Current constrained voltage scaled reconstruction (CCVSR) algorithm for MR-EIT and its performance with different probing current patterns

Download

index.pdf

Date

2003-03-07

Author

Birgul, O
Eyüboğlu, Behçet Murat
Ider, YZ

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

166
views

0
downloads

Conventional injected-current electrical impedance tomography (EIT) and magnetic resonance imaging (MRI) techniques can be combined to reconstruct high resolution true conductivity images. The magnetic flux density distribution generated by the internal current density distribution is extracted from MR phase images. This information is used to form a fine detailed conductivity image using an Ohm's law based update equation. The reconstructed conductivity image is assumed to differ from the true image by a scale factor. EIT surface potential measurements are then used to scale the reconstructed image in order to find the true conductivity values. This process is iterated until a stopping criterion is met. Several simulations are carried out for opposite and cosine current injection patterns to select the best current injection pattern for a 2D thorax model. The contrast resolution and accuracy of the proposed algorithm are also studied. In all simulation studies, realistic noise models for voltage and magnetic flux density measurements are used. It is shown that, in contrast to the conventional EIT techniques, the proposed method has the capability of reconstructing conductivity images with uniform and high spatial resolution. The spatial resolution is limited by the larger element size of the finite element mesh and twice the magnetic resonance image pixel size.

Subject Keywords

Radiological and Ultrasound Technology, Radiology Nuclear Medicine and imaging

URI

https://hdl.handle.net/11511/47338

Journal

PHYSICS IN MEDICINE AND BIOLOGY

DOI

https://doi.org/10.1088/0031-9155/48/5/307

Collections

Department of Electrical and Electronics Engineering, Article

Suggestions

OpenMETU
Core

Experimental results for 2D magnetic resonance electrical impedance tomography (MR-EIT) using magnetic flux density in one direction Birgul, O; Eyüboğlu, Behçet Murat; Ider, YZ (IOP Publishing, 2003-11-07) Magnetic resonance electrical impedance tomography (MR-EIT) is an emerging imaging technique that reconstructs conductivity images using magnetic flux density measurements acquired employing MRI together with conventional EIT measurements. In this study, experimental MR-EIT images from phantoms with conducting and insulator objects are presented. The technique is implemented using the 0.15 T Middle East Technical University MRI system. The dc current method used in magnetic resonance current density imaging...
Anisotropic conductivity imaging with MREIT using equipotential projection algorithm DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (IOP Publishing, 2007-12-21) Magnetic resonance electrical impedance tomography (MREIT) combines magnetic flux or current density measurements obtained by magnetic resonance imaging (MRI) and surface potential measurements to reconstruct images of true conductivity with high spatial resolution. Most of the biological tissues have anisotropic conductivity; therefore, anisotropy should be taken into account in conductivity image reconstruction. Almost all of the MREIT reconstruction algorithms proposed to date assume isotropic conductivi...
Forward problem solution of electromagnetic source imaging using a new BEM formulation with high-order elements Gençer, Nevzat Güneri (IOP Publishing, 1999-09-01) Representations of the active cell populations on the cortical surface via electric and magnetic measurements are known as electromagnetic source images (EMSIs) of the human brain. Numerical solution of the potential and magnetic fields for a given electrical source distribution in the human brain is an essential part of electromagnetic source imaging. In this study, the performance of the boundary element method (BEM) is explored with different surface element types. A new BEM formulation is derived that m...
ESTIMATION OF TISSUE RESISTIVITIES FROM MULTIPLE-ELECTRODE IMPEDANCE MEASUREMENTS Eyüboğlu, Behçet Murat; WOLF, PD (IOP Publishing, 1994-01-01) 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, a priori knowledge of the range of tissue resistivities, and a priori data on the instrumentation noise is assessed in this study. A statistically constrained minimum-mean-square error estimator (MIMSEE) that minimizes the effects of linearization errors and instrumentation noise is developed and compared to the c...
Lorentz force electrical impedance tomography using magnetic field measurements ZENGİN, Reyhan; Gençer, Nevzat Güneri (IOP Publishing, 2016-08-21) In this study, magnetic field measurement technique is investigated to image the electrical conductivity properties of biological tissues using Lorentz forces. This technique is based on electrical current induction using ultrasound together with an applied static magnetic field. The magnetic field intensity generated due to induced currents is measured using two coil configurations, namely, a rectangular loop coil and a novel xy coil pair. A time-varying voltage is picked-up and recorded while the acoustic...

Citation Formats

O. Birgul, B. M. Eyüboğlu, and Y. Ider, “Current constrained voltage scaled reconstruction (CCVSR) algorithm for MR-EIT and its performance with different probing current patterns,” PHYSICS IN MEDICINE AND BIOLOGY, pp. 653–671, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47338.