Objective To evaluate the diagnostic value of multi-slice three-dimensional computed tomographic angiography(MS 3D-CTA)for vertebrobasilar dolichoectasia(VBD).Methods MS 3D-CTA of 10 patients with VBD were retrospectively analysed.Source images were got by GE Lightspeed pro scanner.Volume rendering(VR)and maximum intensity project (MIP) were adopted to reconstruct 3D images in all cases.Twenty patients were selected as the control group by suspected cerebra[vascular diseases and underwent MS 3D-CTA at the same period.Enumeration data between the patient group and the control group was assessed by Wilcoxon.test.Results There were 2 types of 10 cases with VBD,including simple type(n=4)and saddle type(n=6).Compared with the control group of the length of the basilar artery(B 1,25.60 mm),the deviant degree(Bc,1.20 mm),the height(Bh,1.90 am),the length of the vertebral artery (V1,17.55 mm),the deviant degree(Vc,2.05 mm),and the diameter of BA and/or VA (Bw/Vw,3.05 mm),there is significant difference in the B1 30.20 mm,Bc 7.10 mm,Bh 8.80 mm,V1 23.00 mm,Vc 5.95 mm,and Bw/Vw 5.05 mm(P＜0.01,all).Conclusion The clinical performances of VBD is different,MS 3D-CTA is a very effective method for the diagnosis of VBD.