Perfusion SPECT, SISCOM and PET 18F-FDG in the assessment of drug-refractory epilepsy patients candidates for epilepsy surgery

Abstract

AimsBrain perfusion SPECT (ictal–interictal), SPECT images and subtraction ictal SPECT coregistered to MRI (SISCOM) and 18F-FDG-PET (interictal) play an important role in the pre-surgical diagnosis of patients with medically refractory epilepsy.This study aimed to establish the reproducibility of visual ictal–interictal SPECT and SISCOM analysis altogether with the capacity of SPECT, SISCOM and PET to determine the epileptogenic zone. Material and methods99mTc-HMPAO SPECT ictal–interictal and SISCOM (Analyze 7.0) were performed on 47 refractory epilepsy patients (24 F, 19–60 yrs). In 13 patients, SISCOM was also performed using a new programme (Focus DET). Ictal–interictal SPECT and SISCOM images were analyzed independently by two nuclear medicine physicians (observers 1 and 2). Kappa concordance coefficient was used to evaluate the reproducibility. In sixteen patients, SPECT, SISCOM and PET findings were compared with the resected area during the surgery, and surgical outcome using Engel scale or with the stereo EEG-(SEEG). ResultsThe ictal–interictal SPECT interobserver agreement was 91%, Kappa index 0.86, SISCOM (Analyze 7.0) interobserver agreement percentage was 82%, Kappa index 0.80, Analyze 7.0 showed a higher inconclusive results than visual SPECT analysis. SISCOM FocusDET interobserver agreement was 92%, Kappa index 0.87, with lower inconclusive results than Analyze 7.0. SPECT, SISCOM and PET combined findings identified 87% seizure onset zone: 79% temporal, 26% parieto-temporal and 7% frontal. ConclusionsIctal–interictal SPECT and SISCOM showed a high reproducibility in this sample of patients with drug-refractory epilepsy. SPECT, SISCOM and PET combined findings improved detection of epileptogenic zone in comparison with the individual assessment.