Improved quantification of left ventricular mass based on endocardial and epicardial surface detection with real time three dimensional echocardiography

Validating real-time three-dimensional echocardiography against cardiac magnetic resonance, for the determination of ventricular mass, volume and ejection fraction: a meta-analysis

INTRODUCTION

Real-time three-dimensional echocardiography (RT3DE) is currently being developed to overcome the challenges of two-dimensional echocardiography, as it is a much cheaper alternative to the gold standard imaging method, cardiac magnetic resonance (CMR). The aim of this meta-analysis is to validate RT3DE by comparing it to CMR, to ascertain whether it is a practical imaging method for routine clinical use.

METHODS

A systematic review and meta-analysis method was used to synthesise the evidence and studies published between 2000 and 2021 were searched using a PRISMA approach. Study outcomes included left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), left ventricular mass (LVM), right ventricular end-systolic volume (RVESV), right ventricular end-diastolic volume (RVEDV) and right ventricular ejection fraction (RVEF). Subgroup analysis included study quality (high, moderate), disease outcomes (disease, healthy and disease), age group (50 years old and under, over 50 years), imaging plane (biplane, multiplane) and publication year (2010 and earlier, after 2010) to determine whether they explained the heterogeneity and significant difference results generated on RT3DE compared to CMR.

RESULTS

The pooled mean differences for were - 5.064 (95% CI - 10.132, 0.004, p > 0.05), 4.654 (95% CI - 4.947, 14.255, p > 0.05), - 0.783 (95% CI - 5.630, 4.065, p > 0.05, - 0.200 (95% CI - 1.215, 0.815, p > 0.05) for LVEF, LVM, RVESV and RVEF, respectively. We found no significant difference between RT3DE and CMR for these variables. Although, there was a significant difference between RT3DE and CMR for LVESV, LVEDV and RVEDV where RT3DE reports a lower value. Subgroup analysis indicated a significant difference between RT3DE and CMR for studies with participants with an average age of over 50 years but no significant difference for those under 50. In addition, a significant difference between RT3DE and CMR was found in studies using only participants with cardiovascular diseases but not in those using a combination of diseased and healthy participants. Furthermore, for the variables LVESV and LVEDV, the multiplane method shows no significant difference between RT3DE and CMR, as opposed to the biplane showing a significant difference. This potentially indicates that increased age, the presence of cardiovascular disease and the biplane analysis method decrease its concordance with CMR.

CONCLUSION

This meta-analysis indicates promising results for the use of RT3DE, with limited difference to CMR. Although in some cases, RT3DE appears to underestimate volume, ejection fraction and mass when compared to CMR. Further research is required in terms of imaging method and technology to validate RT3DE for routine clinical use.

Clinical Utility of Three-Dimensional Echocardiography in the Evaluation of Mitral Valve Disease: Tips and Tricks

Although real-time 3D echocardiography (RT3DE) has only been introduced in the last decades, its use still needs to be improved since it is a time-consuming and operator-dependent technique and acquiring a good quality data can be difficult. Moreover, the additive value of this important diagnostic tool still needs to be wholly appreciated in clinical practice. This review aims at explaining how, why, and when performing RT3DE is useful in clinical practice.

3D Echocardiography for Rheumatic Heart Disease Analysis: Ready for Prime Time

Rheumatic heart disease (RHD) remains to be a very important health issue worldwide, mainly in underdeveloped countries. It continues to be a leading cause of morbidity and mortality throughout developing countries. RHD is a delayed non-suppurative immunologically mediated inflammatory response to the throat infection caused by a hemolytic streptococcus from the A group (Streptococcus pyogenes). RHD keeps position 1 as the most common cardiovascular disease in young people aged <25 years considering all the continents. The disease can lead to valvular cardiac lesions as well as to carditis. Rheumatic fever valvular injuries lead most commonly to the fusion and thickening of the edges of the cusps and to the fusion, thickening, and shortening of the chordae and ultimately to calcification of the valves. Valvular commissures can also be deeply compromised, leading to severe stenosis. Atrial and ventricular remodeling is also common following rheumatic infection. Mixed valvular lesions are more common than isolated valvular disorders. Echocardiography is the most relevant imaging technique not only to provide diagnostic information but also to enable prognostic data. Further, it presents a very important role for the correction of complications after surgical repair of rheumatic heart valvulopathies. Three-dimensional (3D) echocardiography provides additional anatomical and morphofunctional information of utmost importance for patients presenting rheumatic valvopathies. Accordingly, three-dimensional echocardiography is ready for routine use in patients with RHD presenting with valvular abnormalities.

Echocardiographic Left Ventricular Mass Estimation: Two-Dimensional Area-Length Method is Superior to M-Mode Linear Method in Swine Models of Cardiac Diseases

Echocardiography offers rapid and cost-effective estimations of left ventricular (LV) mass, but its accuracy in patients with cardiac disease remains unclear. LV mass was measured by M-mode-based linear method and two-dimensional echocardiography (2DE)-based area-length method in pig models and correlation with actual LV weight was assessed. Twenty-six normal, 195 ischemic heart disease (IHD), and 33 non-IHD HF pigs were included. A strong positive linear relationship to the actual LV weight was found with 2DE-based area-length method (r = 0.82, p < 0.001), whereas a moderate relationship was found with M-mode method in the overall population (r = 0.68, p < 0.001). Two correlation coefficients were significantly different (p < 0.001), and were driven mainly by incremental overestimation of LV mass in heavier hearts using the M-mode method. IHD and LV dilation were the factors contributing to overestimation using M-mode method. 2DE-based area-length method provides a better estimation of LV weight in swine models of HF, particularly in those with IHD.

Myocardial Oxygen Consumption and Efficiency in Patients With Cardiac Amyloidosis

Background

This study evaluated myocardial oxygen consumption (MVO₂) and myocardial external efficiency (MEE) in patients with cardiac amyloidosis (CA). Furthermore, we compared MEE and MVO₂ in subjects with light chain amyloidosis versus transthyretin (ATTR) amyloidosis.

Methods and Results

The study population comprised 40 subjects: 25 patients with confirmed CA and 15 control subjects. All subjects underwent an ¹¹C‐acetate positron emission tomography. Furthermore, the CA patients underwent comprehensive echocardiography and right heart catheterization during a symptom‐limited, semi‐supine exercise test. MEE was calculated from ¹¹C‐acetate positron emission tomography as the ratio of left ventricular (LV) stroke work and the energy equivalent of MVO₂. Myocardial work efficiency was calculated as echocardiography‐derived work pressure product divided by three‐dimensional LV mass. CA patients had significantly lower LV‐ejection fraction (54±13% versus 63±4%, P<0.05) and LV‐global longitudinal strain (LVGLS) (12±4% versus 19±2%, P<0.0001) and a more restrictive filling pattern (E/e′‐ratio 18 [12–25] versus 8 [7–9], P<0.0001) than controls. MEE was severely reduced (13±5% versus 22±5%, P<0.0001) whereas total MVO₂ was higher (18±6 mL/min versus 13±3 mL/min, P<0.01) in CA patients than controls. MEE decreased with increasing New York Heart Association symptom burden (P<0.0001). We found a good relationship between MEE and peak exercise systolic performance (LVGLS: R²=0.60, P<0.0001; myocardial work efficiency: R²=0.48, P<0.0001; cardiac index: R²=0.52, P<0.0001) and between MEE and myocardial blood flow (R²=0.44, P<0.0001).

Conclusion

Myocardial oxidative metabolism is disturbed in CA patients with increased total MVO₂ and reduced MEE. MEE correlated significantly with echocardiographic derived systolic parameters such as myocardial work efficiency and LVGLS that might be used as surrogate MEE markers.

Pretransplant Cardiac Evaluation Using Novel Technology

Hematopoietic stem-cell transplantation (HSCT) is a complex procedure that has been increasingly successful in treating malignant and nonmalignant conditions. Despite its effectiveness, it can be associated with potentially life-threatening adverse effects. New onset heart failure, ischemic disease, and arrhythmias are among the most notable cardiovascular complications post-HSCT. As a result, appropriate cardiac risk stratification prior to transplant could result in decreased morbidity and mortality by identifying patients with a higher probability of tolerating possible toxicities associated with HSCT. In this review, we aim to discuss the utility of cardiac screening using novel modalities of imaging technology in the pre-HSCT phase.

Automated, machine learning-based, 3D echocardiographic quantification of left ventricular mass

BACKGROUND

Although 3D echocardiography (3DE) circumvents many limitations of 2D echocardiography by allowing direct measurements of left ventricular (LV) mass, it is seldom used in clinical practice due to time-consuming analysis. A recently developed 3DE machine learning (ML) approach allows automated determination of LV mass. We aimed to evaluate the accuracy of this new approach by comparing it to cardiac magnetic resonance (CMR) reference and to conventional 3DE volumetric analysis.

METHODS

We prospectively studied 23 patients who underwent 3DE (Philips EPIQ) and CMR imaging on the same day. Single-beat wide-angle 3D datasets of the left ventricle were acquired. LV mass was quantified using the new automated software (Philips HeartModel) with manual corrections when necessary and using conventional volumetric analysis (TomTec). CMR analysis was performed by manual slice-by-slice tracing of LV endo- and epicardial boundaries. Reproducibility of the ML approach was assessed using repeated measurements and quantified by intra-class correlation (ICC) and coefficients of variation (CoV).

RESULTS

Automated LV mass measurements were feasible in 20 patients (87%). The results were similar to CMR-derived values (Bland-Altman bias 5 g, limits of agreement ±37 g) and also to the conventional 3DE analysis (bias 7 g, ±27 g). Processing time was considerably shorter: 1.02 ± 0.24 minutes (CMR: 2.20 ± 0.13 minutes; TomTec: 2.36 ± 0.09 minutes), although manual corrections were performed in most patients. Repeated measurements showed high reproducibility: ICC = 0.99; CoV = 4 ± 5%.

CONCLUSIONS

3D Echocardiography analysis of LV mass using novel ML-based algorithm is feasible, fast, and accurate and may thus facilitate the incorporation of 3DE measurements of LV mass into clinical practice.

Abnormal Coronary Flow Velocity Reserve and Decreased Myocardial Contractile Reserve Are Main Factors in Relation to Physical Exercise Capacity in Cardiac Amyloidosis

BACKGROUND

The aim of the present study was to evaluate the clinical importance of echocardiographic coronary flow velocity reserve (CFVR), resting and exercise left ventricular global longitudinal strain (LVGLS), and myocardial work efficiency (MWE) in patients with cardiac amyloidosis (CA).

METHODS

The study population comprised 69 subjects: group A, 27 patients with CA confirmed by endomyocardial biopsy (CA positive); group B, 42 healthy control subjects. The amyloid phenotype in group A was as follows: patients with wild-type transthyretin-related amyloidosis (n = 10), carriers of the Danish familial transthyretin amyloidosis mutation with cardiac involvement (n = 5), and patients with amyloid light chain amyloidosis with cardiac involvement (n = 12). All subjects underwent comprehensive echocardiographic evaluation during rest and during symptom-limited, semisupine exercise testing. Furthermore, CFVR was assessed using Doppler echocardiography.

RESULTS

Patients with CA had significantly lower CFVR (1.7 ± 0.6 vs 3.9 ± 0.8, P < .0001), MWE (1.9 ± 1.0 vs 3.0 ± 0.7, P < .0001), and LVGLS magnitude (11% [10%-14%] vs 20% [18%-21%], P < .0001) than control subjects. Patients with CA showed severely reduced deformation and efficiency reserve compared with control subjects (ΔLVGLS 0.9 ± 2.8% vs 5.6 ± 2.3%, P < .0001; ΔMWE 2.5 ± 2.8 vs 8.8 ± 2.6, P < .0001). In patients with CA, a strong relation was seen between physical capacity by the metabolic equivalent of tasks test and CFVR (r = 0.55, P < .01), peak exercise LVGLS (r = 0.64, P < .0001), and peak exercise MWE (r = 0.60, P < .01).

CONCLUSIONS

Patients with CA had a profound lack of CFVR and longitudinal myocardial deformation reserve compared with healthy control subjects. Both parameters were significantly associated with exercise capacity and may prove useful for evaluating cardiac performance in patients with CA.

Real-Time Three-Dimensional Echocardiography: Characterization of Cardiac Anatomy and Function-Current Clinical Applications and Literature Review Update

Our review of real-time three-dimensional echocardiography (RT3DE) discusses the diagnostic utility of RT3DE and provides a comparison with two-dimensional echocardiography (2DE) in clinical cardiology. A Pubmed literature search on RT3DE was performed using the following key words: transthoracic, two-dimensional, three-dimensional, real-time, and left ventricular (LV) function. Articles included perspective clinical studies and meta-analyses in the English language, and focused on the role of RT3DE in human subjects. Application of RT3DE includes analysis of the pericardium, right ventricular (RV) and LV cavities, wall motion, valvular disease, great vessels, congenital anomalies, and traumatic injury, such as myocardial contusion. RT3DE, through a transthoracic echocardiography (TTE), allows for increasingly accurate volume and valve motion assessment, estimated LV ejection fraction, and volume measurements. Chamber motion and LV mass approximation have been more accurately evaluated by RT3DE by improved inclusion of the third dimension and quantification of volumetric movement. Moreover, RT3DE was shown to have no statistical significance when comparing the ejection fractions of RT3DE to cardiac magnetic resonance (CMR). Analysis of RT3DE data sets of the LV endocardial exterior allows for the volume to be directly quantified for specific phases of the cardiac cycle, ranging from end systole to end diastole, eliminating error from wall motion abnormalities and asymmetrical left ventricles. RT3DE through TTE measures cardiac function with superior diagnostic accuracy in predicting LV mass, systolic function, along with LV and RV volume when compared with 2DE with comparable results to CMR.

Left Ventricular Myocardial Segmentation in 3-D Ultrasound Recordings: Effect of Different Endocardial and Epicardial Coupling Strategies

Cardiac volume/function assessment remains a critical step in daily cardiology, and 3-D ultrasound plays an increasingly important role. Though development of automatic endocardial segmentation methods has received much attention, the same cannot be said about epicardial segmentation, in spite of the importance of full myocardial segmentation. In this paper, different ways of coupling the endocardial and epicardial segmentations are contrasted and compared with uncoupled segmentation. For this purpose, the B-spline explicit active surfaces framework was used; 27 3-D echocardiographic images were used to validate the different coupling strategies, which were compared with manual contouring of the endocardial and epicardial borders performed by an expert. It is shown that an independent segmentation of the endocardium followed by an epicardial segmentation coupled to the endocardium is the most advantageous. In this way, a framework for fully automatic 3-D myocardial segmentation is proposed using a novel coupling strategy.

Principles of transthoracic echocardiographic evaluation

Transthoracic echocardiography is the most widely used imaging test in cardiology. Although completely noninvasive, transthoracic echocardiography has a well-established role in the diagnosis of numerous cardiovascular diseases, and also provides critical qualitative and quantitative information on their prognosis and pathophysiological processes. The aim of this Review is to outline the broad principles of transthoracic echocardiography, including the traditional techniques of two-dimensional, colour, and spectral Doppler echocardiography, and newly developed advances including tissue Doppler, myocardial deformation imaging, torsion, stress echocardiography, contrast and three-dimensional echocardiography. The advantages and disadvantages, clinical application, prognostic value, and salient research findings of each modality are described. Advances in complex imaging techniques are expected to continue unabated, and this Review highlights technical improvements that will influence the diagnosis and improve our understanding of cardiovascular function and disease.

The clinical benefits of adding a third dimension to assess the left ventricle with echocardiography

Three-dimensional echocardiography is a novel imaging technique based on acquisition and display of volumetric data sets in the beating heart. This permits a comprehensive evaluation of left ventricular (LV) anatomy and function from a single acquisition and expands the diagnostic possibilities of noninvasive cardiology. It provides the possibility of quantitating geometry and function of LV without preestablished assumptions regarding cardiac chamber shape and allows an echocardiographic assessment of the LV that is less operator-dependent and therefore more reproducible. Further developments and improvements for widespread routine applications include higher spatial and temporal resolution to improve image quality, faster acquisition, processing and reconstruction, and fully automated quantitative analysis. At present, three-dimensional echocardiography complements routine 2DE in clinical practice, overcoming some of its limitations and offering additional valuable information that has led to recommending its use for routine assessment of the LV of patients in whom information about LV size and function is critical for their clinical management.

Comparison of three-dimensional echocardiographic findings to those of magnetic resonance imaging for determination of left ventricular mass in patients with ischemic and non-ischemic cardiomyopathy

The standard echocardiographic evaluation of left ventricular (LV) mass, particularly in ischemic cardiomyopathy (IC) is challenging because it is based on geometric assumptions. The aim of this study was to assess the accuracy of LV mass calculation using echocardiographic modalities compared with cardiac magnetic resonance (CMR) in IC and in nonischemic cardiomyopathy (non-IC). Echocardiography was performed in 104 patients (mean age 55 ± 15 years) referred for CMR: 63 with IC and 41 with non-IC. CMR, M-mode echocardiography, 2-dimensional echocardiography, and 3-dimensional echocardiography (3DE) were analyzed using standard commercial tools to obtain LV mass. LV mass on 3DE showed a higher correlation with CMR than 2-dimensional echocardiography (r = 0.87 vs r = 0.70, p <0.001). M-mode echocardiography overestimated LV mass (bias +30%) and 2-dimensional echocardiography underestimated LV mass (bias -11%), whereas measurements on 3DE showed only minimal bias (-2%). LV mass on 3DE in non-IC showed a significantly higher correlation with CMR than in IC (r = 0.92 vs r = 0.84, z = 2.3, p <0.05). In non-IC, the mean difference was -2 g (-1% of the mean), with 95% limits of agreement of ±33 g (±19% of the mean). In IC, the mean difference was -7 g (-4% of the mean), with limits of agreement of ±56 g (±31% of the mean). There was a correlation between the absolute LV mass differences (3DE derived and CMR derived) and scar percentage (infarcted mass/total LV mass) using delayed-hyperenhancement images (r = 0.40, p <0.05). The net reclassification index with 3DE was +16% for concentric LV hypertrophy. In conclusion, the most accurate and reliable echocardiographic measurement of LV mass is 3DE, but underestimation and variability remain challenges in IC.

Three-dimensional echocardiography in evaluation of left ventricular indices

Accurate determination of left ventricular mass, volume, ejection fraction, and wall motion is important for clinical decision making. Currently, M-mode and two-dimensional echocardiography (2DE) have been routinely used for this purpose. Although these 1D or 2D modalities provide excellent diagnostic and prognostic information, they have a number of technical limitations including the time required to perform the procedure and operator-dependent image acquisitions. In addition, they are inherently limited by geometric assumption of three-dimensional (3D) left ventricular structures based on 2D slices. With the improvement in transducer technology and software development, 3D echocardiography (3DE) has become widely available. Left ventricular quantitation by 3DE has been demonstrated to be accurate by multiple studies that compared 3DE with reference techniques. In addition, 3DE measurements were found to be more reproducible and less variable than 2DE. Real time 3DE imaging has potential advantages in stress echocardiography including rapid acquisition, unlimited number of planes, avoidance of foreshortening, and precise segment matching. This is a major step forward in our diagnostic armamentarium for the evaluation of ischemia. In this review, we summarized the current evidence of 3DE for left ventricular evaluation.

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.

Meta-analysis of accuracy of left ventricular mass measurement by three-dimensional echocardiography

Left ventricular (LV) hypertrophy is a fundamental prognostic factor in a variety of cardiac diseases. Three-dimensional echocardiography (3DE) has achieved better estimation of LV mass than 2-dimensional echocardiography. However, significant underestimation has often been reported, and no previous study has synthesized these data. The aim of this meta-analysis was to investigate if there has been improvement in the accuracy in LV mass measurement by 3DE over time. Studies comparing LV mass between 3DE and magnetic resonance imaging were eligible. A cumulative meta-analysis was performed to investigate improvement in accuracy, followed by subgroup and meta-regression analysis to reveal factors affecting the bias. A total of 25 studies including 671 comparisons were analyzed. Studies published in or before 2004 showed high heterogeneity (I(2) = 69%) and significant underestimation of LV mass by 3DE (-5.7 g, 95% confidence interval -11.3 to -0.2, p = 0.04). Studies published from 2005 to 2007 were still heterogenous (I(2) = 60%) but showed less systematic bias (-0.5 g, 95% confidence interval -2.5 to 1.5, p = 0.63). In contrast, studies published in or after 2008 were highly homogenous (I(2) = 3%) and showed excellent accuracy (-0.1 g, 95% confidence interval -2.2 to 1.9, p = 0.90). Investigation of factors affecting the bias revealed that evaluation of cardiac patients compared to healthy volunteers led to larger bias (p <0.05). In conclusion, this meta-analysis elucidates the underestimation of LV mass by 3DE, its improvement over the past decade, and factors affecting the bias. These data provide a more detailed basis for improving the accuracy of 3DE, an indispensable step toward further clinical application.

Statistical agreement of left ventricle measurements using cardiac magnetic resonance and 2D echocardiography in ischemic heart failure

Background

The aim of this study was to compare cardiac magnetic resonance imaging (CMR) with 2-dimensional echocardiography (2D echo) in the assessment of left ventricle (LV) function parameters and mass in patients with ischemic heart disease and severely depressed LV function. Although 2D echo is commonly used to assess LV indices, CMR is the state-of-the-art technique. Agreement between these 2 methods in these patients has not been well established.

Material/Methods

LV indexed end systolic and diastolic volumes (EDVi and ESVi), indexed mass (LVMi) and ejection fraction (EF) were assessed in 67 patients (12 women), using 2D echo and CMR.

Results

According to statistical analysis (Bland-Altman), 2D echo underestimated LV EDV and ESV and overestimated EF and LVMi compared to CMR. The highest correlation between 2D echo and CMR was found for EDVi (R²=0.73, p<0.0001) and ESVi (R²=0.69, p<0.0001) and the lowest for EF (R²=0.21, p=0.001) and LVMi (R²=0.20, p=0.002). The maximal differences between 2D echo and CMR were found for highest mesurements of LV volumes and mass, and for lowest EF values.

Conclusions

There is moderate to strong correlation between CMR and 2D echo in the assessment of LV function parameters and mass in patients with ischemic heart failure. Between-method agreement depends on the degree of LV dysfunction. The results of assessment of the severely damaged LV obtained by the use of 2D echo should be interpreted with caution.

Current clinical applications of transthoracic three-dimensional echocardiography

The advent of three-dimensional echocardiography (3DE) has significantly improved the impact of non-invasive imaging on our understanding and management of cardiac diseases in clinical practice. Transthoracic 3DE enables an easier, more accurate and reproducible interpretation of the complex cardiac anatomy, overcoming the intrinsic limitations of conventional echocardiography. The availability of unprecedented views of cardiac structures from any perspective in the beating heart provides valuable clinical information and new levels of confidence in diagnosing heart disease. One major advantage of the third dimension is the improvement in the accuracy and reproducibility of chamber volume measurement by eliminating geometric assumptions and errors caused by foreshortened views. Another benefit of 3DE is the realistic en face views of heart valves, enabling a better appreciation of the severity and mechanisms of valve diseases in a unique, noninvasive manner. The purpose of this review is to provide readers with an update on the current clinical applications of transthoracic 3DE, emphasizing the incremental benefits of 3DE over conventional two-dimensional echocardiography.

Current cardiac imaging techniques for detection of left ventricular mass

Estimation of left ventricular (LV) mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE) is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR) and cardiovascular computed tomography (CCT) are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test.

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.

Cardiac assessment in chronic kidney disease

Patients with chronic kidney disease are well recognized to develop a wide range of cardiac structural and functional abnormalities. These changes may be progressive and relate directly to a grossly aggravated risk of cardiovascular events and reduced survival. Although conventional methods of cardiac assessment have been shown to be useful, they are limited by insufficient sensitivity and specificity, to fully appreciate the overall degree of myocardial distress that is common in these patients. This article aims to review the use of established and emerging cardiac imaging tools and, in particular, their application in patients with chronic kidney disease.

Comparison of methods to measure heart size using noncontrast-enhanced computed tomography: correlation with left ventricular mass

OBJECTIVE

Left ventricular (LV) mass is a useful independent predictor of cardiovascular events. We sought to develop a new correlate of LV mass using noncontrast-enhanced cardiac computed tomography (NCE-CCT).

METHODS

We assessed 22 different ventricular measurements made with NCE-CCT in 60 participants in the Multi-Ethnic Study of Atherosclerosis. The primary outcome was the correlation between the NCE-CCT measurements and magnetic resonance imaging (MRI)-derived LV mass.

RESULTS

Correlation coefficients (r) for the 22 NCE-CCT techniques in comparison to MRI-derived LV mass ranged from 0.12 to 0.80, with 14 of the 22 techniques having r > 0.7. The highest correlation was achieved using the modified Simpson Rule method to determine the biventricular volume (r = 0.80; P < 0.001). Interrater reliability was good, with intraclass correlation coefficients of 0.84 to 0.90 for the best (r > 0.75) NCE-CCT methods.

CONCLUSIONS

Noncontrast-enhanced cardiac computed tomography measurements of both biventricular volume and LV volume correlated well with MRI-derived LV mass in a population free of clinical cardiovascular disease.

Real-time three-dimensional echocardiographic assessment of left ventricular remodeling index in patients with hypertensive heart disease and coronary artery disease

Left ventricular remodeling index (LVRI) was assessed in patients with hypertensive heart disease (HHD) and coronary artery disease (CAD) by real-time three-dimensional echocardiography (RT3DE). RT3DE data of 18 patients with HHD, 20 patients with CAD and 22 normal controls (NC) were acquired. Left ventricular end-diastolic volume (EDV) and left ventricular end-diastolic epicardial volume (EDVepi ) were detected by RT3DE and two-dimensional echocardiography Simpson biplane method (2DE). LVRI (left ventricular mass /EDV) was calculated and compared. The results showed that LVRI measurements detected by RT3DE and 2DE showed significant differences inter-groups (P<0.01). There was no significant difference in NC group (P>0.05), but significant difference in HHD and CAD intra-group (P<0.05). There was good positive correlations between LVRI detected by RT3DE and 2DE in NC and HHD groups (r=0.69, P<0.01; r=0.68, P<0.01), but no significant correlation in CAD group (r=0.30, P>0.05). It was concluded that LVRI derived from RT3DE as a new index for evaluating left ventricular remodeling can provide more superiority to LVRI derived from 2DE.

Measurement of left ventricular mass by real-time three-dimensional echocardiography: validation against magnetic resonance and comparison with two-dimensional and m-mode measurements

BACKGROUND

The recent development of 3-dimensional (3D) surface detection algorithm of the endocardial and epicardial surfaces from real-time 3D echocardiographic (RT3DE) datasets allows direct semiautomated quantification of left ventricular mass (LVM). Our aims were to (1) evaluate the accuracy of RT3DE measurements of LVM using this algorithm against cardiac magnetic resonance (CMR) reference and (2) compare RT3DE LVM with conventional M-mode, 2-dimensional (2D), and RT3DE-guided biplane measurements.

METHODS

A total of 205 patients were studied in 2 protocols: (1) RT3DE and CMR imaging was performed on the same day in 55 subjects; (2) in an additional 150 subjects, RT3DE, 2D, and M-mode images were acquired. In both protocols, RT3DE endocardial and epicardial surfaces were semiautomatically identified at end diastole (QLab, Philips Medical Systems, Andover, MA) to calculate LVM. CMR, 2D, and M-mode-derived LVM were obtained using standard techniques.

RESULTS

A significant correlation (r = 0.95) was noted between RT3DE and CMR-derived LVM with a small bias of -2 g. M-mode-derived LVM measurements (175 +/- 64 g) were significantly larger than RT3DE LVM (123 +/- 39 g, bias: 52 g) with moderate correlation (r = 0.76). No significant differences in LVM were noted between 2D (125 +/- 42 g) and RT3DE values (bias: 1.2 g) with good correlation (r = 0.91, P < .001). However, the best correlation was noted between RT3DE and RT3DE-guided biplane LVM values (r = 0.95, P < .001, bias: -4.6 g). Intraobserver, interobserver variability, and test-retest variability of the RT3DE measurements were 9%, 12%, and 6%, respectively.

CONCLUSION

RT3DE imaging using the 3D surface detection algorithm allows accurate and reproducible measurements of LVM. RT3DE-guided biplane technique can be used as an accurate time-saving alternative in clinical practice.

Semi-automated analysis of dynamic changes in myocardial contrast from real-time three-dimensional echocardiographic images as a basis for volumetric quantification of myocardial perfusion

AIMS

Despite the potential of real-time three-dimensional (3D) echocardiography (RT3DE) to assess myocardial perfusion, there is no quantification method available for perfusion analysis from RT3DE images. Such method would require 3D regions of interest (ROI) to be defined and adjusted frame-by-frame to compensate for cardiac translation and deformation. Our aims were to develop and test a technique for automated identification of 3D myocardial ROI suitable for translation-free quantification of myocardial videointensity over time, MVI(t), from contrast-enhanced RT3DE images.

METHODS AND RESULTS

Twelve transthoracic RT3DE (Philips) data sets obtained in pigs during transition from no contrast to steady-state enhancement (Definity) were analysed using custom software. Analysis included: (i) semi-automated detection of left ventricular endo- and epicardial surfaces using level-set techniques in one frame to define a 3D myocardial ROI, (ii) rigid 3D registration to reduce translation and rotation, (iii) elastic 3D registration to compensate for deformation, and (iv) quantification of MVI(t) in the 3D ROI from the registered and non-registered data sets to assess the effectiveness of registration. For each MVI(t) curve we computed % variability during steady-state enhancement (100 x SD/mean) and goodness of fit (r2) to the indicator dilution equation MVI(t) = A[1-exp(-betat)]. Analysis of myocardial contrast throughout contrast inflow was feasible in all data sets. Three-dimensional registration improved MVI(t) curves in terms of both % variability (2.8 +/- 1.8 to 1.5 +/- 0.9%; P < 0.05) and goodness of fit (r2 from 0.79 +/- 0.2 to 0.90 +/- 0.1; P < 0.05).

CONCLUSION

This is the first study to describe a new technique for semi-automated volumetric quantification of myocardial contrast from RT3DE images that includes registration and thus provides the basis for 3D measurement of myocardial perfusion.

Real-time three-dimensional echocardiography: an update

Real-time three-dimensional echocardiography (RT3DE) is the only on-line 3D method based on real-time volumetric scanning, as compared with other 3D imaging techniques such as computed tomography and magnetic resonance imaging, which are based on post-acquisition reconstruction and not on volumetric scanning. In recent years, several studies have revealed possible advantages of 3DE in daily clinical practice. The aim of this manuscript is to give a brief review of the development of the clinical applications of RT3DE.

Importance of transesophageal echocardiography in the critically ill and injured patient

Echocardiography, particularly transesophageal echocardiography (TEE), is a vital diagnostic and monitoring imaging modality for the intensivist. The field of echocardiography spans different venues and pathologies, ranging from surface transthoracic echocardiography and portable hand-held echocardiography, to contrast echocardiography, stress echocardiography, and TEE, among others. Numerous investigations have proven the worth of echocardiography, especially TEE, in the critically ill and injured patient, changing lives with the identification of obvious and subtle cardiothoracic diseases. Because this powerful imaging tool is immediately available and portable, crucial delays in diagnosis are not commonplace; rather than echocardiography, TEE, specifically, should be (and is in some institutions) the standard of care and management in assisting the intensivist in diagnosis of a variety of maladies. The effect of TEE technology is quite formidable, and numerous investigations have borne this out. The therapeutic effect of TEE ranges from 10% to 69%, with the majority of investigations falling into the 60% to 65% range. The diagnostic yield of TEE is far greater, approaching 78%. This article will detail the importance of echocardiography, its efficacy, and its high-yield imaging capability, particularly when compared with other imaging modalities, even transthoracic echocardiography.

Live/real time three-dimensional transthoracic echocardiographic assessment of left ventricular volumes, ejection fraction, and mass compared with magnetic resonance imaging

Due to reliance upon geometric assumptions and foreshortening issues, the traditionally utilized transthoracic two-dimensional echocardiography (2DTTE) has shown limitations in assessing left ventricular (LV) volume, mass, and function. Cardiac magnetic resonance imaging (MRI) has shown potential in accurately defining these LV characteristics. Recently, the emergence of live/real time three-dimensional (3D) TTE has demonstrated incremental value over 2DTTE and comparable value with MRI in assessing LV parameters. Here we report 58 consecutive patients with diverse cardiac disorders and clinical characteristics, referred for clinical MRI studies, who were evaluated by cardiac MRI and 3DTTE. Our results show good correlation between the two modalities.

Left ventricular mass in 169 healthy children and young adults assessed by three-dimensional echocardiography

The aims of this study were to establish normal values of left ventricular (LV) mass in children and young adults using three-dimensional echocardiography (3-DE) and to compare 3-DE LV mass estimates with those obtained by conventional echocardiographic methods. We studied 169 healthy subjects aged 2-27 years by digitized 3-D, two-dimensional (2-D), and M-mode echocardiography. 3-D echocardiography was performed by using rotational acquisition of planes at 18 degrees intervals from apical view with ECG gating and without respiratory gating. 3-DE gave smaller LV mass estimates than 2-DE and M-mode echocardiography (p < 0.001). Agreement analysis resulted in a bias of -9.3 +/- 36.5 g between 3-DE and 2-DE, and -18.5 +/- 47.9 g between 3-DE and M-mode. For the analysis, the subjects were divided into five groups according to body surface area (BSA): 0.5-0.75, 0.75-1.0, 1.0-1.25, 1.25-1.5, and greater than 1.5 m(2). LV mass/BSA by 3-DE was 45.6 (5.1), 54.3 (7.7), 55.2 (7.9), 58.8 (8.1), and 65.0 (9.9) g/m(2). LV mass/end diastolic volume (EDV) by 3-DE was 0.9 (0.1) g/ml in the BSA group of 0.5-0.75 m(2) and 1.0 (0.2) g/ml in the other BSA groups. LV mass increased linearly in relation to BSA, height, and body mass (r = 0.93, 0.90, and 0.92, respectively; p < 0.001 for all). The results showed a linear increase in LV mass, whereas LV mass/EDV ratio remained unchanged. However, LV mass estimates by 3-DE were lower than those obtained by 2-DE and M-mode echocardiography. The data obtained by 3-DE from 169 healthy subjects will serve as a reference for further studies in patients with various cardiac abnormalities.

Three-Dimensional Echocardiographic Evaluation of the Heart Chambers: Size, Function, and Mass

The major advantage of three-dimensional (3D) ultrasound imaging of the heart is the improvement in the accuracy of the echocardiographic evaluation of cardiac chamber volumes, which is achieved by eliminating the need for geometric modeling and the errors caused by foreshortened 2D views. In this article, we review the literature that has provided the scientific basis for the clinical use of 3D ultrasound imaging of the heart in the assessment of cardiac chamber size, function, and mass, and discuss its potential future applications.