Recent advances in J-difference-edited proton magnetic resonance spectroscopy (1H MRS) data acquisition and processing have led to the development of Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy (HERMES) techniques, which enable the simultaneous measurement of ɣ-aminobutyric acid (GABA), the primary inhibitory amino acid neurotransmitter in the central nervous system, and of glutathione (GSH), the most abundant antioxidant in living tissue, at the commonly available magnetic field strength of 3 T. However, the reproducibility of brain levels of GABA and GSH measured across multiple scans in human subjects using HERMES remains to be established. In the present study, twelve healthy volunteers completed two consecutive HERMES scans of the dorsal anterior cingulate cortex (dACC) to assess the test-retest reproducibility of the technique for GABA and GSH measurements at TE = 80 ms. Eleven of the twelve participants additionally completed two consecutive MEGA-PRESS scans at TE = 120 ms, with editing pulses configured for GSH acquisition, to compare the reliability of GSH in the same voxel measured using the standard MEGA-PRESS at TE = 120 ms. The primary findings of study were that, 1) the coefficient of variation (CV) of measuring GABA with HERMES was 16.7%, which is in agreement with the reliability we previously reported for measuring GABA using MEGA-PRESS; and 2) the reliability of measuring GSH with MEGA-PRESS at TE = 120 ms was more than twice as high as that for measuring the antioxidant with HERMES at TE = 80 ms (CV = 7.3% vs. 19.0% respectively). These findings suggest that HERMES and MEGA-PRESS offer similar reliabilities for measuring GABA, while MEGA-PRESS at TE = 120 ms is more reliable for measuring GSH relative to HERMES at TE = 80 ms.

中文翻译：

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评价在健康的志愿者中，J差异编辑序列在不同回波时间下获得的1H-MRS GABA和GSH水平的可重复性。

J差动编辑质子磁共振波谱（1H MRS）数据采集和处理的最新进展导致了Hadamard编码和MEGA编辑波谱（HERMES）技术的重建，该技术可同时测量ɣ-氨基丁酸（GABA）是中枢神经系统中的主要抑制性氨基酸神经递质，而谷胱甘肽（GSH）是活组织中最丰富的抗氧化剂，其磁场强度通常为3T。使用HERMES在人类受试者的多次扫描中测得的GABA和GSH仍有待确定。在目前的研究中，十二名健康志愿者完成了连续两次对背扣带回前皮质（dACC）的HERMES扫描，以评估该技术在TE = 80 ms时对GABA和GSH测量的重测重现性。12名参与者中的11名还另外在TE = 120 ms处完成了两次连续的MEGA-PRESS扫描，并配置了用于GSH采集的编辑脉冲，以比较在TE = 120 ms时使用标准MEGA-PRESS测量的同一体素中GSH的可靠性。研究的主要发现是：1）用HERMES测量GABA的变异系数（CV）为16.7％，这与我们先前报道的使用MEGA-PRESS测量GABA的可靠性相符；2）在TE = 120 ms时用MEGA-PRESS测量GSH的可靠性是在TE = 80 ms时用HERMES测量抗氧化剂的可靠性的两倍高（分别为CV = 7.3％和19.0％）。这些发现表明，HERMES和MEGA-PRESS在测量GABA方面具有相似的可靠性，而TE = 120 ms的MEGA-PRESS相对于TE = 80 ms的HERMES测量GSH更可靠。