Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
J Magn Reson. 2013 Mar;228:37-44. doi: 10.1016/j.jmr.2012.12.021. Epub 2013 Jan 11.
T(2)(∗) weighted fMRI at high and ultra high field (UHF) is often hampered by susceptibility-induced, through-plane, signal loss. Three-dimensional tailored RF (3DTRF) pulses have been shown to be an effective approach for mitigating through-plane signal loss at UHF. However, the required RF pulse lengths are too long for practical applications. Recently, parallel transmission (PTX) has emerged as a very effective means for shortening the RF pulse duration for 3DTRF without sacrificing the excitation performance. In this article, we demonstrate a RF pulse design strategy for 3DTRF based on the use of multi-slice PTX 3DTRF to simultaneously and precisely recover signal with whole-brain coverage. Phantom and human experiments are used to demonstrate the effectiveness and robustness of the proposed method on three subjects using an eight-channel whole body parallel transmission system.
T(2)(∗)加权 fMRI 在高场和超高场（UHF）中常受到磁化率诱导的、沿层面的信号丢失的影响。三维定制射频（3DTRF）脉冲已被证明是减轻 UHF 中沿层面信号丢失的有效方法。然而，对于实际应用来说，所需的射频脉冲长度太长。最近，并行传输（PTX）已成为一种非常有效的手段，可以在不牺牲激发性能的情况下缩短 3DTRF 的射频脉冲持续时间。在本文中，我们展示了一种基于使用多层面并行传输 3DTRF 的射频脉冲设计策略，以同时精确地恢复具有全脑覆盖的信号。通过使用八通道全身并行传输系统，在三个对象上的体模和人体实验证明了所提出的方法的有效性和鲁棒性。
