When doctors suspect a stroke or damage to the arteries in a person’s brain has occured, they may perform an MRI or CT scan. Sometimes, a magnetic resonance angiogram (MRA) can make the diagnosis when a CT scan or MRI does not. However, even an MRA may not be specific and may show only that there is an abnormality. If imaging detects an abnormality, the next step in diagnosing the problem is to do a cerebral angiogram, in which dye is injected into the bloodstream so x-rays can determine the flow and shape of the brain’s vessels.

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Arteries are not normally seen in an x-ray, so a special material called contrast dye is injected into one or both of the carotid arteries—the major blood vessels on either side of your trachea, where you can feel your pulse. The process is monitored by a fluoroscope, a special x-ray that sends the images to a TV monitor.

The contrast dye is injected into an artery in the groin or neck through a catheter, which is a piece of thin, soft tubing. Periodically a saline solution containing heparin, a blood thinner, is flushed through the catheter to prevent blood from clotting while the dye moves through the bloodstream. X-rays are taken, with the bones and tissues being filtered out by specialized computer software, leaving a picture of just the vessels and any abnormalities, such as leaks or ruptures where blood might be spilling out into other areas. These pictures can help doctors pinpoint a problem in the brain or evaluate the arteries of the head and neck before surgery.

The entire procedure takes 1 to 3 hours, and the patient must rest for 6 to 8 hours after the test. If no complications arise, the patient can leave the hospital the same day.

ADDITIONAL FACTS

  1. Patients remain conscious during a cerebral angiogram, and a nurse may occasionally ask questions or request that the patient do simple tasks in order to monitor how he or she is feeling.
  2. There is a slight sensation of pressure as the catheter moves through the artery and a hot, rushing feeling as the dye is injected.