Using Standard First-Pass Perfusion Computed Tomographic Data to Evaluate Collateral Flow in Acute Ischemic Stroke

Background and Purpose-The study aims to determine whether volume transfer constant (K^trans) maps calculated from first-pass perfusion computed tomographic data are a biomarker of cerebral collateral circulation and predict the clinical outcome in acute ischemic stroke caused by proximal arterial occlusion. Methods-Consecutive patients with acute occlusion of the middle cerebral artery who received endovascular treatment were enrolled. Digital subtraction angiography, computed tomographic angiography with maximum intensity projection, and K^trans maps were used to assess their collateral circulation. Agreement between different methods was evaluated using the χ² tests. The correlations of various radiological and clinical outcomes with the collateral flow score, as determined from K^trans maps, were calculated. Results-Seventy-five patients were included, comprising 39 women and 36 men, with a mean age of 65.3±14.6 years. Collateral flow score on K^trans maps had the highest correlation with digital subtraction angiography (κ=0.8101; P=0.9796). Twenty-five patients had poor collateral circulation on K^trans maps, 25 had intermediate collateral flow, 20 had good collateral flow, and 5 had excellent collateral flow. Better collateral circulation was associated with better clinical outcome (P<0.0001). Conclusions-K^trans maps extracted from standard first-pass perfusion computed tomography are correlated with collateral circulation status after acute proximal arterial occlusion and predictive of outcome.