Induced Current Magnetic Resonance Electrical Conductivity Imaging With Oscillating Gradients

Eroglu H. H., Sadighi M., EYÜBOĞLU B. M.

IEEE TRANSACTIONS ON MEDICAL IMAGING, vol.37, no.7, pp.1606-1617, 2018 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 37 Issue: 7
  • Publication Date: 2018
  • Doi Number: 10.1109/tmi.2018.2795718
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1606-1617
  • Keywords: Electrical impedance tomography, eddy current, gradient coil, induced current, image reconstruction, low frequency phase, magnetic resonance imaging, IMPEDANCE TOMOGRAPHY
  • Middle East Technical University Affiliated: Yes


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.