Temperature dependence of 1H NMR chemical shifts and its influence on estimated metabolite concentrations
Temperature dependence of 1H NMR chemical shifts and its influence on estimated metabolite concentrations
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DOI：
10.1007/s10334-017-0642-z
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发表时间：
2017-12-01
影响因子：
2.3
通讯作者：
Dreher, Wolfgang
中科院分区：
文献类型：
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作者：
Wermter, Felizitas C.;Mitschke, Nico;Dreher, Wolfgang
研究了通过局部H-1 MRS测量的重要脑代谢物的温度依赖性化学位移，以测试使用关于化学位移的不正确先验知识如何损害代谢物浓度的定量。化学位移差的温度依赖性由线性模型拟合。模拟不同温度下的光谱，并通过AQSES程序（jMRUI 5.2）使用化学位移值为37 A ℃的模型函数进行分析。确定化学位移差异的温度依赖性存在较大差异，最大斜率约为+/- 7.5 x 10（-4）ppm/K。对于32-40 A ℃，除了Cr和PCr之外，使用不正确的化学位移仅导致轻微的定量误差。对于1-10 A ° C，如果忽略化学位移的温度依赖性，则会出现相当大的定量误差。如果不在37 A ° C下进行H-1 MRS测量，则应考虑化学位移的温度依赖性，以避免系统的定量误差，特别是对于在较低温度下对动物模型的测量。
Temperature dependent chemical shifts of important brain metabolites measured by localised H-1 MRS were investigated to test how the use of incorrect prior knowledge on chemical shifts impairs the quantification of metabolite concentrations.Phantom measurements on solutions containing 11 metabolites were performed on a 7 T scanner between 1 and 43 A degrees C. The temperature dependence of the chemical shift differences was fitted by a linear model. Spectra were simulated for different temperatures and analysed by the AQSES program (jMRUI 5.2) using model functions with chemical shift values for 37 A degrees C.Large differences in the temperature dependence of the chemical shift differences were determined with a maximum slope of about +/- 7.5 x 10(-4) ppm/K. For 32-40 A degrees C, only minor quantification errors resulted from using incorrect chemical shifts, with the exception of Cr and PCr. For 1-10 A degrees C considerable quantification errors occurred if the temperature dependence of the chemical shifts was neglected.If H-1 MRS measurements are not performed at 37 A degrees C, for which the published chemical shift values have been determined, the temperature dependence of chemical shifts should be considered to avoid systematic quantification errors, particularly for measurements on animal models at lower temperatures.