Multimodal MRI Insights into Glymphatic Clearance and Blood-Brain Barrier Integrity in Healthy Aging

Motivation: Aging is associated with impaired CSF clearance in preclinical models, but its impact on blood-brain barrier (BBB) health and glymphatic function in humans remains unclear. Goal(s): We aimed to uncover multimodal MRI insights into BBB health and glymphatic clearance in healthy aging. Approach: Diffusion-prepared arterial spin labeling was used to measure water exchange rate (Kw) as a marker of BBB integrity, and diffusion tensor imaging along perivascular spaces (DTI-ALPS) was used to assess glymphatic function. Results: In older individuals, we observed reduced whole-brain Kw, increased white matter free water accumulation, and reduced DTI-ALPS. Our findings directly associated Kw with glymphatic clearance measures. Impact: This study provides novel multimodal MRI insights into how BBB integrity and glymphatic function are altered in healthy aging. These findings could pave the way for advancing MRI biomarkers aimed at preserving cognitive health in aging populations.