title: Magnetic resonance diffusion tensor imaging of optic nerve and optic radiation in healthy adults at 3T.
abstract: OBJECTIVE
  To investigate the diffusion characteristics of water of optic nerve and optic radiation in healthy adults and its related factors by diffusion tensor imaging (DTI) at 3T.
  
  
  METHODS
  A total of 107 healthy volunteers performed head conventional MRI and bilateral optic nerve and optic radiation DTI. The primary data of DTI was processed by post-processing software of DTI studio 2.3, obtaining fractional anisotropy value, mean diffusivity value, principal engine value, orthogonal engine value by measuring, and analyzed by the SPSS13.0 statistical software.
  
  
  RESULTS
  The bilateral optic nerve and optic radiation fibers presented green color in directional encoded color (DEC) maps and presented high signal in fractional anisotropy (FA) maps. The FA value of the left optic nerve was 0.598±0.069 and the right was 0.593±0.065; the mean diffusivity (MD) value of the left optic nerve was (1.324±0.349)×10(-3)mm(2)/s and the right was (1.312±0.350)×10(-3)mm(2)/s; the principal engine value (λ‖) of the left optic nerve was (2.297±0.522)×10(-3)mm(2)/s and the right was (2.277±0.526)×10(-3)mm(2)/s; the orthogonal engine value (λ⊥) of the left optic nerve was (0.838±0.285)×10(-3)mm(2)/s and the right was (0.830±0.280)×10(-3)mm(2)/s; the FA value of the left optic radiation was 0.636±0.057 and the right was 0.628±0.056; the mean diffusivity (MD) value of the left optic radiation was (0.907±0.103)×10(-3)mm(2)/s and the right was (0.889±0.125)×10(-3)mm(2)/s; the principal eigenvalue (λ‖) of the left optic radiation was (1.655±0.210)×10(-3)mm(2)/s and the right was (1.614±0.171)×10(-3)mm(2)/s; the orthogonal enginvalue (λ⊥) of the left optic radiation was (0.531±0.103)×10(-3)mm(2)/s and the right was (0.524±0.152)×10(-3)mm(2)/s. There was no obvious difference between the FA, MD, λ‖, λ⊥ of the bilateral optic radiation and the bilateral optic nerve (P>0.05) and no obvious difference between male and female group. The FA, MD, λ‖, λ⊥ of the bilateral optic radiation and the bilateral optic nerve had no obvious correlations to the age.
  
  
  CONCLUSIONS
  DTI is sensitive to the optic nerve and radiation and the relevant DTI parameters of the optic nerve and radiation are established preliminarily in this study.
authors.affiliation: Department of Radiology, the Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
authors.forename: Hong-Hong
authors.initials: HH
authors.lastname: Sun
authors.affiliation: Department of Radiology, the Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Radiology, the Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
authors.forename: Qiu-Juan
authors.initials: QJ
authors.lastname: Zhang
authors.affiliation: Department of Radiology, the Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
authors.forename: Zhi-Lan
authors.initials: ZL
authors.lastname: Bai
authors.affiliation: Department of Radiology, the Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
authors.forename: Ping
authors.initials: P
authors.lastname: He
keywords: diffusion tensor imaging; fractional anisotropy; magnetic resonance imaging; mean diffusivity; optic nerve; optic radiation