The association between temporal-lobe tensor-based morphometry and plasma amyloid-β in mild cognitive impairment

Area of Science:

• Neuroimaging
• Biomarker Discovery
• Alzheimer's Disease Research

Background:

• Alzheimer's disease (AD) is marked by amyloid-beta (Aβ) buildup and brain atrophy.
• The link between plasma Aβ biomarkers and regional neurodegeneration in AD is not well understood.

Purpose of the Study:

• To investigate associations between plasma Aβ42, Aβ40, and the Aβ42/40 ratio with temporal lobe atrophy.
• To analyze these associations in cognitively healthy controls (HC) and individuals with mild cognitive impairment (MCI) using tensor-based morphometry (TBM).

Main Methods:

• Longitudinal MRI and plasma biomarker data from 29 participants (14 HC, 15 MCI) in the ADNI study were analyzed.
• Tensor-based morphometry (TBM) was used to measure temporal lobe atrophy.
• Linear mixed-effects models assessed associations between plasma Aβ and TBM, adjusting for covariates and using FDR correction.

Main Results:

• Mild cognitive impairment (MCI) participants exhibited greater temporal lobe atrophy than HC.
• Plasma Aβ levels did not show consistent differences between groups.
• Limited, inconsistent associations between plasma Aβ and temporal lobe atrophy were observed at 48 months, with specific correlations in HC and MCI groups.

Conclusions:

• TBM effectively detected increased temporal lobe atrophy in MCI patients.
• Plasma amyloid biomarkers demonstrated weak and inconsistent links with longitudinal temporal lobe atrophy.
• Plasma Aβ measures may not be sufficient to reliably track regional neurodegeneration in early AD stages.