Experimental results for 2D magnetic resonance electrical impedance tomography (MR-EIT) using magnetic flux density in one direction

Abstract

Magnetic resonance electrical impedance tomography (MR-EIT) is an emerging imaging technique that reconstructs conductivity images using magnetic flux density measurements acquired employing MRI together with conventional EIT measurements. In this study, experimental MR-EIT images from phantoms with conducting and insulator objects are presented. The technique is implemented using the 0.15 T Middle East Technical University MRI system. The dc current method used in magnetic resonance current density imaging is adopted. A reconstruction algorithm based on the sensitivity matrix relation between conductivity and only one component of magnetic flux distribution is used. Therefore, the requirement for object rotation is eliminated. Once the relative conductivity distribution is found, it is scaled using the peripheral voltage measurements to obtain the absolute conductivity distribution. Images of several insulator and conductor objects in saline filled phantoms are reconstructed. The L2 norm of relative error in conductivity values is found to be 13%, 17% and 14% for three different conductivity distributions.

Magnetic resonance electrical impedance tomography at 3 tesla field strength

“…In previous MREIT experimental studies (10 -12), the biggest problems were object rotations inside the magnet to acquire the three components of the internal magnetic field data, and low SNR of reconstructed images. However, new MREIT reconstruction algorithms were recently introduced, along with phantom imaging results obtained without any object rotations (13)(14)(15).…”

“…In previous MREIT experimental studies (10 -12), the biggest problems were object rotations inside the magnet to acquire the three components of the internal magnetic field data, and low SNR of reconstructed images. However, new MREIT reconstruction algorithms were recently introduced, along with phantom imaging results obtained without any object rotations (13)(14)(15).In this work we present some results of MREIT phantom imaging experiments performed with the harmonic B z algorithm and a 3.0 Tesla MRI system. After briefly introducing the fundamental principle of the conductivity image reconstruction algorithm, we present the experimental results of the conductivity imaging performance evaluation.…”

A new magnetic resonance electrical impedance tomography (MREIT) algorithm: the RSM-MREIT algorithm with applications to estimation of human head conductivity

“…However, in computer simulations, some undesirable side effects are observed which affect the accuracy of reconstructed images. Birgül et al (Birgül et al, 2003b) reported a MREIT phantom experiment using a two-dimensional (2D) reconstruction algorithm, which is based on the sensitivity matrix relation between conductivity and one component of magnetic flux distribution. İder and Onart (İder and Onart, 2004) reported a new MREIT algorithm using B z to reconstruct 3D conductivity distribution of the object.…”

Equivalent Isotropic Conductivity Image Reconstruction in MREIT

“…Numerous conductivity image reconstruction algorithms have been developed and most of them assume an isotropic conductivity distribution [5][6][7][8][9][10][11][12][13][14]. Almost all reported experimental MREIT studies using phantoms also have assumed isotropic conductivity distributions [8,13,15,16].…”

“…Almost all reported experimental MREIT studies using phantoms also have assumed isotropic conductivity distributions [8,13,15,16]. However, conductivities of certain biological tissues, for example white matters in the brain, are known to be anisotropic especially at low frequency.…”