Carotid Doppler Ultrasound

Carotid Doppler Ultrasound

What is it?

A standard carotid ultrasound shows the structure of the carotid arteries. Doppler ultrasound is a special test that shows movement of the blood through the vessels. A doctor will use both to assess whether there is a problem with blood flow through the carotid arteries in the neck.

They are both non-invasive, which means no needles, dyes, radiation or anesthesia are used.

How does it work?

During a carotid ultrasound, sound waves are transmitted through the tissues of the area being examined. These sound waves reflect off blood cells moving within the blood vessels, allowing the reading physician to calculate their speed. The sound waves are recorded and displayed on a computer screen.

Doppler ultrasound is a special application of ultrasound which measures the direction and speed of blood cells as they move through vessels. The movement of blood cells causes a change in pitch of the reflected sound waves (called the Doppler Effect). A computer collects and processes the sounds and creates graphs or color pictures that represent the flow of blood through the blood vessels.

Reasons for a Carotid Doppler Ultrasound

The carotid Doppler ultrasound is most frequently performed to detect narrowing (stenosis) of the carotid artery which substantially increases the risk of a stroke. It may also be performed if a patient has high blood pressure or an abnormal sound in the neck heard through a stethoscope. Other reasons this diagnostic test may be performed are:

  • Detect dissection of the carotid artery
  • Confirm the blood flow through a carotid stent
  • Check the state of the carotid artery after surgery
  • Locate a blood clot (hematoma)
  • Tumors
  • Congenital abnormalities

Or if patients have the following:

  • Diabetes
  • Advanced age
  • Elevated blood cholesterol
  • Family history of stroke or heart disease

What to expect

The entire test takes 30 to 90 minutes to complete and there is no discomfort, nor are there any side effects of the test. The patient will lie on an examination table. A technician will apply a water-soluble gel over the area to be examined. An instrument (transducer) is placed over the gel-coated area to produce images on the ultrasound screen. Doppler ultrasound uses this same transducer which is held in place until the blood flow information is recorded.

St. Luke's Heart & Vascular