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Experimental Studies to Define the Geometry of the Flow Convergence Region

Shandas, Robin and Gharib, Morey and Liepmann, Dorian and Shiota, Takahiro and Sahn, David J. (1992) Experimental Studies to Define the Geometry of the Flow Convergence Region. Echocardiography, 9 (1). pp. 43-50. ISSN 0742-2822. doi:10.1111/j.1540-8175.1992.tb00438.x.

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The color flow convergence method for calculating volume flow through regurgitant or forward flow restrictive orifices has gained significant interest and a number of in vitro studies have suggested that this method is accurate, even in pulsatile models. Clinical application of the method over a wide range of conditions will require improved understanding of the effect of orifice size, flow geometry, and flow rate on the flow convergence geometry. In this study, we performed laser particle tracking investigations to allow visualization of streamlines into stenotic orifices. These streamlines are theoretically perpendicular to the isovelocity surfaces used for flow convergence calculations. We compared those observations to color flow map, flow convergence images obtained with a Toshiba 160A for orifices 5 to 15 mm^2 with flow rates of 1.5 to 9.7 L/min. Our results show that for large orifices, low flow rates, and/or low pressure gradients, more oblique streamlines in the velocity of the orifice correspond to nonhemispherical, but more elliptical, flow convergence geometries. This can be corrected for by using lower Nyquist limits and calculating flow convergence at greater distances from the orifice. Under high flow and high gradient conditions, increased Nyquist limits and shorter aliasing radii are more suitable. Our studies yield insights into flow convergence geometry and yield corrective procedures to improve volume flow calculation.

Item Type:Article
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URLURL TypeDescription DOIArticle
Alternate Title:Laser Doppler Particle Tracking and Color Doppler Imaging
Additional Information:© 1992 International Society of Cardiovascular Ultrasound. Supported in part by grant R01 HL 43287 from the National Heart, Lung, and Blood Institute.
Funding AgencyGrant Number
National Heart, Lung, and Blood InstituteRO1 HL 43287
Subject Keywords:color flow Doppler, in vitro fluid dynamics, flow convergence, regurgitant flow rate
Issue or Number:1
Record Number:CaltechAUTHORS:20130920-075015934
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Official Citation:SHANDAS, R., GHARIB, M., LIEPMANN, D., SHIOTA, T. and SAHN, D. J. (1992), Experimental Studies to Define the Geometry of the Flow Convergence Region: Laser Doppler Particle Tracking and Color Doppler Imaging. Echocardiography, 9: 43–50. doi: 10.1111/j.1540-8175.1992.tb00438.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41432
Deposited By: Tony Diaz
Deposited On:20 Sep 2013 19:35
Last Modified:10 Nov 2021 04:30

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