title: Proposal for a new MEG-MRI co-registration: a 3D laser scanner system.
abstract: OBJECTIVE
  Co-registration between the head shape extracted from anatomical images that are obtained using a 3D digitizer is a non-negligible factor for magnetoencephalographic (MEG) utilization. The study aimed to propose a novel quick system based on a laser scanning technique involving a 3D laser scanner system that allows instant measurement while maintaining high accuracy and reproducibility.
  
  
  METHODS
  The measurement duration, accuracy, and reproducibility of the finger representations in response to tactile stimulation between the 3D laser scanner-based method and the conventional magnetic field digitizer-based method were compared in 11 healthy subjects. Day-to-day variance in target registration error (TRE), day-to-day and session-to-session variability in head position indicator error (HRE) and source localization accuracy were evaluated with visualization of the source estimation and analysis of variance (ANOVA).
  
  
  RESULTS
  Our proposed one-snapshot approach enabled 3D digitization measurements in <5s, and significantly reduced TRE, while mean HREs were a comparable level. Although there was less dramatic improvement of source localization, we found a significant reduction in session-to-session variability and day-to-day variance using our proposed method.
  
  
  CONCLUSIONS
  Our results clearly demonstrated improvements in speed, comfort, accuracy, and reproducibility when using our new MEG co-registration method.
  
  
  CONCLUSIONS
  A systematic improvement in MEG measurement will be beneficial for routine clinical use.
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. Electronic address: hironaga@med.kyushu-u.ac.jp.
authors.forename: Naruhito
authors.initials: N
authors.lastname: Hironaga
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hagiwara
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Ogata
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Hayamizu
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Urakawa
authors.affiliation: Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Tobimatsu
mesh_terms: D000328:Adult; D005260:Female; D006257:Head; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000592:standards; D007834:Lasers / Q000592:standards; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D015225:Magnetoencephalography / Q000379:methods* / Q000592:standards; D008297:Male; D015203:Reproducibility of Results
keywords: 3D laser scanner; Co-registration; Magnetoencephalography; Minimum norm estimate; Source localization; Tactile finger representations