Comparing the benefit of ASPECTS on maximum intensity projection images of computed tomography angiography to source images and noncontract computed tomography in predicting infarct volume and collaterals extent.

Introduction: In acute ischemic strokes (AIS), the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and CT perfusion (CTP) are commonly used to determine mechanical thrombectomy eligibility. Prior work suggests that CTA source image (CTA-SI) ASPECTS (CTA) and a newly described CTA maximum intensity projection (CTA-MIP) ASPECTS (MIP) better predict the final infarct core. Our goal was to compare MIP to CTA and non-contrast CT ASPECTS (NCCT) for predicting ischemic core and collaterals established by CTP.

Methods And Materials: A single institution, retrospective database for AIS due to internal carotid artery (ICA) or proximal middle cerebral artery (MCA) occlusions between January 2016 and February 2021 was reviewed. We rated ASPECTS on NCCT, CTA-SI, and CTA-MIP at baseline, then used the automated RAPID software to measure CTP ischemic core volume. The accuracy of each ASPECTS in predicting ischemic core volume (ICV) >70 cc and Hypoperfusion intensity ratio (HIR) >0.4 was compared using the receiver operating characteristic (ROC) curve.

Results: 122/319 patients fulfilled the inclusion criteria. Area under the curve (AUC) for MIP was significantly higher than NCCT and CTA for predicting ICV >70 cc (0.95 vs. 0.89 and 0.95 vs. 0.92, P =0.03 and P = 0.04). For predicting HIR >0.4, AUC for MIP was significantly higher than NCCT and CTA (0.85 vs. 0.72 and 0.85 vs. 0.81, P < 0.001 and P < 0.01).

Conclusion: The predictive accuracy of detecting ischemic stroke with ICV >70cc and HIR >0.4 can be significantly improved using the MIP instead of CTA or NCCT.