A 27-year-old female presented with repeated seizures. As the left frontal lobe volume was enlarged in comparison with the right frontal lobe, hemimegalencephaly was suggested. Abnormal white matter fiber tracts running from the left frontal lobe to the fornix and hippocampus were found on diffusion tensor imaging (DTI). We performed quantitative measurements of brain volume and confirmed hemimegalencephaly. DTI and MRI-based volumetry techniques could be useful to objectively diagnose hemimegalencephaly.
