Improving Specific Absorption Rate Efficiency and Coil Robustness of Self-Decoupled Transmit/Receive Coils by Elevating Feed and Mode Conductors.
Improving Specific Absorption Rate Efficiency and Coil Robustness of Self-Decoupled Transmit/Receive Coils by Elevating Feed and Mode Conductors.
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DOI：
10.3390/s23041800
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发表时间：
2023-02-06
期刊：
影响因子：
--
通讯作者：
Yan X
中科院分区：
文献类型：
--
作者：
Lu M;Zhang X;Chai S;Yan X
自解耦技术最近被提出用于射频 (RF) 线圈阵列设计。在这里，我们提出了一种新颖的几何形状来降低峰值局部比吸收率（SAR）并提高自解耦线圈的鲁棒性。我们首先证明 B1 由臂导体决定，而最大电场和局部 SAR 由自解耦线圈中的馈电导体决定。然后，我们研究 B1、电场、局部 SAR、SAR 效率和线圈鲁棒性如何随着馈电和模式导体的不同提升距离而变化。接下来，在真实人体上进行具有最佳提升距离的自解耦线圈的模拟。最后，制造了具有最佳提升距离的自解耦线圈，并在工作台和 MRI 实验上进行了测试。通过提升馈电导体，自解耦线圈对人体的峰值 10 g 平均 SAR 可降低 34%。通过提升模式导体，可以观察到较少的线圈失配和相对于负载的较小的谐振频移。仿真和实验结果均表明，具有高位导体的线圈可以保持原始自解耦线圈的高元件间隔离度、B1+效率和信噪比。
Self-decoupling technology was recently proposed for radio frequency (RF) coil array designs. Here, we propose a novel geometry to reduce the peak local specific absorption rate (SAR) and improve the robustness of the self-decoupled coil. We first demonstrate that B1 is determined by the arm conductors, while the maximum E-field and local SAR are determined by the feed conductor in a self-decoupled coil. Then, we investigate how the B1, E-field, local SAR, SAR efficiency, and coil robustness change with respect to different lift-off distances for feed and mode conductors. Next, the simulation of self-decoupled coils with optimal lift-off distances on a realistic human body is performed. Finally, self-decoupled coils with optimal lift-off distances are fabricated and tested on the workbench and MRI experiments. The peak 10 g-averaged SAR of the self-decoupled coil on the human body can be reduced by 34% by elevating the feed conductor. Less coil mismatching and less resonant frequency shift with respect to loadings were observed by elevating the mode conductor. Both the simulation and experimental results show that the coils with elevated conductors can preserve the high interelement isolation, B1+ efficiency, and SNR of the original self-decoupled coils.
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