Measurement of AC magnetic field distribution using magnetic resonance imaging

Date

1997-10-01

Author

Ider, YZ
Muftuler, LT

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

296
views

0
downloads

Electric currents are applied to body in numerous applications in medicine such as electrical impedance tomography, cardiac defibrillation, electrocautery, and physiotherapy. If the magnetic field within a region is measured, the currents generating these fields can be calculated using the curl operator. In this study, magnetic fields generated within a phantom by currents passing through an external wire is measured using a magnetic resonance imaging (MRI) system, A pulse sequence that is originally designed for mapping static magnetic field inhomogeneity is adapted, AC current in the form of a burst sine wave is applied synchronously with the pulse sequence, The frequency of the applied current is in the audio range with an amplitude of 175-mA rms, It is shown that each voxel value of sequential images obtained by the proposed pulse sequence is modulated similar to a single-tone broadband frequency modulated (FM) waveform with the ac magnetic field strength determining the modulation index, An algorithm is developed to calculate the ac magnetic field intensity at each voxel using the frequency spectrum of the voxel signal, Experimental results show that the proposed algorithm can be used to calculate ac magnetic field distribution within a conducting sample that is placed in an MRI system.

Subject Keywords

Current density imaging, Magnetic field measurement, Magnetic resonance imaging

URI

https://hdl.handle.net/11511/64744

Journal

IEEE TRANSACTIONS ON MEDICAL IMAGING

DOI

https://doi.org/10.1109/42.640752

Collections

Department of Electrical and Electronics Engineering, Article

Suggestions

OpenMETU
Core

Realization of magnetic resonance current density imaging at 3 Tesla, Göksu, Cihan; SADIGHI, MEHDI; Eyüboğlu, Behçet Murat (2014-08-26) Magnetic Resonance Current Density Imaging (MRCDI) is an imaging modality, which reconstructs electrical current density distribution inside a material by using Magnetic Resonance Imaging (MRI) techniques. In this study, a current source with maximum current injection capability of 224.7mA, under 1k Omega resistive load is used. Experiments are performed with a 2D uniform phantom, in which a current steering insulator is inserted. Magnetic flux density distributions are measured, and current density images ...
Magnetohydrodynamic Flow Imaging Using Spin-Echo Pulse Sequence Eroğlu, Hasan Hüseyin; SADIGHI, MEHDI; Eyüboğlu, Behçet Murat (2019-04-24) In this study, magnetohydrodynamic (MHD) flow of conductive liquids due to injection of electrical current during magnetic resonance imaging (MRI) is investigated. A spin-echo based MRI pulse sequence is proposed to image the MHD flow. Magnetic resonance (MR) phase effects of the MHD flow is related to the MRI pulse parameters and injected current. Average velocity distributions of the MHD flow are reconstructed using the MR phase images. The method is validated by numerical simulations. The reconstruction ...
Induced Current Magnetic Resonance Electrical Impedance Tomography with z-Gradient Coil Eroglu, Hasan H.; Eyuboglu, Murat (2014-08-30) Magnetic Resonance Electrical Impedance Tomography (MREIT) is a medical imaging method that provides images of electrical conductivity at low frequencies (0-1 kHz). In MREIT, electrical current is applied to the body via surface electrodes and corresponding magnetic flux density is measured by means of Magnetic Resonance (MR) phase imaging techniques. By utilizing the magnetic flux density measurements and surface potential measurements images of true conductivity distribution can be reconstructed. In order...
Experimental and mathematical investigation of mass transfer in food andhydrogel systems using magnetic resonance imaging and NMR relaxometry Çıkrıkcı, Sevil; Öztop, Halil Mecit; Department of Food Engineering (2019) Nuclear magnetic resonance (NMR) and Magnetic Resonance Imaging (MRI) are well-known non-invasive characterization methods used in a wide range of areas; from medical to food applications. NMR experiments are conducted either through spectroscopy with high resolution systems or with relaxometery (Time Domain NMR) through mid or low field systems. Time domain NMR is primarily based on relaxation times and diffusion measurements from the signal coming from the whole sample while MRI enables to visualize the i...
RF Coil Design for MRI Applications in Inhomogeneous Main Magnetic Fields Yılmaz, Ayşen; Eyueboglu, B. M. (2006-09-01) Conventional Magnetic Resonance Imaging (MRI) techniques require homogeneous main magnetic fields. However, MRI applications that are executed in inhomogenous main magnetic fields have been developed in recent years. In this study, RF coil geometries are designed for MRI applications in inhomogeneous magnetic fields. Method of moments is used to obtain the current density distribution on a predefined surface that can produce a desired magnetic field, which is perpendicular to the given inhomogenous main mag...

Citation Formats

Y. Ider and L. Muftuler, “Measurement of AC magnetic field distribution using magnetic resonance imaging,” IEEE TRANSACTIONS ON MEDICAL IMAGING, pp. 617–622, 1997, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/64744.