FREQUENCY-MODULATED RADIOFREQUENCY PULSES IN SPIN-ECHO AND STIMULATED-ECHO EXPERIMENTS
FREQUENCY-MODULATED RADIOFREQUENCY PULSES IN SPIN-ECHO AND STIMULATED-ECHO EXPERIMENTS
复制标题
DOI：
10.1002/mrm.1910040205
复制
发表时间：
1987-02-01
影响因子：
3.3
通讯作者：
KUNZ, D
中科院分区：
文献类型：
--
作者：
KUNZ, D
基于线性扫频的调频射频脉冲在自旋回波和受激回波序列中进行了实验研究。事实证明，这些FM脉冲生成垂直于所选切片的二次相位，并且如果适当地选择扫描速度和梯度，则自旋回波或受激回波序列中的FM脉冲的二次相位可以相互补偿。对于一个完整的重新定相，一个公式，并支持测量切片轮廓。获得了矩形度良好的切片轮廓。最后，它表明，与这种技术的图像可以得到使用脉冲的带宽增加和峰值功率降低相比，AM的情况。
Frequency-modulated rf pulses based on a linear frequency sweep are studied experimentally in spin-echo and stimulated-echo sequences. It turns out that these FM pulses generate a quadratic phase perpendicular to the selected slice and that the quadratic phases of the FM pulses in a spin-echo or stimulated-echo sequence may compensate each other if sweep velocity and gradients are suitably chosen. For a complete rephasing, a formula is given and supported by measured slice profiles. Slice profiles of excellent rectangularity are obtained. Finally, it is shown that with this technique images can be obtained using pulses of increased bandwidth and reduced peak power compared with the AM situation.