A Doppler ultrasound of the carotid arteries in the neck is a diagnostic procedure that produces images of the vessels' blood flow, RadiologyInfo states. This noninvasive technique uses frequency fluctuations to monitor the speed and directional movement of blood cells, allowing physicians to view real-time renderings of blood circulation.
During the ultrasound, the radiologist uses handheld equipment, known as a transducer, to send sound waves toward the target arteries and record their pitch as the waves are reflected back, WebMD notes. As blood cells move, the sound waves bounce off of them at different pitches, creating changes in frequency results. Based on this phenomenon, known as the Doppler effect, radiologists can quickly locate abnormalities because the pitch does not fluctuate when blood flow stops. Ultrasounds of the neck are usually performed with the patient lying down, and the radiologist tests arteries on both sides of the body to help prepare a comparison of healthy and abnormal diagnostic results. Doppler ultrasounds do not involve radiation and are considered risk-free for pregnant women and babies.
The Doppler ultrasound is usually a specialized segment of a larger ultrasound process when examining the carotid artery for unhealthy constriction and blockage or when a physician detects abnormal sounds through a stethoscope, according to RadiologyInfo. This diagnostic technique is commonly used for locating blood clots and tumors, monitoring cardiac stents, and evaluating stroke or cholesterol risks.