Overview

An angiogram, also called an arteriogram, is a type of x-ray that takes pictures of your blood vessels with the help of a contrast agent that is injected into your arteries through a catheter. This test can help your doctor diagnose a stroke, aneurysm, arteriovenous malformation (AVM), tumor, clots, and arterial stenosis (narrowing of the arteries due to atherosclerosis).

How does an angiogram work?

A typical x-ray works by casting a "shadow" on film when it is exposed to the x-ray, much like when you hold a flashlight up to your hand and cast a shadow on a wall. Normally your blood vessels cannot be seen in an x-ray, but adding a contrast agent into the blood stream through a catheter makes your blood vessels show up on the film, sort of like a roadmap (Figure 1).

A machine called a fluoroscope, also called a C-arm, is an arc shaped piece of equipment that generates x-rays from one side and photographs them on the other side (Figure 2).

Today many catheter angiographic studies have been replaced by less invasive methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) that do not require a catheter be inserted. Catheter angiography has the benefit of combining diagnosis and treatment in patients who may undergo surgery or other endovascular procedure such as angioplasty, coiling, balloon, or stent placement.

What does an angiogram show?

Angiograms are very good at detecting problems with the blood vessels such as an aneurysm, arteriovenous malformation (AVM), arterial stenosis (narrowing of the arteries due to atherosclerosis), tumor, and clots (Figure 3).

How does the contrast agent work?

The contrast agent contains iodine, a substance that x-rays cannot pass through. The contrast circulates through your blood stream and can be x-rayed as it passes through the neck, brain or spinal column.

Who performs the test?

A doctor who specializes in interventional radiology will perform the test in the Special Procedures room or Angiography suite of the Radiology department.

How should I prepare for the test?

Don't eat or drink after midnight on the night before the test. You should take your normal morning medication with a small amount of water. Make arrangements to have someone drive you to and from the hospital. Before the test, you will be asked to change into a hospital gown and an intravenous (IV) line will be placed in your arm. The radiologist or nurse will discuss the test with you, explain the risks, answer any questions, and have you sign consent forms.

What happens during the test?

Step 1. prepare the patient
You will lie on your back on an x-ray table, and your head will be positioned so that it won't move during the test. Your blood pressure and heart rate will be monitored throughout the test.

Step 2. insert the catheter
In order to deliver the contrast agent to the correct arteries, a catheter--or long, flexible, soft plastic tube--must be used. The catheter is inserted into an artery, usually the femoral artery in your groin area, through a needle. The groin area is first shaved and cleansed. A numbing agent is used to minimize discomfort as an incision is made to locate the artery. The catheter is inserted and then carefully guided through your arterial system to the correct position in your neck or brain (Figure 4). Your doctor views and guides the catheter with the help of a fluoroscope (a type of x-ray that shows images on a TV monitor). You may feel brief pain when the catheter is inserted, but most catheter manipulation is painless.

Step 3. take x-ray pictures
When the catheter is in the correct place, your doctor will inject the contrast agent while x-ray pictures are taken. You will feel a hot, flushed sensation lasting from 5 to 20 seconds. At this point you should remain very still so that the x-ray images will not be blurred. This may be repeated several times in order to view all necessary arteries.

What happens after the test?

Once the x-rays have been taken, the catheter will be removed and pressure is applied to the puncture for about 10-15 minutes so that your artery won't bleed. A bandage may be tightly applied, and you must stay on your back in bed for the next six hours, keeping your leg as straight as possible. In some instances, a puncture closure may be used which will allow you to get up and move around sooner. Notify your nurse if you notice any pain, swelling or bleeding.

What are the risks?

An angiogram is an invasive test, so it is not without risk. There is a very small risk of the catheter damaging your artery or loosening a piece of plaque lining the artery wall. This loose piece of plaque can travel up the artery into the brain and could block blood flow causing a stroke.

Some people are sensitive to the contrast agent used. The most common side effects from the iodine contrast are a brief metallic taste in your mouth and a feeling of warmth throughout your body.

An extremely rare reaction occurs when you experience severe hives and have difficulty breathing. Medications such as antihistamines can reverse this reaction. If you have diabetes or kidney problems you may experience kidney failure, but this too is extremely rare.

Be sure to tell you doctor if you are pregnant or have a history of allergies (to medications, previous iodine injections, or shellfish), diabetes, asthma, a heart condition, kidney problems, or thyroid conditions. Also tell them if you take any blood thinning medication such as aspirin or Coumadin.

How do I get test results?

The radiologist will promptly review your images and communicate directly with your referring doctor, who in turn will discuss the results with you.

Sources & links

If you have further questions about this diagnostic test, contact the doctor that ordered the test or visit:

www.radiologyinfo.org
www.nlm.nih.gov/medlineplus/diagnosticimaging.html

Glossary

aneurysm: a bulge or weakening of an arterial wall.

angiogram: a type of X-ray that takes pictures of blood vessels with the help of contrast dye injected via a catheter.

arteriovenous malformation (AVM): a congenital disorder in which there is an abnormal connection between arteries and veins without an intervening capillary bed.

atherosclerosis: A degenerative disease of the arteries in which fatty plaques and scar tissue form on the inner walls and block the free flow of blood.

catheter: a thin flexible tube made of rubber or plastic used to insert or remove fluids from the body.

contrast agent: a liquid (usually iodine or gadolinium) that is injected into your body to make certain tissues show up clearly during diagnostic imaging (angiography, CT, myelogram, MRI).

fluoroscope: an imaging device that uses x-ray or other radiation to view structures in the body in real time, or "live." Also called a C-arm.

iodine: a non metallic element used in contrast agent that makes vessels and tissues show up on diagnostic imaging (angiogram, CT, myelogram).

radiologist: a doctor who specializes in reading X-rays and other diagnostic scans.

X-ray: electromagnetic radiation used in diagnostic imaging to view shadows of tissue density in the body, also called roentgenogram.

updated: 6.2004
reviewed by: Thomas Tomsick, MD