Ultrasound is an essential diagnostic tool because of its safety, convenience and effectiveness. It produces images of the body's internal structures through the use of high-frequency sound waves, the echoes of which are used to create moving and still images. All images appear in "real" time as soon as the machine is turned on, and the transducer (a handheld device that sends and receives sound waves) placed on the body; there is no wait, as there is for X-rays and other imaging procedures, for images to be developed.
Carotid ultrasound is used to examine the two carotid arteries, which are located on either side of the neck. The carotid arteries divide into internal and external; the internal ones supply blood to the brain, and the external ones supply blood to the face, neck and scalp.
Candidates for Carotid Ultrasound
Carotid ultrasound is typically performed to look for artery-clogging plaque, which can lead to strokes or other serious complications. A candidate for carotid ultrasound has recently had a stroke or mini-stroke; has a carotid bruit, which is an abnormal sound in the artery that is heard under stethoscopic examination; is suspected of having a blood clot in an artery; is suspected of having a split in the wall of the artery; has recently had carotid endarterectomy to clear a blockage; or has recently had a stent inserted. Carotid ultrasound is also used as a preventive screening test for anyone at high risk for having a stroke.
The Carotid Ultrasound Procedure
The ultrasound procedure begins with the patient's lying down on an examination table. A water-based gel is applied to both sides of the neck. The gel allows consistent contact between the body and the transducer by eliminating any air pockets that could get in the way. The transducer is held firmly against the skin, and slowly moved back and forth; the images then appear on the computer screen. The procedure usually takes 15 to 30 minutes.