What type of ultrasound, arterial or venous, is used for diagnosing Deep Vein Thrombosis (DVT)?

DVT Diagnosis Uses Venous Ultrasound

For diagnosing deep vein thrombosis (DVT), you perform ultrasound of the VEINS, not arteries—specifically duplex venous ultrasonography examining the deep venous system. 1

Why Venous Ultrasound is the Standard

Duplex venous ultrasonography is the preferred imaging method for initial DVT diagnosis because it evaluates venous compressibility and Doppler flow patterns in the deep veins where thrombi form. 1

The technique specifically targets:

• Deep veins (femoral, popliteal, posterior tibial, peroneal) where DVT occurs 1
• Venous compressibility as the most definitive diagnostic criterion—thrombosed veins don't compress 1
• Venous flow patterns using Doppler to assess for obstruction 1

Complete Duplex Ultrasound Protocol

The recommended protocol is comprehensive duplex ultrasound (CDUS) from inguinal ligament to ankle, not limited proximal-only studies. 1, 2

Key components include:

• Compression at 2-cm intervals from common femoral vein through ankle, including calf veins (posterior tibial and peroneal) 1, 3
• Spectral Doppler of bilateral common femoral veins to assess symmetry 1, 3
• Color Doppler interrogation to evaluate venous filling patterns 1, 2
• Popliteal vein spectral Doppler on the symptomatic side 3

Why Not Limited Protocols

Limited protocols examining only proximal veins (CFV and popliteal) miss 30.3% of all DVTs, including isolated superficial femoral vein and calf DVTs, and require repeat scanning in 5-7 days to safely exclude propagating thrombus. 1, 4

Clinical Context Matters

Before ordering ultrasound, assess pretest probability using the Wells score:

• Low probability (<2) with negative high-sensitivity D-dimer: No ultrasound needed 1, 2
• Low probability with positive D-dimer OR moderate/high probability: Proceed directly to venous duplex ultrasound 1, 2
• In cancer patients: Skip D-dimer (high false-positive rate) and proceed directly to venous ultrasound 1, 5

Common Pitfalls to Avoid

• Don't confuse arterial and venous studies—DVT requires venous imaging, not arterial Doppler 1
• Don't accept limited proximal-only protocols as they miss isolated calf and SFV DVT requiring follow-up 1, 4
• Don't skip repeat imaging if symptoms persist or worsen despite negative initial study—repeat in 5-7 days or sooner 3, 2
• Don't rely on D-dimer in cancer patients—proceed directly to venous ultrasound 1, 5

Special Anatomic Considerations

For central veins poorly visualized by ultrasound:

• Whole-leg edema with normal compression ultrasound suggests iliocaval DVT requiring CT or MR venography 3, 2
• Upper extremity DVT in proximal subclavian, brachiocephalic, or SVC may require CT or MR venography 1, 5