Standardization of Carotid Ultrasound

carotid diameter and the intrastenotic velocity/distal velocity ratio will underestimate the degree of stenosis when the distal carotid diameter is reduced.With the NASCET method, such lesions are classified angiographically as 95%. 2 Classification as reduced or not reduced is sometimes difficult and can lead to observer variability with use of the NASCET stenosis definition.4 In 1979, Spencer and Reid 1 first described reduced Doppler frequencies downstream to a tight stenosis.Carotid Doppler offers the opportunity for hemodynamic analysis.Evaluation of downstream velocity together with the velocity ratio could increase diagnostic accuracy in preocclusive stenoses with reduced flow.In our study, a mean velocity ratio Ͼ10 in combination with a mean velocity Ͻ0.26 m/s in the high cervical carotid artery increases sensitivity for detection of Ͼ90% stenosis to 100% with a specificity of 90%.The 95% confidence interval for the correlation of angiographic stenosis with predicted stenosis values using the mean velocity ratio (Figure 1 in our article) is plotted in Figure 2.