When is positron emission tomography really necessary in epilepsy diagnosis?

Positron emission tomography can be used for localization of epileptic foci, and preoperative functional mapping. Rapid improvements in magnetic resonance imaging, however, have restricted the need for positron emission tomography to a minority of patients who have unrevealing magnetic resonance imaging scans. Positron emission tomography will continue to be of value in investigations of the pathophysiology of seizure disorders.