Department of Psychiatry, University of Oxford, Oxford, UK.
NMR Biomed. 2011 Dec;24(10):1277-85. doi: 10.1002/nbm.1688. Epub 2011 Mar 8.
One of the most commonly used methods for in vivo MRS detection of γ-aminobutyric acid (GABA) is the MEGA-point-resolved spectroscopy (MEGA-PRESS) technique. However, accurate quantification of GABA using MEGA-PRESS is complicated by spectral co-editing of macromolecular resonances. In this article, a new pulse sequence is presented which enables GABA editing at 3T with the removal of macromolecule contamination. This sequence combines the conventional MEGA editing scheme with the SPECIAL localisation technique, and is therefore named MEGA-SPECIAL. Simulations and phantom experiments indicate that this new approach provides improved GABA editing efficiency relative to MEGA-PRESS, and in vivo results demonstrate effective removal of macromolecule contamination. In a study of the occipital lobe of five healthy volunteers, the macromolecule-corrected GABA/creatine ratio was found to be 0.093 ± 0.007 (mean ± standard deviation), whereas prior to macromolecule correction, the ratio was found to be 0.173 ± 0.013.
一种最常用于体内 γ-氨基丁酸（GABA）MRS 检测的方法是 MEGA 点分辨波谱（MEGA-PRESS）技术。然而，由于大分子共振的谱峰共编辑，使用 MEGA-PRESS 对 GABA 进行准确定量较为复杂。在本文中，提出了一种新的脉冲序列，该序列可在 3T 下实现 GABA 编辑，并去除大分子污染。该序列将常规的 MEGA 编辑方案与 SPECIAL 定位技术相结合，因此命名为 MEGA-SPECIAL。模拟和仿体实验表明，与 MEGA-PRESS 相比，这种新方法提供了更高的 GABA 编辑效率，并且体内结果表明可以有效去除大分子污染。在对五名健康志愿者的枕叶进行的研究中，发现经大分子校正后的 GABA/肌酸比为 0.093±0.007（平均值±标准差），而在进行大分子校正之前，该比值为 0.173±0.013。
