Purpose: Detection of intracranial arterial occlusions on CT angiography (CTA) can be challenging. We studied the value of CT perfusion (CTP) for arterial occlusion detection in the anterior circulation amongst radiologists and neurologists, both experienced and less experienced.
Methods: Seven raters reviewed CTAs of 335 acute stroke patients with and without occlusions. We evaluated occlusion detection with and without CTP. We categorized the occlusions by location. Two experienced raters exposed to all baseline and follow-up imaging defined a consensus gold standard. We calculated sensitivity, specificity and accuracy for occlusion detection with and without CTP and compared the area under the curve (AUC). We also compared the performance of radiologists versus neurologists and of experienced and less experienced raters.
Results: We included 260 patients with ≥1 occlusion and 75 without occlusions. The accuracy of occlusion detection was greater with CTP assistance compared to CTA only (AUC 0.93 vs 0.91, p= 0.03 for proximal and AUC 0.88 vs 0.81, p<0.001 for distal). Distal occlusion detection accuracy improved with CTP in neurologists and in radiologists, whereas improved proximal occlusion detection accuracy was only present in neurologists. Adding CTP improved distal occlusion detection in experienced and less experienced raters. Proximal occlusion detection accuracy improved with CTP in experienced raters, and trended towards improvement in less experienced raters.
Conclusion: Assistance of CTP maps may improve the accuracy of intracranial occlusion detection on CTA. In this study, the benefit was most profound for distal occlusions, regardless of experience level or specialty background of the rater.
Keywords: Computed tomography angiography; Ischemic stroke; Perfusion imaging.
© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.