2019/07/31 by Peter R. S. Stijnman, Stefano Mandija, Stijnman, Peter R. S. +7
Engineering · Medicine · #Advanced MRI Techniques and Applications #Electrical and Bioimpedance Tomography #FOS: Physical sciences #Medical Physics (physics.med-ph) #Microwave Imaging and Scattering Analysis
paper · pdf · doi:10.48550/arxiv.1907.13451
openalex publication_date 2019/07/31 · openalex created_date 2022/07/28 · openalex updated_date 2026/07/28
Magnetic resonance imaging (MRI) based electrical properties tomography (EPT)\nis the quantification of the conductivity and permittivity of different\ntissues. These electrical properties can be obtained through different\nreconstruction methods and can be used as a contrast mechanism. The work\npresented here continues from the two-dimensional CSI-EPT algorithm which was\nshown to work with two-dimensional Matlab based simulations. The existing\nCSI-EPT algorithm is reformulated to use the transceive phase rather than\nrelying on the transceive phase assumption. This is achieved by implementing a\nforward problem, computing the receive phase, into the inverse minimization\nproblem, i.e. retrieving the electrical properties. Furthermore, the radio\nfrequency (RF) shield is numerically implemented to model the RF fields inside\nthe MRI more accurately. Afterwards, the algorithm is tested with\nthree-dimensional FDTD simulations to investigate if the two-dimensional\nCSI-EPT can retrieve the electrical properties for three-dimensional RF fields.\nFinally, an MR experiment with a phantom is performed to show the potential for\nthis method. From the results of the two-dimensional Matlab simulations it is\nseen that CSI-EPT can reconstruct the electrical properties using MRI\naccessible quantities. In the three-dimensional simulations it is observed that\nthe electrical properties are underestimated, nonetheless, CSI-EPT is more\nprecise than the standard Helmholtz based methods. Finally, the first CSI-EPT\nresults using measured data are shown. The results for the reconstruction using\nmeasured data were of the same quality as the results from the FDTD simulation.\n