Cross-sectional vascular blood flow shear rate using Do

摘要

Abstract: Shear rate has been linked to various arterial wall properties and diseases such as cell function, neointimal hyperplasia, post-stenotic dilation and progression of atherosclerotic plaque. An accurate noninvasive method of measuring blood flow near the arterial wall is needed to allow the study of wall shear rate in humans to progress. Current clinical vascular laboratories are limited to using the Hagen-Poiseuille formulation based on steady laminar flow through a rigid- walled tube, which is not realized in vivo. This project used data collected with an ultrasound scanner to approximate the magnitude of wall shear rate in two dimensions using the formal definition of the velocity gradient in a radial direction. Blood flow was measured in the common carotid artery of 20 subjects in both longitudinal and transverse directions. The results showed that the wall shear rate was a factor of approximately 1.5 to 2 times greater than the value calculated using the Hagen-Poiseuille formulation. A comparison of the longitudinal and transverse estimation methods showed very similar values for all of the calculated quantities. This comparison contributed to the conclusion that this image-based technique provides a more accurate assessment of wall shear rate, with the significant addition of a second dimension for analysis. !21