Doppler ultrasound or simply eco Doppler is a very useful test to get detailed information on the morphology and functionality of the blood vessels. In a nutshell, this type of test allows you to study venous and arterial circulation through a simple ultrasound to evaluate the state of the blood vessels and the flow of blood inside them.
The doppler is a quick (about 15-30 minutes) and non-invasive test that assesses the speed and direction of blood flow. In addition, it allows highlighting numerous heart and vascular diseases, both in adults and in children. Performing the doppler does not involve any pain or discomfort. Let's see in detail how it works, what it is used for, and when it is recommended to perform it.
The correct and complete name of this test is Eco-Color-Doppler, a name that derives in part from the work of Johann Christian Doppler. He was a mathematics professor at the secondary school in Prague, who published his work “On the colored light of double stars and certain other celestial stars.” In this study, Professor Doppler describes what will later be known as the “Doppler effect.”
The machine to perform the doppler is an ultrasound machine, that is, an instrument capable of obtaining an image using and analyzing ultrasound, that is, mechanical waves with a frequency greater than 20KHz.
The image is generated by the ultrasound using the physical properties and biological interaction of ultrasound. In the ultrasound probe, there are crystals that, when crossed by electric current, generate ultrasound waves that pass through the various anatomical structures. The eco-reflex signal forms the images from the anatomical structures. The ultrasounds emitted by the probe are reflected by the circulating blood, with a frequency different from that of emission and proportional to the scrolling speed.
That's why the doppler provides valuable information on the speed of blood flow and its direction.
There are two types of Doppler:
1. Continuous-wave, in which the reception and emission of ultrasound are continuous and allows to measure accurately even high-speed flows.
2. Pulsed, in which the ultrasound beams are emitted and received at alternate times. The advantage of this technique is that it allows you to measure the speed of flows at a set depth and also to locate the anatomical structure that generates them.
The pulsed methodology has taken a step forward with the advent of the eco -color Doppler, which allows obtaining even more precise information on the blood flow, due to the production of color images, with a chromatic spectrum ranging from red to blue.
The Doppler is a first-level diagnostic test, reproducible, and at a low cost. In addition, it can be repeated frequently without contraindications.
The Doppler is used to study the entire circulatory system. It provides black and white or color (red and blue) images of venous and arterial flows. Furthermore, it also highlights the smallest lesions of the vessels and thus allows a precise assessment of the extent of the damage. It can be very useful for evaluating the main vascular diseases:
- venous insufficiencies
- Identify atherosclerotic lesions, i.e., those plaques that obstruct blood flow and can cause venous thrombosis.
Therefore, this test is indicated in the case of suspect diseases for checking the health of veins and arteries. It is recommended, in particular for people at risk of:
- cardiovascular diseases
- People with high familiarity with arterial and venous pathologies.
The Doppler is normally performed in the clinic, in some cases, in a relaxed position, and in others with the patient standing. The part of the body to be examined is sprinkled with a specific gel, which serves to interpose an eco-transmitting substance between the skin and the probe, because the air does not allow the passage of ultrasound. The probe is placed on the part to be examined to obtain images on a connected screen.
It is a very safe test that uses ultrasound and not radiation, so it does not cause any side effects.
In this case, we study the main vessels that bring blood to the brain:
- Carotid and vertebral arteries.
This test is used to check whether or not there are plaques at the level of the carotid bifurcation and at the level of the internal carotid artery. These types of plaques are one of the causes of ischemic stroke.
It is recommended for those who are familiar with or risk factors, which predispose to the appearance of cardiovascular diseases (smoking, diabetes, hypercholesterolemia, and hypertension), especially from 50 years onwards. The test lasts about 20 minutes and does not require any preparation.
The aorta is the largest and most important artery in the body, starts from the left ventricle of the heart, crosses the thorax, and carries oxygenated blood into the abdomen and all organs. The abdominal aorta echo color Doppler allows you to check for plaques at the level of the aorta or iliac arteries. Furthermore, it allows investigating the possible presence of stenosis of the renal arteries. Stenoses are responsible for forms of arterial hypertension resistant to drug therapy and, in the long term, also for renal failure.
Finally, this test is useful to evaluate the presence of possible aneurysms of the abdominal aorta, that is, of the dilations of the vessel that can cause breakage and subsequent abdominal bleeding.
This test is specifically suggested for people who have overweight subjects, smokers, people with hypertension, heart disease, hypercholesterolemia, and atherosclerotic. It is recommended for such as adult males over sixty and for those who are familiar or first-degree family members affected by these diseases.
It lasts less than 30 minutes to carry out the test; it is necessary to be fasting in the previous 6 hours and to carry out a low-slag diet in the three days preceding the test.