Investigation of physiological swelling on conductivity distribution in lower leg subcutaneous tissue by electrical impedance tomography

Abstract

There is a strong need for a non-invasive measurement technique that is capable of accurately identifying the physiological condition change or heterogeneity of subcutaneous adipose tissue (SAT) by localizing the abnormalities within the compartment. This paper aims to investigate the feasibility of Electrical Impedance Tomography (EIT) to assess the interstitial fluid in subcutaneous adipose tissue as an enhancement method of bioelectrical impedance spectroscopy (BIS). Here, we demonstrate the preliminary result of EIT with a wearable 16 electrodes sensor. The image-based reference EIT with fat weighted threshold method is proposed. In order to evaluate the performance of our novel method, a physiological swelling experiment is conducted, and Multi-Frequency Bioelectrical Impedance Analysis (MFBIA) is also applied as a comparison with EIT results. The experimental results showed that the proposed method was able to distinguish the physiological swelling condition and effectively to remove the unexpected background noise. Furthermore, the conductivity variation in the subcutaneous layer had a good correlation with extracellular water volume change from MFBIA data; the correlation coefficient R2 = 0.927. It is concluded that the proposed method provides a significant prospect for SAT assessment.

In-vivo viscoelastic properties estimation in subcutaneous adipose tissue by integration of poroviscoelastic-mass transport model (pve-MTM) into wearable electrical impedance tomography (w-EIT)

“…All of the subjects were in the sitting position between thigh and calf forming an angle of 90 degrees and requested not to do a heavy activity 3 h before measurement. This sitting position was arranged to avoid the change of water volume and reduce the flow effect to the upper area of human calf by the influence of the gravity effect (Chester et al 2002, Ogawa et al 2020. The -P t ( ) was applied to the calf part on the CDEF cross-section to induce the fluid flow q and ion movement c (black arrow line in figure 4) from DE cross-section to AB cross-section (z (+) direction).…”

“…Figure 3 shows the schematic of wearable electrical impedance tomography (w-EIT), which consists of electrodes e , 1 e , 2 e , ℓ K, e L (L=16) embedded inside the black elastic polyester cloth to adapt to the boundary shape ¶W of human calf. The wearable sensor in w-EIT has the ability to adapt the boundary shape of the human body as the human body forms an irregular shape (Darma et al 2020, Ogawa et al 2020. The electrodes are appropriately attached to the skin of the human body so that the injected current is able to pass through the skin.…”

Evaluation of the effectiveness of electrical muscle stimulation on human calf muscles via frequency difference electrical impedance tomography

“…We have already applied a unique EIT called frequency difference electrical impedance tomography ( fd-EIT) to detect flexible boundary shapes of bio-related objects with wearable sensors (Darma et al 2020). fd-EIT was also applied to heterogeneous imaging in subcutaneous adipose tissue due to physiological change by localizing abnormalities in the compartment (Ogawa et al 2020). Therefore, in this study, we have proposed fd-EIT for imaging response muscle areas of human muscles under EMS in situ, especially focusing on calf muscles.…”

The Trade-off in Machine Learning Application for Electrical Impedance Tomography

“…It is also a fundamental way to evaluate the object of interest in the frequency spectrum of reconstructed images [6,7] . Additionally, the conductivity of change of the object of interest occurs in the time domain monitoring or imaging [8] . Moreover, integrating with other modalities with different sensor configurations could be possible such as with electrical capacitance tomography (ECT) [9,10] , mutual inductance tomography (MIT) [11] , and Ultrasonography [12] .…”