ON THE APPLICATION OF ULTRA-FAST RARE EXPERIMENTS
ON THE APPLICATION OF ULTRA-FAST RARE EXPERIMENTS
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DOI：
10.1002/mrm.1910270114
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发表时间：
1992-09-01
影响因子：
3.3
通讯作者：
LEIBFRITZ, D
中科院分区：
文献类型：
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作者：
NORRIS, DG;BORNERT, P;LEIBFRITZ, D
详细描述了RARE实验的超快速应用，特别强调了它在产生横向磁化的制备实验中的各种应用。描述了实验过程中影响磁化时间演变的因素，并对高斯重聚焦脉冲对切片剖面的影响进行了实验研究。讨论了用于制备实验的相位编码方案的选择，以及如果获得许多平均值，则使用各种相位编码方案来减少相位编码方向上的线展宽。给出了读梯度不平衡时回波群分解为两个分量的解释，并描述了这两个回波群相干相加所需的实验条件。提出了一种从采集窗口中删除这些组之一的替代序列。研究了序列对流动和运动的敏感性，并解释了在这种情况下信号的剧烈损失。本文介绍了这些方法在制备实验中的体内和体外应用，从而精确测量了T1、T2、扩散常数和磁化传递特性。描述了使用自旋和受激回波制备的变焦成像的实现，并给出了3Din活体自旋回波变焦图像。简单的幻影实验也证明了化学位移选择成像和光谱成像的可行性。
The ultra‐fast application of the RARE experiment is described in detail, with special emphasis on its multifarious applications with preparation experiments that produce transverse magnetization. The factors affecting the temporal evolution of the magnetization during the experiment are described, and the implications for the slice profile when using a Gaussian refocusing pulse are experimentally examined. The choice of phase‐encoding scheme for use with preparation experiments is discussed, as is the use of various phase‐encoding schemes to reduce line broadening in the phase‐encoding direction if a number of averages are acquired. An explanation for the decomposition of the echo are into two components if the read gradient is imbalanced is given, and the experimental conditions necessary for the coherent addition of these two echo groups are described. An alternative sequence that removes one of these groups from the acquisition window is proposed. The sensitivity of the sequence to flow and motion is investigated, and the drastic loss of signal in this situation explained. Thein vivoandin vitroapplication of preparation experiments leading to the accurate measurement of T1, T2, diffusion constant, and magnetization transfer characteristics is presented. The implementation of zoom‐imaging using spin‐ and stimulated‐echo preparation is described, and 3Din vivospin‐echo zoom images are presented. Simple phantom experiments demonstrating the feasibility of chemical‐shift selective and spectroscopic imaging are also given.