Assessment of left ventricular function by real-time 3-dimensional echocardiography compared with conventional noninvasive methods

Effect of variable left ventricular ejection fraction assessed by equilibrium radionuclide angiocardiography using different software packages on the diagnosis of cardiotoxicity in patients with cancer

BACKGROUND

The equilibrium radionuclide angiocardiography (ERNA) scan is an established imaging modality for assessing left ventricular ejection fraction (LVEF) in oncology patients. This study aimed to explore the interchangeability of two commercially available software packages (MIM and JS) for LVEF measurement for a cancer-therapy-related cardiac dysfunction (CTRCD) diagnosis.

METHODS

This is a single-center retrospective study among 322 patients who underwent ERNA scans. A total of 582 scans were re-processed using MIM and JS for cross-sectional and longitudinal LVEF measurements.

RESULTS

The median LVEF for MIM and JS were 56% and 66%, respectively (P < 0.001). LVEF processed by JS was 9.91% higher than by MIM. In 87 patients with longitudinal ERNA scans, serial studies processed by MIM were classified as having CTRCD in a higher proportion than serial studies processed by JS (26.4% vs 11.4%, P = 0.020). There were no significant differences in intra- or inter-observer LVEF measurement variability (R = 0.99, P < 0.001).

CONCLUSIONS

Software packages for processing ERNA studies are not interchangeable; thus, reports of ERNA studies should include details on the post-processing software. Serial ERNA studies should be processed on the same software when feasible to avoid discrepancies in the diagnosis and management of CTRCD.

LVEF by Multigated Acquisition Scan Compared to Other Imaging Modalities in Cardio-Oncology: a Systematic Review

PURPOSE OF REVIEW

The prevalence of cancer therapy-related cardiac dysfunction (CTRCD) is increasing due to improved cancer survival. Serial monitoring of cardiac function is essential to detect CTRCD, guiding timely intervention strategies. Multigated radionuclide angiography (MUGA) has been the main screening tool using left ventricular ejection fraction (LVEF) to monitor cardiac dysfunction. However, transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR) may be more suitable for serial assessment. We aimed to assess the concordance between different non-radiating imaging modalities with MUGA to determine whether they can be used interchangeably.

RECENT FINDINGS

In order to identify relevant studies, a PubMed search was performed. We included cross-sectional studies comparing MUGA LVEF to that of 2D TTE, 3D TTE, and CMR. From 470 articles, 22 were selected, comprising 1017 patients in total. Among others, this included three 3D TTE, seven 2D harmonic TTE + contrast (2DHC), and seven CMR comparisons. The correlations and Bland-Altman limits of agreement varied for CMR but were stronger for 3D TTE and 2DHC. Our findings suggest that MUGA and CMR should not be used interchangeably whereas 3D TTE and 2DHC are appropriate alternatives following an initial MUGA scan. We propose a multimodality diagnostic imaging strategy for LVEF monitoring in patients undergoing cancer treatment.

HER2+ breast cancer treatment and cardiotoxicity: monitoring and management

BACKGROUND

Breast cancer is a leading cause of death for women worldwide, with incidence increasing in lower-income countries. For patients with human epidermal growth factor receptor-2-positive (HER2+) breast cancer, widespread availability of several agents targeting the HER2 receptor has resulted in survival gains over the past decades. However, improved survival has resulted in an increased need for management and mitigation of adverse events associated with anticancer therapy. Cardiac adverse events such as decreased ejection fraction and heart failure have been of particular concern in patients with HER2+ breast cancer. Anti-HER2 agents and chemotherapies (specifically anthracyclines, which are frequently used to treat HER2+ disease) have been associated with cardiotoxicity. As increasing numbers of patients are living longer due to more effective therapy, a better understanding of both monitoring and management of cardiotoxicity is urgently needed.

METHODS

A comprehensive review of the literature was conducted via PubMed in January 2018 for phase II and phase III trials of "trastuzumab", "lapatinib", "pertuzumab", "T-DM1", "neratinib", in "breast cancer". Literature was evaluated for content related to cardiac adverse events.

FINDINGS

We describe the incidence of and proposed mechanisms for the cardiotoxicity of available HER2-targeted therapies. We summarize current and emerging practices in the management of cardiotoxicity and provide guidance for routine patient care in real-world practice using illustrative patient scenarios.

CONCLUSIONS

The future of cardiotoxicity management in patients with HER2+ breast cancer is discussed, with a focus on novel techniques to improve cardiac outcomes, including new imaging modalities, biomarkers, interventional therapies, and ongoing trials.

Quantitative assessment of two- and three-dimensional transthoracic and two-dimensional transesophageal echocardiography, computed tomography, and magnetic resonance imaging in normal canine hearts

INTRODUCTION

The objective of the study was to evaluate the accuracy of two- and three-dimensional (2D, 3D) transthoracic echocardiography (TTE), 2D transesophageal echocardiography, and computed tomography angiography (CTA) compared with cardiac magnetic resonance imaging (CMR) in normal dogs and to assess repeatability of 2D and 3D TTE for the assessment of left ventricular (LV) and left atrial (LA) dimensions.

ANIMALS

The study was performed on six healthy dogs.

MATERIALS AND METHODS

Transthoracic echocardiography, transesophageal echocardiography, CTA, and CMR were performed on each dog. Right ventricular (RV) and LV volumes (in systole and diastole), ejection fraction (EF), and LA and right atrial (RA) volumes were assessed. Repeatability and intrarater and interrater measurements of variability were quantified by average coefficient of variation (CV) for 2D and 3D TTE.

RESULTS

No clinically relevant differences in LV volume were detected between CMR and all modalities. Importantly, 3D TTE had the lowest CV (6.45%), correlated with (r_s = 0.62, p = 0.01), and had the highest overlap in distribution with CMR (OVL >80%). Left ventricular EF and LA size via CTA compared best with CMR and RV and RA volumes were best estimated by 3D TTE. Assessment of LV and LA volumes via 3D TTE had moderate repeatability (15-21%) compared with LV M-mode measurements and 2D LA-to-aortic ratio (<10%), respectively. For LV size, interrater CV for 3D TTE (19.4%) was lower than 2D TTE (23.1%).

CONCLUSIONS

Measurements of LV, RV, and RA volumes via 3D TTE and LA volume and LV EF assessed by CTA compared best with CMR. Three-dimensional echocardiography had lower interrater and intrarater CV compared with 2D TTE.

Multimodality Imaging in Cardiooncology

Cardiotoxicity represents a rising problem influencing prognosis and quality of life of chemotherapy-treated patients. Anthracyclines and trastuzumab are the drugs most commonly associated with development of a cardiotoxic effect. Heart failure, myocardial ischemia, hypertension, myocarditis, and thrombosis are typical manifestation of cardiotoxicity by chemotherapeutic agents. Diagnosis and monitoring of cardiac side-effects of cancer treatment is of paramount importance. Echocardiography and nuclear medicine methods are widely used in clinical practice and left ventricular ejection fraction is the most important parameter to asses myocardial damage secondary to chemotherapy. However, left ventricular ejection decrease is a delayed phenomenon, occurring after a long stage of silent myocardial damage that classic imaging methods are not able to detect. New imaging techniques including three-dimensional echocardiography, speckle tracking echocardiography, and cardiac magnetic resonance have demonstrated high sensitivity in detecting the earliest alteration of left ventricular function associated with future development of chemotherapy-induced cardiomyopathy. Early diagnosis of cardiac involvement in cancer patients can allow for timely and adequate treatment management and the introduction of cardioprotective strategies.

Cardiac complications of chemotherapy: role of imaging

OPINION STATEMENT

New advances in cancer diagnosis and treatment have increased survival rates in patients with cancer. In parallel with this increase in the number of cancer survivors is an increasing prevalence of cardiac complications from cancer treatment. Chemotherapy-induced cardiac dysfunction is a major contributor to adverse morbidity and mortality rates in cancer patients. Evidence suggests that both clinical symptoms and the traditional left ventricular ejection fraction (LVEF) may lack sensitivity as measures of cardiotoxicity. The early identification of subclinical LV dysfunction is becoming increasingly important, as this may allow cancer patients and their physicians to make informed decisions about therapeutic options. The features of echocardiography make it a useful tool in the diagnosis and monitoring of cardiotoxicity. This review will examine the role of cardiac imaging in detecting cardiotoxicity, focusing primarily on the conventional and more recent echocardiographic approaches for assessing subclinical cardiotoxicity.

Cardiac toxicity of anticancer agents

Modern cancer therapies are highly effective in the treatment of various malignancies, but their use is limited by the potential for cardiotoxicity. The most frequent and typical clinical manifestation of cardiotoxicity is left ventricular dysfunction, induced not only by cytotoxic conventional cancer therapy like anthracyclines, but also by new antitumor targeted therapy such as trastuzumab. The current standard for monitoring cardiac function, based on periodic assessment of left ventricular ejection fraction detects cardiotoxicity only when a functional impairment has already occurred, precluding any chance of preventing its development. A novel approach, based on the use of cardiac biomarkers has emerged in the last decade, resulting in a cost-effective diagnostic tool for early, real-time identification, assessment and monitoring of cardiotoxicity. In particular, prophylactic treatment with enalapril in patients with an early increase in troponin after chemotherapy has been shown to be very effective in preventing left ventricular dysfunction and associated cardiac events. In patients developing cancer treatment induced-cardiomyopathy, complete left ventricular ejection fraction recovery and a reduction of cardiac events may be achieved only when left ventricular dysfunction is detected early after the end of cancer treatment and treatment with angiotensin-converting enzyme inhibitors, possibly in combination with beta-blockers, is promptly initiated.

Use of echocardiography to evaluate the cardiac effects of therapies used in cancer treatment: what do we know?

Cardiologists and oncologists today face the daunting challenge of identifying patients at risk for late-onset left ventricular (LV) systolic dysfunction from the use of various chemotherapeutic agents. Currently, the most widely used method in clinical practice for monitoring the potential of chemotherapy-induced cardiotoxicity is calculation of LV ejection fraction. The use of LV ejection fraction to determine whether to continue or discontinue the use of chemotherapeutic agents is limited, because decreases in LV ejection fraction frequently occur late and can be irreversible. These limitations have led to the exploration of diastolic function and newer modalities that assess myocardial mechanics to identify sensitive and specific variables that can predict the occurrence of late systolic function. The cancer therapies associated with cardiotoxicity are reviewed in this report. Additionally, the authors evaluate the role of present-day echocardiographic parameters, complementary noninvasive imaging modalities, and biomarkers in the prediction of cardiotoxicity. The authors address the evolving role of cardioprotective agents and potential therapies to prevent or reverse the progression of LV systolic dysfunction. Finally, they provide some ideas regarding future directions to enhance the knowledge of predicting late-onset LV systolic dysfunction secondary to cancer therapy.

Assessing the Cardiac Toxicity of Chemotherapeutic Agents: Role of Echocardiography

Advancements in cancer treatment have resulted in sufficient survival length for patients to experience treatment-related cardiac complications. In particular, chemotherapy-induced cardiac dysfunction significantly impacts morbidity and mortality rates in cancer patients. The presence of cardiotoxicity from chemotherapy has been traditionally assessed using clinical symptoms and decreases in left ventricular ejection fraction (LVEF). However, in this indication, LVEF lacks accuracy as a measure of subclinical cardiotoxicity and its prognostic value is controversial. There is an emphasis to identify subclinical and left ventricular dysfunction early, in order to allow cancer patients and their physicians to make informed decisions about therapeutic options. Echocardiography is a readily available noninvasive tool to measure cardiac function and plays a major role in the diagnosis of cardiotoxicity. This review focuses on the role of echocardiography in detecting cardiotoxicity, and will discuss conventional and more recent echocardiographic approaches for assessing subclinical cardiotoxicity.

Newest echocardiographic techniques for the detection of cardiotoxicity and heart failure during chemotherapy

Chemotherapy-induced cardiotoxicity has become a significant public health issue. Left ventricular ejection fraction is routinely used to monitor cardiotoxicity but fails to detect subtle alterations in cardiac function. Improvements in the measurement of left ventricular ejection fraction, physical or pharmacologic stressors, and novel cardiac functional indices may be useful in the detection of cardiotoxicity. The improvements in the detection and therapy of cancer have led to the emergence of chemotherapy-induced cardiotoxicity. New echocardiographic techniques may be useful in the detection of patients undergoing chemotherapy treatments who could benefit from alternative cancer treatments, therefore decreasing the incidence of cardiotoxicity.

Real time three-dimensional stress echocardiography: a new approach for assessing diastolic function

OBJECTIVE

To assess the feasibility of utilizing real time three-dimensional echocardiography (RT3DE) for assessment of diastolic function during stress.

METHODS

Rest and stress volumes were acquired in 24 patients and parameters of diastolic function-peak ventricular filling rate (PFR) and time to peak filling rate (TPFR)-were calculated.

RESULTS

Calculation of diastolic parameters was feasible in all patients. Resting PFR correlated with end-diastolic (EDV) and stroke volumes and inversely with TPFR (r = 0.53, 0.66, -0.5). With stress, PFR increased by 93% and TPFR decreased by 23% (P < 0.001). Stress PFR correlated with stress heart rate, EDV and stroke volume (r = 0.52, 0.50, 0.62) while TPFR correlated inversely with heart rate (r =-0.71). The change in PFR with stress correlated with the change in stroke volume (r = 0.42), while the change in TPFR correlated with the change in end-systolic volume (ESV) (r = 0.43) and inversely with the change in diastolic blood pressure (r =-0.41). Rest and stress PFR and TPFR are independent of age, gender and blood pressure and the change in PFR is independent of stress heart rate or blood pressure. E/E' correlated with stress TPFR (r = 0.72) and change in TPFR (r = 0.67) and inversely with change in PFR (r =-0.67).

CONCLUSIONS

RT3DE can assess diastolic function during stress by detecting changes in PFR and TPFR, independent of gender, age, and blood pressure. The changes in these parameters with stress are influenced by baseline filling pressures. Larger studies are required to validate the clinical significance of these observations.

Scintigraphic techniques for early detection of cancer treatment-induced cardiotoxicity

New antitumor agents have resulted in significant survival benefits for cancer patients. However, several agents may have serious cardiovascular side effects. Left ventricular ejection fraction measurement by (99m)Tc multigated radionuclide angiography is regarded as the gold standard to measure cardiotoxicity in adult patients. It identifies left ventricular dysfunction with high reproducibility and low interobserver variability. A decrease in left ventricular ejection fraction, however, is a relatively late manifestation of myocardial damage. Nuclear cardiologic techniques that visualize pathophysiologic processes at the tissue level could detect myocardial injury at an earlier stage. These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents. This review provides an overview of past, current, and promising newly developed radiopharmaceuticals and describes the role and recent advances of scintigraphic techniques to measure cardiotoxicity. Both first-order functional imaging techniques (visualizing mechanical [pump] function), such as (99m)Tc multigated radionuclide angiography and (99m)Tc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) are discussed. Third-order functional imaging techniques comprise (123)I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuronal PET, with its wide range of tracers; (111)In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; (99m)Tc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and (111)In-trastuzumab imaging, to study trastuzumab targeting to the myocardium. To define the prognostic importance and clinical value of each of these functional imaging techniques, prospective clinical trials are warranted.

Role of three-dimensional echocardiography in breast cancer: comparison with two-dimensional echocardiography, multiple-gated acquisition scans, and cardiac magnetic resonance imaging

PURPOSE

In patients with breast cancer, the administration of doxorubicin and trastuzumab is associated with an increased risk of cardiotoxicity. Although multiple-gated acquisition (MUGA) scans and two-dimensional transthoracic echocardiography (TTE) are conventional methods for baseline and serial assessment of left ventricular ejection fraction (LVEF) in these patients, little is known about the use of real-time three-dimensional TTE (RT3D TTE) in this clinical setting. The aim of this study was to assess the accuracy of MUGA, 2D TTE, and RT3D TTE for determining LVEF in comparison to cardiac magnetic resonance imaging (CMR).

METHODS

Between 2007 and 2009 inclusive, 50 female patients with human epidermal growth factor receptor 2-positive breast cancer received adjuvant trastuzumab after doxorubicin. Serial MUGA, 2D TTE, RT3D TTE, and CMR were performed at baseline, 6, and 12 months after the initiation of trastuzumab.

RESULTS

A comparison of left ventricular end diastolic volume (LVEDV) demonstrated a modest correlation between 2D TTE and CMR (r = 0.64 at baseline; r = 0.69 at 12 months, respectively). A comparison of LVEDV between RT3D TTE and CMR demonstrated a stronger correlation (r = 0.87 at baseline; r = 0.95 at 12 months, respectively). Although 2D TTE demonstrated a weak correlation with CMR for LVEF assessment (r = 0.31 at baseline, r = 0.42 at 12 months, respectively), both RT3D TTE and MUGA showed a strong correlation when compared with CMR (r = 0.91 at baseline; r = 0.90 at 12 months, respectively).

CONCLUSION

As compared with conventional MUGA, RT3D TTE is a feasible, accurate, and reproducible alternate imaging modality for the serial monitoring of LVEF in patients with breast cancer.

Quantitative three-dimensional wall motion analysis predicts ischemic region size and location

Stress echocardiography is an important screening test for coronary artery disease. Currently, cardiologists rely on visual analysis of left ventricular (LV) wall motion abnormalities, which is subjective and qualitative. We previously used finite-element models of the regionally ischemic left ventricle to develop a wall motion measure, 3DFS, for predicting ischemic region size and location from real-time 3D echocardiography (RT3DE). The purpose of this study was to validate these methods against regional blood flow measurements during regional ischemia and to compare the accuracy of our methods to the current state of the art, visual scoring by trained cardiologists. We acquired RT3DE images during 20 brief (<2 min) coronary occlusions in dogs and determined ischemic region size and location by microsphere-based measurement of regional perfusion. We identified regions of abnormal wall motion using 3DFS and by blinded visual scoring. 3DFS predicted ischemic region size well (correlation r (2) = 0.64 against microspheres, p < 0.0001), reducing error by more than half compared to visual scoring (8 +/- 9% vs. 19 +/- 14%, p < 0.05), while localizing the ischemic region with equal accuracy. We conclude that 3DFS is an objective, quantitative measure of wall motion that localizes acutely ischemic regions as accurately as wall motion scoring while providing superior quantification of ischemic region size.

Dose-dense adjuvant Doxorubicin and cyclophosphamide is not associated with frequent short-term changes in left ventricular ejection fraction

PURPOSE

Doxorubicin and cyclophosphamide (AC) every 3 weeks has been associated with frequent asymptomatic declines in left ventricular ejection fraction (LVEF). Dose-dense (dd) AC followed by paclitaxel (P) is superior to the same regimen given every third week. Herein, we report the early cardiac safety of three sequential studies of ddAC alone or with bevacizumab (B).

PATIENTS AND METHODS

Patients with HER2-positive breast cancer were treated on two trials: ddAC followed by P and trastuzumab (T) and ddAC followed by PT and lapatinib. Patients with HER2-normal breast cancer were treated with B and ddAC followed by B and nanoparticle albumin-bound P. Prospective LVEF measurement by multigated radionuclide angiography scan before and after every 2 week AC for 4 cycles and at month 6 from all three trials were aggregated to determine the early risks of cardiac dysfunction.

RESULTS

From January 2005 to May 2008, 245 patients were enrolled. The median age was 47 years (range, 27 to 75 years). Median LVEF pre-ddAC was 68% (range, 52% to 82%). LVEF post-ddAC was available in 241 patients (98%) and the median was unchanged at 68% (range, 47% to 81%). Per protocol no patients were ineligible for subsequent targeted biologic therapy based on LVEF decline post-ddAC. In addition, LVEF was available in 222 patients (92%) at 6 months, at which time the median LVEF was similar at 65% (range, 24% to 80%). Within 6 months of initiating chemotherapy, three patients (1.2%; 95% CI, 0.25% to 3.54%) developed CHF, all of whom received T.

CONCLUSION

Dose-dense AC with or without concurrent bevacizumab is not associated with frequent acute or short-term declines in LVEF.

Comparison of echocardiographic and cardiac magnetic resonance imaging measurements of functional single ventricular volumes, mass, and ejection fraction (from the Pediatric Heart Network Fontan Cross-Sectional Study)

Assessment of the size and function of a functional single ventricle (FSV) is a key element in the management of patients after the Fontan procedure. Measurement variability of ventricular mass, volume, and ejection fraction (EF) among observers by echocardiography and cardiac magnetic resonance imaging (CMR) and their reproducibility among readers in these patients have not been described. From the 546 patients enrolled in the Pediatric Heart Network Fontan Cross-Sectional Study (mean age 11.9 +/- 3.4 years), 100 echocardiograms and 50 CMR studies were assessed for measurement reproducibility; 124 subjects with paired studies were selected for comparison between modalities. Interobserver agreement for qualitative grading of ventricular function by echocardiography was modest for left ventricular (LV) morphology (kappa = 0.42) and weak for right ventricular (RV) morphology (kappa = 0.12). For quantitative assessment, high intraclass correlation coefficients were found for echocardiographic interobserver agreement (LV 0.87 to 0.92, RV 0.82 to 0.85) of systolic and diastolic volumes, respectively. In contrast, intraclass correlation coefficients for LV and RV mass were moderate (LV 0.78, RV 0.72). The corresponding intraclass correlation coefficients by CMR were high (LV 0.96, RV 0.85). Volumes by echocardiography averaged 70% of CMR values. Interobserver reproducibility for the EF was similar for the 2 modalities. Although the absolute mean difference between modalities for the EF was small (<2%), 95% limits of agreement were wide. In conclusion, agreement between observers of qualitative FSV function by echocardiography is modest. Measurements of FSV volume by 2-dimensional echocardiography underestimate CMR measurements, but their reproducibility is high. Echocardiographic and CMR measurements of FSV EF demonstrate similar interobserver reproducibility, whereas measurements of FSV mass and LV diastolic volume are more reproducible by CMR.

Accuracy of three-dimensional echocardiography in patients with prior anteroseptal myocardial infarction

BACKGROUND

Echocardiography is the most feasible modality for monitoring cardiac volume and function. However, conventional two-dimensional echocardiography (2DE) is frequently not accurate in measuring cardiac performance in cases of abnormal left ventricular wall motion, because of the geometric assumptions. Quantitative gated scintigraphy and magnetic resonance imaging are reliable modalities, but are expensive and not feasible for repetitive use. Real-time three-dimensional echocardiography (RT3DE) has been proved to be applicable in daily practice. The purpose of this study was to confirm the superiority of RT3DE to 2DE in assessing cardiac volume and function in patients with abnormal wall motion.

METHODS

The subjects were 41 patients with old anteroseptal myocardial infarction who underwent left ventricular volume and functional measurement by RT3DE, 2DE, and left ventriculography (LVG). End-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) from RT3DE and 2DE were measured and compared with results from LVG.

RESULTS

RT3DE correlated well with LVG in measurements of EDV, ESV, and EF (r = 0.815, 0.940, and 0.812, respectively; P < 0.001 each). Likewise, 2DE correlated with LVG, but underestimated left ventricular volume, particularly EDV (r = 0.652, 0.909, and 0.761, respectively; P < 0.001 each).

CONCLUSION

Values derived from RT3DE were closer to those from LVG than were values derived from 2DE. RT3DE provides important information on cardiac function in patients with prior anteroseptal myocardial infarction.

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.

Assessment of atrial septum morphology by live three-dimensional echocardiography

To evaluate the morphology of atrial septum by the live three-dimensional echocardiography (L3DE) and its value of clinical application, L3DE was performed in 62 subjects to observe the morphological characteristics and dynamic change of the overall anatomic structure of atrial septum. The study examined 49 patients with atrial septal defect (ASD), including 3 patients with atrial septal aneurysm, and 10 healthy subjects. ASD in the 35 patients was surgically confirmed. The maximal diameters of ASD were measured and the percentages of area change were calculated. The parameters derived from L3DE were compared with intraoperative measurements. The results showed that L3DE could directly and clearly display the morphological features of overall anatomic structure of normal atrial septum, repaired and artificially-occluded atrial septum, atrial septal aneurysm. The defect area in ASD patients changed significantly during cardiac cycle, which reached a maximum at end-systole and a minimum at end-diastole, with a mean change percentage of 46.6%, ranging from 14.8% to 73.4%. The sizes obtained from L3DE bore an excellent correlation with intraoperative findings (r=0.90). It is concluded that L3DE can clearly display the overall morphological features and dynamic change of atrial septum and measure the size of ASD area accurately, which is important in the decision to choose therapeutic protocols.

Real-Time Three-Dimensional Echocardiographic Acquisition and Quantification of Left Ventricular Indices in Children and Young Adults with Congenital Heart Disease: Comparison with Magnetic Resonance Imaging

BACKGROUND

Echocardiographic assessment of left ventricular (LV) contractility and dimensions is important in the management of patients with congenital heart disease. Conventional two-dimensional measures are limited because of volume or pressure-overloaded right ventricles that may distort the septal planes. Real-time three-dimensional echocardiography (RT3DE) has overcome these limitations; however, postprocessing image reconstruction and analysis are required. We compared LV indices calculated by new online RT3DE software with those obtained by magnetic resonance imaging (MRI) in patients with congenital heart disease.

METHODS

Twelve patients (ages 1-33 years, median age = 15.9 years) with congenital heart disease underwent RT3DE and cardiac MRI. End-diastolic and end-systolic LV volumes, stroke volume, ejection fraction, and mass were calculated online using biplane method-of-discs and semiautomated border detection echocardiographic techniques.

RESULTS

All RT3DE volumes correlated strongly with MRI (r = 0.93-0.99, P < .001). Ejection fraction had a lower correlation (r = 0.69, P = .013). There was no significant underestimation or overestimation of MRI values by RT3DE. Both biplane method-of-discs and semiautomated border detection echocardiographic techniques had excellent volume correlation (r = 0.94-0.99, P < .001). Interobserver variability was 7%.

CONCLUSIONS

Combined RT3DE acquisition and analysis machines can accurately assess the LV in patients with congenital heart disease, thus impacting clinical management and perhaps obviating the need for MRI in some cases.

Feasibility and clinical impact of live three-dimensional echocardiography in the management of congenital heart disease

BACKGROUND

Precise assessment of congenital heart lesions requires inferential evaluation from multiple two-dimensional echocardiographic images (2DE). The aim of our study was to assess the usefulness of transthoracic live three-dimensional echocardiography (3DE) in the evaluation of congenital heart disease.

METHODS

Eighty-two patients (from 4 months to 31 years, mean age 12 +/- 7.5, 38 males and 44 females), known to have congenital heart lesions, prospectively underwent both 2DE and 3DE. Conventional data acquisition by 2DE and "full volume" 3DE acquisition (apical four chambers, parasternal long and short axes, subcostal windows) were carried out by two independent and blinded operators. Data derived from 3DE were compared to 2DE, and 3DE results were graded into three categories: (A) new findings not seen on 2D echo studies, but not critical to therapeutic decision making; (B) additional anatomic information useful in therapeutic decision making; and (C) information equivalent to 2D echo studies.

RESULTS

Two out of 82 patients (2%) were excluded because of suboptimal 3DE images. In comparison with 2DE studies, 3DE was graded A in 23 patients (29%), B in 28 patients (35%), and C in 29 patients (36%). In the patients with group B results, atrial and ventricular septal defects, endocardial cushion defects, and l-transposition of great vessels were the most represented pathologies in which 3DE aided medical or surgical therapeutic options. While the new findings in group A did not influence therapy, they defined the whole spectrum of abnormalities in those patients. In patients who fell under group C results, 3DE provided a direct realistic display of the pathology detected by 2DE.

CONCLUSIONS

Our study demonstrates that live 3DE, easily performed at the bedside, provides incremental information on patients with a variety of congenital heart lesions. In the clinical scenario, it clarifies the pathology in all its dimensions, particularly in complex lesions with the incremental information having impact on therapeutic decision making.

Live 3D Echocardiography: A Replacement for Traditional 2D Echocardiography?

OBJECTIVE

We describe the development of real-time 3D imaging and review the previously used versions of 3D echocardiography so that the reader will appreciate why current developments truly do represent a quantum leap in the technology.

CONCLUSION

Three-dimensional echocardiography has now been shown to have several advantages over 2D echocardiography, particularly for volume measurements, visualization of septal defects, and whole-valve evaluation. Given these data, it is clear that 3D echocardiography is here to stay and soon will become part of routine echocardiographic examinations.

Registration-assisted segmentation of real-time 3-D echocardiographic data using deformable models

Real-time three-dimensional (3-D) echocardiography is a new imaging modality that presents the unique opportunity to visualize the complex 3-D shape and motion of the left ventricle (LV) in vivo and to measure the associated global and local function parameters. To take advantage of this opportunity in routine clinical practice, automatic segmentation of the LV in the 3-D echocardiographic data, usually hundreds of megabytes large, is essential. We report a new segmentation algorithm for this task. Our algorithm has two distinct stages, initialization of a deformable model and its refinement, which are connected by a dual "voxel + wiremesh" template. In the first stage, mutual-information-based registration of the voxel template with the image to be segmented helps initialize the wiremesh template. In the second stage, the wiremesh is refined iteratively under the influence of external and internal forces. The internal forces have been customized to preserve the nonsymmetric shape of the wiremesh template in the absence of external forces, defined using the gradient vector flow approach. The algorithm was validated against expert-defined segmentation and demonstrated acceptable accuracy. Our segmentation algorithm is fully automatic and has the potential to be used clinically together with real-time 3-D echocardiography for improved cardiovascular disease diagnosis.

Segmentation of real-time three-dimensional ultrasound for quantification of ventricular function: a clinical study on right and left ventricles

Among screening modalities, echocardiography is the fastest, least expensive and least invasive method for imaging the heart. A new generation of three-dimensional (3-D) ultrasound (US) technology has been developed with real-time 3-D (RT3-D) matrix phased-array transducers. These transducers allow interactive 3-D visualization of cardiac anatomy and fast ventricular volume estimation without tomographic interpolation as required with earlier 3-D US acquisition systems. However, real-time acquisition speed is performed at the cost of decreasing spatial resolution, leading to echocardiographic data with poor definition of anatomical structures and high levels of speckle noise. The poor quality of the US signal has limited the acceptance of RT3-D US technology in clinical practice, despite the wealth of information acquired by this system, far greater than with any other existing echocardiography screening modality. We present, in this work, a clinical study for segmentation of right and left ventricular volumes using RT3-D US. A preprocessing of the volumetric data sets was performed using spatiotemporal brushlet denoising, as presented in previous articles Two deformable-model segmentation methods were implemented in 2-D using a parametric formulation and in 3-D using an implicit formulation with a level set implementation for extraction of endocardial surfaces on denoised RT3-D US data. A complete and rigorous validation of the segmentation methods was carried out for quantification of left and right ventricular volumes and ejection fraction, including comparison of measurements with cardiac magnetic resonance imaging as the reference. Results for volume and ejection fraction measurements report good performance of quantification of cardiac function on RT3-D data compared with magnetic resonance imaging with better performance of semiautomatic segmentation methods than with manual tracing on the US data.

Non-invasive assessment of myocardial ischaemia using new real-time three-dimensional dobutamine stress echocardiography: comparison with conventional two-dimensional methods

AIMS

Although two-dimensional-dobutamine stress echocardiography (2D-DSE) is useful for the diagnosis of myocardial ischaemia, it requires the acquisition of multiple cross-sections at each stage. The introduction of new real-time three-dimensional echocardiography (RT3DE) offers rapid acquisition and 3D display of the entire left ventricle (LV). The purpose was to evaluate real-time three-dimensional-dobutamine stress echocardiography (RT3D-DSE) for the diagnosis of ischaemia using exercise (201)Tl single-photon emission computed tomography (SPECT) as the reference standard, in comparison with 2D-DSE.

METHODS AND RESULTS

We performed DSE in 56 consecutive patients who had undergone SPECT because of suspected ischaemia. 3D images by RT3DE were acquired from the apical window after the acquisition of cross-sectional images at every stage of 2D-DSE. Wall motion analysis in RT3DE was performed from anatomical images by cropping the acquired full volume data sets. Mean scanning time for adequate image acquisition at peak stress by RT3D-DSE was shorter than that by 2D-DSE (29+/-4 vs. 68+/-6 s, P<0.0001). RT3DE provided adequate images at success rate of 92% at rest and 89% at peak stress, whereas two-dimensional echocardiography did at 94 and 90%, respectively. The sensitivity, specificity, and accuracy of RT3D-DSE for the detection of coronary artery disease are 86, 80, and 82%, respectively. Those of 2D-DSE are 86, 83, and 84%, respectively. There were no significant differences in the sensitivity, specificity, and accuracy between these two methods (P=1.000).

CONCLUSION

RT3D-DSE offers rapid and simple acquisition of the entire LV wall motion and provides feasible and accurate assessment of myocardial ischaemia.

Accuracy of measurement of left ventricular volume and ejection fraction by new real-time three-dimensional echocardiography in patients with wall motion abnormalities secondary to myocardial infarction

Three-dimensional echocardiography is an ideal tool for the measurement of left ventricular (LV) volume because no geometric assumptions about LV shape are needed. The introduction of new real-time 3-dimensional echocardiography (RT3DE) has allowed rapid acquisition of a 3-dimensional dataset with good image quality. The purpose of this study was to examine the accuracy of RT3DE for the measurement of LV volume and ejection fraction in patients with wall motion abnormalities by using quantitative gated single-photon emission computed tomography (QGSPECT) as a reference standard. The study population consisted of 25 consecutive patients with wall motion abnormalities who underwent LV volume measurement by 2-dimensional echocardiography and by QGSPECT. LV volume and ejection fraction by RT3DE were measured offline by using the average rotation method. In 23 of 25 patients (92%), it was possible to measure 3-dimensional volume with RT3DE. RT3DE correlated well with QGSPECT in the measurement of end-diastolic volume and end-systolic volume (r = 0.97, mean difference 3.4 ml; r = 0.98, mean difference 2.0 ml, respectively), 2-dimensional echocardiography also correlated with QGSPECT but underestimated LV volume (r = 0.98, mean difference 21.1 ml; r = 0.98, mean difference 15.6 ml, respectively). Ejection fraction obtained by RT3DE had better agreement with that obtained by QGSPECT than that obtained by 2-dimensional echocardiography (r = 0.92, mean difference -0.2%; r = 0.89, mean difference -2.7%, respectively). RT3DE allows convenient and accurate estimation of LV volume and ejection fraction in patients with wall motion abnormalities.

Determination of Asymmetric Cavity Volumes Using Real-Time Three-Dimensional Echocardiography: An In Vitro Balloon Model Study

OBJECTIVES

We designed a new in vitro model to test the accuracy and reproducibility of real-time three-dimensional (RT3D) ultrasound imaging for determining a variety of asymmetric cavity volumes with aneurysm.

METHODS

Fifteen individual balloon models mimicking ventricular aneurysm were filled with water (170-322.5 ml) without air bubbles and kept in a compressor pump. Compression of the models produced only a change in shape of the balloon and no change in volume. The models were scanned with RT3D echocardiography (RT3DE) and the images recorded on an optical disk. Volumes were measured off line in two phases; maximal compression, where there was maximal change in shape and nil compression, where there was minimal or no change in shape. Volumes were measured by manual tracing technique of the inner border of B-scan images and compared with the drained volume of water from the balloon.

RESULTS

There was a high correlation between the drained volume and measured volume at maximal compression (equivalent to end-systole, r = 0.99, y = 0.99x + 3.69, SEE = 6.5 ml), between the drained volume and measured volume at nil compression (equivalent to end-diastole, r = 0.99, y = 0.94x + 12.07, SEE = 5.9 ml), and between volumes measured at maximal and nil compressions (r = 0.99, y = 0.94x + 10.55, SEE = 4.6 ml).

CONCLUSION

The results of this experiment show that RT3DE can accurately measure the volumes of a variety of asymmetric ventricular cavities.

Validation of a volumic reconstruction in 4-d echocardiography and gated SPECT using a dynamic cardiac phantom

A dynamic cardiac phantom was used as a reference to compare the volumes reconstructed with 4-D echocardiography and gated single-photon emission computed tomography (SPECT). 4-D echocardiography used a new prototype of rotating scan head to acquire ultrasound (US) images during a cardiac cycle, associated with a new protocol (left ventricular 4-D or LV 4-D) to reconstruct the volume deformations of the heart as a function of time. Gated SPECT data were acquired with a standard single-head gamma camera, and the reconstructions were carried out using the Mirage software released by Segami. The influences of different LV 4-D parameters were tested and analyzed. End-diastolic volume, end-systolic volume, and ejection fraction were measured using both LV 4-D and gated SPECT. Results obtained showed a straight correlation between the two examinations. The agreement confirmed the relevance of the comparisons. This study is an initial step before conducting clinical trials to exhaustively compare the two modalities.

Automated quantification of left ventricular function by the automated contour tracking method

The automated contour tracking (ACT) method has been developed for the automated measurement of area volume using the energy minimization method without tracing a region of interest. The purpose of this study was to compare the ACT method and left ventriculography (LVG) for the measurement of left ventricular (LV) function in the clinical setting. An apical four-chamber view was visualized by two-dimensional echocardiography and recorded for off-line analysis in 14 patients with high-quality images who underwent LVG. The ACT method automatically traces the endocardial border from the recorded images and calculates LV volumes (end-diastole and end-systole) and ejection fraction (EF). Both ACT and LVG were compared by linear regression analysis for the measurement of EF. EF determined by the ACT method agreed well with that by LVG (r = 0.96, y = 0.94x + 4.6, standard error of the estimate = 3.9%). The mean difference between the ACT and LVG was -1.4%+/- 7.3%. In conclusion, the ACT method is reliable for noninvasive estimation of EF in high-quality images. This suggests that this new technique may be useful in the automated quantification of LV function.

Quantification of left ventricular volumes and ejection fraction using freehand transthoracic three-dimensional echocardiography: comparison with magnetic resonance imaging

OBJECTIVES

Our aim was to validate 3-dimensional echocardiography (3DE) for assessment of left ventricular (LV) end-diastolic volume, end-systolic volume (ESV), stroke volume, and ejection fraction (EF) using the freehand-acquisition method. Furthermore, LV volumes by breath hold-versus free breathing-3DE acquisition were assessed and compared with magnetic resonance imaging (MRI).

METHODS

From the apical position, a fan-like 3DE image was acquired during free breathing and another, thereafter, during breath hold. In 27 patients, 28 breath hold- and 24 free breathing-3DE images were acquired. A total of 17 patients underwent both MRI and 3DE. MRI contours were traced along the outer endocardial contour, including trabeculae, and along the inner endocardial contour, excluding trabeculae, from the LV volume.

RESULTS

All 28 (100%) breath hold- and 86% of free breathing-3DE acquisitions could be analyzed. Intraobserver variation (percentual bias +/- 2 SD) of end-diastolic volume, ESV, stroke volume, and EF for breath-hold 3DE was, respectively, 0.3 +/- 10.2%, 0.3 +/- 14.6%, 0.1 +/- 18.4%, and -0.1 +/- 5.8%. For free-breathing 3DE, findings were similar. A significantly better interobserver variability, however, was observed for breath-hold 3DE for ESV and EF. Comparison of breath-hold 3DE with MRI inner contour showed for end-diastolic volume, ESV, stroke volume, and EF, a percentual bias (+/- 2 SD) of, respectively, -13.5 +/- 26.9%, -17.7 +/- 47.8%, -10.6 +/- 43.6%, and -1.8 +/- 11.6%. Compared with the MRI outer contour, a significantly greater difference was observed, except for EF.

CONCLUSIONS

3DE using the freehand method is fast and highly reproducible for (serial) LV volume and EF measurement, and, hence, ideally suited for clinical decision making and trials. Breath-hold 3DE is superior to free-breathing 3DE regarding image quality and reproducibility. Compared with MRI, 3DE underestimates LV volumes, but not EF, which is mainly explained by differences in endocardial contour tracing by MRI (outer contour) and 3DE (inner contour) of the trabecularized endocardium. Underestimation is reduced when breath-hold 3DE is compared with inner contour analysis of the MRI dataset.