MR Lymphangiography Using Nano-Sized Paramagnetic Contrast Agents with Dendrimer Cores

Imaging of the lymphatic system is difficult because its channels and lymph nodes are small and not directly accessible. Currently, two clinical methods, the direct lymphangiography and the lymphoscintigraphy, are used to visualize parts of the human lymphatic system, but have significant limitations. Nano-sized contrast agents have recently been evaluated to be advantageous for visualization of the lymphatic system because of their appropriate physical sizes and the potential of signal amplification. In this review, the magnetic resonance lymphangiography using a series of nano-sized paramagnetic contrast agents, gadolinium labeled dendrimers, is discussed focusing on the synthetic method, their pharmacokinetic characteristics for selection of appropriate agents, and applications for visualization of various lymphatic disorders in mouse models.