Development of reconstruction algorithms for magnetic resonance-electrical impedance tomography and experimental realization

Download

119448.pdf

Date

2002

Author

Birgül, Özlem

Metadata

Show full item record

Item Usage Stats

148
views

0
downloads

The electrical properties of biological tissues differ among tissues and vary with physiological and pathological state of a solution of bioelectrical field problems. The aim of this study is to reconstruct conductivity images with higher resolution and better accuracy than existing conductivity imaging tech niques. In order to achieve our goal, we proposed a technique named as Mag netic Resonance-Electrical Impedance Tomography (MR-EIT). MR-EIT com bines peripheral voltage measurements of classical Electrical Impedance To mography (EIT) technique with magnetic flux density measurements acquired using Magnetic Resonance Imaging (MRI) technique. Three reconstruction algorithms for MR-EIT are developed and implemented. Proposed algorithms are grouped into two: current density based reconstruction algorithms ( Type-I) and magnetic flux density based reconstruction algorithms {Type-It). Type-I al- iiigorithms require measurement of magnetic flux density in three directions and rotation of the object in the magnet, whereas measurement of only one com ponent of the magnetic flux density for a single rotation is sufficient for Type- II. Different current injection profiles are studied and their performance are compared. Distinguishability analysis is carried out for magnetic flux density measurements. The technique is experimentally realized using 0.15T METU- EE MRI system and several images are reconstructed for phantoms built using saline solution. In the experimental results, a Type-II algorithm is used and the error in reconstructed conductivity is found to be between 4.15% - 17.7% for saline. Comparison of the new technique with conventional EIT reconstruction using simulation data sets exhibits the superiority of MR-EIT.

Subject Keywords

Magnetic resonance imaging, Electrical impedance tomography, Electrophysiology

URI

https://hdl.handle.net/11511/13026

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Data acquisition system for MAET with magnetic field measurements Kaboutari, Keivan; Tetik, Ahmet Onder; Ghalichi, Elyar; Gozu, Mehmet Soner; Zengin, Reyhan; Gençer, Nevzat Güneri (2019-06-01) Magneto-acousto-electrical tomography (MAET) is an imaging modality to image the electrical conductivity of biological tissues. It is based on electrical current induction by using ultrasound under a static magnetic field. The aim of this study is to develop a data acquisition system for MAET based on magnetic field measurements. The static magnetic field is generated by six permanent neodymium magnets. A 16-element linear phased array (LPA) transducer is utilized to generate acoustic pressure waves inside ...
Magnetic resonance conductivity tensor imaging (MRCTİ) at 3 tesla Sadighi, Mehdi; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2014) Electrical conductivity of biological tissues changes with physiological and pathological state of tissue. Therefore, recognizing the changes of the conductivity distribution inside human body, provides unique information about the pathological conditions of internal organs which is not available from other imaging modalities. Magnetic Resonance Electrical Impedance Tomography (MREIT) is an imaging technique to reconstruct the isotropic conductivity distribution of the biological tissues. But most of the bi...
A Programmable current source for magnetic resonance current density imaging (MRCDI) at 3 tesla Göksu, Cihan; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2014) Electrical properties of biological tissues are distinctive between various types of the tissues, and significantly related with the pathological conditions of the tissues. For instance, conductivity images can be used for tumor identification. Besides, current density distribution may provide useful information in research and development of electrical stimulation, electro-surgery, defibrillation, and cardiac pacing devices. Magnetic resonance current density imaging (MRCDI) and magnetic resonance electric...
Dual current injection-magnetic resonance electrical impedance tomography using spatial modulation of magnetization Naji, Nashwan; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2016) Electrical conductivity of biological tissues provides valuable information on physiological and pathological state of tissues. This may provide conductivity imaging a great potential to have diagnostic applications in clinical field. Developing a method that is able to recognize conductivity variations inside human body has received a great attention over the last decades. Magnetic Resonance Electrical Impedance Tomography (MREIT) is an imaging modality that utilizes current injection during magnetic reson...
High resolution imaging of anisotropic conductivity with magnetic resonance electrical impedance tomography (mr-eit) Değirmenci, Evren; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2010) Electrical conductivity of biological tissues is a distinctive property which differs among tissues. It also varies according to the physiological and pathological state of tissues. Furthermore, in order to solve the bioelectric field problems accurately, electrical conductivity information is essential. Magnetic Resonance Electrical Impedance Tomography (MREIT) technique is proposed to image this information with high spatial resolution. However, almost all MREIT algorithms proposed to date assumes isotrop...

Citation Formats

Ö. Birgül, “Development of reconstruction algorithms for magnetic resonance-electrical impedance tomography and experimental realization,” Ph.D. - Doctoral Program, Middle East Technical University, 2002.