Corpus callosum agenesis and epilepsy: PET findings

Positron emission tomography (PET) with 2-deoxy-2[18F]fluoro-D-glucose (FDG) was used to study 9 children who demonstrated complete or partial agenesis of the corpus callosum (ACC) on magnetic resonance imaging (MRI). Of the 7 patients with epilepsy, FDG-PET clearly localized areas of cortical metabolic abnormality in 6 patients; in 5 of these, localization of the metabolic abnormalities on PET corresponded to electroencephalographic localization of epileptogenicity. MRI documented focal cortical abnormalities in only 2 of the 7 children with epilepsy. In 1 patient, the abnormality observed on MRI was confined to a frontal lobe, whereas the FDG-PET study revealed hypometabolism of the entire hemisphere. One patient with infantile spasms exhibited bilateral multifocal epileptiform discharges on electroencephalography, whereas both the PET and MRI revealed only left hemispheral cortical abnormalities. Another patient with infantile spasms had prominent brainstem glucose metabolic activity on FDG-PET in the absence of any MRI or PET cortical abnormality. Two children underwent surgery because of refractory seizures; the resected cortical tissue in both patients consisted of cortical microdysgenesis. Seizure control improved significantly in both patients. FDG-PET studies in the 2 highest functioning patients (i.e., only minor learning disabilities and no epilepsy) did not reveal any focal cortical hypometabolism; therefore, there appears to be an association between the presence of focal metabolic abnormalities on PET and the presence of seizures in ACC patients.(ABSTRACT TRUNCATED AT 250 WORDS)