Brain Volumetric Differences in Pediatric Epilepsy: A Focus on Genetic Etiology

Purpose: To investigate brain volumetric characteristics in children with epilepsy of a genetic etiology, we retrospectively analyzed magnetic resonance imaging (MRI) volumetric data from three groups: children with epilepsy of a genetic etiology (n=25), children with epilepsy of a non-genetic etiology (n=25), and healthy controls (n=23). Methods: We analyzed the brain volume, mean surface areas, and cortical thickness of those children of each group using FreeSurfer. Among them whom underwent follow-up brain MRI (n=11), we investigated age-related serial changes in brain volume and cortical thickness. Results: As a result, total brain, total grey matter (GM), cortical and subcortical GM, white matter (WM), cerebellar and cerebellar GM volumes were considerably smaller in the genetic group than in the other groups. In the genetic group, a marked reduction was observed in the surface area measurements across brain regions associated with higher brain function. The mean cortical thickness was not significantly different among the three groups. Longitudinal MRI studies (n=11) revealed age-related brain volume changes; both genetic and non-genetic groups showed increases in total brain, subcortical GM, and WM volume. The genetic group showed a decrease (R=–0.42, P=0.13) over time, whereas non-genetic group showed an increase in cortical GM volume (R=0.77, P=0.009). Conclusion: Quantitative brain MRI volumetry can offer insight into the genetic etiology of pediatric epilepsy. When reductions in total brain volume or a gradual decline in gray matter are observed, genetic testing may be considered to evaluate potential genetic causes.