Induced Current Magnetic Resonance Electrical Conductivity Imaging With Oscillating Gradients

Date

2018-07-01

Author

Eroglu, Hasan H.
Sadighi, Mehdi
Eyüboğlu, Behçet Murat

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In this paper, induced current magnetic resonance electrical impedance tomography (ICMREIT) by means of current induction due to time-varying gradient fields of magnetic resonance imaging (MRI) systems is proposed. Eddy current and secondary magnetic flux density distributions are calculated for a numerical model composed of a z-gradient coil and a cylindrical conductor. An MRI pulse sequence is developed for the experimental evaluation of ICMREIT on a 3T MRI scanner. A relationship between the secondary magnetic flux density and the low-frequency (LF) MR phase is formulated. Characteristics of the LF phase, the eddy current, and the reconstructed conductivity distributions based on the simulated and the physical measurements are in agreement. Geometric shifts, which may contaminate the LF phase measurements, are not observed in the MR magnitude images. Low sensitivity of the LF phase measurements is a major limitation of ICMREIT towards clinical applications. The reconstructed conductivity images are rough estimates of true conductivity distribution of the experimental phantoms. Although the experimental results show that ICMREIT is safe and potentially applicable, its measurement sensitivity and reconstruction accuracy need to be optimized in order to improve the technique towards clinical applications.

Subject Keywords

Electrical impedance tomography, Eddy current, Gradient coil, Induced current, Image reconstruction, Low frequency phase, Magnetic resonance imaging

URI

https://hdl.handle.net/11511/37780

Journal

IEEE TRANSACTIONS ON MEDICAL IMAGING

DOI

https://doi.org/10.1109/tmi.2018.2795718

Collections

Department of Electrical and Electronics Engineering, Article

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Enhancing induced current magnetic resonance electrical impedance tomography ICMREIT image reconstruction NAJI, NASHWAN; EROĞLU, HASAN HÜSEYİN; SÜMSER, KEMAL; SADIGHI, MEHDI; Eyüboğlu, Behçet Murat (2016-02-15) Induced Current Magnetic Resonance Electrical Impedance Tomography (ICMREIT) is an emerging imaging methodology that utilizes Magnetic Resonance Imaging (MRI) techniques to visualize the electrical conductivity as a new contrast. In ICMREIT, by fast switching of gradient fields of Magnetic Resonance (MR) system eddy currents are induced in the imaging volume. The secondary magnetic field generated by the induced eddy currents can be extracted from the MR phase images. Image reconstruction algorithms then us...

Citation Formats

H. H. Eroglu, M. Sadighi, and B. M. Eyüboğlu, “Induced Current Magnetic Resonance Electrical Conductivity Imaging With Oscillating Gradients,” IEEE TRANSACTIONS ON MEDICAL IMAGING, pp. 1606–1617, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37780.