Subcortical shape and volume abnormalities in an elderly HIV+ cohort

Area of Science:

• Neuroimaging
• Neuroscience
• Infectious Diseases

Background:

• Over 50% of individuals with HIV experience cognitive impairments, including issues with psychomotor functioning, processing speed, memory, and attention.
• Despite combination antiretroviral therapy, HIV+ individuals may still exhibit subcortical atrophy, indicating persistent neurological effects.
• The precise profile of HIV-associated brain changes, particularly in subcortical structures, remains incompletely understood.

Purpose of the Study:

• To investigate subcortical morphometry differences between elderly HIV+ individuals and uninfected controls using advanced neuroimaging techniques.
• To explore associations between subcortical structure shape and volume with clinical factors such as nadir CD4+ T-cell counts, viral load, and illness duration in HIV+ participants.

Main Methods:

• Parametric surface-based shape analysis of MRI scans from 63 elderly HIV+ subjects and 31 controls.
• Utilized FreeSurfer for segmentation of key subcortical structures including the thalamus, caudate, putamen, and hippocampus.
• Analyzed Jacobian determinant (JD) for tissue atrophy/expansion and radial distances (RD) for shape variations.

Main Results:

• Significant differences in the volumes of several subcortical regions were observed between HIV+ subjects and controls.
• No significant associations were found between regional brain volumes and nadir CD4+ counts, viral load, or illness duration.
• Subcortical structure shapes were significantly associated with HIV status, detectable viral RNA, and illness duration, indicating complex neurological alterations.

Conclusions:

• Elderly individuals with HIV exhibit distinct subcortical brain differences in both volumetric and shape domains compared to their uninfected counterparts.
• These findings highlight the persistent impact of HIV on brain structure, even in treated individuals, affecting cognitive health.
• Subcortical shape alterations may serve as sensitive biomarkers for HIV-associated neurological changes and disease progression.