Brain CT perfusion improves intracranial vessel occlusion detection on CT angiography

To evaluate whether brain CT perfusion (CTP) aids in the detection of intracranial vessel occlusion on CT angiography (CTA) in acute ischemic stroke. Medical-ethical committee approval of our hospital was obtained and informed consent was waived. Patients suspected of acute ischemic stroke who underwent non-contrast CT(NCCT), CTA and whole-brain CTP in our center in the year 2015 were included. Three observers with different levels of experience evaluated the imaging data of 110 patients for the presence or absence of intracranial arterial vessel occlusion with two strategies. In the first strategy, only NCCT and CTA were available. In the second strategy, CTP maps were provided in addition to NCCT and CTA. Receiver-operating-characteristic (ROC) analysis was used for the evaluation of diagnostic accuracy. Overall, a brain perfusion deficit was scored present in 87–89% of the patients with an intracranial vessel occlusion, more frequently observed in the anterior than in the posterior circulation. Performance of intracranial vessel occlusion detection on CTA was significantly improved with the availability of CTP maps as compared to the first strategy (P=0.023), due to improved detection of distal and posterior circulation vessel occlusions (P-values of 0.032 and 0.003 respectively). No added value of CTP was found for intracranial proximal vessel occlusion detection, with already high accuracy based on NCCT and CTA alone. The performance of intracranial vessel occlusion detection on CTA was improved with the availability of brain CT perfusion maps due to the improved detection of distal and posterior circulation vessel occlusions.