Abstracts

The usefulness and prognostic value of Subtraction Ictal SPECT Co-registered to MRI (SISCOM) for presurgical evaluation in intractable partial onset epilepsy has been well established. However, the prognostic significance of bitemporal hyperperfusion on SISCOM has not been studied in patients with intractable temporal lobe epielpsy. Our previous study with smaller number of patients did not show significant difference in surgical outcome between unilateral vs. bilateral temporal hyperperfusion group. We included patients who met the following criteria: 1) patient underwent presurgical evaluation including video-EEG monitoring, brain MRI, ictal/interictal SPECT, formal neuropsyhcologic testing and Wada test; 2) SISCOM result was concordant with the epileptogenic foci determined by scalp EEG-Video monitoring and brain MRI; 3) patient subsequently underwent unilateral temporal lobectomy; 4) patient was followed at least 1 year post-operatively. Surgical outcome using Engel[apos]s classification, clinical and electrophysiologic data was compared with regard to the presence of bitemporal hyperperfusion on SISCOM. Forty-one patients (M 20, F 21; age range 10-61, mean 34.4 yrs) were included in our study. Twenty-seven patient showed unilateral temporal hyperperfusion on SISCOM while 14 patients had bitemporal hyperperfusion. Patients[apos] age, sex, duration of seizures were comparable between two groups. History of complex febrile seizure was more frequent in unilateral temporal group (10/27 (37%) vs. 1/14 (7%)). Ictal EEG was more often unlocalizing in bitemporal group (12/14, 86%) than unilateral group (12/27, 44%). Surgical outcome was significantly worse in patients with bitemporal hyperperfusion than unilateral (seizure free at 1 year, 6/14 (43%) vs. 21/27 (78%); p = 0.03, Fisher[apos]s Exact Test). Our data suggest that bitemporal hyperperfusion on SISCOM may be a signficant prognostic factor for surgical outcome in temporal lobe epilepsy patients. More careful presurgical evaluation including intracranial EEG may be required for this group of patients. (Supported by National Epifellows Foundation)