[Electrosubcorticography and impedance in the computer tomographic biopsy of brain tumors]

During 15 stereotaxic biopsies of brain tumors along 26 trajectories of introduction of the bioptic cannula, the brain tissue impedance was measured many times together with the recording of an electrosubcorticogram from the same points. Electrophysiological examination yields mutually complementing and authentic information concerning the boundaries of the pathological process and the condition of the perifocal brain matter, which improves the results of stereotaxic biopsy by increasing its informativeness. The impedance contours on the whole reflect the changes of the brain matter X-ray density, but there may be a discrepancy between these data in some cases since impedance is a more dynamic characteristic.