Test-Retest Variability of Volumetric Right Ventricular Measurements Using Real-Time Three-Dimensional Echocardiography

A closer look at right ventricular 3D volume quantification by transthoracic echocardiography and cardiac MRI

AIM

To compare right ventricular (RV) volumetry using state-of-the-art three-dimensional (3D) transthoracic echocardiography (3DE) and cardiac magnetic resonance imaging (CMR) near-simultaneously in a clinical setting.

MATERIALS AND METHODS

Forty-seven consecutive patients received comprehensive echocardiography including 3DE within 30 minutes of CMR. RV volumetry was performed offline with semi-automated 3D endocardial border tracing as well as manual delineation of the compacted myocardium in short-axis views by CMR.

RESULTS

Forty-two examinations (89%) could be analysed offline by 3D RV reconstruction. Mean RV volumes assessed by CMR and 3DE were 215±63 and 127±42 ml for end-diastole (RV-EDV), as well as 110±43 and 62±27 ml for end-systole (RV-ESV). RV-EDV, RV-ESV, and RV stroke volume measured by 3DE were significantly lower than RV volumetry by CMR. Mean bias were -88, -48, and -41 ml, respectively. Mean RV ejection fraction (-EF) showed a non-significant deviation of +2% between 3DE and CMR and the correlation coefficient was r=0.58 for RV-EF.

CONCLUSION

RV-EF can be assessed reliably using transthoracic 3DE in patients with good image quality; however, absolute RV volumes measured by 3DE show a systematic deviation to CMR volumetry that has been previously neglected and requires careful interpretation regarding anatomical cardiac imaging.

Strain Analysis of the Right Ventricle Using Two-dimensional Echocardiography

Right ventricular (RV) systolic dysfunction has been identified as an independent prognostic marker of many cardiovascular diseases. However, there are problems in measuring RV systolic function objectively and identification of RV dysfunction using conventional echocardiography. Strain echocardiography is a new imaging modality to measure myocardial deformation. It can measure intrinsic myocardial function and has been used to measure regional and global left ventricular (LV) function. Although the RV has different morphologic characteristics than the LV, strain analysis of the RV is feasible. After strain echocardiography was introduced to measure RV systolic function, it became more popular and was incorporated into recent echocardiographic guidelines. Recent studies showed that RV global longitudinal strain (RVGLS) can be used as an objective index of RV systolic function with prognostic significance. In this review, we discuss RVGLS measurement, normal reference values, and the clinical importance of RVGLS.

Long-term impacts of hemodialysis on the right ventricle: Assessment via 3-dimensional speckle-tracking echocardiography

BACKGROUND

Right ventricular (RV) dysfunction is a major cause of death in patients undergoing maintenance hemodialysis (MHD). We used 3-dimensional speckle-tracking echocardiography (3DSTE) to evaluate long-term impacts of MHD on RV function.

HYPOTHESIS

In this study, RV dysfunction in MHD patients will be revealed and studied in depth by 3DSTE.

METHODS

Echocardiography was performed on 110 consecutively enrolled individuals: 30 controls and 80 patients with MHD. Conventional echocardiographic parameters and 3DSTE parameters were obtained and compared between groups. Univariate and multivariate logistic regression analysis identified independent predictors of intradialytic hypotension (IDH).

RESULTS

Compared with the control group, RV end-diastolic volume (RVEDV) was markedly enlarged (46.1 ± 11.8 mL/m² vs 42.3 ± 8.6 mL/m² ; P = 0.047), whereas RV ejection fraction (RVEF) was significantly lower in the MHD group (50.6% ± 5.8% vs 55.2% ± 3.7%; P < 0.001). RV global, septal, and lateral wall longitudinal strains were also decreased in the MHD group (-18.2 ± 3.6 vs -22.6 ± 4.3%; -13.1 ± 3.8 vs -17.5 ± 5.5%; and -23.4 ± 4.7 vs -27.7 ± 4.0%, respectively; all P < 0.001). RVEF (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.51 to 1.01, P = 0.038) and history of diabetes (OR: 11.14, 95% CI: 1.16 to 106.71, P = 0.036) were 2 independent predictors of IDH. Ultrafiltration rate was an independent factor associated with RVEF (β = -0.01, 95% CI: -0.019 to 0.001, P = 0.039).

CONCLUSIONS

RVEF by 3DSTE could be an important predictor of IDH in MHD patients, and lower ultrafiltration rate was protective for RVEF. 3DSTE may have potential in RV evaluation and risk stratification in MHD patients.

Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good acoustic windows and the non-invasive nature of the technique. The aim of this paper is to provide a review of the optimal application of 3DE in CHD including technical considerations, image orientation, application to different lesions, procedural guidance, and functional assessment.

Accuracy and Test-Retest Reproducibility of Two-Dimensional Knowledge-Based Volumetric Reconstruction of the Right Ventricle in Pulmonary Hypertension

Background

Right heart function is the key determinant of symptoms and prognosis in pulmonary hypertension (PH), but the right ventricle has a complex geometry that is challenging to quantify by two-dimensional (2D) echocardiography. A novel 2D echocardiographic technique for right ventricular (RV) quantitation involves knowledge-based reconstruction (KBR), a hybrid of 2D echocardiography–acquired coordinates localized in three-dimensional space and connected by reference to a disease-specific RV shape library. The aim of this study was to determine the accuracy of 2D KBR against cardiac magnetic resonance imaging in PH and the test-retest reproducibility of both conventional 2D echocardiographic RV fractional area change (FAC) and 2D KBR.

Methods

Twenty-eight patients with PH underwent same-day echocardiography and cardiac magnetic resonance imaging. Two operators performed serial RV FAC and 2D KBR acquisition and postprocessing to assess inter- and intraobserver test-retest reproducibility.

Results

Bland-Altman analysis (mean bias ± 95% limits of agreement) showed good agreement for end-diastolic volume (3.5 ± 25.0 mL), end-systolic volume (0.9 ± 19.9 mL), stroke volume (2.6 ± 23.1 mL), and ejection fraction (0.4 ± 10.2%) measured by 2D KBR and cardiac magnetic resonance imaging. There were no significant interobserver or intraobserver test-retest differences for 2D KBR RV metrics, with acceptable limits of agreement (interobserver end-diastolic volume, −0.9 ± 21.8 mL; end-systolic volume, −1.3 ± 25.8 mL; stroke volume, −0.2 ± 24.2 mL; ejection fraction, 0.7 ± 14.4%). Significant test-retest variability was observed for 2D echocardiographic RV areas and FAC.

Conclusions

Two-dimensional KBR is an accurate, novel technique for RV volumetric quantification in PH, with superior test-retest reproducibility compared with conventional 2D echocardiographic RV FAC.

The role of nuclear imaging in pulmonary hypertension

Pulmonary hypertension (PH) is a disease characterized by a chronic elevation of pulmonary artery pressure from various causes. Pulmonary artery hypertension (PAH) is one of subtype which results in premature death often as a result of right ventricular (RV) dysfunction. In spite of the recent progress in novel cardiac imaging techniques and new drugs for PAH, there remain significant unresolved issues including a need for earlier diagnosis, refinement of risk stratification, and monitoring the effects of treatment. Cardiac and pulmonary imaging with transthoracic echocardiography (TTE) with Doppler, magnetic resonance imaging (MRI), and computed tomography (CT) are done routinely in many clinical centers. However, routine and emerging nuclear techniques may have a pivotal role of assessment of the patient with PH, and is currently the subject of significant research. Potential Roles for Nuclear Imaging in the Evaluation of the PH Patient: (1) Evaluation of cardiac structure and function (RNA) (non-nuclear techniques would include TTE, CT, and MRI). (2) Functional imaging. This includes the use of ventilation-perfusion scintigraphy (V/Q scan) to diagnose chronic thromboembolic pulmonary hypertension (CTEPH), 123l-metaiodobenzylguanidine (MIBG) imaging to evaluate the cardiac sympathetic nervous system (non-nuclear techniques include invasive right heart catheterization and TTE). (3) Measurement of RV perfusion (with gated SPECT studies). (4) Evaluation of cardiac and pulmonary metabolism (PET scans). This review article will summarize the pathophysiology, classification, natural history, and diagnostic approach of PH. Current and emerging nuclear techniques will be discussed under the four themes of evaluation of structure, functional imaging, flow, and metabolism. These will be compared to current and emerging nuclear and non-nuclear diagnostic tests in the evaluation and management of patients with PH. We will also discuss research applications exploring new insights into flow and metabolism in the right heart and lung and the application of new radioligands.

Assessment of right ventricular volumes and ejection fraction by echocardiography: from geometric approximations to realistic shapes

Right ventricular volumes and ejection fraction are challenging to assess by echocardiography, but are well established as functional and prognostic parameters. Three-dimensional (3D) echocardiography has become widespread and relatively easy to use, making calculation of these parameters feasible in the large majority of patients. We review past attempts to estimate right ventricular volumes, current strengths and weaknesses of 3D echocardiography for this task, and compare with corresponding data from magnetic resonance imaging.

Accuracy and reproducibility of right ventricular quantification in patients with pressure and volume overload using single-beat three-dimensional echocardiography

Background

The right ventricle is a complex structure that is challenging to quantify by two-dimensional (2D) echocardiography. Unlike disk summation three-dimensional (3D) echocardiography (3DE), single-beat 3DE can acquire large volumes at high volume rates in one cardiac cycle, avoiding stitching artifacts or long breath-holds. The aim of this study was to assess the accuracy and test-retest reproducibility of single-beat 3DE for quantifying right ventricular (RV) volumes in adult populations of acquired RV pressure or volume overload, namely, pulmonary hypertension (PH) and carcinoid heart disease, respectively. Three-dimensional and 2D echocardiographic indices were also compared for identifying RV dysfunction in PH.

Methods

A prospective cross-sectional study was performed in 100 individuals who underwent 2D echocardiography, 3DE, and cardiac magnetic resonance imaging: 49 patients with PH, 20 with carcinoid heart disease, 11 with metastatic carcinoid tumors without cardiac involvement, and 20 healthy volunteers. Two operators performed test-retest acquisition and postprocessing for inter- and intraobserver reproducibility in 20 subjects.

Results:

RV single-beat 3DE was attainable in 96% of cases, with mean volume rates of 32 to 45 volumes/sec. Bland-Altman analysis of all subjects (presented as mean bias ± 95% limits of agreement) revealed good agreement for end-diastolic volume (−2.3 ± 27.4 mL) and end-systolic volume (5.2 ± 19.0 mL) measured by 3DE and cardiac magnetic resonance imaging, with a tendency to underestimate stroke volume (−7.5 ± 23.6 mL) and ejection fraction (−4.6 ± 13.8%) by 3DE. Subgroup analysis demonstrated a greater bias for volumetric underestimation, particularly in healthy volunteers (end-diastolic volume, −11.9 ± 18.0 mL; stroke volume, −11.2 ± 20.2 mL). Receiver operating characteristic curve analysis showed that 3DE-derived ejection fraction was significantly superior to 2D echocardiographic parameters for identifying RV dysfunction in PH (sensitivity, 94%; specificity, 88%; area under the curve, 0.95; P = .031). There was significant interobserver test-retest bias for RV volume underestimation (end-diastolic volume, −12.5 ± 28.1 mL; stroke volume, −10.6 ± 23.2 mL).

Conclusions

Single-beat 3DE is feasible and clinically applicable for volumetric quantification in acquired RV pressure or volume overload. It has improved limits of agreement compared with previous disk summation 3D echocardiographic studies and has incremental value over standard 2D echocardiographic measures for identifying RV dysfunction. Despite the ability to obtain and postprocess a full-volume 3D echocardiographic RV data set, the quality of the raw data did influence the accuracy of the data obtained. The technique performs better with dilated rather than nondilated RV cavities, with a learning curve that might affect the test-retest reproducibility for serial RV studies.

Reproducibility and correlations of right ventricular end-diastolic volume index measured by real-time three-dimensional echocardiography

BACKGROUND

To correlate right ventricular volumes measured by real-time three-dimensional echocardiography (RT3DE) with left ventricular volume indices in patients with or without left-sided heart diseases.

METHODS

For this retrospective, we reviewed 806 consecutive RT3DE examinations with quantitative evaluation of both the left and the right (RV) ventricle. We excluded cases of disease or surgery that would directly affect the size of the RV (eg, intracardiac shunt, significant tricuspid, or pulmonic regurgitation) as well as poor sonographic image quality, leaving a total of 701 studies for analysis. RV volumetric quantification was performed using dedicated software.

RESULTS

Linear regression analysis showed that left ventricular stroke volume index significantly correlated with RV end-diastolic volume index (RVEDVI) (r = 0.78, p < 0.0001). Overall, 4% (28 of 701) of the patients had RVEDVI lower than 50 ml/m(2) , and 12% (84 of 701) had RVEDVI greater than 100 ml/m(2) . Intraclass correlation coefficient ranged from 0.91 to 0.99 for intraobserver and 0.85 to 0.98 for interobserver reproducibility.

CONCLUSIONS

RT3DE was feasible and reproducible for quantifying RV volume. In patients without known primary RV pathology, RV volume strongly correlated with left ventricular stroke volume.

Three-dimensional transesophageal echocardiography for perioperative right ventricular assessment

BACKGROUND

In high-risk cardiac procedures, dynamic analysis of right ventricular (RV) performance is desirable, but the geometric complexity of the RV limits the applicability of current two-dimensional echocardiographic imaging techniques. This study aimed to evaluate the utility of three-dimensional transesophageal echocardiography (TEE) for the perioperative assessment of RV function and dimensions.

METHODS

Patients undergoing cardiac surgical procedures with complete TEE examinations were identified and reviewed according to current guidelines to exclude patients with significant coexisting valvular regurgitation. Full-volume, three-dimensional datasets were analyzed by two independent investigators using stand-alone software, and left ventricular and RV dimensions were recorded.

RESULTS

Datasets from 50 patients undergoing cardiac surgical procedures were evaluated for this study. The mean RV volume was 111.7 mL (range, 37.5 to 349.7 mL) at end diastole and 67.6 mL (range, 25.5 to 274.4 mL) at end systole. Intraobserver reliability was 0.93 and 0.90 for end diastolic and 0.77 and 0.87 for end systolic volumes. The interobserver reliability for RV volumes was 0.83 at end diastole and 0.86 at end systole. The mean stroke volume was 43.6 mL (range, 12 to 111.2 mL) for the RV and 49.1 mL (range, 19.9 to 102.8 mL) for the left ventricle; the correlation coefficient between the two was 0.85.

CONCLUSIONS

Three-dimensional TEE volumetric measurements were reproducible across a wide range of RV dimensions. As postulated by the continuity principle, stroke volume measurements between both ventricles correlated well, supporting the validity of this approach. Therefore, our work provides preliminary evidence that three-dimensional TEE offers reproducible information about RV function and size in the dynamic and complex perioperative setting of cardiac surgical procedures.

Imaging the right heart: the use of integrated multimodality imaging

During recent years, right ventricular (RV) structure and function have been found to be an important determinant of outcome in different cardiovascular and also pulmonary diseases. Currently, echocardiography and cardiac magnetic resonance (CMR) imaging are the two imaging modalities most commonly used to visualize the RV. Most structural abnormalities of the RV can be reliably described by echocardiography but due its complex geometrical shape, echocardiographic assessment of RV function is more challenging. Newer promising echocardiographic techniques are emerging but lack of validation and limited normal reference data influence their routine clinical application. Cardiac magnetic resonance is generally considered the clinical reference technique due to its unlimited imaging planes, superior image resolution, and three-dimensional volumetric rendering. The accuracy and reliability of CMR measurements make it the ideal tool for serial examinations of RV function. Multidetector computed tomography (MDCT) plays an important role in the diagnosis of pulmonary emboli but can also be used for assessing RV ischaemic disease or as an alternative for CMR if contra-indicated. Radionuclide techniques have become more obsolete in the current era. The different imaging modalities should be considered complimentary and each plays a role for different indications.

[State of the art: new developments in cardiac imaging]

Cardiac imaging continues to reveal new anatomical and functional insights into heart disease. In echocardiography, both transesophageal and transthoracic three-dimensional imaging have been fully developed and optimized, and the value of the techniques that have increased our understanding of cardiac mechanics and ventricular function is well established. At the same time, the healthcare industry has released new devices onto the market which, although they are easier to use, have limitations that restrict their use for routine assessment. Tomography's diagnostic and prognostic value in coronary artery disease continues to increase while radiation exposure becomes progressively lower. With cardiac magnetic resonance imaging, myocardial injury and recovery in ischemic heart disease and following acute coronary syndrome can be monitored in exquisite detail. The emergence of new combined tomographic and gamma camera techniques, exclusively developed for nuclear cardiology, have improved the quality of investigations and reduced radiation exposure. The hybrid or fusion images produced by combining different techniques, such as nuclear cardiology techniques and tomography, promise an exciting future.

Non-Invasive Imaging for Congenital Heart Disease: Recent Innovations in Transthoracic Echocardiography

Transthoracic echocardiography (TTE) is an important tool for diagnosis and follow-up of patients with congenital heart disease (CHD). Appropriate use of TTE can reduce the need for more invasive and complex modalities, such as cardiac catheterization and cardiac magnetic resonance imaging. New echocardiographic techniques have emerged for the assessment of ventricular systolic and diastolic function: Tissue Doppler imaging, tissue tracking, strain and strain rate imaging, vector velocity imaging (VVI), myocardial performance index, myocardial acceleration during isovolumic contraction (IVA), the ratio of systolic to diastolic duration (S/D ratio), and other measurements of systolic right ventricular (RV) function like tricuspid annular plane systolic excursion (TAPSE). These modalities may become valuable indicators of ventricular performance, compliance and disease progression, with the caveat of preload-dependency of the variables measured. In addition, three-dimensional (3D) echocardiography for the assessment of cardiac anatomy, valvular function, device position, ventricular volumes and ejection fraction is integrated into routine clinical care. In this review, we discuss the potential use and limitations of these new echocardiographic techniques in patients with CHD. A particular focus is on the echocardiographic assessment of right ventricular (RV) function by means of tissue Doppler imaging, tissue tracking, and three-dimensional imaging, in conditions associated with increased right ventricular volume or pressure load.