title: Diffusion tensor imaging of the optic nerve in subacute anterior ischemic optic neuropathy at 3T.
abstract: OBJECTIVE
  DTI can provide in vivo information about the pathology of optic nerve disease, but there is no study of DTI in the setting of ION, the most frequent acute optic neuropathies in patients over 50 years of age. Our aim was to investigate the potential of DTI in the diagnosis of subacute AION at 3T.
  
  
  METHODS
  Twenty-six patients with unilateral AION and 15 healthy controls were enrolled in this study. DTI and pattern VEP were performed on the ONs of all subjects. The mean ADC, FA, and eigenvalue maps were obtained for quantitative analysis. Quantitative electrophysiology was also performed on all subjects.
  
  
  RESULTS
  The mean ADC and orthogonal eigenvalue λ(⊥) in affected nerves increased, and the mean FA was reduced compared with clinically unaffected contralateral nerves (P < .001) and control nerves (P < .001). However, no significant changes of the mean principal eigenvalue λ(‖) in affected nerves compared with unaffected contralateral nerves (P = .13) and control nerves (P = .14) were seen. There was a significant correlation of whole-field VEP amplitude with ADC (r = -0.63, P = .001) and λ(⊥) (r = -0.47, P = .015) but no correlation with FA (P = .06) and λ(‖) (P = .06).
  
  
  CONCLUSIONS
  DTI measurement of ischemic ONs provides in vivo information about pathology and may serve as a biomarker of axonal and myelin damage in AION.
authors.affiliation: Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, Henan, China.
authors.forename: M-Y
authors.initials: MY
authors.lastname: Wang
authors.forename: P-H
authors.initials: PH
authors.lastname: Qi
authors.forename: D-P
authors.initials: DP
authors.lastname: Shi
mesh_terms: D000328:Adult; D000368:Aged; D001369:Axons / Q000473:pathology*; D015897:Comorbidity; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000473:pathology*; D009900:Optic Nerve / Q000473:pathology*; D018917:Optic Neuropathy, Ischemic / Q000453:epidemiology / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014794:Visual Fields