Bilateral diffusion tensor abnormalities of temporal lobe and cingulate gyrus white matter in children with temporal lobe epilepsy

Purpose: Bilateral diffusion tensor imaging (DTI) abnormalities have been reported in the white matter associated to the hippocampus in adults with mesial temporal lobe epilepsy (TLE). In children with a shorter duration of epilepsy, such changes may not have yet emerged. The aim of this study was to investigate interictal changes in the temporal lobe white matter (TLWM) and cingulate gyrus white matter (CGWM) of children with TLE using DTI. Methods: DTI was performed in eight children with TLE and 10 healthy, age-matched controls. Fractional anisotropy (FA), trace, parallel (λ_||) and perpendicular (λ_⊥) diffusivity were calculated for a volume of interest in the TLWM and CGWM on the seizure focus side and the contralateral side. Data were compared for differences between sides for patients and between patients and controls. Results: There was no significant difference in FA, trace, λ_|| and λ_⊥ between TLWM and CGWM on the seizure focus side versus the contralateral side in TLE patients. Increased diffusivity, λ_|| and λ_⊥ within the TLWM and CGWM were found in TLE patients compared to controls, but no significant difference in FA was seen. Conclusions: Bilaterally increased diffusivity, λ_|| and λ_⊥ in the white matter in children with TLE may be related to seizure induced functional or structural changes. The preserved FA in our pediatric cohort is in contrast to the reduced FA in the white matter of adults with TLE and may relate to differences in the duration of epilepsy or in the vulnerability of white matter to seizures.