Evaluation Of Vertebral Artery Anomaly In Basilar Invagination:CTA Analysis

Objective:The objective of this study was to evaluate vertebral artery anomaly in patients with basilar invagination(BI)by Dual-source computed tomographic angiography(CTA)and to discuss how to use imaging examinations to guide the selection of surgical methods.Methods:This retrospective study had received institute review board approval with waiver of informed consent.This study included 28 patients with basilar invagination who underwent cervicocranial CTA examination,including 12 males and 16 females.150 normal subjects without any CVJ deformity were enrolled as normal control to evaluate the prevalence of vertebral artery anomaly in normal population,including 83 males and 67 females.In each patient,CTA was performed using a dual-source CT scanner with the following specific scanning parameters:140 kV,82 mAs;80 kV,164 mAs;the collimation was 64 × 0.6 mm;280 ms/rotation;pitch of 0.7.The primary axial,multiple planar reconstruction,volume-rendering and maximum intensity projection cervicocranial CTA images were analysed to evaluate vertebral artery anomaly at the CVJ.Observation and Measurements of vertebral artery were performed by two separate radiologists,and the data measured values are the average of the two measurements.Chi-square test was utilized for comparing the prevalence of vertebral artery anomaly between these two groups and the difference was statistically significant when P<0.05.Results:1?It shows no difference statistically in gender ratio of the two groups,P=0.224(P<0.05).2?Between the experimental group and the control group,it shows no difference statistically in the incidence of the original variations of vertebral artery,P=0.026(P<0.05).In the experimental group,the total incidence of variation in the origin of the vertebral artery was 14.3%(4/28).In the control group,the total incidence of variation in the origin of the vertebral artery was 2.7%(4/150).3?Between the experimental group and the control group,it shows no difference statistically in the incidence of the lateral vertebral artery hypoplasia(VAH),P=0.116(P<0.05).In the experimental group,the total incidence of the lateral vertebral artery hypoplasia was 42.9%(12/28).In the control group,the total incidence of the lateral vertebral artery hypoplasia was 28.0%(42/150).4?Between the experimental group and the control group,it shows no difference statistically in the incidence of persistent first intersegmental artery(PFIA),P=0.004(P<0.05).In the experimental group,the total incidence of persistent first intersegmental artery was 17.9%(5/28).In the control group,the total incidence of persistent first intersegmental artery was 2.7%(4/150).5?In the experimental group,the incidence of fenestrated vertebral artery(FEN)was 3.6%(1/28).In the control group,the incidence of fenestrated vertebral artery(FEN)was 0%(0/150).There was no effective statistical method to evaluate the incidence of fenestrated vertebral artery,because the deficient of the fenestrated vertebral artery in the control group.6?Between the experimental group and the control group,there was no statistically difference in the incidence of extracranial C1/2 origin of posterior inferior cerebellar artery,P=0.100(P<0.05).In the experimental group,the total incidence of extracranial C1/2 origin of posterior inferior cerebellar artery was 7.1%(2/28),In the control group,the total incidence of extracranial Cl/2 origin of posterior inferior cerebellar artery was 0.6%(1/150).7?Between the experimental group and the control group,there was statistically difference in the incidence of the total anomalous incidence of V3-4 segment of vertebral artery,P<0.001(P<0.05).In the experimental group,the incidence of the total anomalous incidence of V3-4 segment of vertebral artery was 28.6%(8/28).In the control group,the incidence of the total anomalous incidence of V3-4 segment of vertebral artery was 3.3%(5/150).8.Between the experimental group and the control group,there was statistical difference of the incidence of high riding vertebral artery(HRVA),P=0.001(P<0.05).In the experimental group,the incidence of the high riding vertebral artery was 35.7%(10/28).In the control group,the incidence of the high riding vertebral artery was 11.3%(17/150).Conclusion:Variation in the origin of the vertebral artery?the V3-4 segment of vertebral artery anomaly and high riding vertebral artery(HRVA)are more frequent in BI patients.And preoperative CT angiography(CTA)should be performed for this patient population.