Multilocus Binding Increases the Relaxivity of Protein-Bound MRI Contrast Agents

摘要

The utility of clinical magnetic resonance imaging(MRI)has been greatly expanded by the use of contrast agents- gadolinium complexes that serve to increase the longitudinal nuclear relaxation rate(1/7^)of water protons.Commercial contrast agents are only effective at high concentrations(> 0.1 mM)and,as a result,there has been considerable effort to increase their sensitivity.One approach is to increase the number of gadolinium ions in the molecule by making polymeric or dendrimeric contrast agents.'11 A second approach is to optimize the parameters that influence relaxation enhancement,such as rotational diffusion and water exchange.