Small-tip fast recovery imaging using non-slice-selective tailored tip-up pulses and radiofrequency-spoiling
Small-tip fast recovery imaging using non-slice-selective tailored tip-up pulses and radiofrequency-spoiling
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DOI：
10.1002/mrm.24289
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发表时间：
2013-03-01
影响因子：
3.3
通讯作者：
Noll, Douglas C.
中科院分区：
文献类型：
--
作者：
Nielsen, Jon-Fredrik;Yoon, Daehyun;Noll, Douglas C.
小尖端快速恢复（STFR）成像是一种新的稳态成像序列，是平衡稳态自由进动的潜在替代方案。在理想的成像条件下，STFR可以提供与平衡的稳态自由进动相当的信噪比和图像对比度，但没有由于共振偏移引起的信号变化。STFR依赖于定制的翻转或快速恢复射频脉冲，以在每个数据读出段之后将自旋与纵轴对齐。翻起脉冲的设计基于单独的非共振（B 0）图的采集。不幸的是，设计快速（几ms）切片或平板选择性射频脉冲，准确地定制激励模式的局部B 0不均匀性在整个成像体积仍然是一个具有挑战性的和未解决的问题。我们介绍了一种新的实现STFR成像的基础上，非切片选择性翻转脉冲，大大简化了射频脉冲的设计问题。使用射频破坏抑制切片外磁化路径。用这种技术获得的脑图像显示出极好的灰/白色物质对比度，并指出快速稳态T2/T1加权成像的可能性与脑脊液的内在抑制，通过平面的血管信号，和非共振伪影。在未来，我们预计STFR成像受益于并行激励硬件和高阶梯度匀场系统显着。Magn Reson Med，2013年。(c)2012 Wiley Periodicals，Inc.
Small-tip fast recovery (STFR) imaging is a new steady-state imaging sequence that is a potential alternative to balanced steady-state free precession. Under ideal imaging conditions, STFR may provide comparable signal-to-noise ratio and image contrast as balanced steady-state free precession, but without signal variations due to resonance offset. STFR relies on a tailored tip-up, or fast recovery, radiofrequency pulse to align the spins with the longitudinal axis after each data readout segment. The design of the tip-up pulse is based on the acquisition of a separate off-resonance (B0) map. Unfortunately, the design of fast (a few ms) slice- or slab-selective radiofrequency pulses that accurately tailor the excitation pattern to the local B0 inhomogeneity over the entire imaging volume remains a challenging and unsolved problem. We introduce a novel implementation of STFR imaging based on non-slice-selective tip-up pulses, which simplifies the radiofrequency pulse design problem significantly. Out-of-slice magnetization pathways are suppressed using radiofrequency-spoiling. Brain images obtained with this technique show excellent gray/white matter contrast, and point to the possibility of rapid steady-state T2/T1-weighted imaging with intrinsic suppression of cerebrospinal fluid, through-plane vessel signal, and off-resonance artifacts. In the future, we expect STFR imaging to benefit significantly from parallel excitation hardware and high-order gradient shim systems. Magn Reson Med, 2013. (c) 2012 Wiley Periodicals, Inc.