Beyond the Blood-Brain Barrier: Water's Journey Through the Aging Brain: Exploring Cerebral Perfusion and Blood-Brain Barrier Water Exchange in Aging and Alzheimer's Disease

This thesis focuses on the investigation and application of a newly developed magnetic resonance imaging (MRI) sequence, designed to non-invasively quantify blood-brain barrier (BBB) water exchange using arterial spin labeling (ASL). Several studies were conducted with the goal of applying a standardized multi-echo BBB-ASL sequence to various ongoing research and clinical projects. Across both methodological and clinical studies, this work accomplished the following goals: 1) Set up a study design for a consortium focused on answering multiple research questions and addressing gaps in the field of non-invasive imaging of BBB water exchange time (Tex); 2) Study the reproducibility and normal values of cerebral blood flow (CBF) and Tex over age and sex; and 3) Advance the understanding of how Tex values correlate with biomarkers of early neurodegeneration and cerebrovascular pathology.