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IC‐P‐072: Changes in cortical thickness in asymptomatic individuals at genetic risk for Alzheimer's disease
Author(s) -
Bassett Susan S.,
Bazin PierreLouis,
Cristinzio Catherine,
Pham Dzung L.
Publication year - 2009
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2009.05.626
Subject(s) - parahippocampal gyrus , asymptomatic , temporal lobe , medicine , cognition , neuroimaging , parietal lobe , neuroscience , middle frontal gyrus , cardiology , psychology , audiology , epilepsy
Background: To date, the PET provides sensitive diagnostic markers to predict the evolution of patients from amnestic Mild Cognitive Impairment (aMCI) to clinically probable Alzheimer’s Disease (AD). Nonetheless, owing to the greater accessibility of morphologic MRI, it would be clinically helpful to find out morphologic diagnostic marker. The present study aimed at investigating sulcal morphology, as a potential diagnostic marker, in patients with aMCI. Different indices of the sulcal morphology were thus studied according to their clinical outcome (converters to AD or non-converters), and in relation to their cognitive decline. Methods: Seventeen aMCI patients underwent MRI scans at inclusion. MRI data were bias corrected and segmented into grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) using the VBM5.1 toolbox of SPM5. For each patient, these segmentations defined the GM/CSF interface as well as the GM/WM interface. The folding pattern was then extracted from each MRI in their native space using BrainVISA and labelled using a probabilistic folding template. Two indices of the sulcal morphology, independent of the brain size, were assessed for each sulcus: the fold opening and the surrounding cortical thickness. Results: The fold opening of the posterior calloso-marginal fissure, rhinal sulcus, orbito-frontal sulci and central sulcus was higher in converters than in non-converters. A higher initial fold opening of the collateral fissure, orbito-frontal sulci, rhinal sulcus, inter-parietal fissure and infra-parietal sulcus was associated with subsequent cognitive decline. The surround cortical thickness of the temporo-polar sulcus, posterior calloso-marginal fissure, orbito-frontal sulci, central sulcus, rhinal sulcus, collateral fissure, parieto-occipital sulcus was higher in converters than in non-converters. A higher initial surrounding cortical thickness of the temporo-polar and temporal sulci, collateral fissure, inter-parietal fissure was associated with subsequent cognitive decline. Conclusions: These preliminary results suggest that initial modifications of the sulcal morphology encompassing not only the hippocampal area but also the frontal, posterior cingulate and temporo-parietal as well as temporal regions are associated with their clinical outcome or subsequent cognitive decline. Interestingly, these regions correspond to previously highlighted either atrophic or hypometabolic areas. However, the predictive value of a specific sulcal alteration pattern remains to be isolated and evaluated.