Comparative analysis of MR imaging, Ictal SPECT and EEG in temporal lobe epilepsy: a prospective IAEA multi-center study
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Background and purpose
MR imaging, ictal single-photon emission CT (SPECT) and ictal EEG play important roles in the presurgical localization of epileptic foci. This multi-center study was established to investigate whether the complementary role of perfusion SPECT, MRI and EEG for presurgical localization of temporal lobe epilepsy could be confirmed in a prospective setting involving centers from India, Thailand, Italy and Argentina.
We studied 74 patients who underwent interictal and ictal EEG, interictal and ictal SPECT and MRI before surgery of the temporal lobe. In all but three patients, histology was reported. The clinical outcome was assessed using Engel’s classification. Sensitivity values of all imaging modalities were calculated, and the add-on value of SPECT was assessed.
Outcome (Engel’s classification) in 74 patients was class I, 89%; class II, 7%; class III, 3%; and IV, 1%. Regarding the localization of seizure origin, sensitivity was 84% for ictal SPECT, 70% for ictal EEG, 86% for MRI, 55% for interictal SPECT and 40% for interictal EEG. Add-on value of ictal SPECT was shown by its ability to correctly localize 17/22 (77%) of the seizure foci missed by ictal EEG and 8/10 (80%) of the seizure foci not detected by MRI.
This prospective multi-center trial, involving centers from different parts of the world, confirms that ictal perfusion SPECT is an effective diagnostic modality for correctly identifying seizure origin in temporal lobe epilepsy, providing complementary information to ictal EEG and MRI.
KeywordsRefractory epilepsy Epilepsy surgery Ictal SPECT MRI EEG
The authors wish to thank the Nuclear Medicine Section, Division of Human Health, of the International Atomic Energy Agency (IAEA) for the efforts made to bring investigators together from around the world and for initiating, coordinating and financing this multi-center study (CRP: E1.30.21). The authors also wish to thank Dr. James Warwick, University of Stellenbosch, South Africa, and Dr. Gonca Civi, Cerrahpasa University, Turkey, for their interest in the study. The authors also wish to thank Mr. Bert Vanbilloen for the appreciated technical assistance.
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