# Prognostic Implication of Ventricular Volumetry in Early Brain Computed Tomography after Cardiac Arrest

## TL;DR

This study shows that a smaller fourth brain ventricle volume on early CT scans after cardiac arrest is linked to worse neurological outcomes.

## Contribution

The study identifies fourth ventricular volume as an independent predictor of poor neurological outcomes after cardiac arrest.

## Key findings

- The fourth ventricle was significantly smaller in patients with poor outcomes.
- Fourth ventricular volume had a predictive accuracy comparable to the gray-to-white matter ratio.
- Combining measures improved sensitivity for predicting poor outcomes.

## Abstract

Brain swelling after cardiac arrest may affect brain ventricular volume. This study aimed to investigate the prognostic implications of ventricular volume on early thin-slice brain computed tomography (CT) after cardiac arrest. We measured the gray-to-white matter ratio (GWR) and the characteristics and volumes of the lateral, third, and fourth ventricles. The primary outcome was a poor 6-month neurological outcome. Of the 166 patients, 115 had a poor outcome. The fourth ventricle was significantly smaller in the poor outcome group (0.58 cm3 [95% CI, 0.43–0.80]) than in the good outcome group (0.74 cm3 [95% CI, 0.68–0.99], p < 0.001). Ventricular characteristics and other ventricular volumes did not differ between outcome groups. The area under the curve for the fourth ventricular volume was 0.68, comparable to 0.69 for GWR. Lower GWR (<1.09) and lower fourth ventricular volume (<0.41 cm3) predicted poor outcomes with 100% specificity and sensitivities of 8.7% (95% CI, 4.2–15.4) and 20.9% (95% CI, 13.9–29.4), respectively. Combining these measures improved the sensitivity to 25.2% (95% CI, 17.6–34.2). After adjusting for covariates, the fourth ventricular volume was independently associated with neurologic outcome. A marked decrease in fourth ventricular volume, with concomitant hypoattenuation on CT scans, more accurately predicted outcomes.