Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers.
This is traditionally done by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy.
An angiogram of a coronary artery.
Image credit: "Angiography." The Gale Encyclopedia of Medicine, edited by Jacqueline L. Longe, 5th ed., Gale, 2015. Gale OneFile: Health and Medicine, https://link.gale.com/apps/doc/PC4205141143/HRCA?u=nysl_me_sfc&sid=HRCA&xid=6c76e442. Accessed 29 Aug. 2020.