Device and method for determining an axial twist position of an electrode array for electrical impedance tomography

A method for the operation of an electrical impedance tomography device for a determination of an axial twist angle and/or of a torsion angle of an electrode array comprising a plurality of electrodes arranged on a thorax of a patient, the method comprising:

• feeding an electrical feed signal to two feeding electrodes of the electrodes in each measuring run with the two feeding electrodes varying cyclically in a measuring cycle comprised of a plurality of measuring runs;
• selecting measured signals at selected electrodes located opposite each of the feeding electrodes and acquiring the selected measured signals in each measuring run of a measuring cycle;
• determining a mean value (U56) of each selected measured signal (U56X) of each electrode pair of the respectively selected electrodes in each measuring run;
• determining a logarithmic ratio comprising
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• from the selected measured signals (U56) and the mean value (U56) for the selected electrodes, as a current signal trace;
• comparing the determined current signal trace with a comparison signal trace, wherein the comparison signal trace represents a signal trace of correctly positioned electrodes without axial twist angle or a torsion angle of the electrode array on the thorax, and an axial twist angle and/or a torsion angle of the electrode array on the thorax is determined on the basis of the comparison;
• generating a control signal which indicates at least one of the axial twist angle and the torsion angle of the electrode array on the thorax and providing the generated control signal as an output.