Electrical impedance spectroscopy (EIS)-based evaluation of biological tissue phantoms to study multifrequency electrical impedance tomography (Mf-EIT) systems
Type
Article
KAUST Department
Composite and Heterogeneous Material Analysis and Simulation Laboratory (COHMAS)Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2016-03-14Online Publication Date
2016-03-14Print Publication Date
2016-11Permanent link to this record
http://hdl.handle.net/10754/621541Metadata
Show full item recordAbstract
Abstract: Electrical impedance tomography (EIT) phantoms are essential for the calibration, comparison and evaluation of the EIT systems. In EIT, the practical phantoms are typically developed based on inhomogeneities surrounded by a homogeneous background to simulate a suitable conductivity contrast. In multifrequency EIT (Mf-EIT) evaluation, the phantoms must be developed with the materials which have recognizable or distinguishable impedance variations over a wide range of frequencies. In this direction the impedance responses of the saline solution (background) and a number vegetable and fruit tissues (inhomogeneities) are studied with electrical impedance spectroscopy (EIS) and the frequency responses of bioelectrical impedance and conductivity are analyzed. A number of practical phantoms with different tissue inhomogeneities and different inhomogeneity configurations are developed and the multifrequency impedance imaging is studied with the Mf-EIT system to evaluate the phantoms. The conductivity of the vegetable inhomogeneities reconstructed from the EIT imaging is compared with the conductivity values obtained from the EIS studies. Experimental results obtained from multifrequency EIT reconstruction demonstrate that the electrical impedance of all the biological tissues inhomogenity decreases with frequency. The potato tissue phantom produces better impedance image in high frequency ranges compared to the cucumber phantom, because the cucumber impedance at high frequency becomes lesser than that of the potato at the same frequency range. Graphical Abstract: [Figure not available: see fulltext.] © 2016 The Visualization Society of JapanCitation
Bera TK, Nagaraju J, Lubineau G (2016) Electrical impedance spectroscopy (EIS)-based evaluation of biological tissue phantoms to study multifrequency electrical impedance tomography (Mf-EIT) systems. Journal of Visualization 19: 691–713. Available: http://dx.doi.org/10.1007/s12650-016-0351-0.Publisher
Springer NatureJournal
Journal of VisualizationScopus Count
Related items
Showing items related by title, author, creator and subject.
-
Discontinuous Galerkin Time-Domain Modeling of Graphene Nano-Ribbon Incorporating the Spatial Dispersion Effects(IEEE Transactions on Antennas and Propagation, Institute of Electrical and Electronics Engineers (IEEE), 2018-04-13) [Article]It is well known that graphene demonstrates spatial dispersion properties, i.e., its conductivity is nonlocal and a function of spectral wave number (momentum operator) q. In this paper, to account for effects of spatial dispersion on transmission of high speed signals along graphene nano-ribbon (GNR) interconnects, a discontinuous Galerkin time-domain (DGTD) algorithm is proposed. The atomically-thick GNR is modeled using a nonlocal transparent surface impedance boundary condition (SIBC) incorporated into the DGTD scheme. Since the conductivity is a complicated function of q (and one cannot find an analytical Fourier transform pair between q and spatial differential operators), an exact time domain SIBC model cannot be derived. To overcome this problem, the conductivity is approximated by its Taylor series in spectral domain under low-q assumption. This approach permits expressing the time domain SIBC in the form of a second-order partial differential equation (PDE) in current density and electric field intensity. To permit easy incorporation of this PDE with the DGTD algorithm, three auxiliary variables, which degenerate the second-order (temporal and spatial) differential operators to first-order ones, are introduced. Regarding to the temporal dispersion effects, the auxiliary differential equation (ADE) method is utilized to eliminates the expensive temporal convolutions. To demonstrate the applicability of the proposed scheme, numerical results, which involve characterization of spatial dispersion effects on the transfer impedance matrix of GNR interconnects, are presented.
-
Detection of ischemic changes in the vascular endothelial cell layer by using microelectrochemical impedance spectroscopy(Medical Engineering & Physics, Elsevier BV, 2018-10-11) [Article]Endothelial cells have many important roles in the cardiovascular system, such as controlling vasomotor actions and hemostasis. In the event of endothelial cell dysfunction, the risk of cardiovascular disease increases. Therefore, the objective of this study was to investigate the early detection and diagnosis of endothelial cell dysfunction. Injury and restoration in vascular endothelial cells exposed to ischemic stress may affect changes in the electrical impedance. We measured the status of the endothelial cell layer by using microelectrochemical impedance spectroscopy. We used cultured rat primary vascular endothelial cells to measure the electrical impedance under different conditions (control, ischemia, and recovery). Our results revealed that the electrical impedance in vascular endothelial cells under different conditions has quantitatively distinct values. At the optimal frequency, the real parts (Z) of the impedances for the control group, ischemic group, and recovery group were 0.54 kΩ 0.28 kΩ and 0.58 kΩ respectively. The imaginary parts (Z) of the impedances for each group were − 0.19 kΩ − 0.12 kΩ and − 0.18 kΩ respectively. The values for both the recovery group and control group were similar. In this context, electrical impedance measurement could be considered as possible method for direct detection of vascular endothelial cell injury in ischemic conditions. To the best of our knowledge, this study is the first attempt to measure changes in the electrical impedance of vascular endothelial cells during ischemic damage and the recovery processes.
-
Electrical Impedance Characterization for Damage Detection in Carbon Fiber-Reinforced Polymer (CFRP) Laminated Composites(2018-10) [Dissertation]
Advisor: Lubineau, Gilles
Committee members: Younis, Mohammad I.; Salama, Khaled N.; Yudhanto, Arief; Alfano, Marco FrancescoThe use of modern carbon fiber-reinforced polymer (CFRP) composite materials is becoming increasingly widespread recently. However, the failure modes of such composite structures are extremely complex and, unlike metals, they may suffer significant degradation with barely visible surface damage. Since the damage may cause serious decrease in material strength and lead to catastrophic failure, the development of reliable structural health monitoring techniques is indispensable and has a tremendous impact on the life-cycle cost spent for inspection and repair. Such techniques that are based on the change in the electrical properties of materials are promising and viable approach for maintaining the structural integrity. They are low-cost, fast, effective, and have high potential to be applicable on real structures where they can be monitored online and real-time. The topic of this PhD dissertation is mainly focused on a number of key developments and milestones towards monitoring damage in CFRP laminated composites and making electrical-based methods practical on real structures. One of the major components of these methods is the electrode, which is the interface between the external hardware and the monitored structure. We develop a novel method for surface preparation of composite laminates for better electrode quality using pulsed laser irradiation. Further, we provide a new insight on the anisotropic behavior of the contact impedance for the electrodes on CFRP laminated composites. Another major component for achieving reliable monitoring techniques is the in-depth understanding of impedance response of these materials when subjected to an alternating electrical excitation, information that is only partially available in the literature. For more efficient electrical signal-based inspections, we investigate the electrical impedance spectroscopy response at various frequencies of laminates chosen to be representative of classical layups employed in composite structures. Finally, we use different electrodes configurations on CFRP plates applied to one side mimicking the case of real structures that is undergoing a quasi-static indentation representative of the impact load. We investigate the coupling between the electrical measurements and the type of mechanical degradation using an in-house built electro-mechanical system that measures the change in impedance and phase angle in-situ and real-time.
