CT血管成像诊断颈动脉狭窄的可靠性

Carotid artery stenosis:reliability of CT angiography

目的评价CT血管成像(CTA)诊断颈动脉狭窄的可靠性。方法31例患者共62支颈动脉行MSCTA检查,两位研究者独立应用最大密度投影(MIP)、多平面重组(MPR)、容积再现(VR)及高级血管分析(AVA)进行重组,采用NASCET标准测量与评估血管狭窄程度。计算不同后处理方式研究者本身及研究者间的诊断相关性(r值)及一致性(K值)。并对可能影响颈动脉CTA可靠性的因素做进一步分析。结果①不同后处理方式均有较高的可靠性(P均<0.01),观察者本身的可靠性优于观察者间;②狭窄处血管腔形态(L/S)对VR观察者间的可靠性有显著影响(P<0.05);测量干扰因子对AVA观察者间的可靠性有显著影响(P<0.01);狭窄处直径测量差值对MIP及MPR观察者本身及观察者间、VR观察者间的可靠性有显著影响(P<0.05);参考点直径测量差值对AVA观察者本身及观察者间、MIP及VR观察者间的可靠性有显著影响(P<0.01)。结论CTA诊断颈动脉狭窄的可靠性较高。狭窄处直径测量、L/S、测量干扰因子及参考点的选择是影响其可靠性的主要因素。

Objective To assess the reliability of computed tomography angiography （CTA） in the evaluation of carotid artery stenosis. Methods Sixty-two vessels in 31 patients were evaluated with MSCTA. The stenosis were measured by two observers independently according to the NASCET criteria using multiple planar reformation （MPR）, maximum intensity projection （MIP）, volume rendering （VR） and advanced vessel analysis （AVA）. The intraobserver and interobserver correlation and agreement of different postprocessing techniques were estimated using r value and K value. A further analysis of the affecting factors was performed. Results ①There was excellent reliability for CTA of the assessment of carotid artery stenosis （P〈0.01）. Intraobserver reliability was superior to interobserver. ②L/S affected the interobserver reliability of VR （P〈0.05）. Interfering factor affects the interobserver reliability of AVA （P〈0.01）. The measurement of the stenosis level affected the intraobserver and interobserver reliability of MIP and MPR （P〈0.05） and the interobserver reliability of VR （P〈0.01）. The choice of reference level was the main affecting factor of the intraobserver and interobserver reliability of AVA （P〈0.01） and the interobserver reliability of MIP as well as that of MPR （P〈0.01）. Conclusion CTA of carotid artery is highly reproducible. The measurement of the stenosis level, L/S, interfering factor and the choice of reference level may affect the reliability of CTA.