ICTAL SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY IN OCCIPITAL LOBE SEIZURES

Purpose: Ictal single photon emission computed tomography (SPECT) has been evaluated as an adjunctive localizing technique in temporal lobe epilepsies and, to a lesser degree, in same extratemporal epilepsies. The purpose of this study was to determine whether occipital lobe seiz ures are associated with distinctive ictal cerebral blood perfusion (r CP) patterns. Methods: SPECT was used with the tracer Tc-99m HMPAO to image ictal rCP in 6 patients in whom clinical, EEG, and imaging data indicated occipital lobe seizures. Results: Two patterns of rCP were s een. Four patients had hyperperfusion that was restricted to the occip ital lobe, and two patients had hyperperfusion of the occipital lobe a nd the ipsilateral mesial temporal lobe, with hypoperfusion of the lat eral temporal lobe. The latter 2 patients had clinical and surface EEG evidence of temporal lobe involvement in the seizure discharge. Concl usions: Ictal rCP patterns in occipital lobe seizures are distinct fro m those in temporal lobe seizures and may vary according to whether or not ipsilateral temporal lobe structures are involved in the ictal di scharge.