Alzheimer's Imaging Consortium

Area of Science:

• Neuroimaging
• Neuropathology
• Vascular Neurology

Background:

• White matter hyperintensities (WMHs) in Alzheimer's disease (AD) are linked to microvascular disease and AD-specific pathologies.
• Multimodal imaging is crucial for understanding WMH contributions.

Purpose of the Study:

• To investigate the distinct vascular and AD-related contributions to WMH volume and microstructure.
• To examine associations between WMH metrics, amyloid, and tau pathologies.

Main Methods:

• Utilized multimodal MRI (T1w, FLAIR, T2*w, diffusion, ASL perfusion) and PET imaging in cognitively normal (CN), mild cognitive impairment (MCI), and AD participants.
• Quantified WMH volume and assessed microstructural integrity within WMHs, perilesional regions, and adjacent normal appearing white matter (NAWM).
• Correlated imaging metrics with amyloid and tau burden and vascular risk factors.

Main Results:

• WMH volume was significantly higher in AD participants compared to MCI and CN groups.
• Amyloid burden independently predicted WMH volume, whereas tau did not.
• WMH burden was highest in amyloid-positive individuals with high vascular risk, indicating an additive effect.

Conclusions:

• Amyloid pathology and vascular risk interact to influence WMH development in Alzheimer's disease.
• Amyloid burden independently contributes to WMH volume, and vascular risk exacerbates this effect.
• Further research on spatial WMH distribution is needed to clarify their role in AD progression.