Towards Estimating Arterial Diameter Using Bioimpedance Spectroscopy: A Computational Simulation and Tissue Phantom Analysis

Abstract

This paper improves the accuracy of quantification in the arterial diameter‐dependent impedance variance by altering the electrode configuration. The finite element analysis was imple-mented with a 3D human wrist fragment using ANSYS Electronics Desktop, containing fat, muscle, and a blood‐filled radial artery. Then, the skin layer and bones were stepwise added, helping to understand the dielectric response of multi‐tissues and blood flow from 1 kHz to 1 MHz, the current distribution throughout the wrist, and the optimisation of electrode configurations for arterial pulse sensing. Moreover, a low‐cost wrist phantom was fabricated, containing two components: the sur-rounding tissue simulant (20 wt % gelatine power and 0.017 M sodium chloride (NaCl) solution) and the blood simulant (0.08 M NaCl solution). The blood‐filled artery was constricted using a desktop injection pump, and the impedance change was measured by the Multi‐frequency Impedance Analyser (MFIA). The simulation revealed the promising capabilities of band electrodes to generate a more uniform current distribution than the traditional spot electrodes. Both simulation and phantom experimental results indicated that a longer spacing between current‐carrying (CC) electrodes with shorter spacing between pick‐up (PU) electrodes in the middle could sense a more uniform electric field, engendering a more accurate arterial diameter estimation. This work provided an improved electrode configuration for more accurate arterial diameter estimation from the numerical simulation and tissue phantom perspectives.