Doppler Ultrasound of Lower Extremity Veins: Examination Protocol and Report Structure

Indications and Examination Technique

Typical indications include varicose veins, heaviness in the calf, and evening edema. A linear transducer of 7–12 MHz is used. The examination is conducted in a vertical position. Provocative maneuvers include the Valsalva maneuver for the sapheno-femoral junction (SFJ) and distal compression with release for trunks, tributaries, and perforators.

How to Properly Induce Reflux

The main task of duplex ultrasound in chronic venous insufficiency is not just to visualize reflux but to correctly provoke it, measure the duration of retrograde flow, determine the source, and describe it in CEAP terms. Without provocation, an incompetent valve may be missed.

Reflux is assessed standing on a venous platform (weight on the healthy leg) or sitting with legs dangling; lying down is unacceptable. The sample volume is set 1–2 cm distal to the valve, angle <60°, low filter.

Provocative Maneuvers

The Valsalva maneuver is performed on all patients: deep breath and straining for 2–3 s (~40 mmHg); the duration of retrograde flow is recorded from the start of straining to its cessation. Weak Valsalva or excessive probe pressure leads to underestimation of reflux.

Distal augmentation: the gold standard is the rapid augmentation system (cuff distal to the segment, 80–120 mmHg, deflation ~300 ms), standardizes pressure and provides reverse flow ≥30 cm/s. In the absence of a cuff, the Parana maneuver (body oscillation/dorsiflexion) is used.

Errors Leading to False-Negative Results

Underestimation of reflux is caused by: too weak or short straining (valve not loaded), performing while lying down (no hydrostatic column), excessive probe pressure (mechanically closes the lumen), late recording start. If the maneuver is weak, repeat sitting/standing, achieving adequate straining. In case of contraindications (severe CAD, recent abdominal surgery, hernias), alternative maneuvers are used.

Example of Descriptive Part

Left GSV in the saphenous compartment: diameter 6.9 mm (mid-thigh), 10.2 mm (knee level) — trunk dilation; reflux 1.1 s (standing, distal augmentation). SFJ: Valsalva maneuver — reflux 0.7 s (terminal valve incompetence). Anterior saphenous vein (ASV): diameter 3.0 mm, own 'saphenous eye', no reflux (healthy trunk).

Structure of the Conclusion

The conclusion is formulated based on the source and axial extent of reflux, duration of retrograde flow, condition of the deep system and perforators, followed by CEAP classification.

Example: “Primary axial reflux in the great saphenous vein from the sapheno-femoral junction to the knee level (t = 1.1 s) with terminal valve incompetence of SFJ (Valsalva 0.7 s) and trunk dilation; incompetent perforator in the mid-calf (4.1 mm, reflux 0.8 s), feeding varicosities of the medial calf. Deep system is competent. Anterior saphenous vein is intact. CEAP: C3, s; Ep; As (GSV thigh), Ap; Pr.”

Recommendations in the Conclusion

Example recommendations: consultation with a phlebologist to decide on GSV thermoablation (considering areas <5 mm from the skin) and strategy regarding the perforator; compression therapy. Modern varicose vein treatment involves minimally invasive trunk obliteration: thermal (endovenous laser or radiofrequency ablation), adhesive (cyanoacrylate, VenaSeal), and chemical (foam sclerotherapy).

Differentiation of Acute and Chronic Processes

The Society of Radiologists in Ultrasound (SRU) at a consensus conference (Needleman L. et al., Circulation, 2018) proposed classifying ultrasound findings into one of three categories: acute venous thrombosis (fresh process), chronic post-thrombotic changes (recanalization, synechiae, wall thickening, collaterals), and equivocal, when the findings do not allow confident classification as acute or chronic.