Doppler Ultrasound

What Is a Doppler Ultrasound?

Doppler Ultrasound is a non-invasive diagnostic method to study the manner of blood flow and circulation in the body, to ascertain the presence of clots and blockages in veins and arteries.

Doppler ultrasound is the most effective diagnostic test to check for a medical condition called Deep Vein Thrombosis. The Doppler ultrasound employs reflected sound waves to:

– Ascertain how blood circulates through important arteries and veins, for instance in the neck, arms, and legs. It can show blocked or reduced flow of blood through narrow areas in the major arteries of the neck that could potentially cause a stroke.

– It can also reveal blood clots in leg veins (deep vein thrombosis,) that could break loose and block blood flow to the lungs, medically called pulmonary embolism

– A Doppler ultrasound can evaluate blood circulation in organs of the body. It can also be done safely during pregnancy.

How does a Doppler ultrasound work?

A transducer, which is a hand-held instrument, conveys sound waves when it is held on the skin on a top of a blood vessel. The sound waves get amplified with the help of a microphone. An alteration in the pitch of the reflected sound waves (caused by the blood flow), creates a Doppler effect.

What is important is, the pitch does not show any changes when there is no blood flow. The information thus collected by the sound waves produced on a computer as images and graphs that depict the manner of blood circulation.

Doppler test involves the use of four types of ultrasound such as the color doppler, duplex Doppler and continuous wave doppler or bedside Doppler.

Why should I undergo a doppler ultrasound?

Certain symptoms may need to be investigated for instance, if you have constant pain or swelling in your legs. Doppler ultrasound can detect the nature of blood flow and can spot places where blood flow is reduced. These increase the chances of a clot. A doppler ultrasound is useful for the following reasons.

– It can easily locate constricted or blocked blood vessels in arms, legs, and neck.

– Find the reason for leg pain.

– Evaluate blood flow to liver or kidney post-transplantation or after surgery to the blood vessels.

– Can gauge the extent of arterial plaque.

– It can help in directing laser treatment ablation of problematic veins.

– To check fetal health and the amount of oxygen and nutrients during pregnancy.

– Ascertain blood flow to heart, arteries, and veins.

– Check for an aneurysm.

– To check for blood flow in the spleen, liver, pancreas, and kidneys.

How do I prepare for this test?

– Wear comfortable clothes.

– Ensure you do not smoke or chew nicotine products for at least 2 hours before the test. The results may not be accurate as nicotine causes blood vessels to narrow.

– Remove all your jewelry and accessories before the test.

– Specific instruction for those getting a pelvic Doppler ultrasound is to ensure the bladder is full for an accurate test. You need to drink water one hour before the schedule of the ultrasound.

Do I need to fast before a Doppler ultrasound?

If you are to undergo a belly doppler ultrasound, you need to be on an empty stomach for at least 6 to 12 hours before the schedule of the test.

What is the procedure followed for a Doppler ultrasound?

The Doppler ultrasound is usually performed in a doctor’s office or even at a hospital in a designated room. It is performed by a doctor who is a specialist in imaging tests or by an ultrasound technologist, also called a sonographer. It may take anywhere from 30 to 60 minutes to do the test.

You need to lie on the ultrasound table.

The position on the table will depend on the area which needs to be scanned.

You may be asked to lie on your back for an abdominal scan.

It is important to breathe normally and lie still without unnecessary movements.

For a chest ultrasound, the position is the same, except you, may have to extend the neck. Head and neck need to be turned to a side for a scan of the neck and head.

Pregnant women need to lie on the back and turn to the left side exposing the belly.

A gel is applied to the skin to help convey sound waves. The transducer is placed on the gel and movements are madeon the skin.

A gel is applied by the technician on the area to be scanned. The gel helps in better results asit aids the communication of sound waves.

A handheld device is now pressedagainst your skin. A computer now transforms all the sound waves into imageswhich are relayed live on the screen.

For a transcranial ultrasound, the transducer is placed on the skinat the side or base of the skull.

A blood pressure cuff may also be attached depending on what blood vessels are being scanned to record the pressure at several places of the arms and legs.

After the test, the gel is wiped off and the test is completed.

You can go home after the test is done and can resume your normal activities.

When will I get the results of Doppler ultrasound?

The results of a Doppler ultrasound should be available very soon.  The images are ready almost immediately following the test. The radiologist makes a study of the pictures and writes the report. The images may be given as a CD or it could be in a film.

What do the results mean?

If your result is normal it means there is no major narrowing or any other issue detected in the investigated arteries. It means the veins are healthy with no clots and are of normal size and position.

The doctor usually discusses with you what the images mean.  If the scan was performed to evaluate DVT, the pictures depict how the blood flow is and basis the result, you will be advised what guidelines to follow.

In case a clot was found, you may need to undergo another doppler ultrasound in the next few days to see the progression of the clot or the development of fresh ones.

Are there reasons why a Doppler ultrasound cannot be performed?

The presence of certain medical conditions or patients’ responses can be a deterrent to performing this test. Some of the instances are detailed below:
– Too many movements during the test or inability to be still.
– Intestinal gas.
– Injury and an open wound in the area that needs to be studied.

What are some of the overriding benefits of a Doppler ultrasound?

Key benefits of a Doppler ultrasound are:

– Radiation free.
– Non-invasive.
– Less expensive compared to some invasive techniques.
– Depicts the amount and speed of blood flow.
– It can be done in place of venography or angiography.

What are the known risks of Doppler ultrasound?

No significant risks have been reported yet with the use of Doppler ultrasound.

Is a Doppler ultrasound the same as a regular ultrasound?

A Doppler ultrasound employs sound waves of very high frequency to evaluate blood flow in the blood vessels. A regular ultrasound also employs sound waves but is not equipped to demonstrate the blood flow. Doppler ultrasound is a sure shot way to diagnose DVT or deep vein thrombosis.

Is the procedure painful?

Patients do not experience any pain during the test.

Is there a risk of radiation using Doppler ultrasound?

There is no risk of radiation using the Doppler ultrasound.

What is deep vein thrombosis?

This is a medical condition that leads to the formation of blood clots in the veins of the body. The clots are formed usually in the legs. It can be life-threatening if the clot travels to the lungs leading to pulmonary embolism.

What is the price of Doppler ultrasound in India?

The price of Doppler Ultrasound in India can vary from Rs. 1500 to Rs 4000, depending on the type of doppler test required and also the city and the type of healthcare facilities available.

Is Doppler ultrasound safe for children?

Children suffering from sickle cell disease are asked to undergo a transcranial ultrasound (TCD) to investigate their risk of stroke. Children need to be sedated prior to the procedure as they may not be still during the procedure. It is safe for children.

Is Doppler ultrasound used in pregnancy?

Doppler ultrasound is extremely helpful during pregnancy as it helps study blood circulation in the fetus as well as the placenta and uterus.

– It is especially beneficial in high-risk pregnancies. The results of a Doppler ultrasound help in the decision in making during this period.

– In certain cases, the fetus is smaller as compared to what it should ideally be for the gestational age. A Doppler ultrasound can check how the blood flow is to the umbilical artery, and understand the reason for deficient growth.

– Doctors also evaluate the blood flow through MCA or the middle cerebral artery in the brain to evaluate the health of the fetus.

– If the expectant mother has other complications during the pregnancy such as preeclampsia, a doppler ultrasound helps in checking blood circulation.