An anatomic source of false venous reflux with continuous wave Doppler.J Dermatol Surg Oncol. 1994 Oct; 20(10):676-8.JD
The limitations of continuous wave (CW) Doppler have been recognized in the assessment of venous reflux since CW Doppler is not able to distinguish reflux signals from more than one vein. In our experience, some regions with venous reflux suggested by CW Doppler were noted to have no reflux in any individual vein during duplex studies.
The aim of the study was to assess the anatomic source of the venous reflux suggested by CW Doppler but not confirmed by duplex ultrasound.
Five hundred and fifty-one consecutive lower limbs with primary or recurrent varicose veins were examined with CW Doppler and subsequently by color-coded duplex ultrasound to assess the source of venous reflux.
The duplex ultrasound study revealed no reflux in 44 specific regions (8%) where reflux had been indicated by CW Doppler. Two types of anatomy were noted. Two or more superficial veins joined the deep venous system via a common junction in 25 cases. A descending vein joined the deep venous system in 19 cases.
A bidirectional Doppler signal in a region of venous junction without any incompetent veins can be misinterpreted as venous reflux. A careful examination of veins not only at the region of the junction, but also at some distance down the stem of the vein is important during CW Doppler or duplex assessment.