Linking white matter hyperintensities to regional cortical thinning, amyloid deposition, and synaptic density loss in Alzheimer's disease

INTRODUCTION We investigated the association between white matter hyperintensities (WMH) and regional cortical thickness, amyloid and tau deposition, and synaptic density in the WMH‐connected cortex using multimodal images. METHODS We included 107 participants (59 with Alzheimer's disease [AD]; 27 with mild cognitive impairment; 21 cognitively normal controls) with amyloid beta (Aβ) positivity on amyloid positron emission tomography (PET). The cortex connected to WMH was identified using probabilistic tractography. RESULTS We found that WMH connected to the cortex with more severe regional degeneration as measured by cortical thickness, Aβ and tau deposition, and synaptic vesicle glycoprotein 2 A (SV2A) density using 18F‐SynVesT‐1 PET. In addition, higher ratios of Aβ in the deep WMH‐connected versus WMH‐unconnected cortex were significantly related to lower cognitive scores. Last, the cortical thickness of WMH‐connected cortex reduced more than WMH‐unconnected cortex over 12 months. DISCUSSION Our results suggest that WMH may be associated with AD‐intrinsic processes of degeneration, in addition to vascular mechanisms. Highlights We studied white matter hyperintensities (WMHs) and WMH‐connected cortical changes. WMHs are associated with more severe regional cortical degeneration. Findings suggest WMHs may be associated with Alzheimer's disease–intrinsic processes of degeneration.