Advancements in technology have brought noninvasive diagnosis of cerebrovascular disease to a high level of accuracy in a relatively short period of time. Conventional duplex sonography allows precise vessel localization and Doppler quantification. The further refinement of color flow imaging promises to simplify the examination and add considerable confidence to the diagnosis. Regardless of the technology used, ultrasound evaluation of the carotid arteries remains a difficult examination to perform, and excellent results are only possible with meticulous technique. The astute sonographer or sonologist will use all aspects of available ultrasound technology to the fullest. Careful evaluation of a seemingly overwhelming array of parameters will result in an impressive degree of diagnostic accuracy.