4D-CTA评估急性缺血性脑卒中患者侧支循环与CTP灌注参数的相关性

4D-CTA Assessment of the Correlation between Collateral Circulation and CT Perfusion Parameters in Patients with Acute Ischemic Stroke

目的应用4D-CTA技术评估急性缺血性脑卒中患者的侧支循环状态与脑灌注参数的相关性,探讨其与最终梗死体积的关系。方法搜集本院41例单侧大脑中动脉或颈内动脉闭塞患者临床及影像资料,所有患者于发病6 h内行头颈CT平扫、头颅CT灌注成像(CTP)检查及常规头颈CTA检查。基于4D-CTA采用改良ASITN/SIR侧支循环评分法评估侧支循环,利用后处理工作站处理CTP图像,获得灌注参数(rCBV、rCBF、rMTT、Tmax及HIR)。采用Spearman秩相关分析改良ASITN/SIR侧支循环评分与入院时基线核心梗死区体积、低灌注体积、严重低灌注体积及核心梗死区与低灌注区不匹配比及最终梗死体积的相关性。基于4D-CTA的ASITN/SIR侧支循环评分将患者分为侧支循环良好组及侧支不良组,采用Mann-Whiney U检验或χ~2检验比较两组间基线临床及影像学参数差异性。采用多因素二元Logistic回归法分析CTP各参数与侧支循环的关系并用受试者工作特征曲线(ROC)评价其在预测侧支循环的价值。结果基于4D-CTA的侧支循环分级,41例患者中0级3例,1级2例,2级8例,3级4例,4级24例,ASITN/SIR侧支循环评分与入院时基线梗死体积呈明显负相关(Spearman’s rho=-0.80,P<0.01),与低灌注区的体积呈中度负相关(Spearman’s rho=-0.57,P<0.01),与严重低灌注体积(Tmax>12s)呈明显负相关(Spearman’s rho=-0.74,P<0.01),与核心梗死体积与低灌注不匹配比呈中度相关(Spearman’s rho=0.64,P<0.01)。侧支循环评分与最终梗死体积呈明显负相关(Spearman’s rho=-0.85,P<0.01)。侧支循环良好组与不良组间rCBV、rCBF、Tmax及HIR差异具有统计学意义。Logistic回归分析显示rCBV、rCBF、Tmax及HIR可反映侧支循环状态,其中rCBV及HIR的ROC曲线下面积较rCBF、Tmax大。结论脑血流灌注参数rCBV及低灌注指数HIR可优先提示急性缺血性脑卒中患者侧支循环状态,良好的侧支循环状态有助于预测较小的最终梗死体积。

Objective To evaluate the correlation between collateral circulation status and cerebral perfusion parameters in patients with acute ischemic stroke by 4 D-CTA technique,and to explore its relationship with final infarct volume.Methods Clinical and imaging data of 41 patients with unilateral middle cerebral artery or internal carotid artery occlusion were collected.All patients underwent CT scan of head,CT perfusion imaging(CTP)and routine head and neck CTA examination within 6 hours after onset.The collateral circulation was evaluated based on 4 D-CTA using the modified ASITN/SIR collateral circulation scoring method,and the CT perfusion images were processed by the post-processing workstation to obtain perfusion parameters(rCBV,rCBF,rMTT,Tmax and HIR).Spearman rank correlation analysis was used to improve the correlation between ASITN/SIR collateral circulation score and baseline core infarct volume,low perfusion volume,severe hypoperfusion volume,and the mismatch ratio of the core infarct and low perfusion,and final infarct volume.The ASITN/SIR collateral circulation score based on 4 D-CTA was divided into patients with good collateral circulation and poor collaterals.The Mann-Whiney U test orχ~2 test was used to compare the clinical and imaging parameters between the two groups.Multivariate binary logistic regression was used to analyze the relationship between CTP parameters and collateral circulation and to evaluate the value of predicting collateral circulation using receiver operating characteristic curve(ROC).Results The collateral grade used ASITN/SIR based on 4 D-CTA was performed in 41 patients.Grade 0 in 3 patients,grade 1 in 2 patients,grade 2 in 8 patients,grade 3 in 4 patients and grade 4 in 24 patients.1.The ASITN/SIR collateral circulation grade was significantly negatively correlated with baseline infarct volume at admission(Spearman’s rho=-0.80,P<0.01),moderately negatively correlated with the volume of the low perfusion area(Spearman’s rho=-0.57,P<0.01),and was significantly negatively correlated with severe hypoperfusion volume(Tmax>12 s)(Spearman’s rho=-0.74,P<0.01).The ratio of core infarct volume to low perfusion mismatch was moderately correlated with collateral circulation grade(Spearman’s rho=0.64,P<0.01).There was a significant negative correlation between collateral circulation and final infarct volume(Spearman’s rho=-0.85,P<0.01).The differences of rCBV,rCBF,Tmax and HIR between the good collateral circulation group and the poor group were statistically significant.RCBV,rCBF,Tmax and HIR can indicate the state of collateral circulation,in which the area under the ROC curve of rCBV is the largest.Conclusion Cerebral blood perfusion parameters rCBV and hypoperfusion index(HIR)can preferentially suggest collateral circulation in patients with acute ischemic stroke.Good collateral circulation status can help predict a smaller final infarct volume.