Preoperative continuous-wave Doppler spectral analysis was used to generate two parameters, peak frequency in the internal carotid artery (f(max)) and the ratio of peak frequencies in the internal and common carotid arteries (carotid index). These were compared with direct measurement of residual lumen diameter in pathologic specimens obtained from carotid endarterectomy in 37 patients. Doppler shift frequency parameters were well correlated with residual lumen diameter when the latter was at least 1 mm. Residual lumens of ≤2 mm were found to have an f(max) of <7.5 kHz and a carotid index of >3.8. If f(max) was >14 kHz or the carotid index was >7, the residual lumen diameter was nearly always ≤1 mm. Thus, the severity of the stenosis correlated directly with Doppler shift frequencies. The length of stenoses did not affect the correlations.
- Carotid artery diseases
ASJC Scopus subject areas
- Clinical Neurology
- Cardiology and Cardiovascular Medicine
- Advanced and Specialized Nursing