多模式CT检查在缺血性脑卒中侧支循环评估中的价值

The value of multimodal CT in assessment of collateral circulation in ischemic stroke

目的:探讨缺血性脑卒中侧支循环形成的影响因素及多模式CT对侧支循环的评估价值。方法:搜集本院42例急性缺血性脑卒中患者的病例资料,发病3天内及7天内分别行多模式CT及数字减影血管造影(DSA)检查。CTA数据经最大密度投影法(MIP)、容积再现法(VR)重建评价一级侧支循环,多时相CTA评价二级侧支循环,CTP数据经软件后处理得到相对脑血流量(rCBF)、相对脑血容量(rCBV)、相对平均通过时间(rMTT)及相对达峰时间(rTTP)4个参数。以DSA检查为金标准,一级侧支循环分为变异组和完整组,二级侧支循环分为良好组(3,4级)、一般组(1,2级)和很差组(0级),采用Kappa检验、McNemar检验及Spearman相关性分析分别评价多模式CT对一级及二级侧支循环的诊断效能。结果:42例缺血性脑卒中患者的临床特征中,高血压、糖尿病、责任血管重度狭窄在良好侧支循环组与不良侧支循环组间差异有统计学意义(P<0.05),其中仅高血压和责任血管重度狭窄与侧支循环形成有相关性。CTA对一级侧支循环显示的敏感度为96.0%,特异度为100%,阳性预测值为100%,阴性预测值为94.4%,准确度为97.6%;CTA对二级侧支循环显示的敏感度为100.0%,特异度为88.9%,阳性预测值为92.3%,阴性预测值为100.0%,准确度为95.2%。DSA与CTA两种检查方法的诊断效能差异无统计学意义(P=1.000),两种检查方法间的Kappa值为0.951,表示两种方法的一致性很好。DSA与多期CTA对二级侧支循环的检查结果:两种检查方法的诊断效能差异无统计学意义(P=0.311),两种检查方法间的Kappa值为0.817,表示两种方法的一致性很好。CTP的4个参数中rCBV、rMTT与二级侧支循环有相关性,其中rCBV的相关性最好(r=0.731,P<0.05)。结论:多模式CT能显示侧支循环的血管结构及灌注信息,与DSA有很好的一致性,可作为临床诊断及评估缺血性脑卒中预后的可靠影像学检查手段。

Objective:To investigate the influencing factors of collateral circulation formation in ischemic stroke and the value of multimodal CT in evaluating collateral circulation.Methods:The clinical data of 42 patients with acute ischemic stroke were collected in our hospital.Multimodal CT and digital subtraction angiography(DSA)were performed within 7 days after onset,respectively.CTA data were reconstructed by maximum density projection(MIP)and volume rendering(VR)to evaluate the primary and the secondary collateral circulation.CTP data were processed by software to obtain four parameters:relative cerebral blood flow(rCBF),relative cerebral blood volume(rCBV),relative mean transit time(rMTT)and relative peak time(rTTP).DSA examination as the gold standard,the primary collateral circulation was divided into the variant group and the complete group,and the secondary collateral circulation was divided into good group(grade 3,4),fair group(grade 1,2)and poor group(grade 0).Kappa test,McNemar test and Spearman correlation analysis were used to evaluate the diagnostic performance of multimodal CT for the primary and secondary collateral circulation,respectively.Results:Among the clinical characteristics of 42 patients with ischemic stroke,there were statistically significant differences in hypertension,diabetes and severe stenosis of the responsible vessel between the group of good collateral circulation and the group of poor collateral circulation(P<0.05),only hypertension and severe stenosis of the responsible vessel correlated with collateral circulation formation.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of CTA for the display of primary collateral circulation were 96.0%,100%,100%,94.4%and 97.6%,respectively;the above diagnostic performance of CTA for secondary collateral circulation were 100.0%,88.9%,92.3%,100.0%and 95.2%,respectively.There was good consistency between DSA and CTA on displaying the primary and secondary collateral circulation(Kappa=0.951,P=1.000;Kappa=0.817,P=0.311,respectively).Among the four parameters of CTP,rCBV and rMTT were correlated with secondary collateral circulation,among which rCBV had the best correlation(r=0.731,P<0.05).Conclusions:Multimodal CT can display the vessel structure and perfusion information of collateral circulation,which has good consistency with DSA,and can be used as a reliable imaging examination for clinical diagnosis of ischemic stroke and its prognosis evaluation.