DELINEATION OF BRAIN TUMORS BY STEREO-IMPEDO-ENCEPHALOGRAPHY (SIEG)

  • 1 January 1978
    • journal article
    • research article
    • Vol. 24  (1) , 3-13
Abstract
The SIEG technique which is routinely used during stereotactic investigations of brain tumors was described. Using Talairach''s stereoencephalographic electrodes, the brain tissue impedance was measured along the probe trajectory with a 4 electrode impedancemeter (0.25 mA; 5 KHz). The impedance profile provided a good pattern of the brain structures which are crossed. In pathological areas, the impedance significantly decreases as well in gliomas as in edema. Cysts and CSF spaces decreased the recorded impedance. Metastases and meningiomas increase the impedance. SIEG appears to be a sharp method for stereotactic delineation of the brain tumors. A larger series as well as the real-imaginary decomposition of the impedance are needed for a better selectivity of the method.