Russell H. Morgan Department of Radiology and Radiological Science, The 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. 2018 Aug;80(2):474-479. doi: 10.1002/mrm.27044. Epub 2017 Dec 28.
To demonstrate simultaneous editing of the two most commonly edited and overlapping signals, γ-aminobutyric acid (GABA), and glutathione (GSH), with Hadamard encoding and reconstruction of MEGA-edited spectroscopy (HERMES) using sLASER localization at 7T.
Density matrix simulations of HERMES at 7T were carried out and compared with phantom experiments. Additional phantom experiments were performed to characterize the echo time (TE) -dependent modulation of GABA- and GSH-edited HERMES spectra at TE of 80-160 ms. In vivo experiments were performed in 10 healthy volunteers, comparing HERMES (11 min) to sequentially acquired MEGA-sLASER detection of GABA and GSH (2 × 11 min).
Simulations of HERMES show GABA- and GSH-edited spectra with negligible levels of crosstalk, and give modest agreement with phantom spectra. The TE series of GABA- and GSH-edited HERMES spectra modulate as a result of T relaxation and coupling evolution, with GABA showing a stronger TE-dependence. In vivo HERMES experiments show well-edited GABA and GSH signals. Measured concentrations are not statistically different between HERMES and MEGA-sLASER for GABA (1. 051 ± 0.254 i.u. and 1.053 ± 0.248 i.u; P > 0.985) or GSH (0.300 ± 0.091 i.u. and 0.302 ± 0.093 i.u; P > 0.940).
Simulated, phantom and in vivo measurements of HERMES show excellent segregation of GABA- and GSH-edited signals, and excellent agreement with separately acquired MEGA-sLASER data. HERMES allows two-fold acceleration of editing while maintaining spectral quality compared with sequentially acquired MEGA-sLASER measurements. Magn Reson Med 80:474-479, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
展示使用 7T 时基于 sLASER 定位的 Hadamard 编码和重建的 MEGA-编辑光谱（HERMES）对γ-氨基丁酸（GABA）和谷胱甘肽（GSH）这两个最常编辑和重叠信号的同时编辑。
在 7T 时对 HERMES 进行密度矩阵模拟，并与体模实验进行比较。进行了额外的体模实验，以表征 GABA 和 GSH 编辑的 HERMES 光谱在 80-160ms 的回波时间（TE）依赖性调制。在 10 名健康志愿者中进行了体内实验，将 HERMES（11min）与 GABA 和 GSH 的顺序采集 MEGA-sLASER 检测（2×11min）进行了比较。
HERMES 的模拟显示 GABA 和 GSH 编辑谱具有可忽略的串扰水平，并与体模谱有适度的一致性。 GABA 和 GSH 编辑的 HERMES 光谱的 TE 系列由于 T1 弛豫和偶联演化而发生调制，其中 GABA 显示出更强的 TE 依赖性。体内 HERMES 实验显示出编辑良好的 GABA 和 GSH 信号。对于 GABA（1.051±0.254i.u.和 1.053±0.248i.u；P>0.985）或 GSH（0.300±0.091i.u.和 0.302±0.093i.u；P>0.940），HERMES 测量的浓度与 MEGA-sLASER 之间没有统计学差异。
HERMES 的模拟、体模和体内测量均显示出 GABA 和 GSH 编辑信号的出色分离，并与单独采集的 MEGA-sLASER 数据具有极好的一致性。与顺序采集的 MEGA-sLASER 测量相比，HERMES 允许在保持光谱质量的同时将编辑速度提高两倍。磁共振医学 80：474-479，2018。©2017 国际磁共振学会。
