HERMES: Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy
HERMES: Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy
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DOI：
10.1002/mrm.26233
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发表时间：
2016-07-01
影响因子：
3.3
通讯作者：
Edden, Richard A. E.
中科院分区：
文献类型：
--
作者：
Chan, Kimberly L.;Puts, Nicolaas A. J.;Edden, Richard A. E.
目的：研究一种新颖的 Hadamard 编码光谱编辑方案，并评估其在 3 Tesla 下同时定量 N-乙酰天冬氨酸 (NAA) 和 N-乙酰天冬氨酰谷氨酸 (NAAG) 的性能。 方法：根据 Hadamard 编码方案应用的编辑脉冲可以同时采集多种代谢物。该方法称为 HERMES（MEGA 编辑光谱的哈达玛编码和重建），经过优化，可使用密度矩阵模拟同时检测 NAA 和 NAAG，并在 3T 体模中进行验证。体内数据是在 12 名正常受试者的半卵圆中心获得的。 NAA:NAAG浓度比是通过使用模拟基函数对体内数据进行建模来确定的。还对检测到的 NAA/NAAG 区域内具有信号的潜在共编辑分子进行了模拟。结果：模拟和模型实验表明，NAA 和 NAAG 信号出色地分离到预期光谱中，且串扰最小。多重模式显示模拟与模型和体内数据之间具有良好的一致性。体内测量表明，NAA 和 NAAG 光谱的相对峰强度与 NAA: NAAG 浓度比 4.22:1 一致，与文献吻合良好。模拟表明在检测区域附近存在天冬氨酸和谷胱甘肽的一些共编辑（编辑效率：对于 NAAG 重建分别为 4.5% 和 78.2%，对于 NAA 重建分别为 5.1% 和 19.5%）。结论：使用 HERMES 在 3T 下可以同时和可分离地检测两种重叠的代谢物。 (C) 2016 年 Wiley 期刊公司。
Purpose: To investigate a novel Hadamard-encoded spectral editing scheme and evaluate its performance in simultaneously quantifying N-acetyl aspartate (NAA) and N-acetyl aspartyl glutamate (NAAG) at 3 Tesla.Methods: Editing pulses applied according to a Hadamard encoding scheme allow the simultaneous acquisition of multiple metabolites. The method, called HERMES (Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy), was optimized to detect NAA and NAAG simultaneously using density-matrix simulations and validated in phantoms at 3T. In vivo data were acquired in the centrum semiovale of 12 normal subjects. The NAA: NAAG concentration ratio was determined by modeling in vivo data using simulated basis functions. Simulations were also performed for potentially coedited molecules with signals within the detected NAA/NAAG region.Results: Simulations and phantom experiments show excellent segregation of NAA and NAAG signals into the intended spectra, with minimal crosstalk. Multiplet patterns show good agreement between simulations and phantom and in vivo data. In vivo measurements show that the relative peak intensities of the NAA and NAAG spectra are consistent with a NAA: NAAG concentration ratio of 4.22:1 in good agreement with literature. Simulations indicate some coediting of aspartate and glutathione near the detected region (editing efficiency: 4.5% and 78.2%, respectively, for the NAAG reconstruction and 5.1% and 19.5%, respectively, for the NAA reconstruction).Conclusion: The simultaneous and separable detection of two otherwise overlapping metabolites using HERMES is possible at 3T. (C) 2016 Wiley Periodicals, Inc.