Enhanced detection of glutamate via transverse relaxation encoding with narrowband decoupling in the human brain.

IF 3 3区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Magnetic Resonance in Medicine Pub Date : 2025-01-20 DOI:10.1002/mrm.30431

Li An, Sungtak Hong, Tara Turon, Adriana Pavletic, Christopher S Johnson, John A Derbyshire, Jun Shen

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Abstract

Purpose: This study aims to improve the detection of glutamate (Glu) concentration and T₂ using an enhanced transverse relaxation encoding with narrowband decoupling (TREND) technique.

Methods: A new editing pulse was designed to simultaneously invert both Glu H3 spins (2.12 ppm and 2.05 ppm) while minimizing the excitation of Glu H4. Additionally, a frequency band was created to invert the lactate (Lac) H2 spin (4.10 ppm) while saturating the NAA aspartyl H2 spin (4.38 ppm). Numerical simulations compared Glu and Lac signals using the original and new editing pulses. In vivo experiments were conducted on healthy participants at 7 T to validate this enhanced TREND technique.

Results: Numerical simulations showed prominently enhanced Glu and Lac resonance signals with the new editing pulse. In vivo spectra showed a 47% ± 14% increase in Glu/Cr peak amplitude ratios with the new editing pulse. Using the enhanced TREND sequence, Glu/Cr concentration ratios in the anterior cingulate cortex were 1.03 ± 0.07 with Cramer-Rao lower bounds (CRLBs) of 1.1% ± 0.1%, and Glu T₂ values were 179 ± 18 ms with CRLBs of 1.2% ± 0.1%. The Lac/Cr concentration ratios in the same voxels were 0.05 ± 0.01 with CRLBs of 26% ± 14%, and Lac T₂ values were 196 ± 23 ms with CRLBs of 22% ± 15%.

Conclusion: The new editing pulse significantly enhanced the detection of Glu and enabled the detection of Lac using TREND for measuring both the concentration and T₂ of the markers of oxidative metabolism and glycolysis.

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通过窄带解耦的横向松弛编码增强对人脑谷氨酸的检测。

目的：利用窄带解耦增强横向弛豫编码（TREND）技术，改进谷氨酸（Glu）浓度和T2的检测。方法：设计一种新的编辑脉冲，同时反转Glu H3自旋（2.12 ppm和2.05 ppm），同时最小化Glu H4的激发。此外，创建了一个频段来反转乳酸（Lac） H2自旋（4.10 ppm），同时使NAA天冬氨酸H2自旋（4.38 ppm）饱和。数值模拟比较了使用原始和新的编辑脉冲的Glu和Lac信号。在7 T的健康参与者身上进行了体内实验，以验证这种增强的TREND技术。结果：数值模拟显示，新编辑脉冲显著增强了Glu和Lac共振信号。体内光谱显示，在新的编辑脉冲下，Glu/Cr峰值幅度比增加了47%±14%。增强趋势序列显示，前扣带皮层Glu/Cr浓度比值为1.03±0.07，crmer - rao下限（crlb）为1.1%±0.1%；Glu T2值为179±18 ms， crlb为1.2%±0.1%。同一体素中Lac/Cr浓度比为0.05±0.01，CRLBs为26%±14%；Lac T2值为196±23 ms， CRLBs为22%±15%。结论：新的编辑脉冲显著增强了Glu的检测，并使使用TREND检测Lac成为可能，可以同时测量氧化代谢和糖酵解标志物的浓度和T2。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Magnetic Resonance in Medicine 医学-核医学

CiteScore

6.70

自引率

24.20%

发文量

376

审稿时长

2-4 weeks

期刊介绍： Magnetic Resonance in Medicine (Magn Reson Med) is an international journal devoted to the publication of original investigations concerned with all aspects of the development and use of nuclear magnetic resonance and electron paramagnetic resonance techniques for medical applications. Reports of original investigations in the areas of mathematics, computing, engineering, physics, biophysics, chemistry, biochemistry, and physiology directly relevant to magnetic resonance will be accepted, as well as methodology-oriented clinical studies.