对非耦合自旋的受激回波脉冲序列所产生的磁化强度的本征共振偏移依赖性的分析。

An analysis of the intrinsic resonance offset dependence of magnetization generated by stimulated echo pulse sequences for noncoupled spins.

作者信息

Ballon D, Garwood M, Koutcher J A

机构信息

Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.

出版信息

Magn Reson Imaging. 1991;9(4):569-75. doi: 10.1016/0730-725x(91)90044-m.

DOI:10.1016/0730-725x(91)90044-m

PMID:1779728

Abstract

It is demonstrated that the basic radiofrequency pulse train used to generate stimulated echoes (90x-tau TE-90x-tau TM-90x-tau TE-Acq.) is in general characterized by strong amplitude and phase modulations of the transverse magnetization as a function of the resonance offset. Two dephasing techniques which eliminate the modulations are investigated both theoretically and experimentally, and a simple formula is derived for calculating the relative modulation across a spectrum as a function of gradient strength and duration, echo delay, and spectral linewidth.

摘要

结果表明，用于产生受激回波的基本射频脉冲序列（90x - τ TE - 90x - τ TM - 90x - τ TE - Acq.）通常具有横向磁化强度随共振偏移而产生强烈幅度和相位调制的特征。从理论和实验两方面研究了两种消除调制的去相技术，并推导了一个简单公式，用于计算作为梯度强度、持续时间、回波延迟和谱线宽度函数的频谱上的相对调制。