Abstracts

There is evidence suggesting that the clinical utility of ictal SPECT in selection of cases to surgery should be reevaluated. For example, in patients with bilateral temporal spikes the rate of correct lateralization of ictal SPECT in MTLE-HS is only 55%. The aim of this study was to assess the clinical utility of the ictal SPECT in MTLE-HS. To address this question, we perform a prospective and randomized study, comparing presurgical diagnostic strategies with and without ictal SPECT in 206 patients with MTLE-HS submitted to presurgical evaluation. Patients with suspected MTLE-HS evaluated between January 2002 and June 2004, were evaluated for eligibility to participate. Informed written consent was obtained before randomization. The patients were randomly allocated in two groups. The strategies used to investigate MTLE-patients candidates to surgery were similar except by interictal and ictal SPECT. The workup in the SPECT group included clinical history and neurological examination, VEEG monitoring, neuropsychological examination, and Wada test for memory and speech representation. Neuroimaging included high-resolution MRI, and ictal and interictal SPECT scans. In the no-SPECT group, patients were submitted to the same protocol described above, excluding interictal and ictal SPECT. The primary study endpoints were the percentage of operated cases, and the rate of patients who were submitted to semi-invasive or invasive investigation. Secondary endpoints included: Engel[acute]s classification after surgery, total in-hospital costs, and length of stay. Were included 206 patients in the study. All patients had refractory TLE and the ictal SPECT study was realized during a CPS. The mean age at enrolment was 38.3 +/- 9.0. The epilepsy duration was 21 years. Mesial temporal lobe region was the epileptogenic zone in all patients. There were no difference in primary and secondary endpoints between groups. The percentage of patients submitted to surgery and to invasive investigation (foramen ovale and depth electrodes) was very similar between groups (p=1.0). Our findings indicate that, in our hands, the ictal SPECT does not cause significant impact in decision making about eligibility for surgery or need for invasive investigation in patients with MTLE-HS. In conclusion, although ictal SPECT has been considered very useful in presurgical evaluation of extratemporal epilepsy, there is uncertainty if ictal SPECT can provide real benefits to clinical decision making in patients with MTLE-HS. (Supported by FAPESP/CINAPCE program, CAPES, CnPq.)