Accuracy and Variability of Spatial Localization of Infarct Core Predicted by CT Perfusion

In patients with acute ischemic stroke, CT perfusion (CTP)-derived infarct core is valuable for prognostication, triage and transfer decision-making, and for informing studies of emerging therapeutic targets. In this study, we compare the accuracy and variability of the infarct core predicted by 2 FDA-cleared CTP programs, using diffusion-weighted MRI (DWI) as the reference standard.

We analyzed 61 stroke patients who underwent admission CTP and DWI within 90 minutes. Infarct core was estimated using relative cerebral blood flow thresholds and compared with DWI-derived ground truth. After coregistration of CTP and DWI, Dice similarity coefficients were calculated to quantify the topographic concordance of the infarct core.

The CTP-determined infarct core volumes were significantly correlated with DWI but demonstrated substantial variability and bias. Our results showed limited topographic overlap, with median dice scores of 0.367 (CTP-A) and 0.289 (CTP-B). However, in patients with larger infarcts (volumes ≥50 mL), CTP provides more reliable estimates of spatial agreement, reaching median Dice scores of 0.61 (CTP-A) and 0.47 (CTP-B).

Although these findings show a generally low accuracy of CTP estimation, they suggest that CTP may offer clinically meaningful insights for decision-making in the large-core setting and inform the design of future trials.