title: Validation of a semiautomated spinal cord segmentation method.
abstract: OBJECTIVE
  To validate semiautomated spinal cord segmentation in healthy subjects and patients with neurodegenerative diseases and trauma.
  
  
  METHODS
  Forty-nine healthy subjects, as well as 29 patients with amyotrophic lateral sclerosis, 19 with spinal muscular atrophy, and 14 with spinal cord injuries were studied. Cord area was measured from T2 -weighted 3D turbo spin echo images (cord levels from C2 to T9) using the semiautomated segmentation method of Losseff et al (Brain [1996] 119(Pt 3):701-708), compared with manual segmentation. Reproducibility was evaluated using the inter- and intraobserver coefficient of variation (CoV). Accuracy was assessed using the Dice similarity coefficient (DSC). Robustness to initialization was assessed by simulating modifications to the contours drawn manually prior to segmentation.
  
  
  RESULTS
  Mean interobserver CoV was 4.00% for manual segmentation (1.90% for Losseff's method) in the cervical region and 5.62% (respectively 2.19%) in the thoracic region. Mean intraobserver CoV was 2.34% for manual segmentation (1.08% for Losseff's method) in the cervical region and 2.35% (respectively 1.34%) in the thoracic region. DSC was high (0.96) in both cervical and thoracic regions. DSC remained higher than 0.8 even when modifying initial contours by 50%.
  
  
  CONCLUSIONS
  The semiautomated segmentation method showed high reproducibility and accuracy in measuring spinal cord area.
authors.affiliation: Inserm U678, UPMC Univ Paris 6 UMR-S 678, Laboratoire d'imagerie fonctionnelle, Paris, France; Univ Paris 11, IFR 49, Institut fédératif de recherche en imagerie neurofonctionnelle, DSV/I2BM Neurospin, Gif-sur-Yvette, France.
authors.forename: Mohamed-Mounir
authors.initials: MM
authors.lastname: El Mendili
authors.forename: Raphaël
authors.initials: R
authors.lastname: Chen
authors.forename: Brice
authors.initials: B
authors.lastname: Tiret
authors.forename: Mélanie
authors.initials: M
authors.lastname: Pélégrini-Issac
authors.forename: Julien
authors.initials: J
authors.lastname: Cohen-Adad
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Pradat
authors.forename: Habib
authors.initials: H
authors.lastname: Benali
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000473:pathology*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013119:Spinal Cord Injuries / Q000175:diagnosis*
keywords: MRI; atrophy measurement; cross-sectional area; segmentation; spinal cord