Vernickel P, Röschmann P, Findeklee C, Lüdeke K-M, Leussler Ch, Overweg J, Katscher U, Grässlin I, Schünemann K
Philips Research Europe, Hamburg, Germany.
Magn Reson Med. 2007 Aug;58(2):381-9. doi: 10.1002/mrm.21294.
Multichannel transmit magnetic resonance imaging (MR) systems have the potential to compensate for signal-intensity variations occurring at higher field strengths due to wave propagation effects in tissue. Methods such as RF shimming and local excitation in combination with parallel transmission can be applied to compensate for these effects. Moreover, parallel transmission can be applied to ease the excitation of arbitrarily shaped magnetization patterns. The implementation of these methods adds new requirements in terms of MRI hardware. This article describes the design of a decoupled eight-element transmit/receive body coil for 3T. The setup of the coil is explained, starting with standard single-channel resonators. Special focus is placed on the decoupling of the elements to obtain independent RF resonators. After a brief discussion of the underlying theory, the properties and limitations of the coil are outlined. Finally, the functionality and capabilities of the coil are demonstrated using RF measurements as well as MRI sequences.
多通道发射磁共振成像(MR)系统有潜力补偿由于组织中的波传播效应而在较高场强下出现的信号强度变化。诸如射频匀场和结合并行传输的局部激发等方法可用于补偿这些效应。此外,并行传输可用于简化任意形状磁化模式的激发。这些方法的实施对MRI硬件提出了新的要求。本文描述了一种用于3T的解耦八元件发射/接收体线圈的设计。从标准单通道谐振器开始,解释了线圈的设置。特别关注元件的解耦以获得独立的射频谐振器。在简要讨论了基础理论之后,概述了线圈的特性和局限性。最后,使用射频测量以及MRI序列展示了线圈的功能和能力。