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Doppler Ultrasound

How It Is Done continued...

The test may be repeated while the examiner presses on the veins close to the surface of your skin to help detect a clot in the vein (called a compression maneuver). The examiner may do this with your legs or arms in different positions to ensure that the blood supply is not blocked in these positions. The examiner may also squeeze your calf or forearm to help blood move more quickly through the veins (called an augmentation maneuver). This is done to evaluate blood flow toward your heart.

While your legs are being tested, you may also be asked to try to breathe out strongly with your nose pinched and your mouth closed (called a Valsalva maneuver). This maneuver usually causes a sudden change in blood flow through the veins.

Arteries in the neck

You will be asked to lie down with a pillow underneath your head for support. The test is performed on both sides of your neck, and then the results are compared to standard values to determine the amount of blockage or narrowing of the arteries.

Transcranial ultrasound

For a transcranial ultrasound, the transducer is passed lightly over the skin at the base or side of your skull.

During pregnancy

The transducer is moved back and forth on your belly until the doctor finds the blood vessel that needs to be studied. After the doctor has found the blood vessel, it may take some time to check the blood flow.

How It Feels

There is normally no discomfort involved with having a Doppler ultrasound test. The gel may feel cold when it is put on your skin unless it is first warmed to body temperature. If your blood pressure is taken during the test, you will feel pressure when the blood pressure cuff is inflated.

Risks

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

Results

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

Doppler ultrasound
Normal:

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.

Abnormal:

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.

WebMD Medical Reference from Healthwise

Last Updated: November 29, 2012
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.

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