• Villemagne, Victor
• Salvado, Olivier
• Xiao, Di
• Masters, Colin
• Martins, Ralph
• Chetelat, Gael
• Rueda, Andrea
• Favreau, Jean-Marie
• Szoeke, Cassandra
• Barra, Vincent
• Acosta, Oscar
• Ellis, Kathryn
• Fripp, Jurgen
• Rowe, Chris
• Gris, Florence
• Bonner, Erik
• Raniga, Parnesh
• Ames, David

Abstract

Magnetic resonance (MR) provides a non-invasive imaging technique to investigate changes in the brain resulting from normal aging or neurodegenerative disorders such as Alzheimer's disease (AD). Performing accurate analysis of brain imaging data for population studies is challenging because of the interindividual anatomical variability. In this paper we present a newly developed surface-based processing pipeline that allows accurate vertice-wise statistical comparisons of brain modifications, such as cortical thickness (CTE). The brain is first segmented into the three main brain tissue types: white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF), CTEis computed after which a topology corrected mesh is generated. Partial inflation and non rigid registration to a common space using shape context are then performed. Each of the steps was validated using MR images from the OASIS database. We also applied the pipeline to a sample of individuals from the AIBL study on AD. Results were compared with Freesurfer (FS). For a population of 50 individuals we found a strong correlation between CTE computed with FS in all the regions of the brain (average=0.62 left and=0.64 right hemispheres). We finally computed changes in CTE in 32 AD patients and 81 healthy elderly individuals (HC). Significant differences were found in regions known to be affected in AD (temporal lobe, hippocampus, cingulate). We demonstrated the validitity of the method for use in clinical studies which provides an alternative to well established technniques and allows the comparison between different imaging biomarkers for the study of neurodegenerative diseases.

Topics

• impedance spectroscopy
• surface
• aging
• aging