Doppler ultrasound scan of the legs: how it is carried out and what it is used for
A leg Doppler scan is an ultrasound scan that shows the veins and arteries and how blood flows through them. It is used to diagnose varicose veins, blood clots and poor circulation. It is painless, involves no needles or radiation, and takes around 20 minutes. At Allure Clinic, it is carried out by the vascular surgeon during the consultation, and the results are explained on the same day.
What is the purpose of the Doppler ultrasound on the legs?
The Doppler ultrasound exam is indicated to evaluate the structure of blood vessels (size, presence of obstructions or lesions) and their flow. Using high-frequency sound waves (ultrasound), it determines the speed and direction of blood in the body.
This examination constitutes the appropriate auxiliary diagnostic means to identify:
- Blood clots;
- Malfunctioning valves in the veins of the legs (venous insufficiency);
- Heart valve defects and congenital heart disease;
- Blocked arteries (arterial occlusion);
- Deep vein thrombosis;
- Superficial venous thrombosis;
- Decreased blood circulation in the legs (peripheral arterial disease);
- Bulging arteries (limb aneurysms);
- Narrowing of an artery (artery stenosis).
It can also be used to check the effects of an intervention, for periodic monitoring or therapeutic planning of pathologies that can cause a stroke.
It's an important observation tool for ruling out the presence of thrombi in the leg veins, ruling out an alternative diagnosis. It's also essential for guiding procedures in vascular surgeries.
What types of Doppler ultrasound exams on the legs are there?
To assess blood flow in the lower limbs, there are two types of Doppler ultrasound: venous and arterial.
Venous Doppler ultrasound of the lower limbs
It is indicated in cases of suspected deep vein thrombosis, when there is partial or total obstruction of a vein in the deep venous system.
In addition to accurately assessing whether there is a thrombus in the blood vessel, it allows you to determine whether it is recent, old, or if there are vascular complications.
This examination is also performed in cases of varicose veins or other symptoms of chronic venous insufficiency in the lower limbs, such as: swelling, red or scaly skin.
Arterial Doppler ultrasound of the lower limbs
It analyzes arterial changes in the lower limbs, such as the presence of atheromatous plaques, vascular calcifications, or peripheral arterial disease (PAD). It is essential in the diagnosis of patients with atypical symptoms.
It allows the assessment of blood circulation in patients with cardiovascular risk factors, undergoing arterial revascularization of the lower limbs or with suspected iatrogenic injury after arterial catheterization.
It is also indicated to determine the severity of arterial disease, helping to define the healing potential of ulcers.
What are the advantages of Doppler ultrasound on the legs?
When compared to other diagnostic tests, such as Computerized Tomography (CT) or Magnetic Resonance Imaging (MRI), Doppler Ultrasound offers many advantages, including:
- Painless and non-invasive examination;
- No known side effects;
- No needles are used;
- No ionizing radiation is used;
- It is safe for adults, children, elderly or pregnant women;
- No preparation needed;
- Does not require rest after the exam;
- It's quick (about 20 minutes);
- More economical than computed tomography (CT);
- More economical than magnetic resonance imaging (MRI).
How is the Doppler ultrasound exam performed on the lower limbs?
The test is carried out at the doctor’s surgery and takes around 20 minutes; no special preparation is required: you do not need to fast or stop taking your usual medication.
- The doctor asks about the symptoms and the reason for the examination.
- Put on a lab coat and remove any jewellery or accessories from the area under observation.
- To examine the veins, the test is carried out whilst standing. For the arteries, it can be carried out whilst lying down and, sometimes, with blood pressure cuffs placed at various points on the legs.
- The doctor applies a gel to the skin and moves the ultrasound probe along the leg, applying gentle pressure.
- The screen displays images of the blood vessels, as well as the speed and direction of the blood.
- At the end, the doctor explains the results and, if necessary, the treatment.
You may feel the cool gel and some pressure from the probe, but the examination does not hurt. You can resume your normal activities straight away.
How much does an Eco Doppler exam cost?
You can request prior information about the price of the Doppler ultrasound examination on the lower limbs.
The Doppler ultrasound scan is carried out at the Vascular Surgery clinic at Allure Clinic in Porto.
Frequently asked questions about the colour Doppler ultrasound
Are Doppler, Doppler ultrasound and ultrasound the same thing?
Eco-Doppler combines two things: ultrasound, which produces an image of the blood vessels, and Doppler, which measures the speed and direction of the blood. When people refer to a "Doppler scan of the legs", they are usually talking about this test.
Does an echo-Doppler scan hurt?
No. You’ll just feel the gel and a slight pressure from the probe on your skin.
Do I need to fast beforehand?
No. You do not need to fast or take any other preparatory measures for a leg Doppler ultrasound. It is a good idea to bring clothing that is easy to take off and any previous test results, if you have them.
Can I have the test whilst I’m pregnant?
Yes. The colour Doppler uses ultrasound waves rather than radiation, so it is safe during pregnancy.
How long does it take?
Around 20 minutes, although it may take longer if the veins and arteries in both legs are examined.
When will I find out the result?
During the consultation itself. The doctor explains what she has seen and, if necessary, suggests a course of treatment.
Sources:
Dr. Joana de Carvalho
- Graduated from the Faculty of Medicine of the University of Porto
- Specialist in Angiology and Vascular Surgery
- Fellow of the European Board of Vascular Surgery
- Member of the College of Phlebology
English (UK)