The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is an established 10-point quantitative topographic computed tomography scan score to assess early ischemic changes. We performed a non-inferiority trial between the e-ASPECTS software and neuroradiologists in scoring ASPECTS on non-contrast enhanced computed tomography images of acute ischemic stroke patients. In this multicenter study, e-ASPECTS and three independent neuroradiologists retrospectively and blindly assessed baseline non-contrast enhanced computed tomography images of 132 patients with acute anterior circulation ischemic stroke. Follow-up scans served as ground truth to determine the definite area of infarction. Sensitivity, specificity, and accuracy for region- and score-based analysis, receiver-operating characteristic curves, Bland-Altman plots and Matthews correlation coefficients relative to the ground truth were calculated and comparisons were made between neuroradiologists and different pre-specified e-ASPECTS operating points. The non-inferiority margin was set to 10% for both sensitivity and specificity on region-based analysis. In total 2640 (132 patients × 20 regions per patient) ASPECTS regions were scored. Mean time from onset to baseline computed tomography was 146 ± 124 min and median NIH Stroke Scale (NIHSS) was 11 (6–17, interquartile range). Median ASPECTS for ground truth on follow-up imaging was 8 (6.5–9, interquartile range). In the region-based analysis, two e-ASPECTS operating points (sensitivity, specificity, and accuracy of 44%, 93%, 87% and 44%, 91%, 85%) were statistically non-inferior to all three neuroradiologists (all p-values <0.003). Both Matthews correlation coefficients for e-ASPECTS were higher (0.36 and 0.34) than those of all neuroradiologists (0.32, 0.31, and 0.3). e-ASPECTS was non-inferior to three neuroradiologists in scoring ASPECTS on non-contrast enhanced computed tomography images of acute stroke patients.

Validation of automatically derived acute ischemic volumes (AAIV) from e-ASPECTS on non-contrast computed tomography (NCCT). Data from three studies were reanalyzed with e-ASPECTS Version 7. AAIV was calculated in milliliters (ml) in all scored ASPECTS regions of the hemisphere detected by e-ASPECTS. The National Institute of Health Stroke Scale (NIHSS) determined stroke severity at baseline and clinical outcome was measured with the modified Rankin Scale (mRS) between 45 and 120 days. Spearman ranked correlation coefficients (R) of AAIV and e-ASPECTS scores with NIHSS and mRS as well as Pearson correlation of AAIV with diffusion-weighted imaging and CT perfusion-estimated ischemic “core” volumes were calculated. Multivariate regression analysis (odds ratio, OR with 95% confidence intervals, CI) and Bland–Altman plots were performed. We included 388 patients. Mean AAIV was 11.6 ± 18.9 ml and e-ASPECTS was 9 (8–10: median and interquartile range). AAIV, respectively e-ASPECTS correlated with NIHSS at baseline (R = 0.35, p < 0.001; R = −0.36, p < 0.001) and follow-up mRS (R = 0.29, p < 0.001; R = −0.3, p < 0.001). In subsets of patients, AAIV correlated strongly with diffusion-weighted imaging (n = 37, R = 0.68, p < 0.001) and computed tomography perfusion-derived ischemic “core” (n = 41, R = 0.76, p < 0.001) lesion volume and Bland–Altman plots showed a bias close to zero (−2.65 ml for diffusion-weighted imaging and 0.45 ml forcomputed tomography perfusion “core”). Within the whole cohort, the AAIV (OR 0.98 per ml, 95% CI 0.96–0.99) and e-ASPECTS scores (OR 1.3, 95%CI 1.07–1.57) were independent predictors of good outcome AAIV on NCCT correlated moderately with clinical severity but strongly with diffusion-weighted imaging lesion and computed tomography perfusion ischemic “core” volumes and predicted clinical outcome.

Background: An ambulance equipped with a computed tomography (CT) scanner, a point-of-care laboratory, and telemedicine capabilities (mobile stroke unit [MSU]) has been shown to enable the delivery of thrombolysis to stroke patients directly at the emergency site, thereby significantly decreasing time to treatment. However, work-up in an MSU that includes CT angiography (CTA) may also potentially facilitate triage of patients directly to the appropriate target hospital and specialized treatment, according to their individual vascular pathology. Methods: Our institution manages a program investigating the prehospital management of patients with suspicion of acute stroke. Here, we report a range of scenarios in which prehospital CTA could be relevant in triaging patients to the appropriate target hospital and to the individually required treatment. Results: Prehospital CTA by use of an MSU allowed to detect large vessel occlusion of the middle cerebral artery in one patient with ischemic stroke and occlusion of the basilar artery in another, thereby allowing rational triage to comprehensive stroke centers for immediate intra-arterial treatment. In complementary cases, prehospital imaging not only allowed diagnosis of parenchymal hemorrhage with a spot sign indicating ongoing bleeding in one patient and of subarachnoid hemorrhage in another but also clarified the underlying vascular pathology, which was relevant for subsequent triage decisions. Conclusion: Defining the vascular pathology by CTA directly at the emergency site may be beneficial in triaging patients with various cerebrovascular diseases to the most appropriate target hospital and specialized treatment.