title: [MR DTI and DTT study on the development of optic radiation in patients with anisometropia amblyopia].
abstract: OBJECTIVE
  To evaluate the development of optic radiations (ORs) in patients with anisometropia amblyopia using magnetic resonance diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT), and to explore possible mechanism of pathogenesis of amblyopia.
  
  
  METHODS
  Brain scan was performed with 3.0 Tesla scanner on 8 patients with anisometropia amblyopia and 15 control subjects with normal sights. The fractional anisotropy (FA) values, the apparent diffusion coefficient (ADC) values, the numbers of neural fiber bundle of ORs, and the voxel numbers of ORs were compared between the patients with anisometropia amblyopia and those with normal sights and between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia.
  
  
  RESULTS
  No differences in the FA values, the ADC values, the numbers of neural fiber bundle of ORs and the voxel numbers of ORs were found between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia (P > 0.05). Significant decreases in the FA values and the voxel numbers of ORs were found in the patients with amblyopia compared with the controls (P < 0.05). No differences in the voxel numbers of both ORs in the anterior parts were found between the patients with amblyopia and the controls (P > 0.05). However, the patients with amblyopia had more voxel numbers of ORs in the posterior parts than the controls (P < 0.05). The differences in the ADC values and the numbers of neural fiber bundle of ORs between the patients with amblyopia and the controls were not significant (P > 0.05).
  
  
  CONCLUSIONS
  The compactability, integrity and directivity of ORs decrease in patients with anisometropia amblyopia. The projection of OR fibers is abnormal. The ORs are underdeveloped, especially in the posterior parts, although no abnormal morphologic changes occur. The DTI and DTT can detect the underdevelopment of optic radiations in patients with anisometropia amblyopia indirectly.
authors.affiliation: Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Song
authors.forename: Shun
authors.initials: S
authors.lastname: Qi
authors.forename: He-Han
authors.initials: HH
authors.lastname: Tang
authors.forename: Feng-Juan
authors.initials: FJ
authors.lastname: Yu
authors.forename: Long-Qian
authors.initials: LQ
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000150:complications / Q000175:diagnosis*; D015858:Anisometropia / Q000150:complications / Q000175:diagnosis*; D016022:Case-Control Studies; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009900:Optic Nerve / Q000473:pathology*; D014795:Visual Pathways / Q000473:pathology