Gadolinium Complex of 1,4,7,10-Tetraazacyclo­dodecane-1,4,7-trisacetic Acid (DO3A)–Ethoxybenzyl (EOB) Conjugate as a New Macrocyclic Hepatobiliary MRI Contrast Agent

We report the synthesis of a macrocyclic
Gd chelate based on a 1,4,7,10-tetraazacyclo­dodecane-1,4,7-trisacetic
acid (DO3A) coordinationn cage bearing an ethoxybenzyl (EOB) moiety
and discuss its use as a T1 hepatobiliary
magnetic resonance imaging (MRI) contrast agent. The new macrocyclic
liver agent shows high chelation stability and high r1 relaxivity compared with linear-type Gd chelates, which
are the current clinically approved liver agents. Our macrocyclic,
liver-specific Gd chelate was evaluated in vivo through biodistribution
analysis and liver MRI, which demonstrated its high tumor detection
sensitivity and suggested that the new Gd complex is a promising contrast
agent for liver cancer imaging.