The optimal methods for predicting early infarct growth rate (EIGR) in acute ischemic stroke with a large vessel occlusion (LVO) have not been established. We aimed to study the factors associated with EIGR, with a focus on the collateral circulation as assessed by the hypoperfusion intensity ratio (HIR) on perfusion imaging, and determine whether the associations found are consistent across imaging modalities.

Retrospective multicenter international study including patients with anterior circulation LVO-related acute stroke with witnessed stroke onset and baseline perfusion imaging (MRI or CT) performed within 24 hours from symptom onset. To avoid selection bias, patients were selected from (1) the prospective registries of 4 comprehensive stroke centers with systematic use of perfusion imaging and including both thrombectomy-treated and untreated patients and (2) 1 prospective thrombectomy study where perfusion imaging was acquired per protocol, but treatment decisions were made blinded to the results. EIGR was defined as infarct volume on baseline imaging divided by onset-to-imaging time and fast progressors as EIGR ≥10 mL/h. The HIR, defined as the proportion of time-to-maximum (Tmax) >6 second with Tmax >10 second volume, was measured on perfusion imaging using RAPID software. The factors independently associated with fast progression were studied using multivariable logistic regression models, with separate analyses for CT- and MRI-assessed patients.

Overall, 1,127 patients were included (CT, n = 471; MRI, n = 656). Median age was 74 years (interquartile range [IQR] 62–83), 52% were male, median NIH Stroke Scale was 16 (IQR 9–21), median HIR was 0.42 (IQR 0.26–0.58), and 415 (37%) were fast progressors. The HIR was the primary factor associated with fast progression, with very similar results across imaging modalities: The proportion of fast progressors was 4% in the first HIR quartile (i.e., excellent collaterals), ~15% in the second, ~50% in the third, and ~77% in the fourth (p < 0.001 for each imaging modality). Fast progression was independently associated with poor 3-month functional outcome in both the CT and MRI cohorts (p < 0.001 and p = 0.030, respectively).

The HIR is the primary factor associated with fast infarct progression, regardless of imaging modality. These results have implication for neuroprotection trial design, as well as informing triage decisions at primary stroke centers.

尚未建立预测伴有大血管闭塞（LVO）的急性缺血性卒中早期梗塞生长率（EIGR）的最佳方法。我们的目的是研究与 EIGR 相关的因素，重点关注通过灌注成像的低灌注强度比 (HIR) 评估的侧支循环，并确定所发现的关联在不同成像模式中是否一致。

回顾性多中心国际研究，包括患有前循环 LVO 相关急性卒中的患者，这些患者目睹了卒中发作，并在症状出现后 24 小时内进行了基线灌注成像（MRI 或 CT）。为了避免选择偏倚，患者选自（1）系统使用灌注成像的 4 个综合性卒中中心的前瞻性登记，包括接受血栓切除术治疗和未治疗的患者，以及（2）1 项前瞻性血栓切除术研究，其中按照方案采集灌注成像，但治疗决策是在对结果视而不见的情况下做出的。EIGR 定义为基线成像的梗死体积除以发病到成像时间和快速进展（EIGR ≥10 mL/h）。HIR 定义为最大时间 (Tmax) > 6 秒与 Tmax > 10 秒体积的比例，使用 RAPID 软件在灌注成像上进行测量。使用多变量逻辑回归模型研究与快速进展独立相关的因素，并对 CT 和 MRI 评估的患者进行单独分析。

总体而言，纳入了 1,127 名患者（CT，n = 471；MRI，n = 656）。中位年龄为 74 岁（四分位距 [IQR] 62-83），52% 为男性，NIH 卒中量表中位为 16（IQR 9-21），中位 HIR 为 0.42（IQR 0.26-0.58），415 岁（37%） ）是快速进步者。HIR 是与快速进展相关的主要因素，不同成像方式的结果非常相似：快速进展者的比例在第一个 HIR 四分位数（即优秀的侧支循环）中为 4%，在第二个四分位数中约为 15%，在第二个四分位数中约为 50%。第三个，第四个约 77%（每种成像方式p < 0.001）。在 CT 和 MRI 队列中，快速进展与 3 个月功能结果不佳独立相关（分别为p < 0.001 和p = 0.030）。

无论成像方式如何，HIR 都是与梗塞快速进展相关的主要因素。这些结果对神经保护试验设计具有重要意义，并为初级卒中中心的分诊决策提供信息。