Ultrasound in the study of atherosclerosis.

Ultrasound has come to play an increasingly important role in investigating atherosclerosis. The simple, continuous wave directional devices may be used to measure limb blood pressure and assess velocity patterns from accessible arteries. The recent combined B-mode and pulsed Doppler systems are being used regularly to study the carotid bifurcation in the neck. With improvements in image resolution, Doppler technology and signal processing methods, it is now feasible to evaluate the morphology of the plaque and accurately predict the degree of stenosis by the recorded velocity changes in the residual lumen. By the development of transducers of low transmitting frequency (less than 5 mHz), it is now possible to evaluate arteries at greater depth such as the renal and mesenteric vessels. Duplex scanning promises to become the definitive, noninvasive method of assessing both the anatomy and flow characteristics of all major arteries outside the thorax and skull that are common sites for the development of atherosclerosis.