Angiography is a medical imaging technique used to visualize the inside of blood vessels and organs of the body, especially in the arteries, veins and the heart chambers. This is done by injecting contrast agents into the bloodstream through a thin plastic tube (catheter), which is placed directly in the blood vessel.

Angiography is used to provide information about blood vessel abnormalities, such as narrowing, blockage, inflammation, abnormal widening and bleeding. It can also be used to guide procedures where abnormal blood vessels need to be closed if they are bleeding, or can be part of other medical investigations or surgical treatments.