There are a number of diagnostic exams that can be performed to determine if someone has had a stroke or is at risk for having one.
When a stroke is suspected:
Computed tomography (CT)
The first diagnostic test performed in the emergency room is usually a CT scan. CT uses computers to generate detailed pictures of the brain and can confirm the diagnosis of stroke and tell whether the stroke is caused by a hemorrhage in the brain.
Magnetic resonance imaging (MRI)
MRI is a diagnostic test that may be performed to identify and further localize the site of the stroke and find the source. It may be able to quickly identify the area deprived of sufficient blood flow and guide further therapy.
An angiogram is an X-ray in which a contrast agent, or dye, is injected to highlight the blood vessels. With this exam, radiologists can pinpoint the exact location of blockage or bleeding in the brain. Angiography also is used to guide thin tubes called catheters to the site of the problem and administer treatments.
Determining who is at risk:
Your doctor may be able to assess your risk for stroke during a routine physical examination. If your physician suspects that you may be at high risk, he or she will ask if you have experienced symptoms such as numbness or muscle weakness, speech or vision difficulties, or lightheadedness. By listening to the carotid artery through a stethoscope, the doctor may hear a rushing sound, called a bruit that suggests the artery may be obstructed. Physical exam is not always accurate, however, and further tests may be ordered.
A technique called Doppler ultrasound that creates pictures using sound waves can determine whether there is blockage in the arteries that carry blood to the brain. Some physicians recommend ultrasound screening for those who have been diagnosed with atherosclerosis or other risk factors for carotid artery disease.
Magnetic resonance angiography (MRA)
This is a noninvasive diagnostic technique that creates an image of the arteries in the brain. A magnetic resonance (MR) scanner uses harmless but powerful magnetic fields and radio waves to create detailed images of the body's tissues.
Reprinted with permission of the Society of Interventional Radiology © 2004, www.SIRweb.org. All rights reserved.