Quantitative assessment of carotid artery disease by continuous wave and pulsed multigated Doppler--prospective comparison with angiography.

We have evaluated the use of a Doppler system combining continuous wave (CW) and pulsed multigated Doppler (PD) for quantification of internal carotid artery (ICA) stenoses. The peak systolic frequency (PF), obtained with the CW technique was used for identification of lesions exceeding 50% stenosis. Thereafter, with the PD technique, the spectral broadening index (SBI) was calculated from a sample volume located in the area of highest forward velocity (PD), and this SBI was used to discriminate normal from diseased vessels. Results were compared with arterial digital subtraction angiography. For assessment of greater than or equal to 50% stenoses we obtained an overall accuracy of PF (CW) of 90%. The use of SBI (PD) for discriminating normal from diseased vessels resulted in an accuracy of 86% (sensitivity 93%, specificity 74%). The combination of CW and PD achieved an overall agreement of 77% (kappa = 0.676 +/- 0.053). It is concluded that the combination of CW and pulsed multigated Doppler is accurate in the diagnosis of even minor ICA stenoses. For exclusion of disease, imaging combined with flow information seems necessary.