The value of combined pulsed-Doppler and high-resolution real-time sonography of the extracranial carotid system.

Duplex carotid sonography (DCS) (high-resolution real-time with combined pulsed Doppler) was performed in 374 symptomatic patients. Biplane angiographic correlation was available in 172 extracranial carotid systems. Degree of stenosis was estimated by the Doppler spectrum and by real-time appearances and categorized as: normal; less than 10% diameter reduction; 10-49% diameter reduction; 50-99% diameter reduction; or occlusion. The overall accuracy of sonography was 88%. Normal arteries were identified with a specificity of 96% and a positive predictive value of 97%. Hemodynamically, significant lesions were differentiated from less severe disease with an accuracy of 95%, a positive predictive value of 87%, and a negative predictive value of 100%. Occlusions were identified with a sensitivity of 80% and a positive value of 91%. Duplex sonography is an accurate, noninvasive method of evaluating the extracranial carotid system.