PWI联合MRA评价椎基底动脉狭窄所致的后循环远端无症状缺血

Perfusion-Weighted Imagining Combined with MRA Evaluation of Asymptomatic Cerebral Ischemia in the Posterior Circulation Distal Area,Caused by Stenosis of Vertebral Artery and Basilar Artery

目的探讨利用PWI联合MRA技术评价椎基底动脉狭窄所致后循环远端的无症状型缺血情况。方法设立3组研究对象。A组:无症状组(n=22);B组:症状组(n=22);C组:健康对照组(n=30)。分析3组PWI和MRA检查资料,观察后循环血管狭窄程度,侧支血管分级的显示,局部脑血流量(r CBF)、局部脑血容量(r CBV)、平均通过时间(r MTT)指标。结果 3组研究对象前后循环血管的MRA图像均取得满意效果;A、B、C 3组后交通动脉开放的比率分别为68.2%(15/22)、77.3%(17/22)、50%(15/30),软脑膜动脉生成的比率分别为31.8%(7/22)、59.1%(13/22)、23.3%(7/30);A组与C组比较,r CBF、MTT存在差异,r BCV无明显差异;A组与B比较,B组的r CBF、r BCV下降,MTT延长,存在统计学差异。结论 PWI联合MRA,能够评价无症状型后循环缺血的范围及侧支循环血流,可以尽早地为临床提示后循环血液动力学状况,为治疗及评价预后提供帮助。

Objective To evaluate silent cerebral ischemia in the posterior circulation distal area that has been as a result of stenosis of the vertebral or basilar artery,with PWI and MRA Methods Three groups of patients were set up.Among them,cases with stenosis of vertebral or basilar artery in Group A showed no ischemia.Cases with stenosis of vertebral or basilar artery in Group B showed ischemia.Cases in Group C were healthy people.Using PWI and MRA,observe the degree of stenosis of the concerned artery in the posterior circulation area,the display of collateral vessels,classification and state of the collaterals,regional cerebral blood flow（rC BF）,regional cerebral blood volume（rC BV）,and regional mean transit time（rM TT）.We then collected related information and data and analyzed these data in three groups.Results The MRA images of all the three groups were reliable.The ratios of the open Posterior communicating artery were 15（68.1%）,17（77.2%） and 15（50%）,respectively.The ratios of display of soft meningeal arteries were 7（31.8%）,13（59.0%）,7（23.3%）,respectively.It was found that there was a difference in the rC BF and MTT between Group A and Group C,but no obvious difference in rC BV.Comparing Group A and B,we found that the rC BF and rB CV in Group B were lower and the MTT value in Group B was lengthened,which showed no statistical difference.Conclusion PWI combined with MRA,can efficiently evaluate silent cerebral ischemia in the posterior circulation distal area caused by stenosis of the vertebral or basilar artery and offers great help in clinical treatment and in evaluating silent cerebral ischemia.