This patent describes and claims: ???A coating for visualizing medical devices in magnetic resonance imaging, comprising a complex of formula (III): P-X-J-L-Mn+(II), wherein P is a polymer, X is a surface functional group selected from the group consisting of an amino group and a carboxyl group, L is a chelate, M is a paramagnetic ion, n is an integer that is 2 or greater and J is the linker or sp