Skip to content

    Deep Vein Thrombosis Health Center

    Font Size

    Doppler Ultrasound


    There are no known risks linked with a Doppler ultrasound test. This test will not harm a developing baby (fetus).


    A Doppler ultrasound test uses reflected sound waves to see how blood flows through a blood vessel.

    Doppler ultrasound

    There are no findings of significant narrowing or other abnormality in any of the arteries examined.

    There is no evidence of a clot in any of the veins examined. The size and position of veins are normal.

    Normal blood flow is found in the blood vessels that supply oxygen and nutrients to a fetus.


    For continuous wave Doppler or duplex Doppler, differences in blood flow between the right and left sides of the body may be heard. At the exact location where an artery is blocked or narrowed, the sound may be high-pitched or turbulent. Blockage (such as from a blood clot), an aneurysm, or narrowing of a blood vessel may be detected. The speed of blood flow may be compared to standard values to find out the amount of blockage or narrowing of the blood vessel.

    A duplex Doppler ultrasound graph may show irregular flow that means a blocked or narrowed blood vessel.

    A color Doppler image may show a blocked or narrowed blood vessel or an aneurysm.

    In the veins, a blood clot may be indicated if blood flow does not change in response to breathing or does not increase in response to either a compression maneuver or Valsalva maneuver. Incomplete blockage of a vein by a blood clot may be seen on color Doppler or during a compression maneuver.

    Abnormal veins, such as varicose veins, are seen.

    Blood flow through the blood vessels that supply oxygen and nutrients to a fetus is abnormally increased or decreased.

    What Affects the Test

    Reasons you may not be able to have the test or why the results may not be helpful include:

    • Bones above the area being studied or gas in the intestines, which may interfere with the pictures.
    • Not being able to remain still during the test.
    • Extreme obesity.
    • Irregular heart rhythms (arrhythmias) or heart disease, which may cause changes in blood flow patterns even though the blood vessels are not abnormal.
    • Having a cold arm or leg. Blood flow through that limb may be slowed.
    • Having an open wound in the area that needs to be viewed.

    WebMD Medical Reference from Healthwise

    Last Updated: September 09, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

    Today on WebMD

    TAG dvt blood clot
    Symptoms, causes, risk factors, and more.
    businesswoman in airport
    Tips to prevent another clot.
    blood thinners
    Tips for DVT.
    Blood clots in artery
    Causes and treatments.
    Simple Steps to Lower Cholesterol
    Having Surgery Tips To Reduce DVT Risk And More
    New DVT Therapies On The Horizon
    Atrial Fibrillation Guide

    WebMD Special Sections