What is the recommended initial imaging modality for varicose veins on the legs?

Duplex Ultrasound is the Recommended Initial Imaging Modality for Varicose Veins

Venous duplex ultrasonography is the gold standard initial imaging modality for the diagnosis and assessment of varicose veins in the legs. 1, 2

Benefits of Duplex Ultrasound for Varicose Veins

• Duplex ultrasound provides comprehensive assessment of both the anatomy and function of the venous system, allowing for analysis of venous compressibility and Doppler imaging of blood flow 1
• It can determine which saphenous junctions are incompetent, measure junction diameters, assess the extent of reflux, and locate incompetent perforating veins 2, 1
• It can simultaneously evaluate for acute or occult deep venous thrombosis and superficial thrombophlebitis, which may coexist with varicose veins 2, 1
• It is non-invasive, readily available, and does not require intravenous contrast agents 1
• It is relatively lower cost compared to other imaging modalities 1

Technical Aspects of Duplex Ultrasound Assessment

• Reflux is defined as retrograde flow duration of more than 350 milliseconds in perforating veins, more than 500 milliseconds in superficial and deep calf veins, and more than 1,000 milliseconds in femoropopliteal veins 2, 1
• The optimal technique involves the patient standing on one leg while the other leg is scanned, though alternatives like 60° Trendelenburg positioning may be used if standing is not tolerated 2
• Evaluation should include the deep venous system, great saphenous vein, small saphenous vein, and accessory saphenous veins 2, 3
• Assessment should be performed in both transverse and longitudinal planes 2

Alternative Imaging Modalities

• Other imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), venography, and plethysmography are used only if venous ultrasonography is inconclusive or for more complex surgical situations 2
• These alternative modalities may be considered in cases where:
  • Ultrasound imaging is limited or suboptimal 2
  • Characterization of pelvic veins is needed 2, 4
  • There is a need to avoid iodinated contrast 2
  • Complex variant venous anatomy is present 5

Limitations of Duplex Ultrasound

• Duplex ultrasound may have limitations in imaging more central veins such as pelvic veins 1
• It has historically shown lower sensitivity (40-63%) for detecting incompetent perforator veins compared to venography (83-90%) 6
• Results can be limited by bandages, casts, or pain 1
• The examination is operator-dependent, requiring skilled technicians for accurate results 1

Clinical Implications for Management

• The decision to proceed with treatment and the choice of treatment should be based on symptoms, patient preferences, and the findings from duplex ultrasound 2, 3
• Treatment considerations include the presence or absence of deep venous insufficiency and the specific characteristics of the affected veins 2
• For patients with severe venous disease or when interventional therapy is being considered, venous duplex ultrasonography provides essential information for treatment planning 3

Common Pitfalls to Avoid

• Relying solely on hand-held Doppler (HHD) ultrasonography is insufficient for planning varicose vein surgery, as it has limited sensitivity (73% at saphenofemoral junction, 77% at saphenopopliteal junction, and 51% for thigh perforators) 7
• Failing to perform duplex ultrasound before intervention could leave residual sites of reflux in approximately 24% of cases 7
• Not assessing for pelvic vein reflux in women with recurrent varicose veins or atypical varicosities 4

Duplex ultrasound has become the standard of care for the initial assessment of varicose veins, replacing more invasive techniques like venography while providing comprehensive anatomical and functional information to guide treatment decisions 4, 5.