颅内椎基底动脉系统变异：CT血管造影研究

Variations in the intracranial velebmbasilar system： a CT angiography study

目的采用CT血管造影（CTangiography，CTA）评估颅内椎基底动脉的血管变异，提高对颅内椎基底动脉各种变异的认识。方法回顾性分析435例CTA图像，数据由16层螺旋CT扫描仪采集，全部图像经最大密度投影和容积再现技术处理，对颅内椎基底动脉进行测量分析。结果在435例受试者中，双侧椎动脉颅内段（V4）对称183例（42．07％），不对称252例（57．93％）；左侧V4段发育不良27例（6．21％），右侧36例（8．28％），共21例（4．83％）一侧v4段直接延续为同侧小脑后下动脉。椎基底动脉延长扩张2例（0．46％）。窗式变异32例（7．36％），其中v4段3例（0．69％），汇合处10例（2．30％），基底动脉19例（4．37％）。永存三又动脉2例（0．46％）。结论颅内椎基底动脉变异主要包括血管发育不良、椎基底动脉延长扩张、窗式变异以及永存三叉动脉。作为一种无创性血管成像方法，CTA可准确和直观地评估颅内椎基底动脉的解剖变异，为后颅窝手术的术前评估提供影像学指导。

Objective To evaluate the valuations of the intracranial vertebrobasilar arteries using CT angiography （CTA） in order to improve the understanding of various variants in intracranial vertebrobasilar arteries. Methods The CTA images of 435 subjects were analyzed retrospectively. The data were collected by a 16-shce CT scanner. All the CTA images were processed technically by the maximum intensity projection and volume rendering The intracranial vertebrobasilar arteries were measured and analyzed. Results Among the 435 subjects, bilateral intracranial vertebral arteries （V4） showed symmetry in 183 （42. 07%） and dissymmetry in 252 （57. 93%）. Hypoplasia were found in 27 subjects （6. 21%） on the left V4 segments and 36 （8.28%） on the right V4 segments, and a total of 21 （4. 83%） were directly continued as the ipsilateral posterior inferior cerebellar arteries on the unilateral V4 segments. There were 2 subjects （0. 46%） with vertebrobasilar dolichoectasia. There were 32 subjects （7. 36% ） had fenestration variation, 3 of them （0. 69% ） were on the V4 segments, 10 （2. 30%） at the junctions, and 19 （4. 37%） in the basilar arteries. Two subjects （0. 46%） had persistent trigeminal arteries. Conclusions The variations of intracranial vertebrobasilar arteries mainly include angiodysplasia, vertebrobasilar doliehoectasia, fenestration variation, and persistent trinninal artery. As a non- invasive vascular imaging method, CTA may accurately and visually assess the anatomic variation of intracranial vertebrobasilar artery, and provide imaging guidance for the preoperative evaluation of posterior fossa surest.