Integrated parallel reception, excitation, and shimming (iPRES) with multiple shim loops per radio-frequency coil element for improved B0 shimming
Integrated parallel reception, excitation, and shimming (iPRES) with multiple shim loops per radio-frequency coil element for improved B0 shimming
复制标题
DOI：
10.1002/mrm.26267
复制
发表时间：
2017-05-01
影响因子：
3.3
通讯作者：
Song, Allen W.
中科院分区：
文献类型：
--
作者：
Darnell, Dean;Truong, Trong-Kha;Song, Allen W.
目的集成的并行接收、激励和匀场（iPRES）线圈阵列允许射频电流和直流电流在同一线圈中流动，从而能够使用单个线圈阵列实现激励/接收和局部B-0匀场。这项工作的目的是通过增加对比射频线圈元件更小的高阶局部B-0不均匀性进行匀场的能力来改善它们的匀场性能。方法提出了一种新颖的设计，其中每个射频/匀场线圈元件被分成多个直流回路，每个回路使用独立的直流电流，以增加可用于匀场的磁场的数量，同时保持线圈的信噪比。这种新设计被称为iPRES（N），其中N表示每个射频线圈元件的直流回路的数量。使用8通道体线圈阵列进行了概念验证体模和人体实验，以证明其优于原始iPRES（1）design.ResultsThe平均B-0均匀性在各种器官的匀场前和匀场后的iPRES（1）或iPRES（3）线圈阵列分别为0.24，0.11和0.05 ppm。结论iPRES（N）比iPRES（1）能更有效地校正局部B-0不均匀性，且无信噪比损失，图像质量显著改善。Magn Reson Med 77：2077-2086，2017。(c)2016年国际医学磁共振学会
PurposeIntegrated parallel reception, excitation, and shimming (iPRES) coil arrays allow radio-frequency currents and direct currents to flow in the same coils, which enables excitation/reception and localized B-0 shimming with a single coil array. The purpose of this work was to improve their shimming performance by adding the capability to shim higher-order local B-0 inhomogeneities that are smaller than the radio-frequency coil elements.MethodsA novel design was proposed in which each radio-frequency/shim coil element is divided into multiple direct current loops, each using an independent direct current current, to increase the number of magnetic fields available for shimming while maintaining the signal-to-noise ratio of the coil. This new design is termed iPRES(N), where N represents the number of direct current loops per radio-frequency coil element. Proof-of-concept phantom and human experiments were performed with an 8-channel body coil array to demonstrate its advantages over the original iPRES(1) design.ResultsThe average B-0 homogeneity in various organs before shimming and after shimming with the iPRES(1) or iPRES(3) coil arrays was 0.24, 0.11, and 0.05 ppm, respectively. iPRES(3) thus reduced the B-0 inhomogeneity by 53% and further reduced distortions in echo-planar images of the abdomen when compared with iPRES(1).ConclusioniPRES(N) can correct for localized B-0 inhomogeneities more effectively than iPRES(1) with no signal-to-noise ratio loss, resulting in a significant improvement in image quality. Magn Reson Med 77:2077-2086, 2017. (c) 2016 International Society for Magnetic Resonance in Medicine