Measuring White Matter Changes in Alzheimer’s Disease Using a Novel Technique

Abstract

White Matter Hyperintensities (WMHs), defined as areas of increased signal intensity within white matter in T2-weighted MRIs, were once classified as “incidental findings” associated with aging. Recently, WMHs have been increasingly shown to be relevant in various diseases including Alzheimer’s disease (AD). Although MRI is commonly used to detect and measure WMHs, MRIs cannot provide us with a biological understanding of WMH. On the other hand, PET tracers can provide us with physiological information by binding to a specific molecule. In this thesis, we ask the question, are amyloid PET tracers measuring white matter changes associated with the core biomarkers of AD? Does this myelin-specific measure give us more information about white matter changes in AD? Briefly, we find that amyloid PET tracer Florbetapir (FBP) uptake in white matter is associated with various multimodal biomarkers of AD including amyloid, tau, and neurodegeneration. WMHs were only found to be associated with measures of amyloid and neurodegeneration. In sum, we provide evidence in support of the use of amyloid PET tracers for tracking white matter changes in the AD brain and evidence for their relevance in AD pathology.