What is the optimal clinical technique for measurement of left ventricular volume after myocardial infarction? A comparative study of 3-dimensional echocardiography, single photon emission computed tomography, and cardiac magnetic resonance imaging

Comparison of the dyssynchrony parameters recorded with gated SPECT in ischemic cardiomyopathy according to their repeatability at rest and to their ability to detect a synchrony reserve under dobutamine infusion

BACKGROUND

This study aimed to determine whether the repeatability of dyssynchrony assessment using gated myocardial perfusion SPECT (GSPECT) allows the detection of synchrony reserve during low-dose dobutamine infusion.

METHODS AND RESULTS

Sixty-one patients with ischemic cardiomyopathy and LV ejection fraction < 50% were prospectively included in 10 centers. Each patient underwent two consecutive rest GSPECT with 99mTc-labeled tracer (either tetrofosmin or sestamibi) to assess the repeatability of LV function and dyssynchrony parameters, followed by a GSECT acquisition during low-dose dobutamine infusion. LV dyssynchrony was assessed using QGS software through histogram bandwidth (BW), standard deviation of the phase (SD), and entropy. Repeatability was assessed with Lin's concordance correlation coefficient (CCC). Entropy showed a higher CCC (0.80) compared to BW (0.68) and SD (0.75). On average, dobutamine infusion yielded to improve both BW (P = .049) and entropy (P = .04) although significant improvements, setting outside the 95% confidence interval of the repeatability analysis, were documented in only 6 and 4 patients for BW and entropy, respectively.

CONCLUSIONS

A synchrony reserve may be documented in patients with ischemic cardiomyopathy through the recording of BW and entropy with low-dose dobutamine GSPECT, with the additional advantage of a higher repeatability for entropy.

Measurement of Ejection Fraction by Cardiac Magnetic Resonance Imaging and Echocardiography to Monitor Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a standard treatment option for breast cancer, lymphoma, and leukemia, but its benefits are limited by its potential for cardiotoxicity. The primary objective of this study was to compare cardiac magnetic resonance imaging (CMRI) versus echocardiography (ECHO) to detect a reduction in left ventricular ejection function, suggestive of doxorubicin cardiotoxicity. We studied eligible patients who were 18 years or older, who had breast cancer or lymphoma, and who were offered treatment with doxorubicin with curative intent dosing of 240 to 300 mg/m ² body surface area between March 1, 2009 and October 31, 2013. Patients underwent baseline CMRI and ECHO. Both imaging studies were repeated after four cycles of treatment. Ejection fraction (EF) calculated by both methods was compared and analyzed with the inferential statistical Student's t test. Twenty-eight eligible patients were enrolled. Two patients stopped participating in the study before undergoing baseline CMRI; 26 patients underwent baseline ECHO and CMRI. Eight of those 26 patients declined posttreatment studies, so the final study population was 18 patients. There was a significant difference in EF pre- and posttreatment in the CMRI group ( p  = 0.009) versus the ECHO group that showed no significant differences in EF ( p  = NS). It appears that CMRI is superior to ECHO for detecting doxorubicin-induced reductions in cardiac systolic function. However, ECHO is less expensive and more convenient for patients because of its noninvasive character and bedside practicality. A larger study is needed to confirm these findings.

Is 3D Dobutamine stress echocardiography ready for prime time? Diagnostic and prognostic implications

Aims

Compare the diagnostic accuracy and prognostic value of echo contrast enhanced 2D and 3D Dobutamine stress echocardiography (DSE).

Methods and results

We included 718 patients indicated for DSE. All had standard 2D, and contrast enhanced left ventricular opacification (LVO) for 2D and 3D acquisitions at rest and peak stress. Chi-square test was done to assess relationship between DSE result and early revascularization. Kaplan–Meier plots with Logistic regression analysis predicted late major adverse cardiovascular events (MACE) at a maximum follow-up of 84 months. The mean age was 63 ± 13 years (61% males) and follow-up was obtained in 692/718 (96.4%) patients. Only 32% had excellent baseline image quality. The DSE was abnormal in 19.4% patients on 2D, in 17.1% on 2D-LVO and in 19.1% on 3D-LVO. Early revascularization was performed in, respectively, 32.8%, 45.8%, and in 48.5% of stress-positive 2D, 2D-LVO, and 3D-LVO studies. After excluding the 66 patients receiving early revascularization 68/626 (10.9%) had MACE at a maximum follow-up of 84 months. Kaplan–Meier plots showed that stress-positive 2D-LVO and 3D-LVO studies not receiving early revascularization when assessed separately and combined had significantly worse outcomes for MACE compared with stress-negative patients (OR 3.69; 95% CI: 1.54–8.87; P = 0.011, OR 4.54; 95% CI: 1.72–12.93; P = 0.008, and OR 7.07, 95% CI: 1.62–25.16; P = 0.001, respectively).

Conclusion

Combined use of 2D- and 3D-LVO DSE is ready for prime time considering the feasibility, improved diagnostic accuracy and prognostic value.

Comparison of Left Ventricular Volumes Measured by 3DE, SPECT and CMR

BACKGROUND

Information regarding left ventricular (LV) volume and left ventricular ejection fraction (LVEF) has major diagnostic and prognostic value when assessing patients after ST-elevation myocardial infarction (STEMI). We aimed to investigate the agreement between measurement of LV volumes and LVEF by three-dimensional echocardiography (3DE), single-photon emission computed tomography (SPECT) and cardiac magnetic resonance (CMR) imaging in patients in a stable phase after STEMI.

METHODS

Fifteen patients underwent examinations by 3DE, SPECT and CMR three months after STEMI.

RESULTS

There was a significant bias in end-diastolic volume (EDV) measured by 3DE (–64 mL, p < 0.001) and SPECT (–55 mL, p < 0.001) compared with that measured by CMR. This was also the case for end-systolic volume (ESV) measured by 3DE (–36 mL, p < 0.001) and SPECT (–28 mL, p < 0.001). No significant differences were found between 3DE and SPECT for EDV or ESV. However, LVEF did not differ between the three methods. The agreement between all three methods was moderate (intra-class correlation coefficient [ICC] = 0.44) for LV volume and good for LVEF (ICC = 0.72).

CONCLUSIONS

LV volumes assessed by 3DE did not differ from SPECT, and despite larger LV volumes by CMR, measurements of LVEF showed good agreement between all three methods.

Current Clinical Applications of Three-Dimensional Echocardiography: When the Technique Makes the Difference

Advances in ultrasound, computer, and electronics technology have permitted three-dimensional echocardiography (3DE) to become a clinically viable imaging modality, with significant impact on patient diagnosis, management, and outcome. Thanks to the inception of a fully sampled matrix transducer for transthoracic and transesophageal probes, 3DE now offers much faster and easier data acquisition, immediate display of anatomy, and the possibility of online quantitative analysis of cardiac chambers and heart valves. The clinical use of transthoracic 3DE has been primarily focused, albeit not exclusively, on the assessment of cardiac chamber volumes and function. Transesophageal 3DE has been applied mostly for assessing heart valve anatomy and function. The advantages of using 3DE to measure cardiac chamber volumes derive from the lack of geometric assumptions about their shape and the avoidance of the apical view foreshortening, which are the main shortcomings of volume calculations from two-dimensional echocardiographic views. Moreover, 3DE offers a unique realistic en face display of heart valves, congenital defects, and surrounding structures allowing a better appreciation of the dynamic functional anatomy of cardiac abnormalities in vivo. Offline quantitation of 3DE data sets has made significant contributions to our mechanistic understanding of normal and diseased heart valves, as well as of their alterations induced by surgical or interventional procedures. As reparative cardiac surgery and transcatheter procedures become more and more popular for treating structural heart disease, transesophageal 3DE has expanded its role as the premier technique for procedure planning, intra-procedural guidance, as well as for checking device function and potential complications after the procedure.

Evaluation of inter-departmental variability of ejection fraction and cardiac volumes in myocardial perfusion scintigraphy using simulated data

BACKGROUND

Myocardial perfusion scintigraphy (MPS) is a clinically useful noninvasive imaging modality for diagnosing patients with suspected coronary artery disease. By utilizing gated MPS, the end diastolic volume (EDV) and end systolic volume (ESV) can be measured and the ejection fraction (EF) calculated, which gives incremental prognostic value compared with assessment of perfusion only. The aim of this study was to evaluate the inter-departmental variability of EF, ESV, and EDV during gated MPS in Sweden.

METHODS

Seventeen departments were included in the study. The SIMIND Monte Carlo (MC) program together with the XCAT phantom was used to simulate three patient cases with different EDV, ESV, and EF. Individual simulations were performed for each department, corresponding to their specific method of performing MPS. Images were then sent to each department and were evaluated according to clinical routine. EDV, ESV, and EF were reported back.

RESULTS

There was a large underestimation of EDV and ESV for all three cases. Mean underestimation for EDV varied between 26% and 52% and for ESV between 15% and 60%. EF was more accurately measured, but mean bias still varied between an underestimation of 24% to an overestimation of 14%. In general, the intra-departmental variability for EDV, ESV, and EF was small, whereas inter-departmental variability was larger.

CONCLUSIONS

Left ventricular volumes were generally underestimated, whereas EF was more accurately estimated. There was, however, large inter-departmental variability.

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.

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.

Performance of 3-dimensional echocardiography in measuring left ventricular volumes and ejection fraction: a systematic review and meta-analysis

OBJECTIVES

The primary aim of this systematic review is to objectively evaluate the test performance characteristics of three-dimensional echocardiography (3DE) in measuring left ventricular (LV) volumes and ejection fraction (EF).

BACKGROUND

Despite its growing use in clinical laboratories, the accuracy of 3DE has not been studied on a large scale. It is unclear if this technology offers an advantage over traditional two-dimensional (2D) methods.

METHODS

We searched for studies that compared LV volumes and EF measured by 3DE and cardiac magnetic resonance (CMR) imaging. A subset of those also compared standard 2D methods with CMR. We used meta-analyses to determine the overall bias and limits of agreement of LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF measured by 3DE and 2D echocardiography (2DE).

RESULTS

Twenty-three studies (1,638 echocardiograms) were included. The pooled biases ± 2 SDs for 3DE were -19.1 ± 34.2 ml, -10.1 ± 29.7 ml, and - 0.6 ± 11.8% for EDV, ESV, and EF, respectively. Nine studies also included data from 2DE, where the pooled biases were -48.2 ± 55.9 ml, -27.7 ± 45.7 ml, and 0.1 ± 13.9% for EDV, ESV, and EF, respectively. In this subset, the difference in bias between 3DE and 2D volumes was statistically significant (p = 0.01 for both EDV and ESV). The difference in variance was statistically significant (p < 0.001) for all 3 measurements.

CONCLUSIONS

Three-dimensional echocardiography underestimates volumes and has wide limits of agreement, but compared with traditional 2D methods in these carefully performed studies, 3DE is more accurate for volumes and more precise in all 3 measurements.

Agreement between cardiac outputs by four-dimensional echocardiography and thermodilution method is poor

OBJECTIVE

The objective of the study was to determine the agreement of cardiac output (CO) measured by four-dimensional echocardiography (4D echo) to simultaneously obtain CO from pulmonary artery catheter (PAC) using thermodilution technique.

MATERIALS AND METHODS

Sixty-three comparable readings from 27 patients scheduled for elective coronary artery bypass were included. All echocardiographic measurements were obtained by one experienced echocardiographer. All echo images were analyzed independently and blinded from PAC-obtained measurements. Analysis was primarily done by Bland and Altman plot. The collected data were further controlled for interobserver bias and image quality.

RESULTS

Differences in CO measurements increased with higher CO, hence values were logarithmically transformed. On the logaritmic scale, the 4D echo underestimated CO by 0.37 l/min compared with PAC, indicating that PAC measurements were 1.45 times higher than the 4D echo (95% confidence interval 1.32-1.52) and limits of agreement 0.97-2.14). The interobserver bias of 4D echo measurement analysis was 0.29 l/min (95% confidence interval 0.16-0.42) and limits of agreement -0.8-1.38). No difference was seen in image quality between comparisons with good agreement compared with comparisons with poor agreement.

CONCLUSION

The agreement between COs by 4D echo and standard PAC thermodilution technique was poor. 4D echo underestimates CO as compared with PAC. This is most likely caused by the analysis software or low frame rate inherent to the technique.

Real time 3D echocardiography (RT3D) for assessment of ventricular and vascular function in hypertensive and heart failure patients

Background

Cardiac and systemic hemodynamics have been historically in the domain of invasive cardiology, but recent advances in real-time 3-Dimensional echocardiography (RT3D echo) provide a reliable measurement of ventricular volumes, allowing to measure a set of hemodynamic parameters previously difficult or impossible to obtain with standard 2D echo.

Aim

To assess the feasibility of a comprehensive hemodynamic study with RT-3D echo.

Methods

We enrolled 136 patients referred for routine echocardiography: 44 normal (N), 57 hypertensive (HYP), and 35 systolic heart failure patients (HF). All patients underwent standard 2D echo examination followed by RT3D echo examination, including measurement of left ventricular (LV) end-diastolic and end-systolic volumes and derived assessment of LV elastance (an index of LV contractility), arterial elastance (characterizing the distal impedance of the arterial system downstream of the aortic valve); ventricular-arterial coupling (a central determinant of net cardiovascular performance); systemic vascular resistances. Blood pressure was derived from cuff sphygmomanometer and heart rate from ECG.

Results

A complete 2D echo was performed in all 136 patients. 3D echo examination was obtained in 130 patients (feasibility = 95 %). Standard 2D echo examination was completed in 14.8 ± 2.2 min. Acquisition of 3D images required an average time of 5 ± 0.9 min (range 3.5-7.5 min) and image analysis was completed in 10.1 ± 2.8 min (range 6–12 min) per patient. Compared to N and HYP, HF patients showed reduced LV elastance (1.7 ± 1.5 mmHg mL^-1 m^-2, p <0.001 vs N = 3.8 ± 1.3 and HYP = 3.8 ± 1.3) and ventricular-arterial coupling (0.6 ± 0.5, p < 0.01 vs N = 1.4 ± 0.4 and HYP = 1.2 ± 0.4). Systemic vascular resistances were highest in HYP (2736 ± 720, p < .01 vs N = 1980 ± 432 and vs HF = 1855 ± 636 dyne*s/cm⁵). The LV elastance was related to EF (r = 0.73, p < 0.01) and arterial pressure was moderately related to vascular elastance (r = 0.54, p < 0.01). The ventricular-arterial coupling was unrelated to systemic vascular resistances (r = −0.04, p NS).

Conclusion

RT-3D echo allows a non invasive, comprehensive assessment of cardiac and systemic hemodynamics, offering insight access to key variables – such as increased systemic vascular resistances in hypertensives and reduced ventricular-arterial coupling in heart failure patients.

Three-dimensional transesophageal echocardiography for perioperative right ventricular assessment

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Development and validation of a new automatic algorithm for quantification of left ventricular volumes and function in gated myocardial perfusion SPECT using cardiac magnetic resonance as reference standard

BACKGROUND

By gating image acquisition in myocardial perfusion SPECT (MPS) to ECG, left ventricular (LV) volumes and function can be determined. Several previous studies have shown that existing MPS software packages underestimate LV volumes compared to cardiac magnetic resonance (CMR). The aim of this study was therefore to develop a new LV segmentation algorithm for gated MPS using CMR as reference standard.

METHODS AND RESULTS

A total of 126 patients with suspected coronary artery disease, who underwent both gated MPS and CMR were retrospectively included. The proposed LV segmentation algorithm (Segment) was trained in 26 patients, and tested in 100 patients in comparison to four commercially available MPS software packages (QGS, MyoMetrix, ECTb, and Exini) using CMR as reference standard. Mean bias ± SD between MPS and CMR was for EDV -5% ± 12%, -43% ± 8%, -40% ± 8%, -42% ± 9%, -32% ± 7%, for ESV 0% ± 17%, -41% ± 16%, -34% ± 15%, -54% ± 13%, -41% ± 10%, for EF -2% ± 13%, -1% ± 14%, -7% ± 15%, 17% ± 16%, 10% ± 17% for Segment, QGS, MyoMetrix, ECTb, and Exini, respectively, and for LVM 3% ± 18%, 33% ± 25%, 37% ± 24% for Segment, QGS, and ECTb, respectively. Correlation between MPS by Segment and CMR were for EDV R (2) = 0.89, for ESV R (2) = 0.92, for EF R (2) = 0.69, and for LVM R (2) = 0.72, with no difference compared to the correlation between the other MPS software packages and CMR (EDV R (2) = 0.86-0.92, ESV R (2) = 0.91-0.93, EF R (2) = 0.64-0.65, and LVM R (2) = 0.68-0.70).

CONCLUSION

The Segment software quantifies LV volumes and EF by MPS with similar correlation and a low bias compared to other MPS software packages, using CMR as reference standard. Hence, the Segment software shows potential to provide clinically relevant volumes and functional values from MPS.

Three-dimensional echocardiography for left ventricular quantification: fundamental validation and clinical applications

One of the earliest applications of clinical echocardiography is evaluation of left ventricular (LV) function and size. Accurate, reproducible and quantitative evaluation of LV function and size is vital for diagnosis, treatment and prediction of prognosis of heart disease. Early three-dimensional (3D) echocardiographic techniques showed better reproducibility than two-dimensional (2D) echocardiography and narrower limits of agreement for assessment of LV function and size in comparison to reference methods, mostly cardiac magnetic resonance (CMR) imaging, but acquisition methods were cumbersome and a lack of user-friendly analysis software initially precluded widespread use. Through the advent of matrix transducers enabling real-time three-dimensional echocardiography (3DE) and improvements in analysis software featuring semi-automated volumetric analysis, 3D echocardiography evolved into a simple and fast imaging modality for everyday clinical use. 3DE provides the possibility to evaluate the entire LV in three spatial dimensions during the complete cardiac cycle, offering a more accurate and complete quantitative evaluation the LV. Improved efficiency in acquisition and analysis may provide clinicians with important diagnostic information within minutes. The current article reviews the methodology and application of 3DE for quantitative evaluation of the LV, provides the scientific evidence for its current clinical use, and discusses its current limitations and potential future directions.

Assessment of left ventricular volumes and function by real time three-dimensional echocardiography in a pediatric population: a TomTec versus QLAB comparison

BACKGROUND

Three-dimensional echocardiography (3DE) allows accurate calculation of ventricular volumes despite a remaining geometric assumption on the ventricular shape. Few studies involving full volume reconstruction software have been performed on children. Our aim was to compare the left ventricular (LV) volume measurements obtained with the most used 3D analysis software in a pediatric population.

METHODS

Fifty patients (median age: 9.5 years) without cardiac disease were included in the study. 3DE was performed with the X4-2 or X7-2 matrix probe (ie33, Philips). The LV volume analysis was performed with QLAB 6.0 (semiautomated border detection) and TomTec 4D LV (primary manual tracking with semiautomated border detection).

RESULTS

TomTec analysis feasibility amounted to 94% whereas QLAB analysis feasibility only reached 80% (P = 0.037). The analysis time was shorter with QLAB than TomTec (5 ± 2 versus 6 ± 3 minutes, P < 0.05). The stroke volume, end diastolic and end systolic LV volume measurements performed on the 40 patients were strongly correlated (r > 0.97; P < 0.0001) with minimal bias. The LV ejection fraction was well correlated (r = 0.79; P < 0.0001).

CONCLUSION

3D LV volume quantification is feasible either by using manual or automated reconstruction software in a normal pediatric population. LV Measurements are well correlated. Differences in volume reconstruction algorithms provide specific software performance characteristics. TomTec is a more feasible method but requires a longer analysis time. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Three-dimensional echocardiography using single-heartbeat modality decreases variability in measuring left ventricular volumes and function in comparison to four-beat technique in atrial fibrillation

Background

Three dimensional echocardiography (3DE) approaches the accuracy of cardiac magnetic resonance in measuring left ventricular (LV) volumes and ejection fraction (EF). The multibeat modality in comparison to single-beat (SB) requires breath-hold technique and regular heart rhythm which could limit the use of this technique in patients with atrial fibrillation (AF) due to stitching artifact. The study aimed to investigate whether SB full volume 3DE acquisition reduces inter- and intraobserver variability in assessment of LV volumes and EF in comparison to four-beat (4B) ECG-gated full volume 3DE recording in patients with AF.

Methods

A total of 78 patients were included in this study. Fifty-five with sinus rhythm (group A) and 23 having AF (group B). 4B and SB 3DE was performed in all patients. LV volumes and EF was determined by these two modalities and inter- and intraobserver variability was analyzed.

Results

SB modality showed significantly lower inter- and intraobserver variability in group B in comparison to 4B when measuring LV volumes and EF, except for end-systolic volume (ESV) in intraobserver analysis. There were significant differences when calculating the LV volumes (p < 0.001) and EF (p < 0.05) with SB in comparison to 4B in group B.

Conclusion

Single-beat three-dimensional full volume acquisition seems to be superior to four-beat ECG-gated acquisition in measuring left ventricular volumes and ejection fraction in patients having atrial fibrillation. The variability is significantly lower both for ejection fraction and left ventricular volumes.

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 image modeling tool for quantitative analysis of global and regional cardiac wall motion

OBJECTIVE

To evaluate the Cardiac Image Modeling (CIM 4.6; University of Auckland, Auckland, New Zealand) tool's ability to assess cardiac function via quantitative calculations of global and regional ejection fraction (EF) from magnetic resonance imaging in comparison with a current method of global analysis with Argus (Siemens Medical Solutions) and regional analysis with visual analysis.

BACKGROUND

Global cardiac function is commonly assessed quantitatively by post processing tools that calculate global EF. Currently, regional cardiac function is assessed by subjective visual analysis of wall motion, which can have significant interobserver variability. CIM is a tool that may reduce variability by generating a semi-automated 3-dimensional heart model to calculate quantitative global and regional EF.

MATERIALS AND METHODS

Thirty-one patients (22 men, 9 women; mean age 55.1 +/- 17.5 years) were selected based on global EFs calculated at the time of the clinical visit with the Argus postprocessing tool (Siemens Medical Solutions). Patients were then placed into 2 predetermined categories of normal: EF >or=50% and abnormal: EF <50%. Regional EF was calculated for each segment of a 16-segment cardiac model. Three blinded reviewers used the standard of care assessment of regional function, which was a qualitative grading of the 16 segments into categories of normal or abnormal regional wall motion by visual analysis. CIM quantitatively analyzed global EF and regional EF for each segment. These segments were then sorted into the predetermined categories of normal (EF >or=50%) and abnormal (EF <50%). Level of agreement was conducted via Pearson correlation coefficient and Bland-Altman analysis for global EF analysis and observed proportion of agreement (p(a)), sensitivity, and specificity for regional EF analysis.

RESULTS

Global EF analysis showed a high correlation (r2 = 0.85; y = 0.94x + 4.85, P < 0.001) between the Argus and CIM analyses. Sixteen-segment regional EF analysis showed p(a) averages >0.60. Regional wall motion by short axis slices showed pa averages >0.75, and combined analyses of all 3 reviewers' 16-segment regional data showed an overall total p(a) = 0.79 (sensitivity = 72%, specificity = 88%). Interobserver and intraobserver variability were low (p(a) > 0.65) in this study.

CONCLUSIONS

Global EF analysis of cardiac magnetic resonance imaging by CIM showed high agreement with the commonly used Argus postprocessing tool. Furthermore, CIM is capable of evaluating regional EF with good agreement in comparison with the current visual method. In addition to determining abnormal versus normal cardiac wall motion, CIM is able to add to the analysis a quantitative regional EF for each given segment. As a semi-automated tool, CIM has the potential to reduce reviewer variability and decrease the time required for analysis. In the future, CIM can potentially quantitatively track global and regional changes in patients with heart disease and aid the clinical management throughout the course of the disease.

Assessment of global and regional left ventricular function after surgical revascularization in patients with coronary artery disease by real-time triplane echocardiography

OBJECTIVE

The purpose of this study was to evaluate the capability of real-time triplane echocardiography (RT3PE) for monitoring global and regional systolic function of the left ventricle (LV) after surgical revascularization and for evaluating the effect of surgery and predicting restenosis.

METHODS

Forty-nine patients underwent RT3PE before and at 10 days and 1, 3, and 6 months after coronary artery bypass grafting (CABG). The global systolic function of the LV was assessed with the parameters of end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and stroke volume (SV). The regional myocardial deformation was detected by triplane strain rate imaging. Recovery of myocardial function after surgery and the correlation between global and regional function were investigated.

RESULTS

In 41 of the 49 patients, the EDV and ESV decreased, and the EF and SV increased gradually and showed statistical significance at 3 and 6 months after surgery (P < .05; P < .01). The systolic strain rate (SR(sys)) and systolic strain (S(sys)) increased, and the postsystolic strain index (PSI) decreased progressively after CABG, with significant changes in almost all studied segments at 6 months (P < .05; P < .01). In addition, recovery of the SR(sys), S(sys), and PSI at each follow-up stage after surgery correlated well with EF improvement, with a positive correlation between the SR(sys), S(sys), and EF and a negative correlation between the PSI and EF. Restenosis was suspected in the other 8 patients. The sensitivity, specificity, and accuracy of RT3PE to predict restenosis were 75.00%, 89.47%, and 85.19%, respectively.

CONCLUSIONS

Real-time triplane echocardiography can be used to quantitatively assess global and regional myocardial function. It may represent a new, powerful method to monitor improvement of myocardial function after CABG and to predict restenosis.

Visualization of coronary venous anatomy by cardiovascular magnetic resonance

BACKGROUND

Coronary venous imaging with whole-heart cardiovascular magnetic resonance (CMR) angiography has recently been described using developmental pulse sequences and intravascular contrast agents. However, the practical utility of coronary venous imaging will be for patients with heart failure in whom cardiac resynchronisation therapy (CRT) is being considered. As such complementary information on ventricular function and myocardial viability will be required. The aim of this study was to determine if the coronary venous anatomy could be depicted as part of a comprehensive CMR protocol and using a standard extracellular contrast agent.

METHODS AND RESULTS

Thirty-one 3D whole heart CMR studies, performed after intravenous administration of 0.05 mmol/kg gadolinium DTPA, were reviewed. The cardiac venous system was visualized in all patients. The lateral vein of the left ventricle was present in 74%, the anterior interventricular vein in 65%, and the posterior interventricular vein in 74% of patients. The mean maximum distance of demonstrable cardiac vein on the 3D images was 81.5 mm and was dependent on the quality of the 3D data set. Five patients showed evidence of myocardial infarction on late gadolinium enhancement (LGE) images.

CONCLUSION

Coronary venous anatomy can be reliably demonstrated using a comprehensive CMR protocol and a standard extracellular contrast agent. The combination of coronary venous imaging, assessment of ventricular function and LGE may be useful in the management of patients with LV dysfunction being considered for CRT.

Real-time 3-dimensional echocardiography early after acute myocardial infarction: incremental value of echo-contrast for assessment of left ventricular function

BACKGROUND

Accurate and reproducible assessment of left ventricular (LV) systolic function is important in patients with acute myocardial infarction (AMI). Real-time 3-dimensional echocardiography (RT3DE) is an accurate technique, but it relies heavily on good image quality. The aim of the present study was to evaluate the incremental value of contrast-enhanced RT3DE.

METHODS

A total of 140 consecutive patients (58 +/- 11 years, 78% men) with ST-elevation AMI clinically underwent nonenhanced and contrast-enhanced RT3DE within 24 hours from AMI to evaluate global and regional LV systolic function. Endocardial border definition was graded for each of the 16 LV segments as follows: 0 = border invisible, 1 = border visualized only partially, and 2 = complete visualization of the border. Three image-quality groups (good, fair, and uninterpretable) were identified. Left ventricular volumes and ejection fraction were measured off-line. Wall motion was graded for each visible segment as follows: 1 = normal, 2 = hypokinetic, 3 = akinetic, and 4 = dyskinetic.

RESULTS

During contrast-enhanced RT3DE, as compared with nonenhanced RT3DE, the number of segments with complete visualization of the endocardial border increased from 66% to 84% (P < .001); and the number of patients with a good-quality echocardiogram increased from 59% to 94% (P < .001). Intra- and interobserver agreement for assessment of global and regional LV systolic function improved during contrast-enhanced RT3DE, as compared with nonenhanced RT3DE.

CONCLUSIONS

Assessment of LV systolic function in AMI patients with RT3DE is frequently hampered by suboptimal echocardiographic quality. Contrast-enhanced RT3DE is of incremental value, improving the endocardial border visualization and the reproducibility of LV function assessment.

Semi-automated quantification of left ventricular volumes and ejection fraction by real-time three-dimensional echocardiography

BACKGROUND

Recent studies have shown that real-time three-dimensional (3D) echocardiography (RT3DE) gives more accurate and reproducible left ventricular (LV) volume and ejection fraction (EF) measurements than traditional two-dimensional methods. A new semi-automated tool (4DLVQ) for volume measurements in RT3DE has been developed. We sought to evaluate the accuracy and repeatability of this method compared to a 3D echo standard.

METHODS

LV end-diastolic volumes (EDV), end-systolic volumes (ESV), and EF measured using 4DLVQ were compared with a commercially available semi-automated analysis tool (TomTec 4D LV-Analysis ver. 2.2) in 35 patients. Repeated measurements were performed to investigate inter- and intra-observer variability.

RESULTS

Average analysis time of the new tool was 141s, significantly shorter than 261s using TomTec (p < 0.001). Bland Altman analysis revealed high agreement of measured EDV, ESV, and EF compared to TomTec (p = NS), with bias and 95% limits of agreement of 2.1 +/- 21 ml, -0.88 +/- 17 ml, and 1.6 +/- 11% for EDV, ESV, and EF respectively. Intra-observer variability of 4DLVQ vs. TomTec was 7.5 +/- 6.2 ml vs. 7.7 +/- 7.3 ml for EDV, 5.5 +/- 5.6 ml vs. 5.0 +/- 5.9 ml for ESV, and 3.0 +/- 2.7% vs. 2.1 +/- 2.0% for EF (p = NS). The inter-observer variability of 4DLVQ vs. TomTec was 9.0 +/- 5.9 ml vs. 17 +/- 6.3 ml for EDV (p < 0.05), 5.0 +/- 3.6 ml vs. 12 +/- 7.7 ml for ESV (p < 0.05), and 2.7 +/- 2.8% vs. 3.0 +/- 2.1% for EF (p = NS).

CONCLUSION

In conclusion, the new analysis tool gives rapid and reproducible measurements of LV volumes and EF, with good agreement compared to another RT3DE volume quantification tool.

Single photon emission computed tomography: an alternative imaging modality in left ventricular evaluation

Various diagnostic imaging modalities have been used for quantitative left ventricular (LV) parameters. Because of the suboptimal value of the most widely used technology, two-dimensional (2D) echocardiography, 3D ultrasonographic imaging has improved accuracy for LV volume and function. Single photon emission computed tomography (SPECT) is another diagnostic method where LV volumetric and functional parameters can be accurately provided by gated myocardial perfusion tomographic slices. First pass radionuclide venticulography is another imaging modality which has some practical limitations. Despite lower ejection fraction (EF) values compared with invasive approach, noninvasive techniques are accurate in determination of normal and depressed EF. Noninvasive techniques with 3D approach including gated SPECT are beneficial for not only global but also regional LV evaluation. It has been mentioned that the slight difference between echocardiography and SPECT could be caused by the diverse population studied. The results of diagnostic stress tests support that SPECT is feasible to use in evaluation of LV volume and functional analysis. Magnetic resonance imaging is an expensive modality to use routinely, but it preserves its importance in selected patients for providing precise LV geometric data.

Relative importance of errors in left ventricular quantitation by two-dimensional echocardiography: insights from three-dimensional echocardiography and cardiac magnetic resonance imaging

BACKGROUND

The accuracy of left ventricular (LV) volumes and ejection fraction (EF) on two-dimensional echocardiography (2DE) is limited by image position (IP), geometric assumption (GA), and boundary tracing (BT) errors.

METHODS

Real-time three-dimensional echocardiography (RT3DE) and cardiac magnetic resonance imaging (CMR) were used to determine the relative contribution of each error source in normal controls (n = 35) and patients with myocardial infarctions (MIs) (n = 34). LV volumes and EFs were calculated using (1) apical biplane disk summation on 2DE (IP + GA + BT errors), (2) biplane disk summation on RT3DE (GA + BT errors), (3) 4-multiplane to 8-multiplane surface approximation on RT3DE (GA + BT errors), (4) voxel-based surface approximation on RT3DE (BT error alone) and (5) CMR. By comparing each method with CMR, the absolute and relative contributions of each error source were determined.

RESULTS

IP error predominated in LV volume quantification on 2DE in normal controls, whereas GA error predominated in patients with MIs. Underestimation of volumes on 2DE was overcome by increasing the number of imaging planes on RT3DE. Although 4 equidistant image planes were acceptable, the best results were achieved with voxel-based RT3DE. For EF estimation, IP error predominated in normal controls, whereas BT error predominated in patients with MIs. Nevertheless, one third of the EF estimation error in patients with MIs was due to a combination of IP and GA errors, both of which may be addressed using RT3DE.

CONCLUSIONS

The relative contribution of each source of LV quantitation error on 2DE was defined and quantified. Each source of error differed depending on patient characteristics and LV geometry.

New Echocardiographic Techniques for Evaluating Left Ventricular Myocardial Function

Ultrasound imaging of the heart continues to play an important role in diagnosis and management of patients with cardiovascular diseases. Recent advances in ultrasound technology and introduction of newer imaging modalities have enabled improved assessment of left ventricular myocardial function. Tissue Doppler imaging and 2-dimensional speckle tracking allow more objective quantification of myocardial function in the form of tissue velocities, displacement, strain, and strain rate. Similarly, contrast-enhanced echocardiography and 3-dimensional echocardiography have provided a unique insight into left ventricular form and function that was not possible by unenhanced 2-dimensional echocardiography. In this review, the authors discuss the clinical application of these new imaging techniques in the assessment of left ventricular myocardial function.

Real-time 3-dimensional echocardiography in the operating room

Real-time 3-dimensional transesophageal echocardiography (RT-3D-TEE) represents a novel clinical and intuitively educational perioperative cardiovascular imaging modality. The development of RT-3D-TEE allows for live 3D imaging as it circumvents most of the disadvantages of reconstructive 3D methods. RT-3D-TEE will likely revolutionize perioperative assessment of complex 3D structures, such as the mitral valve (MV), as it provides important mechanistic insights into functional and ischemic mitral regurgitation. The MV is particularly suited to live RT-3D-TEE assessment because of the complex interrelationships among the valve, chordae, papillary muscles, and myocardial walls. The 3D en face view of the MV is in accordance with the surgical view and allows to illustrate the unique saddle shape of the MV annulus and to define and localize mitral leaflet lesions in MV prolapse, endocarditis, or congenital MV abnormalities, all potentially important in guiding surgical repair. RT-3D-TEE will soon be integrated into routine perioperative practice. Its unique ability of real-time acquisition, online rendering and cropping capabilities, accurate identification of the precise pathology and location of cardiac disease, together with its ability to promptly quantify 3D data sets using built-in software, will likely help in transitioning this modality into standard of care.

Assessment of left ventricular volumes using simplified 3-D echocardiography and computed tomography - a phantom and clinical study

Objectives

To compare the accuracy of simplified 3-dimensional (3-D) echocardiography vs. multi-slice computed tomography (MSCT) software for the quantification of left ventricular (LV) volumes.

Design

Three-D echocardiography (3-planes approach) and MSCT-CardIQ software were calibrated by measuring known volumes of 10 phantoms designed to closely mimic blood-endocardium interface. Subsequently, LV volumes were measured with both the methods in 9 patients referred routinely for coronary angiography and the agreement between the measurements was evaluated.

Results

Simplified 3D-echocardiography provided higher degree of agreement between the measured and true phantom volumes (mean difference 0 ± 1 ml, variation range +4 to -4 ml) than MSCT software (mean difference 6 ± 5 ml; variation range +22 to -10 ml). The agreement between LV measurements in the patients was considerably poorer, with significantly larger volumes produced by MSCT (mean difference -23 ± 40 ml, variation between +93 and -138 ml).

Conclusion

Simplified 3-D echocardiography provides more accurate assessment of phantom volumes than MSCT-CardIQ software. The discrepancy between the results of LV measurements with the two methods is even greater and does not warrant their interchangeable diagnostic use.

Three-dimensional echocardiographic assessment of left ventricular function in takotsubo cardiomyopathy

We evaluated left ventricular (LV) function by three-dimensional echocardiography (3DE) in a patient with takotsubo cardiomyopathy (TC). An 82-year-old man was admitted to our hospital with a suspicion of acute myocardial infarction but was diagnosed as TC by coronary angiography and left ventriculography (LVG). Three-dimensional echocardiography showed circular asynergy from the midventricle to the apex associated with hyperkinesis of the base and volumetric data very close to those obtained by LVG. Thus, 3DE is a useful tool in evaluating regional wall motion abnormalities and LV volume in patients with TC.

How accurately, reproducibly, and efficiently can we measure left ventricular indices using M-mode, 2-dimensional, and 3-dimensional echocardiography in children?

BACKGROUND

Measurements of left ventricular (LV) size, mass, and function are the most common and important tasks for echocardiography in clinical practice and research in children with congenital and acquired heart diseases. There are little data to compare the utility of M-mode (MM), 2-dimensional (2D), and 3-dimensional (3D) echocardiographic techniques for quantification of LV indices. The objective of the study was to assess the accuracy, reproducibility, and efficiency of these echocardiographic methods for measurement of LV indices in children.

METHODS

A prospective study was conducted in 20 consecutive children (mean 10.6 +/- 2.8 years, 11 male and 9 female subjects) using conventional MM, 2D, and real-time 3D echocardiography (RT3DE). A Sonos 7500 system (Philips Medical Systems, Andover, MA) was used. M-mode and 2DE measurements were made according to the American Society of echocardiography recommendations. To include the entire LV for volumetric measurement, full-volume 3D data sets were acquired from 4 electrocardiogram gated subvolumes. The 3DE measurements were made off-line manually using 4-plane and 8-plane algorithms by 4D Echo-View (TomTec Imaging Systems, Munich, Germany) and a semiautomated algorithm by QLAB (Philips Medical Systems). Magnetic resonance imaging studies were also performed to determine the LV indices by a disk summation method based on the Simpson principle.

RESULTS

The correlation and agreement between MM, 2D, and RT3D echocardiography and magnetic resonance imaging measurements are good (r = 0.81-0.97) for the 3 methods. The correlation was superior for RT3DE compared with 2DE and MM. The correlation and agreement were similar for the three 3DE methods. The intra- and interobserver variabilities ranged from MM (4.3%-4.8% and 7.0%-8.7%), 2DE (3.3%-4.5% and 5.5%-7.3%), and 3DE (0.4%-2.3%, and 0.2%-4.8%). The total time (acquisition and analysis) used for MM measurements was the least compared with 2DE and 3DE. The total time for 3DE using the semiautomated algorithms was not significantly different compared with that for 2DE.

CONCLUSIONS

Our study showed that MM provides the most efficient assessment of LV indices but is the least accurate and reproducible technique compared with 2DE and 3DE. Three-dimensional echocardiography using both automated and manual analysis algorithm is superior to MM and 2DE for measurements of LV indices, and the automated 3DE algorithm is as efficient as 2DE. Therefore, 3DE using the automated algorithm is the method of choice for quantification of LV indices.

Flow-volume loops derived from three-dimensional echocardiography: a novel approach to the assessment of left ventricular hemodynamics

Background

This study explores the feasibility of non-invasive evaluation of left ventricular (LV) flow-volume dynamics using 3-dimensional (3D) echocardiography, and the capacity of such an approach to identify altered LV hemodynamic states caused by valvular abnormalities.

Methods

Thirty-one patients with moderate-severe aortic (AS) and mitral (MS) stenoses (21 and 10 patients, respectively) and 10 healthy volunteers underwent 3D echocardiography with full volume acquisition using Philips Sonos 7500 equipment. The digital 3D data were post- processed using TomTec software. LV flow-volume loops were subsequently constructed for each subject by plotting instantaneous LV volume data sampled throughout the cardiac cycle vs. their first derivative representing LV flow. After correction for body surface area, an average flow-volume loop was calculated for each subject group.

Results

Flow-volume loops were obtainable in all subjects, except 3 patients with AS. The flow-volume diagrams displayed clear differences in the form and position of the loops between normal individuals and the respective patient groups. In patients with AS, an "obstructive" pattern was observed, with lower flow values during early systole and larger end-systolic volume. On the other hand, patients with MS displayed a "restrictive" flow-volume pattern, with reduced diastolic filling and smaller end-diastolic volume.

Conclusion

Non-invasive evaluation of LV flow-volume dynamics using 3D-echocardiographic data is technically possible and the approach has a capacity to identify certain specific types of alteration of LV flow-volume pattern caused by valvular abnormalities, thus reflecting underlying hemodynamic states specific for these abnormalities.