For example, coronary angiography is an angiogram of the coronary arteries to check whether there is a stenosis of the coronary arteries and the location of the stenosis, and to estimate the extent of the stenosis. The angiogram is performed by passing the appropriate artery, such as the femoral or radial artery, through a specific catheter to the site of the vessel to be examined and injecting a small amount of iodine-containing contrast agent to clearly visualize the vessel for the purpose of examining it.