LAUSR

OBJECTIVE People with chronic HIV exhibit lower regional brain volumes compared to people without HIV (PWOH). Whether imaging alterations observed in chronic infection occur in acute HIV infection (AHI) remains unknown. DESIGN Cross-sectional study of Thai participants with AHI. METHODS 112 Thai males with AHI (age 20-46) and 18 male Thai PWOH (age 18-40) were included. Individuals with AHI were stratified into early (Fiebig I-II; n = 32) and late (Fiebig III-V; n = 80) stages of acute infection using validated assays. T1-weighted scans were acquired using a 3T MRI performed within five days of antiretroviral therapy (ART) initiation. Volumes for the amygdala, caudate nucleus, hippocampus, nucleus accumbens, pallidum, putamen, and thalamus were compared across groups. RESULTS Participants in late Fiebig stages exhibited larger volumes in the nucleus accumbens (8% larger; p = .049) and putamen (19%; p < .001) when compared to participants in the early Fiebig. Compared to PWOH, participants in late Fiebig exhibited larger volumes of the amygdala (9% larger; p = .002), caudate nucleus (11%; p = .005), nucleus accumbens (15%; p = .004), pallidum (19%; p = .001), and putamen (31%; p < .001). Brain volumes in the nucleus accumbens, pallidum, and putamen correlated modestly with stimulant use over the past four months among late Fiebig individuals (ps < .05). CONCLUSIONS Findings indicate that brain volume alterations occur in acute infection, with the most prominent differences evident in the later stages of AHI. Additional studies are needed to evaluate mechanisms for possible brain disruption following ART, including viral factors and markers of neuroinflammation.