Perfusion-based Collaterals in Prediction of Infarct Growth in Patients with Acute Ischemic Stroke: A Multicenter Comparative Analysis

BACKGROUND AND PURPOSE: In patients with acute ischemic stroke (AIS), robust collaterals are associated with lower rates of infarct growth. Perfusion-based collateral matrices including hypoperfusion intensity ratio (HIR), relative cerebral blood volume index (rCBV-Index), and perfusion collateral index (PCI) have been used successfully to assess collaterals in AIS patients. We aimed to assess and compare the diagnostic ability of these perfusion-based collateral indices in prediction of infarct growth in AIS patients following successful reperfusion. MATERIALS AND METHODS: multiplied by its corresponding mean rCBV) was calculated using Olea software (Olea Medical, SP.23). The association between perfusion-based collateral indices, along with demographic and clinical variables for determination of infarct growth was tested using appropriate univariate analysis. Multivariable logistic regression using a stepwise backward selection approach was performed to identify independent predictors of infarct growth. RESULTS: Among 116 included patients, 58 (50%) had infarct growth ≥10 mL. Infarct growth volume (median, IQR) was: 11, 2.6-34.7 mL. Poor collaterals determined by PCI and rCBV index was significantly (p<0.01) associated with infarct growth while HIR was not (p=0.83). Following multivariate logistic regression, three variables remained as independent predictors of infarct growth: baseline NIHSS (OR=1.10, 95%CI: 1.02-1.15, p=0.005); rCBV-Index (OR=0.005, 95%CI: 0.00-0.14, p=0.002); and PCI (OR=0.99, 95%CI: 0.98-0.99, p=0.01). CONCLUSIONS: Perfusion-based collateral indices that integrate CBV (rCBV-Index and PCI) outperformed delay-based HIR in prediction of substantial infarct growth in AIS patients and hence may play an important role in treatment decision-making, patient transfer decisions, and prognostication.