Spectral analysis with digital presentation of C-W Doppler signals in the evaluation of carotid stenosis.
Using a continuous-wave ultrasound Doppler system with spectral analysis (FFT) and digital processing and presentation, the Doppler shift characteristics of the carotid arteries were studied in 40 healthy subjects (20 men and 20 women; average age 69 years). The reference values, thus obtained, were applied to the analysis of sonograms from 46 carotid arteries, which were also studied angiographically. Stenoses which reduced the diameter of the internal carotid artery by more than 30% could be identified with a sensitivity of 97% and a specificity of 100%. The results extend previous experience that spectral analysis improves the usefulness of the ultrasound Doppler system in the evaluation of carotid artery disease. The addition of digital processing and presentation of the Doppler shift characteristics increases the diagnostic precision and provides a permanent record. The importance of well-trained sonographers and adequate reference values is emphasized.