高场磁共振大视野高信噪比射频线圈关键问题研究

High field magnetic resonance imaging technologies are confronted with the problems of low signal to noise ratio (SNR) and insufficient resolution in head and neck range imaging. The multi-channel RF coil with large field of view (FOV) and high SNR is the key to solve the above problems. There are some problems in fast analysis, large FOV and high SNR currently for multi-channel RF coil. In this study, the fast analysis method and performance evaluation for multi-channel RF coil, imaging reconstruction with large FOV and high SNR, decoupling of multi-channel RF coil will be investigated. Based on the preliminary studies, the fast simulation method and performance evaluation will be achieved by improving multilevel matrix decomposition method, which based on method of moment; the imaging with large FOV and high SNR will be obtained based on the theory of coupling among channels, and the coupling will be removed or decreased by combing noise covariance matrix in imaging reconstruction. In this study, a head-neck RF coil with more than 20 channels will be designed by simulation. The results of this study will greatly promote the high field magnetic resonance imaging technology in clinical application.

高场磁共振成像技术在头颈部大视野检查范围成像面临信噪比低和分辨率不足的问题。采用具有大视野高信噪比多通道射频线圈是解决上述问题的关键。目前多通道射频线圈在快速分析、大视野高信噪比成像方面存在不足。本课题主要研究多通道射频线圈快速分析和性能评估方法、大视野和高信噪比图像重建以及多通道射频线圈去耦问题。在前期工作基础上，通过改进基于矩量法的多层矩阵分解算法来实现多通道射频线圈的快速仿真分析和性能评估；基于多通道线圈耦合理论，实现大视野成像方法和高信噪比图像重建；利用噪声耦合矩阵，实现多通道线圈的解耦；通过仿真设计，研制不少于20通道的头颈一体化线圈。本项目研究结果将大大促进高场磁共振成像技术的临床应用。

首先基于惠更斯等效面源和妈妈/ FDTD建立磁共振多通道射频线圈模型的快速分析方法和设计平台，服务于射频线圈设计，性能评估和结构优化;次年开发并设计出20通道（8通道颈动脉线圈和12通道头部线圈）大FOV射频线圈，完善射频线圈去耦合方法，并为多通道线圈实现高分辨大FOV成像提供基础和技术支撑;于2017年更进一步设计并实现32通道（8通道颈动脉线圈和24通道头部线圈）高信噪比大FOV射频线圈，实现头颈动脉血管壁高分辨成像，采集大量临床数据，为实现临床医学转化提供基础数据。