Real-Time Three-Dimensional Echocardiography: A Current View of
What Echocardiography can provide?
*Fadi G. Hage, **Navin C. Nanda
*Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, AL.
**Section of Cardiology, Birmingham Veteran’s Administration Medical Center, Birmingham, AL
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overview of 3DTTE and specific indications in which it has incremental value over 2DTTE and/or 2D transesophageal echocardiography (2DTEE).
HISTORICAL PERSPECTIVE
The advent of 2DTTE revolutionalized noninvasive imaging, but its limitations in clinical practice soon became clear because it only provided images resembling thin slices of cardiac structures. This led to several attempts to develop 3D echocardiography3-8. Morris and Shreve9 introduced a spark gap position-locating approach to provide 3D coordinates but this method could not actually record or view 3D images. Another approach developed by Ghosh et al8 utilized placing the 2D transducer at the cardiac apex and rotating it every few degrees in a sequential manner to obtain multiple slices of the heart which were then reconstructed by computer to obtain 3D images of the left ventricle (LV). The volumes
obtained using this method were validated by angiography.
Raqueno et al10 and Schott et al11 successfully incorporated
velocity information and color Doppler reconstruction in the
apical rotation technique.
The introduction of TEE with its superior image quality
provided further impetus and led to the development of
3DTEE imaging. Using a monoplane TEE probe, transverse
sections at various cardiac levels were obtained by moving
the probe contained in a carriage up and down the esophagus
which were reconstructed to provide 3D images12,13. The
large size of the probe, however, precluded routine clinical
use. Attempts at 3D imaging were made using a regular
biplane TEE probe14. With the probe angulated at 900, it was
rotated in small increments to provide sequential longitudinal
images which were reconstructed in 3D since their spatial
orientation and relationship to each other could be determined.
Subsequently, Nanda et al15 used a multiplane TEE transducer
to create 3D images by keeping the probe stationary at a given
level and rotating it few degrees at a time. This method was
used by several investigators to provide clinically useful
incremental information over 2D imaging and even resulted
in the publication of a book with contributions from many
investigators around the world16. A limitation of this technique
was the acquisition of images over several cardiac cycles
which took some time and produced artifacts due to changes
in heart rate, and patient or probe motion during the procedure.
To obviate this problem, live/RT 3DTTE and subsequently
3DTEE imaging were developed and remain the mainstay of
Correspondence: Navin C. Nanda, University of Alabama at Birmingham, Heart Station SW/S102, 619 19th Street South, Birmingham, AL 35249
Email: nanda@uab.edu
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3D echocardiography as it is currently practiced in the
clinical setting. Initial attempts resulted in the development
of a stand alone system which provided only B-mode images17.
Later, a matrix probe was developed and incorporated into
the regular ultrasound system to provide both B-mode and
color Doppler live/RT 3D images facilitating its use in dayto-
day clinical practice18. Subsequently, the transducer was
made much smaller and incorporated in the TEE probe
providing superior quality 3D images. Initial clinical results
using real time 3DTEE were first published in the year
200719.
EXAMINATION PROTOCOL
In order to generate 3D images, the phased array transducers
utilize a 2D sector, which is similar to the sectors
echocardiographers are accustomed to with 2DTTE, that
travels along the Z-axis which is perpendicular to the sector
plane. Using 3DTTE, the echocardiographer can display the images as a narrow sector (60Úx30Ú) that allows for real time imaging with beat-to-beat variability, or by combining 4 smaller sectors together as a ‘full-volume pyramidal dataset’ (60Úx60Ú). This pyramidal dataset can, in almost all settings, contain the whole area of interest in a single view without the need to move the transducer. The echocardiographer can then dissect the pyramidal dataset using cropping planes for 2D views from any desired angle either in RT or later on in the off-line mode. Since the images obtained more closely resemble actual anatomy than 2DTTE, they are more amenable to manipulation in 3D space in order to derive the needed clinical information. The current accepted protocol for 3DTTE relies heavily on the standard 2DTTE views, familiar to all echocardigraphers, in addition to anatomical orientation to facilitate and standardize the interpretation of the examination (Figure 1)20.
Figure 1. 3DTTE uses cropping planes for anatomical sectioning of the heart therefore allowing for 6 different perspectives for any cardiac structure (A). The cropping can be performed from the left or the right in the sagittal plane (B), from above or below in the coronal plane (C), from the base or the apex in the transverse plane (D), or from non-standard planes that can be used for the best visualization of the structure of interest. Reproduced with permission from Nanda et al. Examination protocol for three dimensional echocardiography. For Adhoc 3D Echo Protocol Working Group Echocardiography 2004;21:763-768. |
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EVALUATION OF VALVULAR DISEASE
Mitral Valve
The mitral valve is a geometrically complex structure; the mitral
annulus has a saddle-like shape, the posterior leaflet consists of
three scallops (P1, P2, and P3 being the anterolateral, middle
and posteromedial scallops respectively), and the anterior leaflet
which can be symmetrically divided into three segments (A1,
A2, and A3 being the anterolateral, middle, and posteromedial
segments)21-23. 3DTTE has gained superiority over its 2D
counterpart in the evaluation of mitral valve pathology since the
latter modality struggles in the visualization of this complex 3D
structure in 2D space.
The assessment of mitral stenosis by 2DTTE is limited by the
indirectness of the pressure half-time method and the difficulty
in assuring that the plane of planimetry is parallel to the valve
orifice at the level of the leaflet tips24-26. 3DTTE has a demonstrable
advantage in this regards, not only due to the ability to orient the
imaging plane in the 3D pyramidal dataset in such a manner as
to be absolutely certain that the planimetered area is that of the
flow-limiting orifice, but also due to its ability to evaluate the
subvalvular apparatus and check for the presence of a thrombus
in the left atrial appendage, therefore avoiding the need for a
TEE27, 28. A direct measurement of the mitral valve area with
3DTTE is therefore a better assessment of mitral stenosis than
2DTTE and can be used even in situations where the 2D
examination is limited such as after balloon valvuloplasty27-31.
An accurate quantitative assessment of mitral regurgitation
severity by 2DTTE can be challenging due to the several
assumptions used in the calculations32-34. By using 3DTTE, the
vena contracta can be captured in a 3D pyramidal dataset and
cropped to the level of the mitral valve leaflet tips in a plane that
is parallel to the orifice. Rotating the image will show the vena contracta en face and allow for measuring its area without the
often invalid assumption of a circular or elliptical shape used in
2DTTE formulas.
This technique provides a load independent assessment of the
regurgitant orifice that compares better than the invasive
angiographic and traditional 2DTTE measurements35.
Since the 3D dataset contains the entire mitral valve apparatus,
a comprehensive evaluation of the leaflet geometry can be done
to assist in surgical planning and in identifying flail leaflets,
chordae rupture and endocarditis as causes of acute mitral
regurgitation36,37. Furthermore, an accurate and precise
identification of the segment or the scallop that is involved in
mitral valve prolapse is possible with 3DTTE and therefore can
help in determining suitability for repair23,31,38,39.
Aortic Valve
The use of 2DTTE with Doppler can lead to underestimation or
overestimation of the severity of aortic stenosis40-42. These errors
are usually compounded in the calculation of the aortic valve
area due to any inaccuracy in measurement of the LV outflow
tract diameter which is squared in the continuity equation. Direct
measurement of the flow-limiting aortic valve orifice is possible
with 2DTTE and 2DTEE but suffers from the same limitations
that are faced with mitral stenosis in aligning the imaging plane
with the orifice43. Using methods similar to the ones described
for mitral stenosis, the aortic valve orifice can be visualized and
measured en face by aligning the imaging plane exactly parallel
to the aortic valve orifice in the short-axis view which can be
quite useful in patients with domed valves and angulated orifices.
These measurements with 3DTTE correlated better with intraoperative
3DTEE reconstruction measurements than with
2DTTE or 2DTEE. Furthermore, it correctly classified surgically
confirmed severe aortic stenosis cases that were missed by
2DTTE44. This incremental value of 3DTTE over 2DTTE has
now been demonstrated by multiple investigators45,46.
Although there are several quantitative methods to gauge the
severity of aortic regurgitation on 2DTTE, the most reliable and
commonly used depends on measuring the width of the vena
contracta. Nevertheless, since only a single dimension of the
vena contracta is seen on the parasternal long axis and apical 5
chamber views it would require often invalid geometric
assumptions to determine the area of the vena contracta. On the
short axis view, the vena contracta can be seen en face but it is
difficult to determine whether the imaging plane is parallel and
at the exact level of the vena contracta47. These serious errors in
measurement can be avoided with the use of 3DTTE as outlined
for mitral regurgitation. Grading the severity of aortic
regurgitation has thus been shown to correlate better with
invasive angiography than 2DTTE48.
Tricuspid and Pulmonary Valves
Unlike mitral stenosis, imaging the tricuspid valve in short axis
to determine the severity of tricuspid stenosis is rarely possible
by 2DTTE but quite feasible with 3DTTE. Also since all 3
leaflets can be seen on 3DTTE, prolapsing segments and flail
leaflets can be easily identified49. Using color Doppler tricuspid
and pulmonary regurgitation can be accurately quantified through
the measurement of the area of the vena contracta34,50.
EVALUATION OF VENTRICULAR
FUNCTION AND THE
CARDIOMYOPATHIES
The most common sought after finding from an echocardiogram
is the Left Ventricular Ejection Fraction (LVEF). Regardless of
its multiple limitations, a quantitative measurement of LVEF
that is accurate and reproducible is invaluable for the management
of cardiac patients. Despite the advent of several other imaging
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| Figure 2. 3DTTE with color Doppler for assessment of vena contracta area. Three-dimensional color Doppler data set showing mitral regurgitation (MR, A) is cropped from top to the level of the vena contracta (arrowhead, B) and tilted to view it en face (C, D). The vena contracta is then planimetered by copying onto a videotape. LA=left atrium; LV=left ventricle. Reproduced with permission from Khanna D et al: Quantification of Mitral Regurgitation by Live Three- Dimensional Transthoracic Echocardiographic Measurements of Vena Contracta Area. Echocardiography 2004;21:737-743. |
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EVALUATION OF CONGENITAL HEART
DISEASE
Although 2DTTE is the most widely adopted imaging modality for the evaluation of congenital heart disease patients, it suffers from the limitation of visualization of complex 3D lesions in 2 dimensions. With the advent of 3DTTE, the echocardiographer is given the opportunity to visualize these lesions in a manner not different than computed tomography or magnetic resonance imaging in a completely non-invasive setting that requires little cooperation from the patients and avoiding the risk of potentially harmful radiation in mostly young individuals. Atrial septal defects, patent foramen ovale and ventricular septal defects are common congenital heart disease lesions that are traditionally imaged with 2DTTE. Recently, percutaneous defect closure has been developed as a viable alternative to surgical correction of these lesions69,70. Although the indications to undergo percutaneous or surgical repair are similar, considerations that are important for the success of a percutaneous approach include the location of the defect, its shape and size and the adequacy of its margins for the placement of such devices69,71,72. Since these defects cannot be visualized ‘en face’ by either 2DTTE or even 2DTEE, the maximum dimension and the geometrical shape can’t be determined with certainty. Therefore, 3DTTE is at a theoretical advantage in the assessment of the size, shape and suitability of these lesions for percutaneous closure73-75. 3DTTE can also be useful for the efficacy of percutaneous closure devices and the detection of post-closure complications such as residual shunts device malposition, embolization and fracture74,76. 3DTTE has also been used for the study of the more complex
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Figure 3. Left atrial ejection fraction (LAEF) as measured by 3DTTE in 12 individual patients with hypertrophic cardiomyopathy before and after alcohol septal ablation (ASA). The LAEF showed a significant improvement from 43.1 ± 9.0% before to 52.5 ± 8.8% after AISA (P=0.001). Reproduced with permission from Hage FG, et al. Effect of alcohol-induced septal ablation on left atrial volume and ejection fraction assessed by real time three-dimensional transthoracic echocardiography in patients with hypertrophic cardiomyopathy. Echocardiography 2008;25(7):784-789 |
ostium primum defects since, unlike 2DTTE, it is able to
evaluate the number and size of all 5 individual leaflets of the
common atrioventricular valve and the atrial septal defect
therefore providing a better subclassification of these defects
than 2DTTE77. Furthemore, since with 3DTTE complex conduit
tracking is possible, it has been used for the visualization of
patent ductus arteriosus, for the selection of patients for
percutaneous correction, and for the diagnosis of complications
from the placement of occluder devices78,79. 3DTTE has also
shown its superiority over 2DTTE for the imaging of multiple
congenital heart disease lesions including coronary anomalies80,81,
Ebstein’s anomaly82, cor triatriatum sinister83, Chiari network84,
and others. EVALUATION OF CARDIAC MASSES 3DTTE has a distinctive advantage over 2DTTE in the assessment of cardiac masses in its ability to visualize the interior of the mass. Since the entire mass can be included in the 3D dataset, cropping of the mass can provide a unique view of its interior composition which can reveal information about its nature85-89. In the case of thrombi, such a look can reveal areas of echolucency in the clot which indicate the beginning of clot lysis62. Since clots start to dissolve from inside to out, this information which is not available on 2D examinations can clearly have therapeutic and prognostic implications (Figure 5). Furthermore, 3DTTE can show the exact point of attachment of the thrombus and define its mobility and therefore estimate its propensity to embolize62. 3DTTE has shown great promise in the evaluation of the left atrial appendage. Historically, 2DTEE has been the method of |
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choice to reliably exclude the presence of a thrombus in the left
atrial appendage. We recently reported our experience with the
use of 2DTTE, 2DTEE and 3DTTE in 92 patients as well as
2DTTE and 3DTTE in another 20 patients who had
contraindications or other considerations that prohibited the use
of 2DTTE86. The left atrial appendage was well visualized with
3DTTE in all patients and was able to identify the thrombus in
all patients diagnosed to have a clot by 2DTEE. Furthermore, in
11 patients who were thought to have a clot by 2DTEE, 3DTTE |
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| Figure 4. The evaluation of ventricular septal defect with 3DTTE. (A,B) The arrowhead shows a defect in the ventricular septum (S). P represents the dehisced patch. C,D: En face view of the defect (arrowhead) without (C) and with (D) color Doppler flow signals. LV=left ventricle; RV=right ventricle. Reproduced with permission from Mehmood F, et al. Usefulness of live/real time three-dimensional transthoracic echocardiography in the characterization of ventricular septal defects in adults. Echocardiography 2006;23(5):421-427. |
revealed the absence of a clot and the presence of a prominent
transversely oriented pectinate muscle. In the 20 patients that
could not have 2DTEE, a clot was seen in 1 patient while the
other 19 underwent cardioversion for atrial fibrillation with no
complication. Therefore, 3DTTE can have a role in evaluating
for the presence of a left atrial appendage in patients not eligible for 2DTEE, as well as to confirm the presence of a mass lesion seen on 2DTEE86. 3DTTE can also be used to examine for the presence of clots in the right atrium and on pacemaker leads and vascular catheters87,88. In the case of cardiac tumors, an inside look at the structure of the mass from within can provide a clue to the diagnosis. For example, fibromas are typically dense, homogeneous masses with central liquefaction while myxomas have localized echoluscent areas consistent with necrosis or hemorrhage89. |
RECENT ADVANCES
Recently, as mentioned previously a TEE probe has been introduced that is capable of RT 3D imaging19. This 3DTEE transducer can provide conventional 2D images but is also capable of live RT 3D imaging. Initial experience with 3DTEE reveals its potential in complementing 2DTTE and 2DTEE especially in guiding surgical interventions on the mitral and aortic valves, the aorta, the LV outflow tract, and in congenital heart disease in addition to the visualization of mass lesions (Figure 8)19,96-99. Another much anticipated advance in the field is the development of 3D speckle tracking which holds the promise to provide a better assessment of LV function, strain, strain rate and dysynchrony than available technologies.
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| Figure 5. The evaluation of a left ventricular (LV) thrombus using 3DTTE. (A) Four-chamber view showing no thrombus or aneurysm in the LV. (B) Anterior-posterior cropping displays the large aneurysmcontaining thrombus (arrow). (C, D) Sectioning of thrombus (C) and viewing it en face (D) shows no evidence of lysis or liquefaction. RV = right ventricle. Reproduced with permission from Duncan K, et al. Incremental value of live/real time threedimensional transthoracic echocardiography in the assessment of left ventricular thrombi. Echocardiography 2006;23(1):68-72. |
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| Figure 6. 3DTTE assessment of a left atrial myxoma. (A) Arrowhead points to a large echolucency consistent with a large hemorrhage. (B) Resected specimen showing a large hemorrhage which corresponds closely to the echolucent area seen on 3DTTE. LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle. Reproduced with permission from Mehmood F, et al. Live three-dimensional transthoracic echocardiographic assessment of left atrial tumors. Echocardiography 2005;22(2):137-143. |
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| Figure 7. 3DTTE assessment of a left atrial hemangioma. (A) Arrowheads point to two of the large number of closely packed echolucencies in the tumor mass with sparse solid tissue. (B) Resected specimen showing multiple vascular areas. LA = left atrium; LV = left ventricle; MV = mitral valve; RA = right atrium; RV = right ventricle. Reproduced with permission from Mehmood F, et al. Live three-dimensional transthoracic echocardiographic assessment of left atrial tumors. Echocardiography 2005;22(2):137-143. |
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In the current era, the advancement of technology has allowed for the development of RT 3DTTE with proven incremental value on top of 2DTTE, and in some cases 2DTEE, for multiple indications which will continue to grow as more experience is gained through ongoing studies. This relatively new imaging modality has all the credentials to revolutionize the use of echocardiography once again.
REFERENCES
1. Krishnamoorthy VK, Sengupta PP, Gentile F, Khandheria BK. History of echocardiography and
its future applications in medicine. Critical care medicine. Aug 2007;35(8 Suppl):S309-313.
2. Feigenbaum H. Evolution of echocardiography. Circulation. Apr 1 1996;93(7):1321-1327.
3. Dekker DL, Piziali RL, Dong E, Jr. A system for ultrasonically imaging the human heart in three
dimensions. Computers and biomedical research, an international journal. Dec 1974;7(6):544-
553.
4. Geiser EA, Lupkiewicz SM, Christie LG, et al. A framework for three-dimensional time-varying
reconstruction of the human left ventricle: sources of error and estimation of their magnitude.
Computers and biomedical research, an international journal. Jun 1980;13(3):225-241.
5. King D, Al-Bana S, Larach D. A new three-dimensional random scanner for ultrasonic/computer
graphic imaging of the heart. In: White DN, Barnes R, eds. Ultrasound in Medicine. New York;
1975:363-372.
6. Moritz WE, Pearlman AS, McCabe DH, et al.. An ultrasonic technique for imaging the ventricle
in three dimensions and calculating its volume. IEEE transactions on bio-medical engineering.
Aug 1983;30(8):482-492.
7. Matsumoto M, Matsuo H, Kitabatake A, et al.. Three-dimensional echocardiograms and twodimensional
echocardiographic images at desired planes by a computerized system. Ultrasound
in medicine & biology. 1977;3(2-3):163-178.
8. Ghosh A, Nanda NC, Maurer G. Three-dimensional reconstruction of echo-cardiographic
images using the rotation method. Ultrasound in medicine & biology. 1982;8(6):655-661.
9. Moritz WE, Shreve PL. A microprocessor based spatial locating system for use with diagnostic
ultrasound. Proc IEEE. 1976;64:966-974.
10. Raqueno R, Ghosh A, Nanda NC. Four-dimensional reconstruction of two-dimensional
echocardiographic images. Echocardiography (Mount Kisco, N.Y.) 1989;6:323-337.
11. Schott JR, Raqueno R, Ghosh A, et al. Four dimensional cardiac blood flow analysis using color
Doppler echocardiography. In: Nanda NC, ed. Textbook of Color Doppler Echocardiography.
Philadelphia: Lea & Febiger; 1989:332-341.
12. Pandian NG, Nanda NC, Schwartz SL, et al. Three-dimensional and four-dimensional
transesophageal echocardiographic imaging of the heart and aorta in humans using a computed
tomographic imaging probe. Echocardiography (Mount Kisco, N.Y. Nov 1992;9(6):677-687.
13. Wollschlager H, Zeiher AM, Klein H, et al. Transesophageal echo computer tomography: A new
method for dynamic 3-D imaging of the heart (Echo-CT). Computers in Cardiology: IEEE
Computer Society; 1990:39.
14. Li ZA, Wang XF, Nanda NC, et al. Three dimensional reconstruction of transesophageal
echocardiographic longitudinal images. Echocardiography (Mount Kisco, N.Y.) 1995;12:367-
375.
15. Nanda NC, Pinheiro L, Sanyal R, et al. Multiplane transesophageal echocardiographic imaging
and three-dimensional reconstruction. Echocardiography (Mount Kisco, N.Y.) 1992;9:667-676.
16. Nanda NC, Sorrell VL. Atlas of Three-Dimensional Echocardiography. Armonk: Futura
Publishing Company 2002.
17. Sheikh K, Smith SW, von Ramm O, Kisslo J. Real-time, three-dimensional echocardiography:
feasibility and initial use. Echocardiography (Mount Kisco, N.Y.) Jan 1991;8(1):119-125.
18. Salgo I, Bianchi M. Gong “live” with 3-D cardiac ultrasound. Today in Cardiology. 2002;5.
19. Pothineni KR, Inamdar V, Miller AP, et al.. Initial experience with live/real time threedimensional
transesophageal echocardiography. Echocardiography (Mount Kisco, N.Y. Nov
2007;24(10):1099-1104.
20. Nanda NC, Kisslo J, Lang R, et al. Examination protocol for three-dimensional echocardiography.
Echocardiography (Mount Kisco, N.Y. Nov 2004;21(8):763-768.
21. Pai RG, Tanimoto M, Jintapakorn W, et al. Volume-rendered three-dimensional dynamic
anatomy of the mitral annulus using a transesophageal echocardiographic technique. The
Journal of heart valve disease. Nov 1995;4(6):623-627.
22. Flachskampf FA, Chandra S, Gaddipatti A, et al. Analysis of shape and motion of the mitral
annulus in subjects with and without cardiomyopathy by echocardiographic 3-dimensional
reconstruction. J Am Soc Echocardiogr. Apr 2000;13(4):277-287.
23. Ahmed S, Nanda NC, Miller AP, et al. Usefulness of transesophageal three-dimensional
echocardiography in the identification of individual segment/scallop prolapse of the mitral valve.
Echocardiography. Feb 2003;20(2):203-209.
24. Karp K, Teien D, Bjerle P, Eriksson P. Reassessment of valve area determinations in mitral
stenosis by the pressure half-time method: impact of left ventricular stiffness and peak diastolic
25. Flachskampf FA, Weyman AE, Gillam L, et al. Aortic regurgitation shortens Doppler pressure
half-time in mitral stenosis: clinical evidence, in vitro simulation and theoretic analysis. JACC.
Aug 1990;16(2):396-404.
26. Wisenbaugh T, Berk M, Essop R, et al. Effect of mitral regurgitation and volume loading on
pressure half-time before and after balloon valvotomy in mitral stenosis. The American journal
of cardiology. Jan 15 1991;67(2):162-168.
27. Singh V, Nanda NC, Agrawal G, et al. Live three-dimensional echocardiographic assessment of
mitral stenosis. Echocardiography. Nov 2003;20(8):743-750.
28. Agoston I, Xie T, Tiller FL, et al. Assessment of left atrial appendage by live three-dimensional
echocardiography: early experience and comparison with transesophageal echocardiography.
Echocardiography. Feb 2006;23(2):127-132.
29. Zamorano J, Cordeiro P, Sugeng L, et al. Real-time three-dimensional echocardiography for
rheumatic mitral valve stenosis evaluation: an accurate and novel approach. Journal of the
American College of Cardiology. Jun 2 2004;43(11):2091-2096.
30. Zamorano J, Perez de Isla L, Sugeng L, et al. Non-invasive assessment of mitral valve area during
percutaneous balloon mitral valvuloplasty: role of real-time 3D echocardiography. Eur Heart
J. Dec 2004;25(23):2086-2091.
31. Sugeng L, Coon P, Weinert L, et al. Use of real-time 3-dimensional transthoracic echocardiography
in the evaluation of mitral valve disease. J Am Soc Echocardiogr. Apr 2006;19(4):413-421.
32. Grossmann G, Giesler M, Stein M, et al. Quantification of mitral and tricuspid regurgitation by
the proximal flow convergence method using two-dimensional colour Doppler and colour
Doppler M-mode: influence of the mechanism of regurgitation. International journal of
cardiology. Oct 30 1998;66(3):299-307.
33. Enriquez-Sarano M, Bailey KR, Seward JB, et al. Quantitative Doppler assessment of valvular
regurgitation. Circulation. Mar 1993;87(3):841-848.
34. Velayudhan DE, Brown TM, Nanda NC, et al. Quantification of tricuspid regurgitation by live
three-dimensional transthoracic echocardiographic measurements of vena contracta area.
Echocardiography. Oct 2006;23(9):793-800.
35. Khanna D, Vengala S, Miller AP, et al. Quantification of mitral regurgitation by live threedimensional
transthoracic echocardiographic measurements of vena contracta area.
Echocardiography. Nov 2004;21(8):737-743.
36. Watanabe N, Ogasawara Y, Yamaura Y, et al. Geometric differences of the mitral valve tenting
between anterior and inferior myocardial infarction with significant ischemic mitral regurgitation:
quantitation by novel software system with transthoracic real-time three-dimensional
echocardiography. J Am Soc Echocardiogr. Jan 2006;19(1):71-75.
37. Watanabe N, Ogasawara Y, Yamaura Y, et al. Quantitation of mitral valve tenting in ischemic
mitral regurgitation by transthoracic real-time three-dimensional echocardiography. Journal of
the American College of Cardiology. Mar 1 2005;45(5):763-769.
38. Patel V, Hsiung MC, Nanda NC, et al. Usefulness of live/real time three-dimensional transthoracic
echocardiography in the identification of individual segment/scallop prolapse of the mitral valve.
Echocardiography. Jul 2006;23(6):513-518.
39. Pepi M, Tamborini G, Maltagliati A, et al. Head-to-head comparison of two- and threedimensional
transthoracic and transesophageal echocardiography in the localization of mitral
valve prolapse. Journal of the American College of Cardiology. Dec 19 2006;48(12):2524-2530.
40. Garcia D, Dumesnil JG, Durand LG, et al. 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. Journal of the
American College of Cardiology. Feb 5 2003;41(3):435-442.
41. Levine RA, Jimoh A, Cape EG, et al. Pressure recovery distal to a stenosis: potential cause of
gradient “overestimation” by Doppler echocardiography. Journal of the American College of
Cardiology. Mar 1 1989;13(3):706-715.
42. Baumgartner H, Stefenelli T, Niederberger J, et al. “Overestimation” of catheter gradients by
Doppler ultrasound in patients with aortic stenosis: a predictable manifestation of pressure
recovery. Journal of the American College of Cardiology. May 1999;33(6):1655-1661.
43. Bernard Y, Meneveau N, Vuillemenot A, Magnin D, et al. Planimetry of aortic valve area using
multiplane transoesophageal echocardiography is not a reliable method for assessing severity
of aortic stenosis. Heart (British Cardiac Society). Jul 1997;78(1):68-73.
44. Vengala S, Nanda NC, Dod HS, et al. Images in geriatric cardiology. Usefulness of live threedimensional
transthoracic echocardiography in aortic valve stenosis evaluation. The American
journal of geriatric cardiology. Sep-Oct 2004;13(5):279-284.
45. Gilon D. Three dimensional echocardiography and aortic valve stenosis. Minerva
cardioangiologica. Dec 2003;51(6):641-645.
46. Goland S, Trento A, Iida K, Czer LS, et al. Assessment of aortic stenosis by three-dimensional
echocardiography: an accurate and novel approach. Heart (British Cardiac Society). Jul
2007;93(7):801-807.
47. Perry GJ, Helmcke F, Nanda NC, et al. Evaluation of aortic insufficiency by Doppler color flow
mapping. Journal of the American College of Cardiology. Apr 1987;9(4):952-959.
48. Fang L, Hsiung MC, Miller AP, et al. Assessment of aortic regurgitation by live three-dimensional
transthoracic echocardiographic measurements of vena contracta area: usefulness and validation.
Echocardiography (Mount Kisco, N.Y. Oct 2005;22(9):775-781.
49. Pothineni KR, Duncan K, Yelamanchili P, et al. Live/real time three-dimensional transthoracic
echocardiographic assessment of tricuspid valve pathology: Incremental value over the twodimensional
technique. Echocardiography. 2007;In Press.
50. Pothineni KR, Wells BJ, Hsiung MC, et al. Live/Real Time Three-Dimensional Transthoracic
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N.Y. 2008;In Press.
51. Jenkins C, Bricknell K, Hanekom L, et al. Reproducibility and accuracy of echocardiographic
measurements of left ventricular parameters using real-time three-dimensional echocardiography.
Journal of the American College of Cardiology. Aug 18 2004;44(4):878-886.
52. Lang RM, Mor-Avi V, Sugeng L, et al. Three-dimensional echocardiography: the benefits of the
additional dimension. Journal of the American College of Cardiology. Nov 21 2006;48(10):2053-
2069.
53. Sugeng L, Mor-Avi V, Weinert L, et al. Quantitative assessment of left ventricular size and
function: side-by-side comparison of real-time three-dimensional echocardiography and computed
tomography with magnetic resonance reference. Circulation. Aug 15 2006;114(7):654-661.
54. Qi X, Cogar B, Hsiung MC, et al. Live/real time three-dimensional transthoracic echocardiographic
assessment of left ventricular volumes, ejection fraction, and mass compared with magnetic
resonance imaging. Echocardiography. Feb 2007;24(2):166-173.
55. Caiani EG, Corsi C, Zamorano J, et al. Improved semiautomated quantification of left ventricular
volumes and ejection fraction using 3-dimensional echocardiography with a full matrix-array
transducer: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. Aug
2005;18(8):779-788.
56. Mor-Avi V, Jenkins C, Kuhl HP, et al. Real-time 3-dimensional echocardiographic quantification
of left ventricular volumes. J Am Coll Cardiol Cardiol Img. 2008;1(4):413-423.
57. Chen G, Sun K, Huang G. In vitro validation of right ventricular volume and mass measurement
by real-time three-dimensional echocardiography. Echocardiography (Mount Kisco, N.Y. May
2006;23(5):395-399.
58. Prakasa KR, Dalal D, Wang J, et al. Feasibility and variability of three dimensional
echocardiography in arrhythmogenic right ventricular dysplasia/cardiomyopathy. The American
journal of cardiology. Mar 1 2006;97(5):703-709.
59. Engberding R, Yelbuz TM, Breithardt G. Isolated noncompaction of the left ventricular
myocardium — a review of the literature two decades after the initial case description. Clin Res
Cardiol. Jul 2007;96(7):481-488.
60. Bodiwala K, Miller AP, Nanda NC, et al. Live three-dimensional transthoracic echocardiographic
assessment of ventricular noncompaction. Echocardiography (Mount Kisco, N.Y. Aug
2005;22(7):611-620.
61. Yelamanchili P, Nanda NC, Patel V, et al. Live/real time three-dimensional echocardiographic
demonstration of left ventricular noncompaction and thrombi. Echocardiography (Mount Kisco,
N.Y. Sep 2006;23(8):704-706.
62. Duncan K, Nanda NC, Foster WA, et al. Incremental value of live/real time three-dimensional
transthoracic echocardiography in the assessment of left ventricular thrombi. Echocardiography
(Mount Kisco, N.Y. Jan 2006;23(1):68-72.
63. Rajdev S, Singh A, Nanda NC, et al. Comparison of two- and three-dimensional transthoracic
echocardiography in the assessment of trabeculations and trabecular mass in left ventricular
noncompaction. Echocardiography (Mount Kisco, N.Y. Aug 2007;24(7):760-767.
64. Caselli S, Pelliccia A, Maron M, et al. Differentiation of hypertrophic cardiomyopathy from other
forms of left ventricular hypertrophy by means of three-dimensional echocardiography. The
American journal of cardiology. Sep 1 2008;102(5):616-620.
65. Bicudo LS, Tsutsui JM, Shiozaki A,et al. Value of real time three-dimensional echocardiography
in patients with hypertrophic cardiomyopathy: comparison with two-dimensional
echocardiography and magnetic resonance imaging. Echocardiography (Mount Kisco, N.Y.
Aug 2008;25(7):717-726.
66. Frans EE, Nanda NC, Patel V, et al. Live three-dimensional transthoracic contrast
echocardiographic assessment of apical hypertrophic cardiomyopathy. Echocardiography
(Mount Kisco, N.Y. Sep 2005;22(8):686-689.
67. Fukuda S, Lever HM, Stewart WJ, et al. Diagnostic value of left ventricular outflow area in
patients with hypertrophic cardiomyopathy: a real-time three-dimensional echocardiographic
study. J Am Soc Echocardiogr. Jul 2008;21(7):789-795.
68. Hage FG, Karakus G, Luke WD, et al. Effect of alcohol-induced septal ablation on left atrial
volume and ejection fraction assessed by real time three-dimensional transthoracic
echocardiography in patients with hypertrophic cardiomyopathy. Echocardiography (Mount
Kisco, N.Y. Aug 2008;25(7):784-789.
69. Moake L, Ramaciotti C. Atrial septal defect treatment options. AACN clinical issues. Apr-Jun
2005;16(2):252-266.
70. Butera G, Chessa M, Carminati M. Percutaneous closure of ventricular septal defects. State of
the art. Journal of cardiovascular medicine (Hagerstown, Md. Jan 2007;8(1):39-45.
71. Chau AK, Leung MP, Yung T, et al. Surgical validation and implications for transcatheter closure
of quantitative echocardiographic evaluation of atrial septal defect. The American journal of
cardiology. May 1 2000;85(9):1124-1130.
72. Pedra CA, Pedra SR, Esteves CA, et al.Percutaneous closure of perimembranous ventricular
septal defects with the Amplatzer device: technical and morphological considerations. Catheter
Cardiovasc Interv. Mar 2004;61(3):403-410.
73. Mehmood F, Vengala S, Nanda NC, et al. Usefulness of live three-dimensional transthoracic
echocardiography in the characterization of atrial septal defects in adults. Echocardiography
(Mount Kisco, N.Y. Nov 2004;21(8):707-713.
74. Sinha A, Nanda NC, Misra V, et al. Live three-dimensional transthoracic echocardiographic
assessment of transcatheter closure of atrial septal defect and patent foramen ovale.
Echocardiography (Mount Kisco, N.Y. Nov 2004;21(8):749-753.
75. Mehmood F, Miller AP, Nanda NC, et al. Usefulness of live/real time three-dimensional
Echocardiography (Mount Kisco, N.Y. May 2006;23(5):421-427.
76. Berdat PA, Chatterjee T, Pfammatter JP, et al. Surgical management of complications after
transcatheter closure of an atrial septal defect or patent foramen ovale. The Journal of thoracic
and cardiovascular surgery. Dec 2000;120(6):1034-1039.
77. Singh A, Romp RL, Nanda NC, et al. Usefulness of live/real time three-dimensional transthoracic
echocardiography in the assessment of atrioventricular septal defects. Echocardiography
(Mount Kisco, N.Y. Aug 2006;23(7):598-608.
78. Sinha A, Nanda NC, Khanna D, et al.Live three-dimensional transthoracic echocardiographic
delineation of patent ductus arteriosus. Echocardiography (Mount Kisco, N.Y. Jul 2004;21(5):443-
448.
79. Hlavacek A, Lucas J, Baker H, et al. Feasibility and utility of three-dimensional color flow
echocardiography of the aortic arch: The “echocardiographic angiogram”. Echocardiography
(Mount Kisco, N.Y. Nov 2006;23(10):860-864.
80. Ilgenli TF, Nanda NC, Sinha A, et al.. Live three-dimensional transthoracic echocardiographic
assessment of anomalous origin of left coronary artery from the pulmonary artery.
Echocardiography (Mount Kisco, N.Y. Aug 2004;21(6):559-562.
81. Mehta D, Nanda NC, Vengala S, et al. Live three-dimensional transthoracic echocardiographic
demonstration of coronary artery to pulmonary artery fistula. The American journal of geriatric
cardiology. Jan-Feb 2005;14(1):42-44.
82. Patel V, Nanda NC, Rajdev S, et al. Live/real time three-dimensional transthoracic
echocardiographic assessment of Ebstein’s anomaly. Echocardiography (Mount Kisco, N.Y.
Nov 2005;22(10):847-854.
83. Patel V, Nanda NC, Arellano I, et al. Cor triatriatum sinister: assessment by live/real time threedimensional
transthoracic echocardiography. Echocardiography (Mount Kisco, N.Y. Oct
2006;23(9):801-802.
84. Pothineni KR, Nanda NC, Burri MV, Set al. Live/real time three-dimensional transthoracic
echocardiographic visualization of Chiari network. Echocardiography (Mount Kisco, N.Y. Oct
2007;24(9):995-997.
85. Asch FM, Bieganski SP, Panza JA, et al. Real-time 3-dimensional echocardiography evaluation
of intracardiac masses. Echocardiography (Mount Kisco, N.Y. Mar 2006;23(3):218-224.
86. Karakus G, kodali V, Inamdar V, et al. Comparative Assessment of Left Atrial Appendage by
Transesophageal and Combined Two and Three-Dimensional Transthoracic Echocardiography.
Echocardiography (Mount Kisco, N.Y. 2008;25.
87. Upendram S, Nanda NC, Mehmood F, et al. Images in geriatric cardiology: live threedimensional
transthoracic echocardiographic assessment of right atrial thrombus. The American
journal of geriatric cardiology. Nov-Dec 2004;13(6):330-331.
88. Upendram S, Nanda NC, Vengala S, et al. Live three-dimensional transthoracic echocardiographic
assessment of thrombus in the innominate veins and superior vena cava utilizing right parasternal
and supraclavicular approaches. Echocardiography (Mount Kisco, N.Y. May 2005;22(5):445-
449.
89. Mehmood F, Nanda NC, Vengala S, et al. Live three-dimensional transthoracic echocardiographic
assessment of left atrial tumors. Echocardiography (Mount Kisco, N.Y. Feb 2005;22(2):137-143.
90. Dod HS, Burri MV, Hooda D, et al. Two- and three-dimensional transthoracic and transesophageal
echocardiographic findings in epithelioid hemangioma involving the mitral valve.
Echocardiography (Mount Kisco, N.Y. Apr 2008;25(4):443-445.
91. Pothineni KR, Nanda NC, Burri MV, et al. Live/real time three-dimensional transthoracic
echocardiographic description of chordoma metastatic to the heart. Echocardiography (Mount
Kisco, N.Y. Apr 2008;25(4):440-442.
92. Suwanjutah T, Singh H, Plaisance BR, et al. Live/real time three-dimensional transthoracic
echocardiographic findings in primary left atrial leiomyosarcoma. Echocardiography (Mount
Kisco, N.Y. Mar 2008;25(3):337-339.
93. Sinha A, Nanda NC, Panwar RB, et al. Live three-dimensional transthoracic echocardiographic
assessment of left ventricular hydatid cyst. Echocardiography (Mount Kisco, N.Y. Nov
2004;21(8):699-705.
94. Muller S, Feuchtner G, Bonatti J, et al. Value of transesophageal 3D echocardiography as an
adjunct to conventional 2D imaging in preoperative evaluation of cardiac masses.
Echocardiography (Mount Kisco, N.Y. Jul 2008;25(6):624-631.
95. Lokhandwala J, Liu Z, Jundi M, et al.Three-dimensional echocardiography of intracardiac
masses. Echocardiography (Mount Kisco, N.Y. Feb 2004;21(2):159-163.
96. Grewal J, Mankad S, Freeman WK, et al. Real-time three-dimensional transesophageal
echocardiography in the intraoperative assessment of mitral valve disease. J Am Soc Echocardiogr.
Jan 2009;22(1):34-41.
97. Sugeng L, Shernan SK, Weinert L, et al. Real-time three-dimensional transesophageal
echocardiography in valve disease: comparison with surgical findings and evaluation of
prosthetic valves. J Am Soc Echocardiogr. Dec 2008;21(12):1347-1354.
98. Baker GH, Shirali G, Ringewald JM, et al. Usefulness of live three-dimensional transesophageal
echocardiography in a congenital heart disease center. The American journal of cardiology. Apr
1 2009;103(7):1025-1028.
99. Scohy TV, Soliman OI, Lecomte PV, et al. Intraoperative real time three-dimensional
transesophageal echocardiographic measurement of hemodynamic, anatomic and functional
changes after aortic valve replacement. Echocardiography (Mount Kisco, N.Y. Jan 2009;26(1):96-
99.
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