Multimodal cranial neuronavigation: Direct integration of functional magnetic resonance imaging and positron emission tomography data: Technical note

OBJECTIVE: This is the first report of the direct integration of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) d ata into cranial neuronavigation. METHODS: In a patient with a left precentral oligodendroglioma (World Healt h Organization Grade III), the Zeiss MKM system (Carl Zeiss Co., Oberkochen , Germany) was used for navigation based on thin-slice, T1-weighted, contra st-enhanced magnetic resonance imaging (MRI) scans. fMRI and methionine PET data were integrated by landmark matching, with reference to skin fiducial s. RESULTS: The inaccuracy of the image fusion between fMR1 and T1-weighted MR I data was 1.7 mm, that between PET and T1-weighted MRI data was 4.3 mm, an d that for the subsequent registration of the navigation was 1.2 mm. The co rrect fMRI localization of the precentral gyrus was intraoperatively verifi ed by cortical somatosensory evoked potential (phase-reversal) monitoring. Although the tumor was not clearly defined in the MRI scans, [C-11]methioni ne PET demonstrated a clear tumor border, enabling us to achieve gross tota l tumor removal without postoperative functional deficits. CONCLUSION: Functional neuronavigation permits observation and preservation of relevant brain areas. Other functional areas (such as shortterm memory areas) that can be detected only by fMRI might also warrant future monitori ng. The simultaneous integration of fMRI and PET data adds a new dimension to cranial neuronavigation, enabling the observation of tumors in relation to functional cortical areas (in our case, the motor strip).