Synthesis and Relaxometric Characterization of a New Mn(II)-EDTA-Deoxycholic Acid Conjugate Complex as a Potential MRI Blood Pool Agent

Gd(III)-complexes have been employed for more than twentyfive years as MRI contrast agents. In the last decade, considerations about potential toxicity of residual gadolinium in patients suffering from severe kidney diseases have moved researchers to evaluate alternative solutions, among them Mn(II)-complexes, to shorten T₁ and achieve good image contrast. In this article we report on the synthesis of a new Mn(II)-chelate, endowed with a deoxycholic acid residue designed to interact reversibly with serum albumin and to boost the usually low relaxivity associated with Mn(II)-complexes. Its detailed relaxometric characterization and the analysis of albumin binding behaviour showed remarkable properties, suggesting its potential use as MRI blood pool agent.