Duplex scanning is a combination of traditional ultrasound examination (in B-mode) with Doppler techniques for determining blood supply and blood flow. This combination is a very effective diagnostic method in modern angiology.
Duplex scanning in phlebology is considered the “gold standard”. Modern phlebology in almost all cases uses this technique for diagnosis. Duplex scanning of veins helps to visualize the vasculature, considerable in length, by registering the movement of blood in it. The use of this method is necessary not only for the diagnosis, but also for the treatment and prognosis of venous pathology.
There are various approaches to performing this procedure. The screening approach allows only basic questions to be determined, a small number of ultrasound diagnostics doctors without first consulting this patient with a phlebologist can give a detailed description of the state of the veins. A small amount of time is allocated for examination, approximately 10 minutes. For example, a duplex scan of the veins of the lower extremities (full!) Should take 40-50 minutes. Ultrasound can be used to screen for venous pathology : it allows you to identify bottlenecks that can then be examined in more detail with duplex scanning.
A more detailed and informative study will be a duplex scan secondary, after a visit to a phlebologist, who will outline the necessary questions for solution and clarification. If this procedure is carried out before his visit, then often there is a need to repeat it, as unresolved questions arise at the phlebologist’s appointment.
At the reception, a foot examination is first carried out to identify places that need special attention. Inspection must be carried out both in the prone position (deep veins are better visible) and in the standing position (in this case, superficial). With the help of a sensor, every centimeter of the leg is examined. There are preclinical stages of diseases that can only be determined using ultrasound.
The venous pool of the lower extremities includes 26 veins on each side. Often found to be with diseases of the vein of the foot.
As already mentioned, duplex scanning consists of a combination of ultrasonic B-mode and Doppler. In B-mode, the device emits ultrasound of a certain frequency, penetrating through the tissue. The border of tissues of different densities causes ultrasound reflection and its return back to the sensor. This sensor is pulsed. The greater the distance between the sensor and the boundary, the more time will pass from the radiation of ultrasound to its capture. Thus, there is a scanning and two-dimensional reconstruction of the investigated vessels. The Doppler mode is based on the effect of the same name: ultrasound in a collision with moving particles not only reflects, but also changes the frequency, and the change in this parameter is proportional to the speed of the moving object. In the study of the vasculature, the moving objects are red blood cells. At the present stage, it is possible to build a color cartogram of the flow in the vessel, in which the intensity and direction of blood flow are encoded using color. This method is color Doppler mapping.
Using these two modes, you can get information about the anatomy of the vessels, the state of their walls and lumens, evaluate the changes in them themselves, and track the changes in hemodynamics. In addition, this method is non-invasive, and also allows you to diagnose a significant amount of vascular pathology.