Doppler ultrasound: when indicated, how it is done and main types

Doppler ultrasound, also called doppler ultrasound or color echo-doppler, is an important test to assess blood vessel circulation and blood flow in a particular organ or region of the body. Thus, it can be requested by the doctor in cases of suspected narrowing, dilation or occlusion of a blood vessel.

Some of the main indications of this exam are the evaluations of thrombosis, aneurysms or varicose veins, for example, and it is also widely used during pregnancy, to ascertain whether the blood flow from the mother to the fetus occurs properly, known as fetal doppler.

Like the common ultrasound exam, doppler ultrasound is performed using a device capable of emitting sound waves, which reach the tissue and return as an echo, which is converted into images. The doppler is the additional one capable of identifying and visualizing the blood flow at the site. Find out more about the main types of ultrasound and when they are indicated.

Doppler ultrasonography is performed by the doctor at imaging clinics or at the hospital, and is available free of charge by SUS or included in health plans. In particular, this exam can cost around 200 to 500 reais, however, the price is very variable according to the place where it is done, the area observed or if there are additional to the exam, such as 3D technology, for example.

What is it for

Some of the main situations in which it is indicated to do a color doppler ultrasound are:

• Study the functioning of blood flow in arteries and veins; Detect venous or arterial thrombosis; Diagnose and evaluate varicose veins; Measure blood flow from mother to fetus, through the placenta, during pregnancy; Identify aneurysms or dilations in blood vessels; Identify narrowing or occlusions in the veins and arteries.

The sound waves generated during the exam produce the image directly to the device's computer screen, so that the doctor can see if there are changes.

Care for the exam

The doppler ultrasound examination is simple and painless, requiring only lying on the stretcher while the doctor performs the examination. Fasting is not usually necessary, except for exams performed in the abdominal region, such as aortic doppler or renal arteries.

In these cases, a 10-hour fast and the use of medication for gases, such as dimethicone, may be indicated to reduce the formation of gases that may interfere with the examination.

Main types

Color doppler ultrasound can be requested to assess virtually all regions of the body. However, some of the doctor's main requests are for:

1. Doppler ultrasound of the legs

Called doppler of the lower limbs, it is usually requested to identify varicose veins, thrombosis, narrowing of blood vessels, to evaluate blood circulation before surgery in the region or even to assess the presence of symptoms of venous or arterial insufficiency, also called poor circulation.

Understand what can cause poor circulation and the main symptoms.

2. Doppler obstetric ultrasound

Also known as fetal Doppler, it is indicated by the obstetrician, and serves to assess blood vessels and the speed of blood flow from the umbilical cord and placenta, noting if there is any change in blood flow to the fetus, in order to plan better ways or the time for delivery.

This test is usually done in the third trimester of pregnancy, between 32 and 36 weeks, being especially necessary if the doctor suspects any alteration caused by situations such as under-growth, maternal diabetes, changes in the amount of amniotic fluid, gestation of twins or decreased movement of the fetus, for example.

3. Thyroid Doppler ultrasound

Thyroid doppler can be indicated by the endocrinologist to assess the characteristics of the thyroid blood vessels, in order to help program punctures. It is also useful to identify malignancy characteristics of a nodule, since the presence of excess blood vessels can be another indication of a suspicious nodule.

Learn more about when the thyroid nodule may be cancer.

4. Carotid Doppler Ultrasound

Carotids are arteries that carry blood from the heart to the brain, and when they suffer any changes, such as obstruction or narrowing, they can cause symptoms such as dizziness, fainting or even cause a stroke.

Therefore, carotid doppler is indicated by the doctor when these changes are suspected, to assess the risk of stroke and also in people who have suffered a stroke, to help identify the cause. Learn more at what the carotid ultrasound is for.

5. Doppler ultrasound of renal arteries

It is usually indicated by the nephrologist to study the flow of kidney arteries, seeking to identify narrowing and occlusions of these vessels, which are causes of hypertension that are difficult to control.

They may also be indicated to look for causes of kidney changes, such as decreased size, suspected aneurysms or deformities.

6. Doppler ultrasound of the aorta

It is indicated to assess the presence of dilations or an aneurysm in the aorta, which may be suspicious in people who have an abdominal murmur. It is also useful to investigate a dissection in this vessel, which is a serious complication caused by the detachment of its walls, or even to observe the presence of atherosclerosis plaques that can cause obstruction of the aorta.

This exam is also very important to schedule the correction surgery, if indicated by the doctor. Check out how to identify aortic aneurysm and how to treat it.