An implantable prosthesis can comprise a strut having a lumen, radiopaque particles within the lumen, and a polymer binder. The polymer binder retains the radiopaque particles within the lumen. The strut may have side holes through which a therapeutic agent may pass and through which the radiopaque particles are incapable of passing. The polymer binder may be absent or optional. The radiopaque particles can have sizes that prevent them from escaping out of the lumen through the side holes. The radiopaque particles placed within the lumen can improve visualization of the prosthesis during an implantation procedure.