Nuclear imaging in epilepsy answers one spatial question: where does the seizure start, and can it be removed? The question becomes urgent when medication fails, because surgery is then the realistic chance of cure. Two techniques supply the localization that the workup is missing. Positron emission tomography (PET) with the glucose tracer fluorodeoxyglucose (FDG) reads brain metabolism between seizures, the interictal period. Single-photon emission computed tomography (SPECT) reads blood flow during a seizure, the ictal period. The seizure focus, the region where seizures begin, is what both are trying to locate.
Choose a route through the topic
Start with the drug-resistance note, then FDG-PET, then the MRI-negative note, and finish with SPECT. FDG-PET is the workhorse because it is available and well validated; ictal SPECT is conceptually powerful but logistically demanding, requiring tracer injection at the exact moment of a seizure in a monitored unit.
- Nuclear Imaging of Epilepsy — Drug-Resistant Epilepsy: what drug resistance means, why surgery needs an exact location, and the gap that EEG and MRI leave.
- Nuclear Imaging of Epilepsy — FDG-PET: the interictal hypometabolism signal, the seizure-free uptake protocol, temporal lobe lateralization, and the bilateral finding that rules surgery out.
- Nuclear Imaging of Epilepsy — MRI-Negative Epilepsy and PET-MRI Coregistration: how PET localizes when MRI shows no lesion, how it sizes an abnormality, and how the two images are registered to be read together.
- Nuclear Imaging of Epilepsy — SPECT: the ictal hyperperfusion signal, the injection timing it demands, and when it adds to PET.
Nuclear imaging sits inside the epilepsy family: begin at the Epilepsy hub for definitions and the overall map, and come here when the question turns surgical. PET and SPECT also appear in dementia and movement-disorder workups, but here the question is purely spatial.