Manual correction of semi-automatic three-dimensional echocardiography is needed for right ventricular assessment in adults; validation with cardiac magnetic resonance

Evolving Role of Three-Dimensional Echocardiography for Right Ventricular Volume Analysis in Pediatric Heart Disease: Literature Review and Clinical Applications

Accurate knowledge of right ventricular (RV) volumes and ejection fraction is fundamental to providing optimal care for pediatric patients with congenital and acquired heart disease, as well as pulmonary hypertension. Traditionally, these volumes have been measured using cardiac magnetic resonance because of its accuracy, reproducibility, and freedom from geometric assumptions. More recently, an increasing number of studies have described the measurement of RV volumes using three-dimensional (3D) echocardiography. In addition, volumes by 3D echocardiography have also been used for outcome research studies in congenital heart surgery. Importantly, 3D echocardiographic acquisitions can be obtained over a small number of cardiac cycles, do not require general anesthesia, and are less costly than CMR. The ease and safety of the 3D echocardiographic acquisitions allow serial studies in the same patient. Moreover, the studies can be performed in various locations, including the intensive care unit, catheterization laboratory, and general clinic. Because of these advantages, 3D echocardiography is ideal for serial evaluation of the same patient. Despite these potential advantages, 3D echocardiography has not become a standard practice in children with congenital and acquired heart conditions. In this report, the authors review the literature on the feasibility, reproducibility, and accuracy of 3D echocardiography in pediatric patients. In addition, the authors investigate the advantages and limitations of 3D echocardiography in RV quantification and offer a pathway for its potential to become a standard practice in the assessment, planning, and follow-up of congenital and acquired heart disease.

Three-dimensional echocardiographic evaluation of longitudinal and non-longitudinal components of right ventricular contraction: results from the World Alliance of Societies of Echocardiography study

AIMS

Right ventricular (RV) functional assessment is mainly limited to its longitudinal contraction. Dedicated three-dimensional echocardiography (3DE) software enabled the separate assessment of the non-longitudinal components of RV ejection fraction (EF). The aims of this study were (i) to establish normal values for RV 3D-derived longitudinal, radial, and anteroposterior EF (LEF, REF, and AEF, respectively) and their relative contributions to global RVEF, (ii) to calculate 3D RV strain normal values, and (iii) to determine sex-, age-, and race-related differences in these parameters in a large group of normal subjects (WASE study).

METHODS AND RESULTS

3DE RV wide-angle datasets from 1043 prospectively enrolled healthy adult subjects were analysed to generate a 3D mesh model of the RV cavity (TomTec). Dedicated software (ReVISION) was used to analyse RV motion along the three main anatomical planes. The EF values corresponding to each plane were identified as LEF, REF, and AEF. Relative contributions were determined by dividing each EF component by the global RVEF. RV strain analysis included longitudinal, circumferential, and global area strains (GLS, GCS, and GAS, respectively). Results were categorized by sex, age (18-40, 41-65, and >65 years), and race. Absolute REF, AEF, LEF, and global RVEF were higher in women than in men (P < 0.001). With aging, both sexes exhibited a decline in all components of longitudinal shortening (P < 0.001), which was partially compensated in elderly women by an increase in radial contraction. Black subjects showed lower RVEF and GAS values compared with white and Asian subjects of the same sex (P < 0.001), and black men showed significantly higher RV radial but lower longitudinal contributions to global RVEF compared with Asian and white men.

CONCLUSION

3DE evaluation of the non-longitudinal components of RV contraction provides additional information regarding RV physiology, including sex-, age-, and race-related differences in RV contraction patterns that may prove useful in disease states involving the right ventricle.

High-echoic line tracing of transthoracic echocardiography accurately assesses right ventricular enlargement in adult patients with atrial septal defect

Accurate measurement of right ventricular (RV) size using transthoracic echocardiography (TTE) is important for evaluating the severity of congenital heart diseases. The RV end-diastolic area index (RVEDAi) determined using TTE is used to assess RV dilatation; however, the tracing line of the RVEDAi has not been clearly defined by the guidelines. This study aimed to determine the exact tracing method for RVEDAi using TTE. We retrospectively studied 107 patients with atrial septal defects who underwent cardiac magnetic resonance imaging (CMR) and TTE. We measured the RVEDAi according to isoechoic and high-echoic lines, and compared it with the RVEDAi measured using CMR. The isoechoic line was defined as the isoechoic endocardial border of the RV free wall, whereas the high-echoic line was defined as the high-echoic endocardial border of the RV free wall more outside than the isoechoic line. RVEDAi measured using high-echoic line (high-RVEDAi) was more accurately related to RVEDAi measured using CMR than that measured using isoechoic line (iso-RVEDAi). The difference in the high-RVEDAi was 0.3 cm²/m², and the limit of agreement (LOA) was - 3.7 to 4.3 cm²/m². With regard to inter-observer variability, high-RVEDAi was superior to iso-RVEDAi. High-RVEDAi had greater agreement with CMR-RVEDAi than with iso-RVEDAi. High-RVEDAi can become the standard measurement of RV size using two-dimensional TTE.

Three-Dimensional Echocardiography Assessment of Right Ventricular Volumes and Function: Technological Perspective and Clinical Application

Right ventricular (RV) function has important prognostic value in a variety of cardiovascular diseases. Due to complex anatomy and mode of contractility, conventional two-dimensional echocardiography does not provide sufficient and accurate RV function assessment. Currently, three-dimensional echocardiography (3DE) allows for an excellent and reproducible assessment of RV function owing to overcoming these limitations of traditional echocardiography. This review focused on 3DE and discussed the following points: (i) acquisition of RV dataset for 3DE images, (ii) reliability, feasibility, and reproducibility of RV volumes and function measured by 3DE with different modalities, (iii) the clinical application of 3DE for RV function quantification.

The Usefulness of 4D Echocardiographic Modality for Assessing RV Affection in Uncontrolled Hypertensive Patients

BACKGROUND

In many cardiovascular disorders, the contractile performance of the right ventricle (RV) is the primary determinant of prognosis. For evaluating RV volumes and function, 4 dimensional (4D)-echocardiography has become common. This research used 2D and 4D modalities to assess RV contractile performance in hypertensive patients.

METHODS

A total of 150 patients with essential hypertension were enrolled in this study, along with 75 age and sex-matched volunteers. Clinical evaluation and echocardiographic examination (including M-mode, tissue Doppler imaging, and 2D speckle tracking) were conducted on all participants. RV volumes, 4D-ejection fraction (EF), 4D-fractional area change (FAC), 4D-tricuspid annular plane systolic excursion (TAPSE), 4D-septal and free wall (FW) strain were all measured using 4D-echocardiography.

RESULTS

Hypertensive patients showed 2D-RV systolic and diastolic dysfunction (including TAPSE, 2D-right ventricular global longitudinal strain, RV-myocardial performance index and average E/EaRV) and 4D-RV impairment (including right ventricular EF, FAC, RV strain and TAPSE, right ventricular end-diastolic volume and right ventricular end-systolic volume) compared to the control group. We verified the prevalence of RV systolic dysfunction in hypertension patients using the following parameters: 1) 15% of them had 2D-TAPSE < 17 mm vs. 40% by 4D-TAPSE; 2) 25% of them had 2D-GLS < 19% vs. 42% by 4D-septal strain and 35% by 4D FW strain; 3) 35% of hypertensive patients had 4D-EF < 45%; and finally; 4) 25% of hypertensive patients had 2D-FAC < 35% compared to 45% by 4D-FAC.

CONCLUSIONS

The incidence of RV involvement was greater in 4D than in 2D-modality trans-thoracic echocardiography. We speculated that 4D-echocardiography with 4D-strain imaging would be more beneficial for examining RV morphology and function in hypertensive patients than 2D-echocardiography, since 4D-echocardiography could estimate RV volumes and function without making geometric assumptions.

Feasibility, Reproducibility and Validation of Right Ventricular Volume and Function Assessment Using Three-Dimensional Echocardiography

Three-dimensional echocardiography (3DE) is advised for right ventricular (RV) assessment. Data regarding the optimal acquisition settings and optimization are still scarce. We aimed to evaluate the feasibility, reproducibility and validation of 3DE for RV volume and function assessment, using cardiac magnetic resonance (CMR) as gold standard. Thirty healthy volunteers and 36 consecutive patients were prospectively included. CMR was performed in the latter. Standard apical four-chamber view (A4CV), focused A4CV and modified A4CV were used for 3DE RV acquisition. Feasibility (and the effect of changes in settings) was evaluated. Intra and interobserver analyses were performed by three observers (expert vs. novice). RV parameters by echocardiography were compared to CMR. Feasibility of acquisition was 16.7% for A4CV, 80.0% for focused A4CV and 16.7% for modified A4CV. Changes in settings had no significant influence on feasibility and further analysis. Intraobserver variability was good in both expert and novice, interobserver variability was good between experienced observers. Compared to CMR, 3DE volumes were significantly lower with fair to moderate correlation (EDV: 91.1 ± 24.4 mL vs. 144.3 ± 43.0 mL (p < 0.001), r = 0.653 and ESV: 48.1 ± 16.4 mL vs. 60.4 ± 21.2 mL (p < 0.001), r = 0.530, by multi-beat 3DE and CMR respectively). These findings suggest that standardization is needed in order to implement this technique in clinical practice, thus further studies are required.

Two methods for modifed Doo-Sabin modeling of nonsmooth surfaces-applied to right ventricle modeling

Purpose: In recent years, there has been increased clinical interest in the right ventricle (RV) of the heart. RV dysfunction is an important prognostic marker for several cardiac diseases. Accurate modeling of the RV shape is important for estimating the performance. We have created computationally effective models that allow for accurate estimation of the RV shape. Approach: Previous approaches to cardiac shape modeling, including modeling the RV geometry, has used Doo-Sabin surfaces. Doo-Sabin surfaces allow effective computation and adapt to smooth, organic surfaces. However, they struggle with modeling sharp corners or ridges without many control nodes. We modified the Doo-Sabin surface to allow for sharpness using weighting of vertices and edges instead. This was done in two different ways. For validation, we compared the standard Doo-Sabin versus the sharp Doo-Sabin models in modeling the RV shape of 16 cardiac ultrasound images, against a ground truth manually drawn by a cardiologist. A Kalman filter fitted the models to the ultrasound images, and the difference between the volume of the model and the ground truth was measured. Results: The two modified Doo-Sabin models both outperformed the standard Doo-Sabin model in modeling the RV. On average, the regular Doo-Sabin had an 8-ml error in volume, whereas the sharp models had 7- and 6-ml error, respectively. Conclusions: Compared with the standard Doo-Sabin, the modified Doo-Sabin models can adapt to a larger variety of surfaces while still being compact models. They were more accurate on modeling the RV shape and could have uses elsewhere.

Accuracy and sensitivity of three-dimensional echocardiography to detect changes in right ventricular volumes: comparison study with cardiac magnetic resonance

We aimed to investigate the ability of three-dimensional transthoracic echocardiography (3DE) to detect changes in RV volumes compared to cardiac magnetic resonance (CMR). Eighty-five subjects including 45 with no known cardiac disease and 40 patients with a variety of cardiac diseases were included. Two- and three-dimensional echocardiography as well as CMR of the RV was performed before and after infusion of on average two litres of saline. Examinations were analysed with estimation of RV dimensions, volumes and ejection fraction (RVEF). Intra- and inter-examiner variability was evaluated in 25 patients randomly selected from the cohort. Three-dimensional echocardiography underestimated volumes and RVEF compared to CMR with mean differences and 95% limits of agreement of 110.3 ± 59 mL for RV end-diastolic volume (RVEDV), 43.3 ± 32 mL for RV end-systolic volume (RVESV) and 3.5 ± 10.7% for RVEF. CMR was more reproducible than 3DE, with intra-observer coefficient of variation (CV) of 4% vs. 14.2% for RVEDV, 9.7% vs. 16.7% for RVESV and 6.3% vs. 8.6% for RVEF. The RVEDV, RVESV and RV stroke volume (RVSV) by CMR significantly increased after saline infusion by 15.3 ± 16.2 mL, 3.5 ± 14.2 mL and 11.8 ± 12.6 mL, respectively, as well as RVEF by 1.5 ± 4.6% (p < 0.05). However, 3DE was not able to detect any of these changes in RV volumes (p ≥ 0.05). Compared to CMR imaging of the RV, three-dimensional echocardiography appears unable and unreliable in detecting RV volume changes of less than 15%, highlighting the need for cautious utility of 3DE in these circumstances.

Right Ventricular Systolic Function After the Cone Procedure for Ebstein's Anomaly: Comparison Between Echocardiography and Cardiac Magnetic Resonance

Although the Cone procedure has improved outcomes for patients with Ebstein´s anomaly (EA), neither RV systolic function recovery in long-term follow-up nor the best echocardiographic parameters to assess RV function are well established. Thus, we evaluated RV performance after the Cone procedure comparing two-dimensional (2DEcho) and three-dimensional (3DEcho) echocardiography to cardiac magnetic resonance (CMR). We assessed 27 EA patients after the Cone procedure (53% female, median age of 20 years at the procedure, median post-operative follow-up duration of 8 years). Echocardiography was performed 4 h apart from the CMR. RV global longitudinal strain (GLS), fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index and tissue Doppler S' velocity were assessed using 2DEcho, whereas 3DEcho was used to evaluate RV volumes and ejection fraction (RVEF). Echocardiographic variables were compared to CMR-RVEF. All patients were in the NYHA functional class I. Median TAPSE was 15.9 mm, FAC 30.2%, and RV-GLS -15%; median RVEF by 3DEcho was 31.9% and 43% by CMR. Among 2DEcho parameters, RV-GLS and FAC had a substantial correlation with CMR-RVEF (r =  - 0.63 and r = 0.55, respectively); from 3DEcho, the indexed RV volumes and RVEF were closely correlated with CMR (RV-EDVi, r = 0.60, RV-ESVi, r = 0.72; and RVEF r = 0.60). RV systolic function is impaired years after the Cone procedure, despite a good clinical status. FAC and RV-GLS are useful 2DEcho tools to assess RV function in these patients; however, 3DEcho measurements appear to provide a better RV assessment.

Impact of Right Ventricular Dilatation in Patients with Atrial Septal Defect

Objective

The aim of this study was to examine the relationship between right ventricular (RV) volume and exercise capacity in adult patients with atrial septal defect (ASD) and to determine the degree of RV dilatation for transcatheter ASD closure.

Background

RV dilatation is an indication of transcatheter ASD closure; however, few studies have reported the clinical significance of RV dilatation.

Methods

We enrolled 82 consecutive patients (mean age, 49 ± 18 years; female, 68%) who underwent cardiac magnetic resonance imaging and symptom-limited cardiopulmonary exercise test before ASD closure. The relationship between RV volume and peak oxygen uptake (VO₂) was evaluated.

Results

The mean RV end-diastolic volume index was 108 ± 27 ml/m² (range, 46 to 180 ml/m²). The mean peak VO₂ was 24 ± 7 ml/min/kg (range, 14 to 48 ml/min/kg), and the mean predicted peak VO₂ was 90 ± 23%. There were significant negative relationships of RV end-diastolic volume index with peak VO₂ (r = -0.28, p < 0.01) and predicted peak VO₂ (r = -0.29, p < 0.01). The cutoff value of RV end-diastolic volume index <80% of predicted peak VO₂ was 120 ml/m², with the sensitivity of 49% and the specificity of 89%.

Conclusions

There was a relationship between RV dilatation and exercise capacity in adult patients with ASD. RV end-diastolic volume index ≥120 ml/m² was related to the reduction in peak VO₂. This criterion of RV dilatation may be valuable for the indication of transcatheter ASD closure.

Right ventricular three-dimensional echocardiography: the current status and future perspectives

This review focused on right ventricular (RV) three-dimensional echocardiography (3DE) and discussed the following agenda. First, we summarized the clinical RV anatomy and function-related RV3DE use followed by the explanations about 3DSTE image acquisition, including pitfall. Next, we reviewed the reliability and feasibility of RV volume and RV ejection fraction measurements during the last decade. Besides, we described the techniques that might overcome the dropout images at RV anterior and out tract including the current limitations. Finally, speckle tracking echocardiography by RV3DE and novel RV shape assessment were reviewed. This review will help you get comprehensive information on the current status and future perspectives of RV3DE.

Echocardiographic assessment of the right heart in adults: a practical guideline from the British Society of Echocardiography

The structure and function of the right side of the heart is influenced by a wide range of physiological and pathological conditions. Quantification of right heart parameters is important in a variety of clinical scenarios including diagnosis, prognostication, and monitoring response to therapy. Although echocardiography remains the first-line imaging investigation for right heart assessment, published guidance is relatively sparse in comparison to that for the left ventricle. This guideline document from the British Society of Echocardiography describes the principles and practical aspects of right heart assessment by echocardiography, including quantification of chamber dimensions and function, as well as assessment of valvular function. While cut-off values for normality are included, a disease-oriented approach is advocated due to the considerable heterogeneity of structural and functional changes seen across the spectrum of diseases affecting the right heart. The complex anatomy of the right ventricle requires special considerations and echocardiographic techniques, which are set out in this document. The clinical relevance of right ventricular diastolic function is introduced, with practical guidance for its assessment. Finally, the relatively novel techniques of three-dimensional right ventricular echocardiography and right ventricular speckle tracking imaging are described. Despite these techniques holding considerable promise, issues relating to reproducibility and inter-vendor variation have limited their clinical utility to date.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Transcatheter closure of atrial septal defect in adults: time-course of atrial and ventricular remodeling and effects on exercise capacity

Investigate ventricular and atrial remodeling following atrial septal defect (ASD) closure and examine if pulmonary-to-systemic flow ratio (QP/QS) and right ventricular (RV) volume predict improvement, determined as percentage of predicted oxygen uptake (VO₂%). Long-term cardiovascular magnetic resonance (CMR) data on atrial and ventricular remodeling after ASD-closure is limited and treatment effect on exercise capacity is debated. Sixteen patients undergoing transcatheter ASD closure and 16 age and sexmatched controls were studied. CMR was performed before treatment, the day after and 3 and 12 months later. Exercise test with gas analysis was performed before and 12 months after treatment. QP/QS decreased from 2.1 ± 0.5 to 1.4 ± 0.3 at day 1 and 1.1 ± 0.1 at 3 and 12 months. Left ventricular (LV) volumes increased and normalized on day 1 whereas left atrial volumes were unchanged. RV and right atrial volumes decreased the first 3 months. LV and RV volumes had not equalized at 12 months (RV/LV ratio 1.2 ± 0.1, P < 0.01) and RV ejection fraction remained decreased compared to controls. Improvement of VO₂% after ASD closure (P < 0.01) was inversely related to QP/QS at rest (r = - 0.56, P < 0.05) but unrelated to RV end-diastolic volume (P = 0.16). Following transcatheter ASD closure, LV adaptation is rapid and RV adaptation is prolonged, with decreased systolic RV function. Patients with smaller shunts had larger improvement in VO₂% suggesting patients with defects of borderline hemodynamic significance might benefit from closure. This may be due to impaired LV diastolic function influencing shunt size and exercise capacity following ASD closure.

Semiautomated biventricular segmentation in three-dimensional echocardiography by coupled deformable surfaces

With the advancement of three-dimensional (3-D) real-time echocardiography in recent years, automatic creation of patient specific geometric models is becoming feasible and important in clinical decision making. However, the vast majority of echocardiographic segmentation methods presented in the literature focus on the left ventricle (LV) endocardial border, leaving segmentation of the right ventricle (RV) a largely unexplored problem, despite the increasing recognition of the RV's role in cardiovascular disease. We present a method for coupled segmentation of the endo- and epicardial borders of both the LV and RV in 3-D ultrasound images. To solve the segmentation problem, we propose an extension of a successful state-estimation segmentation framework with a geometrical representation of coupled surfaces, as well as the introduction of myocardial incompressibility to regularize the segmentation. The method was validated against manual measurements and segmentations in images of 16 patients. Mean absolute distances of [Formula: see text], [Formula: see text], and [Formula: see text] between the proposed and reference segmentations were observed for the LV endocardium, RV endocardium, and LV epicardium surfaces, respectively. The method was computationally efficient, with a computation time of [Formula: see text].

Clinical study of right ventricular longitudinal strain for assessing right ventricular dysfunction and hemodynamics in pulmonary hypertension

This study aimed to appraise the application of right ventricular longitudinal strain for assessing right ventricular dysfunction and severe hemodynamic changes in pulmonary hypertension. The study included 53 patients clinically diagnosed with PH. Tissue Doppler-derived tricuspid lateral annular systolic velocity (s'), early diastolic peak velocity (e'), late diastolic peak velocity (a'), tricuspid annular plane systolic excursion (TAPSE), RV index of myocardial performance (RIMP), and right ventricular fractional area change (FAC) were determined. The STI parameter was RV free wall longitudinal peak systolic strain (RV LPSS). The patients were assigned into two groups based on a RV LPSS value of - 19%.RV LPSS, s', TAPSE, RIMP, FAC, a' and e'/a' showed significant differences. PH patients with an RV LPSS≥ -19% exhibited a lower RV function (P < 0.05). RV LPSS was negatively correlated with TAPSE (r = -0.326, P < 0.05) and FAC (r = -0.495, P < 0.001) and positively correlated with RIMP (r = 0.508, P < 0.001). The optimal cut-off value of RV LPSS to reveal an mPAP ≥ 45 mmHg defined based on the receiver operating characteristic curve analysis was - 19.26% with a sensitivity of 83.9% and a specificity of 73.4%.Distinguishing the degree of RV dysfunction by 2D-STI may help physicians to determine the state of cardiac function and degree of PH in patients and offer a basis for subsequent clinical diagnosis and therapy. Our study demonstrates the superiority of RV LPSS for uncovering severe PH over the traditional echocardiographic parameters.

Automated Segmentation of the Right Ventricle in 3D Echocardiography: A Kalman Filter State Estimation Approach

As the right ventricle's (RV) role in cardiovascular diseases is being more widely recognized, interest in RV imaging, function and quantification is growing. However, there are currently few RV quantification methods for 3D echocardiography presented in the literature or commercially available. In this paper we propose an automated RV segmentation method for 3D echocardiographic images. We represent the RV geometry by a Doo-Sabin subdivision surface with deformation modes derived from a training set of manual segmentations. The segmentation is then represented as a state estimation problem and solved with an extended Kalman filter by combining the RV geometry with a motion model and edge detection. Validation was performed by comparing surface-surface distances, volumes and ejection fractions in 17 patients with aortic insufficiency between the proposed method, magnetic resonance imaging (MRI), and a manual echocardiographic reference. The algorithm was efficient with a mean computation time of 2.0 s. The mean absolute distances between the proposed and manual segmentations were 3.6 ± 0.7 mm. Good agreements of end diastolic volume, end systolic volume and ejection fraction with respect to MRI ( -26±24 mL , -16±26 mL and 0 ± 10%, respectively) and a manual echocardiographic reference (7 ± 30 mL, 13 ± 17 mL and -5±7% , respectively) were observed.

Real-Time Three-Dimensional Echocardiography to Assess Right Ventricle Function in Patients with Pulmonary Hypertension

Background

The convenience and availability of real-time three-dimensional echocardiography (RT3DE) makes it an attractive candidate for assessing right ventricle function. However, the viability of RT3DE is not conclusive.

Aim of Study

This study aims to evaluate RT3DE relative to cardiac magnetic resonance and 2-dimensional echocardiography (2DE) for measuring right ventricular systolic function in patients with pulmonary hypertension.

Methods

Patients with pulmonary hypertension (n = 23) underwent cardiac magnetic resonance, 2DE, and RT3DE. Specifically, 2DE was used to measure the right ventricular index of myocardial performance (RIMP), fractional area change, tricuspid annular plane systolic excursion (TAPSE), and tissue Doppler-derived tricuspid annular systolic velocity (S′). Cardiac magnetic resonance and RT3DE were used to measure right ventricular end-diastolic volume (RVEDV) and end-systolic volume (RVESV). The right ventricular ejection fraction (RVEF) was calculated.

Results

Regarding the measurements taken by 2DE, RVEF positively correlated with fractional area change (r = 0.595, P = 0.003) and S′(r = 0.489, P = 0.018), and negatively correlated with RIMP (r = −0.745, P = 0.000). There was no association between RVEF and TAPSE (r = −0.029, P = 0.896). There existed a close correlation between the values of RVEDV, RVESV, and RVEF as measured by RT3DE and CMR respectively (P<0.001); Bland-Altmanan analyses showed good agreement between them.

Conclusion

RT3DE was a viable method for noninvasive, accurate assessment of right ventricular systolic function in patients with pulmonary hypertension.

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.

A Hybrid Method for Endocardial Contour Extraction of Right Ventricle in 4-Slices from 3D Echocardiography Dataset

This paper presents a hybrid method to extract endocardial contour of the right ventricular (RV) in 4-slices from 3D echocardiography dataset. The overall framework comprises four processing phases. In Phase I, the region of interest (ROI) is identified by estimating the cavity boundary. Speckle noise reduction and contrast enhancement were implemented in Phase II as preprocessing tasks. In Phase III, the RV cavity region was segmented by generating intensity threshold which was used for once for all frames. Finally, Phase IV is proposed to extract the RV endocardial contour in a complete cardiac cycle using a combination of shape-based contour detection and improved radial search algorithm. The proposed method was applied to 16 datasets of 3D echocardiography encompassing the RV in long-axis view. The accuracy of experimental results obtained by the proposed method was evaluated qualitatively and quantitatively. It has been done by comparing the segmentation results of RV cavity based on endocardial contour extraction with the ground truth. The comparative analysis results show that the proposed method performs efficiently in all datasets with overall performance of 95% and the root mean square distances (RMSD) measure in terms of mean ± SD was found to be 2.21 ± 0.35 mm for RV endocardial contours.

Knowledge-based reconstruction of right ventricular volumes using real-time three-dimensional echocardiographic as well as cardiac magnetic resonance images: comparison with a cardiac magnetic resonance standard

BACKGROUND

Right ventricular volume quantification using real-time three-dimensional echocardiographic (RT3DE) imaging is limited by technical shortcomings of acquisition and quantification. In this study, a two-step approach was used to overcome these limitations. First, a modified acquisition technique for RT3DE imaging was applied, and second, a software tool using knowledge-based reconstruction (KBR) was used. The approach was validated against the gold standard, cardiac magnetic resonance (CMR) imaging, using CMR and RT3DE data sets from healthy children and from patients with congenital heart disease.

METHODS

Sixty individuals (20 healthy persons, 40 with congenital heart defects; age range, 2.3-43.9 years; median age, 11.3 years) consecutively underwent investigation by CMR and RT3DE imaging. CMR data sets were first quantified by the method of disks (MOD) as the standard. Then CMR and RT3DE data sets were quantified using KBR software and compared with the MOD.

RESULTS

CMR was more feasible than echocardiography (100% vs 88%). Compared with the MOD (CMRMOD), there were trivial volume overestimations of KBR for CMR data (CMRKBR), of end-diastolic volume (EDV) (-1.3 ± 8.6%, r = 0.984) and end-systolic volume (ESV) (-3.4 ± 13.3%, r = 0.985), resulting in a 0.7 ± 8.7% difference in ejection fraction (EF) (r = 0.882). Comparing CMRMOD and RT3DE imaging, EDV (1.1 ± 7.4%, r = 0.990) and EF (0.8 ± 9.2%, r = 0.871) were slightly underestimated by RT3DE imaging, with a slight overestimation of ESV (-1.5 ± 13.3%, r = 0.977). Intraobserver variability was excellent for KBR of CMR and RT3DE data, with interclass coefficients of correlation of 0.995 and 0.997 for EDV, 0.995 and 0.994 for ESV, and 0.915 and 0.912 for EF. Interobserver variability provided intraclass correlation coefficients of 0.992 and 0.990 for EDV, 0.997 and 0.992 for ESV, and 0.953 and 0.933 for EF. The KBR analysis required a mean time of 5 min.

CONCLUSIONS

KBR is an accurate, versatile, and time-saving method for right ventricular three-dimensional volumetry; it shows excellent reproducibility for RT3DE and CMR data sets. These results suggest that this tool is clinically valuable.

Assessment of right ventricular responses to therapy in pulmonary hypertension

Irrespective of its cause, pulmonary hypertension (PH) leads to an increase in pulmonary vascular resistance (PVR). Failing adaption of the right ventricle (RV) to the increased afterload is the main cause of death in PH patients and therefore monitoring RV function during treatment is essential. However, consensus on the optimal method for serial assessment of RV function is lacking and therefore the major clinical trials on PH-specific therapies have not provided clear answers with respect to the response of the RV to treatment. This short review will give an overview of the most important load-dependent and load-independent parameters for assessing RV response to therapy in PH patients.