Abstract 54: Investigating the Relationship Between Reperfusion and Cerebral Edema Using Novel Cerebrospinal Fluid and Net Water Uptake Biomarkers

Abstract

Introduction: Studies show that successful reperfusion after large-vessel occlusion (LVO) stroke can lead to reduced mass effect and midline shift (MLS). However, MLS typically occurs late in the edema cascade and only develops in approximately half of patients treated with endovascular thrombectomy (EVT). This study aimed to explore the connection between reperfusion and cerebral edema in more detail, utilizing CSF volumetrics and tissue water concentration. Methods: Using a deep-learning algorithm, we measured cerebrospinal fluid (CSF) volumes and their interhemispheric ratio on CT images at baseline, 24 hours, and 72 hours following a stroke. Automated segmentation of infarct regions on follow-up scans was used to measure net water uptake (NWU), the ratio of density within infarcted tissue relative to the mirrored contralateral region. The change in edema markers from baseline to 24 hours, as well as 72-hour NWU, were dichotomized at the median into significant edema growth and low/moderate edema growth. Reperfusion status was assessed by the modified thrombolysis in cerebral infarction score. Results: This study included 137 patients (mean age 69 ± 15, mean NIHSS 14) with LVO stroke who underwent EVT. There was a gradual decrease in the CSF ratio change at 24 and 72 hours with lower (worse) TICI scores (p=0.023 and p<0.001, respectively, Figure 1A). After adjusting for age, admission NIHSS, and ASPECT score, successful reperfusion was associated with lower odds of significant edema by CSF ratio change at 24 hours (aOR 0.25, 95% CI 0.1-0.6, p=0.002) and NWU at 72 hours (aOR 0.26, 95% CI 0.1-0.7, p=0.01) when compared with unsuccessful reperfusion. Lower CSF ratio growth and NWU at 24 hours were significantly associated with lower global disability measured by the modified Rankin Scale at 90 days (p<0.001 and p=.008, respectively, Figure 1B). Conclusions: Successful reperfusion is associated with reduced edema and better functional outcomes following thrombectomy.