Electrical conductivity images of biological tissue phantoms in MREIT.

We present cross-sectional conductivity images of two biological tissue phantoms. Each of the cylindrical phantoms with both diameter and height of 140 mm contained chunks of biological tissues such as bovine tongue and liver, porcine muscle and chicken breast within a conductive agar gelatin as the background medium. We attached four recessed electrodes on the sides of the phantom with equal spacing among them. Injecting current pulses of 480 or 120 mA ms into the phantom along two different directions, we measured the z-component Bz of the induced magnetic flux density B=(Bx, By, Bz) with a magnetic resonance electrical impedance tomography (MREIT) system based on a 3.0 T MRI scanner. Using the harmonic Bz algorithm, we reconstructed cross-sectional conductivity images from the measured Bz data. Reconstructed images clearly distinguish different tissues in terms of both their shapes and conductivity values. In this paper, we experimentally demonstrate the feasibility of the MREIT technique in producing conductivity images of different biological soft tissues with a high spatial resolution and accuracy when we use a sufficient amount of the injection current.

[1]  M.L.G. Joy.  MR current density and conductivity imaging: the state of the Aart , 2004, The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[2]  Byung Il Lee,et al.  Three-dimensional forward solver and its performance analysis for magnetic resonance electrical impedance tomography (MREIT) using recessed electrodes. , 2003, Physics in medicine and biology.

[3]  B Murat Eyüboğlu,et al.  Current constrained voltage scaled reconstruction (CCVSR) algorithm for MR-EIT and its performance with different probing current patterns. , 2003, Physics in medicine and biology.

[4]  D Miklavcic,et al.  Electric current density imaging of mice tumors , 1997, Magnetic resonance in medicine.

[5]  R M Henkelman,et al.  Measurement of nonuniform current density by magnetic resonance. , 1991, IEEE transactions on medical imaging.

[6]  William R B Lionheart,et al.  Uniqueness and reconstruction in magnetic resonance-electrical impedance tomography (MR-EIT). , 2003, Physiological measurement.

[7]  R. Panerai,et al.  Variability of time-domain indices of dynamic cerebral autoregulation. , 2003, Physiological measurement.

[8]  Ohin Kwon,et al.  Magnetic resonance electrical impedance tomography at 3 tesla field strength , 2004, Magnetic resonance in medicine.

[9]  John G. Webster,et al.  Electrical Impedance Tomography , 1991 .

[10]  B.I. Lee,et al.  Conductivity images of biological tissue phantoms using a 3.0 tesla MREIT system , 2004, The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[11]  T.-S. Kim,et al.  Diffusion PDE-based denoising technique for magnetic resonance electrical impedance tomography , 2004, The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[12]  David Isaacson,et al.  Electrical Impedance Tomography , 2002, IEEE Trans. Medical Imaging.

[13]  Y Ziya Ider,et al.  Algebraic reconstruction for 3D magnetic resonance-electrical impedance tomography (MREIT) using one component of magnetic flux density. , 2004, Physiological measurement.

[14]  K. Boone,et al.  Imaging with electricity: report of the European Concerted Action on Impedance Tomography. , 1997, Journal of medical engineering & technology.

[15]  Ohin Kwon,et al.  Static conductivity imaging using variational gradient Bz algorithm in magnetic resonance electrical impedance tomography. , 2004, Physiological measurement.

[16]  Ohin Kwon,et al.  Electrical conductivity imaging using gradient Bz decomposition algorithm in magnetic resonance electrical impedance tomography (MREIT) , 2004, IEEE Trans. Medical Imaging.

[17]  Byung Il Lee,et al.  Conductivity and current density image reconstruction using harmonic Bz algorithm in magnetic resonance electrical impedance tomography. , 2003, Physics in medicine and biology.

[18]  Byung Il Lee,et al.  Reconstruction of current density distributions in axially symmetric cylindrical sections using one component of magnetic flux density: computer simulation study. , 2003, Physiological measurement.

[19]  M Seeck,et al.  Functional MRI with simultaneous EEG recording: Feasibility and application to motor and visual activation , 2001, Journal of magnetic resonance imaging : JMRI.

[20]  Sartaj Sahni,et al.  Leaf sequencing algorithms for segmented multileaf collimation. , 2003, Physics in medicine and biology.

[21]  Byung Il Lee,et al.  J-substitution algorithm in magnetic resonance electrical impedance tomography (MREIT): phantom experiments for static resistivity images , 2002, IEEE Transactions on Medical Imaging.

[22]  Ohin Kwon,et al.  Reconstruction of conductivity and current density images using only one component of magnetic field measurements , 2003, IEEE Transactions on Biomedical Engineering.

[23]  Y. Birgül,et al.  Use of the Magnetic Field Generated by the Internal Distribution of Injected Currents for Electrical Impedance Tomography (MR-EIT) , 1998 .

[24]  Ohin Kwon,et al.  Image reconstruction of anisotropic conductivity tensor distribution in MREIT: computer simulation study. , 2004, Physics in medicine and biology.

[25]  Eung Je Woo,et al.  Impedance tomography using internal current density distribution measured by nuclear magnetic resonance , 1994, Optics & Photonics.

[26]  M. H. Cho,et al.  Static resistivity image of a cubic saline phantom in magnetic resonance electrical impedance tomography (MREIT). , 2003, Physiological measurement.

[27]  K.F. Hasanov,et al.  A new approach to current density impedance imaging , 2004, The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[28]  Ohin Kwon,et al.  Magnetic resonance electrical impedance tomography (MREIT): simulation study of J-substitution algorithm , 2002, IEEE Transactions on Biomedical Engineering.

[29]  R. Henkelman,et al.  Sensitivity of magnetic-resonance current-density imaging , 1992 .