Which PET finding would indicate an active seizure?

• A. Seizure free
• B. Active seizure
• C. Normal metabolism
• D. Decreased glucose uptake

Answer: (B)

In PET imaging with FDG, the amount of glucose the brain uses reflects neuronal activity. During an active seizure, the affected brain region has markedly increased neuronal firing and energy demand, so it shows focal hypermetabolism (increased glucose uptake) on the scan. This is why the sign of an active seizure is increased glucose uptake in the seizured area. Seizure-free or baseline function would not show this ictal hypermetabolism, and decreased uptake would indicate reduced metabolic activity (often seen interictally or after a seizure), not an ongoing ictal event.