SPECT and PET Imaging in epilepsy: principles and clinical applications

RESUMO

Functional neuroimaging with single photon emission computed tomography (SPECT) and positron emission tomography (PET) has documented several perfusion, metabolic and neurochemical dysfunctions in a variety of neurological conditions. In the presurgical workup of medically intractable epilepsies, a group of investigations is included to ascertain the lacalization of the epileptogenic zone. The aim of the present study is to review the principles and revelant investigations about the application of SPECT and PET to the epilepsies. We reviewed the physiological aspects of cerebral blood flow during seizures, pharmacological characteriristics of radiopharmaceuticals, and clinical applications of SPECT in the investigation of epileptic seizures, and provided a review of the main clinical contributions of PET in epilepsy. SPECT and PET have an important and complementary role in the presurgical evaluation as well as in pathophysiological researchs about epilepsy. Both may evaluate the ictal and interictal states of cerebral functions, playing a particular role in those patients who present with inconclusive studies of both Magnetic Resonance Imaging and the Video - EEG monitoring. Additionally, they may avoid or guide invasive neurophysiological studies, and help suggest the localization of the epileptogenic zone in those cases with extensive or multiple lesions