DANTE-prepared pulse trains: A novel approach to motion-sensitized and motion-suppressed quantitative magnetic resonance imaging
DANTE-prepared pulse trains: A novel approach to motion-sensitized and motion-suppressed quantitative magnetic resonance imaging
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DOI：
10.1002/mrm.24142
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发表时间：
2012-11-01
影响因子：
3.3
通讯作者：
Jezzard, Peter
中科院分区：
文献类型：
--
作者：
Li, Linqing;Miller, Karla L.;Jezzard, Peter
延迟和章动交替用于定制激励(Dante)脉冲串被认为是傅里叶变换核磁共振中的频率选择性激发方法，并在磁共振成像中用于空间标记。在这项研究中，非选择性但丁脉冲串与梯度脉冲和短重复时间相结合用作运动敏感准备模块。我们发现，虽然静态组织的纵向磁化强度基本保持不变，但流动的自旋由于沿施加的梯度流动引起的破坏效应而未能建立横向稳定状态，因而在很大程度上(或完全)被衰减。流动自旋的衰减对自旋速度不敏感(在低阈值以上)，可以用一个简单的T1纵向磁化衰减模型近似量化。推导了瞬态期和稳态期应用但丁模时运动自旋和静态自旋的相关解析方程。通过将解析解和Bloch方程的数值模拟与模体和活体实验观测结果进行比较，验证了方程的有效性。基于这一对比机理，提出了但丁制剂在黑血管成像中的应用。一个Dante黑色血液成像模块的简单演示表明，它提供出色的血液信号抑制和静态组织信号保存。Magn Reson Med，2012。(C)2012年威利期刊公司。
Delay alternating with nutation for tailored excitation (DANTE) pulse trains are well appreciated as frequency-selective excitation methods in Fourier transform NMR and for spatial tagging in MRI. In this study, nonselective DANTE pulse trains are used in combination with gradient pulses and short repetition times as motion-sensitive preparation modules. We show that while the longitudinal magnetization of static tissue is mostly preserved, flowing spins are largely (or fully) attenuated as they fail to establish transverse steady state due to a spoiling effect caused by flow along the applied gradient. The attenuation of flowing spins is effectively insensitive to spin velocity (above a low threshold) and can be approximately quantified with a simple T1 longitudinal magnetization decay model. The relevant analytical equations for moving spins and static spins during DANTE module application are derived for both transient and steady state epochs. The equations are validated by comparing analytical solutions and numerical Bloch equation simulations against experimental observations in phantoms and in vivo. Based on this contrast mechanism, the application of the DANTE preparation to black blood vessel imaging is proposed. A simple demonstration of DANTE black blood imaging modules shows that it provides excellent blood signal suppression and static tissue signal preservation. Magn Reson Med, 2012. (c) 2012 Wiley Periodicals, Inc.