Coronary arteriography, or coronary angiography, is used to detect coronary artery disease. In this procedure a special x-ray opaque dye is injected into the bloodstream through a thin plastic tube (catheter) which has been inserted into an artery in either the arm or groin and threaded through a vein to the arteries located inside the aorta--the body's main blood vessel which originates in the heart. Moving pictures are then taken of the heart with a special x-ray machine. If there are no obstructions, the dye flows smoothly through the arteries to all branches. Partial blockages appear as tiny breaks in the dye stream; complete blockages prevent the dye flowing into branches that otherwise would be visible with x-ray. Coronary arteriography is a valuable tool used by physicians to assess the extent of damage or disease in coronary arteries and determine the most appropriate treatment. Although there...