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An inverse method for designing loaded RF coils in MRI
journal contribution
posted on 2023-05-16, 18:08 authored by While, PT, Lawrence ForbesLawrence Forbes, Crozier, SRadio-frequency (RF) coils are designed such that they induce homogeneous magnetic fields within some region of interest within a magnetic resonance imaging (MRI) scanner. Loading the scanner with a patient disrupts the homogeneity of these fields and can lead to a considerable degradation of the quality of the acquired image. In this paper, an inverse method is presented for designing RF coils, in which the presence of a load (patient) within the MRI scanner is accounted for in the model. To approximate the finite length of the coil, a Fourier series expansion is considered for the coil current density and for the induced fields. Regularization is used to solve this ill-conditioned inverse problem for the unknown Fourier coefficients. That is, the error between the induced and homogeneous target fields is minimized along with an additional constraint, chosen in this paper to represent the curvature of the coil windings. Smooth winding patterns are obtained for both unloaded and loaded coils. RF fields with a high level of homogeneity are obtained in the unloaded case and a limit to the level of homogeneity attainable is observed in the loaded case. © 2006 IOP Publishing Ltd.
Funding
Australian Research Council
History
Publication title
Measurement Science and TechnologyVolume
17Issue
9Pagination
2506-2518ISSN
0957-0233Department/School
School of Natural SciencesPublisher
IOP Publishing LtdPlace of publication
Bristol, EnglandRepository Status
- Restricted