The Prognostic Value of a Four-Dimensional CT Angiography-Based Collateral Grading Scale for Reperfusion Therapy in Acute Ischemic Stroke Patients

ObjectiveLeptomeningeal collaterals, which affects tissue fate, are still challenging to assess. Four-dimensional CT angiography (4D CTA) originated from CT perfusion (CTP) provides the possibility of non-invasive and time-resolved assessment of leptomeningeal collateral flow. We sought to develop a comprehensive rating system to integrate the speed and extent of collateral flow on 4D CTA, and investigate its prognostic value for reperfusion therapy in acute ischemic stroke (AIS) patients.MethodsWe retrospectively studied 80 patients with M1 ± internal carotid artery (ICA) occlusion who had baseline CTP before intravenous thrombolysis. The velocity and extent of collaterals were evaluated by regional leptomeningeal collateral score on peak phase (rLMC-P) and temporally fused intensity projections (tMIP) (rLMC-M) on 4D CTA, respectively. The cutoffs of rLMC-P and rLMC-M score for predicting good outcome (mRS score ≤ 2) were integrated to develop the collateral grading scale (CGS) (rating from 0–2).ResultsThe CGS score was correlated with 3-months mRS score (non-recanalizers: ρ = -0.495, p = 0.01; recanalizers: ρ = -0.671, p p = 0.038, p = 0.018), while there was no significant difference in outcome in patients with poor collaterals (CGS score of 0) stratified by recanalization (p = 0.227).ConclusionsIdentification of collaterals based on CGS may help to select good responders to reperfusion therapy in patients with large artery occlusion.

影响组织转归的软脑膜侧支循环（leptomeningeal collaterals）目前仍难以准确评估。由CT灌注（CTP）衍生而来的四维CT血管造影（4D CTA），为无创且具备时间分辨能力的软脑膜侧支血流评估提供了可行途径。本研究旨在构建一套综合评分体系，整合4D CTA上侧支血流的流速与范围，并探讨其对急性缺血性脑卒中（acute ischemic stroke, AIS）患者再灌注治疗的预后价值。
方法 本研究回顾性纳入80例合并M1段±颈内动脉（internal carotid artery, ICA）闭塞的患者，所有受试者均在静脉溶栓前完成基线CTP检查。分别通过4D CTA峰值期区域软脑膜侧支评分（regional leptomeningeal collateral score on peak phase, rLMC-P）与时间融合强度投影（temporally fused intensity projections, tMIP）区域软脑膜侧支评分（rLMC-M），评估侧支循环的流速与覆盖范围。以预测良好预后（改良Rankin量表（modified Rankin Scale, mRS）评分≤2分）为目标，整合rLMC-P与rLMC-M的截断值，构建侧支循环分级量表（collateral grading scale, CGS），评分区间为0~2分。
结果 CGS评分与患者3个月时的mRS评分呈显著相关（未再通组：ρ=-0.495，p=0.01；再通组：ρ=-0.671，p p=0.038，p=0.018）；而对于侧支循环不良（CGS评分为0分）的患者，按再通状态分层后的预后差异无统计学意义（p=0.227）。
结论 基于CGS评估侧支循环，有助于筛选大动脉闭塞患者中可从再灌注治疗中获益的人群。