Accuracy and feasibility of online 3-dimensional echocardiography for measurement of left ventricular parameters

A graphical analysis of aspects contributing to the spreading of measurements of left ventricular function

The Simpson's method is the standard technique to determine left ventricular (LV) ejection fraction (EF) on echocardiography. The large inter-observer variability of measuring LVEF is well documented but not fully understood. A graphical analysis was used to elaborate what contributes to the inter-observer difference. Forty-two cardiologists (32 male, 39 ± 7 years) evaluated the LVEF using the Simpson's method on 15 different echocardiograms (2 and 4 chamber view (2CH/4CH)); the program did not show the result of EF to prevent a bias. End-diastolic (ED) and end-systolic (ES) frames were predefined ensuring measurement at the same time point of the cardiac cycles. After standardization of the LV contour, the differences of the individual contours compared to a reference contour were measured. Also, the spreading of lateral/medial mitral annulus contours and the apex were depicted. A significant spreading of LV-contours was seen with larger contours leading to higher EFs (p < 0.001). Experience did not influence the determination of LVEF. ED-volumes showed more spreading than ES-volumes ((3.6 mm (IQR: 2.6-4.0) vs. 3.4 mm (IQR: 2.8-3.8), p < 0.001). Also, the differences were larger for the 2CH compared to the 4CH (p < 0.001). Variability was significantly larger for lateral than septal wall (p < 0.001) as well as the anterior compared to the inferior wall (p < 0.001). There was a relevant scattering of the apex and medial/ lateral mitral annulus ring. There was a large variability of LV-volumes and LVEF as well as position of mitral valve ring and apex. There were global differences (apical 2CH or 4CH), regional aspects (LV walls) and temporal factors (ED vs. ES). Thus, multiple factors contributed to the large variability.Trial registration: The study was registered at "Netherlands Trial Register" ( www.trialregister.nl ; study number: NL5131).

3-D Echocardiography Is Feasible and More Reproducible than 2-D Echocardiography for In-Training Echocardiographers in Follow-up of Patients with Heart Failure with Reduced Ejection Fraction

Left ventricular volumes (LVVs) and ejection fraction (LVEF) are key elements in the evaluation and follow-up of patients with heart failure with reduced ejection fraction (HFrEF). Therefore, a feasible and reproducible imaging method to be used by both experienced and in-training echocardiographers is mandatory. Our aim was to establish if, in a large echo lab, echocardiographers in-training provide feasible and more reproducible results for the evaluation of patients with HFrEF when using 3-dimensional echocardiography (3-DE) versus 2-dimensional echocardiography (2-DE). Sixty patients with HFrEF (46 males, age: 58 ± 17 y) underwent standard transthoracic 2-D acquisitions and 3-D multibeat full volumes of the left ventricle. One expert user in echocardiography (expert) and three echocardiographers with different levels of training in 2-DE (beginner, medium and advanced) measured the 2-D LVVs and LVEFs on the same consecutive images of patients with HFrEF. Afterward, the expert performed a 1-mo training in 3-DE analysis of the users, and both the expert and trainees measured the 3-D LVVs and LVEF of the same patients. Measurements provided by the expert and all trainees in echo were compared. Six patients were excluded from the study because of poor image quality. The mean end-diastolic LVV of the remaining 54 patients was 214 ± 75 mL with 2-DE and 233 ± 77 mL with 3-DE. Mean LVEF was 35 ± 10% with 2-DE and 33 ± 10% with 3-DE. Our analysis revealed that, compared with the expert user, the trainees had acceptable reproducibility for the 2-DE measurements, according to their level of expertise in 2-DE (intra-class coefficients [ICCs] ranging from 0.75 to 0.94). However, after the short training in 3-DE, they provided feasible and more reproducible measurements of the 3-D LVVs and LVEF (ICCs ranging from 0.89-0.97) than they had with 2-DE. 3-DE is a feasible, rapidly learned and more reproducible method for the assessment of LVVs and LVEF than 2-DE, regardless of the basic level of expertise in 2-DE of the trainees in echocardiography. In echo labs with a wide range of staff experience, 3-DE might be a more accurate method for the follow-up of patients with HFrEF.

Performance of a new fully automated transthoracic three-dimensional echocardiographic software for quantification of left cardiac chamber size and function: Comparison with 3 Tesla cardiac magnetic resonance

PURPOSE

To evaluate the accuracy and reproducibility of a new fully automated fast three-dimensional (3D) transthoracic echocardiography (TTE) software for the simultaneous assessment of left atrial (LA) volumes and LA ejection fraction (EF), left ventricular (LV) volumes, LV mass, and LVEF, and to compare the results obtained with a cardiac magnetic resonance (CMR) reference.

METHODS

We included retrospectively 56 patients (46 men; mean age 63 ± 13 years) in sinus rhythm who had had comprehensive 3D TTE and CMR examinations within 24 hours.

RESULTS

Despite a slight underestimation of LV and LA volumes, LVEF and LAEF were similar using CMR or 3DTTE (58% ± 16% vs 58% ± 12%; P = .65 and 45% ± 14% vs 46% ± 15%; P = .38, respectively) in the total population. Despite significant correlation between TTE and CMR measurements (r = 0.78; P < .001), 3D TTE underestimated LV mass (bias = -27 ± 35 g).

CONCLUSION

3D TTE using a new-generation fully automated software is a fast and reproducible imaging modality for simultaneous extensive quantification of left heart chambers size and function in routine practice. Potential underestimation of LA volume and LV mass, and of LVEF in patients with LVEF <50%, should be taken into consideration.

Cardiac MRI for the evaluation of oncologic cardiotoxicity

Cancer therapeutics-related cardiac dysfunction (CTRCD) is a well-established adverse effect resulting from a number of cancer therapeutics. Newer immunotherapy has been associated with cardiomyopathy and myocarditis making comprehensive imaging useful for early recognition. Cardiac MRI (CMR) offers a comprehensive evaluation to detect CTRCD. Established guidelines for monitoring left ventricular ejection fraction for potential cardiotoxicity have recently incorporated CMR. We will review the utility of CMR in contemporary evaluation for potential oncologic cardiotoxicity.

Left ventricular volumes and ejection fraction quantification using an automated three-dimensional adaptive analytic echocardiographic algorithm in pediatric population

INTRODUCTION

The quantitative measurement of the left ventricle by echocardiography is a fundamental tool in the diagnosis and prognosis of acquired and congenital diseases in the pediatric population. The objective of this study was to validate an automated three-dimensional adaptive analytic echocardiographic algorithm, the so-called Heart Model^® (HM) in the pediatric population, using as comparators the left atrial and left ventricular volumes and left ventricular ejection fraction obtained by means of conventional 2D and 3D echocardiography.

METHODS

Pilot study, where a population comprised of 75 consecutive patients aged 6-17 years who attended a pediatric cardiology clinic, was evaluated. Every patient underwent a conventional 2D and 3D echocardiography and an analysis using HM. Conventional 3D echo was used as the reference method.

RESULTS

Seventy-five patients were analyzed. Mean age was 11.2 (4.0) years (52.2% women). The intraclass correlation coefficient of HM vs 2D echo was poor, but it was good for the agreement between HM and 3D echo for left ventricular end-diastolic volume (ICC: 0.98; 95% CI: 0.97-0.99; P < 0.001), left ventricular end-systolic volume ICC: 0.98; 95% CI: 0.96-0.99; P = 0.001), and left ventricular ejection fraction (ICC: 0.87; 95% CI: 0.78-0.92; P < 0.001). The agreement was also good for the three parameters when the analysis was performed according to body weight.

CONCLUSIONS

Heart Model^® is a feasible and accurate tool for the evaluation of left atrial and left ventricular volumes and left ventricular ejection fraction in pediatric population aged above 6 years.

Realization of fully automated quantification of left ventricular volumes and systolic function using transthoracic 3D echocardiography

BACKGROUND

Study on automated three-dimensional (3D) quantification of left heart parameters by using Heartmodel software is still in the early stage and fully automatic analysis was not clearly achieved. The aim of our study was to evaluate the performance of this new technology in measuring left ventricular (LV) volume and ejection fraction (EF) in patients with a variety of heart diseases on the basis of rationally determining the default endocardial border values.

METHODS

Subjects with a variety of heart diseases were included prospectively. High quality Heartmodel images were selected to determine the end-diastolic and end-systolic default values of endocardial border. The accuracy and reproducibility of automated three-dimensional echocardiography (3DE) for measuring LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF were evaluated with the traditional manual 3DE as the relative standard.

RESULTS

Ninety seven subjects were enrolled in the study. The default endocardial border values were determined as 66% and 40% for end-diastole (ED) and end-systole (ES), respectively. Most of the subjects (84/97) were automatically analyzed by Heartmodel software without manual adjustment, revealing a close correlation of automated 3DE with manual 3DE in measuring EDV, ESV and EF (r-values: EDV: 0.96, ESV: 0.97, EF: 0.96). The EDV and ESV values obtained by automated 3DE were higher than those measured by manual 3DE (biases: EDV: 16 ± 18 ml, ESV: 11 ± 12 ml). The intra- and inter-observer reproducibility of automated 3DE was better than that of manual 3DE. Automated 3DE with manual adjustment showed good consistency with manual 3DE in assessing the impairment degree of systolic function in patients with wall motion abnormalities (n = 58), (Kappa = 0.74, P = 0.00).

CONCLUSION

Fully automated 3DE quantification of LV volume and EF could be achieved in most patients. Since automated 3DE was accurate and more reproducible, it could replace the existing manual 3DE technology and be routinely used in clinical practice.

Cardiac Imaging: Multimodality Advances and Surveillance Strategies in Detection of Cardiotoxicity

Contemporary cancer management has increased the overall number of cancer survivors, but cardiotoxicity remains a subject of concern, which is a major cause of noncancer mortality among survivors. Among the potential cardiovascular complications, left ventricular (LV) systolic dysfunction is a poor prognostic factor. The importance of its early detection is based on the principle that the likelihood of response to heart failure (HF) treatment is temporally related to the initiation of HF treatment. For these reasons, cardiac monitoring is commonly applied in general practice, based on serial measurements of LV ejection fraction (LVEF); transthoracic echocardiography (TTE) is generally used. However, the LVEF, as a diagnostic and predictive parameter, has significant limitations, which calls for more effective multimodality imaging strategies. This approach requires further study, but there is increasing available data in the literature, encouraging the combination of multimodality imaging parameters and techniques for early cancer therapeutic-related cardiac dysfunction (CTRCD) detection.

Assessment of left atrium and diastolic dysfunction in patients with hypertensive retinopathy: A real-time three-dimensional echocardiography-based study

The fundoscopic examination of hypertensive patients, which is established hypertension-related target organ damage (TOD), tends to be underutilized in clinical practice. We sought to investigate the relationship between retinal alterations and left atrium (LA) volumes by means of real-time three-dimensional echocardiography (RT3DE). Our population consisted of 88 consecutive essential hypertensive patients (age 59.2 ± 1.2 years, 35 males). All subjects underwent a fundoscopy examination and were distributed into four groups according to the Keith-Wagener-Barker (KWB) classification. The four groups (KWB grades 0-3: including 26, 20, 26, and 16 patients, respectively) did not differ with regard to age, gender, or metabolic profile. There were no significant differences between groups with regard to parameters reflecting LV systolic function and diastolic dysfunction (DD) in two-dimensional echocardiography (2DE). Nevertheless, patients in the higher KWB category had higher values of LA volumes (LA maximal volume index, LA minimal volume index, preatrial contraction volume index, LA total stroke volume index, LA active stroke volume index, p < 0.001) regarding RT3DE. There is also a significant relationship between LA active stroke volume index (ASVI) and duration of hypertension (HT) (r: 0.68, p < 0.001). In the logistic regression analysis, ASVI was independent predictors of LV DD in patients with arterial hypertension (HT). Patients with arterial HT were found to have increased LA volumes and impaired diastolic functions. Assessment of the arterial HT patient by using RT3DE atrial volume analysis may facilitate early recognition of TOD, which is such a crucial determinant of cardiovascular mortality and morbidity.

Patient movement compensation for 3D echocardiography fusion

Limited field of view (FOV) is a major problem for 3D real-time echocardiography (3DRTE), which results in an incomplete representation of cardiac anatomy. Various image registration techniques have been proposed to improve the field of view in 3DRTE by fusing multiple image volumes. However, these techniques require significant overlap between the individual volumes and rely on high image resolution and high signal-to-noise ratio. Changes in the heart position due to patient movement during image acquisition can also reduce the quality of image fusion. In this paper, we propose a multi-camera based optical tracking system which 1) eliminates the need for image overlap and 2) compensates for patient movement during acquisition. We compensate for patient movement by continuously tracking the patient position using skin markers and incorporating this information into the fusion process. We fuse volumes acquired during R-R wave peaks based on Electrocardiogram (ECG) data to account for retrospective image acquisition. The fusion technique was validated using a heart phantom (Shelley Medical Imaging Technologies) and on one healthy volunteer. The fused ultrasound volumes could be generated in within 2 seconds and were found to have complete myocardial boundaries alignment upon visual assessment. No stitching artefacts or movement related artefacts were observed in the fused image.

Real-time three-dimensional left ventricular contraction in patients with diastolic dysfunction

PURPOSE

Systolic alterations in left ventricular (LV) myocardial function have been reported previously in patients with diastolic dysfunction (DD). Recent advances in real-time three-dimensional echocardiography (3DE) enable the measurement of a set of parameters previously difficult to obtain with standard two-dimensional echocardiography (2DE). The aim of this study was to evaluate global 3DE LV contraction in patients with and without DD who had normal ejection fraction (EF).

METHODS

Sixty-five patients (average age 56 ± 6 years; 31 females and 34 males) with normal EF (>50 %) referred to echocardiographic examination for the evaluation of DD were included. In addition to measuring conventional echocardiographic parameters, they were also evaluated with 3DE. End diastolic volume, end systolic volume, EF, corrected standard deviation (SD) of time to minimal systolic volume for 16 segments its dispersion, average excursion of the segments and the SD of segmental motion (excursion-SD) were recorded.

RESULTS

When we tested the differences among three groups of diastolic function (normal, Grade 1, and Grade 2), the results showed that coronary artery disease, left atrial volume, septum, posterior wall, E, A, E/A, deceleration time, E' septum, E' lateral, and excursion-SD were significantly different. An ordered logistic regression analysis revealed that excursion-SD (p < 0.001) and septum (p < 0.001) measurements were statistically significant for predicting DD grade.

CONCLUSION

In our patient population, a decline in excursion-SD values was observed with increasing DD grade. In other words, the amount of segmental difference in terms of excursion was reduced.

Advanced Echocardiographic Techniques in Detection of Cardiotoxicity

OPINION STATEMENT

As advancements are made in cancer treatment, there is an increasing recognition of the cardiotoxic potential of chemotherapies and the need to monitor for the development of cardiac dysfunction in survivors. Echocardiography is the cornerstone of cardiac imaging and provides a feasible and non-invasive method to assess cardiac dysfunction in patients with cancer. In recent years, there has been increasing research in echocardiographic techniques to improve diagnosis of cardiotoxicity, including a more accurate assessment of the left ventricular function and the detection of subclinical disease. These specialized techniques include stress and contrast echocardiography, three-dimensional echocardiography, diastolic dysfunction, tissue Doppler imaging, and strain parameters.

A feasible method for non-invasive measurement of pulmonary vascular resistance in pulmonary arterial hypertension: Combined use of transthoracic Doppler-echocardiography and cardiac magnetic resonance. Non-invasive estimation of pulmonary vascular resistance

BACKGROUND

Transthoracic Doppler-echocardiography (TTE) can estimate mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) reliably, and cardiac magnetic resonance (CMR) is the best modality for non-invasive measurement of cardiac output (CO). We speculated that the combined use of TTE and CMR could provide a feasible method for non-invasive measurement of pulmonary vascular resistance (PVR) in pulmonary arterial hypertension (PAH).

METHODS AND RESULTS

Right heart catheterization (RHC) was undertaken in 77 patients (17M/60F) with PAH, and simultaneous TTE was carried out to evaluate MPAP, PCWP and CO. Within 2 days, CO was measured again with CMR in similar physiological status. Then, PVR was calculated with the integrated non-invasive method: TTE-derived (MPAP-PCWP)/CMR-derived CO and the isolated TTE method: TTE-derived (MPAP-PCWP)/TTE-derived CO, respectively. The PVR calculated with integrated non-invasive method correlated well with RHC-calculated PVR (r = 0.931, 95% confidence interval 0.893 to 0.956). Between the integrated non-invasive PVR and RHC-calculated PVR, the Bland-Altman analysis showed the satisfactory limits of agreement (mean value: - 0.89 ± 2.59). In comparison, the limits of agreement were less satisfactory between TTE-calculated PVR and RHC-calculated PVR (mean value: - 1.80 ± 3.33). Furthermore, there were excellent intra- and inter-observer correlations for the measurements of TTE and CMR (P < 0.001 for all).

CONCLUSIONS

The combined use of TTE and CMR provides a clinically reliable method to determine PVR non-invasively. In comparison with RHC, the integrated method shows good accuracy and repeatability, which suggests the potential for the evaluation and serial follow-up in patients with PAH.

TRANSLATIONAL PERSPECTIVE

In PAH, the non-invasive measurement of PVR is very important in clinical practice. Up to now, however, the widely accepted non-invasive method is still unavailable. Since TTE can estimate (MPAP-PCWP) reliably and CMR is the best image modality for the measurement of CO, the combined use of two modalities has the potential to determine PVR non-invasively. In this research, the integrated non-invasive method showed good diagnostic accuracy and repeatability compared with RHC. Therefore, it might be a feasible method for non-invasive measurement of PVR in patients with PAH.

Cancer and cardiovascular disease: the use of novel echocardiography measures to predict subsequent cardiotoxicity in breast cancer treated with anthracyclines and trastuzumab

As the population of breast cancer survivors grows, it has become evident that chemotherapy has significant cardiotoxic side effects. Echocardiography is a noninvasive, cost-effective, and widely available imaging tool that is well positioned to serve as a primary modality for monitoring chemotherapy-induced cardiotoxicity. Although left ventricular ejection fraction is a standard measurement by which to monitor chemotherapy-induced cardiotoxicity, its predictive value in identifying subsequent cardiotoxicity is limited. More sophisticated echocardiography modalities may offer improved sensitivity and specificity for detecting chemotherapy-induced cardiotoxicity. These include tissue Doppler imaging measures, newer techniques based upon two- and three-dimensional strain and torsion analysis, and three-dimensional measures of cardiac size. While these modalities are not all currently part of clinical practice, a body of data supporting their use is steadily building. More research remains to be performed, and noninvasively detecting cancer therapy-induced cardiac dysfunction at the earliest stages is of increasing interest.

Left atrial expansion index is an independent predictor of diastolic dysfunction in patients with preserved left ventricular systolic function: a three dimensional echocardiography study

In the absence of mitral valve disease left atrial (LA) volume is a marker of diastolic dysfunction and its severity. This study investigated the relationship between left ventricular (LV) end diastolic pressure (LVEDP) and LA volumes and phasic atrial functions detected by real-time full volume three-dimensional echocardiography (RT3DE), in a patient population with preserved LV systolic function. Seventy-two (39 female and 33 male; mean age 56.1 ± 9.0 years) stable patients with normal LV ejection fraction (EF) undergoing cardiac catheterization were studied. All patients underwent comprehensive echocardiographic examination just before catheterization and LVEDP was obtained. In addition to conventional echocardiographic measurements and Doppler indices; by using RT3DE LA maximum, minimum and pre-a-wave volumes were measured; LA total, passive and active emptying volumes and fractions were calculated. LV systolic function was assessed by EF and global longitudinal strain by speckle tracking. RT3DE minimum LA volume index, RT3DE active LAEF and LA expansion index (EI) were statistically significant univariate predictors of LVEDP ≥ 16 mmHg. When age and hypertension adjusted multivariate analysis was performed EI [β = -1.741, p = 0.015; OR 0.175; 95 % CI (0.043-0.717)] was an independent predictor of elevated LVEDP. RT3DE evaluation of LA function during entire cardiac cycle has incremental value for the diagnosis of diastolic dysfunction in patients with preserved EF. We suggest that RT3DE evaluation of LA may find clinical application in this field.

Left ventricular ejection fraction and volumes: it depends on the imaging method

Background and Methods

In order to provide guidance for using measurements of left ventricular (LV) volume and ejection fraction (LVEF) from different echocardiographic methods a PubMed review was performed on studies that reported reference values in normal populations for two-dimensional (2D ECHO) and three-dimensional (3D ECHO) echocardiography, nuclear imaging, cardiac computed tomography, and cardiac magnetic resonance imaging (CMR). In addition all studies (2 multicenter, 16 single center) were reviewed, which included at least 30 patients, and the results compared of noncontrast and contrast 2D ECHO, and 3D ECHO with those of CMR.

Results

The lower limits for normal LVEF and the normal ranges for end-diastolic (EDV) and end-systolic (ESV) volumes were different in each method. Only minor differences in LVEF were found in studies comparing CMR and 2D contrast echocardiography or noncontrast 3D echocardiography. However, EDV and ESV measured with all echocardiographic methods were smaller and showed greater variability than those derived from CMR. Regarding agreement with CMR and reproducibility, all studies showed superiority of contrast 2D ECHO over noncontrast 2D ECHO and 3D ECHO over 2D ECHO. No final judgment can be made about the comparison between contrast 2D ECHO and noncontrast or contrast 3D ECHO.

Conclusion

Contrast 2D ECHO and noncontrast 3D ECHO show good reproducibility and good agreement with CMR measurements of LVEF. The agreement of volumes is worse. Further studies are required to assess the clinical value of contrast 3D ECHO as noncontrast 3D ECHO is only reliable in patients with good acoustic windows.

Reproducibility of echocardiographic techniques for sequential assessment of left ventricular ejection fraction and volumes: application to patients undergoing cancer chemotherapy

OBJECTIVES

The aim of this study was to identify the best echocardiographic method for sequential quantification of left ventricular (LV) ejection fraction (EF) and volumes in patients undergoing cancer chemotherapy.

BACKGROUND

Decisions regarding cancer therapy are based on temporal changes of EF. However the method for EF measurement with the lowest temporal variability is unknown.

METHODS

We selected patients in whom stable function in the face of chemotherapy for breast cancer was defined by stability of global longitudinal strain (GLS) at up to 5 time points (baseline, 3, 6, 9, and 12 months). In this way, changes in EF were considered to reflect temporal variability of measurements rather than cardiotoxicity. A comprehensive echocardiogram consisting of 2-dimensional (2D) and 3-dimensional (3D) acquisitions with and without contrast administration was performed at each time point. Stable LV function was defined as normal GLS (≤-16.0%) at each examination. The EF and volumes were measured with 2D-biplane Simpson's method, 2D-triplane, and 3-dimensional echocardiography (3DE) by 2 investigators blinded to any clinical data. Inter-, intra-, and test-retest variability were assessed in a subgroup. Variability was assessed by analysis of variance and compared with Levene's or t test.

RESULTS

Among 56 patients (all female, 54 ± 13 years of age), noncontrast 3D EF, end-diastolic volume, and end-systolic volume had significantly lower temporal variability than all other methods. Contrast only decreased the temporal variability of LV end-diastolic volume measurements by the 2D biplane method. Our data suggest that a temporal variability in EF of 0.06 might occur with noncontrast 3DE due to physiological differences and measurement variability, whereas this might be >0.10 with 2D methods. Overall, 3DE also had the best intra- and inter-observer as well as test-retest variability.

CONCLUSIONS

Noncontrast 3DE was the most reproducible technique for LVEF and LV volume measurements over 1 year of follow-up.

Advanced echocardiographic techniques

Echocardiography has advanced significantly since its first clinical use. The move towards more accurate imaging and quantification has driven this advancement. In this review, we will briefly focus on three distinct but important recent advances, three‐dimensional (3D) echocardiography, contrast echocardiography and myocardial tissue imaging. The basic principles of these techniques will be discussed as well as current and future clinical applications.

Feasibility, accuracy, and reproducibility of real-time full-volume 3D transthoracic echocardiography to measure LV volumes and systolic function: a fully automated endocardial contouring algorithm in sinus rhythm and atrial fibrillation

OBJECTIVES

To assess the feasibility, accuracy, and reproducibility of real-time full-volume 3-dimensional transthoracic echocardiography (3D RT-VTTE) to measure left ventricular (LV) volumes and ejection fraction (EF) using a fully automated endocardial contouring algorithm and to identify and automatically correct the contours to obtain accurate LV volumes in sinus rhythm and atrial fibrillation (AF).

BACKGROUND

3D transthoracic echocardiography is not used routinely to quantify LV volumes and EF. A fully automated workflow using RT-VTTE may improve clinical adoption.

METHODS

RT-VTTE was performed and 3D EF and volumes obtained using an automated trabecular endocardial contouring algorithm; an automated correction was applied to track the compacted myocardium. Cardiac magnetic resonance (CMR) and 2-dimensional biplane Simpson method were the reference standard.

RESULTS

Ninety-one patients (67 in normal sinus rhythm [NSR], 24 in AF) were included. Among all NSR patients, there was excellent correlation between RT-VTTE and CMR for end-diastolic volume (EDV), end-systolic volume (ESV), and EF (r = 0.90, 0.96, and 0.98, respectively; p < 0.001). In patients with EF ≥50% (n = 36), EDV and ESV were underestimated by 10.7 ± 17.5 ml (p = 0.001) and by 4.1 ± 6.1 ml (p < 0.001), respectively. In those with EF <50% (n = 31), EDV and ESV were underestimated by 25.7 ± 32.7 ml (p < 0.001) and by 16.2 ± 24.0 ml (p = 0.001). Automated contour correction to track the compacted myocardium eliminated mean volume differences between RT-VTTE and CMR. In patients with AF, LV volumes and EF were accurate by RT-VTTE (r = 0.94, 0.94, and 0.91 for EDV, ESV, and EF, respectively; p < 0.001). Automated 3D LV volumes and EF were highly reproducible.

CONCLUSIONS

Rapid, accurate, and reproducible EF can be obtained by RT-VTTE in NSR and AF patients by using an automated trabecular edge contouring algorithm. Furthermore, automated contour correction to detect the compacted myocardium yields accurate and reproducible 3D LV volumes.

Performance of 3-dimensional echocardiography in measuring left ventricular volumes and ejection fraction: a systematic review and meta-analysis

OBJECTIVES

The primary aim of this systematic review is to objectively evaluate the test performance characteristics of three-dimensional echocardiography (3DE) in measuring left ventricular (LV) volumes and ejection fraction (EF).

BACKGROUND

Despite its growing use in clinical laboratories, the accuracy of 3DE has not been studied on a large scale. It is unclear if this technology offers an advantage over traditional two-dimensional (2D) methods.

METHODS

We searched for studies that compared LV volumes and EF measured by 3DE and cardiac magnetic resonance (CMR) imaging. A subset of those also compared standard 2D methods with CMR. We used meta-analyses to determine the overall bias and limits of agreement of LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF measured by 3DE and 2D echocardiography (2DE).

RESULTS

Twenty-three studies (1,638 echocardiograms) were included. The pooled biases ± 2 SDs for 3DE were -19.1 ± 34.2 ml, -10.1 ± 29.7 ml, and - 0.6 ± 11.8% for EDV, ESV, and EF, respectively. Nine studies also included data from 2DE, where the pooled biases were -48.2 ± 55.9 ml, -27.7 ± 45.7 ml, and 0.1 ± 13.9% for EDV, ESV, and EF, respectively. In this subset, the difference in bias between 3DE and 2D volumes was statistically significant (p = 0.01 for both EDV and ESV). The difference in variance was statistically significant (p < 0.001) for all 3 measurements.

CONCLUSIONS

Three-dimensional echocardiography underestimates volumes and has wide limits of agreement, but compared with traditional 2D methods in these carefully performed studies, 3DE is more accurate for volumes and more precise in all 3 measurements.

Effects of Age and Gender on Left Atrial Ejection Force and Volume from Real-Time Three-Dimensional Echocardiography

Introduction: This study was carried out to (i) provide the methodology for determining left atrial (LA) volume, emptying fraction and ejection force (LAEF), from real-time 3-dimensional echocardiography (RT3DE), and (ii) evaluate the effects of age and gender on LA volume and LAEF in a wide age range of healthy participants. Materials and Methods: RT3DE was performed in 102 healthy participants (age range, 20 to 80 years). From full-volume data sets, LA endocardial borders were automatically traced and LA volumes were determined. LAEF was calculated as 1/3×mitral annular area × (blood density) × (peak velocity of A wave)2 according to Newton’s law of motion and hydrodynamics; wherein the mitral annular area (MVA) is traced using RT3DE and A is the peak Doppler-derived blood velocity at atrial systole with the sample volume placed at the mitral annulus level. Results: ANOVA analysis revealed that LA volume indices were significantly correlated with age (r = 0.366, P <0.0001 for maximal volume index and r = 0.288, P <0.005 for minimal volume index). LAEF was also significantly positively correlated with age (r = 0.49, P <0.0001). The LA emptying fraction was maintained across ages. LA volume indices and LAEF did not differ significantly with gender. Conclusion: Our data can be used as normal reference values for LA volumes and LAEF. We have demonstrated that age is positively related to LA volume indices and LAEF, which suggests that age-dependent cut-off values should be considered in those with heart disease. Key words: Age, LA Ejection Force, RT3DE, Volume

Novel echocardiographic techniques to assess left atrial size, anatomy and function

Three-dimensional echocardiography (3DE) and speckle tracking echocardiography (STE) have recently applied as imaging techniques to accurately evaluate left atrial (LA) size, anatomy and function. 3DE and off-line quantification softwares, have allowed, in comparison to magnetic resonance imaging, the most time-efficient and accurate method of LA volume quantification. STE provides a non-Doppler, angle-independent and objective quantification of LA myocardial deformation. Data regarding feasibility, accuracy and clinical applications of LA analysis by 3DE and STE are rapidly gathering. This review describes the fundamental concepts of LA 3DE and STE, illustrates how to obtain respective measurements and discuss their recognized and emerging clinical applications.

Quantitative analysis of left atrial function in asymptomatic patients with b-thalassemia major using real-time three-dimensional echocardiography

Background

There is strong evidence that left atrial (LA) size is a prognostic marker in a variety of heart diseases. Recently, real-time three-dimensional echocardiography (RT3DE) has been reported as a useful tool for studying the phasic changes of the left atrial volumes. The aim of this study was to investigate the performance of the left atrium in beta-thalassemic patients with preserved left ventricular ejection fraction (EF) and no iron overload, using RT3DE.

Methods

Twenty-eight asymptomatic b-thalassemic patients (32.2 ± 4.3 years old, 17 men) who were on iron chelating therapy, as well as 20 age- and sex-matched healthy controls underwent transthoracic RT3DE. The patient group had normal echocardiographic systolic and diastolic indices, while there was no myocardial iron disposition according to MRI. Apical full volume data sets were obtained and LA volumes were measured at 3 time points of the cardiac cycle: (1) maximum volume (LAmax) at end-systole, just before mitral valve opening; (2) minimum volume (LAmin) at end-diastole, just before mitral valve closure; and (3) volume before atrial active contraction (LApreA) obtained from the last frame before mitral valve reopening or at time of the P wave on the surface electrocardiogram. From the derived values, left atrial active and passive emptying volumes, as well as the respective emptying fractions were calculated.

Results

Left ventricular EF (59.2 ± 2.5% patients vs. 60.1 ± 2.1% controls), E/A, E/E' were similar between the two groups. Differences in the LAmax, LAmin and LApreA between b-thalassemic patients and controls were non-significant, LAmax:(35.5 ± 13.4 vs 31.8 ± 9.8)cm³, LAmin:(16.0 ± 6.0 vs. 13.5 ±4.2)cm³, and LApreA:(25.4 ± 9.8 vs. 24.3 ± 7.2)cm³. However, left atrial active emptying fraction was reduced in the patient group as compared to the healthy population (34.3 ± 16.4% vs. 43.2 ± 11.4%, p < 0.05).

Conclusion

RT3DE may be a novel technique for the evaluation of LA function in asymptomatic patients with b-Thalassemia Major. Among three-dimensional volumes and indices, left atrial active emptying fraction may be an early index of LA dysfunction in the specific patient population.

Multiview fusion 3-D echocardiography: improving the information and quality of real-time 3-D echocardiography

The advent of real-time 3-D echocardiography (RT3DE) promised dynamic 3-D image acquisition with the potential of a more objective and complete functional analysis. In spite of that, 2-D echocardiography remains the backbone of echocardiography imaging in current clinical practice, with RT3DE mainly used for clinical research. The uptake of RT3DE has been slow because of missing anatomic information, limited field-of-view (FOV) and tedious analysis procedures. This paper presents multiview fusion 3D echocardiography, where multiple images with complementary information are acquired from different probe positions. These multiple images are subsequently aligned and fused together for preserving salient structures in a single, multiview fused image. A novel and simple wavelet-based fusion algorithm is proposed that exploits the low- and high-frequency separation capability of the wavelet analysis. The results obtained show that the proposed multiview fusion considerably improves the contrast (31.1%), contrast-to-noise ratio (46.7%), signal-to-noise ratio (44.7%) and anatomic features (12%) in 3-D echocardiography, and enlarges the FOV (28.2%). This indicates that multiview fusion substantially enhances the image quality and information.

Three-dimensional simultaneous strain-volume analysis describes left ventricular remodelling and its progression: a pilot study

AIMS

Three-dimensional (3D)-echocardiography speckle imaging allows the evaluation of frame-by-frame strain and volume changes simultaneously. The aim of the present investigation was to describe the strain-volume combined assessment in different patterns of cardiac remodelling.

METHODS AND RESULTS

Fifty patients received a 3D acquisition. Patients were classified as follows: healthy subjects (CNT), previous AMI, and normal ejection fraction (EF; group A); ischaemic cardiomyopathy with reduced EF (group B); hypertrophic/infiltrative cardiomyopathy (group C). Values of 3D strain were plotted vs. volume for each frame to build a strain-volume curve for each case. Peak of radial, longitudinal, and circumferential systolic strain (Rεp, Lεp, and Cεp, respectively), slopes of the curves (RεSl, LεSl, CεSl), and strain to end-diastolic volume (EDV) ratio (Rε/V, Lε/V, Cε/V) were computed for the analysis. Strain-volume curves of the CNT group were steep and clustered, whereas, due to progressive dilatation and reduction of strains, progressive flattening could be demonstrated in groups A and B. Quantitative data supported visual assessment with progressive lower slopes (P< 0.05 for RεSl, CεSl, P= 0.06 for LεSl) and significantly lower ratios (P< 0.01 for Rε/V, Lε/V, and Cε/V). Group C showed an opposite behaviour with slopes and ratios close to those of normal subjects. Correlation coefficients between EDV and slopes of the curves were significant for all the directions of strain (CεSl: r = 0.891; RєSl: r = 0.704; LєSl: r = 0.833; P< 0.0001 for all).

CONCLUSION

We measured left ventricular volumes and strain by 3D-echo and obtained strain-volume curve to evaluate their behaviour in remodelling. A distinctive and progressive pattern consistent with pathophysiology was observed. The analysis here shown could represent a new non-invasive method to assess myocardial mechanics and its relationship with volumes.

Automated analysis of three-dimensional stress echocardiography

Real-time three-dimensional (3D) ultrasound imaging has been proposed as an alternative for two-dimensional stress echocardiography for assessing myocardial dysfunction and underlying coronary artery disease. Analysis of 3D stress echocardiography is no simple task and requires considerable expertise. In this paper, we propose methods for automated analysis, which may provide a more objective and accurate diagnosis. Expert knowledge is incorporated via statistical modelling of patient data. Methods for identifying anatomical views, detecting endocardial borders, and classification of wall motion are described and shown to provide favourable results. We also present software developed especially for analysis of 3D stress echocardiography in clinical practice. Interobserver agreement in wall motion scoring is better using the dedicated software (96%) than commercially available software not dedicated for this purpose (79%). The developed tools may provide useful quantitative and objective parameters to assist the clinical expert in the diagnosis of left ventricular function.

Three-dimensional echocardiography for left ventricular quantification: fundamental validation and clinical applications

One of the earliest applications of clinical echocardiography is evaluation of left ventricular (LV) function and size. Accurate, reproducible and quantitative evaluation of LV function and size is vital for diagnosis, treatment and prediction of prognosis of heart disease. Early three-dimensional (3D) echocardiographic techniques showed better reproducibility than two-dimensional (2D) echocardiography and narrower limits of agreement for assessment of LV function and size in comparison to reference methods, mostly cardiac magnetic resonance (CMR) imaging, but acquisition methods were cumbersome and a lack of user-friendly analysis software initially precluded widespread use. Through the advent of matrix transducers enabling real-time three-dimensional echocardiography (3DE) and improvements in analysis software featuring semi-automated volumetric analysis, 3D echocardiography evolved into a simple and fast imaging modality for everyday clinical use. 3DE provides the possibility to evaluate the entire LV in three spatial dimensions during the complete cardiac cycle, offering a more accurate and complete quantitative evaluation the LV. Improved efficiency in acquisition and analysis may provide clinicians with important diagnostic information within minutes. The current article reviews the methodology and application of 3DE for quantitative evaluation of the LV, provides the scientific evidence for its current clinical use, and discusses its current limitations and potential future directions.

Assessment of left ventricular volumes and function by real time three-dimensional echocardiography in a pediatric population: a TomTec versus QLAB comparison

BACKGROUND

Three-dimensional echocardiography (3DE) allows accurate calculation of ventricular volumes despite a remaining geometric assumption on the ventricular shape. Few studies involving full volume reconstruction software have been performed on children. Our aim was to compare the left ventricular (LV) volume measurements obtained with the most used 3D analysis software in a pediatric population.

METHODS

Fifty patients (median age: 9.5 years) without cardiac disease were included in the study. 3DE was performed with the X4-2 or X7-2 matrix probe (ie33, Philips). The LV volume analysis was performed with QLAB 6.0 (semiautomated border detection) and TomTec 4D LV (primary manual tracking with semiautomated border detection).

RESULTS

TomTec analysis feasibility amounted to 94% whereas QLAB analysis feasibility only reached 80% (P = 0.037). The analysis time was shorter with QLAB than TomTec (5 ± 2 versus 6 ± 3 minutes, P < 0.05). The stroke volume, end diastolic and end systolic LV volume measurements performed on the 40 patients were strongly correlated (r > 0.97; P < 0.0001) with minimal bias. The LV ejection fraction was well correlated (r = 0.79; P < 0.0001).

CONCLUSION

3D LV volume quantification is feasible either by using manual or automated reconstruction software in a normal pediatric population. LV Measurements are well correlated. Differences in volume reconstruction algorithms provide specific software performance characteristics. TomTec is a more feasible method but requires a longer analysis time. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

The evaluation of single-view and multi-view fusion 3D echocardiography using image-driven segmentation and tracking

Real-time 3D echocardiography (RT3DE) promises a more objective and complete cardiac functional analysis by dynamic 3D image acquisition. Despite several efforts towards automation of left ventricle (LV) segmentation and tracking, these remain challenging research problems due to the poor-quality nature of acquired images usually containing missing anatomical information, speckle noise, and limited field-of-view (FOV). Recently, multi-view fusion 3D echocardiography has been introduced as acquiring multiple conventional single-view RT3DE images with small probe movements and fusing them together after alignment. This concept of multi-view fusion helps to improve image quality and anatomical information and extends the FOV. We now take this work further by comparing single-view and multi-view fused images in a systematic study. In order to better illustrate the differences, this work evaluates image quality and information content of single-view and multi-view fused images using image-driven LV endocardial segmentation and tracking. The image-driven methods were utilized to fully exploit image quality and anatomical information present in the image, thus purposely not including any high-level constraints like prior shape or motion knowledge in the analysis approaches. Experiments show that multi-view fused images are better suited for LV segmentation and tracking, while relatively more failures and errors were observed on single-view images.

Echocardiographic strain imaging and its use in the clinical setting

The use of echocardiography has grown tremendously over the past several years. It is used routinely for diagnosis, prognosis and monitoring changes of cardiac function in coronary artery disease, heart failure, pulmonary hypertension, arrhythmias, pericardial disease and valvular disease, as well as congenital conditions. In recent years, the advancing technology used to evaluate the heart by ultrasound has allowed physicians to understand the mechanics of the heart muscle and the contribution of abnormalities in myocardial movement to heart disease. This review will discuss novel echocardiographic strain imaging techniques, placing them in the context of myocardial mechanics and describing current and future applications.

Automated border detection in three-dimensional echocardiography: principles and promises

Several automated border detection approaches for three-dimensional echocardiography have been developed in recent years, allowing quantification of a range of clinically important parameters. In this review, the background and principles of these approaches and the different classes of methods are described from a practical perspective, as well as the research trends to achieve a robust method.