A Novel Phase and Frequency Navigator for Proton Magnetic Resonance Spectroscopy Using Water-Suppression Cycling
A Novel Phase and Frequency Navigator for Proton Magnetic Resonance Spectroscopy Using Water-Suppression Cycling
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DOI：
10.1002/mrm.22582
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Li, Jikun
中科院分区：
文献类型：
--
作者：
Ernst, Thomas;Li, Jikun
磁共振波谱对运动敏感，部分原因是运动引起的相位和频率变化导致非相干平均。对于体内质子磁共振光谱，未抑制或抑制不足的水信号可用于恢复相干平均;然而，这种方法会导致基线失真，因为水峰很大。因此，开发了一种新的水抑制循环方案，该方案在正和负残余水信号之间交替。使用残余水信号，该方法允许对单个自由感应衰减进行逐炮相位和频率校正，并恢复由于非相干平均而导致的信号损失，但几乎完全消除残余水。它表明，残留的水信号可以被用来恢复代谢物峰在脑谱从受试者进行故意头部运动。在受试者运动期间校正相位和频率波动的能力对于与自适应运动校正方法一起使用是至关重要的，所述自适应运动校正方法确保在头部运动期间正确的体素定位。Magn Reson Med 65：13-17，2011年。(c)2010 Wiley-Liss，Inc.
Magnetic resonance spectroscopy is sensitive to movements, in part, because of motion-induced phase and frequency variations that lead to incoherent averaging. For in vivo proton magnetic resonance spectroscopy, the unsuppressed or under-suppressed water signal can be used to restore coherent averaging; however, this approach results in baseline distortions due to the large water peak. Therefore, a novel water-suppression cycling scheme was developed that alternates between positive and negative residual water signal. Using the residual water signal, the method allows for shot-to-shot phase and frequency correction of individual free induction decays and restoration of signal losses due to incoherent averaging, yet near-complete elimination of residual water. It is demonstrated that the residual water signal can be used to restore metabolite peaks in a brain spectrum from a subject who performed intentional head movements. The ability to correct phase and frequency fluctuations during subject motion is vital for use with adaptive motion correction approaches that ensure proper voxel positioning during head movements. Magn Reson Med 65:13-17, 2011. (c) 2010 Wiley-Liss, Inc.