A comparison between two types of waveform analysis in patients with multisegmental arterial disease

The results of an experiment to compare two different methods of analysing ultrasound signals are presented. Normal volunteers, both young and old, and patients with arteriosclerosis were examined with Doppler shifted ultrasound and the results of two forms of waveform analysis retrospectively compared with angiograms. The angiograms were used to divide the patients into groups with similar patterns of disease. The ability of the two methods of analysis, 'pulsatility Index' (PI) and 'Laplace transform damping factor' (LTD), to identify patients with haemodynamically significant disease in the aorta or iliac arteries was tested statistically (Mann-Whitney U test) and compared in receiver operator curves. The results showed that both tests were equally good in the identification of aortoiliac disease, even when the superficial femoral artery was occluded, and that, contrary to theoretical arguments, LTD was influenced by distal impedance.