Spectral analysis criteria in duplex scanning of aortoiliac and femoropopliteal arterial disease.

To validate the use of duplex scanning in the detection of lesions in the aortoiliac and femoropopliteal arteries, duplex scanning was prospectively compared to intra-arterial digital subtraction angiography in 61 patients with peripheral atherosclerotic disease. Based on a peak systolic velocity ratio greater than or equal to 2.5 or the absence of a Doppler signal, the overall sensitivity and specificity to detect lesions of greater than or equal to 50% diameter reduction was 84% and 96%, although some segments in the femoropopliteal arteries showed a sensitivity of only 60%-70%. Occlusions were detected with an overall sensitivity of 92% and specificity of 99%. The existence of a bi/triphasic Doppler signal, a window in the systolic spectral waveform and an end diastolic velocity greater than or equal to 60 cm/s has additional value in further grading of stenoses. This study shows that duplex scanning is highly comparable to angiography in the detection greater than or equal to 50% diameter reducing lesions in the aortoiliac arteries. Further evaluation is needed for the femoropopliteal arteries.