Skip to main content
NCBI home page
Heart logoLink to Heart
. 1998 Apr;79(4):324–330. doi: 10.1136/hrt.79.4.324

Determination of prestenotic flow volume using an automated method based on colour Doppler imaging for evaluating orifice area by the continuity equation: validation in a pulsatile flow model

K Dennig 1, H Nesser 1, D Hall 1, H Haase 1, A Schomig 1
PMCID: PMC1728670  PMID: 9616336

Abstract

Objective—To evaluate, in a pulsatile flow model simulating flow conditions in valvar stenoses, whether accurate determination of orifice area can be achieved by the continuity equation using automated determination of flow volumes based on spatiotemporal integration of digital colour Doppler flow velocities.
Methods—A method for automated determination of flow volumes which takes into account the velocity distribution across a region of interest was examined using flow through a tube and various restrictive outlet orifices with areas ranging between 0.2 and 3.1 cm2. The sampling rectangle of the Doppler method was positioned proximal to the obstructions within the flow convergence zone for evaluating prestenotic flow volume. Stenotic jet velocities were recorded by continuous wave Doppler to obtain the integral under the velocity curve. Prestenotic flow volume was then divided by the velocity integral to calculate functional orifice area according to the continuity equation.
Results—The presence of parabolically shaped velocity profiles across the prestenotic region was demonstrated by the Doppler method. Excellent agreement was found between prestenotic flow volumes measured by the Doppler technique and actual values (r = 0.99, SEE = 1.35 ml, y = 0.99x−0.24). Use of the continuity equation led to a close correlation, with a systematic underestimation of geometric orifice sizes. Correction of Doppler data for flow contraction yielded an excellent agreement with actual orifice areas.
Conclusions—The study validated the accuracy of a Doppler method for automated determination of flow volumes for quantifying orifice area by the continuity equation. Prestenotic flow volume and functional orifice area could be evaluated reliably in the presence of non-flat velocity profiles. Thus the method contributes to the non-invasive assessment of valvar stenoses.

 Keywords: Doppler echocardiography;  automated flow volume determination;  valvar stenoses;  pulsatile flow model

Full Text

The Full Text of this article is available as a PDF (159.6 KB).

Figure 1  .

Figure 1  

Open in a new tab

Schematic drawing of the pulsatile flow model. A computer (PC) controlled pump (P) cross checked by a flow meter (F) delivers flow volumes from a fluid reservoir (R) into a closed circulation. The test tube (T), at the outflow region of which various restrictive orifices can be inserted, is surrounded by a water tank (W) to improve ultrasound imaging conditions. Ultrasound recordings can be performed through a membrane against flow direction from the upper transducer position.

Figure 2  .

Figure 2  

Open in a new tab

The colour Doppler image on the right side shows a jet towards the transducer created by the insertion of a circular shaped orifice with a diameter of 0.8 cm and the orientation of the CW Doppler beam through the centre of the jet. On the left side are shown the corresponding temporal velocity profile resembling that of stenotic jets at the semilunar valves and the calculated integral under the velocity curve.

Figure 3  .

Figure 3  

Open in a new tab

Example of the application of the algorithm for automated determination of prestenotic flow volume from colour Doppler imaging using a volume of 50 ml through an orifice with a diameter of 0.8 cm. Flow toward the transducer, colour coded in red, is shown on the left panel with increasing flow velocities within the centre of the flow convergence zone close to the obstruction. The sampling rectangle of the automated method is positioned into the flow convergence zone and an instantaneous velocity profile across its diameter is depicted on the right sided graph as a parabolically shaped spatial profile. The panel on the right side shows the last colour Doppler image of the chosen flow interval and the calculated flow volume is depicted within the bar on the bottom of the image.

Figure 4  .

Figure 4  

Open in a new tab

Correlation of true flow volumes (FVt) and measured flow volumes by the Doppler technique (FVD) in the prestenotic region for the smaller orifice sizes with a diameter of 0.5 (circles), 0.8 (squares), and 1.0 cm (triangles). Mean values and standard deviation from five measurements are depicted.

Figure 5  .

Figure 5  

Open in a new tab

Measured flow volumes (ordinate) plotted against actual flow volumes (abscissa) for the larger orifice sizes with a diameter of 1.5 (circles) and 2.0 cm (squares). Mean values and standard deviations from five measurements are shown.

Figure 6  .

Figure 6  

Open in a new tab

Relation between true geometric orifice areas (OAt) and orifice areas calculated by the application of the continuity equation (OAD). Functional orifice areas (circles) determined from the Doppler parameters are closely correlated and systematically smaller than geometric areas. Correction of Doppler data (squares) for flow contraction behind the abrupt obstructions by the factor of 1.54 yielded a close agreement with actual orifice sizes.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Come P. C., Riley M. F., Ferguson J. F., Morgan J. P., McKay R. G. Prediction of severity of aortic stenosis: accuracy of multiple noninvasive parameters. Am J Med. 1988 Jul;85(1):29–37. doi: 10.1016/0002-9343(88)90499-8. [DOI] [PubMed] [Google Scholar]
  2. Dennig K., Kraus F., Rudolph W. Doppler-echokardiographische Bestimmung der Offnungsfläche bei Aortenklappenstenose unter Anwendung der Kontinuitätsgleichung. Herz. 1986 Dec;11(6):309–317. [PubMed] [Google Scholar]
  3. Derumeaux G., Bonnemains T., Remadi F., Cribier A., Letac B. Non-invasive assessment of mitral stenosis before and after percutaneous balloon mitral valvotomy by Doppler continuity equation. Eur Heart J. 1992 Aug;13(8):1034–1039. doi: 10.1093/oxfordjournals.eurheartj.a060310. [DOI] [PubMed] [Google Scholar]
  4. Dittmann H., Voelker W., Karsch K. R., Seipel L. Influence of sampling site and flow area on cardiac output measurements by Doppler echocardiography. J Am Coll Cardiol. 1987 Oct;10(4):818–823. doi: 10.1016/s0735-1097(87)80275-9. [DOI] [PubMed] [Google Scholar]
  5. Ferguson J. J. American College of Cardiology 45th Annual Scientific Session, Orlando, Florida, March 24 to 27, 1996. Circulation. 1996 Jul 1;94(1):1–5. doi: 10.1161/01.cir.94.1.1. [DOI] [PubMed] [Google Scholar]
  6. Grayburn P. A., Smith M. D., Harrison M. R., Gurley J. C., DeMaria A. N. Pivotal role of aortic valve area calculation by the continuity equation for Doppler assessment of aortic stenosis in patients with combined aortic stenosis and regurgitation. Am J Cardiol. 1988 Feb 1;61(4):376–381. doi: 10.1016/0002-9149(88)90948-4. [DOI] [PubMed] [Google Scholar]
  7. Harrison M. R., Gurley J. C., Smith M. D., Grayburn P. A., DeMaria A. N. A practical application of Doppler echocardiography for the assessment of severity of aortic stenosis. Am Heart J. 1988 Mar;115(3):622–628. doi: 10.1016/0002-8703(88)90813-7. [DOI] [PubMed] [Google Scholar]
  8. Ihlen H., Amlie J. P., Dale J., Forfang K., Nitter-Hauge S., Otterstad J. E., Simonsen S., Myhre E. Determination of cardiac output by Doppler echocardiography. Br Heart J. 1984 Jan;51(1):54–60. doi: 10.1136/hrt.51.1.54. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Karp K., Teien D., Eriksson P. Doppler echocardiographic assessment of the valve area in patients with atrioventricular valve stenosis by application of the continuity equation. J Intern Med. 1989 Apr;225(4):261–266. doi: 10.1111/j.1365-2796.1989.tb00076.x. [DOI] [PubMed] [Google Scholar]
  10. Kupari M., Koskinen P. Systolic flow velocity profile in the left ventricular outflow tract in persons free of heart disease. Am J Cardiol. 1993 Nov 15;72(15):1172–1178. doi: 10.1016/0002-9149(93)90989-p. [DOI] [PubMed] [Google Scholar]
  11. Labovitz A. J., Buckingham T. A., Habermehl K., Nelson J., Kennedy H. L., Williams G. A. The effects of sampling site on the two-dimensional echo-Doppler determination of cardiac output. Am Heart J. 1985 Feb;109(2):327–332. doi: 10.1016/0002-8703(85)90602-7. [DOI] [PubMed] [Google Scholar]
  12. Lewis J. F., Kuo L. C., Nelson J. G., Limacher M. C., Quinones M. A. Pulsed Doppler echocardiographic determination of stroke volume and cardiac output: clinical validation of two new methods using the apical window. Circulation. 1984 Sep;70(3):425–431. doi: 10.1161/01.cir.70.3.425. [DOI] [PubMed] [Google Scholar]
  13. Loeppky J. A., Hoekenga D. E., Greene E. R., Luft U. C. Comparison of noninvasive pulsed Doppler and Fick measurements of stroke volume in cardiac patients. Am Heart J. 1984 Feb;107(2):339–346. doi: 10.1016/0002-8703(84)90384-3. [DOI] [PubMed] [Google Scholar]
  14. Nakatani S., Masuyama T., Kodama K., Kitabatake A., Fujii K., Kamada T. Value and limitations of Doppler echocardiography in the quantification of stenotic mitral valve area: comparison of the pressure half-time and the continuity equation methods. Circulation. 1988 Jan;77(1):78–85. doi: 10.1161/01.cir.77.1.78. [DOI] [PubMed] [Google Scholar]
  15. Nicolosi G. L., Pungercic E., Cervesato E., Pavan D., Modena L., Moro E., Dall'Aglio V., Zanuttini D. Feasibility and variability of six methods for the echocardiographic and Doppler determination of cardiac output. Br Heart J. 1988 Mar;59(3):299–303. doi: 10.1136/hrt.59.3.299. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Oh J. K., Taliercio C. P., Holmes D. R., Jr, Reeder G. S., Bailey K. R., Seward J. B., Tajik A. J. Prediction of the severity of aortic stenosis by Doppler aortic valve area determination: prospective Doppler-catheterization correlation in 100 patients. J Am Coll Cardiol. 1988 Jun;11(6):1227–1234. doi: 10.1016/0735-1097(88)90286-0. [DOI] [PubMed] [Google Scholar]
  17. Ormiston J. A., Shah P. M., Tei C., Wong M. Size and motion of the mitral valve annulus in man. I. A two-dimensional echocardiographic method and findings in normal subjects. Circulation. 1981 Jul;64(1):113–120. doi: 10.1161/01.cir.64.1.113. [DOI] [PubMed] [Google Scholar]
  18. Pu M., Griffin B. P., Vandervoort P. M., Leung D. Y., Cosgrove D. M., 3rd, Thomas J. D. Intraoperative validation of mitral inflow determination by transesophageal echocardiography: comparison of single-plane, biplane and thermodilution techniques. J Am Coll Cardiol. 1995 Oct;26(4):1047–1053. doi: 10.1016/0735-1097(95)00259-2. [DOI] [PubMed] [Google Scholar]
  19. Rossvoll O., Samstad S., Torp H. G., Linker D. T., Skjaerpe T., Angelsen B. A., Hatle L. The velocity distribution in the aortic anulus in normal subjects: a quantitative analysis of two-dimensional Doppler flow maps. J Am Soc Echocardiogr. 1991 Jul-Aug;4(4):367–378. doi: 10.1016/s0894-7317(14)80447-1. [DOI] [PubMed] [Google Scholar]
  20. Samstad S. O., Rossvoll O., Torp H. G., Skjaerpe T., Hatle L. Cross-sectional early mitral flow-velocity profiles from color Doppler in patients with mitral valve disease. Circulation. 1992 Sep;86(3):748–755. doi: 10.1161/01.cir.86.3.748. [DOI] [PubMed] [Google Scholar]
  21. Samstad S. O., Torp H. G., Linker D. T., Rossvoll O., Skjaerpe T., Johansen E., Kristoffersen K., Angelsen B. A., Hatle L. Cross sectional early mitral flow velocity profiles from colour Doppler. Br Heart J. 1989 Sep;62(3):177–184. doi: 10.1136/hrt.62.3.177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Skjaerpe T., Hegrenaes L., Hatle L. Noninvasive estimation of valve area in patients with aortic stenosis by Doppler ultrasound and two-dimensional echocardiography. Circulation. 1985 Oct;72(4):810–818. doi: 10.1161/01.cir.72.4.810. [DOI] [PubMed] [Google Scholar]
  23. Stewart W. J., Jiang L., Mich R., Pandian N., Guerrero J. L., Weyman A. E. Variable effects of changes in flow rate through the aortic, pulmonary and mitral valves on valve area and flow velocity: impact on quantitative Doppler flow calculations. J Am Coll Cardiol. 1985 Sep;6(3):653–662. doi: 10.1016/s0735-1097(85)80127-3. [DOI] [PubMed] [Google Scholar]
  24. Sun J. P., Pu M., Fouad F. M., Christian R., Stewart W. J., Thomas J. D. Automated cardiac output measurement by spatiotemporal integration of color Doppler data. In vitro and clinical validation. Circulation. 1997 Feb 18;95(4):932–939. doi: 10.1161/01.cir.95.4.932. [DOI] [PubMed] [Google Scholar]
  25. Teirstein P., Yeager M., Yock P. G., Popp R. L. Doppler echocardiographic measurement of aortic valve area in aortic stenosis: a noninvasive application of the Gorlin formula. J Am Coll Cardiol. 1986 Nov;8(5):1059–1065. doi: 10.1016/s0735-1097(86)80382-5. [DOI] [PubMed] [Google Scholar]
  26. Tsujino H., Shiki E., Hirama M., Iinuma K. Quantitative measurement of volume flow rate (cardiac output) by the multibeam Doppler method. J Am Soc Echocardiogr. 1995 Sep-Oct;8(5 Pt 1):621–630. doi: 10.1016/s0894-7317(05)80375-x. [DOI] [PubMed] [Google Scholar]
  27. Wiseth R., Samstad S., Rossvoll O., Torp H. G., Skjaerpe T., Hatle L. Cross-sectional left ventricular outflow tract velocities before and after aortic valve replacement: a comparative study with two-dimensional Doppler ultrasound. J Am Soc Echocardiogr. 1993 May-Jun;6(3 Pt 1):279–285. doi: 10.1016/s0894-7317(14)80064-3. [DOI] [PubMed] [Google Scholar]
  28. Zhou Y. Q., Faerestrand S., Matre K. Velocity distributions in the left ventricular outflow tract in patients with valvular aortic stenosis. Effect on the measurement of aortic valve area by using the continuity equation. Eur Heart J. 1995 Mar;16(3):383–393. doi: 10.1093/oxfordjournals.eurheartj.a060922. [DOI] [PubMed] [Google Scholar]
  29. Zoghbi W. A., Farmer K. L., Soto J. G., Nelson J. G., Quinones M. A. Accurate noninvasive quantification of stenotic aortic valve area by Doppler echocardiography. Circulation. 1986 Mar;73(3):452–459. doi: 10.1161/01.cir.73.3.452. [DOI] [PubMed] [Google Scholar]

Articles from Heart are provided here courtesy of BMJ Publishing Group

RESOURCES