Quantitative analysis of continuous-wave Doppler spectral broadening for the diagnosis of carotid disease: results of a multicenter study.

This article reports the results of a multicenter study that compares 333 frequency analysis studies with the continuous-wave Doppler method with angiography. With receiver operating characteristic curves, the study documents the accuracy of the Doppler technique for the diagnosis of extracranial carotid arterial stenosis greater than 45% diameter reduction. It confirms the accuracy of the measurement of the maximal peak Doppler frequency and, in addition, shows that quantitative analysis of the instantaneous Doppler spectrum at peak systole by the measurement of the spectral broadening index is of diagnostic value. Likelihood ratios have been calculated with the use of curve-fitting techniques and it has been demonstrated how both the peak frequency and the spectral broadening index can be used together to improve the certainty of diagnosis. It is concluded that the probability that an individual patient has significant carotid arterial disease can be determined with the measurements of peak frequency and spectral broadening index from the continuous-wave Doppler spectral waveform.