Grey-to-white matter ratio values in early head CT as a predictor of neurological outcomes in survivors of out-of-hospital cardiac arrest based on severity of hypoxic-ischemic brain injury

Background : Hypoxic-ischemic brain injury (HIBI) is a common complication of out-of-hospital cardiac arrest (OHCA). Objectives : We investigated whether grey-to-white matter ratio (GWR) values, measured using early head computed tomography (HCT), were associated with neurological outcomes based on the severity of HIBI in survivors of OHCA. Methods : This retrospective multicenter study included adult comatose OHCA survivors who underwent an HCT scan within 2 hours after the return of spontaneous circulation. HIBI severity was assessed using the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) scale (low, moderate, and severe). Poor neurological outcomes were defined as Cerebral Performance Categories 3–5 at 6 months after OHCA. Results : Among 354 patients, 27% were women and 224 (63.3%) had poor neurological outcomes. The distribution of severity was 19.5% low, 47.5% moderate, and 33.1% severe. The area under the receiver operating curves of the GWR values for predicting rCAST severity (low, moderate, and severe) were 0.52, 0.62, and 0.79, respectively. The severe group had significantly higher predictive performance than the moderate group (p=0.02). Multivariate logistic regression analysis revealed a significant association between GWR values and poor neurological outcomes in the moderate group (adjusted odds ratio=0.012, 95% CI 0.0–0.54, p=0.02). Conclusions : In this cohort study, GWR values measured using early HCT demonstrated variations in predicting neurological outcomes based on HIBI severity. Furthermore, GWR in the moderate group was associated with poor neurological outcomes.