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 implemented 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 surrounding 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.

A Pilot Study Examining the Dielectric Response of Human Forearm Tissues

“…In this study, we initially conducted an FEM simulation using ANSYS HFSS to gain a deeper understanding of the E-field distribution within the entire forearm model. As illustrated in Figure 3, the simulation results confirmed a higher E-field concentration around the current-carrying electrodes, consistent with prior research findings [13,28]. Notably, it was found that resistive effects were predominant across the investigated frequency range.…”

“…Bioimpedance measurement (BIM) provides information about the physical and electrochemical processes in the tissue region and hence can be used for monitoring physiological properties and variations [4]. BIA has been widely utilized for body composition [5][6][7][8] and developed to track pulse wave propagation [9][10][11][12] and estimate the arterial diameter change [13][14][15][16]. The fundamental principle of BIM is that a small amount of alternating current is applied through the outer pair of electrodes (current-carrying electrodes), and the voltage in response is measured through the same or a different inner pair of electrodes (pick-up electrodes).…”

“…The application of MF-BIA for hemodynamic monitoring has been investigated by several previous studies using computational simulation [28], tissue phantom experiments [13,29] and human subject measurement [15]. The objective of this study is to present a mathematical modelling approach where the dielectric properties of forearm tissues will be identified through MF-BIA.…”

Bioimpedance spectroscopy measurement method based on multisine excitation and integer-period undersampling

“…Bioimpedance spectroscopy (BIS) concerns the conductive and dielectric properties of organisms when a weak alternating current below the excitation threshold passes through them [1]. Due to its advantages of non-invasiveness, low cost and simple operation, BIS has been widely used in clinical research, for example in body composition analysis [2], cancer detection and evaluation [3,4], biological cell detection [5], biological tissue detection and evaluation [5,6], and human organ status monitoring and analysis [7].…”

A Pilot Study Examining the Dielectric Response of Human Forearm Tissues

“…Bioimpedance measurement (BIM) provides information about the physical and electrochemical processes in the tissue region and hence can be used for monitoring physiological properties and variations [4]. BIA has been widely utilised for body composition [5][6][7][8] and developed to track pulse wave propagation [9][10][11][12] and estimate the arterial diameter change [13][14][15][16]. The fundamental principle of BIM is that a small amount of alternating current is applied through the outer pair of electrodes (current-carrying electrodes), and the voltage in response is measured through the same or a different inner pair of electrodes (pick-up electrodes).…”