A device intended to be implanted during coronary artery bypass graft surgery, at the point of the arterial anastomosis, to provide clear postsurgical radiographic verification of the arterial anastomosis. It is in the form of a synthetic polymer ring (e.g., silicone) impregnated with a metal [e.g., tungsten (W)] to aid visualization, and is compatible with the imaging system with which it is intended to be visualized/exposed [e.g., magnetic resonance imaging (MRI), fluoroscopy].