Performance evaluation of magnetic flux density based magnetic resonance electrical impedance tomography reconstruction algorithms

Download

index.pdf

Date

2009

Author

Eker, Gökhan

Metadata

Show full item record

Item Usage Stats

229
views

73
downloads

Magnetic Resonance Electrical Impedance Tomography (MREIT) reconstructs images of electrical conductivity distribution based on magnetic flux density (B) measurements. Magnetic flux density is generated by an externally applied current on the object and measured by a Magnetic Resonance Imaging (MRI) scanner. With the measured data and peripheral voltage measurements, the conductivity distribution of the object can be reconstructed. There are two types of reconstruction algorithms. First type uses current density distributions to reconstruct conductivity distribution. Object must be rotated in MRI scanner to measure three components of magnetic flux density. These types of algorithms are called J-based reconstruction algorithms. The second type of reconstruction algorithms uses only one component of magnetic flux density which is parallel to the main magnetic field of MRI scanner. This eliminates the need of subject rotation. These types of algorithms are called B-based reconstruction algorithms. In this study four of the B-based reconstruction algorithms, proposed by several research groups, are examined. The algorithms are tested by different computer models for noise-free and noisy data. For noise-free data, the algorithms work successfully. System SNR 30, 20 and 13 are used for noisy data. For noisy data the performance of algorithm is not as satisfactory as noise-free data. Twice differentiation of z component of B (Bz) is used for two of the algorithms. These algorithms are very sensitive to noise. One of the algorithms uses only one differentiation of Bz so it is immune to noise. The other algorithm uses sensitivity matrix to reconstruct conductivity distribution.

Subject Keywords

Electrical engineering., Electronics.

URI

http://etd.lib.metu.edu.tr/upload/12610940/index.pdf
https://hdl.handle.net/11511/19010

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Performance evaluation of current density based magnetic resonance electrical impedance tomography reconstruction algorithms (mr-eit) Boyacıoğlu, Rasim; Eyüboğlu, Behçet Murat; Department of Biomedical Engineering (2009) Magnetic Resonance Electrical Impedance Tomography (MREIT) reconstructs conductivity distribution with internal current density (MRCDI) and boundary voltage measurements. There are many algorithms proposed for the solution of MREIT inverse problem which can be divided into two groups: Current density (J) and magnetic flux density (B) based reconstruction algorithms. In this thesis, J-based MREIT reconstruction algorithms are implemented and optimized with modifications. These algorithms are simulated with f...
The electrical characteristics of antennas in their operational environment Afacan, Gönenç; Tuncay, Birand; Department of Electrical and Electronics Engineering (2007) This thesis investigates the variations of electrical properties of linear antennas mounted on certain platforms, depending on the physical properties of that platform. In this respect, related basic antenna simulations, electromagnetic simulations from primitive to complex models of airframes, and scale model measurements were used. Firstly, electrical properties of monopoles at known environment were examined and basic analyses were performed via an electromagnetic simulation tool, named CST Microwave Stu...
Performance Enhancement of the Single-Phase Series Active Filter by Employing the Load Voltage Waveform Reconstruction and Line Current Sampling Delay Reduction Methods Senturk, Osman S.; Hava, Ahmet Masum (Institute of Electrical and Electronics Engineers (IEEE), 2011-08-01) This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference...
Magnetic resonance current density imaging using one component of magnetic flux density Ersöz, Ali; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2010) Magnetic Resonance Electrical Impedance Tomography (MREIT) algorithms using current density distribution have been proposed in the literature. The current density distribution can be determined by using Magnetic Resonance Current Density Imaging (MRCDI) technique. In MRCDI technique, all three components of magnetic flux density should be measured. Hence, object should be rotated inside the magnet which is not trivial even for small size objects and remains as a strong limitation to clinical applicability o...
Tunable frequency microstrip antennas by rf-mems technology Erdil, Emre; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2005) This thesis presents the design, fabrication, and measurement of tunable frequency microstrip antennas using RF MEMS (Microelectromechanical Systems) technology. The integration of RF MEMS components with radiators enable to implement tunable systems due to the adjustable characteristics of RF MEMS components. In the frame of this thesis, different types of structures have been investigated and designed. The first structure consists of a microstrip patch antenna which is loaded with a microstrip stub whose ...

Citation Formats

G. Eker, “Performance evaluation of magnetic flux density based magnetic resonance electrical impedance tomography reconstruction algorithms,” M.S. - Master of Science, Middle East Technical University, 2009.