title: Multimodal Image Analysis in Alzheimer's Disease via Statistical Modelling of Non-local Intensity Correlations.
abstract: The joint analysis of brain atrophy measured with magnetic resonance imaging (MRI) and hypometabolism measured with positron emission tomography with fluorodeoxyglucose (FDG-PET) is of primary importance in developing models of pathological changes in Alzheimer's disease (AD). Most of the current multimodal analyses in AD assume a local (spatially overlapping) relationship between MR and FDG-PET intensities. However, it is well known that atrophy and hypometabolism are prominent in different anatomical areas. The aim of this work is to describe the relationship between atrophy and hypometabolism by means of a data-driven statistical model of non-overlapping intensity correlations. For this purpose, FDG-PET and MRI signals are jointly analyzed through a computationally tractable formulation of partial least squares regression (PLSR). The PLSR model is estimated and validated on a large clinical cohort of 1049 individuals from the ADNI dataset. Results show that the proposed non-local analysis outperforms classical local approaches in terms of predictive accuracy while providing a plausible description of disease dynamics: early AD is characterised by non-overlapping temporal atrophy and temporo-parietal hypometabolism, while the later disease stages show overlapping brain atrophy and hypometabolism spread in temporal, parietal and cortical areas.
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Lorenzi
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: Ivor J
authors.initials: IJ
authors.lastname: Simpson
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: Alex F
authors.initials: AF
authors.lastname: Mendelson
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.|MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: Sjoerd B
authors.initials: SB
authors.lastname: Vos
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: M Jorge
authors.initials: MJ
authors.lastname: Cardoso
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: Marc
authors.initials: M
authors.lastname: Modat
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, UK.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Schott
authors.affiliation: Translational Imaging Group, CMIC, UCL, London, UK.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Ourselin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000473:pathology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D064847:Multimodal Imaging / Q000379:methods*