轴位T2加权MRI流空现象在VBA诊断中的价值

Value of Absence of Flow Void Phenomena on Axial T2-Weighted MRI in the Diagnosis of Vertebrobasilar Artery

目的:本研究旨在识别轴位MRI-T2W流空信号消失,在评估后循环急性缺血性患者椎-基底动脉重度狭窄或闭塞的临床意义。方法:入组急性缺血性卒中住院患者,DWI显示为后循环血管供血区域急性梗死患者,由两名放射科医师判断椎-基底动脉流空信号是否消失。以CTA为金标准,评估轴位MRI-T2W流空信号消失诊断椎-基底动脉重度狭窄或闭塞的准确性。结果:我院神经内科2012年11月至2013年11月期间,符合纳入及排除标准的80例后循环梗死患者中,轴位T2加权MRI显示椎-基底动脉流空信号消失20例、正常60例;轴位T2显示流空信号消失20例中,CTA显示椎-基底动脉重度狭窄或闭塞18例(真阳性率90%)、正常2例(假阳性率10%);T2流空信号正常的60例中,CTA显示,重度狭窄或闭塞2例(假阴性率3.3%),正常58例(真阴性率96.7%)。结论:轴位MRI-T2加权像显示椎-基底动脉流空信号消失,在很大程度上可确定其存在重度狭窄或闭塞,为进行迅速诊断和针对性治疗提供依据。

Objective:To identify the absence of flow void phenomenon(AFVP)on axial T2-weighted magnetic resonance imaging(MRI)(T2WI)and its clinical significance for evaluating the severe stenosis or occlusion of vertebralbasilar artery(VBA)in the patients with acute ischemic stroke of posterior circulation(AIS-PC).Methods:The consecutive patients with clinical diagnosis of acute ischemic stroke were enrolled.In those with acute infarction within blood supply area of posterior circulation shown by Diffusion Weighted Imaging(DWI)(i.e.abnormal high signals),two neuro-radiologists judged whether AFVP of VBA on axial T2WI;then we evaluated the diagnostic accuracy of AFVP for severe stenosis or occlusion of VBA using the results of computed tomography angiography(CTA)as a standard.Results:In our hospital from November 2012 to November 2013,80AIS-PC patients who were conformed to our flow void signal of VBA on axial T2 WI findings.Among 20 patients with AFVP of VBA on axial T2 WI,CTA showed VBA stenosis or occlusion in 18 and normal finding in 2cases,in which the true positive rate was 90%;a-mong 60 patients with normal flow void signal of VBA on axial T2 WI,CTA showed normal findings in 58 and stenosis or occlusion of VBA in 2cases,in which the true negative rate was96.7%.Conclusion:For patients with posterior circulation stroke,VBA severe stenosis or occlusion could largely be determined according to AFVP on axial T2 WI,which may provide evidences for rapid diagnosis and targeted therapy.