Characterizing Anatomical Variability And Alzheimer's Disease Related Cortical Thinning in the Medial Temporal Lobe...

Area of Science:

• Neuroscience
• Radiology
• Pathology

Background:

• The perirhinal cortex (PRC) shows early neurofibrillary tangle (NFT) pathology in Alzheimer's disease (AD).
• Existing MRI studies report subtle morphological changes in the PRC in early AD, crucial for clinical trials.
• The PRC has significant anatomical variability with multiple discrete variants, complicating morphometric analyses.

Purpose of the Study:

• To investigate if distinct anatomical variants of the PRC are associated with different patterns of AD-related effects.
• To develop and apply novel statistical shape modeling techniques capable of analyzing variant-specific AD impacts.

Main Methods:

• Utilized graph-based groupwise registration and diffeomorphic landmark matching with geodesic shooting.
• Constructed statistical shape models for discrete PRC variants.
• Analyzed a large dataset across the AD spectrum to examine variant-specific shape and thickness changes.

Main Results:

• Statistical models successfully recovered known PRC folding patterns and population variability.
• Identified cortical thinning patterns consistent with NFT progression in the PRC.
• Observed distinct initial spatial distributions of cortical thinning among different PRC anatomical variants.
• Detected significant effects of AD on medial temporal lobe shape.

Conclusions:

• The developed pipeline effectively models PRC anatomical variants and their specific responses to AD.
• Findings highlight the importance of considering PRC anatomical variability in AD research.
• The methodology shows promise for early AD detection and monitoring through precise morphometric analysis.