Fast automatic detection of large vessel occlusions on CT angiography

Abstract

Background and Purpose-Accurate and rapid detection of anterior circulation large vessel occlusion (LVO) is of paramountimportance in patients with acute stroke due to the potentially rapid infarction of at-risk tissue and the limited therapeuticwindow for endovascular clot retrieval. Hence, the optimal threshold of a new, fully automated software-based approachfor LVO detection was determined, and its diagnostic performance evaluated in a large cohort study.Methods-For this retrospective study, data were pooled from: 2 stroke trials, DEFUSE 2 (n=62; 07/08-09/11) andDEFUSE 3 (n=213; 05/17-05/18); a cohort of endovascular clot retrieval candidates (n=82; August 2, 2014-August 30,2015) and normals (n=111; June 6, 2017-January 28, 2019) from a single quaternary center; and code stroke patients(n=501; January 1, 2017-December 31, 2018) from a single regional hospital. All CTAs were assessed by the automatedalgorithm. Consensus reads by 2 neuroradiologists served as the reference standard. ROC analysis was used to assessdiagnostic performance of the algorithm for detection of (1) anterior circulation LVOs involving the intracranial internalcarotid artery or M1 segment middle cerebral artery (M1-MCA); (2) anterior circulation LVOs and proximal M2 segmentMCA (M2-MCA) occlusions; and (3) individual segment occlusions.Results-CTAs from 926 patients (median age 70 years, interquartile range: 58-80; 422 females) were analyzed. Threehundred ninety-five patients had an anterior circulation LVO or M2-MCA occlusion (National Institutes of Health StrokeScale 14 [median], interquartile range: 9-19). Sensitivity and specificity were 97% and 74%, respectively, for LVOdetection, and 95% and 79%, respectively, when M2 occlusions were included. On analysis by occlusion site, sensitivitieswere 90% (M2-MCA), 97% (M1-MCA), and 97% (intracranial internal carotid artery) with corresponding area-underthe-ROC-curves of 0.874 (M2), 0.962 (M1), and 0.997 (intracranial internal carotid artery).Conclusions-Intracranial anterior circulation LVOs and proximal M2 occlusions can be rapidly and reliably detected by anautomated detection tool, which may facilitate intra- and inter-instutional workflows and emergent imaging triage in thecare of patients with stroke.