ELECTRICAL IMPEDANCE TOMOGRAPHY

Incorporating A-Priori Information in Electrical Impedance Image Reconstruction

In order to measure in vivo resistivity of tissues in the thorax, the possibility of combining anatomical data extracted from high-resolution images with multiple-electrode impedance measurements and a-priori data on the instrumentation noise is assessed. A statistically constrained minimum-mean-square (MiMSEE) error estimator is used to estimate tissue resistivities. MiMSEE minimizes the errors due to linearization and instrumentation noise. Statistical constraint information is based on the a-priori knowledge of physiologically allowed range of tissue resistivities, statistical properties of the linearization error and the instrumentation noise.

References:
Eyuboglu et al, 1994, "Estimation of tissue resistivities from multiple-electrode impedance measurements," Physics in Medicine and Biology, Vol.39, pp.1-17. article.pdf

U.Baysal and B.M. Eyuboglu, "Tissue resistivitivity estimation in the presence of positional and geometrical uncertainties," Physics in
Medicine and Biology, Vol.45, No.8, pp.2373-2388, 2000. article.pdf

U.Baysal and B.M. Eyuboglu, "Use of a priori Information in Estimating Tissue Resistivities - application to measured data," Physics in
Medicine and Biology, Vol.44, No.7, pp.1677-1689, 1999.

U.Baysal and B.M. Eyuboglu, "Use of a priori Information in Estimating Tissue Resistivities - a simulation study," Physics in Medicine and
Biology, Vol.43, No.12, pp.3589-3606, 1998.
 
 

Electrical Impedance Imaging of Pulmonary Ventilation

Electrical impedance tomography (EIT) ventilation images from a group of 12 patients (with emphysema) and a group of 15 normal subjects were acquired using a Sheffield mark 1 EIT system, at the levels of second, fourth and sixth intercostal spaces. Ventilation-related conductivity changes at total lung capacity (TLC) relative to residual volume were measured quantitatively in EIT images. These quantitative values demonstrate marked differences compared to those values obtained from the EIT images of 15 normal subjects.

Reference: Eyuboglu et al, 1995, "Application of electrical impedance tomography in diagnosis of emphysema- a clinical study," Physiological Measurement, V.16, pp.A191-211. article.pdf

Optimum Injected and Induced Current Patterns in Electrical Impedance Tomography

References:

Koksal and Eyuboglu, 1995, "Determination of optimum injected current patterns in electrical impedance tomography," Physiological Measurement, V.16, pp.A99-109. article.pdf

B.M. Eyuboglu, A. Koksal and M. Demirbilek, "Distinguishability analysis of an induced current EIT system using discrete coils," Physics in
Medicine and Biology, Vol.45, No.7, pp.1997-2009, 2000. article.pdf

An Interleaved Drive Electrical Impedance Tomography Image Reconstruction Algorithm

Reference: Eyuboglu, 1996, In Print, Physiological Measurement. article.pdf