Optimized amplitude modulated multiband RF pulse design.
Optimized amplitude modulated multiband RF pulse design.
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DOI：
10.1002/mrm.26610
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发表时间：
2017-12
影响因子：
3.3
通讯作者：
Malik SJ
中科院分区：
文献类型：
--
作者：
Abo Seada S;Price AN;Hajnal JV;Malik SJ
多频带脉冲的特征是高度时间调制的波形。快速相位或频率调制可能对射频（RF）脉冲生成的性能要求极高，如果脉冲仅限于幅度调制（AM），则可能导致可以避免的误差。在这项工作中，三个现有的多频带脉冲设计技术进行修改，以产生AM波形。使用相位优化、时移和根翻转来设计多频带重聚焦脉冲。每种技术都被限制为通过利用其各自频域表示中的共轭对称性来产生AM脉冲。使用AM和无约束技术设计脉冲，用于一系列多波段因子（即，同时激发的切片数量）、时间带宽积和切片间隔。通过检查产生的有效脉冲持续时间来比较性能。进行了体模和体内实验进行验证。采集的数据证实，当无约束设计可能产生伪影时，AM脉冲可以产生精确的结果。AM脉冲的平均持续时间比无约束的版本长。在一系列参数的平均值下，AM脉冲的持续时间成本分别为相位优化、时移和根翻转的26%、38%和20%。可以产生幅度调制多频带脉冲，但脉冲持续时间增加相对较小。Magn Reson Med 78：2185-2193，2017。© 2017 The Authors Magnetic Resonance in Medicine出版由Wiley Periodicals，Inc.国际医学磁共振学会（International Society for Magnetic Resonance in Medicine）这是一个开放获取的条款下的知识共享署名许可证，允许使用，分发和复制在任何媒体上，只要原始作品是适当的引用。
Multiband pulses are characterized by highly temporally modulated waveforms. Rapid phase or frequency modulation can be extremely demanding on the performance of radiofrequency (RF) pulse generation, which can lead to errors that can be avoided if pulses are restricted to amplitude modulation (AM) only. In this work, three existing multiband pulse design techniques are modified to produce AM waveforms. Multiband refocusing pulses were designed using phase‐optimization, time‐shifting, and root‐flipping. Each technique was constrained to produce AM pulses by exploiting conjugate symmetry in their respective frequency domain representations. Pulses were designed using the AM and unconstrained techniques for a range of multiband factors (ie, number of simultaneously excited slices), time‐bandwidth products, and slice separations. Performance was compared by examining the resulting effective pulse durations. Phantom and in vivo experiments were conducted for validation. Acquired data confirmed that AM pulses can produce precise results when unconstrained designs may produce artifacts. The average duration of AM pulses is longer than the unconstrained versions. Averaged across a range of parameters, the duration cost for AM pulses was 26, 38, and 20% for phase‐optimizing, time‐shifting and root‐flipping, respectively. Amplitude modulation multiband pulses can be produced for a relatively small increase in pulse duration. Magn Reson Med 78:2185–2193, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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影响因子：
3.3
作者：
Sharma A;Lustig M;Grissom WA
通讯作者：
Grissom WA
影响因子：
3.3
作者：
Auerbach, Edward J.;Xu, Junqian;Yacoub, Essa;Moeller, Steen;Ugurbil, Kamil
通讯作者：
Ugurbil, Kamil
影响因子：
10.6
作者：
PAULY, J;LEROUX, P;MACOVSKI, A
通讯作者：
MACOVSKI, A
影响因子：
3.3
作者：
Grissom, William A.;Kerr, Adam B.;Stang, Pascal;Scott, Greig C.;Pauly, John M.
通讯作者：
Pauly, John M.
影响因子：
2.2
作者：
Feinberg, David A.;Setsompop, Kawin
通讯作者：
Setsompop, Kawin