MRI-Based Medial Temporal Atrophy May Reflect Amyloid PET Positivity in Cognitively Normal Individuals: A Preliminary...

Area of Science:

• Neuroimaging
• Alzheimer's Disease Research

Background:

• Early detection of Alzheimer's disease (AD) is crucial for timely intervention.
• Amyloid-beta (Aβ) deposition is an early pathological hallmark of AD.
• Cognitively normal individuals can harbor underlying AD pathology.

Purpose of the Study:

• To investigate if MRI-based medial temporal lobe morphometry predicts amyloid positron emission tomography (PET) positivity.
• To assess the utility of structural MRI as an early biomarker for AD pathology in cognitively normal individuals.

Main Methods:

• Retrospective analysis of 16 cognitively normal participants (8 amyloid PET-positive, 8 PET-negative).
• Amyloid PET using florbetapir with visual and Centiloid analysis.
• MRI-derived volumetric analysis of medial temporal atrophy using VSRAD.
• Receiver operating characteristic (ROC) analysis to evaluate diagnostic performance.

Main Results:

• The amyloid PET-positive group showed a trend towards greater medial temporal atrophy compared to the PET-negative group.
• Centiloid values positively correlated with medial temporal morphometric indices.
• The volume-of-interest-to-gray-matter ratio demonstrated fair diagnostic discrimination (AUC = 0.83).

Conclusions:

• Subtle hippocampal alterations on routine structural MRI may reflect early amyloid pathology in cognitively normal individuals.
• MRI-based morphometry shows potential as an adjunctive biomarker for early AD detection.
• These findings support the use of MRI in identifying individuals at risk for AD before significant cognitive decline.