Abstract: Objective  To investigate the relationship between the geometric shapes of the vertebrobasilar artery (VBA) and the occurrence, distribution, and characteristics of the basilar artery (BA) plaques in patients with symptomatic acute ischemic stroke (AIS) in the posterior circulation using high resolution vessel wall imaging (HR-VWI). 
Methods  Patients with symptomatic AIS in the posterior circulation who were hospitalized in the Department of Neurology of Shenzhen Baoan People’s Hospital from June 2017 to December 2021 were retrospectively and consecutively included. According to the presence or absence of atherosclerotic plaque in the BA on HR-VWI, the patients were divided into the plaque group and the nonplaque group. The baseline characteristics, BA-vertebral artery (VA) angle, BA-middle angle, and BA tortuosity rate of the two groups were compared. According to 3D-TOF-MRA, the VBA geometric shapes of patients were divided into walking type, tuning fork type, λ type, and unilateral VA non-merging type. The incidence of BA plaques in the four VBA geometric shapes was statistically analyzed. The BA-VA angle, BA-middle angle, BA tortuosity rate, plaque distribution, external lumen diameter, plaque volume, external vessel wall area, vessel wall area, plaque thickness, plaque burden (PB), and enhancement rate (ER) of the four VBA geometric shapes were compared.
Results  A total of 71 patients were included, of which 54 (76.1%) had plaques and 17 (23.9%) did not. There was no statistically significant difference in the baseline characteristics and VBA morphological features between the plaque group and the nonplaque group (all P>0.05). Among the four VBA geometric shapes, the incidence of BA plaques in the walking type was higher than that in the tuning fork type (92.3% vs. 55.6%, P=0.033). The BA-middle angle in the tuning fork type [(166.83±13.27)° vs. (150.77±19.65)°, P=0.008)] and the λ type [(163.82±12.36)° vs. (150.77±19.65)°, P=0.028)] was greater than that in the walking type. The tortuosity rate of the BA in the walking type among the four VBA geometric shapes was the highest (P=0.005). However, there was no statistically significant difference in the distribution of BA plaques among the four geometric shapes (P=0.109), and there was no statistically significant difference in plaque characteristics, PB, and ER (all P>0.05). 
Conclusions  The geometric shapes of the VBA in patients with symptomatic AIS in the posterior circulation is closely related to the occurrence of BA plaques. Compared with the tuning fork type, the walking type is more likely to have BA plaques, and the BA in the walking type among the four geometric shapes is more likely to bend.

Key words: Atherosclerosis; Plaque; High resolution vessel wall imaging; Symptomatic acute ischemic stroke in the posterior circulation; Vertebrobasilar artery geometric shape

摘要： 目的 利用高分辨率血管壁成像（high resolution vessel wall imaging，HR-VWI）研究后循环症状性急性缺血性卒中（acute ischemic stroke，AIS）患者椎基底动脉（vertebrobasilar artery，VBA）几何形态与基底动脉（basilar artery，BA）斑块的发生、分布及特征之间的关系。 
方法 回顾性连续纳入2017年6月—2021年12月在深圳市宝安区人民医院神经内科住院治疗的后循环症状性AIS患者，根据HR-VWI上BA是否存在动脉粥样硬化斑块将患者分为有斑块组和无斑块组，比较两组患者的基线特征、BA-椎动脉（vertebral artery，VA）角、BA-中角、BA曲折率。再根据3D-TOF-MRA将患者的VBA几何形态分为步行型、音叉型、λ型和一侧VA不汇入型，统计4种VBA几何形态BA斑块的发生率，并比较4种VBA几何形态的BA-VA角、BA-中角、BA曲折率、斑块分布、外管腔直径、斑块体积、血管外壁面积、血管壁面积、斑块厚度、斑块负荷（plaque burden，PB）、斑块强化率（enhancement rate，ER）的差异。
结果 共纳入71例患者，其中54例（76.1%）有斑块，17例（23.9%）无斑块。有斑块组和无斑块组患者的基线特征和VBA形态特征的差异无统计学意义（均P＞0.05）。在4种VBA几何形态中，步行型的BA斑块发生率高于音叉型（92.3% vs. 55.6%，P=0.033）。音叉型[（166.83±13.27）°vs.（150.77±19.65）°，P=0.008）]和λ型[（163.82±12.36）°vs.（150.77±19.65）°，P=0.028）]的BA-中角均大于步行型。4种VBA几何形态中步行型的BA曲折率最大（P=0.005）。4种几何形态的BA斑块分布差异无统计学意义（P=0.109），斑块特征、PB和ER等差异也无统计学意义（均P＞0.05）。
结论 后循环症状性AIS患者的VBA几何形态与BA斑块的发生密切相关，相较于音叉型，步行型更容易发生BA斑块，4种VBA几何形态中步行型的BA更容易弯曲。

关键词: 动脉粥样硬化; 斑块; 高分辨率血管壁成像; 后循环症状性急性缺血性卒中; 椎基底动脉几何形态