Is Doppler ultrasound used for arterial or venous (Deep Vein Thrombosis) assessment?

Doppler Ultrasound for DVT Assessment is Primarily Venous, Not Arterial

Doppler ultrasound for Deep Vein Thrombosis (DVT) assessment is specifically designed to evaluate the venous system, not the arterial system. According to the Society of Radiologists in Ultrasound consensus guidelines, Complete Duplex Ultrasound (CDUS) is the preferred venous ultrasound test for diagnosing DVT 1.

Components of DVT Ultrasound Assessment

Standard Protocol

• Complete Duplex Ultrasound (CDUS) is the gold standard approach which includes:
  • Compression ultrasound of deep veins from inguinal ligament to ankle
  • Evaluation of posterior tibial and peroneal veins in the calf
  • Right and left common femoral vein spectral Doppler waveforms (to evaluate symmetry)
  • Popliteal spectral Doppler
  • Color Doppler imaging
  • Compression performed at 2-cm intervals 1

Key Diagnostic Principles

• Primary diagnostic technique: Vein compressibility assessment
  • Normal veins fully collapse with external pressure
  • DVT is diagnosed when veins fail to compress completely
• Secondary diagnostic features:
  • Visualization of echogenic material (thrombus) within the vein
  • Altered blood flow patterns detected by Doppler 1

Types of Venous Ultrasound Protocols

Several protocols exist with varying degrees of comprehensiveness:

1. Complete Duplex Ultrasound (CDUS) - most comprehensive approach
2. Complete Compression Ultrasound (CCUS) - compression from common femoral vein to ankle
3. Extended Compression Ultrasound (ECUS) - compression from common femoral vein to popliteal vein
4. 2-region Compression Ultrasound (2-CUS) - limited to femoral and popliteal regions 1

Important Clinical Considerations

• Limited protocols that don't include calf veins require a second study in 5-7 days to safely exclude DVT 1
• Point-of-care ultrasound with limited evaluation (ECUS) is appropriate when CDUS is not available, but requires follow-up CDUS in 5-7 days 1
• Symptomatic areas should always be evaluated, even if standard assessment of deep veins is normal 1

Common Pitfalls to Avoid

• Using arterial Doppler techniques: Arterial studies focus on different parameters and will miss venous pathology
• Limited protocols without follow-up: Limited examinations that don't include calf veins require follow-up studies
• Ignoring clinical probability: High clinical suspicion may warrant additional imaging despite negative initial tests 2
• External compression factors: Can cause false-positive results by mimicking non-compressible veins 3

Special Situations

• For suspected iliocaval DVT (proximal to standard ultrasound visualization), CT venography or MR venography should be considered 2
• Abnormal spectral Doppler waveforms should prompt pelvic imaging 2
• Whole-leg swelling with normal compression ultrasound suggests iliocaval DVT requiring advanced imaging 2

In summary, DVT assessment using Doppler ultrasound is fundamentally a venous study, not an arterial one. The complete duplex ultrasound protocol examining the venous system from groin to ankle is the preferred approach for accurate diagnosis and patient safety.