title: Dual array EEG-fMRI: An approach for motion artifact suppression in EEG recorded simultaneously with fMRI.
abstract: OBJECTIVE
  Although simultaneous recording of EEG and MRI has gained increasing popularity in recent years, the extent of its clinical use remains limited by various technical challenges. Motion interference is one of the major challenges in EEG-fMRI. Here we present an approach which reduces its impact with the aid of an MR compatible dual-array EEG (daEEG) in which the EEG itself is used both as a brain signal recorder and a motion sensor.
  
  
  METHODS
  We implemented two arrays of EEG electrodes organized into two sets of nearly orthogonally intersecting wire bundles. The EEG was recorded using referential amplifiers inside a 3T MR-scanner. Virtual bipolar measurements were taken both along bundles (creating a small wire loop and therefore minimizing artifact) and across bundles (creating a large wire loop and therefore maximizing artifact). Independent component analysis (ICA) was applied. The resulting ICA components were classified into brain signal and noise using three criteria: 1) degree of two-dimensional spatial correlation between ICA coefficients along bundles and across bundles; 2) amplitude along bundles vs. across bundles; 3) correlation with ECG. The components which passed the criteria set were transformed back to the channel space. Motion artifact suppression and the ability to detect interictal epileptic spikes following daEEG and Optimal Basis Set (OBS) procedures were compared in 10 patients with epilepsy.
  
  
  RESULTS
  The SNR achieved by daEEG was 11.05±3.10 and by OBS was 8.25±1.01 (p<0.00001). In 9 of 10 patients, more spikes were detected after daEEG than after OBS (p<0.05).
  
  
  CONCLUSIONS
  daEEG improves signal quality in EEG-fMRI recordings, expanding its clinical and research potential.
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Ilana
authors.initials: I
authors.lastname: Klovatch-Podlipsky
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel. Electronic address: Tomergazit@gmail.com.
authors.forename: Tomer
authors.initials: T
authors.lastname: Gazit
authors.affiliation: EEG and Epilepsy Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Firas
authors.initials: F
authors.lastname: Fahoum
authors.affiliation: School of Mathematics, Tel Aviv University, Israel.
authors.forename: Boris
authors.initials: B
authors.lastname: Tsirelson
authors.affiliation: EEG and Epilepsy Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Israel; Sackler School of Medicine, Tel Aviv University, Israel.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Kipervasser
authors.affiliation: Pediatric Epilepsy Unit, Tel Aviv Sourasky Medical Center, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Kremer
authors.affiliation: Pediatric Neurology Unit, Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Bruria
authors.initials: B
authors.lastname: Ben-Zeev
authors.affiliation: Schneider Children's Medical Center of Israel, Petach Tikvah, Israel.
authors.forename: Hadassah
authors.initials: H
authors.lastname: Goldberg-Stern
authors.affiliation: Department of Radiology, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Orna
authors.initials: O
authors.lastname: Eisenstein
authors.affiliation: Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Harpaz
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Ory
authors.initials: O
authors.lastname: Levy
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Kirschner
authors.affiliation: EEG and Epilepsy Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Israel; Sackler School of Medicine, Tel Aviv University, Israel.
authors.forename: Miriam Y
authors.initials: MY
authors.lastname: Neufeld
authors.affiliation: Department of Neurosurgery, David Geffen School of Medicine and Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA; Functional Neurosurgery Unit, Tel-Aviv Medical Center, Israel.
authors.forename: Itzhak
authors.initials: I
authors.lastname: Fried
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel; Sackler School of Medicine, Tel Aviv University, Israel; School of Psychological Sciences, Tel-Aviv University, Israel; Sagol School of Neuroscience, Tel-Aviv University, Israel.
authors.forename: Talma
authors.initials: T
authors.lastname: Hendler
authors.affiliation: Tel-Aviv Center for Brain Functions, Whol Institute for Advance Imaging, Tel Aviv Sourasky Medical Center, Israel; Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Mordekhay
authors.initials: M
authors.lastname: Medvedovsky
mesh_terms: D000293:Adolescent; D000328:Adult; D016477:Artifacts; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002648:Child; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004569:Electroencephalography / Q000592:standards*; D005260:Female; D059907:Functional Neuroimaging / Q000592:standards*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D055815:Young Adult
keywords: Artifact; Ballistocardiogram; EEG; ICA; fMRI