Free Water Elevation in Alzheimer's Disease: Influence of Amyloid-Beta Deposition Beyond Brain Cell Loss
Year: 2024
Type: dissertation
Study design: Observational Study
Abstract: Free water (FW) is a neuroimaging marker calculated from diffusion tensor imaging (DTI) that has been observed to increase with disease progression in Alzheimer's disease (AD).However, it is unclear whether the increase in FW after amyloid (Aβ) deposition is solely due to brain cell loss or if other Aβ-induced mechanisms can also increase it without brain cell loss.To investigate this question, we compared regional FW, volume, and Aβ deposition in the posterior cingulate cortex (PCC) and the medial and inferior temporal cortex (MITC), which exhibit distinct AD pathologies.We enrolled 483 older adults: 182 Aβ-negative individuals with normal cognition (NC), 46 Aβ-positive preclinical AD (PREAD), 106 Aβ-positive prodromal AD (PROAD), and 149 Aβ-positive dementia due to AD (DEMAD).Regional volume, FW, and the standardized uptake value ratio of 18F-florbetaben (SUVR) were compared among participants with NC, PREAD, PROAD, and DEMAD using analysis of covariance (ANCOVA) with Bonferroni post hoc.We analyzed the effects of SUVR and volume on FW using multiple linear regression analyses.In this analysis, FW was the dependent variable, while volume and SUVR were the independent variables.Age, sex, and cerebral white matter hyperintensity (WMH) were included as covariates.As a result, continuous increases were observed in the regional SUVR and regional volume loss in all ROIs.Also, there was a consistent rise in the MITC FW.However, in PCC volume, only DEMAD demonstrated a significant decrease.In the context of multiple linear regression, the study found that both SUVR and volume were significant predictors of FW in the MITC.However, in PCC, only SUVR was able to predict FW without considering volume.This study demonstrated that after Aβ deposition in AD, an increase in FW can occur not only due to brain cell loss but also through other Aβ-induced mechanisms, even in iii cases where brain cell loss has not yet occurred.
Author: 박지은
Institution: Seoul National University
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7047468062