Have you been referred for Doppler ultrasound but you don’t quite know what it is? Here’s a short explainer.

Doppler ultrasound is a non-invasive test used to measure the blood flow in your blood vessels. It works by bouncing high-frequency sound waves off the red blood cells circulating in the bloodstream. It detects changes in the frequency of the sound waves as they bounce off moving red blood cells. This is called the Doppler shift.

A regular ultrasound uses sound waves to produce images but can’t show blood flow.

Why do you undergo Doppler ultrasound?

A Doppler test is performed by a technician trained in ultrasound examinations and the procedure is used to assess various conditions:

• Blocked or narrowed arteries (e.g., carotid artery disease)
• Poor circulation or blood flow problems (e.g., deep vein thrombosis)

What to remember

• Preparations for a Doppler ultrasound depend on which part of your body is being examined. Your healthcare provider will brief you on preparations, as you may need to fast (not eat or drink) for several hours before the test.
• The test is non-invasive and painless.
• It uses sound waves, so it does not involve radiation (unlike X-rays or CT scans).
• The test may take between 30 minutes to an hour, depending on the area being examined.

What to expect during a Doppler ultrasound

• You may be asked to lie down on an examination table.
• A gel is applied to the area being examined to help the sound wave transmission.
• A small device called a transducer is moved onto your skin, which emits sound waves and picks up the reflection.
• You may hear some pulsing sounds that correspond to the blood flow as it is measured.

Results of a Doppler ultrasound test

The results can provide a lot of information about the flow of blood in your blood vessels or heart. A radiologist will create a report that will be sent to your doctor.

The Doppler test results are then typically reviewed by your doctor, who will provide an explanation of what the findings mean in the context of your health condition. These results may be used to guide further diagnostic tests or treatment plans including medications, lifestyle changes, or procedures.

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• This article is part of a series aimed at decoding radiology jargon for patients. Visit our news section for more.
• The article is intended to create awareness and none of the information it contains should replace the need for seeking personal advice from a qualified medical practitioner.
• Apart from selected screening examinations, all radiology procedures are performed upon referral from a qualified medical professional.