Visualization of the eloquent motor system by integration of MEG, functional, and anisotropic diffusion-weighted MRI in functional neuronavigation.
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.
Kamada
Kyousuke
K
Department of Neurosurgery, Hokkaido University, Sapporo, Japan.
Houkin
Kiyohiro
K
Takeuchi
Fumiya
F
Ishii
Nobuaki
N
Ikeda
Jun
J
Sawamura
Yutaka
Y
Kuriki
Shinya
S
Kawaguchi
Hideaki
H
Iwasaki
Yoshinobu
Y
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*