Before the procedure
Wear a comfortable shirt with no collar or an open collar. Don't wear a necklace or dangling earrings.
Unless your doctor or the radiology lab provides special instructions, you shouldn't need to make any other preparations.
How it works
A technician (sonographer) conducts the test with a small, hand-held device called a transducer. The transducer emits sound waves and records the echo as the waves bounce off tissues and blood cells.
A computer translates the echoed sound waves into a live-action image on a monitor. If a Doppler ultrasound is performed, the information about the rate of blood flow is translated into a graph.
A carotid ultrasound usually takes about 30 minutes.
During the procedure
You'll likely lie down on your back during the procedure. The ultrasound technician (sonographer) may gently adjust the position of your head to improve access to the side of your neck. The sonographer will apply a warm gel to your skin above the site of each carotid artery. The gel helps eliminate the formation of air pockets between your skin and the transducer. The sonographer then gently presses the transducer against the side of your neck in order for the instrument to send and receive sound waves.
You shouldn't feel any discomfort during the procedure. If you do, tell the sonographer.