A hybrid FDTD/MoM algorithm with a non-uniform grid for MRI RF coil design

Yang Liu; Qiuliang Wang; Feng Liu

doi:10.1016/j.mri.2022.10.008

A hybrid FDTD/MoM algorithm with a non-uniform grid for MRI RF coil design

Magn Reson Imaging. 2023 Feb:96:75-84. doi: 10.1016/j.mri.2022.10.008. Epub 2022 Oct 18.

Authors

Yang Liu¹, Qiuliang Wang², Feng Liu³

Affiliations

¹ Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: qiuliang@mail.iee.ac.cn.
³ School of Information Technology and Electrical Engineering, The University of Queensland, St. Lucia, Brisbane, Qld. 4072, Australia.

PMID: 36265697
DOI: 10.1016/j.mri.2022.10.008

Abstract

In ultra-high-field (UHF) magnetic resonance imaging (MRI) applications, the design and analysis of high-frequency radio frequency (RF) coils requires full-wave electromagnetic (EM) methods that can handle complex field-tissue interactions. Using a Huygens' equivalent surface, the Method of Moments (MoM) and the Finite-Difference Time-Domain (FDTD) algorithm can be combined to accurately model the high-frequency RF coils. In previous research, a uniform FDTD mesh structure was considered, providing a compromised solution for coil-tissue interactions. This paper proposes a hybrid FDTD/MoM algorithm with non-uniform meshes. The fine mesh domain is set at the Huygens' surface, and the other domain uses coarse meshes. The proposed algorithms are strictly validated, and their computational performance is compared against conventional methods. Results show that the new algorithm can improve the calculation efficiency without losing accuracy. Specifically, compared with the uniform FDTD method, the numerical difference between both hybrid methods remains at 3.2%. Still, the calculation time of the non-uniform grid algorithm is reduced by 64.2%, demonstrating the effectiveness of the new algorithm for modeling RF coils for UHF-MRI applications.

Keywords: FDTD; Hybrid method; MoM; Numerical analysis; RF coil.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algorithms*
Electromagnetic Fields
Magnetic Resonance Imaging* / methods
Phantoms, Imaging
Radio Waves