Department of Physics, Fujian Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surface, Xiamen University, Xiamen 361005, China.
Phys Chem Chem Phys. 2010 Jun 21;12(23):6014-20. doi: 10.1039/b920180g. Epub 2010 Apr 28.
Intermolecular zero-quantum coherences (iZQCs) have been utilized to achieve high-resolution nuclear magnetic resonance (NMR) proton spectra under inhomogeneous and/or unstable fields. In this paper, we demonstrated that despite the insensitivity of iZQCs to B(0) variations, the influence of unstable fields on the observable single-quantum coherence signals causes strong t(1) noises in the high-resolution iZQC spectra. Short-time acquisition (STA) and phase spectrum schemes were proposed for noise suppression in in vivo iZQC magnetic resonance spectroscopy (MRS) under temporal B(0) variations. The feasibility of these schemes were verified by localized spectroscopic studies under B(0) variations generated by the Z0 coil current oscillations and by voxel position variations in the presence of field gradients, which simulate the field conditions of MRS in the presence of physiological motions. The phase scheme not only improves the signal-to-noise ratio but also further reduces the linewidth by half.
尽管分子间零量子相干（iZQCs）对 B0 变化不敏感，但不稳定场对可观测单量子相干信号的影响会导致高分辨率 iZQC 谱中出现强 t1 噪声。本文提出了在存在时变 B0 的情况下，采用短时间采集（STA）和相位谱方案来抑制体内 iZQC 磁共振波谱（MRS）中的噪声。通过对 Z0 线圈电流振荡引起的 B0 变化和存在磁场梯度时的体素位置变化下的局域光谱研究，验证了这些方案的可行性，这些变化模拟了生理运动存在时 MRS 的磁场条件。相位谱不仅提高了信噪比，还将线宽进一步减半。
