Abstract
BACKGROUND--The idea that blood passes through the left ventricular outflow tract with a flat velocity profile has recently been questioned. OBJECTIVE--To construct flow velocity profiles by magnetic resonance imaging over the whole cross sectional subaortic flow area in normal subjects. SUBJECTS--Nine people without heart disease aged 25 to 56. DESIGN--Cardiac gated cine magnetic resonance images were produced with a 1.0 T magnet perpendicular to the longitudinal axis of the left ventricular outflow tract 0.5 to 1.0 cm below the aortic annulus in mid-systole. Velocity was encoded every 30-40 ms throughout systole in the direction of flow perpendicular to the image plane. MAIN OUTCOME MEASURES--Systolic velocity-time curves reconstructed in nine different regions (area of each circle 0.2 cm2) of the subaortic flow area. The systolic peak velocity and the mean flow rate were taken as indices of regional flow. RESULTS--The spatial inhomogeneity of the peak velocity, calculated as the percentage ratio of the range of the regional measurements to their mean, averaged 18.2% (5.0%), and the inhomogeneity of the mean flow rate was 19.2% (3.5%). There were significant trends (P < 0.05) across the regional measurements towards highest peak velocities and mean systolic flow rate in the anteromedial sector of the subaortic flow area. The peak systolic velocity in the centre of the flow area averaged 98 (8) cm/s while the coincident spatial average was 94 (5) cm (P = 0.013). CONCLUSIONS--The distribution of systolic velocities across the left ventricular outflow tract is skewed towards fastest flow in the anteromedial sector of the flow area. The peak velocities measured in the centre of the flow area slightly overestimate the coincident spatial average velocities.
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- Firmin D. N., Nayler G. L., Klipstein R. H., Underwood S. R., Rees R. S., Longmore D. B. In vivo validation of MR velocity imaging. J Comput Assist Tomogr. 1987 Sep-Oct;11(5):751–756. doi: 10.1097/00004728-198709000-00001. [DOI] [PubMed] [Google Scholar]
- Klipstein R. H., Firmin D. N., Underwood S. R., Rees R. S., Longmore D. B. Blood flow patterns in the human aorta studied by magnetic resonance. Br Heart J. 1987 Oct;58(4):316–323. doi: 10.1136/hrt.58.4.316. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kondo C., Caputo G. R., Masui T., Foster E., O'Sullivan M., Stulbarg M. S., Golden J., Catterjee K., Higgins C. B. Pulmonary hypertension: pulmonary flow quantification and flow profile analysis with velocity-encoded cine MR imaging. Radiology. 1992 Jun;183(3):751–758. doi: 10.1148/radiology.183.3.1584932. [DOI] [PubMed] [Google Scholar]
- 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]
- 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]
- Maier S. E., Meier D., Boesiger P., Moser U. T., Vieli A. Human abdominal aorta: comparative measurements of blood flow with MR imaging and multigated Doppler US. Radiology. 1989 May;171(2):487–492. doi: 10.1148/radiology.171.2.2649924. [DOI] [PubMed] [Google Scholar]
- Mathison M., Furuse A., Asano K. Doppler analysis of flow velocity profile at the aortic root. J Am Coll Cardiol. 1988 Oct;12(4):947–954. doi: 10.1016/0735-1097(88)90460-3. [DOI] [PubMed] [Google Scholar]
- Meier D., Maier S., Bösiger P. Quantitative flow measurements on phantoms and on blood vessels with MR. Magn Reson Med. 1988 Sep;8(1):25–34. doi: 10.1002/mrm.1910080104. [DOI] [PubMed] [Google Scholar]
- Mohiaddin R. H., Longmore D. B. Functional aspects of cardiovascular nuclear magnetic resonance imaging. Techniques and application. Circulation. 1993 Jul;88(1):264–281. doi: 10.1161/01.cir.88.1.264. [DOI] [PubMed] [Google Scholar]
- Nayler G. L., Firmin D. N., Longmore D. B. Blood flow imaging by cine magnetic resonance. J Comput Assist Tomogr. 1986 Sep-Oct;10(5):715–722. doi: 10.1097/00004728-198609000-00001. [DOI] [PubMed] [Google Scholar]
- 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]
- 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]
- 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]
- 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]
- Søndergaard L., Lindvig K., Hildebrandt P., Thomsen C., Ståhlberg F., Joen T., Henriksen O. Quantification of aortic regurgitation by magnetic resonance velocity mapping. Am Heart J. 1993 Apr;125(4):1081–1090. doi: 10.1016/0002-8703(93)90117-r. [DOI] [PubMed] [Google Scholar]
- Walker M. F., Souza S. P., Dumoulin C. L. Quantitative flow measurement in phase contrast MR angiography. J Comput Assist Tomogr. 1988 Mar-Apr;12(2):304–313. doi: 10.1097/00004728-198803000-00021. [DOI] [PubMed] [Google Scholar]
- Zhou Y. Q., Faerestrand S., Matre K., Birkeland S. Velocity distributions in the left ventricular outflow tract and the aortic anulus measured with Doppler colour flow mapping in normal subjects. Eur Heart J. 1993 Sep;14(9):1179–1188. doi: 10.1093/eurheartj/14.9.1179. [DOI] [PubMed] [Google Scholar]


