Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Magn Reson Med. 2018 Mar;79(3):1429-1438. doi: 10.1002/mrm.26801. Epub 2017 Jun 27.
Because the resonance frequency of water-fat intermolecular zero-quantum coherences (iZQCs) reflects the water-fat frequency separation at the microscopic scale, these frequencies have been proposed and used as a mean to obtain more accurate temperature information. The purpose of this work was to investigate the dependence of the water-fat iZQC resonance frequency on sample microstructure and on the specific choice of the correlation distance.
The effect of water-fat susceptibility gradients on the water-methylene iZQC resonance frequency was first computed and then measured for different water-fat emulsions and for a mixture of porcine muscle and fat. Similar measurements were also performed for mixed heteronuclear spin systems.
A strong dependence of the iZQC resonance frequency on the sample microstructure and on the specific choice of the correlation distance was found for spin systems like water and fat that do not mix, but not for spin systems that mix at the molecular level.
Because water and fat spins do not mix at the molecular level, the water-fat iZQC resonance frequency and its temperature coefficient are not only affected by sample microstructure but also by the specific choice of the correlation distance. Magn Reson Med 79:1429-1438, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
由于水-脂分子间零量子相干（iZQC）的共振频率反映了微观尺度下水-脂的频率分离，因此这些频率已被提出并用于获得更准确的温度信息。本研究的目的是探讨水-脂 iZQC 共振频率对样品微观结构以及相关距离的具体选择的依赖性。
首先计算了水-脂磁化率梯度对水-亚甲基 iZQC 共振频率的影响，然后对不同的水-脂乳液以及猪肌肉和脂肪混合物进行了测量。还对混合异核自旋系统进行了类似的测量。
对于像水和脂肪这样不混合的自旋系统，发现 iZQC 共振频率强烈依赖于样品微观结构以及相关距离的具体选择，但对于在分子水平上混合的自旋系统则不然。
由于水和脂肪的自旋在分子水平上不混合，因此水-脂 iZQC 共振频率及其温度系数不仅受样品微观结构的影响，还受相关距离的具体选择的影响。磁共振医学 79：1429-1438，2018。©2017 国际磁共振学会。
