Cerebral angiography is an invasive diagnostic procedure in which a physician is able to examine the blood vessels in the brain by injecting a dye into the circulatory system, then expose the tissue with x rays. The dye makes the blood vessels appear on the x-ray film.
Angiography is a way of producing pictures (angiograms) of internal structures by introducing into the circulatory system dyes (contrast media) that show up on x-ray film when a tissue is exposed to x rays. In a cerebral angiogram, doctors examine the blood vessels in the brain. From this procedure, they can determine if a blood vessel is narrowed by plaque build-up or blocked by a clot. Often this procedure is performed when A stroke is suspected or when an MRI or CT scan has suggested an abnormality in the blood vessels. Cerebral angiography can also detect tumors and bulges in the artery wall (aneurysms). A cerebral angiogram may be done in conjunction with another procedure in the brain in order to provide the doctor with the most precise information available.
Significant risks are associated with cerebral angiography. Individuals who are allergic to iodine or iodine-containing foods such as shellfish may have an allergic reaction to the contrast medium (dye). This reaction can be severe and may cause difficulty breathing, A sudden drop in blood pressure, loss of consciousness, tissue swelling, and other symptoms of anaphylactic shock. If a cerebral angiogram is recommended, patients should inform their physician of any allergies, including food allergies. Patients should also inform their doctor if they have any bleeding or clotting problems or if they may be pregnant.
In order for this procedure to be performed, the individual is placed on an x-ray table and the head is immobilized. Electrodes that monitor the heart beat (an electrocardiogram or ECG) are attached to the body. Heart function is monitored throughout the test. Intravenous fluids are often started at this time. The area where they dye is to be injected is shaved and cleaned. Usually the dye is injected into an artery in the leg.
A local anesthetic is given at the site of the dye injection, and then a needle is inserted into the artery followed by a thin, flexible tube (catheter). Dye is then injected through the catheter. The individual may have a hot, uncomfortable feeling in the head as the dye reaches the arteries in the brain. This feeling usually lasts no longer than 20 seconds. X rays are taken once the dye reaches the brain. The individual must hold still when the x rays are taken. When the x rays are complete, the catheter is removed. Pressure is applied to the injection site to prevent bleeding.
Individuals should not to eat or drink for up to 8 hours before the procedure. Individuals who take blood-thinning medication, such as aspirin or coumadin, will need to discontinue taking them before the procedure. Discontinuing any medications should be done only at the advice of the patient's doctor. A doctor will give specific directions on when blood-thinning medications should be stopped. Blood tests are normally done up to a week before non-emergency cerebral angiography. A sedative drug is given shortly before the procedure to help the individual relax and remain calm.
After cerebral angiography, the individual must remain lying flat for 6 hours. During this time a nurse will monitor the individual for complications. The intravenous line is removed when the individual is able to drink fluids. Depending on the appearance of complications and the health of the individual, an overnight stay in the hospital may be necessary. Otherwise, the individual is released after the resting period. Someone must be available to drive the person home and ideally to stay with them for the next 24 hours. Heavy lifting should be avoided for the next two or three days.
In addition to allergic reactions to the dye, complications include damage to the artery by the needle or catheter used to inject the dye. Debris on the artery wall (plaque) can be dislodged by the procedure and block the artery. Blockage can cause stroke. In addition, A clot can form at the injection site that blocks the artery in the leg.
Contrast media— Dyes injected into the circulatory system that when exposed to x-rays, make it possible to see blood vessels and other soft tissue.
Plaque— A mixture of fat, cholesterol, and cellular debris that builds up in the inner lining of an artery.
Normally cerebral angiography produces a clear picture of the blood vessels and pinpoints any structural abnormalities or blockages. This test gives more precise results than a CT scan or MRI. Based on the pictures obtained, additional procedures to unblock an artery or correct a structural abnormality may be necessary.
Health care team roles
Cerebral angiography is done in a hospital setting. The health care team includes at minimum a nurse to monitor heart function and vital signs, a radiology technician, and a radiologist. A nurse will monitor the individual during the rest period following the procedure.
American College of Radiology. 1891 Preston White Drive, Reston, VA 20191. (703) 648-8900. 〈http://www.act.org〉.
Brown, Jeffrey. "Cerebral Angiography." MedlinePlus Encyclopedia. November 3, 2004. 〈http://www.nlm.nih.gov/medlineplus/ency/article/003799.htm〉 (November 19, 2005).
Washington University in St. Louis School of Medicine. "Cerebral Angiography." The Internet Stroke Center. 2003. 〈http://www.strokecenter.org/pat/diagnosis/angio.htm〉 (November 25, 2005).
University of Iowa. "Cerebral Angiogram Test." Virtual Hospital June 2000. 〈http://www.vh.org/adult/patient/neurology/cerebralangiogramtest/index.htm〉 (November 8, 2005).