Comparison of impedance and ultrasound spectroscopy in investigations of ischaemia caused alterations in organ tissue

During ischemia the tissue of organs undergoes progressive changes leading, finally, to a condition where resuscitation is no longer possible. Monitoring these alterations is of great practical interest for evaluating the probability of successful revival of the organ. Damage of the tissue alters the electrical and elasto-mechanical properties of the tissue. These can be evaluated by impedance spectroscopy or ultrasound spectroscopy measurements. A dependence of the extracellular space index (electrical parameter) and the relative backscattering coefficient (acoustical parameter) on the condition of the tissue was found and so it is possible to detect the onset of irreversible damage of the tissue. Both methods are useful measuring methods for monitoring the condition of tissue during ischaemia