Interictal PET in Epilepsy: Lesion is Usually, but not always, Hypometabolic
From: Juhasz C, et al. Ann Neurol 2000;48:88-96

Surface location of electrodes with seizure onset (yellow), early seizure spread (purple), and no early ictal involvement (white) compared with the location of underlying areas of hypometabolism (red), who had a left temporal seizure onset propagating to the frontal cortex. Electrodes with a black cross were designated as overlying a metabolic border zone. The numbers represent electrode numbering of the corners of the grid.

This electrocorticographic sample demonstrates the buildup of a seizure at the inferior-anterior portion of the grid (with maximum amplitude at electrodes 17 and 18; arrowhead), which mostly represents electrodes over metabolic border zones. After the sudden discontinuation of the original ictal activity, high-amplitude semirhythmic activity developed at the superior-anterior corner of the grid, which later evolved to rhythmic spiking (not shown) eventually involving a larger field.
The epileptogenic temporal cortex was removed, but the frontal cortex receiving early spread was not entirely resected because of the proximity of the motor speech area. After temporary (2 months) seizure freedom, seizures originating from the frontal region recurred.