Ultrasound of the upper limb

Examination for thrombosis of the veins of the upper limb

Thrombosis most often affects the subclavian vein. Since the vein is located behind the clavicle, a sample with compression can not be performed. It is also difficult to squeeze the proximal and middle third of the axillary vein. Therefore, the main criterion for diagnosis of venous thrombosis of the upper limb is the detection of a lack of color blood flow. However, there may be color artifacts. When using compression and scanning the vessel in the longitudinal direction, it is possible to determine the true extent of thrombosis. Other veins of the neck, shoulder and distal section of the upper limb can be scanned and compressed, as indicated above. The examination can be supplemented with the use of samples with provocation, such as on the lower limb. Distal compression is performed in the same way as when examining the veins of the lower limb. The upper limb differs from the lower one in that a deep inspiration causes an acceleration of the venous blood flow due to a decrease in intrathoracic pressure.

Erroneous interpretation of ultrasound dopplerography data

Echogenic lumen (suspicion of thrombosis)

Intravascular echoes may be caused by excessive B-mode enhancement (too high gain) or unacceptable acoustic state

Free from echoes clearance (no signs of thrombosis)

Fresh thrombi can be transparent to ultrasound.

There is no signal from the blood flow in the lumen of the vessel (suspicion of thrombosis)

Very slow blood flow may lie outside the detection threshold, even with optimal sensor settings. Often the color signal can not be obtained immediately proximal or distal to thrombosis, as well as in the shin veins or in the standing position. Shadowing from calcified plaque can interfere with color examination

Detection of a color signal in the lumen of the vessel (no signs of thrombosis)

Incomplete or partially recanalized thrombosis can give a color signal, so before excluding thrombosis, make sure that the color completely fills the lumen. Sometimes this is difficult to achieve even in healthy individuals, and therefore distal compression is used. This technique can cause echoes of partial thrombosis.

Critical Assessment

Suspicion of deep vein thrombosis

Continuous-wave dopplerography is not used when two methods are possible: venography and ultrasound dopplerography. Ultrasound doppler ultrasound is more preferable because it is non-invasive and takes less time than venography. An experienced specialist can fully examine the entire lower limb within 5-10 minutes. The study may take longer in a diagnostic situation (about 5-10% of cases). The study conditions are excellent in the case when all the deep veins of the lower limb are seen in the B-mode. Deep vein thrombosis in these cases can also be excluded. However, in 10% of cases, the results of ultrasonic doppler ultrasound can be false-negative. Venography can be less informative than ultrasound shin dopplerography, due to the nature of the technique of administration, since the visualization of all three venous leg systems is incomplete. Visualization of muscle groups on the veins occurs randomly, so ultrasound is preferred in the detection of isolated thrombosis of the muscle veins.

In addition to the shin, another area that is difficult for ultrasound is the pelvis. Pelvic pelvic discharge in healthy individuals is the best method, although its interpretation may be difficult due to a "pseudotrombotic artifact" caused by unresolved blood from the deep femoral vein , large saphenous vein or internal iliac vein. In such cases, ultrasound dopplerography is a good addition to venography. In the presence of widespread thrombosis of the hip and shin, contrast enhancement at the level of the pelvis is usually not enough to confirm or exclude the defeat of the veins in this area. Again, an additional method of investigation is ultrasound dopplerography. With the same results, or if the surgeon wants to get a qualitative picture of the enhancement, the proximal location of thrombosis can be clarified with CT. It is extremely difficult to use ultrasound to assess the presence of recurrent thrombosis in postthrombotic syndrome. Venography is a standard technique for determining post-thrombotic changes in venous trunks, visualization of collaterals and differentiation of fresh and old changes.

Suspicion of vascular insufficiency

The extent of varicose veins in the large saphenous vein can be assessed using a small permanent-wave sensor. Unlike continuous wave Doppler ultrasound, Doppler ultrasound better determines the secondary or post-thrombotic insufficiency of the deep veins of the lower limb and perforating veins. However, in identifying the deficiency of the latter, the method of choice remains venography.

Suspicion of vein thrombosis of the upper limb

Ultrasonic dopplerography is the method of choice for revealing the causes of edema of the upper limb. Continuous-wave dopplerography is not used when ultrasound dopplerography or venography is possible. Venography better identifies collateral canals, but in patients with acute edema of the hand and venous signs of subclavian thrombosis, ultrasonic dopplerography can reveal clot laryngeal as a cause of acute edema. B-mode allows to identify or exclude thrombosis of the jugular vein.