Defining Large Core Infarction: Comparing the Accuracy of Non-Contrast CT ASPECTS Versus CT Perfusion Core Volume.

BACKGROUND AND PURPOSE: We evaluated agreement and performance of non-contrast head-computerized tomography (NCHCT) and CT-perfusion (CTP) in identifying large core infarct in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) undergoing endovascular therapy (EVT), using MRI as reference.

METHODS

From our prospective multicenter registry, we identified patients with LVO-AIS due to internal carotid artery or middle cerebral artery M1occlusions who underwent EVT between 2017 and 2024. Final infarct volume (FIV) was defined using 24-48 h post-EVT diffusion-weighted imaging magnetic resonance imaging (MRI-FIV). To limit infarct growth bias, only patients with CTP-to-EVT start time <3 h were included. Large core infarct was defined at FIV thresholds: 50, 70, and 100 mL. The primary outcome was agreement between NCHCT and CTP in identifying large core infarct using kappa-statistics. Large core was considered if NCHCT-ASPECTS<6 or rCBF<30% volume>70 mL on CTP (RAPID/Viz.AI). Secondary outcomes included classification accuracy of each modality relative to MRI-FIV using the area under the receiver operating characteristic curve (AUC-ROC). Sensitivity analyses were performed in subgroups with TICI 2c-3 and cases processed by RAPID.

RESULTS

Among 241 EVT-treated LVO-AIS patients, median NIHSS was 15 [IQR: 10-20], MRI-FIV 13.8 Ml [IQR: 5-41.0], ASPECTS 8 [IQR: 7-10], and CTP-predicted core 8 mL [IQR: 0-31.0]. CTP and NCHCT showed slight agreement in identifying large core (κ = 0.192) and weak-to-acceptable discrimination for identifying large core infarcts (AUC-ROC: 0.61-0.72 across MRI-FIV thresholds). Both modalities showed limited predictive ability for 90-day functional independence (AUC-ROC: 0.63-0.65). Similar findings were observed in sensitivity analyses.

CONCLUSIONS

Among LVO-AIS EVT-treated patients, NCHCT and CTP demonstrated slight agreement in classifying small versus large core, and neither technique was effective at predicting FIV or clinical outcomes.