使用加速三维锁相环序列进行翻转角映射。
Flip angle mapping with the accelerated 3D look-locker sequence.
作者信息
Wade Trevor, McKenzie Charles A, Rutt Brian K
机构信息
Department of Medical Biophysics, The University of Western Ontario, London, Canada.
出版信息
Magn Reson Med. 2014 Feb;71(2):591-8. doi: 10.1002/mrm.24697.
PURPOSE
A new approach to mapping the flip angle quickly and efficiently in 3D based on the Look-Locker technique is presented.
METHODS
We modified the accelerated 3D Look-Locker T1 measurement technique to allow rapid measurement of flip angle. By removing the inversion pulses and interleaving two radio frequency pulses with different amplitude, it is possible to fit directly for the true flip angle using a reduced number of parameters. This technique, non-inverted Double Angle Look-Locker, allows quick and efficient mapping of the flip angle in 3D.
RESULTS
non-inverted Double Angle Look-Locker is validated in vitro against the actual flip angle imaging technique for a range of flip angles and T1 values. Flip angle maps produced with non-inverted Double Angle Look-Locker can be acquired in approximately 1 min, and are accurate to within 10% of the actual flip angle imaging measurement. It is shown to accurately measure the excited slab profile of several different pulses. An application to correcting in vivo DESPOT T1 data is presented.
CONCLUSION
The presented technique is a rapid method for mapping flip angles across a 3D volume, capable of producing a flip angle map in approximately 1 min.
目的
提出一种基于Look-Locker技术在三维空间中快速高效地绘制翻转角的新方法。
方法
我们对加速三维Look-Locker T1测量技术进行了改进，以实现对翻转角的快速测量。通过去除反转脉冲并交错两个不同幅度的射频脉冲，可以使用较少的参数直接拟合真实的翻转角。这种技术，即非反转双角度Look-Locker，能够在三维空间中快速高效地绘制翻转角。
结果
非反转双角度Look-Locker在体外针对一系列翻转角和T1值与实际翻转角成像技术进行了验证。使用非反转双角度Look-Locker生成的翻转角图大约可在1分钟内获取，并且与实际翻转角成像测量的误差在10%以内。结果表明它能够准确测量几种不同脉冲的激发层轮廓。还展示了其在体内校正DESPOT T1数据方面的应用。
结论
所提出的技术是一种在三维体积内绘制翻转角的快速方法，能够在大约1分钟内生成翻转角图。
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