Coronary angiography is a diagnostic procedure used to visualize the coronary arteries, which supply blood to the heart muscle. It involves injecting a contrast dye into the coronary arteries to allow X-ray imaging of the blood flow through these vessels. This procedure helps in detecting blockages, narrowing, or other abnormalities in the arteries that can lead to heart disease. Coronary angiography is commonly performed to assess the extent and severity of coronary artery disease and to guide treatment decisions such as angioplasty or bypass surgery.