title: A tracking-based diffusion tensor imaging segmentation method for the detection of diffusion-related changes of the cervical spinal cord with aging.
abstract: OBJECTIVE
  To compare region of interest (ROI)-based and diffusion tensor tractography (DTT)-based methods for evaluating diffusion properties of the spinal cord as a function of age.
  
  
  METHODS
  Commonly, an ROI segmentation is used to delineate the spinal cord. In this work, new segmentation methods are developed based on DTT. In a first, DTT-based, segmentation approach, the diffusion properties are calculated on the tracts. In a second method, the diffusion properties are analyzed in the spinal cord voxels that contain a certain number of tracts. We studied the changes in diffusion properties of the human spinal cord in subjects of different ages. Diffusion tensor imaging (DTI) measurements of the cervical spinal cord were acquired on 42 healthy volunteers (age range = 19-87 years). The fractional anisotropy (FA), the mean diffusivity (MD), and eigenvalues (lambda(1), lambda(2), and lambda(3)) were compared for the ROI- and DTT-based segmentation methods.
  
  
  RESULTS
  Our automatic techniques are shown to be highly reproducible and sensitive for detecting DTI changes. FA decreased (r = -0.38; P < 0.05), whereas MD and eigenvalues increased (r = +/- 0.45; P < 0.05) with age. These trends were not statistically significant for the ROI-based segmentation (P > 0.05).
  
  
  CONCLUSIONS
  DTT is a robust and reproducible technique to segment the voxels of interest in the spinal cord.
authors.affiliation: Visionlab, Department of Physics, University of Antwerp, Antwerp, Belgium. Wim.Vanhecke@ua.ac.be
authors.forename: Wim
authors.initials: W
authors.lastname: Van Hecke
authors.forename: Alexander
authors.initials: A
authors.lastname: Leemans
authors.forename: Jan
authors.initials: J
authors.lastname: Sijbers
authors.forename: Evert
authors.initials: E
authors.lastname: Vandervliet
authors.forename: Johan
authors.initials: J
authors.lastname: Van Goethem
authors.forename: Paul M
authors.initials: PM
authors.lastname: Parizel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016477:Artifacts; D002574:Cervical Vertebrae; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013116:Spinal Cord / Q000033:anatomy & histology / Q000502:physiology*