An instrumental electrode model for solving EIT forward problems

An instrumental electrode model (IEM) capable of describing the performance of electrical impedance tomography (EIT) systems in the MHz frequency range has been proposed. Compared with the commonly used Complete Electrode Model (CEM), which assumes ideal front-end interfaces, the proposed model considers the effects of non-ideal components in the front-end circuits. This introduces an extra boundary condition in the forward model and offers a more accurate modelling for EIT systems. We have demonstrated its performance using simple geometry structures and compared the results with the CEM and full Maxwell methods. The IEM can provide a significantly more accurate approximation than the CEM in the MHz frequency range, where the full Maxwell methods are favoured over the quasi-static approximation. The improved electrode model will facilitate the future characterization and front-end design of real-world EIT systems.

[1]  Gary J Saulnier,et al.  A high-precision voltage source for EIT. , 2006, Physiological measurement.

[2]  Andy Adler,et al.  Electrode models under shape deformation in Electrical Impedance Tomography , 2010 .

[3]  J.P. Kaipio,et al.  Three-dimensional electrical impedance tomography based on the complete electrode model , 1999, IEEE Transactions on Biomedical Engineering.

[4]  David Isaacson,et al.  Electrical Impedance Tomography , 1999, SIAM Rev..

[5]  Peyman Mirtaheri,et al.  Electrode polarization impedance in weak NaCl aqueous solutions , 2005, IEEE Transactions on Biomedical Engineering.

[6]  Eung Je Woo,et al.  Calibration methods for a multi-channel multi-frequency EIT system , 2007, Physiological measurement.

[7]  D. C. Barber,et al.  Three-dimensional electrical impedance tomography , 1996, Nature.

[8]  Eric L. Miller,et al.  Finite Element Modeling of Electromagnetic Scattering for Microwave Breast Cancer Detection , 2010 .

[9]  Eung Je Woo,et al.  Frequency-difference electrical impedance tomography (fdEIT): algorithm development and feasibility study , 2008, Physiological measurement.

[10]  Ryan Halter,et al.  Design and implementation of a high frequency electrical impedance tomography system. , 2004, Physiological measurement.

[11]  Manuchehr Soleimani,et al.  Improving the forward solver for the complete electrode model in EIT using algebraic multigrid , 2005, IEEE Transactions on Medical Imaging.

[12]  Keith D. Paulsen,et al.  Nodal-based finite-element modeling of Maxwell's equations , 1992 .

[13]  Alan Murray,et al.  Thermography and colour duplex ultrasound assessments of arterio-venous fistula function in renal patients , 2006, Physiological measurement.

[14]  F J Lidgey,et al.  A high output impedance current source. , 1994, Physiological measurement.

[15]  Xin-Qing Sheng,et al.  Essentials of Computational Electromagnetics: Sheng/Essentials of Computational Electromagnetics , 2012 .

[16]  Keith D. Paulsen,et al.  A Broadband High-Frequency Electrical Impedance Tomography System for Breast Imaging , 2008, IEEE Transactions on Biomedical Engineering.

[17]  William R B Lionheart,et al.  A Matlab toolkit for three-dimensional electrical impedance tomography: a contribution to the Electrical Impedance and Diffuse Optical Reconstruction Software project , 2002 .

[18]  Hervé Gagnon,et al.  A method for modelling and optimizing an electrical impedance tomography system , 2006, Physiological measurement.

[19]  Eung Je Woo,et al.  Weighted frequency-difference EIT measurement of hemisphere phantom , 2010 .

[20]  K. D. Paulsen,et al.  Accurate solutions of Maxwell's equations around PEC corners and highly curved surfaces using nodal finite elements , 1997 .

[21]  Xin-Qing Sheng,et al.  Essentials of Computational Electromagnetics , 2012 .

[22]  Eung Je Woo,et al.  A fully parallel multi-frequency EIT system with flexible electrode configuration: KHU Mark2 , 2011, Physiological measurement.

[23]  Sverre Grimnes,et al.  Bioimpedance and Bioelectricity Basics , 2000 .

[24]  R Bayford,et al.  Design and calibration of a compact multi-frequency EIT system for acute stroke imaging. , 2006, Physiological measurement.

[25]  E. Somersalo,et al.  Existence and uniqueness for electrode models for electric current computed tomography , 1992 .

[26]  Anjan Rakshit,et al.  Development and study of an automatic AC bridge for impedance measurement , 2001, IEEE Trans. Instrum. Meas..

[27]  William R B Lionheart,et al.  Uses and abuses of EIDORS: an extensible software base for EIT , 2006, Physiological measurement.

[28]  Alexander S Ross,et al.  Current source design for electrical impedance tomography. , 2003, Physiological measurement.

[29]  Eung Je Woo,et al.  Factorization Method and Its Physical Justification in Frequency-Difference Electrical Impedance Tomography , 2010, IEEE Transactions on Medical Imaging.

[30]  Sverre Grimnes,et al.  History of Bioimpedance and Bioelectricity , 2008 .

[31]  Yuqing Wan,et al.  Statistical Estimation of EIT Electrode Contact Impedance Using a Magic Toeplitz Matrix , 2011, IEEE Transactions on Biomedical Engineering.

[32]  D. Isaacson,et al.  Electrode models for electric current computed tomography , 1989, IEEE Transactions on Biomedical Engineering.

[33]  Eung Je Woo,et al.  Multi-frequency EIT system with radially symmetric architecture: KHU Mark1 , 2007, Physiological measurement.

[34]  H. Schwan.  Electrical properties of tissue and cell suspensions. , 1957, Advances in biological and medical physics.

[35]  R. van Mastrigt,et al.  Development of a CFD urethral model to study flow-generated vortices under different conditions of prostatic obstruction , 2007, Physiological measurement.

[36]  Keith D. Paulsen,et al.  Finite element implementation of Maxwell's equations for image reconstruction in electrical impedance tomography , 2006, IEEE Transactions on Medical Imaging.

[37]  J P Kaipio,et al.  Assessment of errors in static electrical impedance tomography with adjacent and trigonometric current patterns. , 1997, Physiological measurement.

[38]  Yue Xiu-li,et al.  Multifunctional magnetic nanoparticles for magnetic resonance image-guided photothermal therapy for cancer , 2014 .

[39]  Wei Wang,et al.  A high-speed bioelectrical impedance spectroscopy system based on the digital auto-balancing bridge method , 2013 .

[40]  Hervé Gagnon,et al.  Accounting for hardware imperfections in EIT image reconstruction algorithms , 2007, Physiological measurement.

[41]  Eung Je Woo,et al.  Frequency-difference EIT (fdEIT) using weighted difference and equivalent homogeneous admittivity: validation by simulation and tank experiment , 2009, Physiological measurement.

[42]  K. Paulsen,et al.  Continuous potential Maxwell solutions on nodal-based finite elements , 1992 .

[43]  Andy Adler,et al.  The impact of electrode area, contact impedance and boundary shape on EIT images , 2011, Physiological measurement.

[44]  B. Brown,et al.  Applied potential tomography. , 1989, Journal of the British Interplanetary Society.

[45]  David S. Holder,et al.  Electrical Impedance Tomography : Methods, History and Applications , 2004 .

[46]  Bong Seok Kim,et al.  The Complete Electrode Model For Imaging and Electrode Contact Compensation in Electrical Impedance Tomography , 2007, 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[47]  Eugene Demidenko,et al.  An analytic solution to the homogeneous EIT problem on the 2D disk and its application to estimation of electrode contact impedances , 2011, Physiological measurement.

[48]  William R B Lionheart.  EIT reconstruction algorithms: pitfalls, challenges and recent developments. , 2004, Physiological measurement.

[49]  C. N. McLeod,et al.  Current source calibration simplifies high-accuracy current source measurement , 1994 .

[50]  Stuchly,et al.  Dielectric properties of breast carcinoma and the surrounding tissues , 1988, IEEE Transactions on Biomedical Engineering.