Prognosis with non-contrast CT and CT Perfusion imaging in thrombolysis-treated acute ischemic stroke

Abstract

Background and purpose: The Alberta Stroke Program Early CT Score (ASPECTS) and hyperdense vessel sign (HDVS) on baseline non-contrast CT (NCCT) may benefit prognosis of acute ischemic stroke (AIS). We aimed to investigate the agreement of ASPECTS between automated and manual interpretations, and further understand the roles of NCCT and CT Perfusion (CTP) in prognosis.

Materials and methods: From January 2019 to May 2020, thrombolysis-treated AIS patients undergoing NCCT and Perfusion imaging before treatment were retrospectively reviewed. A radiologist, a senior neuroradiologist and a neurologist blindly interpreted ASPECTS from NCCT images and a prototypical software produced automated results. Another independent radiologist determined presence of HDVS and CTP-ASPECTS. Three-month modified Rankin scale (mRS) ≤ 2 indicated good functional outcome. NCCT ASPECTS were compared against CTP-ASPECTS using squared weighted kappa. Univariable, multivariable and receiver operating characteristics (ROC) analysis were conducted to evaluate the prognostic value of clinical risk factors, NCCT and CTP findings.

Results: Seventy-five patients were included in this study, of whom 35 (46.7%) presented favorable outcome. Fair to substantial agreement with CTP-ASPECTS was witnessed for automated and manual interpretations (0.685, automated; 0.778, radiologist; 0.830, neuroradiologist; 0.313, neurologist). ASPECTS, HDVS, infarct core volume and mismatch ratio were univariably related to functional outcome, and infarct core volume remained as an independent prognostic factor in the multivariable analysis. The multivariable model achieved an area under ROC (AUC) of 0.768 (95% CI, 0.666-0.870).

Conclusions: Automated ASPECTS achieves substantial agreement with reference CTP-ASPECTS, and comprehensive CT assessment may benefit AIS prognosis after intravenous thrombolysis.

Keywords: ASPECTS; Computed tomography; HDVS; Perfusion imaging.