Kidney blood vessels. Angiography blood vessel X_ray footage showing a radio_opaque contrast medium dark being injected by a catheter right into a 35_year_old patient磗 right renal artery. This is one of the vessels that supplies blood to the kidney grey mass at left. This is a healthy kidney, and the radio_opaque contrast medium visible on X_rays highlights normal structure and function, including the parenchyma and the kidney磗 blood vessels.