title: In vivo imaging of electrical properties of an animal tumor model with an 8-channel transceiver array at 7 T using electrical properties tomography.
abstract: OBJECTIVE
  To develop and evaluate a technique for imaging electrical properties ((EPs), conductivity and permittivity) of an animal tumor model in vivo using MRI.
  
  
  METHODS
  Electrical properties were reconstructed from the calculated EP gradient, which was derived using two sets of measured transmit B1magnitude and relative phase maps with the sample and radiofrequency (RF) coil oriented in the positive and negative z-directions, respectively. An eight-channel transceiver microstrip array RF coil fitting the size of the animal was developed for generating and mapping B1fields to reconstruct EPs. The technique was evaluated at 7 tesla using a physical phantom and in vivo on two Copenhagen rats with subcutaneously implanted AT-1 rat prostate cancer on a hind limb.
  
  
  RESULTS
  The reconstructed EPs in the phantom experiment was in good agreement with the target EP map determined by a dielectric probe. Reconstructed conductivity map of the animals revealed the boundary between tumor and healthy tissue consistent with the boundary indicated by T1-weighted MRI.
  
  
  CONCLUSIONS
  A technique for imaging EP of an animal tumor model using MRI has been developed with high sensitivity, accuracy, and resolution, as demonstrated in the phantom experiment. Further animal experiments are needed to demonstrate its translational value for tumor diagnosis. Magn Reson Med 78:2157-2169, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Jiaen
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Yicun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Gregor
authors.initials: G
authors.lastname: Adriany
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.|Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.|Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: John
authors.initials: J
authors.lastname: Bischof
authors.affiliation: Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Pierre-Francois
authors.initials: PF
authors.lastname: Van de Moortele
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.|Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: He
mesh_terms: D000465:Algorithms; D000818:Animals; D004553:Electric Conductivity; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009368:Neoplasm Transplantation; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D011846:Radio Waves; D051381:Rats; D014054:Tomography
keywords: EPT; MRI; RF coil; animal model; bioimpedance; electrical properties tomography; tumor imaging