However, to accurately record velocity using color Doppler ultrasonography, the angle must be between 30° and 60°. The ultrasound beam should be perpendicular to the skin, with a linear probe generating a grayscale image. Placing a pillow induces a poor evaluation window for the carotid artery and therefore normally should not be used.Īn adequate acoustic angle is important in obtaining an accurate color Doppler image. The neck of the patient should be relaxed and the chin should be slightly raised. Tilting the face too far from the test site can distort the anatomy or compress blood vessels, especially veins. The optimal position for tilting the head of the patient is approximately 45° away from the relevant artery. However, obtaining right-posterior projections is difficult. This position makes it easy to control the ultrasound probe. The examiner generally uses their right hand to evaluate both carotid arteries. A lateral sitting position is used for most ultrasonography examinations. However, the examiner should be familiar with the practice of using both hands. This position provides an expanded sonic window with a clear view of the carotid artery and allows many ultrasound probing positions. 1 In the overhead position, the examiner sits behind the head of the patient beside the end of the bed and uses both hands in the test. Your doctor should have the results within a few days.Īlways consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.The examiner can observe the carotid artery from either an overhead or a lateral sitting position. The radiologist then makes measurements from the video picture and submits a report to your doctor. The technician records the test on videotape for review by a radiologist. How long is it before the result of the test is known? Must I do anything special after the test is over? The other side of your neck is checked in the same way. As the equipment measures the blood flow through the artery, you hear a noise that sounds like your heartbeat. As the technician moves the sensor back and forth on your neck, different views of the carotid artery appear on the screen. What happens when the test is performed?Īfter squirting some clear jelly onto one side of your neck to help the ultrasound sensor slide around easily, a technician places the sensor against your skin. This test is often used to evaluate people who have had a stroke or who might be at high risk for one because of reduced blood flow in the carotid arteries. With this imaging technique, your doctor can see if there is any narrowing of your carotid arteries because of cholesterol deposits or some other problem. Using the Doppler effect-the change in the frequency of sound or light waves as they bounce off a moving object-this kind of ultrasound produces an image of blood in motion.Ī Carotid ultrasound shows the amount of blood flow in the carotid arteries, the major blood vessels to the brain located on either side of your neck. A computer transforms these echoes into an image that is displayed on a monitor.ĭoppler ultrasound is a variation of this technique that not only shows internal structures but also examines the flow of blood through blood vessels. ![]() The transducer sends sound waves into your body and picks up the echoes of the sound waves as they bounce off internal organs and tissue. ![]() After coating a small area of your skin with a lubricant to reduce friction, a radiologist or ultrasound technician places an ultrasound transducer, which looks like a microphone, on your skin and may rub it back and forth to get the right view. This imaging technique works in a manner similar to radar and sonar, developed in World War II to detect airplanes, missiles, and submarines that were otherwise invisible. Ultrasound uses sound waves instead of radiation to generate snapshots or moving pictures of structures inside the body.
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