Document Detail


Quantification of asymmetric valvular regurgitant jets by color Doppler ultrasound in vitro.
MedLine Citation:
PMID:  10148114     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Accurate quantification of regurgitant jets in natural and prosthetic heart valves has been a goal of health care workers and researchers for many years. One promising new method applies the law of conservation of momentum transfer to velocities measured by color Doppler ultrasound to calculate the flow rate in the jet. One complicating factor is that regurgitant jets from real heart valves may be highly asymmetric. The purpose of this investigation was to determine whether the accurate calculation of the flow rate in asymmetric jets imaged by color Doppler requires an asymmetric formulation of the conservation of momentum transfer, combined with a method for imaging the jet in three dimensions. Asymmetric jets issuing from narrow slits were imaged in an in vitro, steady flow system. The ultrasound transducer was rotated around the jet axis to image the jet in three dimensions. The three-dimensional imaging confirmed that jets from slits are indeed asymmetric, but become relatively axisymmetric far from the orifice. Images were analyzed by computer and the calculated flows compared to measured flows. The accuracy of an asymmetric formulation of the conservation of momentum transfer method was compared to a simpler, axisymmetric formulation. If axisymmetry was assumed in asymmetric jets, significant errors in the calculated flow rates occurred. In these cases, the calculated flow also varied widely with distance from the orifice. When asymmetry was taken into account, the errors were considerably reduced. The results suggest that, in asymmetric jets, the momentum transfer is convected around the jet axis.
Authors:
S F Stewart; F Burté; R E Clark
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Echocardiography (Mount Kisco, N.Y.)     Volume:  10     ISSN:  0742-2822     ISO Abbreviation:  Echocardiography     Publication Date:  1993 Jan 
Date Detail:
Created Date:  1993-04-22     Completed Date:  1993-04-22     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8511187     Medline TA:  Echocardiography     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  23-36     Citation Subset:  T    
Affiliation:
National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
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MeSH Terms
Descriptor/Qualifier:
Blood Flow Velocity
Echocardiography, Doppler / methods*
Heart Valve Diseases / ultrasonography
Heart Valve Prosthesis
Humans
Image Processing, Computer-Assisted / methods

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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