四维MR血管成像侧支循环分级在急性缺血性脑卒中患者近期疗效评估中的价值

The value of collateral circulation classification with 4-dimensional MR angiography in predicting the short-term outcome in patients with acute ischemic stroke

目的 探讨基于四维MRA的侧支循环分级评估急性缺血性脑卒中（AIS）患者近期疗效的可行性.方法 2013年3月至2017年3月前瞻性纳入47例单侧大脑中动脉（MCA）狭窄或闭塞的AIS患者,所有患者均在发病4.5～24.0 h内完成多模态MRI检查.采用灌注加权成像（PWI）原始图像创建MR动态血流图（4D-MRA）,并按照美国介入和治疗神经放射学学会/介入放射学学会（ASITN/SIR）制定的侧支循环分级系统对AIS患者进行侧支循环量化分级.根据美国国立卫生研究院卒中量表（NIHSS）评分改善情况将入组的AIS患者分为疗效显著组和无显著疗效组.统计两组间在基线资料、梗死体积、低灌注区与梗死区的体积比（rVPD）、侧支循环分级之间的差异,并以近期疗效是否显著作为因变量,进行logistic回归分析.采用Kappa系数分析观察者间侧支循环分级的一致性,采用Spearman秩相关系数分析侧支循环分级和梗死体积、低灌注区体积及rVPD等的相关性.结果 基于4D-MRA的侧支循环分级,47例患者中1级4例、2级21例、3级16例、4级6例.不同观察者之间的评分具有很高的一致性（Kappa=0.806,P〈0.01）.入组患者梗死体积中位数为29.63（4.92,69.17）ml,低灌注区体积为73.76（29.75,178.42）ml,rVPD为3.1（1.5,5.8）,侧支循环分级和入院时梗死体积呈明显负相关（r=-0.627,P〈0.01）,与低灌注区体积呈轻度负相关（r=-0.354,P〈0.01）,侧支循环分级和rVPD相关性较好（r=0.575,P〈0.01）.疗效显著组25例,无显著疗效组22例.两组在梗死体积、rVPD和侧支循环分级上差异具有统计学意义（P〈0.05）.logistic回归分析结果提示侧支循环分级是AIS患者是否具有显著疗效的独立预测因子（OR=4.419,P〈0.05）.结论 4D-MRA侧支循环分级评估脑组织动态血流变化可靠,是AIS患者临床疗效评估的独立预测因子.

Objective To assess the collateral grade based on 4-dimensional magnetic resonance angiography （4D-MRA） in predicting short-term outcome in patients with acute ischemic stroke （AIS）. Methods Forty-seven patients with unilateral MCA stroke were enrolled in this study. All patients underwent multi-modality MRI within 4.5 to 24.0 hours onset of stroke. The collateral grade was assessed through the dynamic MRI angiograms derived from perfusion raw data. The AIS patients were divided into favorable and unfavorable outcome group according to the improvement of national institutes of health stroke scale （NIHSS）score. The differences in baseline data, infarct volume, the ratio of volume of ischemic tissue on perfusion to infarct core on diffusion （rVPD）and collateral grade between the two groups were analyzed. Logistic regression analysis was used to identify variable influencing the short-term clinical outcomes. The Kappa coefficient was used to analyze the consistency of the collateral grade assessed between the two observers. Spearman rank-order correlation test was used to analyze the relationship between the collateral grade, infarct volume, hypoperfusion volume and rVPD. Results The collateral grade used ASITN/SIR based on 4D-MRA was pertormed in 47 patients. Grade 1 in 4 patients, grade 2 in 21paitients, grade 3 in 16 patients and grade 4 in 6 patients, respectively. The collateral grade had a high consistency among the observers （Kappa=0.806, P〈0.01）. Of the patients who enrolled the study, the median of infarct volume was 29.63 （4.92, 69.17） ml, the hypoperfusion volume was 73.76 （29.75,178.42） ml, and the rVPD was 3.1 （1.5, 5.8）. It was negatively correlated with initial infarct volume （r= - 0.627, P〈0.01） and hypoperfusion volume （ r= - 0.354, P〈0.01 ）. There was a significant positive correlation between the collateral grade and rVPD （r=0.575, P〈0.001）. There was also significant differences in infarct volume, rVPD, and collateral grade between favorable and mffavorable outcome group （P〈0.05）. The collateral grade based on 4D-MRA was an independent predictor of favorable clinical outcome （ OR=4.419, P〈0.05 ）. Conclusions The collateral circulation classification based on 4D-MRA proved to be a significant predictor of clinical outcome, it can be considered as a reliable method for analyzing the cerebral hemodynamie changes and collateral grade in AIS patients.