Experience in colour-flow duplex carotid imaging for extracranial carotid stenosis

Abstract

Carotid duplex scanning is a non-invasive, cost-effective method for the diagnosis of stability, progression or improvement of extracranial cerebral disease. It yields functional information that complements the anatomic information provided by angiography. It can localize the disease with B-mode ultrasound and can determine the functional severity of the disease with spectral analysis and colour-flow imaging. The diagnostic criteria are based on the peak systolic velocity and end diastolic velocity of the internal carotid artery. Carotid stenosis of 70% or greater is taken as significant. The texture and morphology of the plaque can be reported as either homogeneous, heterogeneous with ulceration or heterogeneous without ulceration. This distinction would not be detected readily by angiography. With a high degree of accuracy in identifying sig-nificant stenoses in carotid arteries, duplex scanning can replace angiography prior to performing carotid endarterectomy.