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

Background: Three-dimensional echocardiography (3DE) and semi-automatic right ventricular delineation has been proposed as an appropriate method for right ventricle (RV) evaluation. We aimed to examine how manual correction of semi-automatic delineation influences the accuracy of 3DE for RV volumes and function in a clinical adult setting using cardiac magnetic resonance (CMR) as the reference method. We also examined the feasibility of RV visualization with 3DE. Methods: 62 non-selected patients were examined with 3DE (Sonos 7500 and iE33) and with CMR (1.5T). Endocardial RV contours of 3DE-images were semi-automatically assessed and manually corrected in all patients. End-diastolic (EDV), end-systolic (ESV) volumes, stroke volume (SV) and ejection fraction (EF) were computed. Results: 53 patients (85%) had 3DE-images feasible for examination. Correlation coefficients and Bland Altman biases between 3DE with manual correction and CMR were r = 0.78, -22 +/- 27 mL for EDV, r = 0.83, -7 +/- 16 mL for ESV, r = 0.60, -12 +/- 18 mL for SV and r = 0.60, -2 +/- 8% for EF (p < 0.001 for all r-values). Without manual correction r-values were 0.77, 0.77, 0.70 and 0.49 for EDV, ESV, SV and EF, respectively (p < 0.001 for all r-values) and biases were larger for EDV, SV and EF (-32 +/- 26 mL, -21 +/- 15 mL and -6 +/- 9%, p <= 0.01 for all) compared to manual correction. Conclusion: Manual correction of the 3DE semi-automatic RV delineation decreases the bias and is needed for acceptable clinical accuracy. 3DE is highly feasible for visualizing the RV in an adult clinical setting

Three-dimensional assessment of cardiac function; When right is wrong

Assessment of the right side of the heart is important in patients with heart disease; especially in patient with elevated pressure in the lung circulation. Decreased right ventricular function and elevated pressure in the right atrium are of poor prognostic value. Two-dimensional echocardiography (ultrasound of the heart) is the most commonly used method to assess the hearts function, but the right ventricle is hard to assess with this method. This is partly due to a 2-dimensional method has intrinsic problems to assess a 3-dimensional complex structure such as the right side of the heart. Magnetic resonance imaging of the heart and 3-dimensional (3D) echocardiography can be used for imaging in three dimensions. The aim of this thesis is to assess how 3D echocardiography and magnetic resonance imaging of the heart can be used to determine the right heart function; and due to this determine how the heart pump physiology is altered by elevated right atrial and pulmonary pressure. In this thesis, echocardiography and magnetic resonance imaging is used with 2D and 3D technique. Study I showed how to acquire 3D echocardiography for volume assessment of both atria and ventricles in adult cardiac patients. Acquisition from the apex of the heart, with at times an 'off-axis' approach, should be used for volumetric assessment with 3D echocardiography. While the atria and the left ventricle were well visualized, the right ventricle was a challenge. Study II aimed to validated right ventricular volumes and function, in a population of adult cardiac patients, with 3D echocardiography using magnetic resonance imaging as a reference. The study showed the difficulty to asses right ventricular volumes and function, even when using 3D echocardiography in a clinically unselected population. Furthermore, the study showed the importance of manual corrections to achieve reasonably valid measurements, when compared to magnetic resonance imaging. Study III assessed elevated right atrial pressure by quantifying right atrial volumes with 3D echocardiography in patients with elevated pressure in the lung circulation. The volumes were compared to invasively measured pressure values and magnetic resonance imaging. The study showed that 3D as well as 2D echocardiographic volume assessment of the right atrium were better than the conventional echocardiographic methods to determine elevated right atrial pressure. This was despite a substantial underestimation of the 3D echocardiographic volumes compared to magnetic resonance imaging. Study IV examined the different contributions to right and left ventricular stroke volume in patients with elevated pressure in the lung circulation; and compared to those of healthy adults. Magnetic resonance imaging was used given the results of study II and pressure was quantified by right sided catheterization. The study showed that longitudinal and lateral contribution to left ventricular stroke volume was altered in patients with elevated pressure in the lung circulation compared to the control group. Right ventricular longitudinal and lateral contribution to stroke volume did not differ between patients and controls. The septum moved to the left in both groups, however less in patients than in healthy adults. In patients with elevated pressure in the lung circulation and hence pressure loaded right ventricles, the different components of pump function are altered in a different compared to volume loaded right ventricles. This is new information that helps understand the hearts physiology

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

Cardiac Magnetic Resonance Imaging in Pulmonary Arterial Hypertension: Ready for Clinical Practice and Guidelines?

Purpose of Review Pulmonary arterial hypertension (PAH) is a progressive disease with high mortality. A greater understanding of the physiology and function of the cardiovascular system in PAH will help improve survival. This review covers the latest advances within cardiovascular magnetic resonance imaging (CMR) regarding diagnosis, evaluation of treatment, and prognostication of patients with PAH. Recent Findings New CMR measures that have been proven relevant in PAH include measures of ventricular and atrial volumes and function, tissue characterization, pulmonary artery velocities, and arterio-ventricular coupling. Summary CMR markers carry prognostic information relevant for clinical care such as treatment response and thereby can affect survival. Future research should investigate if CMR, as a non-invasive method, can improve existing measures or even provide new and better measures in the diagnosis, evaluation of treatment, and determination of prognosis of PAH

Risk assessment in PAH using quantitative CMR tricuspid regurgitation : relation to heart catheterization

AIMS: Improved risk stratification is of value for decision making in pulmonary arterial hypertension (PAH). Right heart catheterization combined with quantitative tricuspid regurgitation (TR) by cardiovascular magnetic resonance (CMR) may provide this. The aims were to study: (i) to what extent quantitative TR is associated with event-free survival; (ii) how quantitative TR is related to known prognostic markers in PAH; and (iii) to what extent quantitative TR and right atrial pressure determine right atrial dilation.METHODS AND RESULTS: Fifty patients (63 ± 17 years) with PAH referred for CMR were included. Volumes and pulmonary artery flow by CMR and pressure and vascular resistance by right heart catheterization were obtained. Composite outcome was lung transplantation or death. Four transplantations and 27 deaths occurred over a median of 2.7 years. A trend towards higher hazard ratio was shown for TR volume (TRV; 2.1, 95% CI 1.0-4.4) and TR fraction (TR%; 1.6, 95% CI 0.8-3.3) above median. TRV and TR% correlated with right ventricular (RV) end-diastolic (TRV r = 0.50; TR% r = 0.39) and end-systolic (TRV r = 0.35; TR% r = 0.30) volumes, pulmonary vascular resistance (TRV r = 0.28; TR% r = 0.43), N terminal pro brain natriuretic peptide (TRV r = 0.65; TR% r = 0.68), cardiac index (TRV r = -0.32; TR% r = -0.54), pulmonary artery stroke volume (TRV r = -0.32; TR% r = -0.58) and effective RV ejection fraction by pulmonary artery quantitative flow (TRV r = -0.56; TR% r = -0.69), but not RVEF. Both TR% and right atrial pressure determined right atrial volumes (r2 = 0.38; r2 = 0.48).CONCLUSIONS: A clear trend towards worse outcome with larger TRV or TR% was shown; however, the number of events was insufficient for significant outcome differences. Prognostic value of quantitative TR should be investigated in a larger multicentre cohort. Effective RV ejection fraction may be considered an improved measure of RV function in PAH

Comparison of different views with three-dimensional echocardiography: apical views offer superior visualization compared with parasternal and subcostal views.

Studies seeking to validate real-time three-dimensional echocardiography (3DE) with regard to cardiac function and dimensions have almost exclusively used apical views. However, it has never been examined whether apical views are preferable to parasternal or subcostal views. In the present study, we compared the feasibility of 3DE volumetric measurements of the four heart chambers in three different views. We included 40 patients planned for a routine two-dimensional transthoracic echocardiography examination (2DE). All patients were scanned with both 2DE and 3DE (Sonos 7500; Philips Medical Systems Andover, MA, USA). Parasternal, apical and subcostal views were used for 3DE. Volumes were calculated using manual tracing in 16 planes. 2DE was performed in parasternal longaxis, subcostal and apical four- and two-chamber views. Manual tracing was used for area calculations. To be judged fully traceable, 5/6 (85%) or more of the ventricular and atrial walls had to be adequately visualized in each plane. The left ventricle and left atrium were adequately visualized in the 3DE apical view in 34 (85%) and 40 (100%) patients, respectively. Visualization of the right atrium was adequate in 31 (78%) patients, whereas the right ventricle was adequately visualized in only 12 (30%) patients. The apical view of 3DE provided superior visualization of all four heart chambers compared with the parasternal and subcostal views, when applying a slight off-axis approach for both ventricles when needed. Thus, in the present study, there was no incremental value of assessment of chamber volumes in the parasternal and subcostal views