New approaches in the chemical design of gd-containing liposomes for use in magnetic resonance imaging of lymph nodes

Several approaches to Improve Gd-containing liposomes as magnetic resonance contrast medium for the visualization of lymph nodes are discussed. The modification of the liposome surface with a polymer was chosen as a chemical solution to control the contrast enhancement properties of the medium. It was found that liposome modification with Gd-diethylenetriaminepentaacetic acid (DTPA)-polylysine-based chelating polymer can increase several fold the metal load per vesicle, while surface modification with polyethylene glycol (PEG) might lead to the increased relaxivity of paramagnetic vesicles. Examples are given on how chemical modification of the liposome surface can improve the performance of Gd-containing liposomes in the visualization of lymph nodes.