(Circulation. 1999;99:1611-1617.)
© 1999 American Heart Association, Inc.
Basic Science Reports |
Three-Dimensional Reconstruction of the Color Doppler–Imaged Vena Contracta for Quantifying Aortic Regurgitation
Studies in a Chronic Animal Model
From the Clinical Care Center for Congenital Heart Disease (Y.M., S.W., T.I., X.L., D.J.S.), Oregon Health Sciences University, Portland; The Cleveland Clinic Foundation (T.S.), Cleveland, Ohio; The Laboratory of Animal Medicine and Surgery (M.J.), National Heart, Lung, and Blood Institute, Bethesda, Md; and Noninvasive Cardiac Laboratory (A.D., N.G.P.), Tufts-New England Medical Center, Boston, Mass.
Correspondence to Michael Jones, MD, NIH/National Heart, Lung, and Blood Institute, 9000 Rockville Pike, Bldg 14E, Room 1074A, Bethesda, MD 20892.
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Abstract |
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Background—The purpose of this study was to investigate the use of 3-dimensional (3D) reconstruction of color Doppler flow maps to image and extract the vena contracta cross-sectional area to determine the severity of aortic regurgitation (AR) in an animal model. Evaluation of the vena contracta with 2-dimensional imaging systems may not be sufficiently robust to fully characterize this region, which may be asymmetrically shaped.
Methods and Results—In 6 sheep with surgically induced chronic AR, 18 hemodynamically different states were studied. Instantaneous regurgitant flow rates were obtained by aortic and pulmonary electromagnetic flowmeters (EMFs) as reference standards, and aortic regurgitant effective orifice areas (EOAs) were determined from EMF regurgitant flow rates divided by continuous-wave (CW) Doppler velocities. Composite video data for color Doppler imaging of the aortic regurgitant flows were transferred into a TomTec computer after computer-controlled 180° rotational acquisition. After the 3D data transverse to the flow jet were sectioned, the smallest proximal jet cross section was identified for direct measurement of the vena contracta area. Peak regurgitant flow rates and regurgitant stroke volumes were calculated as the product of these areas and the CW Doppler peak velocities and velocity-time integrals, respectively. There was an excellent correlation between the 3D-derived vena contracta areas and reference EOAs (r=0.99, SEE=0.01 cm2) and between 3D and reference peak regurgitant flow rates and regurgitant stroke volumes (r=0.99, difference=0.11 L/min; r=0.99, difference=1.5 mL/beat, respectively).
Conclusions—3D-based determination of the vena contracta cross-sectional area can provide accurate quantification of the severity of AR.
Key Words: blood flow • regurgitation • echocardiography • imaging
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Introduction |
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Developments in the fluid dynamic concepts governing laminar flow and regurgitation through a restrictive orifice have raised interest in the effective regurgitant orifice area (EOA) as an indicator of the severity of valvular regurgitation.1 2 3 4 5 Previously, the EOA has been calculated by use of the continuity equation and quantitative Doppler methods,1 2 as well as by the proximal flow convergence method.3 4 5 However, these methods may be problematic or cumbersome to apply in the clinical setting.
Quantitative pulsed Doppler methodologies cannot be applied in the presence of combined mitral and aortic regurgitation (AR), and the proximal flow convergence method requires geometric assumptions and the need to select a suitable aliasing velocity range. The EOA corresponds hydrodynamically to the vena contracta cross-sectional area.6 7 8 The vena contracta is located at the smallest region between the proximal laminar flow acceleration zone and the distal turbulent regurgitant jet spray.9 Recent studies have shown that measuring the vena contracta is not only a good predictor of the severity of regurgitation,6 7 10 11 12 13 14 but it can also provide a means of estimating regurgitant flow rates.8 15 The vena contracta method is simple and less technically demanding than other methods and may be less dependent on loading conditions.6 In almost all studies that attempted to quantify the regurgitant flow rates using the 2-dimensional (2D) and color Doppler–imaged vena contracta, the regurgitant flow rate was calculated with the assumption that the configuration of EOA (vena contracta) defined with 2D imaging was symmetrical in 3-dimensional (3D) space.8 15 However, it is well known that regurgitant orifice geometry in patients is often not uniform. For example, slitlike stenotic and regurgitant orifices can occur with bicuspid aortic valves.16 17 Because the shapes of regurgitant orifices can be quite variable, 2D methods for imaging the vena contracta in a direction parallel to flow may not be robust enough to characterize morphologically complex flow zones. Transverse views that can show the vena contracta cross section are at a poor angle to define the jet core. Recent developments in ultrasound and computer technology have made possible the dynamic 3D reconstruction of flow jets from conventional 2D images.18 19 Several studies have demonstrated that such 3D ultrasound methods can accurately depict orifice shapes.20 21 In addition, the direct measurement of the vena contracta cross-sectional area derived by the 3D method does not require the use of geometric assumptions. Because interrogation of regurgitant flow can be performed parallel to flow and the vena contracta cross section extracted from transverse sections of the 3D flow data sets, we propose herein that the 3D method can provide better quantification of the regurgitant flow in vivo than 2D vena contracta methods. The purpose of this study was to investigate the feasibility and value of 3D reconstruction of the vena contracta region for determining the severity of AR in a chronic animal model with strictly quantifiable regurgitation.
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Methods |
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Experimental Preparation
Six juvenile sheep weighing 31 to 51 kg (mean, 46±16 kg) were studied. Six to 15 months (mean, 10±3 months) before the hemodynamic and ultrasonic studies that constitute the experimental setting for this study, the sheep had undergone thoracotomy and cardiopulmonary bypass. These animals were studied and previously reported in an article developing a method for 3D flow convergence imaging in AR.22 During this procedure, the free edge of the right coronary cusp (n=1) or the noncoronary cusp (n=5) of the aortic valve was severed with a radial incision under direct vision. Subsequent aortic dilation and/or leaflet retraction resulted in anatomic leaflet defects and failure of coaptation. All operative and animal management procedures were approved by the Animal Care and Use Committee of the National Heart, Lung, and Blood Institute. Preoperative, intraoperative, and postoperative animal management and husbandry methods are described in detail elsewhere.23 24 During the recovery period, the animals were maintained on digoxin and furosemide. At the time of experimental study when the sheep were returned to the laboratory, anesthesia was induced with intravenous sodium pentobarbital (25 mg/kg body weight) and maintained by use of 1% to 2% isoflurane with oxygen. The sheep were intubated and ventilated with a volume-cycle respirator.
Electromagnetic Flow Probe and Meters
A Swan-Ganz catheter was placed in the main pulmonary
artery through the femoral vein. Another catheter was positioned in the
right femoral artery to monitor systemic arterial pressure
and arterial blood gasses. These catheters were interfaced
with a physiological recorder (ES 2000, Gould
Inc) with fluid-filled pressure transducers (model PD23ID, Gould
Statham). Arterial blood gasses and pH were maintained
within physiological ranges. Bilateral
thoracotomies were performed. Two electromagnetic flow probes (model
EP455, Carolina Medical Electronics, Inc) were placed, 1 around the
skeletonized ascending aorta distal to the coronary ostia and
proximal to the brachiocephalic trunk and the second around the
pulmonary artery just above the pulmonary valve. Both
flow probes were connected to flowmeters (model FM501, Carolina Medical
Electronics) and interfaced to the same
physiological recorder (ES 2000) that was used
for pressure recording. Aortic and left ventricular
pressures were obtained from intracavity manometer-tipped catheters
(model SPC-350, Millar Instruments, Inc) positioned transmurally. All
hemodynamic data were recorded at paper speeds of
250 mm/s. Four consecutive cardiac cycles were analyzed
for each hemodynamic determination.
Calibration factors for the flow probes were corrected for each animal's hematocrit levels, according to the manufacturer's specifications. The problem of the zero baseline drift was managed as follows: The pulmonary artery flow zero-level baseline was adjusted according to the contour of its electromagnetic flow probe signal; this baseline was reconfirmed by occlusive zero. No animal had physiologically important pulmonary regurgitation. Then, the baseline for aortic flow recording was adjusted until the forward minus the backward flow volume equaled the pulmonary forward flow volume. The difference between pulmonary and aortic forward flow represented AR flow volume. This method ignores coronary arterial flow runoff. Coronary arterial blood flow during ventricular diastole was measured in 3 sheep in a preliminary study and was found to be small (0.13 to 0.23 L/min). As in other studies of AR,1 these values were considered negligible compared with the regurgitant volumes delineated in the present study.
Once the curves for pulmonary and aortic flow were properly adjusted, instantaneous regurgitant flow rate could be determined, and aortic regurgitant volume, the integrals of instantaneous retrograde flow rate during diastole, was determined by planimetry of the flow signal recording. Regurgitant fraction was calculated as diastolic reverse aortic flow volume per minute divided by total forward aortic flow volume per minute.
After baseline measurements were obtained, various degrees of severity of AR were produced by altering preload and/or afterload with blood transfusion and angiotensin II (Peptide Institute Inc, provided by Tanabe Seiyaku Co). Calibrations of the flow probes were readjusted before each individual hemodynamic steady state, compensating for any changes in hematocrit produced by insensible fluid loss, blood loss, or the alteration of the preload by blood transfusion. A total of 22 stable hemodynamic states (2 to 5 per sheep) were obtained.
Echocardiography and Data Acquisition
Color Doppler was performed with a 5-MHz annular array
transducer placed directly on the heart near the apex, running on an
ATL-Interspec Apogee RX 400 ultrasound system. The color Doppler
filter was set at 1000 to 1500 Hz. A pulse repetition frequency of 4.0
to 6.0 kHz was used for color Doppler scanning. Gain settings were
optimized for image quality with the maximal color gain level that
would not introduce signals outside areas of flow. Once established,
depth and gain settings were not changed during the recording
period. Aliasing velocities of 0.64 m/s were selected for imaging of
the AR jet, including both the vena contracta and flow convergence
region. In our previous in vitro steady flow studies,25 we
had observed the influences of color Doppler instrument settings on
transfer of the color flow mapping data into a black-and-white video
composite data milieu for 3D reconstruction. We determined that a red
to yellow to blue velocity map and nonvariance color encoding produced
the most clearly defined vena contracta and proximal flow field
flow-convergence imaging.
For 3D-image acquisition, the standard thoracic probe described above was mounted on a holding gantry that positioned the probe on the apex of the heart in a prototype stepper motor system that was controlled by the dedicated 3D-image–processing computer (TomTec Imaging Systems). The stepper motor, which was driven by a steering logic in the TomTec computer, allowed rotation of the probe at any desired increment between 0° and 180° while the probe was scanning the heart. With 1° increments of probe rotation, 180 slices of the region of interest were obtained over the entire scan arc (180°) for each hemodynamic condition and transferred to the TomTec computer as previously reported.18 To ensure exact spatial and temporal resolution, images were gated to the respiratory cycle and R wave on the ECG at heart rates of 64 to 136 bpm but were constant during each steady state. An ECG gating interval of <20% of the RR interval (less than ±40 ms) and respiratory gating within limits between inspiration and the expiratory phase were predetermined before image acquisition by use of the "observe" function of the instrument. When the ECG and respiratory gating met the predetermined limits, video composite image data were acquired at 33-ms intervals (33 frames per second) after the R-wave signal. The frame rate of the 3D-reconstructed images was not limited by the TomTec system or 3D method, but in reality, it was limited to 12 to 17 frames/s by the original color Doppler acquisition frame rates. Image acquisition took a mean of 112±56 seconds to accomplish. Once the scanning sequence was completed, the digital images were stored for postprocessing.
3D Reconstruction, Vena Contracta Area, and Estimation of the
Severity of AR
Manipulation of the data set was performed offline as described
previously.26 After image alignment, a process of
interpolation allowed the TomTec computer to fill in the gaps between
slices to obtain the reconstruction of AR jet and flow convergence. The
final image was displayed in a dynamic mode or in a static mode
reviewed frame by frame and viewed in different projections. From
dynamic 3D data sets, we determined the vena contracta by cutting the
jet zone from distal to proximal perpendicular to its origin in the
aortic leaflet plane using the software of the TomTec computer. This
position corresponded to the junction of the smallest cross section
between the flow convergence zone and regurgitant jet spray (Figure 1
). This point could always be observed
consistently through the cardiac cycle but was sometimes
clearly defined in only 2 or 3 frames because the aortic valve leaflets
and the AR jet both moved during diastole. The timing of
measuring the cross-sectional area of the vena contracta was selected
with use of the ECG as well as the flow image on the monitor screen of
the TomTec system. The cross-sectional area of the vena contracta in
early diastole was chosen in the parallel plane
analysis window for review of the 3D data sets. The vena
contracta cross-sectional area was then measured by use of the computer
trackball.
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Calculation of Regurgitant Flow
Guided by 2D and color Doppler imaging of the regurgitant
jet and valve, continuous-wave (CW) Doppler recordings of
the regurgitant flow velocity parallel to the direction of the aortic
regurgitant jet were performed. The velocity-time integral (VTI) was
determined by planimetry of the area under the spectral Doppler
velocity curve, and peak velocity of AR flow was also obtained. At
least 3 measurements of each variable were averaged. Peak
regurgitant flow rate was calculated as the product of the
cross-sectional area of the vena contracta and the peak velocity of AR
flow by CW Doppler (peak regurgitant flow rate=vena contracta
areaxpeak velocity of AR flow). Regurgitant stroke volume/beat was
also calculated as the product of the cross-sectional area of the
vena contracta and the diastolic VTI (regurgitant stroke
volume/beat=vena contracta areaxVTI).8 15
We calculated the electromagnetic flowmeter (EMF)–derived reference maximal EOA by dividing the peak flow rate by the corresponding CW Doppler peak velocity of AR flow on the same beat (reference maximal EOA=peak flow rate obtained by EMF/peak velocity of AR flow by CW Doppler).
Interobserver Variability
To evaluate the effect of observer variability on the
measurement of the cross-sectional areas of the vena contracta and the
regurgitant volumes/beat calculated from the vena contracta areas, 10
randomly selected flow conditions were analyzed at different
times with the same computer by 2 independent observers (Y.M. and
S.W.), each without knowledge of the results obtained by the other or
the actual flow data.
Statistical Analysis
Data are presented as mean±SD. Because multiple points
were used in the same sheep, multivariate linear
regression analysis was used to obtain correlation coefficients
between the reference electromagnetic flow data and the values measured
or calculated by the 3D method. The cross-sectional areas of the vena
contracta by the 3D method were also compared with the reference peak
flow rates, the reference regurgitant volumes/beat, and the reference
regurgitant fractions by multivariate linear regression
analysis. To do this, we created the data matrix in the
spreadsheet of a statistical computer program (StatView 4.0, Abacus
Concepts Inc) using dummy variables as columns to encode the
different sheep and used the multiple regression function of
StatView.27 Agreement with 2 measurements was tested
according to the method of Bland and Altman.28 A
P value of <0.05 was considered statistically
significant.
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Results |
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For all but 4 of the 22 hemodynamic conditions, video composite data of color Doppler flow mapping images transferred into the TomTec computer yielded satisfactory images of the vena contracta region. Therefore, the study data include 18 hemodynamic steady states. The average time for reconstruction was 15 minutes.
Severity of AR
Aortic regurgitant stroke volumes/beat and regurgitant fractions
for the 18 hemodynamic conditions were within
clinically relevant ranges of mild to moderate AR: from 1.0 to 23
mL/beat (mean, 12.5±8.6 mL/beat) and from 3% to 42% for regurgitant
fraction (mean, 26±13%), respectively. Peak regurgitant flow rates
varied from 1.2 to 8.4 L/min (mean, 3.2±1.8 L/min).
3D Echocardiography and Maximal EOA Determined
by Electromagnetic Flows
The shape of the vena contracta reconstructed by the 3D
method was most often not symmetrical (Figure 1
, right). The
maximal regurgitant EOAs derived by the EMF varied from 0.05 to 0.27
cm2 (mean, 0.12±0.07 cm2).
The vena contracta cross-sectional areas measured by the 3D method
varied from 0.05 to 0.27 cm2 (mean, 0.13±0.06
cm2). The cross-sectional areas of the vena
contracta measured by the 3D method agreed well with the maximal EOAs
derived by the EMF (r=0.99, SEE=0.01
cm2, P<0.0001,
difference=0.004±0.012 cm2) (Figure 2).
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Relationship of the Vena Contracta Area by 3D Method to the
Severity of AR
The results of multivariate linear regression
analysis between the 3D-measured vena contracta areas and
electromagnetically obtained peak regurgitant flow rates, regurgitant
stroke volumes/beat, and regurgitant fractions are listed in the Table.
The 3D-measured vena contracta
areas correlated well with volumetric measurements of the severity of
AR (peak regurgitant flow rates: r=0.99, SEE=0.01
cm2, P<0.0001; regurgitant stroke
volumes/beat: r=0.97, SEE=0.02 cm2,
P<0.0001; and regurgitant fractions: r=0.94,
SEE=0.03 cm2, P<0.0001).
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Use of 3D Vena Contracta With CW Doppler for Estimation of
Severity of AR
Excellent correlations and agreements between peak
regurgitant flow rates determined by the 3D method combined with CW
Doppler and those by the EMF were demonstrated (r=0.99,
SEE=0.32 L/min, difference=0.11±0.30 L/min) (Figure 3). There was also good correlation
between the regurgitant stroke volumes/beat determined by the EMF and
those calculated by the 3D method (r=0.99, SEE=1.46 mL/beat,
P<0.0001, difference=1.6±2.2 mL/beat) (Figure 4).
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Interobserver Variability
There was good agreement between the 2 independent observers'
measurements for 3D-measured vena contracta areas (r=0.91,
mean difference=0.01±0.01 cm2,
P=0.0003) and regurgitant stroke volumes/beat
(r=0.97, mean difference=1.9±1.3 mL/beat,
P<0.0001).
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Discussion |
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In the present study, using strictly quantifiable AR in a chronic animal model, the measurement of the vena contracta area from 3D reconstruction of color flow maps was proven to reliably predict peak EOAs and aortic regurgitant flow volumes. In addition, this method did not require any assumptions about regurgitant orifice size and shape.
Previous 2D and Color Doppler–Imaged Vena Contracta
Studies
Previous in vitro and in vivo
studies6 15 29 30 31 have proposed the use of proximal AR
jet width to estimate the severity of AR. In the in vitro study by
Switzer et al,6 the proximal jet width was the only
reliable independent predictor of both orifice size and regurgitant
fraction, whereas the morphology of AR (such as the jet length and
maximal width of jet) was profoundly dependent on loading conditions.
Several groups, including Perry et al,29 Dolan et
al,30 and Tani et al,31 have shown that the
width of the regurgitant jet at its origin relative to the width of the
left ventricular outflow tract is a better predictor of
severity of AR than is the area of the regurgitant jet or the depth to
which the jet extends into the left ventricle. In these previous
studies,15 29 30 31 how this jet width measurement should be
made was not clearly defined, and the term "vena contracta" was not
used. This is probably because knowledge about flow convergence and
flow dynamics concepts as manifested in color Doppler flow maps was
incomplete at that time. The concept of the vena contracta is now
established in hydrodynamic physics.9 Grayburn et
al11 and Mele et al12 have also extended the
use of this method to mitral regurgitation. Our
previous study13 was the first to describe the location of
the color Doppler vena contracta as the smallest connection between
the laminar flow convergence region and the distal turbulent jet spray
and the first to define its use for more quantitative evaluation of
valvular disease. The cross-sectional area of the vena
contracta corresponds to the regurgitant EOA, which is always smaller
than the anatomic one because of contraction of the flow stream as
blood passes through the restrictive orifice. Because the flow velocity
at the vena contracta (the EOA) is highest along the regurgitant flow
profile, multiplying the vena contracta area by the time integral of CW
Doppler velocity through the regurgitant orifice stream can provide
regurgitant flow volumes. Holm et al15 suggested that
regurgitant flow volume calculated by use of the width of the proximal
jet combined with the time integral of CW Doppler velocity for AR
correlated with angiographic grading. More recently, we8
showed that the color Doppler–imaged vena contracta area
corresponded closely to the reference EOA obtained by EMF and
demonstrated good correlation and agreement between vena
contracta–derived peak flow rates, regurgitant flow volumes per beat
and reference values measured by EMF, a method that is more accurate
than angiography as a reference standard.32 33 However,
the applicability of this method for determination of regurgitant
volume obtained by the 2D-measured width of vena contracta and CW
Doppler velocity requires the assumption that the shape of
regurgitant orifice is relatively uniform in all dimensions and that a
single dimensional measurement (width) can accurately represent
all dimensions. Although some morphological alterations of the aortic
valve may conform to this assumption, the majority of pathological
changes producing more complex shapes will not; eg, the shape of the
regurgitant orifice of a bicuspid valve is commonly
slitlike.16 In our surgical model, the
regurgitation occurred through a resected area that was
triangular but with an outer arc-shaped limb. This is reflected in
Figure 1, right. Taylor et al17 reported that
aortic valve morphology significantly affects regurgitant jet width and
shape in their in vitro study. Theoretically, to define the vena
contracta cross section, one could attempt to obtain a 2D image in a
plane orthogonal to jet propagation, but in this case, the angle would
lead to color flow dropout and distortion. Also, imaging the vena
contracta zone in a single plane parallel to the direction of flow, as
was widely practiced in the reported studies, necessitates an
assumption of a circular and/or symmetrical shape that may not hold
true in clinical practice.
Advantages of This Study
In contrast to the 2D method, the method we propose does not
require any geometric assumptions when the 3D computed flow image is
used as a substrate for measurement. We21 and other
investigators20 have demonstrated that the shape of the
3D-reconstructed vena contracta corresponds well with orifice shape in
vitro in studies in which differently shaped orifices were mounted in a
pulsatile flow model. The geometry of the vena contracta identified by
3D reconstruction was quite difficult to appreciate during 2D imaging.
Because the regurgitant volumes in AR are calculated as the product
of EOAs and peak regurgitant velocities or VTIs, accurate measurements
of EOAs are of primary importance for the correct estimation of
regurgitant volume. Vena contracta areas derived by the 3D method
should be less prone to error when used to determine EOA than those
obtained by 2D methods. In fact, direct measurements of cross-sectional
area of the vena contracta derived by the 3D method seemed to be more
accurate as a measure of EOA than those estimates obtained by 2D color
Doppler imaging. In our previous study using 2D
imaging,8 the simple regression formula between vena
contracta areas obtained from the 2D method and reference EOAs obtained
by EMF was as follows: y=1.2x-0.004,
r=0.91, SEE=0.07 cm2. The simple
regression equation in the present study was
y=0.82x+0.03, r=0.99, SEE=0.01
cm2. Although the study sheep were different,
there seemed to be better correlation of results for this 3D method
than for those in the previous 2D method, because the slope of the
regression with the 3D method was closer to a slope of 1. Moreover, the
SE was smaller with the 3D method. Thus, measurement of the
cross-sectional area of the vena contracta from a 3D reconstruction
could be a useful and potentially accurate method for the study of AR
in clinical patients who have regurgitant valvular orifices
with complicated geometry.
Study Limitations
In this animal study, we used epicardial
echocardiography to select the best transducer
position to obtain good alignment for CW Doppler interrogation of
the vena contracta and aortic regurgitant jet. It has been reported
that the right parasternal view in the right lateral decubitus position
can provide good color Doppler–imaged vena contracta in 78% of
adult patients with AR.34 However, the quality of our
original 2D color Doppler imaging may have been better than that
obtained in the clinical setting. In addition, because the 3D data sets
were derived from 2D imaging during the probe rotation, heart motion
artifacts during acquisition may have degraded the subsequent 3D
images. Another limitation in our method as used in the present
study was that the color Doppler regurgitant flow images obtained
parallel to flow imaged the vena contracta as a function of the
lateral resolution of the scanner, and images were transferred into the
TomTec 3D computer as video composite gray-scale images. Thus, the flow
convergence region and regurgitant flow jet including the vena
contracta were depicted as black-and-white images with various gray
scales in the TomTec system, and there may be a loss of resolution in
the image acquisition and reconstruction method. This might cause
difficulty with adequate differentiation of the vena contracta or
regurgitant flow jet from tissue in the region of valves. Despite these
limitations, the contour of vena contracta could be visualized
satisfactorily and analyzed quantitatively in our study. Our
more recent work with digital 3D Doppler flow maps demonstrated the
feasibility of identifying the vena contracta cross section in 3D data
as a zone of the smallest cross section, a uniform spatial velocity
profile, and the highest mean velocity.35 In the future,
continuing development of computer technology and advanced
parallel-processing ultrasound equipment should provide direct
real-time acquisition and transfer of color-encoded signals in digital
format as velocity assignments into computers capable of displaying 3D
quantitative color Doppler flow images on a beat-to-beat basis.
Conclusions
Our in vivo experimental study indicates that 3D
echocardiographic extraction and measurement of the
vena contracta from color Doppler images may aid quantification of
the severity of AR.
Received July 14, 1998; revision received October 28, 1998; accepted November 18, 1998.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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1. Reimold SC, Ganz P, Bittle JA, Thomas JD, Thoreau D, Plappert TJ, Lee RT. Effective aortic regurgitant orifice area: description of a method based on the conservation of mass. J Am Coll Cardiol. 1991;18:761–768.[Abstract]
2. Reimold SC, Byrne JG, Caguioa ES, Lee CC, Laurence RG, Peigh PS, Cohn LH, Lee RT. Load dependence of the effective regurgitant orifice area in a sheep model of aortic regurgitation. J Am Coll Cardiol. 1991;18:1085–1090.[Abstract]
3.
Vandervoort AE, Levine RA, Thomas JD. Application
of color Doppler flow mapping to calculate effective regurgitant
orifice area: an in vitro study and initial clinical observations.
Circulation. 1993;88:1150–1156.
4. Enriquez-Sarano M, Seward JB, Bailey KR, Tajik AJ. Effective regurgitant orifice area: a noninvasive Doppler development of an old hemodynamic concept. J Am Coll Cardiol. 1994;23:443–451.[Abstract]
5.
Shiota T, Jones M, Yamada I, Heinrich RS, Ishii M,
Sinclair B, Holcomb S, Yoganathan AP, Sahn DJ. Effective regurgitant
orifice area by the color Doppler flow convergence method for
evaluation of the severity of chronic aortic
regurgitation: an animal study. Circulation. 1996;93:594–602.
6.
Switzer DF, Yoganathan AP, Nanda NC, Woo Y-R, Ridgway
AJ. Calibration of color Doppler flow mapping during extreme
hemodynamic conditions in vitro: a foundation for a
reliable quantitative grading system for aortic incompetence.
Circulation. 1987;75:837–846.
7.
Hall SA, Brickner ME, Willet DWL, Irani WN, Afridi I,
Grayburn PA. Assessment of mitral regurgitation
severity by Doppler color flow mapping of the vena contracta.
Circulation. 1997;95:636–642.
8.
Ishii M, Jones M, Shiota T, Yamada I, Heinrich RS,
Holcomb SR, Yoganathan AP, Sahn DJ. Quantifying aortic
regurgitation by using the color Doppler-imaged
vena contracta: a chronic animal model study. Circulation. 1997;96:2009–2015.
9. Yoganathan AP, Cape EG, Sung HW, Williams FP, Jimoh A. Review of hydrodynamic principles for the cardiologist: applications to the study of blood flow and jets by imaging techniques. J Am Coll Cardiol. 1988;12:1344–1353.[Abstract]
10. Fehske W, Omran H, Manz M, Köhler J, Hagendorff A, Lüderitz B. Color-coded Doppler imaging of the vena contracta as a basis for quantification of pure mitral regurgitation. Am J Cardiol. 1994;73:268–274.[Medline] [Order article via Infotrieve]
11. Grayburn PA, Fehske W, Omran H, Brickner ME, Lüderitz B. Multiplane transesophageal echocardiographic assessment of mitral regurgitation by Doppler color flow mapping of the vena contracta. Am J Cardiol. 1994;73:912–917.
12.
Mele D, Vandervoort P, Palacios I, Rivera JM,
Dinsmore RE, Schwammenthal E, Marshall JE, Weyman AE, Levine
RA. Proximal jet size by Doppler flow mapping predicts severity of
mitral regurgitation: clinical study.
Circulation. 1995;91:746–754.
13. Ishii M, Jones M, Shiota T, Heinrich R, Yamada I, Sinclair B, Yoganathan AP, Sahn DJ. Evaluation of eccentric aortic regurgitation by color Doppler jet and color Doppler-imaged vena contracta measurements: an animal study of quantified aortic regurgitation. Am Heart J. 1996;132:796–804.[Medline] [Order article via Infotrieve]
14. Zhou X, Jones M, Shiota T, Yamada I, Teien D, Sahn DJ. Vena contracta imaged by Doppler color flow mapping predicts the severity of eccentric mitral regurgitation better than color jet area: a chronic animal study. J Am Coll Cardiol. 1997;30:1393–1398.[Abstract]
15. Holm S, Eriksson P, Karp K, Osterman G, Teien D. Quantitative assessment of aortic regurgitation by combined two-dimensional, continuous-wave and colour flow Doppler measurements. J Intern Med. 1992;231:115–121.[Medline] [Order article via Infotrieve]
16. Roberts WC. The congenital bicuspid valve: a study of 85 autopsy cases. Am J Cardiol. 1970;26:72–83.[Medline] [Order article via Infotrieve]
17. Taylor AL, Eichhorn EJ, Brickner ME, Eberhart RC, Grayburn PA. Aortic valve morphology: an important in vitro determinant of proximal regurgitant jet width by Doppler color flow mapping. J Am Coll Cardiol. 1990;16:405–412.[Abstract]
18. Belohlavek M, Foley DA, Gerber TC, Greenleaf JF, Seward JB. Three-dimensional reconstruction of color jets in human heart. J Soc Echocardiogr. 1994;7:553–560.
19. Delabays A, Sugeng L, Pandian NG, Hsu TL, Ho SJ, Chen CH, Marx G, Schwartz SL, Cao QL. Dynamic three-dimensional echocardiographic assessment of intracardiac blood flow jets. Am J Cardiol. 1995;76:1053–1058.[Medline] [Order article via Infotrieve]
20. Shandas R, Kwon J, Knudson O, Valdes-Cruz L. Utility of three-dimensional ultrasound Doppler flow reconstruction of the proximal jet flow to quantify regurgitant orifice area: an in-vitro pulsatile flow study. Circulation. 1995;92(suppl I):I-97. Abstract.
21. Delabays A, Shiota T, Teien D, Ge S, Sahn DJ, Pandian NG. Three-dimensional echocardiography allows accurate quantitation of the vena contracta and mitral regurgitation flow rates for asymmetric orifices: an in vitro validation study. Circulation. 1995;92(suppl I):I-798. Abstract.
22.
Shiota T, Jones M, Delabays A, Li X, Yamada I, Ishii M,
Acar P, Holcomb S, Pandian NG, Sahn, DJ. Direct measurement of
three-dimensionally reconstructed flow convergence surface area and
regurgitant flow in aortic regurgitation: in vitro and
chronic animal model studies. Circulation. 1997;96:3687–3695.
23. Jones M, Barnhart GR, Chavez AM, Jett GK, Rose DM, Ishihara T, Ferrans VJ. Experimental evaluation of bioprosthetic valves implanted in sheep. In: Cohn LM, Gallicci V, eds. Cardiac Bioprostheses. New York, NY: York Medical Books; 1982:275–292.
24.
Tamura K, Jones M, Yamada I, Ferrans VJ. A comparison
of failure modes of glutaraldehyde-treated versus
antibiotic-preserved mitral valve allografts implanted in sheep.
J Thorac Cardiovasc Surg. 1995;110:224–238.
25. Shiota T, Sinclair B, Ishii M, Zhou X, Ge S, Teien DE, Gharib M, Sahn DJ. Three-dimensional reconstruction of color Doppler flow convergence region and regurgitant jets: an in vitro quantitative study. J Am Coll Cardiol. 1996;27:1511–1518.[Abstract]
26. Pandian NG, Nanda N, Schwarz S, Fan P, Cao QL, Sanyal R, Hsu TL, Mumm B, Wollschlager H, Weintraub A. Three-dimensional and 4-dimensional transesophageal echocardiographic imaging of heart and aorta in humans using a computed tomographic imaging probe. Echocardiography. 1992;9:677–687.[Medline] [Order article via Infotrieve]
27. Glantz SA, Slinker BK. Primer of Applied Regression and Analysis of Variance: Repeated Measures. New York, NY: McGraw-Hill; 1990:381–463.
28. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1:307–310.[Medline] [Order article via Infotrieve]
29. Perry GJ, Helmcke F, Nanada NC, Byard C, Soto B. Evaluation of aortic insufficiency by Doppler color flow mapping. J Am Coll Cardiol. 1987;9:952–959.[Abstract]
30. Dolan MS, Castello R, Vrain JA, St. Aguirre F, Labovitz AJ. Quantitation of aortic regurgitation by Doppler echocardiography: a practical approach. Am Heart J. 1995;129:1014–1020.[Medline] [Order article via Infotrieve]
31. Tani LY, Minich LL, Day RW, Orsmond GS, Shaddy RE. Doppler evaluation of aortic regurgitation in children. Am J Cardiol. 1997;80:927–931.[Medline] [Order article via Infotrieve]
32. Mennel RG, Joyner CR, Thompson PD, Pyle RR, Macvaugh H. The preoperative and operative assessment of aortic regurgitation: cineaortography vs. electromagnetic flowmeter. Am J Cardiol. 1972;29:360–366.[Medline] [Order article via Infotrieve]
33. Croft CH, Lipscomb K, Mathis K, Firth BG, Nicod P, Tilton G, Winniford MD, Hillis LD. Limitations of qualitative angiographic grading in aortic or mitral regurgitation. Am J Cardiol. 1984;53:1593–1598.[Medline] [Order article via Infotrieve]
34. McDonald RW, Marcella CP. A new window for imaging flow convergence and vena contracta region of aortic regurgitation flows by color Doppler echocardiography: a clinical study. Circulation. 1997;96(suppl I):I-750. Abstract.
35. Li XN, Shiota T, Martin RW, Sahn DJ, Schwartz GA, Park Y, Munt B, Detmer PR, Sheehan FH, Otto CM. Digital three-dimensional Doppler flow mapping: a new modality in echocardiography. Circulation. 1997;96(suppl I):I-329. Abstract.
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