Electrical impedance tomography using lorentz fields

Zengin, Reyhan
In this thesis, a novel approach is proposed to image the electrical conductivity properties of biological tissues. This technique is based on electrical current induction using ultrasound together with and applied static magnetic field. Acoustic vibrations are generated via piezoelectric transducers located on the surface of a biological body. To simulate the new technique multiphysics solution is required which couples pressure and electromagnetic equations. The feasibility of the proposed approach is investigated using analytical and numerical techniques. A linear phased array piezoelectric transducer and a single element transducer are used to form pressure distribution in human body/tissue. In the existence of a static magnetic field, the resultant (velocity) current density is sensed by a receiver coil encircling the tissue and used for reconstructing the conductivity distribution. To sense the resultant current density a novel coil configuration is proposed. Truncated Singular Value Decomposition (tSVD) Method is used as a reconstruction algorithm. Results show the potential of this approach as a new, practical and high resolution imaging modality for electrical conductivity imaging.


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...
Design and realization of a hybrid medical imaging system: harmonic motion microwave doppler imaging
Tafreshi, Azadeh Kamali; Gençer, Nevzat Güneri; Department of Electrical and Electronics Engineering (2016)
Harmonic Motion Microwave Doppler Imaging (HMMDI) is a novel imaging modality to image electrical and mechanical properties of body tissues. This modality is recently proposed by the researchers in the METU EEE department for early-stage diagnosis of cancerous tissues. The main goal of this thesis study is to contribute various stages of the HMMDI's development processes. Speci cally, phantom development, dielectric and elastic characterization of the phantoms, experimental system realization, phantom exper...
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...
Magnetohydrodynamic flow imaging of ionic solutions using electrical current injection and MR phase measurements
Eroglu, Hasan H.; Sadighi, Mehdi; Eyüboğlu, Behçet Murat (Elsevier BV, 2019-06-01)
In this study, a method is proposed to image magnetohydrodynamic (MHD) flow of ionic solutions, which is caused by externally injected electrical current to an imaging media, during MRI scans. A multi-physics (MP) model is created by using the electrical current, laminar flow, and MR equations. The conventional spoiled gradient echo MRI pulse sequence with bipolar flow encoding gradients is utilized to encode the MHD flow. Using the MP model and the MRI pulse sequence, relationship between the MHD flow rela...
Analysis of reconstruction performance of magnetic resonance conductivity tensor imaging (MRCTI) using simulated measurements
DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2017-01-01)
Magnetic resonance conductivity tensor imaging (MRCTI) was proposed recently to produce electrical conductivity images of anisotropic tissues. Similar to magnetic resonance electrical impedance tomography (MREIT), MRCTI uses magnetic field and boundary potential measurements obtained utilizing magnetic resonance imaging techniques. MRCTI reconstructs tensor images of anisotropic conductivity whereas MREIT reconstructs isotropic conductivity images. In this study, spatial resolution and linearity of five rec...
Citation Formats
R. Zengin, “Electrical impedance tomography using lorentz fields,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.