Upper extremity vein ultrasound

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 compression test cannot be performed. It is also difficult to compress the proximal and middle thirds of the axillary vein. Therefore, the main criterion for diagnosing thrombosis of the veins of the upper limb is to detect the absence of color blood flow. However, color artifacts may occur. By using compression and scanning the vessel in the longitudinal direction, the true extent of the thrombosis can be determined. Other veins of the neck, shoulder, and distal upper limb can be scanned and compressed as described above. The examination can be supplemented by provocation tests, 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 in that a deep breath causes an acceleration of venous blood flow due to a decrease in intrathoracic pressure.

Misinterpretation of Doppler ultrasound data

Echogenic lumen (suspected thrombosis)

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

Echo-free lumen (no signs of thrombosis)

Fresh thrombi may be transparent to ultrasound.

No signal from blood flow in the lumen of the vessel is detected (suspected thrombosis)

Very slow blood flow may lie below the detection threshold even with optimal transducer settings. Often, color signal cannot be obtained immediately proximal or distal to the thrombosis, nor in the leg veins or in the standing position. Shadowing from calcified plaque may interfere with color examination.

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

Incomplete or partially recanalized thrombosis may produce 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, which is why distal compression is used. This technique may cause echo filling of partial thrombosis.

Critical assessment

Suspected deep vein thrombosis

Continuous wave Dopplerography is not used when two methods are available: venography and ultrasound Dopplerography. Ultrasound Dopplerography is preferable because it is noninvasive and takes less time than venography. An experienced specialist can completely examine the entire lower limb within 5-10 minutes. The examination may take longer in diagnostically difficult situations (about 5-10% of cases). The examination conditions are excellent when all deep veins of the lower limb are visible in B-mode. Deep vein thrombosis of the leg can also be excluded in these cases. However, in 10% of cases, the results of ultrasound Dopplerography of the leg may be false negative. Venography may be less informative than ultrasound Dopplerography of the leg due to the peculiarities of the injection technique, since visualization of all three venous systems of the leg is incomplete. Visualization of muscle groups on venograms occurs accidentally, therefore ultrasound is preferable in detecting isolated thrombosis of muscle veins.

In addition to the leg, another difficult area for ultrasound is the pelvis. Pelvic venography in healthy individuals is the best method, although its interpretation may be complicated by the “pseudothrombotic artifact” caused by non-enhanced blood from the deep femoral vein , great saphenous vein, or internal iliac vein. In such cases, Doppler ultrasound is a good adjunct to venography. In the presence of widespread thrombosis of the thigh and leg, contrast enhancement at the pelvic level is usually insufficient to confirm or exclude venous involvement in this region. Again, Doppler ultrasound is an adjunct. If the results are identical, or if the surgeon wants to obtain a high-quality enhancement pattern, the proximal location of the thrombosis can be clarified by CT. It is extremely difficult to assess the presence of recurrent thrombosis in postthrombotic syndrome by ultrasound. Venography is a standard technique for determining post-thrombotic changes in venous trunks, visualizing collaterals and differentiating between fresh and old changes.

Suspected vascular insufficiency

The extent of varicose veins of the great saphenous vein can be assessed using a small continuous wave sensor. Unlike continuous wave Dopplerography, ultrasound Dopplerography better identifies secondary or post-thrombotic insufficiency of the deep veins of the lower limb and perforating veins. However, venography remains the method of choice for detecting insufficiency of the latter.

Suspected thrombosis of the veins of the upper limb

Ultrasound Doppler is the method of choice for identifying the causes of upper extremity edema. Continuous-wave Doppler is not used when ultrasound Doppler or venography is available. Venography better identifies collateral channels, but in patients with acute arm edema and venographic evidence of subclavian thrombosis, ultrasound Doppler may identify collateral thrombosis as the cause of acute edema. B-mode can identify or exclude jugular vein thrombosis.