Abstract WP82: Ghost Infarct Core: Ischemic Oreoverestimation by Admission CT Perfusion on Large Vessel Occlusion Stroke Patients

Abstract

Introduction: Computed Tomography Perfusion (CTP) is frequently used in patient selection for thrombectomy. However, CTP may under or overestimate the ischemic core. Recently, the concept of ghost infarct core (GIC) admission core lesion on CTP overestimates the final infarct volume) has been described. We aim to evaluate the prevalence and impact of GIC in large vessel occlusion stroke patients that underwent mechanical thrombectomy (MT) in a large institutional database. Methods: Retrospective analysis of a prospective database for consecutive thrombectomy cases between September 2010 and February 2018. Patients with CTP and calculated final infarct volumes (FIV) were included. Individuals with posterior circulation occlusion, anterior cerebral artery, or isolated extracranial internal carotid artery were excluded. We established a threshold of 10mL to identify patients with a significant GIC. Collateral grade was rated as follows: 0 = Absent collaterals in >50% of an M2 branch territory; 1 = Diminished collaterals in > 50% of an M2 branch; 2 = Diminished collaterals in < 50% of an M2 branch; 3 = collaterals equal to the contralateral hemisphere; 4 = Increased collaterals. Results: Of 1461 patients treated within the study period, 632 were included. GIC was identified in 51 (8.1%) subjects. Patients with and without GIC had comparable demographics, NIHSS, occlusion site, and ASPECTS. Multivariable logistic regression demonstrated that better reperfusion status (mTICI 0-2a vs. 2b vs. 2c-3; OR 2.0, 95% CI [1.04-3.86], p=0.038) and worse collateral scores (OR 0.46 [0.30-0.68], p<0.001) were independent predictors of GIC>10 mL. Multivariable predictors of good outcome (modified Rankin Scale0-2 at 90-days) included GIC>10mL (OR 6.5 [95% CI 1.8-23.4], p=0.004), young age, lower NIHSS, higher NCCT ASPECTS, middle cerebral artery M2 occlusion, and better reperfusion. Conclusion: GIC is an overlooked phenomenon and may inappropriately exclude patients from thrombectomy. Although patients with GIC have worse collateral status, the presence of GIC predicts good outcome in the setting of reperfusion therapy.