Diffusion property following functional hemispherectomy in hemimegalencephaly

Diffusion-tensor imaging (DTI), a unique magnetic resonance technique for analysis of diffusion-anisotropy of the brain, can identify subtle white matter changes in vivo. To investigate changes of truncated neurofibers, DTI was conducted prior to and following functional hemispherectomy in a female infant for refractory epilepsy associated with hemimegalencephaly. Anisotropy of the amputated pyramidal tract decreased relative to the unaffected side after surgery, which reflects secondary degeneration in neurofibers. In DTI applied to infants, differentiation between developmental changes and changes associated with the current phenomenon must be evaluated cautiously. Standardization of diffusion-tensor analysis of developmental change is desirable.