Study On The Structure Of Visual Pathway White Matter In Children With Monocular Amblyopia By Diffusion Tensor Imaging

Objective:To investigate the development of children white matter with monocular anisometropic amblyopia with diffusion tensor imaging (DTI)and evaluate the underlying mechanism of monocular amblyopia.Methods:DTI was obtained from fifteen children with monocular anisometropic amblyopia and fourteen normally sighted children. Fractional anisotropy(FA)image of each subject was measured from the obtained original image data and formatted into a standardized template. The abnormal alba regions of patients with amblyopia were analyzed by Voxel-base morphometry(VBM)and compared all Voxel from the FA image of amblyopic and control groups,therefore to discuss the abnormal white matter of the monocular amblyopia.The optical radiations were rebuilded by tractography and regarded as regions of interest(ROIs),the average FA and Voxel number of Bilateral optical radiations were calculated and compared between two groups,and the optical radiations development of patients with amblyopia were discussed eventually.Results:The results of VBM analysis indicated that FA value of amblyopic group decreased in right occipital lobe,right inferior parietal lobule,temporal lobe and left insula but increased in bilateral thalamus, sub-lobar extra-nuclear white matter,frontal lobe,right superior frontal gyms,right lentiformnucleus and putamen.There were significant differences in average FA,total FA and voxel numbers between two groups in right OR but not in left OR.The total FA and voxel numbers of bilateral ORs were significantly different between the two groups except the average FA.It also demonstrated left-higher-than-right asymmetry of optical radiation in both amblyopic and control groups except average FA in control group.Conclusions:1,DTI can show the tract and abnormal change of white matter fibers of human visual pathway,so it can provide a new screening method for the study of the underlying mechanism in amblyopia.2,Through VBM analysis,morphologic changes were detected in the brain white matter of children with monocular anisometropic amblyopia,which suggested that the developmental abnormalities of nerve net cause main neural foundation of amblyopia. 3,Tractography showed less FA and voxel number in amblyopic children than in normal children,indicating that normal children have better development of the ORs.The underdevelopment of the both ORs might reflect the dysfunction of both visual pathways in children with monocular anisometropic amblyopia.