Carotid artery stenosis--reassessment of the Doppler criteria.

Few previous studies of the accuracy of duplex Doppler in the assessment of carotid artery stenosis have looked at the accuracy in excluding disease in populations with a significant number of normal arteries. In addition, few studies have compared different criteria for stenosis. Duplex Doppler was used to evaluate the carotid arteries in 80 patients. Two well-described methods for analysing Doppler traces were used and the results were compared with those obtained from non-selective digital subtraction angiography. On the basis of these findings, the Doppler criteria used for carotid stenosis were redefined in terms of changes in peak velocity rather than Doppler frequency shift. Using these criteria, the sensitivity of Doppler in identifying carotid stenosis was 97% (98% sensitivity for greater than 50% stenosis) and specificity was increased from 84% to 93%.