肝胆特异性对比剂在MRI诊断肝癌中具有重要的价值，但是，现有此类对比剂尚有肝胆靶向性不高、肾排泄多、肝胆显像延迟时间长等缺点。小分子胆酰肌氨酸（CSar）具有肝胆靶向性高、血浆-肝细胞转运快、肝细胞-胆汁分泌迅速、经肠道原型排泄等优点，可作为母体靶头构建新型高性能MRI肝胆特异性对比剂。因此，本研究基于前期成功设计并合成肝胆疾病方面新型化合物的工作基础，将Gd螯合物与CSar进行偶联，设计新型对比剂Gd-DTPA-CSar和Gd-EOB-DTPA-CSar，探索该类化合物的最佳合成路径。进而，与常规肝胆特异性对比剂Gd-EOB-DTPA对照，进行稳定性、细胞毒性、急性毒性、体内分布和动物MRI研究（药代动力学、肝损伤模型和VX2肝癌模型），探索其潜在临床价值。这将为构建高品质、安全性有保障的新型MRI对比剂提供理论依据。

Hepatobiliary-specific contrast agent is of great value for MRI in the diagnosis of liver cancer, but these existing contrast agents are still limited in a low hepatobiliary targeting, high renal excretion and long delay time of hepatobiliary imaging. Because of its high hepatobiliary targeting, rapid blood-to-liver uptake and liver-to-bile excretion, intestinal excretion in a prototype and other advantages, a small molecule cholylsarcosine (CSar) could be used as targeting structure matrix to develope a novel hepatobiliary-specific MRI contrast agent with high performance. On the basis of the successful design and synthesis of new compounds of hepatobiliary disease, we designed these Gd-chelate coupling CSar compounds of Gd-DTPA-CSar and Gd-EOB-DTPA-CSar. We want to explore the optimal synthesis route of these compounds. Thus, to explore the clinical potential of these compounds, conventional hepatobiliary-specific MRI contrast agent (Gd-EOB-DTPA) will be used as control to compare the stability, cytotoxicity, acute toxicity, in vivo distribution and animal MRI (pharmacokinetics, liver injury model and VX2 liver cancer model). This project will provide a theoretical basis for the construction of a novel MRI contrast agent with a high quantity and safety.