. . "This patent describes and claims: ???A coating for visualizing medical devices in magnetic resonance imaging, comprising a complex of formula (II): 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" . .