title: Quantitative Assessment of Optic Nerve With Diffusion Tensor Imaging in Patients With Thyroid Orbitopathy.
abstract: OBJECTIVE
  To detect abnormalities of the optic nerve in patients with thyroid orbitopathy using diffusion tensor MRI.
  
  
  METHODS
  Twenty-eight patients with Graves orbitopathy prospectively underwent diffusion tensor imaging scanning. A full ophthalmic examination including visual acuity, intraocular pressure, fundoscopy, and visual field analysis was performed. Clinical activity scores were also calculated. Fractional anisotropy (FA) and mean diffusivity values of the patients were compared with age and sex-matched healthy control subjects.
  
  
  RESULTS
  The mean FA values were decreased and mean diffusivity values were increased significantly in patients with Graves orbitopathy compared with the control subjects (p < 0.001). There was a strong reverse correlation between the FA levels and the visual fields in 4 quadrants of the optic nerve. In addition, there was a strong correlation between the degree of proptosis and the FA values in both eyes. The mean diffusivity levels were also correlated with changes in the visual field and the degree of proptosis.
  
  
  CONCLUSIONS
  FA and mean diffusivity levels measured with the diffusion tensor imaging of the thyroid orbitopathy patients were affected. The changes in diffusion tensor imaging were also correlated with the ophthalmologic tests of the patients.
authors.affiliation: *Department of Ophthalmology, Kocaeli University, Faculty of Medicine, Izmit, Turkey; and †Department of Radiology, Kocaeli University, Faculty of Medicine, Izmit, Turkey.
authors.forename: Berna
authors.initials: B
authors.lastname: Özkan
authors.forename: Yonca
authors.initials: Y
authors.lastname: Anik
authors.forename: Büşra
authors.initials: B
authors.lastname: Katre
authors.forename: Özgül
authors.initials: Ö
authors.lastname: Altintaş
authors.forename: Mehmet
authors.initials: M
authors.lastname: Gençtürk
authors.forename: Nurşen
authors.initials: N
authors.lastname: Yüksel
mesh_terms: D000328:Adult; D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D049970:Graves Ophthalmopathy / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D009916:Orbital Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology