Electrical impedance tomography: Induced-current imaging achieved with a multiple coil system

Gençer, Nevzat Güneri
Williamson, SJ
An experimental study of induced-current electrical impedance tomography verifies that image quality Is enhanced by employing six rather than three induction coils by increasing the number of independent measurements. However, with an increasing number of coils, the inverse problem becomes more sensitive to measurement noise, Using 16 electrodes to measure surface voltages, it Is possible to collect 6 x 15 = 90 independent measurements. For comparison purposes, images of two dimensional conductivity perturbations are reconstructed by using the data for three and six coils with the truncated pseudoinverse algorithm, By searching for the optimal truncation index that minimizes the noise error plus the resolution error, the signal-to-noise ratio of the data acquisition system was established as 58 db, Images obtained with this six-coil system reveal the sizes and locations of the conductivity perturbations, This system also provides images within the central region of the object space, a capability not achieved in previous experimental studies using only three circular coils, Nevertheless, the three-coil system can identify the conductivity perturbations near the periphery, However, it displays shifts in the locations and spread in the sizes of perturbations near the center of the object.


Electrical Impedance Tomography Induced Current
Gençer, Nevzat Güneri (2006-01-01)
The ultimate goal of induced‐current electrical impedance tomography (ICEIT) is to image the electrical impedance distribution within the human body. In ICEIT, time‐varying magnetic fields are applied to induce currents in the body and surface voltage measurements are used to reconstruct impedance distribution. Time‐varying fields are usually generated by sinusoidal current‐carrying wires encircling the conducting body. Given the conductivity distribution, calculating the surface voltages due a given coil c...
Gençer, Nevzat Güneri; Kuzuoğlu, Mustafa (1994-06-01)
The mathematical basis of a new imaging modality, Induced Current Electrical Impedance Tomography (EIT), is investigated. The ultimate aim of this technique is the reconstruction of conductivity distribution of the human body, from voltage measurements made between electrodes placed on the surface, when currents are induced inside the body by applied time varying magnetic fields. In this study the two-dimensional problem is analyzed. A specific 9-coil system for generating nine different exciting magnetic f...
Equipotential projection based magnetic resonance electrical impedance tomography (mr-eit) for high resolution conductivity imaging
Özdemir, Mahir Sinan; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2003)
In this study, a direct reconstruction algorithm for Magnetic Resonance Electrical Impedance Tomography (MR-EIT) is proposed and experimentally implemented for high resolution true conductivity imaging. In MR-EIT, elec trical impedance tomography (EIT) and magnetic resonance imaging (MRI) are combined together. Current density measurements are obtained making use of Magnetic Resonance Current Density Imaging (MR-CDI) techniques and peripheral potential measurements are determined using conventional EIT tech...
Eyüboğlu, Behçet Murat; BARBER, DC (1989-03-01)
Electrical impedance tomography (EIT) produces cross-sectional images of the electrical resistivity distribution within the body, made from voltage or current measurements through electrodes attached around the body. The authors describe a gated EIT system to image the cardiogenic electrical resistivity variations and the results of in vivo studies on human subjects. It is shown that the sensitivity of EIT to tissue resistivity variations due to blood perfusion is good enough to image blood flow to the lung...
Induced current magnetic resonance electrical impedance tomography (ICMREIT) with low frequency switching of gradient fields
Eroğlu, Hasan Hüseyin; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2017)
In this thesis, it is aimed to investigate induced current magnetic resonance electrical impedance tomography (ICMREIT) starting from modeling and analysis to experimental validation. Forward and inverse problems of ICMREIT are formulated. A magnetic resonance imaging (MRI) pulse sequence is proposed for the realization of ICMREIT using the slice selection (z) gradient coil of MRI scanners. Considering the proposed MRI pulse sequence, relationship between the low frequency (LF) MR phase and the secondary ma...
Citation Formats
N. G. Gençer and S. Williamson, “Electrical impedance tomography: Induced-current imaging achieved with a multiple coil system,” IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, pp. 139–149, 1996, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46366.