CORPUS-CALLOSUM AGENESIS AND EPILEPSY - PET FINDINGS

Positron emission tomography (PET) with 2-deoxy-2[18]fluoro-D-glucose (FDG) was used to study 9 children who demonstrated complete or partia l agenesis of the corpus callosum (ACC) on magnetic resonance imaging (MRI). Of the 7 patients with epilepsy, FDG-PET clearly localized area s of cortical metabolic abnormality in 6 patients; in 5 of these, loca lization of the metabolic abnormalities on PET corresponded to electro encephalographic localization of epileptogenicity. MRI documented foca l 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 mult ifocal epileptiform discharges on electroencephalography, whereas both the PET and MRI revealed only left hemispheral cortical abnormalities . Another patient with infantile spasms had prominent brainstem glucos e metabolic activity on FDG-PET in the absence of any MRI or PET corti cal abnormality. Two children underwent surgery because of refractory seizures; the resected cortical tissue in both patients consisted of c ortical microdysgenesis. Seizure control improved significantly in bot h patients. FDG-PET studies in the 2 highest functioning patients (i.e ., only minor learning disabilities and no epilepsy) did not reveal an y focal cortical hypometabolism; therefore, there appears to be an ass ociation between the presence of focal metabolic abnormalities on PET and the presence of seizures in ACC patients. Furthermore, the diagnos is of ACC in children with intractable epilepsy should not preclude an aggressive approach for possible epilepsy surgery.