Deep Vein Thrombosis (DVT) Point-of-Care Ultrasound (POCUS) 

Compression Ultrasonography (CUS)

The normal vein completely collapses with probe pressure.
A thrombosed vein does not compress.

Thus:

“Loss of compressibility = DVT until proven otherwise”

Types of DVT Exam

Sensitivity and Specificity Proximal DVT

Venous Anatomy Relevant to DVT POCUS

Lower Extremity Deep Venous System

Proximal veins

1. Common femoral vein (CFV)
2. Femoral vein (formerly superficial femoral vein)
3. Deep femoral vein
4. Popliteal vein

Distal calf veins

1. Posterior tibial veins
2. Peroneal veins
3. Anterior tibial veins
4. Muscular calf veins
• Soleal
• Gastrocnemius

Clinically  Classification

Ultrasound  Probe Selection

Patient Positioning

Reverse Trendelenburg

OR

Supine with knee slightly flexed and externally rotated

This:

• Distends veins
• Improves visualization

For popliteal vein:

• Knee flexed
• Lateral decubitus/prone

Ultrasound Modes Used

Compression Ultrasound Technique

Apply probe pressure every:

• 1–2 cm above and below Points depending on 2 point or 3 point scan  along vein course

2-Point Lower Extremity DVT Ultrasound: compression ultrasound including the femoral vein 1 to 2 cm above and below the saphenofemoral junction and the popliteal vein up to the calf veins confluence.

3-Point Lower Extremity DVT Ultrasound: compression ultrasound including the femoral vein 1 to 2 cm above and below the saphenofemoral junction, 1 to 2 cm above and below the bifurcation of the common femoral vein into the deep femoral vein and the (superficial) femoral vein, and lastly the popliteal vein up to the trifurcation into the anterior tibial vein, the posterior tibial vein, and the peroneal vein (Garcia 2018).

A normal vein:

• Completely disappears

A thrombosed vein:

• Partially compresses or not at all

How much pressure to apply-You should apply pressure until the pulsatile artery compresses slightly. If the adjacent vein compresses completely, there is no DVT

Acute vs Chronic DVT

Iliac Vein DVT

Difficult to visualize directly

Indirect signs:

• Loss of respiratory variation
• Continuous femoral waveform
• Extensive unilateral edema

Can use:

• Curvilinear probe
• Abdominal approach

Upper Extremity DVT POCUS

Common in:

• Central venous catheters
• PICC lines
• Malignancy

Evaluate:

1. Internal jugular vein
2. Subclavian vein
3. Axillary vein
4. Brachial veins

Challenge: Subclavian Vein

Cannot compress due to clavicle.

Diagnosis relies on:

• Doppler
• Color flow
• Loss of respiratory variation

Limitations of POCUS

False Negatives

Occur with:

• Calf DVT
• Nonocclusive clot
• Iliac thrombosis
• Obesity
• Severe edema
• Inexperienced operator

False Positives

• Chronic post-thrombotic changes
• Lymph nodes(disappear quickly if you attempt to trace it up and down)
• Baker cyst
• Hematoma

Mimics of DVT

Solution-identify that the vein is next to an artery. compare the vein in Short Axis(Circular ) and Long Axis views(Cylindrical)

Pregnancy and DVT Ultrasound

Pregnancy predisposes to:

• Left-sided DVT
• Iliac vein thrombosis

Challenges:

• Iliac compression by uterus

Indirect findings important.

Reporting DVT POCUS

Example:

“Noncompressible right popliteal vein with intraluminal echogenic thrombus consistent with acute proximal DVT.”

Special Situations

Phlegmasia Cerulea Dolens

Massive iliofemoral thrombosis causing:

• Severe edema
• Cyanosis
• Ischemia

POCUS:

• Extensive noncompressible proximal veins

Medical emergency.

May-Thurner Syndrome

Compression of:

• Left common iliac vein by right iliac artery

Suggest when:

• Recurrent left DVT
• Young female
• Iliac obstruction signs

REFERENCES

1. https://www.pocus101.com/dvt-ultrasound-made-easy-step-by-step-guide/
2. Varrias D, Palaiodimos L, Balasubramanian P, Barrera CA, Nauka P, Melainis AA, Zamora C, Zavras P, Napolitano M, Gulani P, Ntaios G, Faillace RT, Galen B. The Use of Point-of-Care Ultrasound (POCUS) in the Diagnosis of Deep Vein Thrombosis. J Clin Med. 2021 Aug 30;10(17):3903. doi: 10.3390/jcm10173903. PMID: 34501350; PMCID: PMC8432124.