title: Symmetry of the fornix using diffusion tensor imaging.
abstract: OBJECTIVE
  To: 1) Present fornix tractography in its entirety for 20 healthy individuals to assess variability. 2) Provide individual and groupwise whole tract diffusion parameter symmetry assessments prior to clinical application. 3) Compare whole tract diffusion parameter assessments with tract-based spatial statistics (TBSS).
  
  
  METHODS
  Diffusion tensor imaging (DTI) data were acquired on a 3T Siemens magnetic resonance imaging (MRI) system using a single-shot spin echo planar imaging (EPI) sequence. Individual fornix tractography was conducted and whole tract diffusion parameter symmetries assessed. Whole tract results were compared with asymmetry contrasts conducted with voxelwise statistical analysis of diffusion parameters using TBSS.
  
  
  RESULTS
  The fornix tract could be visualized in its entirety including the columns, body, crura, and fimbria. Contrary to the crus and body, there were some tractography inconsistencies of the columns and fimbria across subjects. Although whole tract diffusion parameter asymmetries were nonsignificant, fractional anisotropy (FA) values bordered on statistical significance (P = 0.052). Using TBSS, significant FA asymmetries were identified (P ≤ 0.01, corrected).
  
  
  CONCLUSIONS
  The findings demonstrate consistency of fornix tractography as well as some variability in the columns and fimbria. While parametric assessment demonstrates diffusion parameter symmetry, permutation-based TBSS analysis reveals significant FA asymmetries in the crura and fimbriae.
authors.affiliation: Alberta Innovates Technology Futures, MR Technology, Winnipeg, MB, Canada; Biopsychology Program Department of Psychology, University of Winnipeg, Winnipeg, MB, Canada; National Research Council Institute for Biodiagnostics, MR Technology, Winnipeg, MB, Canada.
authors.forename: Uta N
authors.initials: UN
authors.lastname: Sboto-Frankenstein
authors.forename: Tiffany
authors.initials: T
authors.lastname: Lazar
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Bolster
authors.forename: Sunny
authors.initials: S
authors.lastname: Thind
authors.forename: Patricia
authors.initials: P
authors.lastname: Dreessen de Gervai
authors.forename: Marco L H
authors.initials: ML
authors.lastname: Gruwel
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Smith
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Tomanek
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D020712:Fornix, Brain / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: TBSS; asymmetry; diffusion tensor imaging; fornix; tractography