An Efficient Methodology for the Analysis of Dielectric Shimming Materials in Magnetic Resonance Imaging

Jeroen H.F. Van Gemert, Wyger Brink, Andrew Webb, Rob Remis

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

Interference effects in the transmit $B_{1}^{+}$ field can severely degrade the image quality in high-field Magnetic Resonance Imaging (MRI). High-permittivity pads are increasingly used to counteract these effects, but designing such pads is not trivial. In this paper, we present an efficient solution methodology for this dielectric RF shimming problem. By exploiting the fact that dielectric pads form a low rank perturbation of a large-scale background model, we are able to efficiently compute $B_{1}^{+}$ fields that correspond to a wide range of different pad realizations. This allows us to efficiently design dielectric pads that eliminate the $B_{1}^{+}$ -interference effects of high-field MRI. We show that significant speed up factors can be achieved compared with traditional field simulation approaches and we validate our approach against measurements. Measured and simulated field responses are in good agreement with each other indicating that the proposed solution methodology enables us to efficiently analyze dielectric pads in realistic MRI measurement settings.
Original languageEnglish
Pages (from-to)666-673
Number of pages8
JournalIEEE Transactions on Medical Imaging
Volume36
Issue number2
DOIs
Publication statusPublished - 2017

Keywords

  • B⁺₁ fields
  • dielectric shimming …
  • high-permittivity pads
  • magnetic resonance imaging
  • Sherman–Morrison–Woodbury formula

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