双源64层CT在椎动脉狭窄诊断中的价值

目的 评价双源64层CT血管造影(CTA)在椎动脉狭窄诊断中的价值.方法 后循环脑缺血症状患者61例,均同时接受数字减影血管造影术(DSA)与CTA检查;使用双源64层CT进行扫描,运用最大密度投影(MIP)、多平面重组(MPR)、曲面重组(CPR)、和容积再现(VR)技术进行重组和轴位像放大以精确测量狭窄血管和正常血管的直径;采用北美症状性颈动脉内膜切除实验(North American Symptomatic Carotid Endarterectomy Trial,NASCET)方法进行血管狭窄程度分级,CTA和DSA检查结果分别由2名高年资放射科医生进行测量.结果经CTA和DSA检查的122支血管中,共有100支具有一致性;狭窄率≥70%时,CTA的敏感度96.4%,特异度96.8%,阳性预测值90.0%,阴性预测值98.9%;≥50%时,CTA的敏感度97.9%,特异度89.2%,阳性预测值85.5%,阴性预测值98.5%,CTA与DSA的狭窄率有很高的相关性(r=0.98,P<0.01).结论 CTA在诊断椎动脉狭窄程度上与DSA有很高的相关性,可作为椎动脉狭窄筛选的常规检查手段.

Application of dual source 64-slice CT angiography in evaluating internal vertebral artery stenosis

Objective To evaluate the diagnostic accuracy of dual source 64-slice computer tomographyic angiography(CTA) for internal vertebral artery stenosis.Methods Sixty-one posterior circulation stroke or TIA patients with interpretable CTA and digital subtraction angiography(DSA) of the vertebral arteries were selected.In CTA,the grade of stenosis was determined using axial source,maximum intensity projection(MIP),multi-plane reconstruction(MPR) as well as volume rendering(VR) images.The images were blindly analyzed by two neuroradiologists using the North American Symptomatic Carotid Endarterectomy trial(NASCET) criteria separately.Results CTA agreed with DSA categorization of a stenosis in 100 of the 122 arteries.When 70% stenosis was used as the cut-off value,the sensitivity,specificity,negative predictive value and the positive predicting value were 96.4%,96.8%,98.9% and 90.0%,respectively.When 50% stenosis was used as the cut-off value,the sensitivity,specificity,negative predictive value and the positive predicting value were 97.9%,89.2%,98.5% and 85.5%,respectively.Degree of artery stenosis on CTA closely correlated with that on DSA(r=0.98,P<0.01).Conclusion An excellent correlation and high accuracy were demonstrated between CTA and DSA on degree of stenosis,thus CTA appears to be an excellent screening test for vertebral artery stenosis.