DVT ultrasound

Background

DVT of the common femoral vein.

DVT in the (superficial) femoral vein. There is absence of blood flow as well as hyperechogenicity in the thrombosed vessel, as compared to the deep femoral vein (bottom) and the femoral artery (top).

• Bedside ultrasound can be used to conduct compression testing on lower extremity vasculature to assess for DVT
• Intended to be rapid, limited, but revealing most clinically significant DVTs
• Amongst ED providers, there is a sensitivity of 95% and specificity of 96%

Indications

• Clinical suspicion of DVT: edema, tenderness over the calf, Homan's sign
• Clinical suspicion of PE: chest pain, shortness of breath, tachycardia, tachypnea

Technique

Sites of Compression for 3-Point Evaluation

1. Common Femoral Vein
2. Saphenofemoral Junction
3. Popliteal Vein

Steps

1. Select transducer
   • Linear array vascular probe 6–10 MHz
   • For morbidly obese patients, consider abdominal probe
2. Common Femoral Vein and Saphenofemoral Junction
   • Patient positioning
     • Reverse Trendelenburg or semi-sitting with 30 degrees of hip flexion
     • Mild external rotation (30 degrees) hip
   • Probe at medial inguinal crease
   • Apply generous compression every centimeter
   • Continue distal to 1-2cm beyond bifurcation of the common femoral vein
3. Popliteal vein
   • Patient positioning
     • Prone, decubitus position, or seated on edge of gurney
     • Knee flexed 10–30 degree
     • Reverse Trendelenburg
   • Start with light pressure to better visualize vessels
   • Apply generous compression over the popliteal vessels to test compressibility
   • Vein usually superficial to the artery (artery is anterior)

Findings

• Each segment of vein identified must be assess as compressible and noncompressible
  • Touching of the anterior and posterior walls indicates a normal exam
  • No touching with pressures sufficient to deform the artery indicates DVT

Images

Normal

Abnormal

File:DVT Bowra

Incompressible left Common Femoral Vein

Pearls and Pitfalls

• Arteries are the thick walled and more circular vessels identified
• Doppler flow can be used to identify different directions of flow in vessels and to identify no vascular structures
• Noncompressible vein may be mistaken for an artery, leading to a false negative result
• An artery may be mistaken for a non-compressible vein, leading to a false positive result
• Lymph nodes may be confused with noncompressible vein and if found, can be identified by moving up or down 1 cm
• Does not rule out calf DVTs
• For a more thorough exam, scan from the saphenofemoral junction down through the adductor canal in addition to the areas described above
• Use a curvilinear probe for obese or edematous patients
• An appropriate amount of pressure gives complete collapse of the vein as well as some (but not full) compression of the adjacent artery.

Documentation

Normal Exam

A bedside ultrasound was conducted to assess for DVT with clinical indications of edema and pain. The extremity was assessed at 3 locations – common femoral vein, saphenofemoral junction, and the popliteal vein. Sequential compressions at these sites showed fully compressible veins. No sonographic evidence of DVT at these sites.

Abnormal Exam

A bedside ultrasound was conducted to assess for DVT with clinical indications of edema and pain. The extremity was assessed at 3 locations – common femoral vein, saphenofemoral junction, and the popliteal vein. Sequential compressions at these sites showed a noncompressible popliteal vein. DVT is present at the level of the popliteal vein.

Clips

Normal Study - No DVT

Abnormal Study - Incompressible left Common Femoral Vein

External Links

• ACEP – Focus On Emergency Ultrasound for DVT
• Focused Lower Extremity Venous Ultrasound

See Also

• Ultrasound (Main)
• Deep venous thrombosis
• Pulmonary embolism
• Paget-Schroetter syndrome