Upper Extremity Venous Thrombosis: Segmental Ultrasound Protocol
Study Objective
Ultrasound for suspected upper extremity venous thrombosis addresses practical questions: is there a thrombus, in which venous system is it located, is it occlusive or non-occlusive, acute or chronic based on sonographic appearance, and is it associated with a catheter or other intravascular device. The AIUM Practice Parameter for Peripheral Venous Ultrasound, 2024 considers peripheral venous ultrasound as a study combining grayscale imaging, compression, color, and spectral Doppler.
For the upper extremity, it is crucial not to mechanically transfer the leg protocol: part of the central veins of the arm is covered by the clavicle and the first rib, so direct compression criteria are limited there. The protocol should be segmental: each accessible section is checked by compression, and the inaccessible ones by Doppler signs of patency and indirect signs of central obstruction.
Minimum Set of Modes
- B-mode: assessment of lumen, walls, intravascular material, catheter, perivenous changes.
- Compression with the probe: the main technique in accessible veins. A normal vein completely collapses under adequate probe pressure.
- Color Doppler: confirms lumen filling with blood flow, identifies filling defects, and helps in segments where compression is impossible or incomplete.
- Spectral Doppler: assesses spontaneity, phasicity, variability of blood flow, response to respiration, and distal augmentation when technically applicable.
Compression should not be replaced by color Doppler in segments where it is feasible. Color and spectral Doppler enhance evidence, but vein incompressibility remains the central sign of thrombosis in accessible areas.
Segmental Protocol for the Upper Extremity
| Segment | What to Include in the Protocol | Key Limitations and Signs |
|---|---|---|
| Internal Jugular Vein | B-mode, transverse compression, color and spectral Doppler | Assess patency, collapsibility, filling defect; asymmetry of the spectrum may indicate central obstruction |
| Subclavian Vein | B-mode through available windows, color Doppler, spectral curve | Full compression often impossible due to bony structures; color filling, phasicity, and side comparison are important |
| Axillary Vein | Compression, B-mode, color and spectral Doppler | One of the key accessible deep segments; document thrombus occlusiveness |
| Brachial Veins | Serial compression along the veins, color Doppler if in doubt | Veins are paired; important not to limit to one vein next to the artery |
| Basilic and Cephalic Veins | Examine if symptoms, catheter, local pain, or swelling are present | Describe superficial thrombosis separately from deep; indicate spread to deep veins |
| Forearm Veins | Evaluate if distal symptoms, catheter, local thrombophlebitis are present | Technical accessibility depends on swelling, depth, and caliber of veins |
| Brachiocephalic Veins and Superior Vena Cava | Direct visualization if possible, more often indirect spectrum assessment | Lack of normal phasicity or pronounced flow asymmetry supports suspicion of central obstruction but requires clinical correlation |
Sonographic Signs of Thrombosis
The main direct sign in an accessible segment is the inability to fully collapse the vein upon compression. Additional signs: echogenic or hypoechoic material in the lumen, vein enlargement in acute processes, absence or incomplete color filling, absence of normal spontaneous blood flow in the occluded segment.
A non-occlusive thrombus may retain part of the color flow peripherally or through a residual lumen. Therefore, the protocol should describe not only the presence of a thrombus but also the degree of lumen impairment qualitatively: occlusive or non-occlusive. In case of doubt, multiple scanning planes, changing the insonation angle, and correlating B-mode with color Doppler are useful.
Acute, Chronic, and Post-Thrombotic Process
| Conclusion | Typical Ultrasound Signs | How to Formulate |
|---|---|---|
| Acute Thrombosis | Non-compressible segment, intraluminal material, flow defect; vein may appear enlarged | Specify the vein, extent by segments, occlusiveness |
| Non-Occlusive Thrombosis | Vein does not fully collapse, but part of the color flow is preserved | Specify residual lumen and direction of spread |
| Chronic or Post-Thrombotic Changes | Wall thickening, intravascular strands, incomplete compression, collaterals, recanalization | Do not label as acute thrombosis without corresponding signs and clinical context |
| Superficial Venous Thrombosis | Non-compressible superficial vein with thrombotic content | Indicate separately the connection to the deep system |
| Limited Study | Segment not visualized or cannot be reliably compressed | Name the reason for limitation and which indirect signs were assessed |
Doppler in Central Segments
Subclavian, brachiocephalic veins, and the superior vena cava area are typical protocol challenges. If compression is impossible, one cannot write "thrombosis excluded" based solely on incomplete B-mode. It is necessary to document color filling, spectral curve, symmetry with the opposite side, and presence of collaterals.
Normal venous spectrum in central veins of the upper extremity is usually spontaneous and phasic, influenced by respiration and cardiac activity. Loss of expected variability, monophasic nature, pronounced asymmetry, or absence of flow combined with clinical context increases the likelihood of proximal or central obstruction. These signs do not replace direct thrombus visualization but should be reflected in the conclusion as a basis for further imaging if the clinical question remains unresolved.
Catheter-Associated Thrombosis
In the presence of a central venous catheter, PICC, port system, or electrodes, the protocol should explicitly indicate the device and the vein it traverses. A thrombus may adhere to the catheter, partially surround it, or cause vessel occlusion. In B-mode, it is important to distinguish the vein wall, catheter, and intravascular material; color Doppler helps assess residual blood flow around the device.
The conclusion should be anatomical: for example, thrombosis of the axillary and subclavian veins on the catheter side, non-occlusive thrombus around the catheter in the brachial vein, superficial thrombosis of the basilic vein without transition to the deep system. Such formulation is more useful than the general term "arm thrombophlebitis."
Image Documentation
AIUM 2024 emphasizes the need to document the performed elements of the study. For a practical protocol, this means saving images of compression before and after probe pressure in accessible veins, color maps in suspicious areas, and spectral curves in central or proximal segments. If a segment is not examined due to a bandage, wound, severe pain, immobilization, swelling, or technical window, this should be stated in the protocol.
For a positive study, it is desirable to save transverse and longitudinal visualization of the thrombus, color defect, spectrum before or after the affected area, and an image of the anatomical landmark. For a negative study, show compression of key accessible segments and Doppler patency of the subclavian area.
Conclusion Template
Normal: The deep veins of the examined upper extremity are patent; accessible segments fully compress; color blood flow is preserved; spectral blood flow in proximal veins is phasic; no signs of thrombosis detected. Indicate if superficial veins were assessed and are patent.
Acute Thrombosis: Ultrasound signs of thrombosis in such vein(s), with spread from segment to segment; thrombus is occlusive or non-occlusive; if a catheter is present, its association; superficial system involved or not involved.
Limited Study: Indicate which segments were reliably assessed, which were not, and why; describe Doppler data supporting or not supporting central obstruction. Such formulation reduces the risk of falsely excluding thrombosis in the inaccessible subclavian-brachiocephalic area.
Typical Errors
- Limiting only to the site of pain without assessing proximal veins.
- Recording "subclavian vein compresses" without the real possibility of full compression under the clavicle.
- Lack of description of superficial veins in the presence of a catheter or local thrombophlebitis.
- Mixing superficial and deep thrombosis in one vague conclusion.
- Excluding central obstruction without spectral Doppler and side comparison when visualization is poor.
Frequently asked questions
Can upper extremity thrombosis be excluded by compression alone?
No. Compression is the main criterion in accessible veins, but subclavian and central veins often do not compress due to anatomy. Therefore, according to AIUM 2024, the protocol should be supplemented with color and spectral Doppler.
Should the cephalic and basilic veins be examined?
Yes, if there are local symptoms, a catheter, infusion history, or suspicion of superficial thrombosis. In the conclusion, superficial thrombosis is described separately, and it is indicated whether there is a transition to the deep system.
How to write a conclusion with poor visualization of the subclavian vein?
It is necessary to indicate the limitation, describe the available B-mode, color and spectral Doppler, comparison with the other side, and presence of indirect signs of central obstruction. The formulation "thrombosis excluded" is permissible only for reliably assessed segments.