Correlation of electrical impedance with mechanical properties in models of tissue mimicking phantoms

Pathological changes in soft-tissues are primarily correlated with changes in their mechanical and electrical properties and are used to differentiate diseases from normals. Although there are evidences that establish the association of electrical and mechanical properties in biological aspects, their interrelationships are not well established. In this work, an attempt has been made to correlate electrical impedance of soft tissue-mimicking phantoms with those of its mechanical properties. The electrical property of the polyacrylamide gel phantoms prepared as per the standard protocol was studied using a precision impedance analyzer. Tensile tests were conducted using an universal testing machine and the derived mechanical properties such as breaking stress, breaking strain, initial modulus and Young's modulus were correlated with impedance values. It was observed that for a given concentration of a gel phantom the percentage variation in impedance correlate well with the percentage variation in the Young's modulus. The magnitude of variation in Young's modulus found to be more than that of the impedance. Similar correlations were observed for other mechanical properties. It appears that this study seems to be useful as the research on tissue mimicking phantom gels play important role in mechanical studies and in ultrasonic bioeffects. In this paper the objectives of the study, methodology and the significance of results are discussed in detail.