Bioimpedance dispersion width as a parameter to monitor living tissues

Abstract

In the case of living tissues, the spectral width of the electrical bioimpedance dispersions (closely related with the alpha parameter in the Cole equation) evolves during the ischemic periods. This parameter is often ignored in favor of other bioimpedance parameters such as the central frequency or the resistivity at low frequencies. The object of this paper is to analyze the significance of this parameter through computer simulations (in the alpha and beta dispersion regions) and to demonstrate its practical importance through experimental studies performed in rat kidneys during cold preservation. The simulations indicate that the dispersion width could be determined by the morphology of the extra-cellular spaces. The experimental studies show that it is a unique parameter able to detect certain conditions such as a warm ischemia period prior to cold preservation or the effect of a drug (Swinholide A) able to disrupt the cytoskeleton. The main conclusion is that, thanks to the alpha parameter in the Cole equation, the bioimpedance is not only useful to monitor the intra/extra-cellular volume imbalances or the inter-cellular junctions resistance but also to detect tissue structural alterations.

In vivo electrical impedance measurements during and after electroporation of rat liver

“…However, it is difficult to fit such explanation to experimental results such as those presented here in which α decreases significantly and an increase of cell size heterogeneity is not observed. On the other hand, current results and observations seem to reinforce the idea that α is strongly related to the morphology of the extra-cellular spaces [37].…”

The Feasibility of a Smart Surgical Probe for Verification of IRE Treatments Using Electrical Impedance Spectroscopy

“…The physical meaning of the CPE is a matter of debate. However α could be regarded as a measure of a distribution of the resistance-capacitance combination and is related to the morphology of the extracellular space [63]. After impedance measurement, the Gamry Echem Analyst software is used to fit the model to the acquired data and get the values for the above parameters.…”

Cole–Cole, linear and multivariate modeling of capacitance data for on-line monitoring of biomass

“…It seems likely that the value of a is often due to a variety of effects, some of which are more or less important in different systems. The following are some of the suggested origins of this parameter's value: distribution of cell shapes and sizes [28], morphology of extra-cellular spaces [29], mobility of membranous proteins [30,31] and the fractal nature of dielectric relaxation [32]. Typical values of a for biological cells are in the order of 0.1 to 0.2 [13].…”