title: Ictal EEG-fMRI in localization of epileptogenic area in patients with refractory neocortical focal epilepsy.
abstract: OBJECTIVE
  To evaluate the usefulness of ictal electroencephalography (EEG)-combined functional magnetic resonance imaging ( MRI) (EEG-fMRI) in localizing epileptogenic zone in refractory neocortical focal epilepsy.
  
  
  METHODS
  From the EEG-fMRI database of our institution including 62 adult patients, 14 (age 18-46 years) experienced some ictal event during the test. Data were segmented into 10-s blocks, and the results were analyzed by contrasting each block to the contiguous 10-s block from the onset of seizure onward, in all cases. In seizures lasting >10 s (five cases), a supplementary analysis was performed, contrasting each block to a baseline condition, in the framework of the general linear model (GLM) of analysis. Regions of activations were compared to results from the different techniques performed during presurgical evaluation, such as SISCOM, positron emission tomography (PET), and invasive subdural EEG monitoring.
  
  
  RESULTS
  Regarding the structural MRI findings, nine cases presented some lesion, with blood oxygen level- dependent (BOLD) signal activation placed in the same location in eight of them (89%). SISCOM studies were performed in 11 patients; 5 were concordant with the increase in BOLD signal in a sublobar level, whereas in 3 cases the concordance was in a lobar level. Eleven patients underwent PET studies, being also concordant in a sublobar level in four of them and in a lobar level in four additional cases. Finally, invasive EEG evaluation was performed in three patients and all of them had the seizure-onset zone in the initial area of BOLD activation.
  
  
  CONCLUSIONS
  This study adds relevant information to support the integration of EEG-fMRI in the multidisciplinary presurgical workup in patients with refractory epilepsy.
authors.affiliation: Institute of Neurosciences, Hospital Clinic I Provincial, Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Sierra-Marcos
authors.forename: Iratxe
authors.initials: I
authors.lastname: Maestro
authors.forename: Carles
authors.initials: C
authors.lastname: Falcón
authors.forename: Antonio
authors.initials: A
authors.lastname: Donaire
authors.forename: Javier
authors.initials: J
authors.lastname: Setoain
authors.forename: Javier
authors.initials: J
authors.lastname: Aparicio
authors.forename: Jordi
authors.initials: J
authors.lastname: Rumià
authors.forename: Luis
authors.initials: L
authors.lastname: Pintor
authors.forename: Teresa
authors.initials: T
authors.lastname: Boget
authors.forename: Mar
authors.initials: M
authors.lastname: Carreño
authors.forename: Núria
authors.initials: N
authors.lastname: Bargalló
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D055815:Young Adult
keywords: EEG; Epilepsy; Functional imaging; MRI; Neuroradiology