Method of examination of veins of lower extremities

A system of deep and superficial veins of both lower extremities is mandatory for ultrasound examination. In the deep vein system it is a common and deep femoral vein, superficial femoral vein, popliteal vein, all groups of trunk veins of the shins and veins of the foot. Now, with sensors operating in the range of 5-13 MHz, we can easily examine all the deep veins of the lower extremities from the inguinal ligament to the veins of the dorsum and plantar surface of the foot.

To study the veins of the thigh, popliteal vein, vein of the tibia, as well as large and small subcutaneous veins, use a linear sensor with a frequency of 5-15 MHz. For visualization of the iliac veins and inferior vena cava, a 3.5-MHz convection sensor is used. When scanning the inferior vena cava, iliac, large saphenous vein, femoral veins and veins of the lower leg, the patient is in the supine position on the back. The study of popliteal veins, veins of the upper third of the shin and a small saphenous vein is carried out in the supine position. In the latter case, the patient is asked to put his feet on the toe, providing relaxation to the back group of the leg and thigh muscles. With severe pain syndrome or the inability of patients to take the necessary position, a popliteal vein study is performed with the help of a nurse (doctor), who raises the patient's leg. Gypsum dressings are cut before the test.

The depth of scanning, amplification of echoes and other parameters of the study are selected individually for each patient and remain unchanged throughout the survey, including observations in dynamics.

Acoustic gel is applied to the skin above the examined vein. The veins of the deep venous system correspond anatomically to the arteries of the lower extremities. Surface veins (large and small subcutaneous veins) do not correspond to the arteries and lie in the fascia dividing the surface and deep tissues.

Scanning is started in the cross section, to exclude the presence of the floating top of the thrombus, as evidenced by the full contact of the venous walls during light compression by the sensor. After making sure that there is no freely floating top of the thrombus, the compression probe is passed from the segment to the segment, from the proximal to the distal segments. The proposed method is most accurate not only for detecting, but also determining the extent of thrombosis (excluding the iliac veins and the inferior vena cava, where DCC is used for the permeability of veins). Longitudinal scanning of the veins confirms the presence and characteristics of venous thrombosis. In addition, the longitudinal section is used to locate the anatomical fusion of veins.

As a rule, three regimens are used to study the veins of the lower limbs. In the B-mode, the diameter of the vein, the collapsing of the walls, the lumen, the presence of valves are estimated. In the color (or energy) mode, the full staining of the vein lumen, the presence of turbulent flows are revealed. In the spectral Doppler ultrasound mode, the phase of the blood flow is determined.

In the patient's position, lying on the back in the inguinal ligament region, a common femoral vein is lobed, and the sapheno-femoral joint of the common femoral and large saphenous veins is visualized below the inguinal ligament. When moving the sensor down, a fusion of the deep femoral vein and femoral vein into the common femoral vein is fused. At this position of the sensor, the deep femoral vein is usually visible only in the proximal part. The femoral vein is defined all over the anterior medial surface of the thigh. The popliteal vein is examined from the popliteal fossa region. Moving the sensor distally, the proximal parts of the crural veins are scanned. Anterior tibial veins locate on the anterolateral surface of the tibia, between the tibial and fibular bones. The posterior tibial veins are visualized from anterior medial access along the edge of the tibia. Tubular veins locate from the same access as the posterior tibial veins, when the sensor is moved closer to the gastrocnemius.

The study of a large saphenous vein is carried out from the sapheno-femoral anastomia to the level of the medial malleolus along the anterior medial surface of the thigh and lower leg. Starting from the level of the Achilles tendon, a small subcutaneous vein is scanned along the middle line of the tibia up to the popliteal vein.

Examination of the inferior vena cava begins from its proximal part, from the right atrium, displacing the sensor distally along the vein, tracing it all the way. To visualize the iliac veins, the sensor is placed in series over the projection of the right and left vessels. For a more detailed evaluation of the inferior vena cava and left iliac veins, the study is supplemented (if possible) by turning the patient to the left side.

Normally, the lumen of the vein is anechoic, the walls of the vein are elastic, thin, they fall off when performing compression tests. Venous valves in the lumen, the "spontaneous echo-contrasting effect" can be determined. In the mode of color and energy coding, the vein lumen is completely stained. With spectral Doppler, a phase synchronized with the respiration blood flow is recorded.

After exclusion of violation of the permeability of veins in the system of the inferior vena cava, an analysis of the functioning of the valvular apparatus and the detection of all veno-venous refluxes are performed. Examination is performed in the horizontal and vertical positions of the patient. A Valsalva sample with standard expiratory pressure values and a proximal compression test were used. The survey is performed by a linear sensor with a frequency of 7.5-10 MHz. When determining the function of the valve apparatus, a Valsalva test is performed. The patient is asked to perform a maximum inspiration with simultaneous straining for 0.5-1.0 s and holding the intra-abdominal pressure for 10 seconds. In healthy people, there is a weakening of the venous blood flow with inspiration, a complete disappearance of it during straining and an increase in blood flow with a subsequent exhalation. The insufficiency of the valves of the vein being examined is indicated by the appearance of retrograde blood flow during straining.

The proximal compression gives information similar to the Valsalva test, in cases of difficult Valsalva test or in the study of the popliteal veins, the vein is squeezed proximally to the valve for 5-6 seconds. If the valves fail, retrograde blood flow occurs.

To detect signs of valvular insufficiency, you can use respiratory and cough tests. With the respiratory sample, the patient takes the deepest breath, with a cough test - a series of coughing movements, which leads to the appearance of retrograde blood flow in the presence of the pathology of the valve apparatus.

In the superficial veins, the condition of the ostial valve of the large saphenous vein and then of all the other valves in this vein over its entire length is evaluated first. In the small saphenous vein - the state of the valves in its mouth and throughout the vessel.

In a deep venous system, a valve apparatus is examined in the superficial femoral vein, popliteal vein, the veins, deep veins of the shin. That is, it is expedient to examine those valve structures of the veins of the lower extremities that are subject to surgical correction. Naturally, all the perforator veins revealed during the examination are also studied for their valvular insufficiency.

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