Anatomical Assessment of the Optic Radiation in Children with Probabilistic Tractography

Michael Dayan¹, Chris A. Clark¹

Temporal lobectomy, a surgical procedure notably carried out in children affected by intractable epilepsy, may be associated with visual field defects if the optic radiation (OR) is damaged. The lack of data in children on the spatial dimensions and location of this pathway with highly variable anterior aspect, Meyers loop (ML), lead us to reconstruct the OR in children in the age range 7 to 18 with probabilistic tractography. The segmentation was assessed by computing two reference anatomical distances, the distance from ML to the temporal pole (ML-TP) and to the occipital pole (ML-OP), and comparing them with other tractography and dissection studies in adults. A one sample t-test showed a hemispheric dependence for ML-TP and ML-OP (p < 0.02) and a multiple regression analysis demonstrated a gender dependence but no age effect. The distances reported in this study were similar to tractography and dissection studies in adults. These data and the statistically significant dependence on gender and hemisphere are envisaged to be relevant when considering neurosurgical planning for temporal lobectomy in children.