Angiography is an imaging technique used to visualize the inside of blood vessels and heart chambers. It is generally a safe and painless procedure. The image obtained from the technique is called an angiograph or angiogram.
Since the blood vessels are not highlighted clearly on ordinary X-rays, a special dye is injected into the blood vessel. The dye shows up in the X-ray imaging thereby highlighting the blood vessels. To visualize the left side of the heart and at the arteries access to the blood vessels is gained most commonly through the large artery in the thigh (femoral artery). To visualize the right side of the heart and at the veins access to the blood vessels is gained through the vein accompanying the femoral artery.
Angiograph helps detect blockages or narrowing (stenosis) inside the blood vessel. Coronary angiography is used to visualize the arteries supplying the heart. Angioplasty can be performed during a coronary angiogram. Small blood vessels are visualized through micro angiography. The blood vessels of the brain are visualized through neuro-vascular angiography. Narrowing of vessels in the extremities may be identified with peripheral angiography.