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A technology for high-resolution efficient numerical modelling of bioimpedance measurements is considered that includes 3D image segmentation, adaptive unstructured tetrahedral mesh generation, finite-element discretization, and analysis of simulation data. The first-order convergence of the proposed numerical methods on a series of unmatched meshes and roughly second-order convergence on a series of nested meshes are shown. The current, potential, and sensitivity field distributions are computed for conventional schemes of bioimpedance measurements using segmented geometrical torso model of the Visible Human Project (VHP) man. Use of the adaptive tetrahedral meshes reduces significantly the number of mesh elements and, hence, the associated computational cost compared to rectangular meshes while keeping the model accuracy.

A study of the α- and β-dispersion of skin bioimpedance dependence on temperature and micro-hemodynamics is presented. The vascular tone changes during the cold test are verified by the wavelet-analysis of skin temperature signals obtained simultaneously with impedance measurements. Thirty three normal healthy subjects of 28  ±  7 years old were entered into the study. The tetra-polar electrode system was used to record the resistance and reactance; measurements were carried out at 67 frequencies, in a frequency range from 2 Hz to 50 kHz. It has been found that the impedance decreases with vasodilation and increases with vasoconstriction. The high values of correlation among thermal oscillation amplitudes and Nyquist diagram parameters prove the impedance dependence on blood flow in three frequency bands corresponding to the myogenic, neurogenic and endothelial vascular tone regulation mechanisms. Using an equivalent RC circuit, we obtained the changes in the Nyquist diagram matching the experimental data. The proposed descriptive α-dispersion model can be used to study mechanisms responsible for intercellular interaction.

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