ICTAL CEREBRAL BLOOD-FLOW IN SEIZURES ORIGINATING IN THE POSTEROLATERAL CORTEX

In selecting patients for epilepsy surgery, ii is important to disting uish mesial temporal seizures from seizures originating in the postero lateral cortex. We studied ictal cerebral perfusion in five patients w ith complex partial seizures with clear posterior EEG ictal onsets and clinical seizure semiology suggesting seizure origin in the posterola teral cortex. Methods: Ictal SPECT was Performed during video EEG moni toring using Tc-99m-HMPAO as a cerebral perfusion tracer and a rotatin g gamma camera to acquire images. Results: Three patterns of ictal hyp erperfusion were seen: pattern A = temporoparieto-occipital junction e xtending into the lateral temporal cortex, involving the mesial tempor al cortex and basal ganglia to a lesser degree and a small area of hyp erperfusion in the contralateral parietal cortex (two patients); patte rn B = pattern A but with no hyperperfusion of the mesial temporal cor tex (one patient); and pattern C = localized hyperperfusion in the are a of the temporoparieto-occipital junction (two patients), Conclusion: Our results suggest distinct patterns of ictal perfusion in seizures with posterolateral ictal EEG onsets. Ictal SPECT may be useful in dis tinguishing such seizures.