title: An enhanced voxel-based morphometry method to investigate structural changes: application to Alzheimer's disease.
abstract: BACKGROUND
  When characterizing regional cerebral gray matter differences in structural magnetic resonance images (sMRI) by voxel-based morphometry (VBM), one faces a known drawback of VBM, namely that histogram unequalization in the intensity images introduces false-positive results.
  
  
  METHODS
  To overcome this limitation, we propose to improve VBM by a new approach (called eVBM for enhanced VBM) that takes the histogram distribution of the sMRI into account by adding a histogram equalization step within the VBM procedure. Combining this technique with two most widely used VBM software packages (FSL and SPM), we studied GM variability in a group of 62 patients with Alzheimer's disease compared to 73 age-matched elderly controls.
  
  
  RESULTS
  The results show that eVBM can reduce the number of false-positive differences in gray matter concentration.
  
  
  CONCLUSIONS
  Because it takes advantage of the properties of VBM while improving sMRI histogram distribution at the same time, the proposed method is a powerful approach for analyzing gray matter differences in sMRI and may be of value in the investigation of sMRI gray and white matter abnormalities in a variety of brain diseases.
authors.affiliation: Laboratoire d'Imagerie Fonctionnelle, and LINeM, GHU Pitié-Salpêtrière, Inserm, UPMC Univ Paris 06, UMR_S 678, 91 bd de l'Hôpital, 75634, Paris, Cedex 13, France.
authors.forename: Xingfeng
authors.initials: X
authors.lastname: Li
authors.forename: Arnaud
authors.initials: A
authors.lastname: Messé
authors.forename: Guillaume
authors.initials: G
authors.lastname: Marrelec
authors.forename: Mélanie
authors.initials: M
authors.lastname: Pélégrini-Issac
authors.forename: Habib
authors.initials: H
authors.lastname: Benali
mesh_terms: D000368:Aged; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012984:Software