Positron emission tomography (PETscanning). Recent technical developments (CT, MRI, grids) have dramatically altered our ability to identify the source of certain children’s seizures. Even newer techniques are beginning to improve our ability to study the pathophysiology (the chemical abnormalities) of the seizure areas themselves, rather than just the electrical or anatomic abnormalities. Progress in these areas is awesome.
Positron emission tomography (PET) scanning uses the same principles as CT scanning, but rather than using x-rays as the energy source, derives its images from radioactive particles (positrons), derived from chemicals injected into the body that reach the brain. Thus it is now possible to study, for example, how parts of the brain use glucose (sugar) by giving the body a form of glucose with the radioactive label. The portion of the brain actively using the glucose takes up more of the radioactivity and looks different in the picture produced. We are beginning to be able to study other chemicals and neurotransmitters associated with epilepsy. Positron emission tomography is a research technique we hope will eventually become useful in the clinical management of children with seizures.
Single photon emission computerized tomography (SPECT scanning). SPECT scanning, a variation of PET scanning, is less expensive and requires less equipment, but, at present, is far less precise in defining the abnormal area. However, since it is far faster than a PET scan, it may ultimately be better for identifying the changes that occur during a brief seizure. As the equipment improves, SPECT may become more useful and more widely available.