Different Types & Importance of Doppler Ultrasound Tests

Submitted on March 27, 2012

What is a Doppler Ultrasound?

Doppler ultrasound is a non-invasive medical test that measures blood flow and pressure using high frequency sound waves. As these sound waves pass through the blood vessels, doctors are able to capture images that helps estimate the speed and measure of blood flow in the major arteries and veins in the body.

Using this technology doctors are able to evaluate the flow of blood through the major arteries and veins in the body (especially the in the neck, arms and leg); this in turn helps them zero in on blocked arteries, narrowing arteries, blood clots in the veins, or reduced blood flow to a particular region - all potentially fatal occurrences; undetected these lead to strokes, or heart failures.

Types of Doppler Ultrasound Tests

There are different types of Doppler ultrasound tests; these include color Doppler ultrasound, pulsed Doppler ultrasound, and power Doppler ultrasound.

Importance of Doppler Ultrasound Examination

A Doppler ultrasound examination helps track blood flow through the blood vessels as well as detects abnormalities in blood flow.

It is an important test to determine the following:

  • A Doppler ultrasound helps detect blockages and narrowed blood vessels in the body. These are known to cause dizziness, numbness, paralysis, increasing the chances of a stroke.
  • A carotid Doppler ultrasound test is used to measure blood flow through the large carotid arteries that transport blood to the brain. If these grow narrow they can cause a stroke.
  • The test helps evaluate blood clotting in the veins. This usually occurs in the legs causing varicose veins and other related problems. Not only is the condition painful, it can also lead to a pulmonary embolism.
  • Using a transcranial Doppler ultrasound (TCD) test doctors study blood flow in patients who have suffered stroke. This helps to evaluate the patient’s condition and chart a treatment plan. It is also used to monitor blood flow in children with sickle cell disease.
  • A Doppler ultrasound test is also used by doctors to monitor blood flow after organ transplant (used widely after kidney and liver transplants).
  • During pregnancy Doppler Ultrasound is used to monitor the blood flow of the unborn baby.


During a Doppler ultrasound test, an instrument called a transducer is passed over the skin where the targeted blood vessel is located. This instrument sends and receives sound waves through the blood vessels. As the blood flows, the movement causes changes in the pitch of the reflected waves - this is called the Doppler Effect. This information is gathered from the sound waves and processed on a computer. The procedure takes from 30-60 minutes.