Terpstra Melissa, Ugurbil Kamil, Gruetter Rolf
Center for MR Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Magn Reson Med. 2002 May;47(5):1009-12. doi: 10.1002/mrm.10146.
Spectral editing of the GABA spin system is hampered by coediting of macromolecule (MM) coherences. To reduce contamination arising from MMs in spectra edited for GABA, the highest field strength currently available for human experimentation (7 Tesla) and MEGA-based editing were used. Despite judicious choice of experimental parameters, MM contamination was found to arise from field drifts. When the MM contribution was accounted for, [GABA] = 0.75 +/- 0.14 micromol/g (mean +/- SD, N = 16) relative to 8 micromol/g creatine (Cr), whereas without accounting for the MM signal [GABA*] = 0.88 +/- 0.23 micromol/g (mean +/- SD, N = 16). Incorporating the direct experimental assessment of MM contamination to the edited GABA signal substantially reduced the variance of the measurement, resulting in concentrations that were in excellent agreement with previous (13)C labeling experiments.
GABA自旋系统的光谱编辑受到大分子（MM）相干性的共编辑影响。为了减少在针对GABA编辑的光谱中MM产生的污染，使用了目前可用于人体实验的最高场强（7特斯拉）和基于MEGA的编辑方法。尽管对实验参数进行了明智的选择，但发现MM污染是由场漂移引起的。当考虑MM的贡献时，相对于8微摩尔/克肌酸（Cr），[GABA] = 0.75 +/- 0.14微摩尔/克（平均值 +/- 标准差，N = 16），而不考虑MM信号时，[GABA*] = 0.88 +/- 0.23微摩尔/克（平均值 +/- 标准差，N = 16）。将MM污染的直接实验评估纳入编辑后的GABA信号中，大大降低了测量的方差，得到的浓度与先前的（13）C标记实验结果非常一致。
