Efficacy of CW-Doppler and duplex system examinations for the evaluation of extracranial carotid disease.

The efficacy of different ultrasound methods for the detection of extracranial arterial disease (EAD) was evaluated on the basis of the comparison with angiography. High-resolution B-scan imaging combined with a multigated pulsed Doppler flow pattern analysis (Duplex system) achieved the best results for the detection of morphological and hemodynamic changes of nonstenotic lesions and low grade stenosis. However, a technically unsatisfactory examination rate of 19%, the failure to differentiate between total and subtotal carotid occlusions, underestimation of significant stenosis and impracticable vertebral flow studies were disadvantages of the Duplex technique. CW-Doppler examinations proved to be more precise and more reliable for the detection of significant stenosis and occlusions. Since vertebral blood flow studies were impractical with the Duplex system, CW-Doppler provides more comprehensive information about the hemodynamics of cerebral blood supply.