彩色多普勒超声（TCCD）上可见患侧椎动脉V4段近端未探及血流信号，V4段远端（PICA以远）及PICA均可见正向血流信号，对侧椎动脉V4段血流速度代偿性增快。结论:椎动脉V4段窃血是非常少见的椎动脉窃血途径，椎动脉V4段闭塞时，临床医生应注意观察PICA的供血情况以及是否存在该窃血途径，以期更好地评估患者的血流代偿及预后。

abstractsObjective:To explore the clinical characteristics of unilateral vertebral artery V4 segment occlusive lesions (severe stenosis or occlusion), where the contralateral vertebral artery can be compensated through blood flow and reverse supply to the posterior inferior cerebellarartery (PICA).Methods:This study is a retrospective case series of 66 patients with V4 segment occlusive lesions of unilateral vertebral artery diagnosed and treated from June 2020 to October 2022. Patient data were retrospectively collected, and their hemodynamic characteristics and imaging data were analyzed.Results:Of the 66 cases, 11 patients (16.7%) with V4 segment occlusive disease showed the blood flow of the vertebral artery on the opposite side of the lesion on the digital subtraction angiography (DSA), which can be reverse stolen to the posterior inferior cerebellar artery of the diseased side through the confluence point of the vertebrobasilar artery through the distal end of the ipsilateral vertebral artery V4. Owing to the lack of literature on this pathway and based on the characteristics of previous definitions of subclavian artery steal and carotid artery steal, we referred to this pathway as the vertebral artery V4 segment steal. In 6 patients (9.1%), transcranial Doppler ultrasound (TCD) and transcranial color Doppler ultrasound (TCCD) showed that the blood flow signal was not detected at the proximal end of the V4 segment of the affected side, rather the blood flow direction was reversed at the distal end of the V4 segment, resulting in compensatory acceleration of the blood flow velocity of the V4 segment of the contralateral vertebral artery.Conclusion:“V4 segment steal of vertebral artery” is a very rare route of vertebral artery steal. When V4 segment of the vertebral artery is occluded, clinicians should pay attention to observe the blood supply of PICA and whether there is such a steal route, to better evaluate the blood flow compensation and prognosis of patients.