Cerebral Angiography Imaging Procedures

The purpose of the cerebral angiography procedure is to determine how blood flows through the arteries of the brain and head. It is performed on stroke victims and in other situations where abnormal blood flow in the brain is suspected. The procedure provides a more detailed picture of blood flow through the brain than an MRI (magnetic resonance image) or CT (computerized tomography) scan, and it may also be used to determine the state of the arteries before surgery or to locate a suspected tumor.

Pre-procedure

• Samples of blood and urine may be taken, and a chest x-ray and/or electrocardiogram may be done, before the test begins. A sedative is administered to help the patient relax, usually through an IV (intravenous injection). The equipment that monitors vital signs during the procedure is attached (blood pressure cuff, heart monitor, etc.), and the head is held stationary by straps, tape or sandbags.

Procedure

• A tiny slit is cut in the artery for insertion of the catheter.

  The procedure requires that a dye or contrast be injected into the bloodstream to make the blood flow more visible for the x-ray equipment. This is done through a long plastic tube called a catheter, which is inserted into a large artery that supplies blood to the brain. Before the catheter is inserted, the injection site (usually the groin area) is treated with a local anesthetic.

  A small cut is made into the artery and a guide wire is inserted. The catheter is then pushed in over the guide wire. Watching its advance by way of an advanced imaging tool called a fluoroscope, the surgeon carefully works the catheter into the brain's blood vessels. Once the catheter is in place, the dye is injected and the x-rays are taken.

  When the tests have been completed satisfactorily, the catheter is removed and pressure is applied to the opening in the artery to stop the flow of blood. A bandage is then applied and the patient is taken to another area for observation.

Post-procedure

• The patient must lie flat and keep the head still for 6 to 8 hours after the procedure, during which time vital signs are monitored. It is recommended that assistance be provided in sitting up after this, as dizziness and light-headedness are common. After release from the hospital, the patient is advised to resume a regular diet, and not to exercise or drive for 48 hours. Drinking lots of liquids during this period helps flush the dye from the body. Coffee and alcohol should be avoided, since they dehydrate the body.

Risks

• A very rare but potentially fatal allergy to the dye occurs in one of every 50,000 to 150,000 people. Any allergy history should be discussed with your doctor before the procedure. Other risks include damage to the blood vessels from the catheter insertion, internal bleeding, infection and, rarely, stroke.