Doppler scanning (duplex scanning) is a method of diagnosing vascular pathology using ultrasound, which has no age restrictions, is painless, harmless to health, has no contraindications during pregnancy, does not require special training of the patient.
"Doppler effect" - based on the shift of the frequency of ultrasound when it is reflected from moving blood particles. The image in the ultrasound examination of blood vessels is due to the fact that ultrasonic waves emitted by special ultrasonic sensors passing through a blood vessel are differently reflected from blood cells (erythrocytes), depending on how they move inside the vessel blood flow velocity). The reflected waves are captured by the ultrasound sensor and after conversion to electrical pulses are displayed on the monitor in real time in the form of graphs and color photographs (the use of color helps to conduct a more thorough examination. In this case Dark shades of these colors correspond to low speeds, light - high), which represent the flow of blood through blood vessels.
Vascular ultrasound allows you to see in real time the vessels "from the inside", thus making it possible to determine changes in blood flow in the vessels associated with spasm, narrowing or thrombosis.
Doppler imaging examines not only the main vessels (arteries and veins), but also the vessels of internal organs, which change their characteristics in the event of a disease.
At the present stage, the vessels of the brain, neck, upper and lower extremities, the aorta and its branches are examined by Doppler. At present, cardiac ultrasound cannot be considered complete if only the M-method and a two-dimensional echocardiogram are used. Doppler method has become mandatory, which allows the use of ultrasound to determine the direction and speed of blood flow in different parts of the cardiovascular system.
Doppler is also used to determine blood flow to the fetus during pregnancy.
The survey has no age restrictions or contraindications.
The examination does not require special training, except to eliminate factors that can affect the tone of the arteries. It is recommended to stop taking medications that may affect vascular tone a few days before the scan and to warn your doctor about other medications you are taking. It is also recommended to limit yourself in the consumption of energy drinks, tea and coffee. This also applies to heavy physical activity, smoking, visiting the sauna or bath.
Stages of implementation
Vascular ultrasound (Doppler) is a completely painless and safe procedure that lasts from 30 to 60 minutes (depending on the required volume of examination).
A special gel is applied to the study area, which improves the transmission of ultrasound signal. The doctor in real time displays the image on the ultrasound screen and makes the necessary measurements (studies the condition of blood vessels: their patency, assesses blood flow, diameter of the lumen of the vessel, the presence of intravascular formations).
After that, the specialist makes a conclusion based on the results of ultrasound.
What the survey shows
Doppler examination of arteries allows to assess the structure of the wall, the presence and nature of atherosclerotic plaques, to measure the speed and direction of blood flow, to assess the degree of narrowing, to identify developmental abnormalities.
Doppler ultrasound of the heart allows you to assess the speed and direction of blood flow in different chambers of the heart. The appearance, for example, of blood flow from the left ventricle to the left atrium is evidence of mitral valve insufficiency, and the throwing of blood flow from the aorta to the left ventricle is a reliable diagnostic sign of aortic valve insufficiency. If, in addition, on the basis of a two-dimensional echocardiogram to calculate the area of the hole through which blood flows, then, knowing the time for which the ejection of blood, you can calculate its amount passing through this area of the cardiovascular system. The errors of the method are mainly due to the difficulties associated with accurate measurement of the area of the hole through which the blood flow. Similarly, the amount of blood flowing per unit time through any heart valve or intracardiac shunt can be calculated. This allows you to not only register the presence of a heart valve failure, but also to measure the amount of regurgitation. Doppler echocardiography can also be used to quantify the degree of valve stenosis.
Examination of the veins additionally evaluates their patency, the condition of the valves, the diameter of the lumen, the presence or absence of blood clots, which significantly increases the accuracy in the subsequent diagnosis.
Color duplex scanning allows not only to see the vessel, its walls, surrounding tissues, but also the movement of blood through the vessel, its direction, speed, obstacles that disrupt normal blood flow (plaques, blood clots, etc.). Duplex scanning provides reliable information about the condition of blood vessels, allows you to establish or confirm the diagnosis and, most importantly, help to properly and adequately plan further treatment.
Any test results should be evaluated not only by a functional diagnostician, but also by another specialist (cardiologist, phlebologist, neurologist, surgeon, etc.) for further tests.