Effects of short-term exposure to moderate amounts of alcohol on brain volume

Aim: Although numerous studies have reported that chronic alcohol consumption causes brain volume reduction and cerebrospinal fluid volume increase, few studies have examined the acute effects of alcohol on brain structure. This study aims to investigate the short-term brain volume changes following alcohol administration. Methods: Moderate doses of alcohol were administered intravenously to 18 healthy volunteers for a total of 90 min to achieve a blood alcohol concentration of 0.5 mg/mL. An alcohol clamp method combined with physiologically based pharmacokinetic modeling was used to achieve fine control over blood alcohol concentration. T1 images with 3T MRI were scanned at three time points: baseline, 0 min, and 90 min after the end of alcohol administration. Cortical, subcortical, and ventricular volumes were computed after segmentation with FreeSurfer. Repeated measures analysis of variance was used to evaluate longitudinal changes in brain volume at 96 regions. Results: Acute alcohol administration increased bilateral lateral ventricular volumes, which lasted until 90 min after the end of alcohol injection. On the other hand, the volumes of total gray matter, left precentral cortex, left caudal middle frontal cortex, and left superior frontal cortex decreased after alcohol administration, but these changes disappeared 90 min after the end of alcohol administration. Conclusion: Acute injection of moderate doses of alcohol may enlarge ventricle volumes and reduce gray matter volumes. The transient volume changes caused by acute administration of alcohol may be related to changes in CSF flow and water content of brain tissue, which warrants further study.