title: Do Alzheimer-specific microstructural changes in mild cognitive impairment predict conversion?
abstract: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that provides information on the fiber architecture of the brain by measuring water diffusion. Prior work has shown that neuronal degeneration in Alzheimer's disease (AD) and mild cognitive impairment (MCI) alters this architecture. Since the conversion rate to AD is much higher for MCI patients than for normal healthy people, it is important to identify biomarkers with a predictive value on this conversion. In this study, we applied tract-based spatial statistics (TBSS) on datasets of 15 healthy controls, 15 AD patients, and 17 MCI patients. Of these MCI patients eight remained stable, whereas nine developed AD within the first 12-18 months of follow-up investigations. Analysis using TBSS combined with a maximum likelihood regression with random effects of the fornix, the corpus callosum, and the cingulum identified significant differences between these two types of MCI patients in fractional anisotropy (FA) and radial diffusivity (DR). Thus, DTI reveals Alzheimer-specific changes in those MCI subjects that later convert, although they were clinically identical to the other MCI-patients at the time the data were acquired. This finding could lead to early identification of AD and thereby aid early clinical intervention.
authors.affiliation: Division of Medical and Biological Informatics, German Cancer Research Center, Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: van Bruggen
authors.forename: Bram
authors.initials: B
authors.lastname: Stieltjes
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Thomann
authors.forename: Peter
authors.initials: P
authors.lastname: Parzer
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Meinzer
authors.forename: Klaus H
authors.initials: KH
authors.lastname: Fritzsche
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D060825:Cognitive Dysfunction / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D018450:Disease Progression; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D020712:Fornix, Brain / Q000473:pathology; D006179:Gyrus Cinguli / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration / Q000473:pathology; D009412:Nerve Fibers / Q000473:pathology*; D009474:Neurons / Q000473:pathology