目的以DSA为诊断金标准， 探讨CTA、MRA在老年人后循环缺血 (posterior circulation ischemia,PCI) 病因中的诊断价值及优缺点。方法 回顾 性分析经DSA确诊为后循环缺血的35例患 者的脑MRA及CTA图像，并计算两种血管 成像方法对病因诊断准确性。结果 35例 患者共113支血管病变，病变分别位于椎 动脉(49.6% 56/113)、基底动脉(23.0% 26/113)、大脑后动脉(27.4% 31/113)。 MRA、CTA对病变血管的诊断准确率分别 为77.0%、86.7%，与DSA对比，MRA对老 年后循环缺血病因的Kappa值为0.70； CTA对老年后循环缺血病因的Kappa值为 0.82。结论 与MRA相比，CTA在诊断后循 环血管狭窄和闭塞具有更高的准确性， 可作为诊断PCI病因的可靠手段。

Objective To study the value of CT angiography(CTA) and magnetic resonance angiography(MRA) in the diagnosis of the etiology of the elderly posterior circulation ischemia, compared with digital subtraction angiography(DSA). Methods A retro spective analysis of 35 patients diagnosed posterior circulation ischemic were checked by MRA and CTA.The locations of the lesions shown by various imaging techniques were analyzed and the diagnostic accuracy was calculated. Results A total of 113 diseased vessel segments were identified by DSA. After consensus interpretation, the lesions were located in the vertebral artery(49.6% 56/113), basilar artery(23.0% 26/113), posterior cerebral artery (27.4% 31/113).The diagnostic accuracy of MRA, CTA was 77.0%, 86.7% respectively. Compared with DSA, the Kappa value was 0.70, 0.82 for the diagnosis of the etiology of the elderly posterior circulation ischemia. Conclusions CTA has a higher accuracy than MRA and is recommended over TOF MRA for detection of posterior circulation ischemia.CTA results had a significant effect on patient clinical management.