Abstract TP68: Predictive Value of CT Perfusion in Hyper Acute Ischemic Stroke Patients

Abstract

Introduction: Perfusion imaging has been an integral part in patient selection for Endovascular Thrombectomy (EVT) in the extended window. In studies evaluating perfusion imaging in the early window, the mean time from symptom onset to perfusion imaging was greater than 90 minutes. Objective: To determine the accuracy of perfusion imaging core volume compared to final infarct volume in patients presenting in the hyper acute period. Methods: We performed a retrospective analysis on a prospectively collected stroke data base from January 2018 to July 2019. We included patients with intracranial large vessel occlusion (anterior circulation) who presented within 90 minutes of symptom onset and underwent perfusion imaging with CT-perfusion (CT-P) with subsequent EVT. We collected demographics, clinical and imaging data as well as procedural variables. Final infarct volume on CTH or MRI brain (done> 24hr post EVT) was calculated manually using PACS volume analysis software. RAPID CT-P Software was used for core measurement and CBF<30% was used to predict core. Results: Out of 242 patients who underwent EVT, 22 (9%) patients met inclusion criteria. Of these, 32% (7/22) were males and 68 %( 15/22) were females. Median age was 79 yrs (interquartile range (IQR) 66.7 - 85.2) and median NIHSS was 16 (IQR 14 - 21). M1 occlusion was seen in 59% while, 27% had ICA terminus occlusion and 14% had proximal M2 occlusion. Median core volume pre EVT was 14.5ml (IQR 6.7 - 36.7) and final median infarct volume was 9.6ml (IQR 1.2 - 24.3). Most patients, had final infarct volume calculated on MRI 73 %( 16/22) while 27% (6/22) had follow up CTH. CT- P overestimated the final stroke volume in 55% (12/22 patients) of patients. In a subgroup of 5 patients who presented within 60 minutes of symptoms onset, 80% (4/5 patients) had an over estimated core on CT-P with a median predicted core of 29 ml (IQR 13 - 35) and median final infarct volume of 0.2ml (IQR 0.1 - 3.7). Conclusion: CT-P using CBF < 30% may overestimate the core infarct volume in patients presented in the hyper acute window (<90min). Caution is advised when utilizing CTP in the early time window.