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Background: Dobutamine stress echocardiography (DSE) suffers from high interobserver and inter-institution variability in the diagnosis of myocardial ischemia. Therefore, we developed a three-dimensional (3D) analysis tool that makes it possible to anatomically align 3D rest and stress data systematically, to generate optimal, nonforeshortened standard anatomical cross sections and to analyse the images synchronized and side-by-side., Aim of the Study: To investigate whether this 3D analysis tool could improve interobserver agreement on myocardial ischemia during 3D DSE., Methods: The study comprised 34 consecutive patients with stable chest pain who underwent both noncontrast and contrast 3D DSE. Two observers scored segmental wall motion using a conventional analysis and the novel analysis with the new 3D tool., Results: The two observers agreed on the presence or absence of myocardial ischemia in 81 of 102 coronary territories (agreement 79%, kappa (kappa) 0.28) during noncontrast 3D imaging and 92 of 102 coronary territories (agreement 90%, kappa 0.65) during contrast-enhanced 3D imaging. With the new 3D analysis software these numbers improved to 98 of 102 coronary territories (agreement 96%, kappa 0.69) during noncontrast 3D imaging and 98 of 102 coronary territories (agreement 96%, kappa 0.82) during contrast-enhanced 3D imaging., Conclusion: The use of a 3D DSE analysis tool improves interobserver agreement for myocardial ischemia both for noncontrast and contrast images.

Aims: Real-time three-dimensional echocardiography (RT3DE) allows quick volumetric scanning of the left ventricle (LV). We evaluated the diagnostic accuracy of contrast-enhanced stress RT3DE for the detection of coronary artery disease (CAD) in comparison with coronary arteriography as the reference technique., Methods and Results: Forty-five consecutive patients (age 59 +/- 10, 31 males) referred for coronary angiography were examined by contrast-enhanced RT3DE. Wall motion analysis was performed off-line by dedicated software. New or worsening wall motion abnormalities were detected in 17 of 28 patients with significant CAD (sensitivity 61%), and in two of 17 patients without significant CAD (specificity 88%). The sensitivity for detection of single-vessel CAD was 8/15 patients (53%), for two-vessel CAD 4/6 (67%), and for three-vessel CAD 5/7 (71%). In 35 patients, comparison with conventional RT3DE was available. The image quality index at rest improved from 2.5 +/- 1.2 to 3.2 +/- 1.0 (P < 0.001) with contrast and at peak stress from 2.3 +/- 1.2 to 3.1 +/- 1.0 (P < 0.001). Interobserver agreement on the diagnosis of myocardial ischaemia improved from 26 of 35 studies (74%, kappa = 0.44) with conventional stress RT3DE to 30 of 35 studies (86%, kappa = 0.69) with contrast-enhanced stress RT3DE. Sensitivity increased from 50 to 55% and specificity from 69 to 85% with contrast-enhanced stress RT3DE in this subset of patients., Conclusion: Despite some important practical and theoretical benefits, contrast-enhanced stress RT3DE currently has only moderate diagnostic sensitivity due to several technical limitations as temporal and spatial resolution.

Ultrasound contrast has shown to improve endocardial border definition. The purpose of this study was to evaluate the value of contrast agent-enhanced versus non-contrast agent-enhanced real-time 3-dimensional echocardiography (RT3DE) for the assessment of left ventricular (LV) volumes and ejection fraction. Thirty-nine unselected patients underwent RT3DE with and without SonoVue contrast agent enhancement and magnetic resonance imaging (MRI) on the same day. An image quality index was calculated by grading all 16 individual LV segments on a scale of 0 to 4: 0, not visible; 1, poor; 2, moderate; 3, good; and 4, excellent. The 3-dimensional data sets were analyzed offline using dedicated TomTec analysis software. By manual tracing, LV end-systolic volume, LV end-diastolic volume, and LV ejection fraction were calculated. After contrast agent enhancement, mean image quality index improved from 2.4 +/- 1.0 to 3.0 +/- 0.9 (p <0.001). Contrast agent-enhanced RT3DE measurements showed better correlation with MRI (LV end-diastolic volume, r = 0.97 vs 0.86; LV end-systolic volume, r = 0.96 vs 0.94; LV ejection fraction, r = 0.94 vs 0.81). The limits of agreement (Bland-Altman analysis) showed a similar bias for RT3DE images with and without contrast agent but with smaller limits of agreement for contrast agent-enhanced RT3DE. Also, inter- and intraobserver variabilities decreased. In a subgroup, patients with poor to moderate image quality showed an improvement in agreement after administration of contrast agent (+/-24.4% to +/-12.7%) to the same level as patients with moderate to good image quality without contrast agent (+/-10.4%). In conclusion, contrast agent-enhanced RT3DE is more accurate in assessment of LV function as evidenced by better correlation and narrower limits of agreement compared with MRI, as well as lower intra- and interobserver variabilities.

Background: Recent technical developments have resulted in high-resolution real time three-dimensional echocardiography (RT3DE). The purpose of this study was to investigate the beneficial role of parasternal-acquired images in addition to apical-acquired images during contrast stress RT3DE., Methods: The study comprised 30 consecutive patients (52 +/- 11 years, 18 males) with chest pain referred for routine stress testing. The contrast RT3DE images were acquired from the apical and parasternal window with a Sonos 7500 echo system attached to a X4 matrix array transducer., Results: From the apical and parasternal acquisition, 464 segments (91%) and 267 segments (52%) could be analyzed, respectively (P < 0.001). From the apical window, more basal segments were not analyzable (22 of 180, 12% vs. 24 of 330, 7%; P = 0.06). From the parasternal window, more apical segments were not analyzable (117 of 150, 78% vs. 126 of 360, 35%; P < 0.01). The mean image quality index of the 464 analyzable segments from the apical-acquired images was 2.43. Fourteen of 180 basal segments (8%), 12 of 180 midventricular segments (7%) and 2 of 150 apical segment (1%) were only available with parasternal data acquisition. In addition to these 28 segments, 79 segments (15%) already visualized from the apical window improved in quality. The overall mean image quality index, now assessed from 492 (96%) of all segments, using both the apical and parasternal acquired data, improved to 2.74 (P < 0.05)., Conclusions: Addition of parasternal to apical acquisition of contrast RT3DE data can decrease the number of nonvisualized segments and improve mean image quality.

Background: Mitral annulus assessment is of great importance for the diagnosis and treatment of mitral valve disease. The present study sought to assess the value of real-time three-dimensional echocardiography for the assessment of true mitral annulus diameter (MAD)., Methods: One hundred and fifty patients (mean age 38 +/- 18 years) with adequate two-dimensional (2D) echocardiographic image quality underwent assessment of MAD(2D) and MAD(3D) (with real-time three-dimensional echocardiography). In a subgroup of 30 patients true MAD was validated with magnetic resonance imaging (MRI)., Results: There was a good interobserver agreement for MAD(2D) (mean difference = -0.25 +/- 2.90 mm, agreement: -3.16, 2.66) and MAD(3D) (mean difference = 0.29 +/- 2.03, agreement = -1.74, 2.32). Measurements of MAD(2D) and MAD(3D) were well correlated (R = 0.81, P < 0.0001). However, MAD(3D) was significantly larger than MAD(2D) (3.7 +/- 0.9 vs. 3.3 +/- 0.8 cm, P < 0.0001). In the subgroup of 30 patients with MRI validation, MAD(3D) and MAD(MRI) were significantly larger than MAD(2D) (3.3 +/- 0.5 and 3.4 +/- 0.5 cm vs. 2.9 +/- 0.4 cm, both P < 0.001). There was no significant difference between MAD(MRI) and MAD(3D)., Conclusion: MAD(3D) can be reliably measured and is superior to MAD(2D) in the assessment of true mitral annular size.

Objectives: To compare the interobserver variability and accuracy of two different real time three-dimensional echocardiography (RT3DE) analyzing programs., Methods: Forty-one patients (mean age 56 +/- 11 years, 28 men) in sinus rhythm with a cardiomyopathy and adequate 2D image quality underwent RT3DE and magnetic resonance imaging (MRI) within one day. Off-line left ventricular (LV) volume analysis was performed with QLAB V4.2 (semiautomated border detection with biplane projections) and TomTec 4D LV analysis V2.0 (primarily manual tracking with triplane projections and semiautomated border detection)., Results: Excellent correlations (R(2) > 0.98) were found between MRI and RT3DE. Bland-Altman analysis revealed an underestimated LV end-diastolic volume (LV-EDV) for both TomTec (-9.4 +/- 8.7 mL) and QLAB (-16.4 +/- 13.1 ml). Also, an underestimated LV end-systolic volume (LV-ESV) for both TomTec (-4.8 +/- 9.9 mL) and QLAB (-8.5 +/- 14.2 mL) was found. LV-EDV and LV-ESV were significantly more underestimated with QLAB software. Both programs accurately calculated LV ejection fraction (LV-EF) without a bias. Interobserver variability was 6.4 +/- 7.8% vs. 12.2 +/- 10.1% for LV-EDV, 7.8 +/- 9.7% vs. 13.6 +/- 11.2% for LV-ESV, and 7.1 +/- 6.9% vs. 9.7 +/- 8.8% for LV-EF for TomTec vs. QLAB, respectively. The analysis time was shorter with QLAB (4 +/- 2 minutes vs. 6 +/- 2 minutes, P < 0.05)., Conclusions: RT3DE with TomTec or QLAB software analysis provides accurate LV-EF assessment in cardiomyopathic patients with distorted LV geometry and adequate 2D image quality. However, LV volumes may be somewhat more underestimated with the current QLAB software version.

Objective: We evaluated two different commercially available real-time 3-dimensional echocardiographic semiautomated border detection algorithms for left ventricular (LV) volume analysis in patients with cardiomyopathy and distorted LV geometry., Methods: A total of 53 patients in sinus rhythm with various types of cardiomyopathy (mean age 56 +/- 11 years, 28 men) and adequate 2-dimensional image quality were included. The real-time 3-dimensional echocardiographic multiplane interpolation (MI) and full volume reconstruction (FVR) methods were used for LV volume analysis. Magnetic resonance imaging was used as the reference method., Results: A strong correlation (R(2) > 0.95) was found for all LV volume and ejection fraction measurements by either real-time 3-dimensional echocardiographic method. Analysis time was shorter with the FVR method (6 +/- 2 vs 15 +/- 4 minutes, P < .01) as compared with the MI method. Bland-Altman analysis showed greater underestimation of end-diastolic and end-systolic volumes by MI compared with FVR. For the MI method a bias of -24.0 mL (-15.0% of the mean) for end-diastolic volume and -11.3 mL (-18.0% of the mean) for end-systolic volume was found. For FVR analysis these values were -9.9 mL (-6.0% of the mean) and -5.0 mL (-9.0% of the mean), respectively. Ejection fraction was similar for the MI and FVR method with a mean difference compared with magnetic resonance imaging of 0.6 (1.0%) and 0.8 (1.3%), respectively., Conclusion: In patients with cardiomyopathy, distorted LV geometry, and good 2-dimensional image quality, the FVR method is faster and more accurate than the MI method in assessment of LV volumes.

Objective: We sought to assess mitral annular (MA) size and function in hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) using real-time 3-dimensional (3D) echocardiography (RT3DE)., Methods: The study included 30 patients with HCM, 20 patients with DCM, and 30 control subjects. RT3DE measurements included end-systolic and end-diastolic MA area (MAA) (MAA(3D)), MA diameter(3D), MA fractional area change (MAFAC), and MA fractional shortening. In subgroup of 50 patients, magnetic resonance imaging (MRI) was used for MAA(MRI) and MA diameter(MRI) measurement., Results: End-diastolic MAA(3D) was larger in HCM than in control group (P < .0001). Higher MAFAC and MA fractional shortening were present in HCM than in control group (P = .001 and P = .006, respectively). End-systolic and end-diastolic MAA(3D) in DCM were higher than in HCM and control groups (P < .0001). Lower MAFAC and MA fractional shortening were present in DCM than in HCM and control groups (P < .0001). MAFAC correlated well with left ventricular function in control subjects (r = 0.94, P < .0001), whereas correlation was less in DCM (r = 0.53, P = .02) and HCM (r = 0.42, P < .01). RT3DE and MRI measurements were comparable., Conclusion: RT3DE assessment of MA size and function in control subjects and patients with cardiomyopathy is accurate and well correlated with MRI.

For quantification of the left ventricular volume from 3-dimensional echocardiograms a number of cross-sectional images are used. The goal of this study was to determine the minimum number of long-axis images necessary for accurate quantification of the left ventricular volume. A strong correlation was observed between volumes obtained from magnetic resonance imaging and 3-dimensional echocardiography using 16 equiangular images (r = 0.99; y = 0.95x + 3.3 mL; standard error of the estimate = 7.0 mL; N = 30). Comparison of these results with random subsets showed a significant difference for volumes obtained with 4 and 2 equiangular images (P < .005). However, when the subsets were selected to target the eccentric region of the endocardial border this was only the case for subsets of two images (P < .001). This study demonstrates that accurate left ventricular volume quantification can be performed with as little as 8 equiangular long-axis images. By selecting the correctly oriented image set, this number can even be brought down to 4, which will further reduce the analysis time.

Dobutamine stress echocardiography is an accepted tool for the diagnosis of coronary artery disease. Some investigators have claimed that 3-dimensional imaging improves the diagnostic accuracy of dobutamine stress echocardiography. The purpose of the present investigation was to examine the role of contrast echocardiography in the improvement of segmental quality and interobserver agreement during stress real-time 3-dimensional echocardiography (RT3DE). The study comprised 36 consecutive patients with stable chest pain referred for routine stress testing. Three-dimensional images were acquired with an RT3DE system with an X4 matrix-array transducer. All available reconstructed 2-dimensional segments were graded as optimal, good, moderate, or poor. Wall motion was scored as normal, mild hypokinesia, severe hypokinesia, akinesia, or dyskinesia. At peak stress, 466 of the 612 segments (76%) could be analyzed during conventional RT3DE. With contrast-enhanced RT3DE, the number of available segments increased to 553 (90%). The image quality index during conventional RT3DE was 2.2, whereas with contrast-enhanced RT3DE, it was 3.1. With conventional RT3DE, 2 independent observers agreed on the diagnosis of myocardial ischemia in 85 of 108 coronary territories (79%, kappa = 0.26). With contrast-enhanced RT3DE, agreement increased to 95 of 108 coronary territories (88%, kappa = 0.59). Study agreement on myocardial ischemia was present in 26 of 36 studies (72%, kappa = 0.43) with conventional RT3DE and in 32 of 36 studies (89%, kappa = 0.77) with contrast-enhanced RT3DE. In conclusion, during stress RT3DE, contrast-enhanced imaging significantly decreases the number of poorly visualized myocardial segments and improves interobserver agreement for the diagnosis of myocardial ischemia.

Background: The effects of hemodialysis (HD) on left ventricular (LV) function have been studied by various echocardiographic techniques (M-mode, 2D echocardiography). These studies are hampered by a low accuracy of measurements because of geometric assumptions regarding LV shape. Three-dimensional echocardiography (3DE) overcomes this limitation., Methods: We tested the feasibility of 3DE assessment of LV function during HD. Conventional biplane Simpson rule (BSR) and single plane area length method (SPM) for LV function analysis were used as a reference., Results: 12 HD patients were studied and in 10 (83%) a total of 80 3D datasets were acquired. In 3 patients, one dataset (4%) was of insufficient quality and excluded from analysis. Correlation between SPM, BSR and 3DE for calculation of end-diastolic (EDV, r = 0.89 and r = 0.92, respectively), end-systolic volume (ESV, r = 0.92 and r = 0.93, respectively) and for ejection fraction (EF, r = 0.90 and r = 0.88, respectively) was moderate. Limits-of-agreement results for EDV and ESV were poor with confidence intervals larger than 30 ml. Both 2DE methods underestimated end-diastolic and end-systolic volume, while overestimating ejection fraction., Conclusion: 3DE is feasible for image acquisition during HD, which opens the possibility for accurate and reproducible measurement of LV function during HD. This may improve the assessment of the acute effect of HD on LV performance, and guide therapeutic strategies aimed at preventing intradialytic hypotension., ((c) 2007 S. Karger AG, Basel.)

Although the advantages of three-dimensional (3-D) echocardiography have been acknowledged, its application for routine diagnosis is still very limited. This is mainly due to the relatively long acquisition time. Only recently has this problem been addressed with the introduction of new real-time 3-D echo systems. This paper describes the design, characteristics, and capabilities of an alternative concept for rapid 3-D echocardiographic recordings. The presented fast-rotating ultrasound (FRU)-transducer is based on a 64-element phased array that rotates with a maximum speed of 8 Hz (480 rpm). The large bandwidth of the FRU-transducer makes it highly suitable for tissue and contrast harmonic imaging. The transducer presents itself as a conventional phased-array transducer; therefore, it is easily implemented on existing 2-D echo systems, without additional interfacing. The capabilities of the FRU-transducer are illustrated with in-vitro volume measurements, harmonic imaging in combination with a contrast agent, and a preliminary clinical study.

Measurement of left ventricular (LV) volume and function are the most common clinical referral questions to the echocardiography laboratory. A fast, practical, and accurate method would offer important advantages to obtain this important information. To validate a new practical method for rapid measurement of LV volume and function. We developed a continuous fast-rotating transducer, with second-harmonic capabilities, for three-dimensional echocardiography (3DE). Fifteen cardiac patients underwent both 3DE and magnetic resonance imaging (reference method) on the same day. 3DE image acquisition was performed during a 10-second breath-hold with a frame rate of 100 frames/sec and a rotational speed of 6 rotations/sec. The individual images were postprocessed with Matlab software using multibeat data fusion. Subsequently, with these images, 12 datasets per cardiac cycle were reconstructed, each comprising seven equidistant cross-sectional images for analysis in the new TomTec 4DLV analysis software, which uses a semi-automated border detection (ABD) algorithm. The ABD requires an average analysis time of 15 minutes per patient. A strong correlation was found between LV end-diastolic volume (r = 0.99; y = 0.95x - 1.14 ml; SEE = 6.5 ml), LV end-systolic volume (r = 0.96; y = 0.89x + 7.91 ml; SEE = 7.0 ml), and LV ejection fraction (r = 0.93; y = 0.69x + 13.36; SEE = 2.4%). Inter- and intraobserver agreement for all measurements was good. The fast-rotating transducer with new ABD software is a dedicated tool for rapid and accurate analysis of LV volume and function.

Objective: The purpose of this study was to assess the (1) feasibility of real-time three-dimensional echocardiography (RT-3DE) data acquisition and (2) volumes and function of the abnormal left ventricle (LV) in adult patients with congenital heart disease (CHD), compared with magnetic resonance imaging (MRI) data., Methods: Thirty-two patients (59% were male) with CHD were evaluated on the same day by MRI and RT-3DE. Acquisition of RT-3DE data sets was feasible in 29 of the 32 patients (91%). The time of 3D data acquisition was 4 +/- 2 minutes, and LV analysis was 17 +/- 5 minutes per patient for manual border tracing., Results: A good correlation was observed between RT-3DE with manual border detection and MRI for LV end-diastolic volume (r = 0.97), LV end-systolic volume (r = 0.98), and LV ejection fraction (r = 0.94)., Conclusion: RT-3DE is feasible for volumetric analysis of the abnormal LV allowing accurate determination of LV volume and ejection fraction compared with MRI in adult patients with CHD.

This is the first study to assess the feasibility and accuracy of real-time 3-dimensional echocardiography (RT-3DE) for the measurements of left ventricular (LV) mass in patients with congenital heart disease (CHD) compared with magnetic resonance imaging (MRI). Twenty patients (60% men) with CHD were evaluated by MRI and RT-3DE on the same day. Their mean age was 29 +/- 8 years (range 19 to 49). RT-3DE was performed with a Philips Sonos 7500 echocardiographic system and LV mass analyses with the assistance of TomTec software. The results for LV mass obtained by manual tracing were compared with Signa 1.5-T MRI data. The acquisition of RT-3DE data sets was feasible in all 20 patients. Nine patients (45%) had good, 5 patients (25%) moderate, and 6 patients (30%) poor image quality of the 3-dimensional data set. The time of 3-dimensional data acquisition was 4 +/- 2 minutes. Off-line image processing and tracing required approximately 11 +/- 3 minutes. A very good correlation was observed between RT-3DE data with sufficient image quality and MRI (r = 0.98, y = 0.96x + 4.1, SEE 9.8 g), with a mean difference of 2.0 +/- 20 g. Interobserver agreement was excellent (r = 0.99, y = 0.97x + 3.81), with a mean difference of -1 +/- 11 g. In conclusion, the assessment of LV mass from RT-3DE data is feasible in patients with CHD. The mass of an abnormally shaped left ventricle can be determined with high accuracy and low interobserver variability in patients with good or moderate echocardiographic image quality.

Rationale and Objectives: We propose a semiautomatic endocardial border detection method for three-dimensional (3D) time series of cardiac ultrasound (US) data based on pattern matching and dynamic programming, operating on two-dimensional (2D) slices of the 3D plus time data, for the estimation of full cycle left ventricular volume, with minimal user interaction., Materials and Methods: The presented method is generally applicable to 3D US data and evaluated on data acquired with the Fast Rotating Ultrasound (FRU-) Transducer, developed by Erasmus Medical Center (Rotterdam, the Netherlands), a conventional phased-array transducer, rotating at very high speed around its image axis. The detection is based on endocardial edge pattern matching using dynamic programming, which is constrained by a 3D plus time shape model. It is applied to an automatically selected subset of 2D images of the original data set, for typically 10 equidistant rotation angles and 16 cardiac phases (160 images). Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastole and end-systole volumes. Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastolic (ED) and end-systolic (ES) volumes., Results: The semiautomatic border detection approach shows good correlations with MRI ED/ES volumes (r = 0.938) and low interobserver variability (y = 1.005x - 16.7, r = 0.943) over full-cycle volume estimations. It shows a high consistency in tracking the user-defined initial borders over space and time., Conclusions: We show that the ease of the acquisition using the FRU-transducer and the semiautomatic endocardial border detection method together can provide a way to quickly estimate the left ventricular volume over the full cardiac cycle using little user interaction.

Three-dimensional (3-D) echocardiography has been an important research goal ever since the introduction of two-dimensional (2-D) echocardiography. Most approaches towards 3-D echocardiography were off-line and based on the sequential rotational scanning and acquisition of multiple cross-sectional images together with external or internal reference systems. These approaches were limited by long acquisition and analysis time in combination with poor image quality. Recently, improvements in the matrix array technology have significantly increased spatial and temporal resolution of second-generation real-time 3-D transducers. Clinical use of modern 3-D echocardiography is boosted by the marked reduction in acquisition time and the unique possibility of on-line rendering on the ultrasound system. The integration and future quantification of new parameters together with on-line review allows new insights into cardiac function, morphology and synchrony that offer great potentials in the evaluation of right and left global and regional function, diagnosis of small areas of ischemia, congenital and valvular heart disease and effects of biventricular pacing in dilated heart asynchrony. This report will review current and future applications of 3-D data acquisition, emphasizing the real-time methods and clinical applications of the new matrix array transducer.

Objective: To assess a new approach for guiding and hemodynamic optimization of resynchronization therapy, using three-dimensional (3D) transthoracic echocardiography., Background: Resynchronization therapy for heart failure provides the greatest hemodynamic benefit when applied to the most delayed left ventricular (LV) site. Currently, the ideal LV pacing site is selected according to acute invasive hemodynamic assessment and/or tissue Doppler imaging., Methods: A total of 16 patients with advanced heart failure and an implanted biventricular pacemaker were included in this study. Transthoracic apical LV images at equidistant intervals were obtained using a prototype, fast-rotating second harmonic transducer to reconstruct 3D LV datasets during sinus rhythm (SR), right ventricular (RV) apical and biventricular pacing mode. A semi-automated contour analysis system (4D LV analysis, TomTec, Germany) was used for segmental wall motion analysis and identification of the most delayed contracting segment and calculation of global LV function., Results: Data acquisition duration was 10 s and analyzable 3D images were obtained in 12 patients. Of these patients, data during SR were available in 9 and during biventricular pacing in 11. The greatest contraction delay during SR was found in the anterior and antero-septal segments in five of nine patients. Biventricular pacing resulted in reduction of the contraction delay in seven of eight patients. The global LV function did not change significantly., Conclusion: 3D echocardiography with appropriate analytic software allows detection of the most delayed LV contracting segment and can be used to select the optimal pacing site during resynchronization therapy.

Improved endocardial border delineation with the application of contrast agents should allow for less complex and faster tracing algorithms for left ventricular volume analysis. We developed a fast rotating phased array transducer for 3D imaging of the heart with harmonic capabilities making it suitable for contrast imaging. In this study the feasibility of 3D harmonic contrast imaging is evaluated in vitro. A commercially available tissue mimicking flow phantom was used in combination with Sonovue. Backscatter power spectra from a tissue and contrast region of interest were calculated from recorded radio frequency data. The spectra and the extracted contrast to tissue ratio from these spectra were used to optimize the excitation frequency, the pulse length and the receive filter settings of the transducer. Frequencies ranging from 1.66 to 2.35 MHz and pulse lengths of 1.5, 2 and 2.5 cycles were explored. An increase of more than 15 dB in the contrast to tissue ratio was found around the second harmonic compared with the fundamental level at an optimal excitation frequency of 1.74 MHz and a pulse length of 2.5 cycles. Using the optimal settings for 3D harmonic contrast recordings volume measurements of a left ventricular shaped agar phantom were performed. Without contrast the extracted volume data resulted in a volume error of 1.5%, with contrast an accuracy of 3.8% was achieved. The results show the feasibility of accurate volume measurements from 3D harmonic contrast images. Further investigations will include the clinical evaluation of the presented technique for improved assessment of the heart.

Simultaneous electrical stimulation of both ventricles in patients with interventricular conduction disturbance and advanced heart failure improves hemodynamics and results in increased exercise tolerance, quality of life. We have developed a novel technique for the assessment and optimization of resynchronization therapy. Our approach is based on transthoracic dynamic three-dimensional (3D) echocardiography and allows determination of the most delayed contraction site of the left ventricle (LV) together with global LV function data. Our initial results suggest that fast reconstruction of the LV is feasible for the selection of the optimal pacing site and allows identifying LV segments with dyssynchrony.

Accurate determination of LV volume, ejection fraction and segmental wall motion abnormalities is important for clinical decision-making and follow-up assessment. Currently, echocardiography is the most common used method to obtain this information. Three-dimensional echocardiography has shown to be an accurate and reproducible method for LV quantitation, mainly by avoiding the use of geometric assumptions. In this review, we describe various methods to acquire a 3D-dataset for LV volume and wall motion analysis, including their advantages and limitations. We provide an overview of studies comparing LV volume and function measurement by various gated and real-time methods of acquisition compared to magnetic resonance imaging. New technical improvements, such as automated endocardial border detection and contrast enhancement, will make accurate on-line assessment with little operator interaction possible in the near future.