Abstract P362: A Volumetric Comparison of Computed Tomography Perfusion Rapid Core Volume in Different Time Frames With Diffusion-Weighted Imaging Infarct Volume in the Post-Thrombectomy Patients After Large Vessel Occlusion

Abstract

Introduction: The Computed Tomography Perfusion (CTP) RAPID software is widely used for the patient selection for mechanical thrombectomy (MT) after anterior circulation large vessel occlusion (LVO). There is a notion that it overestimates the core volume (CV) in an earlier time frame from symptom onset. We compared the accuracy of CTP RAPID estimated CV in different time frames with diffusion weighted imaging (DWI) infarct volume (IV). Method: A retrospective data review of patients who underwent MT for anterior circulation LVO with TICI 2b/3 reperfusion from 2017 to 2019 was done. Patients with baseline CTP and follow up 36-hour MRI was included. Patients with parenchymal hematoma, graded as per ECASS II classification were excluded. CTP time was dichotomized as 0-3 hours (hrs) and >3 hrs from symptom onset. DWI IV was calculated by ABC/2 formula. The volumetric difference (VD), defined as DWI IV minus CTP CV, core volume overestimation (CVO), defined as CTP CV minus DWI IV and CT ASPECTS was calculated. Large CV was defined as >50 ml CV. Standard descriptive statistics and independent sample T-test were used as statistical tools. Result: Total MT cases (n) were 61. Mean age (y.o) was 66 (SD 13.9) (male 57.4%). In < 3 hrs from symptom onset (n 27), mean CTP CV was 38.8 ml (SD 39.8), DWI IV was 39.6 ml (SD 51.4), VD was 0.9 ml (SD 55.2) (p 0.945) and CVO (n 11) was 39.6 ml (SD 35.7) (p 0.008). Mean large CV (n 8) was 78.3 ml (SD 25.4) with median CT ASPECTS of 8 (IQR 6.5-9) and median mRS at discharge 2 (IQR 0.8- 3.3). In >3 hrs from symptom onset (n 34), mean CTP CV was 28.81 ml (SD 47.4), DWI IV was 75.3 ml (SD 69.5), VD was 46.5 ml (SD 61.8) (p 0.002) and CVO (n 5) was 25.2 ml (SD 41.27) (p 0.60). Mean large CV (n 5) was 116.8 ml (SD 75.3) with median CT ASPECTS of 6 (IQR 5-7) and median mRS at discharge 5 (IQR 4- 6). Conclusion: Overestimated core volume on CTP was seen in more than one third cases within 3 hours from symptom onset. Large CV estimated within this time frame had higher CT ASPECTS and good functional outcome at discharge.