Doppler is a term that refers to the Doppler effect, which is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. In medical imaging, Doppler ultrasound is a noninvasive test that uses sound waves to estimate the blood flow through blood vessels by bouncing high-frequency sound waves off circulating red blood cells. The test can be used to examine the heart, check blood flow in veins, arteries, and heart, and diagnose or help manage conditions that reduce or block blood flow.

Doppler ultrasound works by measuring sound waves that are reflected from moving objects, such as red blood cells. The frequency shift of each pulse is used to obtain the frequency shift, and the relative phase changes of the pulses are used to obtain distance information. There are different types of Doppler ultrasound tests, including color Doppler, spectral Doppler, and duplex Doppler.

Color Doppler uses a computer to change sound waves into different colors to show the direction of blood flow in real-time. Spectral Doppler provides a graphical representation of blood flow over time, while duplex Doppler combines traditional ultrasound pictures with Doppler ultrasound to check the width of blood vessels and help show blockages.

During a Doppler ultrasound, a sonographer, a specialist in ultrasound imaging technology, performs the test. The test may take 30 to 60 minutes, and depending on the reason for the test, the patient may lie on their back or side on an exam table, or they may sit up. The sonographer applies a small amount of gel to the patients skin, which helps the sound waves travel, and then glides a small probe over the skin.

Doppler ultrasound is a safe, painless way for healthcare providers to assess the health of blood vessels and check for cardiovascular problems. The test is very effective in many cases, but its not good at finding clots in the pelvis or the small blood vessels in the calf. The results of the test are available right away for the doctor to review, and the test is very safe, painless, and doesnt use radiation.