[Positron-emission tomography (PET) in epilepsy and extrapyramidal disorders]

Epilepsy means are frequent neurologic disorders caused by abnormal electric cerebral discharges of diverse origins. While most epileptic patients experience satisfactory suppression of seizures by drug regimens, a substantial number requires a neurosurgical intervention for improvement. This is particularly the case with epilepsy originating from the temporal lobe. 35 interventions for seizure disorders are actually carried out in Zurich each year. For the whole of Switzerland this could, depending on the criteria for an indication, mean from 150 to 1500 annual intervention. In any case an accurate localization of the epileptic focus is a prerequisite. Over the past years it has been shown that such foci and their surrounding exhibit often an abnormal pattern of glucose utilisation, which can be visualized by PET. In various centers for epileptic disorders worldwide, invasive preoperative neurophysiologic investigations are no longer used in view of these results. In extrapyramidal disorders (i.e. Parkinson's disease or Huntington's chorea), disturbances of basal ganglia occur. PET studies of these areas center around measurements of glucose metabolism, synthesis of dopamine and dopaminergic receptors. Such studies provide new insight into the pathophysiology of these diseases. They provide diagnostic clues in difficult cases and permit assessment of extent and progression of degeneration. Functional PET measurements also open new avenues for clinical pharmacology.