Abstract:

The detection of atherosclerotic-related diseases in the early stages could potentially impact medical treatment in a cost-effective manner. Atherosclerosis is a common arterial disorder characterized by deposition of cholesterol, lipids, and cellular debris in the inner layers of large- and medium-sized arteries. As atherosclerotic deposition progresses, an area of narrowing, or stenosis, forms, resulting in reduced circulation to organs and other tissues supplied by the artery. When the stenoses become severe in critical arteries (e.g., the carotids or the coronaries) the result can be a catastrophic stroke or heart attack. In the early stages of the disease, the hemodynamics downstream of a stenosis become disturbed. The resulting flow disturbances produce characteristic features in Doppler ultrasound scans which are of diagnostic value. A technique has been investigated for extracting the streamwise turbulence intensity, or normalized velocity variance, using Doppler ultrasound in an arterial flow model. The model consists of a pump and 1.3-cm i.d. polyurethane tubing which is optically and acoustically transparent. Correlation between Doppler ultrasound and laser Doppler anemometry (LDA) measurements was examined in laminar as well as turbulent flow. Continuous flow has been employed initially and the work will be extended to pulsatile flow to replicate cardiac output.