Yan Xinqiang, Wei Long, Xue Rong, Zhang Xiaoliang
Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China ; Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049, China ; State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China ; Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049, China.
Appl Magn Reson. 2015 May 1;46(5):541-550. doi: 10.1007/s00723-015-0656-5.
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 4 monopole channels and 4 loop channels was developed for human head MR imaging at 7T. 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 higher SNR and better parallel imaging performance. Sufficient electromagnetic decoupling and diverse RF magnetic field (B) 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.
单极线圈和环形线圈具有正交的射频（RF）场，因此，如果布局得当，它们在电磁上本质上是解耦的。在本研究中，我们提出了一种混合单极/环形技术，该技术可以结合环形阵列和单极阵列的优点。为了研究该技术，开发了一种包含4个单极通道和4个环形通道的混合射频线圈阵列，用于7T人体头部磁共振成像。获取并评估了使用单极通道、环形通道以及混合阵列所有通道的体内磁共振成像和g因子结果。与仅使用单极通道和仅使用环形通道相比，所提出的混合阵列具有更高的信噪比和更好的并行成像性能。单极通道和环形通道充分的电磁解耦以及多样的射频磁场（B）分布可能有助于这种性能的提升。从实验结果来看，混合单极/环形阵列在脑外周和中心均具有低g因子和出色的信噪比，这对于超高场下的人体头部成像具有重要价值。
