title: Diffusion tensor imaging correlates of visual impairment in multiple sclerosis and chronic optic neuritis.
abstract: OBJECTIVE
  To compare white matter (WM) injuries associated with vision loss in multiple sclerosis (MS) and optic neuritis (ON).
  
  
  METHODS
  Twenty-three patients with clinically definite relapsing-remitting MS and chronic unilateral ON and 14 neurologically healthy volunteers were monocularly tested with Sloan 100%, 2.5%, and 1.25% contrast visual acuity charts. Primary visual pathway and whole-brain WM injury were assessed with optical coherence tomography (OCT) and diffusion tensor imaging (DTI). OCT and DTI correlates of high- and low-contrast visual impairment were identified using correlation analyses.
  
  
  RESULTS
  The MS patients displayed significantly reduced retinal nerve fiber layer (RNFL) thickness and altered optic nerve and radiation DTI measures compared with the controls. In the patients, 2.5% and 1.25% contrast letter acuity in the unaffected eye correlated significantly and independently with optic nerve and optic radiation DTI measures. Visual acuity in affected eyes did not correlate with optic nerve or optic radiation DTI measures, but did correlate with DTI measures in prefrontal and temporal brain regions that were shown to connect structurally to visual cortices.
  
  
  CONCLUSIONS
  In unaffected eyes, visual impairment was associated with WM injury in the visual pathway. In contrast, irrecoverable visual impairment after ON was associated with injury to frontal WM, which potentially impairs the capacity for remapping visual processing.
authors.affiliation: Department of Physiology, Monash University, Clayton, VIC, 3800, Australia. scott.kolbe@monash.edu
authors.forename: Scott C
authors.initials: SC
authors.lastname: Kolbe
authors.forename: Mark
authors.initials: M
authors.lastname: Marriott
authors.forename: Anneke van der
authors.initials: Av
authors.lastname: Walt
authors.forename: Joanne
authors.initials: J
authors.lastname: Fielding
authors.forename: Alexander
authors.initials: A
authors.lastname: Klistorner
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mitchell
authors.forename: Helmut
authors.initials: H
authors.lastname: Butzkueven
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Kilpatrick
authors.forename: Gary F
authors.initials: GF
authors.lastname: Egan
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000175:diagnosis; D009902:Optic Neuritis / Q000150:complications* / Q000175:diagnosis; D055351:Retinal Neurons / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods*; D015354:Vision, Low / Q000175:diagnosis* / Q000209:etiology; D014792:Visual Acuity; D014795:Visual Pathways / Q000473:pathology*