title: Simultaneous imaging of dual-frequency electrical conductivity using a combination of MREIT and MREPT.
abstract: OBJECTIVE
  To propose a single magnetic resonance scan conductivity imaging technique providing dual-frequency characteristics of tissue conductivity.
  
  
  METHODS
  Using a modified spin-echo pulse sequence, the magnetic flux density induced by externally injected currents and the B1+ phase map with injected current effects removed were acquired simultaneously. The low-frequency conductivity was reconstructed from the measured magnetic flux density by the projected current density method, while the high-frequency conductivity was reconstructed using the B1+ maps. Three different conductivity phantoms were used to demonstrate low- and high-frequency conductivity characteristics.
  
  
  RESULTS
  A conductivity spectrum at two frequencies was successfully acquired with the proposed scheme. Magnetic resonance electrical impedance tomography is advantageous for seeing an anomaly itself wrapped with a thin insulating membrane. In addition, if the membrane is porous, the membrane property can be quantitatively visualized with magnetic resonance electrical impedance tomography. Magnetic resonance electrical properties tomography does not detect such membranes, which enable it to probe things inside an insulating membrane.
  
  
  CONCLUSIONS
  Considering these pros and cons and also the fact that the conductivity of biological tissue changes with frequency, a dual-frequency conductivity imaging incorporating both magnetic resonance electrical impedance tomography and magnetic resonance electrical properties tomography in future animal and human experiments is suggested.
authors: Department of Biomedical Engineering, Kyung Hee University, Korea.
authors: Hyung Joong
authors: HJ
authors: Kim
authors: Woo Chul
authors: WC
authors: Jeong
authors: Saurav Z K
authors: SZ
authors: Sajib
authors: Min-Oh
authors: MO
authors: Kim
authors: Oh In
authors: OI
authors: Kwon
authors: Eung
authors: E
authors: Je Woo
authors: Dong-Hyun
authors: DH
authors: Kim
mesh_terms: D058266:Dielectric Spectroscopy / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D064847:Multimodal Imaging / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: B1 map; MREIT; MREPT; conductivity image; conductivity spectrum; magnetic flux density