Gadolinium Endohedral Metallofullerene-Based MRI Contrast Agents

Abstract

With the ability to encapsulate and carry the highly paramagnetic Gd 3+ ion, gadolinium endohedral metallofullerenes or "gadofullerenes" are being explored as alternatives to the chelate complexes that are currently used for contrast-enhanced magnetic resonance imaging (MRI). Reviewed here are the various water-soluble derivatives of the gadofullerenes Gd@C 82 , Gd@C 60 , and Gd 3 N@C 80 that have been investigated as MRI contrast agents. The water proton r 1 relaxivi-ties of gadofullerenes can be more than an order of magnitude higher than those of clinically used chelate agents. Gadofullerene relaxivity mechanisms have been studied, and multiple factors are found to contribute to their high relaxivities. In vitro and in vivo T 1-weighted MRI tests of gadofullerene derivatives have shown their utility as bright image-enhancing agents. The gadofullerene MRI contrast agents are a promising new and unique style of gadolinium carrier for advanced imaging applications, including cellular and molecular imaging.