Computed Tomographic Perfusion Imaging Variables Versus Time From Stroke Onset to Acute Reperfusion Therapy in Predicting Functional Outcome

Background The rate of infarct growth from a yet salvageable penumbra into an ischemic core varies between individuals. Thus, computed tomographic perfusion (CTP) may improve patient selection for intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT). We aimed to assess whether treatment delay and pretreatment CTP parameters are independent predictors of functional outcome. Materials and Methods Consecutive patients who underwent CTP and received reperfusion therapy with a known stroke onset were identified retrospectively at Helsinki University Hospital between 1/2016 and 12/2023. Ordinal regression was used to analyze the association between the CTP parameters estimated by RAPID, an automated CTP postprocessing software, and onset‐to‐treatment time with an unfavorable shift on the 3‐month modified Rankin Scale (mRS) in the entire cohort, in IVT‐only patients, and in EVT patients with or without reperfusion. Results In the univariable analyses of the total of 948 patients, increasing onset‐to‐treatment time (odds ratio 1.17, 95% confidence interval 1.11–1.25), ischemic core (12.5, 8.33–20.0), and penumbra (2.27, 1.89–2.70) volumes were associated with worse outcomes. In the multivariable analyses, ischemic core volume (4.76, 2.94–7.69) and onset‐to‐treatment time (1.20, 1.14–1.28) were significant predictors of worse outcomes, but not baseline penumbra volume (1.06, 0.86–1.30), which was compatible in IVT‐only patients and in EVT patients with reperfusion. Also, larger severe hypoperfusion volume, higher hypoperfusion intensity ratio, and cerebral blood volume index were associated with functional outcomes in the total cohort. Conclusions Both ischemic core and penumbra volumes and onset‐to‐treatment time predicted a worse outcome, but of these, only ischemic core and onset‐to‐treatment time were independent predictors.