An angiography is an x-ray of the arteries. The arteries are not normally seen in an x-ray, so a special material, called contrast dye, is injected into one or more arteries to make them visible. For a cerebral angiography, the contrast dye is injected into one or both of the carotid arteries in the neck.

This test is done in the hospital. You will lie on the x-ray table. Your head is positioned and immobilized by using a strap, tape, or sandbags. Electrocardiogram (ECG) leads are taped to your arms and legs to monitor your heart during the test.

The area where the contrast dye will be injected is shaved and cleansed. The site is usually in the leg. You are given medicine to numb the area, the artery is punctured, and a needle is inserted into the artery.

A long, narrow, flexible tube (catheter) is inserted through the needle and into the artery. It is then threaded through the main blood vessels of the abdomen and chest until it is properly placed in the arteries of the neck. This procedure is monitored by a fluoroscope (a special x-ray that projects the images on a TV monitor).

The contrast dye is then injected into the neck area through the catheter, and the x-ray pictures are taken. The catheter is kept open by flushing it periodically with a saline solution containing heparin, which will keep the blood in the catheter from clotting( hardening). Your pulse, blood pressure, and breathing are monitored during the procedure.

After the x-rays are taken, the needle and catheter are withdrawn.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 region viewed, so that only the blood vessels filled with the contrast dye are seen.

• Tell the health care provider if you are pregnant or if you have ever had any bleeding problems. Allergic reactions to x-ray contrast dye or any iodine substance, as well as any other allergic reactions, should be mentioned.
• You must sign a consent form.
• Routine blood tests will be done and an examination of the nervous system performed before the procedure.
• Food or fluid may be restricted 4 - 8 hours before the procedure.
• You will be given a hospital gown to wear. You must remove all jewelry.
• A sedative or pain pill may be given to you before the procedure.

The x-ray table may be hard and cold, but you may ask for a blanket or pillow. There is a brief sting when the local anesthetic (numbing medicine) is given. This medicine does not numb the artery, so there will be brief, sharp pain as the catheter is inserted into the artery. There is a slight feeling of pressure as the catheter moves through your blood vessels.

As the dye is injected, there may be a warmth or burning sensation. You may experience a slight headache or feel flushed on the side of the face. There may be slight tenderness and bruising at the site of the injection after the test.

The test is most frequently used to confirm cases of stroke, tumor, bulging of the artery walls, a clot, or a narrowing of the arteries. It is also done to evaluate the arteries of the head and neck before surgery. This procedure is used to get more exact information after something abnormal has been detected by an MRI or CT scan of the head. An example of such abnormality would be bleeding within the brain.

If the contrast dye flows out of the blood vessel, it may indicate internal bleeding. Narrowed arteries may suggest cholesterol deposits, a spasm, or inherited disorders. If the vessels are displaced, it may be caused by tumors or bleeding within the skull, aneurysm (bulging of the artery walls), or malformation.

Additional conditions under which the test may be performed:

• Arteriovenous malformation (cerebral)
• Cerebral aneurysm
• Hypertensive intracerebral hemorrhage
• Intracerebral hemorrhage
• Lobar intracerebral hemorrhage
• Metastatic brain tumor
• Neurosyphilis
• Optic glioma
• Pituitary tumor
• Polycystic kidney disease
• Primary brain tumor
• Stroke secondary to carotid dissection
• Stroke secondary to carotid stenosis
• Stroke secondary to FMD
• Stroke secondary to syphilis
• Syphilitic aseptic meningitis

There is the possibility of significant complications:

• A reaction to the contrast dye can occur.
• There is some risk of the catheter damaging the artery or knocking loose a piece of the artery wall, which can block blood flow and cause a stroke. This is rare, however.
• A clot or bleeding at the puncture site may result in a partial blockage of the blood flow to the leg.

Let your health care provider know immediately if you have:

• Facial weakness
• Slurred speech
• Visual trouble
• Numbness in your leg during or after the procedure