Journal of Biomedical Engineering Research (대한의용생체공학회:의공학회지)

The Korean Society of Medical and Biological Engineering (대한의용생체공학회)
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Improved Current Source Design to Measure Induced Magnetic Flux Density Distributions in MREIT

  • Oh Tong-In (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University) ;
  • Cho Young (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University) ;
  • Hwang Yeon-Kyung (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University) ;
  • Oh Suk-Hoon (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University) ;
  • Woo Eung-Je (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University) ;
  • Lee Soo-Yeol (Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University)
  • Published : 2006.02.01
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Abstract

Injecting currents into an electrically conducting subject, we may measure the induced magnetic flux density distributions using an MRI scanner. The measured data are utilized to reconstruct cross-sectional images of internal conductivity and current density distributions in Magnetic Resonance Electrical Impedance Tomography (MREIT). Injection currents are usually provided in a form of mono-polar or bi-polar pulses synchronized with an MR pulse sequence. Given an MRI scanner performing the MR phase imaging to extract the induced magnetic flux density data, the current source becomes one of the key parts determining the signal-to-noise ratio (SNR) of the measured data. Since this SNR is crucial in determining the quality of reconstructed MREIT images, special care must be given in the design and implementation of the current source. This paper describes a current source design for MREIT with features including interleaved current injection, arbitrary current waveform, electrode switching to discharge any stored charge from previous current injections, optical isolation from an MR spectrometer and PC, precise current injection timing control synchronized with any MR pulse sequence, and versatile PC control program. The performance of the current source was verified using a 3T MRI scanner and saline phantoms.

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References

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