Angiography is an imaging test that uses X-rays to view your body’s blood vessels. The X-rays provided by an angiography are called angiograms. This test is used to study narrow, blocked, enlarged, or malformed arteries or veins in many parts of your body, including your brain, heart, abdomen, and legs.
Depending on the type of angiogram, access to the blood vessels is gained most commonly through the femoral artery, to look at the left side of the heart and at the arterial system; or the jugular or femoral vein, to look at the right side of the heart and at the venous system. Using a system of guide wires and catheters, a type of contrast agent (which shows up by absorbing the X-rays), is added to the blood to make it visible on the X-ray images.
The X-ray images taken may either be still, displayed on an image intensifier, or film or motion images. For all structures except the heart, the images are usually taken using a technique called digital subtraction angiography or DSA. Images, in this case, are usually taken at 2–3 frames per second, which allows the interventional radiologist to evaluate the flow of the blood through a vessel or vessel. This technique “subtracts“ the bones and other organs so only the vessels filled with contrast agents can be seen.
The heart images are taken at 15–30 frames per second, not using a subtraction technique. Because DSA requires the patient to remain motionless, it cannot be used on the heart. Both these techniques enable the interventional radiologist or cardiologist to see stenosis (blockages or narrowings) inside the vessel which may be inhibiting the flow of blood and causing pain.
Coronary angiography is a test to find out if you have a blockage in a coronary artery. Your doctor will be concerned that you’re at risk of a heart attack if you have unstable angina, atypical chest pain, aortic stenosis, or unexplained heart failure. During coronary angiography, a contrast dye will be injected into your arteries through a catheter (thin, plastic tube), while your doctor watches how blood flows through your heart on an X-ray screen.This test is also known as a cardiac angiogram, catheter arteriography, or cardiac catheterization.