B1-based SAR reconstruction using contrast source inversion-electric properties tomography (CSI-EPT).
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 [Formula: see text] 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.
Radiotherapy Department, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. e.balidemaj@amc.nl.
Edmond
E
Balidemaj
Radiotherapy Department, University Medical Center, Utrecht University, Utrecht, The Netherlands.
Cornelis A T
CA
van den Berg
Radiotherapy Department, University Medical Center, Utrecht University, Utrecht, The Netherlands.
Astrid L H M W
AL
van Lier
Radiology Department, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Aart J
AJ
Nederveen
Radiotherapy Department, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Lukas J A
LJ
Stalpers
Radiotherapy Department, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Hans
H
Crezee
Circuits and Systems Group, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, The Netherlands.
Rob F
RF
Remis
D003198:Computer Simulation; D004574:Electromagnetic Fields; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010388:Pelvis / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods*
B1 maps; Conductivity; Contrast source inversion (CSI); Electric properties tomography (EPT); Specific absorption rate (SAR)