Determination of absolute lung resistivity as a function of air volume using electrical impedance tomography

Comparing the measurements from electrical impedance tomography (EIT) with that from a 3D finite difference model of the thorax, absolute lung resistivity may be determined by using EIT dynamic imaging technique. Using this method, we derived the lung resistivities and the changes as a function of air volume (inspired 0.5 liter, 1.0 liter and 1.5 liter from FRC) for adult subjects. The results are compared with the lung resistivity measured by an invasive technique. The preliminary results show the feasibility of using this method to trace the physiological changes of the lung. Further study is required including electrode position, chest expansion and size, and changes of resistivities of other organs in model.