A cerebral angiogram (or arteriogram) is a diagnostic test that produces images of the arteries in the brain and/or head and the blood flowing through them. It can help physicians diagnose a number of problems with the blood vessels in the head and neck, including ruptured vessels or blockage of an artery, usually by fatty plaque. If a vessel is blocked, the patient may be at increased risk of stroke. Other conditions (such as a cerebral aneurysm) may also be revealed through a cerebral angiogram.

To perform an angiogram, the physician injects a special dye (contrast medium) into the arteries of the head or brain through a long, thin tube called a catheter. The catheter is threaded through a blood vessel, usually in the upper thigh and into the head. Once the catheter is in place, the physician injects the dye through the catheter and into the targeted arteries. After the dye has reached the arteries, the x-ray images can be taken.

Although the physician typically numbs the area where the catheter is inserted, the patient is awake for the entire procedure. The patient receives a mild sedative before the procedure and usually does not feel the movement of the catheter within the blood vessels. However, there may be some sensation, such as heat or flushing, as the dye is released.

Preparations for the test may vary and patients are encouraged to discuss the matter with their physicians. The test is usually performed on an outpatient basis and patients generally return home the day of the test. They may be  placed on bed rest for 24 hours following the procedure. In some cases, patients will remain in the hospital for observation or further tests.

The most common risk associated with cerebral angiograms is an allergic reaction to the contrast medium. Patients should inform their physicians of any known allergies, especially to iodine, shellfish or strawberries. There is also a risk that the catheter will rupture an artery or dislodge a piece of plaque that can block blood flow and cause a stroke. Women who are pregnant or trying to become pregnant or who are nursing need to discuss the use of this test with their physicians. Angiograms are usually not done on pregnant women due to the risk of damage to the fetus by radiation.