title: DTI voxelwise analysis did not differentiate older depressed patients from older subjects without depression.
abstract: BACKGROUND
  Neuroimaging has been widely used in studies to investigate depression in the elderly because it is a noninvasive technique, and it allows the detection of structural and functional brain alterations. Fractional anisotropy (FA) and mean diffusivity (MD) are neuroimaging indexes of the microstructural integrity of white matter, which are measured using diffusion tensor imaging (DTI). The aim of this study was to investigate differences in FA or MD in the entire brain without a previously determined region of interest (ROI) between depressed and non-depressed elderly patients.
  
  
  METHODS
  Brain magnetic resonance imaging scans were obtained from 47 depressed elderly patients, diagnosed according to DSM-IV criteria, and 36 healthy elderly patients as controls. Voxelwise statistical analysis of FA data was performed using tract-based spatial statistics (TBSS).
  
  
  RESULTS
  After controlling for age, no significant differences among FA and MD parameters were observed in the depressed elderly patients. No significant correlations were found between cognitive performance and FA or MD parameters.
  
  
  CONCLUSIONS
  There were no significant differences among FA or MD values between mildly or moderately depressed and non-depressed elderly patients when the brain was analyzed without a previously determined ROI.
authors.affiliation: Old Age Research Group - PROTER, Institute and Department of Psychiatry, University of São Paulo, São Paulo, Brazil. di_piparoti@yahoo.com.br
authors.forename: Diana Moitinho
authors.initials: DM
authors.lastname: Bezerra
authors.forename: Fabrício R S
authors.initials: FR
authors.lastname: Pereira
authors.forename: Fernando
authors.initials: F
authors.lastname: Cendes
authors.forename: Marcel Parolin
authors.initials: MP
authors.lastname: Jackowski
authors.forename: Eduardo Y
authors.initials: EY
authors.lastname: Nakano
authors.forename: Marco A A
authors.initials: MA
authors.lastname: Moscoso
authors.forename: Salma R I
authors.initials: SR
authors.lastname: Ribeiz
authors.forename: Renata
authors.initials: R
authors.lastname: Avila
authors.forename: Cláudio Campi de
authors.initials: CC
authors.lastname: Castro
authors.forename: Cássio M C
authors.initials: CM
authors.lastname: Bottino
mesh_terms: D000368:Aged; D000375:Aging; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000473:pathology* / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index