Advances in gadolinium-based MRI contrast agent designs for monitoring biological processes in vivo

Gadolinium-based MRI contrast agents have been widely used in clinical medicine for ∼30 years. Next generation designs for targeting specific biological structures or monitoring biological processes have been demonstrated in vivo. The sensitivity of such agents has been improved by optimizing their water exchange rates and molecular motions and signal amplification via nanoparticles is beginning to show promise. Trends in the latest designs are summarized in this article.