Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.
Magn Reson Med. 2022 Feb;87(2):589-596. doi: 10.1002/mrm.29008. Epub 2021 Sep 14.
To investigate the editing-pulse flip angle (FA) dependence of editing efficiency and ultimately to maximize the edited signal of commonly edited MR spectroscopy (MRS) signals, such as gamma-aminobutyric acid (GABA) and lactate.
Density-matrix simulations were performed for a range of spin systems to find the editing-pulse FA for maximal editing efficiency. Simulations were confirmed by phantom experiments and in vivo measurements in 10 healthy participants using a 3T Philips scanner. Four MEGA-PRESS in vivo measurements targeting GABA+ and lactate were performed, comparing the conventional editing-pulse FA (FA = 180°) to the optimal one suggested by simulations (FA = 210°).
Simulations and phantom experiments show that edited GABA and lactate signals are maximal at FA = 210°. Compared to conventional editing (FA = 180°), in vivo signals from GABA+ and lactate signals increase on average by 8.5% and 9.3%, respectively.
Increasing the FA of editing-pulses in the MEGA-PRESS experiment from 180° to 210° increases the edited signals from GABA+ and lactate by about 9% in vivo.
研究编辑脉冲翻转角（FA）对编辑效率的影响，最终最大化常见编辑磁共振波谱（MRS）信号（如γ-氨基丁酸（GABA）和乳酸）的编辑信号。
针对一系列自旋系统进行密度矩阵模拟，以找到最大编辑效率的编辑脉冲 FA。通过体模实验和 10 名健康参与者的体内测量在 3T 飞利浦扫描仪上进行了模拟验证。针对 GABA+和乳酸进行了四次 MEGA-PRESS 体内测量，将传统编辑脉冲 FA（FA=180°）与模拟建议的最佳 FA（FA=210°）进行比较。
模拟和体模实验表明，编辑后的 GABA 和乳酸信号在 FA=210°时达到最大值。与传统编辑（FA=180°）相比，GABA+和乳酸信号的体内信号平均增加了 8.5%和 9.3%。
在 MEGA-PRESS 实验中，将编辑脉冲的 FA 从 180°增加到 210°，可使 GABA+和乳酸的编辑信号在体内分别增加约 9%。
