Gadolinium-conjugated dendrimer nanoclusters as a tumor-targeted T1 magnetic resonance imaging contrast agent.

Contrast agents are increasingly being used in diagnostic magnetic resonance (MR) imaging to help detect and characterize pathological abnormalities. In fact, it has been estimated that nearly 50% of all MR examinations already involve the use of MR contrast agents, with chelated gadolinium compounds being by far the most widely used.[1,2] Most clinically relevant Gd-based agents are small, non-targeted compounds that passively distribute into the intravascular and interstitial space.[3] However, there has recently been emerging interest in the development of paramagnetic contrast agents that are capable of probing the molecular profile of tissues via ligand targeting, enzymatic activity and multiplexing.[4,5] It is envisioned that these agents could be used to acquire a more specific clinical diagnosis and thus improve patient management.