Kilogram scale facile synthesis and systematic characterization of a Gd-macrochelate as T1-weighted magnetic resonance imaging contrast agent oleh Meng Shi, Wei Xiong, Jie Feng, Lihe Wu, Jing Yang, Yudie Lu, Xuanyi Lu, Qingdeng Fan, Hemin Nie, Yunlu Dai, Chenggong Yan, Ye Tian, Zheyu Shen