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Ultrasound / Ultrasonography

	Why color doppler procedure is necessary?		How to prepare for color doppler procedure?
	How color doppler is done?		What are the negative aspect of the study?
	What about the results?		What affect the color doppler procedure?
	What to think about?		Who interprets the results and how do I get them?

Why color doppler procedure is necessary?

Doppler ultrasound is done to:
Detect blood clots and blocked or narrowed blood vessels in almost any part of the body, especially in the neck, arms, and legs. Blocked or narrowed arteries of the neck can cause dizziness, loss of vision, paralysis, weakness, numbness, or other symptoms of a stroke. Blood clots in the deep veins of the leg can cause leg pain and swelling and can increase a person's risk of pulmonary embolism.

Evaluate leg pain that may be caused by intermittent claudication, a condition caused by atherosclerosis of the lower extremities.
Evaluate blood flow after a stroke or other condition that might be caused by a problem with blood flow. Evaluation of a stroke can be done through a technique called transcranial Doppler (TCD) ultrasound.
Map veins that may be used for blood vessel grafts. It also can evaluate the condition of grafts used to bypass blockage in an arm or leg.
Determine the amount of blood flow to a transplanted kidney or liver.
Monitor the flow of blood following blood vessel surgery.
Determine the presence, amount, and location of arterial plaque. Plaque in the carotid arteries can reduce blood flow to the brain and may increase the risk of stroke.
A transcranial Doppler ultrasound (TCD) may be used in children with sickle cell disease to evaluate their risk of stroke. In adults, it can be used to evaluate blood flow and vessel spasms in the brain.

How to prepare for color doppler procedure?

You may be asked to avoid products that contain nicotine (cigarettes, chewing tobacco) for 30 minutes to 2 hours before the test. Nicotine causes blood vessels to constrict and may give false results.

How color doppler is done?

This test is done by a doctor who specializes in performing and interpreting imaging tests (radiologist) or by an ultrasound technologist (sonographer). It is done in an ultrasound room in a hospital or doctor's office.

You will need to remove any jewelry that might interfere with the Doppler ultrasound scan. You may need to take off all or most of your clothes, depending on which area is being examined (you may be allowed to keep on your underwear if it does not interfere with the test). You will be given a cloth or paper covering to use during the test.

For abdominal scans, you will lie on your back.

For chest scans, you will lie on your back with your neck slightly extended.

For head and neck scans, your head may be turned to one side.

For an arm or leg scan, your head is slightly raised and the exposed arm or leg is turned slightly outward. Occasionally for a leg scan, you may be asked to lie on your stomach.

Gel is applied to the skin to promote the passage of the sound waves. The transducer is placed in the gel and moved along the skin. You need to lie very still during the procedure. You may hear sounds that represent the flow of blood through the blood vessels.

The test usually takes 30 to 60 minutes.

Arteries in the arms and legs :

This test is often performed on both arms or both legs. Even if the suspected blood flow problem is in only one limb, both may be tested for comparison. If your arms are being tested, they will be tested first while you are lying down and then again while you are sitting.

Depending on which blood vessels are being tested, a blood pressure cuff may be wrapped around one or both limbs so that the blood pressure can be taken at several different places. When testing the legs, a blood pressure cuff may be wrapped first around the calf and then around the thigh. The test may be done at several locations on your leg. When testing the arms, the pressure cuff may be wrapped first around the forearm and then around the upper arm.

Veins in the arms and legs

For this test, you will be asked to lie down and breathe normally. You must lie very still. Any changes in blood flow that occur as a response to your breathing patterns are noted.

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 Valsalva's 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.

How It Feels

There is normally no discomfort involved with having a Doppler ultrasound test. The gel may feel cold when it is applied to 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 cuffs are inflated.

What are the negative aspect of the study?

There are no known risks associated with a Doppler ultrasound test.

What about the results?

A Doppler ultrasound test uses reflected sound waves to evaluate blood as it 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 clot in any of the veins examined.

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), aneurysm, or narrowing of a blood vessel may be detected. The speed of blood flow may be compared to standard values to determine the amount of blockage or narrowing of the blood vessel.

A duplex Doppler ultrasound graph may show irregular flow that indicates 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 a compression maneuver or Valsalva's maneuver. Incomplete blockage of a vein by a blood clot may be seen on color Doppler or during a compression maneuver.

What affect the color doppler procedure?

Factors that can interfere with your test and the accuracy of the results include:

Bones above the area being studied or gas in the intestines.
The inability to remain still during the test.
Extreme obesity.
Irregular heart rhythms (arrhythmias) or heart disease, which may cause changes in blood flow patterns even though the blood vessels are not abnormal.
Having a cold arm or leg. Blood flow through that limb may be slowed.
Having an open wound in the area that needs to be viewed.

What to think about?

Producing accurate test results with Doppler ultrasound requires a skilled examiner. The scans are usually read within a short period of time in case repeat tests are needed.

Because Doppler ultrasound requires a person to hold very still, some children may need to be sedated so that their movements do not interfere with the results.

Angiography and venography are X-ray tests that require the injection of contrast material. In many cases, Doppler ultrasound may be done instead of angiography or venography, since it is faster, less expensive, and noninvasive. If results from a Doppler ultrasound are inconclusive, an angiography or venography test may be done. Angiography is usually more accurate than Doppler ultrasound and is considered the most definitive test for evaluating blood flow through an artery. Magnetic resonance angiography (MRA) and computed tomography (CT) angiography may be done instead of conventional angiography because these tests are less invasive and easier to perform than conventional angiography. In some cases, venography may be needed to confirm a suspected vein problem. For more information, see the medical tests Angiogram, Venogram, and Magnetic Resonance Angiogram (MRA).

Who interprets the results and how do I get them?

Your colour doppler examination is interpreted by a panel of highly qualified and experienced radiologists (see our doctors). After your visit for a diagnostic imaging procedure, the images from your exam are transferred to one of our radiologists who specializes in analyzing images of the specific area of the body you had examined. Next, the radiologist prepares a diagnostic report to share with the doctor that sent you to us. We retains exam films and reports electronically for a set length of time. Please contact our reception counter after your diagnostic imaging procedure if you have questions regarding the timings (Usually available within few hours unless emergency case) and procedure for collecting the reports or next steps or follow-up appointments. New technology also allows us for distribution of diagnostic reports and referral images over the Internet at many facilities. Our radiologists have established themselves as valued consultants and colleagues with our referring physicians. They are available 24X7 days for emergency interpretations. They pride themselves on being accessible and responsive.

A Doppler ultrasound may be used to evaluate many body organs. It can also be used safely during pregnancy.


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