Multi-Shell Diffusion MRI Reveals Effects of Extracranial Carotid Artery Disease on Brain Microstructure

Motivation: Extracranial carotid artery disease (ECAD) increases the risk of both stroke and dementia, indicating broader cerebrovascular and neurodegenerative effects. Goal(s): This study investigates how ECAD impacts brain microstructure, aiming to identify early markers of neurodegeneration using diffusion MRI (DMRI) metrics. Approach: Seventy-two adults with ECAD or cardiovascular risk were studied. DMRI and fixel-based analysis (FBA) were employed to assess changes in brain microstructure ipsilateral/contralateral to carotid stenosis. Results: Significant reductions in FA were found in white matter ipsilateral to stenosis, with potential compensatory increases contralaterally. DMRI metrics thus show promise as noninvasive markers of ECAD-related neurodegeneration. Impact: This study's findings provide a foundation for using diffusion MRI to identify early brain changes in patients with carotid artery disease, potentially enabling proactive interventions. Future research may explore targeted therapies to mitigate neurodegeneration linked to vascular disease.