title: Changes in white matter integrity before conversion from mild cognitive impairment to Alzheimer's disease.
abstract: BACKGROUND
  Mild cognitive impairment (MCI) may represent an early stage of dementia conferring a particularly high annual risk of 15-20% of conversion to Alzheimer's disease (AD). Recent findings suggest that not only gray matter (GM) loss but also a decline in white matter (WM) integrity may be associated with imminent conversion from MCI to AD.
  
  
  OBJECTIVE
  In this study we used Voxel-based morphometry (VBM) to examine if gray matter loss and/or an increase of the apparent diffusion coefficient (ADC) reflecting mean diffusivity (MD) are an early marker of conversion from MCI to AD in a high risk population.
  
  
  METHODS
  Retrospective neuropsychological and clinical data were collected for fifty-five subjects (MCI converters n = 13, MCI non-converters n = 14, healthy controls n = 28) at baseline and one follow-up visit. All participants underwent diffusion weighted imaging (DWI) and T1-weighted structural magnetic resonance imaging scans at baseline to analyse changes in GM density and WM integrity using VBM.
  
  
  RESULTS
  At baseline MCI converters showed impaired performance in verbal memory and naming compared to MCI non-converters. Further, MCI converters showed decreased WM integrity in the frontal, parietal, occipital, as well as the temporal lobe prior to conversion to AD. Multiple regression analysis showed a positive correlation of gray matter atrophy with specific neuropsychological test results.
  
  
  CONCLUSIONS
  Our results suggest that additionally to morphological changes of GM a reduced integrity of WM indicates an imminent progression from MCI stage to AD. Therefore, we suggest that DWI is useful in the early diagnosis of AD.
authors.affiliation: Department of General Psychiatry, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Michaela
authors.initials: M
authors.lastname: Defrancesco
authors.affiliation: Department of Neuroradiology, University Clinic Freiburg, Freiburg, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Egger
authors.affiliation: Department of Psychiatry, LKH Hall, Hall, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Marksteiner
authors.affiliation: Department of Radiology I, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Regina
authors.initials: R
authors.lastname: Esterhammer
authors.affiliation: Department of General Psychiatry, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Hartmann
authors.initials: H
authors.lastname: Hinterhuber
authors.affiliation: Department of General Psychiatry, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Eberhard A
authors.initials: EA
authors.lastname: Deisenhammer
authors.affiliation: Department of Radiology I, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Schocke
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D001284:Atrophy / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D012189:Retrospective Studies; D066127:White Matter / Q000473:pathology*