灌注磁共振结合脑血管造影评估短暂性脑缺血发作

Evaluation of transient ischemic attack using perfusion MRI and DSA

目的研究颈动脉系统短暂性脑缺血发作(transient ischemic attack,TIA)患者经灌注磁共振(PWI)后的改变与颈动脉狭窄的相关性。方法对49例颈内动脉系统TIA行全脑数字减影血管造影(DSA)及PWI检查,根据颈动脉狭窄程度分为轻度狭窄组(8例)、中度狭窄组(11例)、重度狭窄组(21例)、极重度狭窄组(9例)。研究颈内动脉狭窄程度、局部脑血流量(rCBF)和达峰时间(TTP)。结果4组患者间rCBF和同组患侧rCBF与对侧rCBF比较,差异均无统计学意义(P>0.05),中度狭窄组、重度狭窄组和极重度狭窄组患侧TTP与对侧TTP比较,差异有统计学意义(P<0.01),重度狭窄组和极重度狭窄组的TTP分别较轻度狭窄组和中度狭窄组明显延迟(P<0.05)。随着脑动脉狭窄程度的加重,患侧TTP呈线性增加趋势(P<0.05)。结论DSA可以对颈动脉狭窄程度做出准确评价,PWI在评价脑循环的血流动力变化方面有重要的作用,其中TTP较rCBF对颈动脉狭窄引起的缺血性改变更为敏感。

Objective To investigate the correlation between MRI-PWI changes and the degree of carotid artery stenosis in transient ischemic attack（TIA） patients. Methods Forty-nlne patients with TIAs were divided into 4 groups according to degree of carotid stenosis：mild stenosis group, moderate stenosis group,severe stenosis group and very severe stenosis group. They were evaluated with digital subtraction angiography（DSA）and perfusion weighted imaging（PWI）,including internal carotid artery stenosis degree by DSA, regional cerebral blood flow（rCBF） and time to peak（TTP） by MRI-PWI. Results rCBF had no significant difference between four groups and between stenosis side and opposite side （P 〉 0.05） ,but TTP in the severe stenosis and very severe stenosis groups was significantly longer than that in normal and moderate stenosis groups （P 〈 0.05）. Conclusion DSA can precisely evaluate degree of carotid stenosis,and PWI plays an important role in evaluating hemodynamic change of TIA. TTP is a more sensitive marker for TIA caused by carotid artery system stenosis than rCBF.