Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, United States.
Curr Opin Chem Biol. 2013 Apr;17(2):167-74. doi: 10.1016/j.cbpa.2012.12.012. Epub 2013 Jan 17.
The rate of water exchange in lanthanide complexes is often overlooked as an important parameter in the design of responsive MR imaging agents. Most often, the number of inner-sphere water coordination sites or the rotational mobility of the complex is considered as the central theme while water exchange is either assumed to be "fast enough" or entirely ignored. On the contrary, relaxation and shift theories predict that water exchange rates may indeed be the key parameter one should consider in any new molecular design. In this short review, the impact of water exchange rates on three classes of lanthanide-based MRI contrast agents, T₁-based relaxation agents, T₂ exchange line-broadening agents and chemical exchange saturation transfer (CEST) agents, is illustrated and discussed.
水交换率在镧系配合物中通常被忽视，是设计响应性磁共振成像试剂的一个重要参数。大多数情况下，内球水配位位点的数量或配合物的旋转迁移率被认为是中心主题，而水交换要么被假定为“足够快”，要么完全被忽略。相反，弛豫和位移理论预测，水交换速率实际上可能是在任何新的分子设计中都应该考虑的关键参数。在这篇简短的综述中，讨论并说明了水交换率对基于镧系元素的三类磁共振成像对比剂的影响，基于 T₁弛豫的试剂、T₂交换线增宽试剂和化学交换饱和转移（CEST）试剂。
