Cerebral angiography is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain.

Cerebral angiography is done in the hospital or large radiology center. You will be asked to lie on an x-ray table. Your head is positioned and held still using a strap, tape, or sandbags, so you do not move during the procedure. The health care provider will attach electrocardiogram (ECG) leads to your arms and legs, which monitor your heart activity during the test.

Before the test starts, you will be given a mild sedative to help you relax.

An area of your body, usually the groin, is cleaned and numbed with a local numbing medicine (anesthetic). A thin, hollow tube called a catheter is placed through an artery and carefully moved up through the main blood vessels in the belly area and chest and into an artery in the neck. Moving x-ray images help the doctor position the catheter.

Once the catheter is in place, a special dye (contrast material) is injected into catheter. X-ray images are taken to see how the dye moves through the artery and blood vessels of the brain. The dye helps highlight any blockages in blood flow.

After the x-rays are taken, the needle and catheter are withdrawn. Pressure is immediately applied on the leg at the site of insertion for 10 - 15 minutes to stop the bleeding. After that time, the area is checked and a tight bandage is applied. Your leg should be kept straight for 12 hours after the procedure.

Digital subtraction angiography (DSI) uses a computer to "subtract" or take out the bones and tissues in the area viewed, so that only the blood vessels filled with the contrast dye are seen.

You must sign a consent form. Your health care provider will explain the procedure and its risks.

Routine blood tests and examination of the nervous system will be done before the procedure.

Tell the health care provider if you:

• Are allergic to shellfish or iodine substances
• Have a history of bleeding problems
• Have had an allergic reaction to x-ray contrast dye or any iodine substance
• May be pregnant

You may be told not to eat or drink anything for 4 to 8 hours before the test.

When you arrive at the testing site, you will be given a hospital gown to wear. You must remove all jewelry.

The x-ray table may feel hard and cold. You may wish to ask for a blanket or pillow.

Some people feel a sting when the numbing medicine (anesthetic) is given. You will feel a brief, sharp pain as the catheter is inserted. There is a feeling of pressure as the catheter is moved into the body.

Some people feel a warm or burning sensation of the skin of the face or head when the contrast dye is injected.

You may have slight tenderness and bruising at the site of the injection after the test.

Cerebral angiography is most frequently used to identify or confirm problems with the blood vessels in the brain.

Your doctor may order this test if you have symptoms or signs of:

• Abnormal blood vessels (vascular malformation)
• Aneurysm
• Narrowing of the arteries in the brain
• Vasculitis

It is sometimes used to:

• Confirm a brain tumor
• Evaluate the arteries of the head and neck before surgery
• Find a clot that may have caused a stroke

In some cases, this procedure may be used to get more detailed information after something abnormal has been detected by an MRI or CT scan of the head.

This test may also be done in preparation for medical treatment (interventional radiology procedures) by way of certain blood vessels.

Contrast dye flowing out of the blood vessel may be a sign of internal bleeding.

Narrowed arteries may suggest cholesterol deposits, a spasm, or inherited disorders.

Out of place blood vessels may be due to brain tumors, bleeding within the skull, aneurysm (bulging of the artery walls), or arteriovenous malformation.

Abnormal results may also be due to:

• Intracerebral hemorrhage
• Metastatic brain tumor
• Neurosyphilis
• Optic glioma
• Pituitary tumor
• Primary brain tumors

There is the possibility of significant complications, including:

• Allergic reaction to the contrast dye
• Blood clot or bleeding at the needle stick site, which could partly block blood flow to the leg
• Damage to an artery or artery wall from the catheter, which can block blood flow and cause a stroke (rare)

Tell your health care provider immediately if you have:

• Facial weakness
• Numbness in your leg during or after the procedure
• Slurred speech
• Vision problems

Koenigsberg RA, Bianco BA, Faro SH, Stickles S, Hershey BL, Siegal TL, et al. Neuroimaging. In: Goetz, CG, eds. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 23.