Spatiotemporal Characteristics of BBB Functional Changes in Healthy Aging: Imaging Evidence Based on Vascular Water Exchange Imaging (VEXI)

Motivation: The blood-brain barrier (BBB) is essential for brain homeostasis and function, but its spatiotemporal patterns in aging is largely unknown. Goal(s): To explore the spatiotemporal changes of BBB permeability in healthy aging. Approach: We used the Vascular Water Exchange Imaging (VEXI) to measure the water exchange rate (AXR) across the BBB (AXRBBB) in 103 subjects from 18yr to 76yr, quantifying BBB permeability without contrast agents. Results: AXRBBB value of whole-brain gray matter and white matter increases with age, respectively. However, different brain regions exhibiting distinct AXRBBB patterns in aging, including the critical age turning point and hemispherical asymmetry. Impact: Our neuroimaging study reveals the BBB permeability's spatiotemporal patterns in healthy human aging, which is important for understanding the aging processes and provides with potential diagnosis biomarker for many brain diseases.