Multiple Unerupted Permanent Teeth Associated with Noonan Syndrome.

The present report describes a case of Noonan's syndrome from a dental viewpoint. Noonan syndrome is an autosomal dominant multisystem disorder. Congenital heart deformities, short stature, thoracic deformities, short neck with webbing, hypertelorism, and malocclusions are some of the frequently observed clinical features. Atypical dental anomalies such as multiple unerupted permanent teeth, multiple submerged and retained deciduous teeth, and supernumerary teeth were found in the present case. Oral prophylaxis and preventive resin restorations were done following which the supernumerary teeth were extracted. 54, 55, 64, 65, 74, 75 and 84 were extracted after orthodontic consultation to facilitate the eruption of permanent teeth. The patient is undergoing fixed orthodontic therapy for forced eruption of unerupted permanent teeth. General dentists should correlate dental anomalies with other systemic features in the diagnosis of such syndromes because of the variability in presentation and the need for multidisciplinary care.

Differential diagnosis of intracavitary tumors obstructing the right ventricular outflow tract.

Three cases of right ventricular outflow tract obstruction caused by 3 distinct tumors-myxoma, sarcoma, and presumed metastatic tumor-diagnosed by transthoracic and transesophageal echocardiography are presented. The differences among these 3 types of tumors with similar clinical and echocardiographic findings are highlighted, and a review of the pertinent literature is discussed. By applying the approximate frequencies of cardiac tumors categorized by type and site, statistically, an intracavitary right ventricular outflow tract tumor is 70 to 140 times more likely to be malignant than benign; furthermore, if it is a primary cardiac tumor, it is approximately 2 times more likely to be a sarcoma than a myxoma.

Utility of transesophageal echocardiography for the characterization of cardiovascular anomalies associated with Turner's syndrome.

This case illustrates the complementary value of transesophageal echocardiography to routine transthoracic echocardiography in an asymptomatic adult patient with Turner's syndrome. The combined findings of bicuspid aortic valve, severe aortic dilation, coarctation of the aorta, and type A aortic dissection were clearly delineated by transesophageal echocardiography.

Left and right atrial volume by freehand three-dimensional echocardiography: in vivo validation using magnetic resonance imaging.

INTRODUCTION: Measurement of left and right atrial size is important for the management of arrhythmias, valvular and congenital heart disease. We have demonstrated that freehand three-dimensional (3D) echocardiography is more accurate and reproducible than two-dimensional (2D) echocardiography for measurement of left ventricular mass and volume. However, no prior study has validated the accuracy of freehand 3D for the determination of left or right atrial volume. METHODS: End-systolic (maximum) left and right atrial volumes were determined in 21 volunteer patients and normal subjects by one, two, and freehand 3D transthoracic echocardiography and compared to volumes obtained by gradient recalled magnetic resonance imaging. Three-dimensional echocardiographic determination of atrial volume was obtained using an acoustic spatial locator, a line-of-intersection display, and a surface reconstruction algorithm. Two-dimensional echocardiographic atrial volumes were obtained from apical biplane images of the left atrium and an apical single plane image of the right atrium using a summation of disks method. One-dimensional (ID) estimates of left atrial volume were determined by cubing the M-mode ID antero-posterior dimension obtained on the parasternal long axis view. RESULTS: An excellent correlation was Obtained between freedhand 3D echocardiography and magnetic resonce imaging (MRI) for the left atrium (r = 0.90, SEE=9.6 ml) and for the right atrium (r = 0.91, SEE = 8.8 ml) with a small bias (left atrium 5.25 ml, right atrium 12.06 ml) and narrow limits of agreement (left atrium 22.14 ml, right atrium 25.54 ml). Two-dimensional echocardiography correlated less well (left atrium r = 0.87, SEE = 10.23 ml, right atrium r = 0.79, SEE = 19.74 ml), and had a higher bias (left atrium 14.46 ml, right atrium 8.99 ml) and larger limits of agreement (left atrium 24.37 ml, right atrium 41.16 ml). One-dimensional estimates of left atrial volume correlated poorly with magnetic resonance determined left atrial volume (r = 0.80, SEE = 6.61 ml) and had unacceptably high bias (45.09 ml) and limits of agreement (35.52 ml). Interobserver variability was lowest for 3D echocardiography (left atrium 7.2 ml, 11%, right atrium 8.7 ml, 16%). CONCLUSIONS: Freehand 3D echocardiography using the line of intersection display for guidance of image positioning and a polyhedral surface reconstruction algorithm is a valid, accurate, reproducible method for determining left and right atrial volume in humans that is comparable to magnetic resonance imaging and is superior to current ID and 2D echocardiographic techniques.

Freehand three-dimensional echocardiography for determination of left ventricular volume and mass in patients with abnormal ventricles: comparison with magnetic resonance imaging.

OBJECTIVE: The objective of this study was to validate the freehand three-dimensional echocardiographic method in patients with abnormal ventricular geometry compared with two-dimensional echocardiography using magnetic resonance imaging as a standard. BACKGROUND: Two-dimensional echocardiographic methods for estimating left ventricular volume and mass in clinical use today are limited by inaccuracies and variations caused by use of geometric assumptions and errors in image plane positioning. Freehand three-dimensional echocardiography with operator guidance by a "line of intersection" display eliminates these assumptions and errors. This method of volume and mass computation has been validated as highly accurate and reproducible in healthy subjects. METHODS: Left ventricular end-systolic and end-diastolic volumes and myocardial mass were determined by freehand three-dimensional echocardiography, by conventional two-dimensional echocardiography using the apical biplane summation of discs method (volume) and the truncated ellipsoid method (mass), by M-mode echocardiography using the Penn method (mass), and by magnetic resonance imaging in 30 patients selected only for the presence of an abnormal ventricle. Results were compared by means of linear regression and the Bland-Altman method of analysis. RESULTS: There was excellent correlation, low bias, and low variability between three-dimensional echocardiography and magnetic resonance imaging for end-diastolic volume (r = 0.90, standard error of the estimate = 31.8 ml, bias = -28.4 ml), end-systolic volume (r = 0.93, standard error of the estimate = 24.1 ml, bias = -13.1 ml), and mass (r = 0.90, standard error of the estimate = 27.3 gm, bias = -22.6 ml). Two-dimensional echocardiography was less accurate and more variable as follows: end-diastolic volume (r = 0.70, standard error of the estimate = 39.8 ml, bias = -33.5 ml), end-systolic volume (r = 0.78, standard error of the estimate = 31.2 ml, bias = -26.7 ml), and mass (r = 0.80, standard error of the estimate = 37.3 gm, bias = 28.9 ml). M-mode echocardiography mass determination (Penn method) was least accurate and most variable (r = 0.075, standard error of the estimate = 78.3 gm, bias = 78.3 gm). CONCLUSIONS: Freehand three-dimensional echocardiography is a method of high accuracy and low variability for computing left ventricular volume and mass in clinical patients with abnormal ventricles. It is superior to conventional one- and two-dimensional echocardiography. The improvement achieved is attributed to elimination of geometric assumptions and image plane positioning errors and additional sampling of the ventricle.

Freehand three-dimensional echocardiography for measurement of left ventricular mass: in vivo anatomic validation using explanted human hearts.

OBJECTIVES: We sought to validate freehand three-dimensional echocardiography for measuring left ventricular mass and to compare its accuracy and variability with those of conventional echocardiographic methods. BACKGROUND: Accurate measurement of left ventricular mass is clinically important as a predictor of morbidity and mortality. Freehand three-dimensional echocardiography eliminates geometric assumptions used by conventional methods, minimizes image positioning errors using a line of intersection display and increases sampling of the ventricle. Preliminary studies have shown it to have high accuracy and low variability. METHODS: Twenty-eight patients awaiting heart transplantation were examined by conventional and freehand three-dimensional echocardiography. Left ventricular mass was determined by the M-mode ("Penn-cube") method, the two-dimensional truncated ellipsoid method and three-dimensional surface reconstruction. The ventricles of 20 explanted hearts were obtained, trimmed and weighed. Echocardiographic mass by each method was compared with true mass by linear regression. Accuracy, bias and interobserver variability were calculated. RESULTS: For three-dimensional echocardiography, the correlation coefficient, standard error of the estimate, root mean square percent error (accuracy), bias and interobserver variability were 0.992, 11.9 g, 4.8%, -4.9 g and 11.5%, respectively. For the two-dimensional truncated ellipsoid method they were 0.905, 38.5 g, 15.6%, 15.4 g and 23.3%. For the M-mode ("Penn-cube") method they were 0.721, 96.9 g, 53.0%, 109.2 g and 19.5%. CONCLUSIONS: Freehand three-dimensional echocardiography for measurement of left ventricular mass has high accuracy and low variability and is superior to conventional methods in hearts of abnormal size and geometry.

Quantitative three dimensional echocardiography in patients with pulmonary hypertension and compressed left ventricles: comparison with cross sectional echocardiography and magnetic resonance imaging.

OBJECTIVE: To evaluate the accuracy of quantitative three dimensional echocardiography in patients with deformed left ventricles. DESIGN: Three dimensional and cross sectional echocardiographic estimates of left ventricular volume and ejection fraction were prospectively compared to those obtained from magnetic resonance imaging. SETTING: Echocardiography laboratory of a university hospital. PATIENTS: 26 patients (9 months to 42 years, median age 11 years) with pulmonary hypertension and fixed reversal of normal interventricular septal curvature. MAIN OUTCOME MEASURES: Left ventricular end diastolic and end systolic volumes and ejection fraction. RESULTS: Three dimensional echocardiographic comparison to magnetic resonance imaging (MRI) yielded r values of 0.94 and 0.87 with a bias of -6.9 (SD 6.9) ml and -16 (11.2) ml for systolic and diastolic volumes respectively. Inter-observer variability was minimal (8.3% and 7.6% respectively). Cross sectional echocardiography gave correlation coefficients of 0.62 and 0.80 and bias of 3.1 (14.1) ml and 16.3 (18.3) ml for systolic and diastolic volumes respectively. Ejection fraction by three dimensional echocardiography also had closer agreement with MRI (bias = 1.1 (7.7)%) than cross sectional echocardiography (bias = 4.4 (13.9)%). CONCLUSIONS: Three dimensional echocardiography provides reliable estimates of left ventricular volumes and ejection fraction, comparable to magnetic resonance imaging in pulmonary hypertension patients with compressed ventricular geometry. Because it eliminates the need for geometric assumptions it shows closer agreement with magnetic resonance imaging in that setting than cross sectional echocardiography.

Validation of three-dimensional echocardiography for quantifying the extent of dyssynergy in canine acute myocardial infarction: comparison with two-dimensional echocardiography.

OBJECTIVES: This study was designed to compare the accuracy of three- and two-dimensional echocardiography for quantifying the extent of abnormal wall motion in experimental acute myocardial infarction, as correlated with the pathologic determination of infarct size. BACKGROUND: Two-dimensional echocardiographic estimations of the fraction of myocardium showing abnormal wall motion are often used as an index of infarct size even though they rely on image plane positioning and geometric assumptions that may not be valid. Three-dimensional echocardiographic reconstruction of the endocardial surface eliminates the need for these assumptions and may improve echocardiographic estimates of infarct size. METHODS: Coronary ligation was performed in 14 open chest dogs, and echocardiographic imaging of the ventricle was performed 6 h later. Three-dimensional echocardiography used seven or eight spatially registered short-axis images to measure percent of endocardial surface and mass showing abnormal wall motion. Three two-dimensional echocardiographic methods using multiple, nonpatially registered images were evaluated. One method used seven or eight-axis slices and a summation of discs algorithm for computing surface area. The second method used the same images and a conical model for the left ventricle. The third used basal, middle and apical short-axis plus apical four- and two-chamber views comparing summed endocardial lengths showing abnormal wall motion with the total of the endocardial dimensions, expressed as percent. The percent of left ventricular mass and surface area infarcted was determined by staining with triphenyltetrazolium chloride. RESULTS: Three-dimensional echocardiographic measurements of endocardial surface and correlated more closely with infarct mass (r = 0.94, SEE +/- 3.6%) than did the two-dimensional method using the summation of discs algorithm (r = 0.85, SEE +/- 6.6%), he summation of conical sections algorithm (r = 0.82, SEE +/- 5.4%) or the method using summed endocardial lengths (r = 0.79, SEE +/- 7.4%). Limits of agreement analysis comparing mass showing abnormal wall motion with anatomic infarct mass surface area showing abnormal wall motion with anatomic infarct surface area showed the smallest limits for three-dimensional echocardiography. CONCLUSIONS: Three-dimensional echocardiography is a more accurate means of noninvasively estimating myocardial infarct size in this canine model than two-dimensional echocardiography.

Three-dimensional echocardiography compared to two-dimensional echocardiography for measurement of left ventricular mass anatomic validation in an open chest canine model.

A three-dimensional echocardiographic system has been developed that can accurately compute left ventricular mass in vitro. This study was designed to validate the new echocardiographic system for the measurement of left ventricular mass in vivo and to compare the accuracy of three-dimensional echocardiography to the accuracy of conventional two-dimensional echocardiography for measuring left ventricular mass. Echocardiographic imaging was performed 6 h following coronary ligation in 20 open chest dogs, at which time the heart was excised and the left ventricle weighed. Three-dimensional echocardiography used multiple short axis sections and polyhedral surface reconstruction to compute myocardial volume. The two dimensional methods employed the truncated ellipsoid model and the area-length model. Myocardial volume was multiplied by 1.05 g/cc and echocardiographic mass estimates were compared to the true left ventricular weight. Three-dimensional echocardiography provided the best correlation (r = 0.96, upsilon r = 0.88 and r = 0.83 for the truncated-ellipsoid and area-length methods, respectively), and the lowest standard error of the estimate for the regression equation (+/- 5.5 g upsilon +/- 11.0 and +/- 14.6 g, respectively). Three dimensional echocardiography also had the lowest standard deviation for the echo-true mass differences (+/- 5.8 g upsilon +/- 10.7 g and +/- 14.2 g) and a lower root mean square percent error (6.8%) upsilon 12.6% and 12.7%). In this open chest canine model, three-dimensional echocardiography is more accurate than standard two-dimensional echocardiographic methods for measuring left ventricular mass.

Three-dimensional echocardiography: limitations of apical biplane imaging for measurement of left ventricular volume.

A new three-dimensional echocardiographic system creates a "line of intersection" display to allow precise and known positioning of echocardiographic images. Our purpose was to determine whether use of the line-of-intersection display will improve positioning of the apical four-chamber and apical two-chamber views and thereby improve the agreement between estimates of left ventricular volume by apical biplane echocardiography and cineventriculography. Unguided and line of intersection-guided apical biplane views were obtained in 31 patients immediately before cardiac catheterization and single-plane cineventriculography. In 15 patients the line-of-intersection display was used to measure the position of the image plane in studies of unguided and guided methods. Linear regression and limits of agreement analysis were used to assess the agreement between cineventriculographic volumes and echocardiographic volumes determined from each set of images. The Wilcoxon test was used to compare guided and unguided image positioning. The line-of-intersection display improved four-chamber and two-chamber view positioning closer to the center of the ventricle and rotation closer to orthogonal positioning. Guided-image positioning was not able to correct displacement of the ultrasound beam anterior to the ventricular apex without deterioration of image quality in most patients. Despite improvements in image plane positioning, the agreement between echocardiographic and cineventriculographic volumes was unchanged. For end-diastole views, the unguided images had an r value = 0.84, standard error of the estimate of +/- 23.0 cc, and limits of agreement of +/- 62.4 cc. Corresponding values for the guided images at end diastole were r = 0.85, standard error of the estimate of +/- 22.9 cc, and limits of agreement of +/- 60.8 cc. At end systole the unguided results were r = 0.91, standard error of the estimate of 16.8 cc, and limits of agreement of +/- 52.2 cc. The line-of-intersection guiding of image plane positioning can improve apical image positioning but does not improve the agreement between apical biplane echocardiographic and cineventriculographic left ventricular volumes. The optimal apical imaging window is frequently occluded by the rib cage, resulting in a decrease in image quality. This reduction of image quality, combined with assumptions of left ventricular geometry, limit the accuracy of estimates of left ventricular volume from apical biplane echocardiography.

Assessment of cardiac function by three-dimensional echocardiography compared with conventional noninvasive methods.

BACKGROUND: Reliable, serial, noninvasive quantitative estimation of left ventricular ejection fraction is essential for selecting and timing therapeutic interventions in patients with heart disease. Equilibrium radionuclide angiography is widely used for this purpose but has well-recognized limitations. Advantages of echocardiography over equilibrium radionuclide angiography include assessment of wall motion, valvular pathology, and cardiac hemodynamics, in addition to portability, lack of radiation exposure, and substantially lower cost. However, conventional echocardiographic techniques are limited by geometric assumptions, image positioning errors, and use of subjective visual methods. To overcome these limitations, a three-dimensional echocardiographic method was developed. This study compares ejection fraction by three-dimensional echocardiography, quantitative two-dimensional echocardiography, and subjective two-dimensional echocardiographic visual estimation with that by equilibrium radionuclide angiography. METHODS AND RESULTS: Fifty-one unselected patients with suspected heart disease underwent left ventricular ejection fraction determination by equilibrium radionuclide angiography and three-dimensional echocardiography using an interactive line-of-intersection display and a new algorithm, ventricular surface reconstruction, for volume computation. In 44 patients, ejection fractions were also estimated visually by experienced observers from two-dimensional echocardiography and by quantitative two-dimensional echocardiography using an apical biplane summation-of-disks algorithm. An excellent correlation was obtained between three-dimensional echocardiography and equilibrium radionuclide angiography (r = .94 to .97, SEE = 3.64% to 5.35%; limits of agreement, 10.3% to 13.3%) without significant underestimation or overestimation. SEE values and limits of agreement were twofold to threefold lower than corresponding values for all two-dimensional echocardiographic techniques. In addition, interobserver variability was significantly lower for the three-dimensional echocardiographic method (10.2%) than for the apical biplane summation-of-disks method (26.1%) and subjective visual estimation (33.3%). CONCLUSIONS: Determination of ejection fraction by three-dimensional echocardiography yields results comparable to those obtained by equilibrium radionuclide angiography and is substantially superior to all two-dimensional echocardiographic methods. Therefore, three-dimensional echocardiography may be used for accurate serial quantification of left ventricular function as an alternative to equilibrium radionuclide angiography.

Comparison of two- and three-dimensional echocardiography with cineventriculography for measurement of left ventricular volume in patients.

OBJECTIVES: We compared two- and three-dimensional echocardiography with cineventriculography for measurement of left ventricular volume in patients. BACKGROUND: Three-dimensional echocardiography has been shown to be highly accurate and superior to two-dimensional echocardiography in measuring left ventricular volume in vitro. However, there has been little comparison of the two methods in patients. METHODS: Two- and three-dimensional echocardiography were performed in 35 patients (mean age 48 years) 1 to 3 h before left ventricular cineventriculography. Three-dimensional echocardiography used an acoustic spatial locator to register image position. Volume was computed using a polyhedral surface reconstruction algorithm based on multiple nonparallel, unevenly spaced short-axis cross sections. Two-dimensional echocardiography used the apical biplane summation of disks method. Single-plane cineventriculographic volumes were calculated using the summation of disks algorithm. The methods were compared by linear regression and a limits of agreement analysis. For the latter, systematic error was assessed by the mean of the differences (cineventriculography minus echocardiography), and the limits of agreement were defined as +/- 2 SD from the mean difference. RESULTS: Three-dimensional echocardiographic volumes demonstrated excellent correlation (end-diastole r = 0.97; end-systole r = 0.98) with cineventriculography. Standard errors of the estimate were approximately half of those of two-dimensional echocardiography (end-diastole +/- 11.0 ml vs. +/- 21.5 ml; end-systole +/- 10.2 ml vs. +/- 17.0 ml). By limits of agreement analysis the end-diastolic mean differences for two- and three-dimensional echocardiography were 21.1 and 12.9 ml, respectively. The limits of agreement (+/- 2 SD) were +/- 54.0 and +/- 24.8 ml, respectively. For end-systole, comparable improvement was obtained by three-dimensional echocardiography. Results for ejection fraction by the two methods were similar. CONCLUSIONS: Three-dimensional echocardiography correlates highly with cineventriculography for estimation of ventricular volumes in patients and has approximately half the variability of two-dimensional echocardiography for these measurements. On the basis of this study, three-dimensional echocardiography is the preferred echocardiographic technique for measurement of ventricular volume. Three-dimensional echocardiography is equivalent to two-dimensional echocardiography for measuring ejection fraction.

Three-dimensional echocardiography: in vitro and in vivo validation of left ventricular mass and comparison with conventional echocardiographic methods.

OBJECTIVES: This study aimed to validate a method for mass computation in vitro and in vivo and to compare it with conventional methods. BACKGROUND: Conventional echocardiographic methods of determining left ventricular mass are limited by assumptions of ventricular geometry and image plane positioning. To improve accuracy, we developed a three-dimensional echocardiographic method that uses nonparallel, nonintersecting short-axis planes and a polyhedral surface reconstruction algorithm for mass computation. METHODS: Eleven fixed hearts were imaged by three-dimensional echocardiography, and mass was determined in vitro by multiplying the myocardial volume by the density of each heart and comparing it with the true mass. Mass at diastole and systole by three-dimensional echocardiography and magnetic resonance imaging (MRI) was compared in vivo in 15 normal subjects. Ten subjects also underwent imaging by one- and two-dimensional echocardiography, and mass was determined by Penn convention, area-length and truncated ellipsoid algorithms. RESULTS: In vitro results were r = 0.995, SEE 2.91 g, accuracy 3.47%. In vivo interobserver variability for systole and diastole was 16.7% to 27%, 14% to 18.1% and 6.3% to 12.8%, respectively, for one-, two- and three-dimensional echocardiography and was 7.5% for MRI at end-diastole. The latter two agreed closely with regard to diastolic mass (r = 0.895, SEE 11.1 g) and systolic mass (r = 0.926, SEE 9.2 g). These results were significantly better than correlations between MRI and the Penn convention (r = 0.725, SEE 25.6 g for diastole; r = 0.788, SEE 28.7 g for systole), area-length (r = 0.694, SEE 24.2 g for diastole; r = 0.717, SEE 28.2 g for systole) and truncated ellipsoid algorithms (r = 0.687, SEE 21.8 g for diastole; r = 0.710, SEE 24.5 g for systole). CONCLUSIONS: Image plane positioning guidance and elimination of geometric assumptions by three-dimensional echocardiography achieve high accuracy for left ventricular mass determination in vitro. It is associated with higher correlations and lower standard errors than conventional methods in vivo.

Three-dimensional echocardiography. Advances for measurement of ventricular volume and mass.

There is a need for more accurate and reproducible serial measurement of left ventricular volume and mass in individual subjects by echocardiography. Conventional echocardiography has significant measurement variability because of its use of geometric assumptions and image plane positioning errors. Guided three-dimensional echocardiography eliminates geometric assumptions and reduces image plane positioning errors by using a "line of intersection" display. Use of three-dimensional guided imaging for a one-dimensional measurement of the left ventricle resulted in a threefold improvement of interobserver variability over conventional echocardiographic measurements. Computer-aided three-dimensional reconstruction of the ventricle for ventricular volume from a series of 8 to 10 short-axis images also achieved more than a threefold improvement of interobserver variability compared with two-dimensional echocardiography. Three-dimensional echocardiographic computation of ventricular volume and mass in healthy subjects was achieved with an accuracy comparable to magnetic resonance imaging and was superior to two-dimensional echocardiography. Three-dimensional echocardiography promises to be a more accurate method of estimating left ventricular volume and mass and may be suitable for serial study of individual subjects because of its improved accuracy and decreased interobserver variability compared with conventional echocardiographic methods.

Use of transesophageal echocardiography in the detection and consequences of an intracardiac bullet.

A 17-year-old male sustained a gunshot injury to the chest. Transesophageal echocardiography showed the presence of a retained bullet in the pericardium and the absence of an intracardiac shunt, which provided important information for the treatment of the patient.

Three-dimensional echocardiography.

Lack of spatial registration of imaging transducers is a major technical limitation of two-dimensional (2-D) echocardiography. Volume scanning of the heart, or three-dimensional (3-D) echocardiography, is achieved by using a 3-D spatial registration device with a conventional 2-D scanner, or by using a high speed, phased-array real-time scanner. Three-dimensional spatial coordinate systems may be external or internal systems with respect to the scanning transducer. With external systems data acquired from several cardiac windows may be integrated and reconstructed. An external coordinate system allows creation of a "line of intersection" display to guide image positioning in the nonvisualized dimension orthogonal to the real-time image. Use of this display has shown a significant, threefold improvement in the accuracy of image positioning and the reproducibility of chamber measurements. Three-dimensional echocardiography using polyhedral surface reconstruction also yields more accurate measurement of ventricular volume and new measurements of total endocardial surface area and infarct surface area. Computer modeling and 3-D computergraphic displays hold promise of valuable new methods of communication, data analysis, and surgical planning.

Left ventricular volume and endocardial surface area by three-dimensional echocardiography: comparison with two-dimensional echocardiography and nuclear magnetic resonance imaging in normal subjects.

OBJECTIVES: We evaluated a three-dimensional echocardiographic method for ventricular volume and surface area determination that uses polyhedral surface reconstruction. Six to eight nonparallel, unequally spaced, nonintersecting short-axis planes were positioned with a line of intersection display to overcome limitations associated with two-dimensional echocardiography. BACKGROUND: Two-dimensional echocardiographic methods of ventricular volume and surface area determination are limited by assumptions about ventricular shape and image plane position. METHODS: Left ventricular end-diastolic and end-systolic volumes and endocardial surface areas determined by three-dimensional echocardiography and nuclear magnetic resonance (NMR) imaging were compared in 15 normal subjects (7 men, 8 women, aged 23 to 41 years, body surface area 1.38 to 2.17 m2). Ten of these subjects also underwent two-dimensional echocardiography; and end-diastolic and end-systolic volumes were determined by the apical biplane summation of discs method and compared with results of NMR imaging. RESULTS: Interobserver variability was 5% to 8% for three-dimensional echocardiography and 6% to 9% for NMR imaging. Both methods were in close agreement on end-diastolic volume (r = 0.92, SEE = 6.99 ml) and end-systolic volume (r = 0.81, SEE = 4.01 ml) and on end-diastolic surface area (r = 0.84, SEE = 8.25 cm2) and end-systolic surface area (r = 0.84, SEE = 4.89 cm2). Three-dimensional echocardiography and NMR imaging correlated significantly better for end-diastolic volume (r = 0.90, SEE = 7.0 ml) and end-systolic volume (r = 0.88, SEE = 3.1 ml) than did two-dimensional echocardiography and NMR imaging (r = 0.48, SEE = 20.5 ml for end-diastolic volume; r = 0.70, SEE = 5.6 ml for end-systolic volume). CONCLUSIONS: Three-dimensional echocardiography is an in vivo method of measuring left ventricular end-diastolic and end-systolic volumes and endocardial surface area with results comparable to those of NMR imaging. Additionally, three-dimensional echocardiography is superior to the two-dimensional echocardiographic apical biplane summation method because the technique eliminates geometric assumptions and image plane positioning error.

Three-dimensional echocardiography: in vitro validation for quantitative measurement of total and "infarct" surface area.

The rapid development of numerous therapeutic options for myocardial revascularization requires more advanced, quantitative echocardiographic methods such as measurement of total endocardial and infarct surface area to evaluate myocardial infarction and assess the effects of therapy. Two-dimensional echocardiography is insufficiently quantitative for this purpose because it cannot directly measure three-dimensional relationships with such as volume and surface area. To limitation this limitation we have developed a three-dimensional echocardiograph capable of measuring total and regional or "infarct" surface area. In vitro validation of this method has been carried out comparing computed areas with true areas of a pin model and fixed hearts. Infarcts were demarcated on the fixed hearts by placing pins in the myocardium. The pin heads on the epicardial surface defined infarct regions that could be imaged. True surface areas of the pin model were determined by physical measurement and calculation. True areas of the fixed hearts were determined by planimetry of surface casts made with plastic tape. Accuracies for total and infarct areas were 1.36% and 2.13% for the pin model and 1.61% and 3.48% for the fixed hearts. Interobserver variability for both phantoms was less than 2.5%. The standard error of the estimate predicting total and infarct surface area for the fixed hearts was 1.53 cm2 and 0.71 cm2, respectively (p < 0.001). Three-dimensional echocardiography provides a new, accurate method for directly measuring global and regional surface areas and holds promise for improved evaluation of myocardial infarction and assessment of its treatment.