Background. The purpose of this study was to compare the abilities of segmental Doppler pressures (SDP) and color duplex imaging (CDI) to localize arterial stenosis and to assess the ability of CDI to accurately categorize the severity of disease. Methods. We analyzed 134 patients (268 limbs) who underwent all three tests; SDP, CDI, and arteriograms. Results of SDP and CDI were examined to determine their accuracy in localizing high grade (greater than 50%) stenosis at three levels; aortoiliac-common femoral artery (level I), superficial femoral artery (SFA; level II) and popliteal artery (level III). Results. The sensitivity, specificity, positive and negative predictive values, and overall accuracy for SDP and CDI were as follows: level I, 63%, 88%, 81%, 75%, and 77%; 93%, 99%, 98%, 95%, and 96%, respectively (p < 0.01); level II, 51%, 99%, 99%, 57%, and 70%, 94%, 98%, 99%, 92%, and 96%, respectively (p < 0.01); level III, 55%, 92%, 60%, 90%, and 85%; 78%, 100%, 97%, 95%, and 95%, respectively (p < 0.01). Exact agreement was noted between the CDI and arteriogram in regard to the severity of disease in 88% of the limbs (1170 segments). The presence of SFA disease in patients with level I disease or aortoiliac-common femoral artery disease in patients with level II disease did not significantly alter the ability of SDP to localize the disease. The presence of diabetes significantly affected the accuracy of SDP in localizing SFA and popliteal artery stenosis. An analysis of SDP's ability to detect any segment as abnormal, as confirmed by arteriogram, revealed a sensitivity of 88%, specificity of 82%, positive predictive value of 96%, negative predictive value of 60%, and overall accuracy of 87%. The average cost was $149 for an SDP and $472 for a CDI. Conclusions. CDI is superior to SDP in localizing arterial stenosis at all levels. However, because SDP is cheaper it can be used initially if no surgical or endovascular intervention is planned.
