Assessment of Structural Maturation of the Optic Radiation in Children with Probalistic Tractography

Michael Dayan¹, Chris A. Clark¹

The optic radiation (OR) is a component of the visual pathway assumed to mature before 3 years old. This study aimed at evaluating diffusion tensor (DT) metrics within this tract, notably fractional anisotropy (FA) and radial diffusivity (RD), as a function of age, hemisphere and gender in children aged from 7 to 18. DT probabilistic tractography based on 10000 iterations was carried out for this purpose. A one sample t-test demonstrated a hemispheric dependence for RD (p < 0.01) but not for FA (p > 0.96). A multiple regression analysis did not show any gender effect for any DT indices. A significant age dependence was found for FA (p < 0.001) and RD (p < 0.04). These findings suggest an age-related effect from 7 to 18 years well after the OR is myelin mature, which suggests that maturational and/or developmental changes occur in the OR long after myelination.