Electrical Impedance Spectroscopic Studies on Broiler Chicken Tissue Suitable for the Development of Practical Phantoms in Multifrequency EIT

Abstract

Phantoms are essential for assessing the system performance in Electrical Impedance Tomography (EIT). Saline phantoms with insulator inhomogeneity fail to mimic the physiological structure of real body tissue in several aspects. Saline or any other salt solutions are purely resistive and hence studying multifrequency EIT systems cannot be assessed with saline phantoms because the response of the purely resistive materials do not change over frequency. Animal tissues show a variable response over a wide band of signal frequency due to their complex physiological and physiochemical structures and hence they can suitably be used as bathing medium and inhomogeneity in the phantoms of multifrequency EIT system. An efficient assessment of a multifrequency EIT system with real tissue phantom needs a prior knowledge of the impedance profile of the bathing medium as well as the inhomogeneity. In this direction Electrical Impedance Spectroscopy (EIS) of broiler chicken muscle tissue paste and broiler chicken fat tissue is conducted from 10 Hz to 2 MHz using an impedance analyzer and their impedance profiles are thoroughly studied. Results show that the broiler chicken muscle tissue paste is less resistive than the fat tissue and hence it can be successfully used as the bathing medium of the phantoms for resistivity imaging in multifrequency EIT. Fat tissue is found more resistive than the muscle tissue which makes it more suitable for the inhomogeneity in phantoms of resistivity imaging study. <p><a href="http://dx.doi.org/10.5617/jeb.174" target="_blank">doi:10.5617/jeb.174 </a><br />J Electr Bioimp, vol. 2, pp. 48-63, 2011</p&gt

A battery-based constant current source (Bb-CCS) for biomedical applications

“…The frequency response of the electrical impedance of the biological tissues varies with physiological and physiochemical health status. Frequency response of the bioelectrical impedance varies from subject to subject [10][11][12][13][14][15][16][17] and it may also vary from one tissue part to another tissue part within a particular subject. Moreover, the bioelectrical impedance of biological tissues varies with the measurement directions for the same tissue called anisotropic tissues [9].…”

“…In two electrode method the current injection and voltage measurements are conducted through the same electrodes pairs (Fig. 1a) and hence, it is known as two-electrode technique [16]. On the contrary, the four-probe method [16] injects the frequency dependent current signal (I(ω)) through two-electrodes (called current electrodes or driving electrodes) as shown by the red electrodes in Fig.…”

“…1a) and hence, it is known as two-electrode technique [16]. On the contrary, the four-probe method [16] injects the frequency dependent current signal (I(ω)) through two-electrodes (called current electrodes or driving electrodes) as shown by the red electrodes in Fig. 1b and the frequency dependent electric potential (V(ω)) developed, is measured [16] across other two electrodes (called voltage electrodes or sensing electrodes) blue electrodes (Fig.…”

Measurement of bio-impedance on an isolated rat sciatic nerve obtained with specific current stimulating pulses

“…Some of these analysing techniques provide Z values of the tissue sample as a lumped estimation at a suitable frequency range and the information on several complex bioelectrical phenomena occurring in cells and tissues under an alternating (AC) electric current signal. 1,2 In this regard, a measurement of the complex Z in biological systems is one of the developing technologies for monitoring and determining the pathological and physiological status of biological tissues. 3 Namely, with AC electrical stimulation, biological tissues produce a complex Z that depends on the tissue composition, structures, health status, and applied stimulus frequency.…”

“…In the four-probe, Z measurement set-up, the current is fed through two feeding electrodes 1,4 (considered as drive terminals) within the line of four equidistantly placed electrodes, while the voltage drop is measured between two measurement electrodes 2,3 (considered as measurement terminals). The voltage is measured with an instrument that has a very high input Z, so that almost no current flows through the measurement electrodes, i.e., their cables and contact resistance play almost no role in the measurement.…”