Magnetic resonance current density imaging using one component of magnetic flux density

Download

index.pdf

Date

2010

Author

Ersöz, Ali

Metadata

Show full item record

Item Usage Stats

143
views

97
downloads

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 of the technique. In this thesis, 2D MRCDI problem is investigated in detail and an analytical relation is found between Bz, Jx and Jy. This study makes it easy to understand the behavior of Bz due to changes in Jx and Jy. Furthermore, a novel 2D MRCDI reconstruction algorithm using one component of B is proposed. Iterative FT-MRCDI algorithm is also implemented. The algorithms are tested with simulation and experimental models. In simulations, error in the reconstructed current density changes between 0.27% - 23.00% using the proposed algorithm and 7.41% - 37.45% using the iterative FT-MRCDI algorithm for various SNR levels. The proposed algorithm is superior to the iterative FT-MRCDI algorithm in reconstruction time comparison. In experimental models, the classical MRCDI algorithm has the best reconstruction performance when the algorithms are compared by evaluating the reconstructed current density images perceptually. However, the J-substitution algorithm reconstructs the best conductivity image by using J obtained from the proposed algorithm. Finally, the iterative FT-MRCDI algorithm shows the best performance when the reconstructed current density images are verified by using divergence theorem.

Subject Keywords

Electrical and Electronics Engineering.

URI

http://etd.lib.metu.edu.tr/upload/12612164/index.pdf
https://hdl.handle.net/11511/19735

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Design of an electromagnetic classifier for spherical targets Ayar, Mehmet; Sayan, Gönül; Department of Electrical and Electronics Engineering (2005) This thesis applies an electromagnetic feature extraction technique to design electromagnetic target classifiers for conductors, dielectrics and dielectric coated conductors using their natural resonance related late-time scattered responses. Classifier databases contain scattered data at only a few aspects for each candidate target. The targets are dielectric spheres of varying sizes and refractive indices, perfectly conducting spheres varying sizes and dielectric coated conducting spheres of varying refra...
Performance evaluation of magnetic flux density based magnetic resonance electrical impedance tomography reconstruction algorithms Eker, Gökhan; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2009) 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 de...
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...
Design and implementation of microwave lumped components and system integration using MEMS technology Temoçin, Engin Ufuk; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006) This thesis presents the design and fabrication of coplanar waveguide to microstrip transitions and planar spiral inductors, and the design of metal-insulator-metal capacitors, a planar band-pass, and a low-pass filter structures as an application for the inductors and capacitors using the RF MEMS technology. This thesis also includes a packaging method for RF MEMS devices with the use of “benzocyclobutene” as bonding material. The transition structures are formed by four different methods between coplanar ...
Magnetic resonance current density imaging using one component of magnetic flux density Ersoz, Ali; Eyüboğlu, Behçet Murat (2013-03-01) Current density distribution generated inside a volume conductor by externally applied currents can be calculated by using spatial distribution of its magnetic flux density, . The imaging modality used to reconstruct images of the current density distribution is known as magnetic resonance current density imaging (MRCDI). In MRCDI, spatial distribution of the current-induced magnetic flux density is measured on a magnetic resonance imaging (MRI) platform. Calculation of current density distribution from mag...

Citation Formats

A. Ersöz, “Magnetic resonance current density imaging using one component of magnetic flux density,” M.S. - Master of Science, Middle East Technical University, 2010.