The impact of Duplex scanning on the evaluation of patients with asymptomatic bruits in the region of the carotid arteries.

Between January 1980 and January 1981, 95 patients with 'asymptomatic' bruits in the region of the carotid arteries were evaluated at the University of Washington with an ultrasonic Duplex scanner combined with spectral analysis. Based upon the interpretation of a hardcopy of the spectral analysis, the artery of interest was classified into one of five categories: A normal; B 5-15% diameter reduction; C 16-49% diameter reduction; D 50-99% diameter reduction, and E total occlusion. Forty-eight patients had unilateral and 47 patients had bilateral bruits; 142 bruits were evaluated. The distribution of disease in the internal carotid artery was: A: 2% (3/142); B: 30% (42/142); C: 37% (53/142); D: 29% (41/142), and E: 2% (3/142). If the presence of a high grade stenosis of the internal carotid artery (50-99% diameter reduction) is an indication for invasive intervention, then 71% of these patients would not require contrast arteriography. The role of a direct ultrasonic study, such as Duplex scanning, in patients with asymptomatic bruits is discussed.