BACKGROUND AND OBJECTIVES: To assess the accuracy of baseline CT perfusion ischemic core estimates.METHODS: From SELECT, a prospective multicenter cohort study of imaging selection, EVT patients who achieved complete reperfusion (modified Thrombolysis In Cerebral Ischemia (mTICI) score=3) and had follow-up Diffusion Weighted Imaging (DWI) available were evaluated. Follow-up DWI lesions were co-registered to baseline CT Perfusion (CTP). The difference between baseline CTP core (relative Cerebral Blood Flow (rCBF) <30%) volume and follow-up infarct volume was classified as over-estimation (core=10mL larger than infarct), adequate, or under-estimation (core =25 ml smaller than infarct) and spatial overlap was also evaluated.RESULTS: Of 101 included patients, median time from Last Known Well (LKW) to imaging acquisition was 138 (82 - 244) min. The median baseline ischemic core estimate was 9(0-31.9) mL and median follow-up infarct volume was 18.4(5.3-68.7) mL. All 6/101(6%) patients with overestimation of the subsequent infarct volume were imaged within 90 minutes of LKW and achieved rapid reperfusion (within 120 min of CTP). Using rCBF<20% threshold to estimate ischemic core in patients presenting within 90 minutes eliminated overestimation. Volumetric correlation between the ischemic core estimate and follow-up imaging improved as LKW time to imaging acquisition increased - Spearman's rho: <90 min: 0.33 (p=0.049), 90-270 min: 0.63 (p<0.0001), >270 min: 0.86 (p<0.0001). Assessment of the spatial overlap between baseline CTP ischemic core lesion and follow-up infarct demonstrated a median of 3.2(0.0-9.0) mL of estimated core fell outside the subsequent infarct. These regions were predominantly in white matter.DISCUSSION: Significant overestimation of irreversibly injured ischemic core volume was rare, only observed in patients who presented within 90 minutes of LKW and achieved reperfusion within 120 minutes of CTP acquisition, and occurred primarily in white matter. Use of a more conservative (rCBF<20%) threshold for estimating ischemic core in patients presenting within 90 minutes eliminated all significant overestimation cases.
View details for DOI 10.1212/WNL.0000000000200269
View details for PubMedID 35450966