BOLD FMRI MAPPING OF ELOQUENT CORTICAL AREAS IN PATIENTS WITH BRAIN TUMOR USING INDEPENDENT PHYSIOLOGICAL PARAMETERS

Abstract

Introduction . Preoperative fMRI often shows a reduced BOLD response in the areas located perifocal to brain tumors caused by pathological vasoreactivity as a result of neurovascular uncoupling. The aim of this study was an accurate identification of the eloquent cortical areas near brain tumors by measuring vasoreactivity using the breath holding test. Material and methods. 23 patients with brain tumors located near eloquent cortical areas underwent fMRI mapping of the language and / or motor cortical areas depending on the location of the tumor. Breath hold test was also included, the design of which coincided with motor and language block paradigms. Results . A statistical dependency between motor, speech tasks and breath-hold BOLD-response was included into the BOLD analysis using coherence. fMRI activation maps generated by this method showed activation in the eloquent areas adjacent to brain tumors which were not detected by the standard analysis. This study shows that neurovascular uncoupling affects the accuracy of BOLD fMRI in brain tumors. Conclusion. The results of fMRI mapping can be partially improved by the incorporating vasoreactivity measurements into a standard analysis.