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.
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.
For a transcranial
ultrasound, the transducer is passed lightly over the skin at the base or side
of your skull.
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
There are no known risks linked with a
Doppler ultrasound test. This test will not harm a developing baby (fetus).
ultrasound test uses reflected sound waves to see how
blood flows through a blood vessel.
There are no findings of
significant narrowing or other abnormality in any of the arteries
There is no evidence of a clot
in any of the veins examined. The size and position of veins are
Normal blood flow is found in
the blood vessels that supply oxygen and nutrients to a
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
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
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