Doppler ultrasound is a technique used to measure the flow
of blood through your arteries and blood vessels—usually those in your
extremities. Vascular flow studies, also known as blood flow studies, can
detect abnormal flow within a blood vessel. This can help to diagnose and treat
a variety of conditions, including blood clots and poor circulation. A Doppler
ultrasound can be used as part of a blood flow study.
This risk-free and pain-free
procedure requires little preparation and can provide your doctor with valuable
information about your blood pressure and any arterial blockages you may have.
Why Do I Need a Doppler Ultrasound?
You doctor may
suggest a Doppler ultrasound exam if you show signs of decreased blood flow in
the arteries or veins of your legs, arms, or neck. This may be due to an arterial
blockage, a blood clot inside a blood vessel or bypass graft, or an injury to a
ultrasound exam may be ordered if you have (or if your doctor thinks you may
- deep vein
thrombosis (a blood clot in a vein deep inside your body)
thrombophlebitis (inflammation due to a blood clot in a vein just below the
of the extremities (narrowing and hardening of the arteries that supply blood
to the legs and feet)
obliterans (a rare disease in which the blood vessels of the hands and feet
tumors in your arms or legs
ultrasound will be able to measure the blood flow through the arteries or veins
in question. The test can show how much blood flows through your arteries with
each heartbeat as well as the blood pressure within your arteries.
How Should I Prepare for a Blood Flow Study?
preparation is required for this test. However, if you are a smoker, your
physician may ask you to stop smoking for several hours before the test because
smoking causes your blood vessels to constrict.
What Happens During the Procedure?
This is a
noninvasive, painless procedure that will not expose you to harmful radiation.
There are no risks associated with this test, and most people feel little or no
discomfort during or after the procedure.
The test is usually
performed in the radiology department of a hospital, doctor's office, or
peripheral vascular lab. The procedure can vary slightly, depending on the
doctor, technician, and hospital. In general, you can expect the following:
will need to remove clothing, jewelry, and any other objects from the area to
be studied. You may be asked to wear a hospital gown. There is no need to
remove your glasses, contact lenses, dentures, or hearing aids.
procedure will take place with you lying on an examination table or bed.
examine your veins, a water-soluble gel will be placed on a handheld device
called a transducer (similar to a microphone), which directs high-frequency
sound waves into the arteries or veins being studied.
examine your arteries, blood pressure cuffs may be placed around different
parts of your body, including your thigh, calf, ankle, and various points along
are created as the transducer is pressed against your skin and moved along your
arm or leg. The transducer sends sound waves through your skin and other body
tissues to the blood vessels. The sound waves echo off your blood vessels and
send the information to a monitor to be processed and recorded. The transducer
will be moved to different areas for comparison. You may hear a
"whooshing" sound as blood flow is detected
Doppler Ultrasound Exam of Leg Arteries
When examining your leg arteries, your doctor will look for
narrowing of the blood vessels that may cause you pain when walking or resting,
skin discoloration, or ulcers of the foot, ankle, heel, or toe.
procedure, blood pressure cuffs will be placed in several positions on your
leg. This is to help compare the blood pressure in different parts of your leg.
The cuffs will generally be applied to the thigh, calf, and ankle. Your blood
pressure will also be taken on the arm on the same side of your body as the leg
Your exam will be
completed in about an hour. Depending on your signs and symptoms, you may be
asked to perform some mild exercises after the exam.
After the Procedure
For most people,
there are no special instructions following the procedure. Unless advised
differently by your doctor, you may resume your usual activities right away.
Interpreting the Test Results
Normal test results
indicate that you have no narrowing
or blockages in your arteries and that the blood pressure in your arteries is
normal. Abnormal blood flow
patterns, including narrowing or closure of the arteries, can indicate:
in the arteries (sometimes due to cholesterol buildup)
clot(s) in a vein or artery
circulation (can be related to blood vessel damage from chronic conditions,
such as diabetes)
occlusion (closing of a vein)
or clots in an artificial bypass graft
are some factors that may compromise the results and require a repeat of the
test or other additional testing. These include:
less than one hour before the test (smoking causes your blood vessels to
dysrhythmias/arrhythmias (irregular heart rhythms)
The test results
will be sent to your doctor. If abnormalities are found, your doctor will
discuss any additional tests or treatments with you.