The use of positron emission tomography in the clinical assessment of epilepsy.

Positron emission tomography (PET) of local cerebral glucose utilization is highly sensitive in detecting epileptogenic regions that correspond to electrographic localization in patients with epilepsy. In medically refractory temporal lobe epilepsy for which surgical resection of the epileptogenic zone is a therapeutic option, the application of PET enables more than 50% of adults and older children to be successfully operated on without the necessity for chronic intracranial electrographic monitoring. In infants with intractable infantile spasms and various types of partial epilepsy, PET has uncovered focal areas of cortical dysplasia and other anatomic abnormalities, which, after resection, have resulted in cessation of seizures and developmental improvement. The distribution of PET abnormality is in excellent agreement with the extent of the epileptogenic zone as determined by intraoperative electrocorticography, thus avoiding the necessity for chronic intracranial electrographic monitoring in 90% of these infants. As a result of PET, the preoperative evaluation of intractable epilepsy in both adults and children has become less invasive and less costly.