 Introduction/Background A seizure is defined as a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain [1]. The International League Against Epilepsy (ILAE) defines epilepsy as having 1) at least two unprovoked seizures occurring more than 24 hours apart, 2) one unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures, occurring over the next 10 years, or 3) diagnosis of an epilepsy syndrome. Special Imaging Considerations In addition to the known benefits of using fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET for the localization of epileptogenic foci, there are known alterations of neurotransmitters and receptors in epilepsy [8]. Gamma aminobutyric acid is an inhibitory neurotransmitter known to be important in the regulation of epileptic activity and is evaluated using 11C-flumazenil [9]. Opioids can reduce the spread of electrical activity, can have an anticonvulsant effect [10], and can be evaluated with several tracers including 11C-carfentanil. Serotonin can also aEinstein Healthcare Network, Philadelphia, Pennsylvania. bPanel Chair, Montefiore Medical Center, Bronx, New York. cOhio State University, Columbus, Ohio. dDuke University School of Medicine, Durham, North Carolina; American College of Emergency Physicians. eOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada; Canadian Association of Radiologists. fUniversity of Michigan, Ann Arbor, Michigan. gMayo Clinic, Rochester, Minnesota. hUniversity of Kansas Medical Center, Kansas City, Kansas. iUniversity of California Los Angeles, Los Angeles, California; American Academy of Neurology. jUniversity of California San Diego Medical Center, San Diego, California. kOregon Health & Science University, Portland, Oregon. lNorthwestern University Feinberg School of Medicine, Chicago, Illinois; Neurosurgery expert.
Seizures and Epilepsy.  Introduction/Background A seizure is defined as a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain [1]. The International League Against Epilepsy (ILAE) defines epilepsy as having 1) at least two unprovoked seizures occurring more than 24 hours apart, 2) one unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures, occurring over the next 10 years, or 3) diagnosis of an epilepsy syndrome. Special Imaging Considerations In addition to the known benefits of using fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET for the localization of epileptogenic foci, there are known alterations of neurotransmitters and receptors in epilepsy [8]. Gamma aminobutyric acid is an inhibitory neurotransmitter known to be important in the regulation of epileptic activity and is evaluated using 11C-flumazenil [9]. Opioids can reduce the spread of electrical activity, can have an anticonvulsant effect [10], and can be evaluated with several tracers including 11C-carfentanil. Serotonin can also aEinstein Healthcare Network, Philadelphia, Pennsylvania. bPanel Chair, Montefiore Medical Center, Bronx, New York. cOhio State University, Columbus, Ohio. dDuke University School of Medicine, Durham, North Carolina; American College of Emergency Physicians. eOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada; Canadian Association of Radiologists. fUniversity of Michigan, Ann Arbor, Michigan. gMayo Clinic, Rochester, Minnesota. hUniversity of Kansas Medical Center, Kansas City, Kansas. iUniversity of California Los Angeles, Los Angeles, California; American Academy of Neurology. jUniversity of California San Diego Medical Center, San Diego, California. kOregon Health & Science University, Portland, Oregon. lNorthwestern University Feinberg School of Medicine, Chicago, Illinois; Neurosurgery expert.