Multiphase computed tomography angiography (mCTA) derived source images in acute ischemic stroke: Beyond collaterals. Can it obviate the need for computed tomography perfusion (CTP)?

Abstract

Background and purposeTo compare Multiphase CT Angiography derived source images (mCTA-SI) in acute ischemic stroke (AIS) with CT Perfusion (CTP) derived automated color maps of cerebral blood flow (CBF) and cerebral blood volume (CBV) and to assess the comparability of mCTA-SI with CTP in the prediction of final radiological and clinical outcome. MethodsThis prospective single-centre observational study comprised of patients with AIS of the anterior circulation, presenting within 24 h and undergoing neuroimaging under stroke protocol with follow-up. Non-contrast computed tomography (NCCT), mCTA, and CTP were acquired with follow-up NCCT at 24 h and modified Rankin score (mRS) at 3 months. mCTA-SI and CTP color maps were scored by the ASPECTS (Alberta Stroke program early CT score) method and compared amongst each other and with the outcome. ROC (Receiver operating characteristic) curves were plotted considering mRS 0–2 and FIV≤ 28 ml as favourable clinical and radiological outcomes respectively. ResultsThe study included 55 patients. The 1st and 2nd phase of mCTA-SI correlated significantly with CBF maps (r = 0.845, p < 0.01, r = 0.842, p < 0.01 respectively). 3rd phase of mCTA-SI correlated significantly with CBV maps (r = 0.904, p < 0.01). A favourable functional and radiological outcome was best predicted by the 1st (AUC 0.8, 95%CI 0.671–0.896) and 2nd ( AUC 0.895, 95% CI 0.783–0.962) phase of mCTA-SI respectively. ConclusionsThe 1st and 2nd phases of mCTA-SI produces results congruent to CBF color maps and the 3rd phase of mCTA-SI simulate CBV color maps. In addition to predicting radiological and functional outcomes, mCTA can predict the salvageable and non-salvageable tissue in AIS and is non-inferior to CTP.