title: Evaluation of traumatic optic neuropathy in patients with optic canal fracture using diffusion tensor magnetic resonance imaging: a preliminary report.
abstract: OBJECTIVE
  To investigate the role of diffusion tensor magnetic resonance imaging (DT-MRI) in the evaluation of traumatic optic neuropathy (TON).
  
  
  METHODS
  Six patients with TON underwent DT-MRI prior to decompression surgery. DTV 2 and Volume One 1.44 software were used to measure the fractional anisotropy (FA) and the mean apparent diffusion coefficient (ADC) of the optic nerves. White matter fiber bundle tracking was used to display optic nerves.
  
  
  RESULTS
  Visual acuity was improved in 1 of the 6 patients after surgery. The mean FA of the injured eye declined significantly with regard to that of the normal eye (0.2438 ± 0.0670 vs. 0.4524 ± 0.0531; t = 8. 711; p = 0. 000). The mean ADC on the injured side increased significantly compared with that on the normal side [(1.4172 ± 0.1208) × 10(-3) mm(2)/s vs. (1.0866 ± 0.1179) × 10(-3) mm(2)/s; t = -5.316; p = 0. 003). The continuity of the intracanalicular segment of the optic nerve was interrupted in 3 patients without improved postoperative visual acuity. In 1 patient with improved postoperative visual acuity, the fiber bundle of the optic nerve was somewhat less dense in the injured eye than in the normal eye.
  
  
  CONCLUSIONS
  DT-MRI provides valuable information for evaluating the fibers of optic nerves in TON.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Qin-Tai
authors.initials: QT
authors.lastname: Yang
authors.forename: Yun-Ping
authors.initials: YP
authors.lastname: Fan
authors.forename: Yan
authors.initials: Y
authors.lastname: Zou
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Kang
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
authors.forename: Xian
authors.initials: X
authors.lastname: Liu
authors.forename: Ge-Hua
authors.initials: GH
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D019299:Decompression, Surgical; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009900:Optic Nerve / Q000473:pathology* / Q000601:surgery; D020221:Optic Nerve Injuries / Q000473:pathology* / Q000601:surgery; D010865:Pilot Projects; D011300:Preoperative Care / Q000379:methods*; D020127:Recovery of Function; D014795:Visual Pathways / Q000473:pathology* / Q000601:surgery; D055815:Young Adult