RapidAI Compared With Human Readers of Acute Stroke Imaging for Detection of Intracranial Vessel Occlusion

Abstract

Rapid detection of intracranial arterial occlusion in patients with ischemic stroke is important to facilitate timely reperfusion therapy. We compared the diagnostic accuracy of neurologists and radiologists against RapidAI (iSchema View, Menlo Park, CA) software for occlusion detection. Adult patients who presented to a single comprehensive stroke center over a 5‐month interval with clinical suspicion of ischemic stroke and who underwent multimodality imaging with RapidAI interpretation were included. There were 8 assessors: 1 radiologist, 5 neurologists, and 2 radiology trainees. The reference standard was large‐vessel occlusion (LVO) or medium‐vessel occlusion (MVO) diagnosed by a panel of 4 interventional neuroradiologists. Positive likelihood ratio (LR) and negative LR were used to indicate how well readers correctly classified the presence of intracranial occlusions compared with the reference standard. The positive LR and negative LR for each reader were plotted on an LR graph using RapidAI LRs as comparator. The assessors read scans from 500 patients (49.6% men). The positive LR of RapidAI for detection of LVO was 8.49 (95% CI, 5.75–12.54), and the negative LR was 0.41 (95% CI, 0.28–0.58). The positive LR for LVO or MVO for RapidAI was 5.0 (95% CI, 3.28–7.63), and the negative LR was 0.66 (95% CI, 0.56−0.79). Sensitivity for LVO (0.65–0.96) and for LVO or MVO (0.62–0.94) was higher for all readers compared with RapidAI (0.62 and 0.39, respectively). Six of 8 readers had superior specificity to RapidAI for LVO (0.75–0.98 versus 0.93) and LVO or MVO (0.55–0.95 versus 0.92). Experienced readers of acute stroke imaging can identify LVOs and MVOs with higher accuracy than RapidAI software in a real‐world setting. The negative LR of RapidAI software was not sufficient to rule out LVO or MVO.