Spatially localized, one- and two-dimensional NMR spectroscopy and in vivo application to human muscle
Spatially localized, one- and two-dimensional NMR spectroscopy and in vivo application to human muscle
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DOI：
10.1006/jmrb.1996.0163
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发表时间：
1996-11-01
期刊：
影响因子：
--
通讯作者：
Boesch, C
中科院分区：
文献类型：
--
作者：
Kreis, R;Boesch, C
最近据报道，人体肌肉的局部 H-1 磁共振谱具有未分配的、方向相关的共振线。为了进行体内表征，将各种 NMR 技术与 3D 空间定位相结合：2D-J 光谱、零量子和塞曼阶滤波、双量子滤波、2D 恒定时间 COSY、偶极阶滤波和 2D 纵向阶分离光谱。描述了这些方法在全身 MR 系统上的成功实施及其在研究人类受试者中的应用。人们发现人体肌肉的 H-1 MR 谱具有残余偶极耦合和各向异性磁化率的特征，这使得共振频率、相位以及某些序列的信号强度与方向相关。其中两个未识别的共振明确地形成了两个等价质子的偶极双峰，中心位于 3.93 ppm。所有未知以及先前指定的 2.7 至 3.6 ppm 范围内的峰要么本身受到偶极耦合，要么与偶极耦合中涉及的代谢物的光谱贡献重叠。肌酸的甲基质子可能会受到残余偶极耦合的影响，因此形成偶极三重态，而不是先前假设的单重态。最后，X3（位于 3.5 ppm 处的另一个未识别峰）似乎是多重峰的一部分，其中心位于 3.3 ppm 处并与三甲基铵共振重叠。 (C) 1996 学术出版社
The localized H-1 MR spectrum of human muscle has recently been reported to feature unassigned, orientation-dependent resonance lines. For their characterization in vivo, various NMR techniques were combined with 3D spatial localization: 2D-J spectroscopy, zero-quantum- and Zeeman-order-filtering, double-quantum-filtering, 2D-constant-time COSY, dipolar-order filtering, and 2D-longitudinal-order separated spectroscopy. The successful implementation of these methods on a whole-body MR system and their application to study human subjects is described. H-1 MR spectra of human muscle were found to feature residual dipolar couplings and anisotropic susceptibilities which render resonance frequencies, phases, and-with some sequences-signal intensities orientation dependent. Two of the unidentified resonances unequivocally form a dipolar doublet of two equivalent protons, centered at 3.93 ppm. All unknown as well as previously assigned peaks in the range between 2.7 and 3.6 ppm are either subject to dipolar coupling themselves or overlap with spectral contributions of metabolites involved in dipolar coupling. The methyl protons of creatine are likely to be subject to residual dipolar coupling and do therefore form a dipolar triplet and not a singlet as previously assumed. Finally, X3, a further unidentified peak at 3.5 ppm, appears to be part of a multiplet with its center at 3.3 ppm and overlapping the trimethylammonium resonance. (C) 1996 Academic Press, Inc.