title: Presurgical brain mapping in epilepsy using simultaneous EEG and functional MRI at ultra-high field: feasibility and first results.
abstract: OBJECTIVE
  The aim of this study was to demonstrate that eloquent cortex and epileptic-related hemodynamic changes can be safely and reliably detected using simultaneous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) recordings at ultra-high field (UHF) for clinical evaluation of patients with epilepsy.
  
  
  METHODS
  Simultaneous EEG-fMRI was acquired at 7 T using an optimized setup in nine patients with lesional epilepsy. According to the localization of the lesion, mapping of eloquent cortex (language and motor) was also performed in two patients.
  
  
  RESULTS
  Despite strong artifacts, efficient correction of intra-MRI EEG could be achieved with optimized artifact removal algorithms, allowing robust identification of interictal epileptiform discharges. Noise-sensitive topography-related analyses and electrical source localization were also performed successfully. Localization of epilepsy-related hemodynamic changes compatible with the lesion were detected in three patients and concordant with findings obtained at 3 T. Local loss of signal in specific regions, essentially due to B 1 inhomogeneities were found to depend on the geometric arrangement of EEG leads over the cap.
  
  
  CONCLUSIONS
  These results demonstrate that presurgical mapping of epileptic networks and eloquent cortex is both safe and feasible at UHF, with the benefits of greater spatial resolution and higher blood-oxygenation-level-dependent sensitivity compared with the more traditional field strength of 3 T.
authors.affiliation: Department of Radiology and Medical Informatics, University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. frederic.grouiller@unige.ch.
authors.forename: Frédéric
authors.identifier: http://orcid.org/0000-0003-3445-5831
authors.initials: F
authors.lastname: Grouiller
authors.affiliation: Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Jorge
authors.affiliation: EEG and Epilepsy Unit, Department of Neurology, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pittau
authors.affiliation: Biomedical Imaging Research Center, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands.
authors.forename: Wietske
authors.initials: W
authors.lastname: van der Zwaag
authors.affiliation: Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland.
authors.forename: Giannina Rita
authors.initials: GR
authors.lastname: Iannotti
authors.affiliation: Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland.
authors.forename: Christoph Martin
authors.initials: CM
authors.lastname: Michel
authors.affiliation: EEG and Epilepsy Unit, Department of Neurology, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Serge
authors.initials: S
authors.lastname: Vulliémoz
authors.affiliation: Division of Neuroradiology, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Vargas
authors.affiliation: Department of Radiology and Medical Informatics, University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland.
authors.forename: François
authors.initials: F
authors.lastname: Lazeyras
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods*; D004566:Electrodes; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D009048:Motor Skills; D010100:Oxygen / Q000097:blood; D061214:Patient Safety; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: EEG–fMRI; Epilepsy; Presurgical mapping; Ultra-high field