In this letter, we evaluate antenna designs for ultra-high frequency and field (UHF) human brain magnetic resonance imaging (MRI) at 10.5 tesla (T). Although MRI at such UHF is expected to provide major signal-to-noise gains, the frequency of interest, 447 MHz, presents us with challenges regarding improved B1+ efficiency, image homogeneity, specific absorption rate (SAR), and antenna element decoupling for array configurations. To address these challenges, we propose the use of both monopole and dipole antennas in a novel hybrid configuration, which we refer to as a mono-dipole hybrid antenna (MDH) array. Compared to an 8-channel dipole antenna array of the same dimensions, the 8-channel MDH array showed an improvement in decoupling between adjacent array channels, as well as ∼18% higher B1+ and SAR efficiency near the central region of the phantom based on simulation and experiment. However, the performances of the MDH and dipole antenna arrays were overall similar when evaluating a human model in terms of peak B1+ efficiency, 10 g SAR, and SAR efficiency. Finally, the concept of an MDH array showed an advantage in improved decoupling, SAR, and B1+ near the superior region of the brain for human brain imaging.

中文翻译：

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用于 10.5 特斯拉人脑成像的单极子和偶极子混合天线阵列


在这封信中，我们评估了 10.5 特斯拉 (T) 超高频场 (UHF) 人脑磁共振成像 (MRI) 的天线设计。尽管这种 UHF 的 MRI 有望提供主要的信噪比增益，但我们感兴趣的频率 447 MHz 给我们带来了有关提高 B1+ 效率、图像均匀性、比吸收率 (SAR) 和阵列天线元件去耦的挑战配置。为了应对这些挑战，我们建议在新型混合配置中使用单极子和偶极子天线，我们将其称为单偶极子混合天线（MDH）阵列。与相同尺寸的 8 通道偶极子天线阵列相比，8 通道 MDH 阵列在相邻阵列通道之间的去耦方面表现出改进，并且基于模型中心区域附近的 B1+ 和 SAR 效率提高了约 18%模拟和实验。然而，在评估人体模型的峰值 B1+ 效率、10 g SAR 和 SAR 效率时，MDH 和偶极天线阵列的性能总体相似。最后，MDH 阵列的概念在人脑成像的大脑上部区域附近显示出改善去耦、SAR 和 B1+ 的优势。