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.