Frontiers in Bioscience-Elite (FBE) is published by IMR Press from Volume 13 Issue 2 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
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Identification and localization of epileptogenic zone (EZ) is vital in patiets with medically-intractable focal epilepsy, who may be candidates for potentially curative resective epilepsy surgery. Presence of a lesion on magnetic resonance imaging (MRI) influences both diagnostic classification and selection for surgery. However, the implications for MRI-negative cases are not well-defined for such patients. Most of these patients undergo invasive long-term Electroencephalography recordings before a final decision regarding resection is possible. Recent developments in structural and functional neuroimaging which include quali-quantitative MRI, Positron Emission Tomography, Single Photon Emission Computed Tomography, and functional MRI have significantly changed presurgical epilepsy evaluation. Source analysis based on electrophysiological information, using either EEG or magnetoencephalography are also promising in order to noninvasively localize the EZ and to guide surgery in medically-intractable focal epilepsy patients that exhibit nonlesional MRI. This chapter aims to review the value of the combined use of structural and functional imaging techniques, and how this multimodal approach improves both selection of surgical candidates and post-operative outcomes in medically-intractable nonlesional focal epilepsy.