B1-based SAR reconstruction using contrast source inversion–electric properties tomography (CSI-EPT)

• Published in: Medical & biological engineering & computing Vol. 55; no. 2; pp. 225 - 233
• Main Authors: Balidemaj, Edmond, van den Berg, Cornelis A. T., van Lier, Astrid L. H. M. W., Nederveen, Aart J., Stalpers, Lukas J. A., Crezee, Hans, Remis, Rob F.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2017; Springer Nature B.V
• Subjects: Approximation; Assessments; Biomedical and Life Sciences; Biomedical engineering; Biomedical Engineering and Bioengineering; Biomedicine; Boundary conditions; Coiling; Computation; Computer Applications; Computer Simulation; Electric currents; Electric properties; Electromagnetic Fields; Electromagnetics; Female; Finite difference time domain method; Human Physiology; Humans; Image Processing, Computer-Assisted - methods; Imaging; Magnetic Resonance Imaging - methods; Mathematical models; Methods; Original; Original Article; Pelvis - diagnostic imaging; Permeability; Planes; Radiation therapy; Radiology; Reconstruction; Reproducibility of Results; Simulation; Studies; Tomography; Tomography - methods; Conductivity; Contrast source inversion (CSI); Specific absorption rate (SAR); B1 maps; Electric properties tomography (EPT)
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/s11517-016-1497-6

Specific absorption rate (SAR) assessment is essential for safety purposes during MR acquisition. Online SAR assessment is not trivial and requires, in addition, knowledge of the electric tissue properties and the electric fields in the human anatomy. In this study, the potential of the recently developed CSI-EPT method to reconstruct SAR distributions is investigated. This method is based on integral representations for the electromagnetic field and attempts to reconstruct the tissue parameters and the electric field strength based on B 1 + field data only. Full three-dimensional FDTD simulations using a female pelvis model are used to validate two-dimensional CSI reconstruction results in the central transverse plane of a 3T body coil. Numerical experiments demonstrate that the reconstructed SAR distributions are in good agreement with the SAR distributions as determined via 3D FDTD simulations and show that these distributions can be computed very efficiently in the central transverse plane of a body coil with the two-dimensional approach of CSI-EPT.