The role of pulse-wave Doppler sonography in quantifying internal carotid stenosis

To determine the accuracy of pulse-wave Doppler (PWD) sonography in quantifying cervical internal carotid artery (ICA) stenosis, we compared results of PWD with conventional digital subtraction angiography (DSA). A total of 202 carotid arteries were evaluated by means of these two techniques. The patients were divided into four groups according to the percentage of angiographic carotid stenosis as suggested by NASCET. A mathematic model of quadratic relationship between DSA stenosis and blood flow velocity, recorded by PWD, was worked out; peak systolic velocity and mean velocity values, corresponding to 70% DSA stenosis, were employed as key values to check PWD ability to detect high-grade stenosis. Finally, for each case, the correlation between the two techniques was evaluated. PWD well correlates with DSA, making it possible to detect and correctly quantify high-grade ( > 70%) ICA stenosis. In 4 cases with moderate ICA stenoses, blood flow velocity values were over the key values: in cases of moderate angiographic ICA stenosis, PWD identifies those patients in whom the haemodynamic pattern is comparable to the higher group, providing further matter for discussion in order to define surgical selection criteria.