Duplex Doppler scanning and spectral bruit analysis for diagnosing carotid stenosis.

Spectral phonoangiography provides accurate quantitative noninvasive assessment of carotid stenosis, but only when a carotid bruit is present. Duplex Doppler ultrasound scanning permits imaging of the carotid bifurcation and qualitative assessment of the extent of carotid stenosis. Using these two methods and commercial equipment, we compared the noninvasive results with results of carotid angiograms performed within 2 weeks of the noninvasive studies. Of 299 vessels (common, internal and external carotid) assessed by both methods in 50 unselected patients, the noninvasive combination gave results correct to within 1 mm of the angiographic value in 95% of the vessels studied. These two noninvasive methods in combination allow diagnosis and follow-up of carotid stenosis with accuracy comparable to that of angiography in patients with and without carotid bruits.