The Role of Functional Neuroimaging in Pre-Surgical Epilepsy Evaluation

Abstract

The prevalence of epilepsy is about 1% and one-third of cases do not respond to medical treatment. In an eligible subset of patients with drug-resistant epilepsy, surgical resection of the epileptogenic zone is the only treatment that can possibly cure the disease. Non-invasive techniques provide information for the localization of the epileptic focus in the majority of cases, whereas in others invasive procedures are required. In the last years, non-invasive neuroimaging techniques, such as simultaneous recording of functional magnetic resonance imaging and electroencephalogram (EEG-fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), electric and magnetic source imaging (MSI, ESI), spectroscopy (MRS), have proved their usefulness in defining the epileptic focus. The combination of these functional techniques can yield complementary information and their concordance is crucial for guiding clinical decision, namely the planning of invasive EEG recordings or respective surgery. The aim of this review is to present these non-invasive neuroimaging techniques, their potential combination, and their role in the pre-surgical evaluation of patients with pharmaco-resistant epilepsy.

Pulse Artifact Detection in Simultaneous EEG–fMRI Recording Based on EEG Map Topography

“…The use of this technique is increasingly spreading across cognitive neuroscience (Debener et al 2006;Zotev et al 2014), sleep studies (Czisch et al 2004;Stern et al 2011), and resting state networks investigation (Britz et al 2010;Neuner et al 2014). Concerning epilepsy, EEGfMRI allows the characterization of focal and generalized epileptiform discharges and is typically applied for the presurgical localization of epileptic foci (Pittau et al 2014).…”

Reliability for non-invasive somatosensory cortex localization: Implications for pre-surgical mapping

“…Non-invasive pre-surgical functional mapping during planning can alleviate some of the challenges associated with invasive options, such as the Wada test and DCS, potentially leading to better patient outcomes.Procedures such as Page 5 of 22 A c c e p t e d M a n u s c r i p t magnetoencephalography (MEG), functional magnetic resonance imaging (fMRI), and navigated transcranial magnetic stimulation [2] are emerging as viable non-invasive alternatives for pre-surgical mapping [3], Given the invasive nature of procedures like DCS, there are inherent surgical riskswith severe health consequences [4]. The DCS procedure also requires compliance from the patient to complete the required tasks under challenging circumstances.This limits the applicability of the procedure to groups with challenges for compliance, such as young children and patients with neurological or cognitive deficits [5].…”

Propagating Neural Source Revealed by Doppler Shift of Population Spiking Frequency

“…Mapping the neural propagation and localizing the neural foci are usually difficult, but the identification of these neural sources and the study of the propagation have mechanistic, diagnostic, and therapeutic implications. For example, in the epilepsy clinic, patients with epileptiform propagation and multisite neural foci in temporal lobe are a frequent challenge and the mechanism is unknown (Pittau et al, 2014).…”