title: Investigation of outer cortical magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups.
abstract: BACKGROUND
  Pathological abnormalities including demyelination and neuronal loss are reported in the outer cortex in multiple sclerosis (MS).
  
  
  OBJECTIVE
  We investigated for in vivo evidence of outer cortical abnormalities by measuring the magnetisation transfer ratio (MTR) in MS patients of different subgroups.
  
  
  METHODS
  Forty-four relapsing-remitting (RR) (mean age 41.9 years, median Expanded Disability Status Scale (EDSS) 2.0), 25 secondary progressive (SP) (54.1 years, EDSS 6.5) and 19 primary progressive (PP) (53.1 years, EDSS 6.0) MS patients and 35 healthy control subjects (mean age 39.2 years) were studied. Three-dimensional (3D) 1×1×1mm(3) T1-weighted images and MTR data were acquired. The cortex was segmented, then subdivided into outer and inner bands, and MTR values were calculated for each band.
  
  
  RESULTS
  In a pairwise analysis, mean outer cortical MTR was lower than mean inner cortical MTR in all MS groups and controls (p<0.001). Compared with controls, outer cortical MTR was decreased in SPMS (p<0.001) and RRMS (p<0.01), but not PPMS. Outer cortical MTR was lower in SPMS than PPMS (p<0.01) and RRMS (p<0.01).
  
  
  CONCLUSIONS
  Lower outer than inner cortical MTR in healthy controls may reflect differences in myelin content. The lowest outer cortical MTR was seen in SPMS and is consistent with more extensive outer cortical (including subpial) pathology, such as demyelination and neuronal loss, as observed in post-mortem studies of SPMS patients.
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK r.samson@ucl.ac.uk.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Samson
authors.affiliation: Centre for Medical Image Computing, Department of Computer Sciences, University College London, UK Dementia Research Centre, Department of Neurodegenerative Diseases, Institute of Neurology, University College London, UK.
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Cardoso
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Nils
authors.initials: N
authors.lastname: Muhlert
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Varun
authors.initials: V
authors.lastname: Sethi
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Claudia Am
authors.initials: CA
authors.lastname: Wheeler-Kingshott
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Ron
authors.affiliation: Centre for Medical Image Computing, Department of Computer Sciences, University College London, UK Dementia Research Centre, Department of Neurodegenerative Diseases, Institute of Neurology, University College London, UK.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ourselin
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: David H
authors.initials: DH
authors.lastname: Miller
authors.affiliation: NMR Research Unit, UCL Institute of Neurology, London, UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, UK.
authors.forename: Declan T
authors.initials: DT
authors.lastname: Chard
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D066128:Gray Matter / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D009186:Myelin Sheath / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Multiple sclerosis; cortical grey matter; magnetization transfer ratio