Valve area and cardiac output in aortic stenosis: Quantification by magnetic resonance velocity mapping

Søndergaard, Lise; Hildebrandt, Per; Lindvig, K; Thomsen, Carsten; Ståhlberg, Freddy; Kassis, Eli; Henriksen, Otto Mølby

doi:10.1016/0002-8703(93)90669-z

Cited by 105 publications

(50 citation statements)

References 26 publications

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“…Early animal studies (6) also showed a good correlation between the flow rates measured with PVM and conventional flow meters. PVM measurements in humans correlated with conventional velocimetric techniques, such as Doppler ultrasound, and with other nonvelocimetric diagnostic techniques (2,(7)(8)(9)(10)(11)(12).…”

Section: Introductionmentioning

confidence: 85%

Evaluation of the Precision of Magnetic Resonance Phase Velocity Mapping for Blood Flow Measurements

Chatzimavroudis

Oshinski

Franch

et al. 2001

Journal of Cardiovascular Magnetic Resonance

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Section: Introductionmentioning

confidence: 85%

Evaluation of the Precision of Magnetic Resonance Phase Velocity Mapping for Blood Flow Measurements

Chatzimavroudis

Oshinski

Franch

et al. 2001

Journal of Cardiovascular Magnetic Resonance

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“…Kilner et al 16 were among the first to show in 2 patients the potential for quantitative assessment of aortic valve stenosis by CMR. Soon thereafter, Sondergaard et al 5,17 used velocityencoded CMR to estimate orifice area (through planimetry of the peak systolic velocity jet) in 12 patients, illustrating good correlation with invasive catheterization. Other investigators also have demonstrated excellent correlations between CMR and invasive hemodynamic data for assessment of instantaneous peak aortic valve velocities and pressure gradients.…”

Section: Discussionmentioning

confidence: 99%

Practical Value of Cardiac Magnetic Resonance Imaging for Clinical Quantification of Aortic Valve Stenosis

et al. 2003

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Background-Valvular pathology can be analyzed quickly and accurately through the use of Doppler ultrasound. For aortic stenosis, the continuity equation approach with Doppler velocity-time integral (VTI) data is by far the most commonly used clinical method of quantification. In view of the emerging popularity of cardiac magnetic resonance (CMR) as a routine clinical imaging tool, the purposes of this study were to define the reliability of velocity-encoded CMR as a routine method for quantifying stenotic aortic valve area, to compare this method with the accepted standard, and to evaluate its reproducibility. Methods and Results-Patients (nϭ24) with aortic stenosis (ranging from 0.5 to 1.8 cm 2 ) were imaged with CMR and echocardiography. Velocity-encoded CMR was used to obtain velocity information in the aorta and left ventricular outflow tract. From this flow data, pressure gradients were estimated by means of the modified Bernoulli equation, and VTIs were calculated to estimate aortic valve orifice dimensions by means of the continuity equation. The correlation coefficients between modalities for pressure gradients were rϭ0.83 for peak and rϭ0.87 for mean. The measurements of VTI correlated well, leading to an overall strong correlation between modalities for the estimation of valve dimension (rϭ0.83, by means of the identified best approach). For 5 patients, the CMR examination was repeated using the best approach. The repeat calculations of valve size correlated well (rϭ0.94). Conclusions-Velocity-encoded CMR can be used as a reliable, user-friendly tool to evaluate stenotic aortic valves.

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“…Velocity information was acquired over one or two heart cycles (acquisition time of 3-7 min). Accuracy and precision of this technique has been thoroughly validated (2,16,26). Figure 2 shows an example of the velocity mapping technique in an image plane perpendicular to the inferior caval vein.…”

Section: Magnetic Resonance Imagingmentioning

confidence: 98%

Total heart volume variation throughout the cardiac cycle in humans

Carlsson

Cain²,

Holmqvist

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

112

126

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heart volume (atria plus ventricles) during a cardiac cycle affect efficiency of cardiac pumping. The goals of this study were to confirm the presence, extent, and contributors of total heart volume variation during the cardiac cycle in healthy volunteers with the use of MRI. Eight healthy volunteers were examined by MRI at rest. Changes in total cardiac volume throughout the cardiac cycle were calculated using the following methods: 1) planimetry derived from gradient-echo cine images and 2) flow-sensitive sequences to quantify flow in all vessels leading to and from the heart. The maximum total heart volume diminished during systole by 8.2 Ϯ 0.8% (SEM, range 4.8 -10.6%) measured by method 1 and 8.8 Ϯ 1.0% (SEM, range 5.6 -11.8%) by method 2 with good agreement between the methods [difference according to Bland-Altman analysis Ϫ0.6% Ϯ 1.0% (SD), intraclass correlation coefficient ϭ 0.999]. This decrease in volume is predominantly explained by variation at the midcardiac level at the widest diameter of the heart with a left-sided predominance. In the short axis of the heart, the change of slice volume was proportional to the end-diastolic slice volume. The present study has confirmed the presence of total heart volume variation that predominantly occurs in the region of atrioventricular plane movement and on the left side. The total heart volume variation may relate to the efficiency of energy use by the heart to minimize displacement of surrounding tissue while accounting for the energy required to draw blood into the atria during ventricular systole. magnetic resonance imaging; left ventricle; output THE CHARACTERISTICS OF HUMAN cardiac function have been studied for centuries (27) with the knowledge acquired providing detailed insights into the fundamental physiology of this organ. Although much of this research has concentrated on the characteristics of the individual cardiac chambers, little is known about total heart volume variation during the cardiac cycle and the respective contributors to this variation. The extent of any volume variation is not just of "academic" concern because it reflects the efficient use of energy by the heart; a large total volume change could result in energy loss through displacement of surrounding tissues or induce a pendular motion of cardiac tissue and blood (11,12,14,20).In 1932, Hamilton and Rompf (11) described a relative constancy of the total heart volume during the cardiac cycle in frogs, turtles, and dogs. They concluded that through the motion of the atrioventricular (AV) plane, the heart was able to pump blood but still maintain the same volume. Subsequent noninvasive investigations in cats (10) and dogs (12,14) were concordant with this initial finding of a relatively consistent cardiac volume. Investigations in humans with the use of computed tomography (15) and MRI in ventilated patients (18) have suggested that a volume variation of 8 -13% may occur between diastole and systole. However, recent work (7) with the use of high-resolution MRI found a lower volume va...

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Valve area and cardiac output in aortic stenosis: Quantification by magnetic resonance velocity mapping

Cited by 105 publications

References 26 publications

Evaluation of the Precision of Magnetic Resonance Phase Velocity Mapping for Blood Flow Measurements

Evaluation of the Precision of Magnetic Resonance Phase Velocity Mapping for Blood Flow Measurements

Practical Value of Cardiac Magnetic Resonance Imaging for Clinical Quantification of Aortic Valve Stenosis

Total heart volume variation throughout the cardiac cycle in humans

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