Cerebral blood flow is the optimal CT perfusion parameter for assessing XXXX core.

@entity1 @entity93 @entity422 @entity2541 @entity450 @entity98 @entity1188 @entity10334 @entity1054 @entity385
BACKGROUND AND PURPOSE: CT perfusion ( @entity93 ) is widely and rapidly accessible for imaging acute @entity385 but has limited validation. Cerebral blood volume ( @entity2541 ) has been proposed as the best predictor of @entity1188 core. We tested @entity2541 against other common @entity93 parameters using contemporaneous diffusion MRI. METHODS: @entity1 with acute @entity385 <6 hours after onset had @entity93 and diffusion @entity422 hour apart, before any reperfusion therapies. @entity93 maps of @entity1054 ( @entity1054 ), absolute and relative @entity2541 , @entity450 ( @entity450 ), mean transit time ( @entity98 ), and @entity1054 of the deconvolved tissue residue function (Tmax) were generated. The diffusion lesion was manually outlined to its maximal visual extent. Receiver operating characteristic (ROC) analysis area under the curve (AUC) was used to quantify the correspondence of each perfusion parameter to the coregistered diffusion-weighted imaging lesion. Optimal thresholds were determined (Youden index). RESULTS: In analysis of 98 @entity93 slabs (54 @entity1 , median onset to CT 190 minutes, median CT to MR 30 minutes), relative @entity450 performed best (AUC, 0.79; 95% CI, 0.77-81), significantly better than absolute @entity2541 (AUC, 0.74; 95% CI, 0.73-0.76). The optimal threshold was <31% of mean contralateral @entity450 . Specificity was reduced by low @entity450 / @entity2541 in noninfarcted white matter in cases with reduced contrast bolus intensity and @entity10334 . CONCLUSIONS: In contrast to previous reports, @entity450 corresponded with the acute diffusion-weighted imaging lesion better than @entity2541 , although no single threshold avoids detection of false-positive regions in unaffected white matter. This relates to low signal-to-noise ratio in @entity93 maps and emphasizes the need for optimized acquisition and postprocessing.
