The effect of adjacent segment disease on the accuracy of colour duplex scanning for the diagnosis of lower limb arterial disease.

Abstract

To assess the effect of multisegment disease upon the accuracy of lower limb colour Duplex scanning. Prospective, semi-blind study. Vascular Laboratory and Radiology Department, University Hospital. A total of 148 limbs (1106 individual arterial segments) were examined from the distal aorta to the origins of the tibial arteries by colour-coded Duplex and arteriography. Individual segments were graded as 0-49%, 50-99% diameter reduced or occluded on the basis of peak systolic velocity ratios < 2.0, > or = 2.0 or an absent Doppler signal, and compared with similarly graded segments from blinded angiographic studies. The agreement (Kappa analysis) between Duplex and arteriography in segments adjacent to at least one proximal or distal > or = 50% diameter reducing lesion was then compared to the agreement between segments free of adjacent disease. For isolated areas of disease, the kappa value (95% confidence interval) of agreement between Duplex ultrasonography and arteriography was 0.63 (0.53-0.73) and in the presence of neighbouring disease the value was 0.78 (0.73-0.83). We conclude therefore that providing appropriate criteria are used, Duplex assessment of lower limb arterial disease is not adversely affected by adjacent disease.