title: Experimental validations of in vivo human musculoskeletal tissue conductivity images using MR-based electrical impedance tomography.
abstract: Magnetic resonance (MR)-based electrical impedance tomography (MREIT) is a widely used imaging technique that provides high-resolution conductivity images at DC or below the 1 kHz frequency range. Using an MR scanner, this technique injects imaging currents into the human body and measures induced internal magnetic flux density data. By applying the recent progress of MREIT techniques, such as chemical shift artifact correction, multi-echo pulse sequence, and improved reconstruction algorithm, we can successfully reconstruct conductivity images of the human body. Meanwhile, numerous studies reported that the electrical conductivity of human tissues could be inferred from in vitro or ex vivo measurements of different species. However, in vivo tissues may differ from in vitro and/or ex vivo state due to the complicated tissue responses in living organs. In this study, we performed in vivo MREIT imaging of a human lower extremity and compared the resulting conductivity images with ex vivo biological tissue phantom images. The human conductivity images showed unique contrast between two different types of bones, muscles, subcutaneous adipose tissues, and conductive body fluids. Except for muscles and adipose tissues, the human conductivity images showed a similar pattern when compared with phantom results due to the anisotropic characteristic of muscle and the high conductive fluids in the adipose tissue.
authors.affiliation: Department of Biomedical Engineering, Kyung Hee University, Yongin, Korea.
authors.forename: Woo Chul
authors.initials: WC
authors.lastname: Jeong
authors.forename: Zi Jun
authors.initials: ZJ
authors.lastname: Meng
authors.forename: Hyung Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Oh In
authors.initials: OI
authors.lastname: Kwon
authors.forename: Eung Je
authors.initials: EJ
authors.lastname: Woo
mesh_terms: D000328:Adult; D004553:Electric Conductivity; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007867:Leg Bones; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles; D019047:Phantoms, Imaging; D014054:Tomography
keywords: MREIT; conductivity; lower extremity; magnetic flux density