Functional magnetic resonance is a noninvasive method used for mapping cortical functions. Within 2003–2005 we compared fMRI and electric cortical stimulation results of primary motor area in 14 patients with tumors located in the central motor area. During fMRI the primary sensorimotor area was activated by rhythmic touching the thumb to the other fingers. The fMRI results were gained on the significancy levels P<0.001 without correction and P<0.05 FWE corrected. Eight patients (57 %) demonstrated good correlation of both function localizing methods. In 3 patients (21.5 %) the equality was only partial, with finding one positive motor response to cortical stimulation gained out of the BOLD signal. Three patients (21.5 %) showed full mismatch of results of both methods. The sensitivity of fMRI for localizing the brain cortex with a motor function was 63 %. Retrospective evaluation of morphological MR scans has demonstrated that mismatch of the results was probably caused by local depression of BOLD signal by collateral oedema and/or infiltrative growth of the tumor.

        Key words: functional magnetic resonance, electric cortical stimulation, eloquency, neuronavigation