title: Visualization of the eloquent motor system by integration of MEG, functional, and anisotropic diffusion-weighted MRI in functional neuronavigation.
abstract: BACKGROUND
  In this study, we visualized the eloquent motor system including the somatosensory-motor cortex and corticospinal tract on a neuronavigation system, integrating magnetoencephalography (MEG), functional magnetic resonance imaging (fMRI), and anisotropic diffusion-weighted MRI (ADWI).
  
  
  METHODS
  Four patients with brain lesions adjacent to the eloquent motor system were studied. Motor-evoked responses (MER) by finger-tapping paradigm were acquired with a 1.5-Tesla MR scanner, and somatosensory-evoked magnetic fields (SEF) by median nerve stimulation were measured with a 204-channel MEG system. In the same fMRI examination, ADWI and anatomic three-dimensional T1-weighted imaging (3-D MRI) were obtained. Activated areas of MER, estimated SEF dipoles, and the corticospinal tract on ADWI were coregistered to 3-D MRI, and the combined MR data were transferred to a neuronavigation system (functional neuronavigation). Intraoperative recording of cortical somatosensory-evoked potentials was performed for confirmation of the central sulcus.
  
  
  RESULTS
  Combination of fMRI and MEG enabled firm identification of the central sulcus. Functional neuronavigation facilitated extensive tumor resection, having the advantage of sparing the motor cortex and corticospinal tract in all cases.
  
  
  CONCLUSIONS
  The proposed functional neuronavigation allows neurosurgeons to perform effective and maximal resection of brain lesions, identifying and sparing eloquent cortical components and their subcortical connections. Potential clinical application of this technique is discussed.
authors.affiliation: Department of Neurosurgery, Hokkaido University, Sapporo, Japan.
authors.forename: Kyousuke
authors.initials: K
authors.lastname: Kamada
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Houkin
authors.forename: Fumiya
authors.initials: F
authors.lastname: Takeuchi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Ishii
authors.forename: Jun
authors.initials: J
authors.lastname: Ikeda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sawamura
authors.forename: Shinya
authors.initials: S
authors.lastname: Kuriki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Iwasaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016880:Anisotropy; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery; D038524:Diffusion Magnetic Resonance Imaging; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D009044:Motor Cortex / Q000473:pathology / Q000502:physiology*; D038361:Neuronavigation / Q000379:methods*; D011712:Pyramidal Tracts / Q000473:pathology / Q000502:physiology*; D013003:Somatosensory Cortex / Q000473:pathology / Q000502:physiology*