In vitro study of endogenous CEST agents at 3 T and 7 T.
In vitro study of endogenous CEST agents at 3 T and 7 T.
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DOI：
10.1002/cmmi.1652
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发表时间：
2016-01
影响因子：
--
通讯作者：
Regatte RR
中科院分区：
文献类型：
--
作者：
Lee JS;Xia D;Jerschow A;Regatte RR
化学交换饱和转移(CEST)是磁共振成像的一个重要研究领域，它为生物标志物和生理活性分子的放大检测和监测提供了对比机制。在生物组织器官中，多种内源性CEST因子共存，它们的CEST效应可能会重叠。对这种重叠的CEST效应的解释可以在表征源自不同代谢物的单个CEST效应时得到解决。在这项工作中，我们提供了在3T和7T的外磁场和不同的pH条件下，在生物组织和器官中常见的内源性CEST试剂的CEST效应的体外测量。结合在11.7T下测量的质子核磁共振谱，考虑了不稳定质子的化学交换率、化学位移和酸度，对这些CEST效应进行了评估。小分子代谢物的胺质子在3T时可能看不到，但在7T时可以探测到其中的一些，它们的CEST效应可能与共存的酰胺和羟基质子重叠。在3T和7T之间，CEST对比可能携带关于代谢物含量的不同信息。在CEST方法中，在3T时可能看不到胺质子，但在7T时可以探测到一些酸度较低的胺质子。
Chemical exchange saturation transfer (CEST) has been an intensive research area in MRI, providing contrast mechanisms for the amplified detection and monitoring of biomarkers and physiologically active molecules. In biological tissues and organs, many endogenous CEST agents coexist, and their CEST effects may overlap. The interpretation of such overlapped CEST effects can be addressed when the individual CEST effects originating from various metabolites are characterized. In this work, we present the in vitro measurements of the CEST effects from endogenous CEST agents that are commonly found in biological tissues and organs, at the external magnetic fields of 3 T and 7 T and under various pH conditions. Together with the proton NMR spectra measured at 11.7 T, these CEST effects have been evaluated in consideration of the chemical exchange rates, chemical shifts, and acidities of the labile protons. Amine protons of small metabolites might not be visible at 3 T, but some of them can be probed at 7 T, wherein their CEST effects may overlap with those from coexisting amide and hydroxyl protons. Between 3 T and 7 T, CEST contrast may carry different information regarding metabolites content. Amine protons may not be visible at 3 T by the CEST methodology, but some of them with lower acidity can be probed at 7 T.