Carotid Ultrasound.

Doppler ultrasound (US) is the primary noninvasive imaging modality for detecting, grading, and monitoring extracranial internal carotid artery (ICA) stenosis, which is a well-established surrogate marker for stroke risk. In addition, Doppler US is the primary imaging modality for surveillance of patients following carotid intervention with endarterectomy or stent placement. This article reviews the pathophysiology and epidemiology of stroke, technique for performing a carotid US examination, normal findings, and diagnostic US criteria for evaluating carotid plaque, grading stenosis in the native ICA and following intervention, as well as waveform analysis of the carotid arteries.