Abstract
Background Newer three-dimensional imaging technologies provide insight into cardiac shape and geometry from views previously unobtainable. Standard formulae like the continuity equation (CE) that rely on inherent assumptions about left ventricular outflow tract (LVOT) shape may need to be revisited. In the CE, small changes in LVOT diameter may significantly change calculated aortic valve area (AVA). Using 64-slice Multi-detector CT (MDCT), we performed LVOT planimetry to obviate the need for any geometric assumptions. Methods 64-slice MDCT was performed in 30 consecutive patients. The diameter-derived LVOT area (ALVOTdiam) was calculated from a view analogous to the 2D echo parasternal long axis. Direct planimetry of the LVOT (ALVOTplan) was performed just beneath the aortic valve in a plane perpendicular to the LVOT long axis. Further, assuming an ellipsoid outflow tract shape, LVOT area (ALVOTellip) was calculated using πab from the long and short diameters of the planimetered LVOT view. Eccentricity index (EI) was estimated by subtracting the ratio of shortest and longest LVOT diameters from one. Results ALVOTdiam always measured smaller than ALVOTplan (mean 3.7 ± 1.2 cm2 vs. 4.1 ± 1.3 cm2, respectively). The median EI was 0.18 (95% CI = 0.16–0.2; P = 0.0001). ALVOTellip more closely agreed with ALVOTplan (correlation = 0.96; P < 0.0001) than did ALVOTdiam (correlation = 0.87; P < 0.0001). Conclusion Using MDCT, the LVOT was shown to be elliptical in most patients. Applying the CE which assumes roundness of the LVOT consistently underestimated the LVOT area which may affect estimated AVA. Planimetry of the LVOT utilizing three-dimensional imaging modalities such as 3-D echocardiography, MRI, or MDCT may render a more precise AVA.
Similar content being viewed by others
References
Zoghbi WA, Farmer KL, Soto JG, Nelson JG, Quinones MA (1986) Accurate noninvasive quantification of stenotic valve area by Doppler echocardiography. Circulation 73:452–459
Teirstein P, Yeager M, Yock PG, Popp RL (1986) Doppler echocardiographic measurement of aortic valve area in aortic stenosis: a noninvasive application of the Gorlin formula. J Am Coll Cardiol 8:1059–1065
Bednarz JE, Krauss D, Lang RM (1996) An echocardiographic approach to the assessment of aortic stenosis. J Am Soc Echocardiogr 9:286–294. doi:10.1016/S0894-7317(96)90142-X
Carabello BA (2002) Aortic stenosis. N Engl J Med 346:677–682. doi:10.1056/NEJMcp010846
Otto CM (2004) Valvular stenosis. In: Otto CM (ed) Textbook of clinical echocardiography. Elsevier Saunders, Pennsylvania, pp 280–287
Doddamani S, Bello R, Friedman MA et al (2007) Demonstration of left ventricular outflow tract eccentricity by real time 3D-echocardiography: implications for determination of aortic valve area. Echocardiography 24:860–866. doi:10.1111/j.1540-8175.2007.00479.x
Tanaka K, Makaryus AN, Wolff SD (2007) Correlation of aortic valve area obtained by the velocity-encoded phase contrast continuity method to direct planimetry using cardiovascular magnetic resonance. J Cardiovasc Magn Reson 9:799–805. doi:10.1080/10976640701545479
Achenbach S, Ulzheimer S, Baum U et al (2000) Noninvasive coronary angiography by retrospectively ECG-gated multislice spiral CT. Circulation 102:2823–2828
Willmann JK, Weishaupt D, Lachat M et al (2002) Electrocardiographically gated multi-detector row CT for assessment of valvular morphology and calcification in aortic stenosis. Radiology 225:120–128. doi:10.1148/radiol.2251011703
Garcia D, Dumesnil JG, Durand LG, Kadem L, Pibarot P (2003) Discrepancies between catheter and Doppler estimates of valve effective orifice area can be predicted from the pressure recovery phenomenon: practical implications with regard to quantification of aortic stenosis severity. J Am Coll Cardiol 41:435–442. doi:10.1016/S0735-1097(02)02764-X
Wipperman CF, Schranz D, Stopfukuchen H, Huth R, Freund M, Jungst BK (1992) Evaluation of the valve area underestimation by the continuity equation. Cardiology 80:567–573
Oh JK, Taliercio CP, Holmes DR Jr (1988) Prediction of the severity of aortic stenosis by Doppler aortic valve area determination: prospective Doppler-catheterization correlation in 100 patients. J Am Coll Cardiol 11:1227–1234
Spevack DM, Almuti K, Ostfeld R et al (2008) Routine adjustment of Doppler echocardiographically derived aortic valve area using a previously derived equation to account for the effect of pressure recovery. J Am Soc Echocardiogr 21(1):34–37
Tsujino H, Jones M, Qin JX et al (2004) Combination of pulsed-wave Doppler and real-time three-dimensional color Doppler echocardiography for quantifying the stroke volume in the left ventricular outflow tract. Ultrasound Med Biol 30:1441–1446. doi:10.1016/j.ultrasmedbio.2004.08.027
Tsujino H, Jones M, Shiota T et al (2001) Real-time three-dimensional color Doppler echocardiography for characterizing the spatial velocity distribution and quantifying the peak flow rate in the left ventricular outflow tract. Ultrasound Med Biol 27:69–74. doi:10.1016/S0301-5629(00)00270-2
Menzel T, Mohr-Kahaly S, Wagner S, Fischer T, Bruckner A, Meyer J (1998) Calculation of left ventricular outflow tract area using three-dimensional echocardiography. Influence on quantification of aortic valve stenosis. Int J Card Imaging 14:373–379. doi:10.1023/A:1006045303442
Dall’Agata A, Cromme-Dijkhuis AH, Meijboom FJ et al (1999) Use of three-dimensional echocardiography for analysis of outflow obstruction in congenital heart disease. Am J Cardiol 83:921–925. doi:10.1016/S0002-9149(98)01061-3
Qui JX, Shiota T, Lever HM et al (2002) Impact of left ventricular outflow tract area on systolic outflow velocity in hypertrophic cardiomyopathy: a real-time three-dimensional echocardiographic study. J Am Coll Cardiol 39:308–314
Yalcin F, Shiota T, Odbashian J et al (2000) Comparison by real-time three-dimensional echocardiography of left ventricular geometry in hypertrophic cardiomyopathy versus secondary left ventricular hypertrophy. J Am Coll Cardiol 85:1035–1038
Paul JF, Abada HT (2007) Strategies for reduction of radiation dose in cardiac multi-slice CT. Eur Radiol 17:2028–2037. doi:10.1007/s00330-007-0584-3
Leschka S, Wildermuth S, Boehm T et al (2006) Noninvasive coronary angiography with 64-section CT: effect of average heart rate and heart rate variability on image quality. Radiology 241:378–385. doi:10.1148/radiol.2412051384
Herzog C, Arning-Erb M, Zangos S, Eichler K, Hammerstingl R, Dogan S et al (2006) Multi-detector row CT coronary angiography: influence of reconstruction technique and heart rate on image quality. Radiology 238(1):75–86. doi:10.1148/radiol.2381041595
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Doddamani, S., Grushko, M.J., Makaryus, A.N. et al. Demonstration of left ventricular outflow tract eccentricity by 64-slice multi-detector CT. Int J Cardiovasc Imaging 25, 175–181 (2009). https://doi.org/10.1007/s10554-008-9362-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10554-008-9362-9