Parallel transmission RF pulse design for eddy current correction at ultra high field.
Parallel transmission RF pulse design for eddy current correction at ultra high field.
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DOI：
10.1016/j.jmr.2012.03.017
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发表时间：
2012-08
影响因子：
2.2
通讯作者：
Boada, Fernando
中科院分区：
文献类型：
--
作者：
Zheng, Hai;Zhao, Tiejun;Qian, Yongxian;Ibrahim, Tamer;Boada, Fernando
多维空间选择性射频脉冲已用于 MRI 应用，例如 B1 和 B0 不均匀性缓解。然而，长脉冲持续时间限制了它们的实际应用。最近的理论和实验研究表明，并行传输技术可以在不牺牲激励模式质量的情况下有效缩短脉冲持续时间。尽管如此，加速脉冲的并行传输可能会受到硬件和/或系统缺陷的严重阻碍。这些缺陷之一是涡流场的影响。在本文中，我们首先展示了涡流场对激励模式的影响，然后报告了射频脉冲设计方法来校正由射频线圈和梯度系统引起的涡流场。 7T 人体八通道发射系统的实验结果表明，使用涡流校正后，激励模式得到了显着改善。此外，所提出的基于模型的校正方法不仅展示了与轨迹测量方法相当的激励模式，而且显着提高了时间效率。
Multidimensional spatially selective RF pulses have been used in MRI applications such as B1 and B0 inhomogeneities mitigation. However, the long pulse duration has limited their practical applications. Recently, theoretical and experimental studies have shown that parallel transmission technique can effectively shorten pulse duration without sacrificing the quality of the excitation pattern. Nonetheless, parallel transmission with accelerated pulses can be severely impeded by hardware and/or system imperfections. One of such imperfections is the effect of the eddy current field. In this paper, we first show the effects of the eddy current field on the excitation pattern and then report RF pulse design method to correct eddy current fields caused by the RF coil and gradient system. Experimental results on a 7T human eight-channel transmit system show substantial improvements on excitation patterns with the use of eddy current correction. Moreover, the proposed model-based correction method not only demonstrates the comparable excitation pattern as the trajectory measurement method, but also significantly improves time efficiency.
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影响因子：
3.3
作者：
Setsompop, Kawin;Alagappan, Vijayanand;Gagoski, Borjan;Witzel, Thomas;Polimeni, Jonathan;Potthast, Andreas;Hebrank, Franz;Fontius, Ulrich;Schmitt, Franz;Wald, Lawrence L.;Adalsteinsson, Elfar
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3.3
作者：
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通讯作者：
PETERS, T