artery doppler ultrasound
test uses a technique called Doppler ultrasound to measure blood
flow through the carotid arteries inside the neck, which supply
blood to the brain. A device called a transducer is passed lightly
over the neck, directing high-frequency sound waves (ultrasound)
into the carotid arteries. The sound waves are reflected back
at frequencies that correspond to the velocity of blood flow,
and are converted into audible sounds and graphic recordings.
combines Doppler ultrasound with real-time ultrasound imaging
of the carotid arteries, allowing calculation of the percent
of narrowing in the vessels. Images are displayed on a viewing
monitor and may also be recorded on film or video for later examination.
Purpose of the Test
To assess blood
flow in the carotid arteries and detect any blockages, such as
clots or atherosclerosis (narrowing due to the buildup of plaques).
Who Performs It
A doctor or
a technician who is trained in ultrasound.
Before the Test
preparation is necessary.
What You Experience
You will lie
on your back on an examination table, and your head will be supported
to inhibit movement.
gel is applied to the skin on your neck to enhance sound wave
then moves the transducer back and forth over one side of your
neck to obtain different views of the carotid artery. The other
side of your neck is then checked in the same way.
images of the carotid artery are obtained, they are recorded
on film or video for later analysis.
The test takes
about 15 to 30 minutes.
Risks and Complications
is painless, noninvasive, and involves no exposure to radiation.
There are no associated risks.
After the Test
removes the conductive gel from your skin.
You may resume
your normal activities.
reviews the recorded images and other test data for evidence
of abnormalities. High blood flow velocity indicates narrowing
of the carotid arteries.
If the carotid
arteries are blocked, appropriate therapy will be initiated to
reduce your risk of stroke.
In some casesespecially
if surgery to remove carotid blockages is contemplatedadditional
diagnostic tests, such as arteriography, may be ordered to determine
the exact location and extent of the occlusive plaques.
From The Johns
Hopkins Consumer Guide to Medical Tests. You can order
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