The monopole coil and loop coil have orthogonal radiofrequency (RF) fields and thus are intrinsically decoupled electromagnetically if they are laid out appropriately. In this study, we proposed a hybrid monopole/loop technique which could combine the advantages of both loop arrays and monopole arrays. To investigate this technique, a hybrid RF coil array containing four monopole channels and four loop channels was developed for human head magnetic resonance (MR) imaging at 7 T. In vivo MR imaging and g-factor results using monopole-only channels, loop-only channels and all channels of the hybrid array were acquired and evaluated. Compared with the monopole-only and loop-only channels, the proposed hybrid array has the higher signal-to-noise ratio (SNR) and better parallel imaging performance. Sufficient electromagnetic decoupling and diverse RF magnetic field (B1) distributions of monopole channels and loop channels may contribute to this performance improvement. From experimental results, the hybrid monopole/loop array has low g-factor and excellent SNR at both periphery and center of the brain, which is valuable for human head imaging at ultrahigh fields.

中文翻译：

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用于 7 T 人体头部 MR 成像的混合单极/环形线圈阵列

单极线圈和环形线圈具有正交射频 (RF) 场，因此如果布置得当，它们本质上是电磁去耦的。在这项研究中，我们提出了一种混合单极/环技术，它可以结合环阵列和单极阵列的优点。为了研究这项技术，开发了一种包含四个单极子通道和四个环路通道的混合射频线圈阵列，用于 7 T 的人体头部磁共振 (MR) 成像。 体内 MR 成像和 g 因子结果使用仅单极子通道、环路-仅获取和评估混合阵列的通道和所有通道。与仅单极子和仅环通道相比，所提出的混合阵列具有更高的信噪比（SNR）和更好的并行成像性能。单极通道和环路通道的充分电磁去耦和多样化的射频磁场 (B1) 分布可能有助于这种性能改进。从实验结果来看，混合单极/环阵列在大脑的外围和中心都具有低 g 因子和出色的信噪比，这对于超高场的人体头部成像很有价值。