Integration of functional magnetic resonance imaging supported by magnetoencephalography in functional neuronavigation

Abstract

OBJECTIVE: In this study, the intraoperative visualization of functional data provided by functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) leading to functional neuronavigation is demonstrated in surgery around the motor strip. METHODS: In seven patients with lesions adjacent to the central region, fMRI was performed with a 1.5-Tesla magnetic resonance system, using axial echo-planar imaging with a motor and a sensory task. Somatosensory and motor evoked fields were recorded with a biomagnetometer. fMRI and MEG were matched to an anatomic three-dimensional magnetic resonance image set by a contour fit. Then this three-dimensional image data set was transferred to the navigation microscope and displayed in the eyepieces of the microscope during surgery. Additionally, intraoperative recording of somatosensory evoked potentials was performed for verification of the central sulcus. RESULTS: In all cases, the projection of fMRI and MEG data into the operating viewing field allowed easy identification of the central region, which was confirmed by phase reversal of somatosensory evoked potentials in each case. fMRI and MEG measurements yielded corresponding results in each patient. CONCLUSION: Functional neuronavigation with integration of fMRI and MEG allows the fast identification of eloquent brain areas. The widespread availability of fMRI will result in a broad availability of functional neuronavigation, which will, in turn, contribute to the successful surgery of lesions in eloquent brain areas with lower morbidity.