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.
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.
Magn Reson Imaging. 2024 Feb;106:77-84. doi: 10.1016/j.mri.2023.11.005. Epub 2023 Nov 7.
The design of radiofrequency (RF) coils is crucial for ultra-high field (UHF) magnetic resonance imaging (MRI) systems. To analyze RF coils, various numerical methods, such as finite-difference time-domain (FDTD) and method of moments (MoM), are usually adopted. In this paper, we present a novel hybrid approach that combines a two-dimensional (2D) FDTD with a three-dimensional (3D) MoM to analyze MRI RF problems. In our algorithm, the MoM is utilized for calculating the coil current, and FDTD is assigned for solving the electromagnetic (EM) fields in the imaging region. The hybrid method achieves superior efficiency and acceptable accuracy than using either method individually. To validate the hybrid method, we analyze an ellipse coil loaded with a uniform phantom and a realistic human head model, with the objective of tailoring the magnetic field intensity by adding a multilayer dielectric pad (DP). The results show an improvement in the magnetic field after optimizing the DP configuration. These simulation studies indicate the potential of the new numerical method for the design and analysis of RF systems for ultra-high field applications.
射频（RF）线圈的设计对于超高磁场（UHF）磁共振成像（MRI）系统至关重要。为了分析 RF 线圈，通常采用各种数值方法，如有限差分时域（FDTD）和矩量法（MoM）。在本文中，我们提出了一种新颖的混合方法，将二维（2D）FDTD 与三维（3D）MoM 相结合，用于分析 MRI RF 问题。在我们的算法中，MoM 用于计算线圈电流，而 FDTD 则用于求解成像区域中的电磁场。与单独使用任何一种方法相比，混合方法具有更高的效率和可接受的准确性。为了验证混合方法，我们分析了一个加载均匀体模和真实人头模型的椭圆线圈，目的是通过添加多层介电垫（DP）来调整磁场强度。结果表明，优化 DP 配置后磁场得到了改善。这些模拟研究表明，新的数值方法在超高场应用中 RF 系统的设计和分析方面具有潜力。
