title: Progressive Injury in Chronic Multiple Sclerosis Lesions Is Gender-Specific: A DTI Study.
abstract: OBJECTIVE
  To evaluate the longitudinal integrity of white matter tracts in patients with relapsing remitting multiple sclerosis (RRMS) as determined by changes in diffusivity indices of lesional and non-lesional white matter in the optic radiation over 12 months.
  
  
  METHODS
  The optic radiation (OR) was identified in sixty RRMS patients using probabilistic tractography. MS lesions were segmented on FLAIR T2 images and a lesion mask was intersected with the co-registered OR. Lesions within the OR were identified in 39 patients. Voxel-based analysis of axial diffusivity (AD) and radial diffusivity (RD) within OR lesions and non-lesional normal appearing white matter (NAWM) was performed at baseline and 12 months in 34 patients (five patients excluded due to new OR lesions).
  
  
  RESULTS
  Both RD and AD demonstrated much higher values within the lesions compared with non-lesional NAWM. There was a significant (p<0.001) increase of lesional AD and RD during the follow-up period. This increase, however, was driven almost entirely by the male cohort, in which a significantly greater change in both AD (M-2.7%, F-0.9%) and RD (M-4.6%, F-0.7%) was observed during the follow-up period. Non-lesional NAWM also demonstrated an increase in both AD and RD, albeit on a much lesser scale (1.0% and 0.6% respectively). In contradistinction to lesions, the diffusivity change in non-lesional NAWM was similar between sexes.
  
  
  CONCLUSIONS
  The evolution of AD and RD in chronic MS lesions over 12 months suggests ongoing inflammatory demyelinating activity accompanied by axonal loss. In addition, our findings are consistent with the recently observed trend of more rapid clinical progression in males and establish a potential in vivo biomarker of gender dichotomy by demonstrating a significantly faster rate of microstructural change in the chronic lesions of male patients with MS.
authors.affiliation: Department of Ophthalmology, Save Sight Institute, University of Sydney, Sydney, Australia.|Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia.|Sydney Neuroimaging Analysis Centre, Sydney, NSW, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Klistorner
authors.affiliation: Sydney Neuroimaging Analysis Centre, Sydney, NSW, Australia.|Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Chenyu
authors.initials: C
authors.lastname: Wang
authors.affiliation: North Shore Hospital, Sydney, NSW, Australia.
authors.forename: Con
authors.initials: C
authors.lastname: Yiannikas
authors.affiliation: Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Graham
authors.affiliation: North Shore Hospital, Sydney, NSW, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Parratt
authors.affiliation: Sydney Neuroimaging Analysis Centre, Sydney, NSW, Australia.|Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Barnett
mesh_terms: D000328:Adult; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009103:Multiple Sclerosis; D012727:Sex Characteristics; D066127:White Matter / Q000473:pathology* / Q000503:physiopathology*