title: Regional cervical cord atrophy and disability in multiple sclerosis: a voxel-based analysis.
abstract: OBJECTIVE
  To (a) apply an active surface method to map the regional distribution of cord atrophy across levels and sectors in a relatively large group of patients with multiple sclerosis (MS), (b) compare the anatomic location of cord atrophy between patients with relapsing-remitting (RR) MS and those with secondary progressive (SP) MS, and (c) assess correlations between atrophy and disability.
  
  
  METHODS
  This study was approved by the local ethical committee, and written informed consent was obtained from each participant. High-spatial-resolution magnetic resonance (MR) images of the cervical cord were acquired from 45 patients with RR MS, 26 patients with SP MS, and 67 age-matched healthy control subjects. The active surface method segmented the cord surface from C1 to C7 and created output images reformatted in planes perpendicular to the estimated cord center line. These unfolded cervical cord images were coregistered into a common standard space, and smoothed cord binary masks were used as input images for spatial statistics. Voxel-wise between-group comparisons and the correlation between regional cord atrophy versus clinical and conventional MR imaging variables were assessed with software.
  
  
  RESULTS
  Compared with control subjects, patients with RR MS showed localized clusters of atrophy in the posterior cord. Conversely, patients with SP MS showed a widespread pattern of cord atrophy, predominantly in the posterior and lateral cord columns. In patients with MS, cervical cord atrophy was correlated with clinical disability, disease duration, and, to a lesser extent, conventional MR imaging measures of brain injury. No correlation was found between cord atrophy and the presence of focal cord lesions.
  
  
  CONCLUSIONS
  Voxel-wise assessment of the regional distribution of damage in the cervical cord is feasible and might improve our understanding of the mechanisms related to the development of irreversible clinical disability in MS.
authors.affiliation: Neuroimaging Research Unit, Institute of Experimental Neurology, and Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Via Olgettina 60, Milan 20132, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Valsasina
authors.forename: Maria A
authors.initials: MA
authors.lastname: Rocca
authors.forename: Mark A
authors.initials: MA
authors.lastname: Horsfield
authors.forename: Martina
authors.initials: M
authors.lastname: Absinta
authors.forename: Roberta
authors.initials: R
authors.lastname: Messina
authors.forename: Domenico
authors.initials: D
authors.lastname: Caputo
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Comi
authors.forename: Massimo
authors.initials: M
authors.lastname: Filippi
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000473:pathology*; D009134:Muscular Atrophy, Spinal / Q000209:etiology* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity