椎动脉发育不全对小脑后下动脉供血区脑灌注的影响

目的探讨椎动脉发育不全(vertebral artery hypoplasia,VAH)对小脑后下动脉供血区脑灌注的影响。方法选择2014-12—2015-07年龄≥30岁并行头颅磁共振灌注成像和头颈部三维对比增强磁共振血管造影检查的头晕或眩晕患者244例。获脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)和达峰时间(TTP)灌注图,测量一侧小脑后下动脉供血区及对侧镜像区的灌注参数值(CBF、CBV、MTT、TTP),计算椎动脉直径较小侧/对侧镜像区的灌注参数相对比值(rCBF、rCBV、rMTT、rTTP)。定义VAH为椎动脉直径≤2mm,或双侧椎动脉不对称比≥1.7:1,分为VAH组和non-VAH(Nonhypoplasitic vertebral artey)组,对临床资料和小脑、延髓灌参数相对比值进行比较。结果共纳入114例患者,男女各57例;VAH组31例(27.2%),左侧5例(16%),右侧26例(84%);Non-VAH组83例。2组间VA直径较小侧与对侧的rTTP和rCBF≤0.85的例数存在显著统计学差异(P值分别为0.005,0.031);rCBF倾向于有统计学差异(P=0.098);rCBV、rMTT及rCBV≤0.85例数无显著统计学差异。结论 VAH可以造成小脑后下动脉供血区域低灌注改变,且以TTP延长或CBF降低为主。

Effect of vertebral artery hypoplasia on the territory-related perfusion of posterior inferior cerebellar artery

Objective To investigate the effect of vertebral artery hypoplasia on the territory perfusion of posterior inferi-or cerebellar artery (PICA).Methods 244 patients with vertigo or dizziness (age≥30 years old)from December 2014 to July 201 5 were selected as subjects who underwent brain perfusion-weighted imaging (pWI)and three-dimensional dynamic con-trast-enhanced MRA (3D DCE-MRA).The perfusion figures of cerebral blood flow(CBF),cerebral blood volume(CBV),mean transit time(MTT)and time to peak(TTP)were obtained.The perfusion parameters including CBF,CBV,MTT and TTP val-ues were measured at PICA areas and at the opposite mirror-imaging areas.Relative perfusion parameter values (rCBF,rCBV, rMTT and rTTP)defined as the ratio of the shorter diameter side of vertebral artery to the mirror-imaging areas were calculat-ed.VAH was determined as diameter of less than 2mm or an asymmetry ratio of noless than 1.7:1 of bilateral vertebral arter-ies.The patients were divided into VAH group or non-VAH group according to the above-mentioned definition.Differences in clinical data and PWI parameters of cerebellum and medulla oblongata were compared between the two groups.Difference would be considered statistically significant if P <0.05.Results:A total of 1 14 patients were admitted,including 57 males and 57 females.There are 31 cases (27.2%)in VAH group including 5 cases on the left side of vertebral artery and 26 cases on the right and 83 cases in non-VAH group.There were significant differences in the number of rTTP (P=0.005)or rCBF (P=0. 031 )of less than 85% between two groups.Significant difference tended to emerge in rCBF.No significant difference existed in rMTT or rCBV of ≤85%.Conclusions VAH could cause the hypo-perfusion of relevant territories of posterior inferior cerebel-lar artery,mainly predominating TTP extension and CBF reduction.