Equipotential projection based magnetic resonance electrical impedance tomography (mr-eit) for high resolution conductivity imaging

Download

143132.pdf

Date

2003

Author

Özdemir, Mahir Sinan

Metadata

Show full item record

Item Usage Stats

278
views

0
downloads

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 techniques. 0.15 Tesla METU MRI system is used for MR-EIT technique and opposite DC current injection method is adopted for MR-CDI technique. The fast, non-iterative image reconstruction algorithm used in reconstructing inte rior conductivity distribution is based on the fact that equip otential lines are perperdicular to current vectors. The suggested method is tested on both sim ulated and experimental data for conductor and insulator objects and results are presented. In the simulation results, error in the reconstructed conductiv ity is found to be between 12.4%-13.9% for background and 22.4%-32.9% for the object. The spatial resolution is space independent and is limited by twice, the MRI pixel size. It is shown that the proposed technique can be used to re construct conductivity images with high resolution and accurate conductivity.

Subject Keywords

Electrical impedance tomography, Electrical impedance tomography, Magnetic resonance imaging, Current density imaging

URI

https://hdl.handle.net/11511/13637

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Equipotential projection based MREIT reconstruction without potential measurements Eyüboğlu, Behçet Murat (2007-09-02) Magnetic resonance electrical impedance tomography (MREIT) is used to produce high resolution images of true conductivitv distribution. Images are reconstructed by utilising measurements of magnetic flux density distribution and surface potentials. Surface potential measurements are needed to reconstruct true conductivity values. In this study, a novel MREIT reconstruction algorithm is developed to generate conductivity images without utilizing the surface potential measurements. The proposed algorithm and ...
Magnetic Resonance - Electrical Impedance Tomography (MR-EIT) Research at METU Eyüboğlu, Behçet Murat (2006-09-01) Following development of magnetic resonance current density imaging (MRCDI), magnetic resonance - electrical impedance tomography (MR-EIT) has emerged as a promising approach to produce high resolution conductivity images. Electric current applied to a conductor results in a potential field and a magnetic flux density distribution. Using a magnetic resonance imaging (MRI) system, the magnetic flux density distribution can be reconstructed as in MRCDI. The flux density is related to the current density distr...
Regional Image Reconstruction with Optimum Currents for MREIT - Evaluation on Shepp-Logan Conductivity Phantom Eyüboğlu, Behçet Murat; Altunel, Haluk (2008-11-27) In this study, an image reconstruction algorithm for magnetic resonance electrical impedance tomography (MREIT) is proposed to achieve maximum benefit of optimum current injection patterns. By doing so, considerable reduction in probing current amplitude could be possible. In the proposed algorithm, field of view (FOV) is divided into a number of segments. Image of each segment is reconstructed separately, based on measurements obtained using the best (optimum) current patterns, which maximize distinguishab...
Anisotropic conductivity imaging with MREIT using equipotential projection algorithm DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2007-09-02) Magnetic resonance electrical impedance tomography (MREIT) is a new medical imaging technique which combines boundary potential measurements of electrical impedance tomography (EIT) and internal current density distribution obtained from magnetic resonance imaging (MRI) to produce conductivity images having high spatial resolution and accuracy. In this study, a novel method of reconstructing images of anisotropic conductivity tensor distribution inside an electrically conducting subject is proposed for MREI...
Magnetic Resonance Electrical Impedance Tomography For Anisotropic Conductivity Imaging Degirmenci, E.; Eyüboğlu, Behçet Murat (2008-11-27) Magnetic Resonance Electrical Impedance Tomography (MREIT) brings high resolution imaging of true conductivity distribution to reality. MREIT images are reconstructed based on measurements of current density distribution and a surface potential value, induced by an externally applied current flow. Since biological tissues may be anisotropic, isotropic conductivity assumption, as it is adopted in most of MREIT reconstruction algorithms, introduces reconstruction inaccuracy. In this study, a novel algorithm i...

Citation Formats

M. S. Özdemir, “Equipotential projection based magnetic resonance electrical impedance tomography (mr-eit) for high resolution conductivity imaging ,” M.S. - Master of Science, Middle East Technical University, 2003.