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Updated: Jul 30, 2026
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Published on: April 14, 2014
Characterizing Anatomical Variability And Alzheimer's Disease Related Cortical Thinning in the Medial Temporal Lobe
Long Xie1, Laura E M Wisse1, Sandhitsu R Das1,2
1Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, USA.
Abstract:
The perirhinal cortex (PRC) is a site of early neurofibrillary tangle (NFT) pathology in Alzheimer's disease (AD). Subtle morphological changes in the PRC have been reported in MRI studies of early AD, which has significance for clinical trials targeting preclinical AD. However, the PRC exhibits considerable anatomical variability with multiple discrete variants described in the neuroanatomy literature. We hypothesize that different anatomical variants are associated with different patterns of AD-related effects in the PRC. Single-template approaches conventionally used for automated image-based brain morphometry are ill-equipped to test this hypothesis. This study uses graph-based groupwise registration and diffeomorphic landmark matching with geodesic shooting to build statistical shape models of discrete PRC variants and examine variant-specific effects of AD on PRC shape and thickness. Experimental results demonstrate that the statistical models recover the folding patterns of the known PRC variants and capture the expected shape variability within the population. By applying the proposed pipeline to a large dataset with subjects from different stages in the AD spectrum, we find 1) a pattern of cortical thinning consistent with the NFT pathology progression, 2) different patterns of the initial spatial distribution of cortical thinning between anatomical variants, and 3) an effect of AD on medial temporal lobe shape. As such, the proposed pipeline could have important utility in the early detection and monitoring of AD.
Insights
Alzheimer's disease (AD) affects the perirhinal cortex (PRC) differently based on its anatomical variants. This study reveals variant-specific patterns of brain thinning, aiding early AD detection.
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.
