J-substitution algorithm in magnetic resonance electrical impedance tomography (MREIT): phantom experiments for static resistivity images

Abstract

Recently, a new static resistivity image reconstruction algorithm is proposed utilizing internal current density data obtained by magnetic resonance current density imaging technique. This new imaging method is called magnetic resonance electrical impedance tomography (MREIT). The derivation and performance of J-substitution algorithm in MREIT have been reported as a new accurate and high-resolution static impedance imaging technique via computer simulation methods. In this paper, we present experimental procedures, denoising techniques, and image reconstructions using a 0.3-tesla (T) experimental MREIT system and saline phantoms. MREIT using J-substitution algorithm effectively utilizes the internal current density information resolving the problem inherent in a conventional EIT, that is, the low sensitivity of boundary measurements to any changes of internal tissue resistivity values. Resistivity images of saline phantoms show an accuracy of 6.8%-47.2% and spatial resolution of 64 x 64. Both of them can be significantly improved by using an MRI system with a better signal-to-noise ratio.

Predicting irreversible electroporation-induced tissue damage by means of magnetic resonance electrical impedance tomography

“…The method relies on current-induced magnetic field changes in the sample that are detected via phase shift registration by magnetic resonance imaging 46 , 47 . Next, a MREIT algorithm 48 , 49 (Fig. 2b ), based on iterative solving of the Laplace equation, was employed to calculate a tumor conductivity map and electric field in the tumor by using CDI data along with known tumor geometry and potentials on the electrodes as inputs for the algorithm.…”

Ex Vivo and In Silico Feasibility Study of Monitoring Electric Field Distribution in Tissue during Electroporation Based Treatments

“…MREIT algorithms are in general used for reconstruction of conductivity distribution inside samples [27], [28], although they can also be applied for reconstruction of electric field. MREIT is based on current density imaging (CDI) which is an MRI method for acquiring current density distribution inside samples.…”

Magnetic resonance electrical impedance tomography for measuring electrical conductivity during electroporation

“…MREIT is a relatively new medical imaging modality based on numerical reconstruction of electrical conductivity inside a tissue by means of current density obtained by CDI (Woo et al 1994, Khang et al 2002, Seo and Woo 2011. The MREIT J-substitution algorithm was applied for reconstruction of electrical conductivity in the measurement objects (Kwon et al 2002b, Seo et al 2003a, Khang et al 2002. The algorithm is based on solving Laplace's equation inside a mathematical model of the measurement object M with the corresponding Neumann and Dirichlet boundary conditions on the measurement object outer boundary ∂ Mo and on the electrode boundary ∂ Me+/− , respectively:…”