title: Regional patterns of grey matter atrophy and magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups: a voxel-based analysis study.
abstract: BACKGROUND
  In multiple sclerosis (MS), demyelination and neuro-axonal loss occur in the brain grey matter (GM). We used magnetic resonance imaging (MRI) measures of GM magnetisation transfer ratio (MTR) and volume to assess the regional localisation of reduced MTR (reflecting demyelination) and atrophy (reflecting neuro-axonal loss) in relapsing-remitting MS (RRMS), secondary progressive MS (SPMS) and primary progressive MS (PPMS).
  
  
  METHODS
  A total of 98 people with MS (51 RRMS, 28 SPMS, 19 PPMS) and 29 controls had T1-weighted volumetric and magnetisation transfer scans. SPM8 was used to undertake voxel-based analysis (VBA) of GM tissue volumes and MTR. MS subgroups were compared with controls, adjusting for age and gender. A voxel-by-voxel basis correlation analysis between MTR and volume within each subject group was performed, using biological parametric mapping.
  
  
  RESULTS
  MTR reduction was more extensive than atrophy. RRMS and SPMS patients showed proportionately more atrophy in the deep GM. SPMS and PPMS patients showed proportionately greater cortical MTR reduction. RRMS patients demonstrated the most correlation of MTR reduction and atrophy in deep GM. In SPMS and PPMS patients, there was less extensive correlation.
  
  
  CONCLUSIONS
  These results suggest that in the deep GM of RRMS patients, demyelination and neuro-axonal loss may be linked, while in SPMS and PPMS patients, neuro-axonal loss and demyelination may occur mostly independently.
authors.affiliation: NMR Research Unit, University College London, UK shahrukh.mallik.09@ucl.ac.uk.
authors.forename: Shahrukh
authors.initials: S
authors.lastname: Mallik
authors.affiliation: NMR Research Unit, University College London, UK/School of Psychology: Cardiff University, UK.
authors.forename: Nils
authors.initials: N
authors.lastname: Muhlert
authors.affiliation: NMR Research Unit, University College London, UK.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Samson
authors.affiliation: NMR Research Unit, University College London, UK.
authors.forename: Varun
authors.initials: V
authors.lastname: Sethi
authors.affiliation: NMR Research Unit, University College London, UK.
authors.forename: Claudia A M
authors.initials: CA
authors.lastname: Wheeler-Kingshott
authors.affiliation: NMR Research Unit, University College London, UK.
authors.forename: David H
authors.initials: DH
authors.lastname: Miller
authors.affiliation: NMR Research Unit, University College London, UK/National Institute for Health Research, University College London Hospitals, UK.
authors.forename: Declan T
authors.initials: DT
authors.lastname: Chard
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D003711:Demyelinating Diseases / Q000473:pathology; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009103:Multiple Sclerosis / Q000473:pathology*
keywords: Multiple sclerosis; atrophy; demyelination; grey matter; magnetisation transfer ratio; voxel based analysis