Effect of Through-Plane and Twisting Motion on Left Ventricular Strain Calculation: Direct Comparison between Two-Dimensional and Three-Dimensional Speckle-Tracking Echocardiography

Inter-fractional portability of deep learning models for lung target tracking on cine imaging acquired in MRI-guided radiotherapy

MRI-guided radiotherapy systems enable beam gating by tracking the target on planar, two-dimensional cine images acquired during treatment. This study aims to evaluate how deep-learning (DL) models for target tracking that are trained on data from one fraction can be translated to subsequent fractions. Cine images were acquired for six patients treated on an MRI-guided radiotherapy platform (MRIdian, Viewray Inc.) with an onboard 0.35 T MRI scanner. Three DL models (U-net, attention U-net and nested U-net) for target tracking were trained using two training strategies: (1) uniform training using data obtained only from the first fraction with testing performed on data from subsequent fractions and (2) adaptive training in which training was updated each fraction by adding 20 samples from the current fraction with testing performed on the remaining images from that fraction. Tracking performance was compared between algorithms, models and training strategies by evaluating the Dice similarity coefficient (DSC) and 95% Hausdorff Distance (HD95) between automatically generated and manually specified contours. The mean DSC for all six patients in comparing manual contours and contours generated by the onboard algorithm (OBT) were 0.68 ± 0.16. Compared to OBT, the DSC values improved 17.0 - 19.3% for the three DL models with uniform training, and 24.7 - 25.7% for the models based on adaptive training. The HD95 values improved 50.6 - 54.5% for the models based on adaptive training. DL-based techniques achieved better tracking performance than the onboard, registration-based tracking approach. DL-based tracking performance improved when implementing an adaptive strategy that augments training data fraction-by-fraction.

Reliable measurement methods for the isovolumic relaxation time: comparisons of dual gate Doppler and seven other methods

PURPOSE

Isovolumic relaxation time (IVRT) is a useful indicator of diastolic dysfunction. However, a measurement method for IVRT has not been established. The Dual Gate Doppler method, which can record two separate pulse-wave Doppler signals simultaneously using two sample gates, may be ideal for measuring IVRT. This study aimed to evaluate the accuracy of IVRT measured using conventional methods versus that measured using the Dual Gate Doppler method.

METHODS

A total of 104 patients (mean age 58 ± 21 years, 48 women) were examined using ultrasound equipment with Dual Gate Doppler at our hospital. In addition to Dual Gate Doppler method, IVRTs were measured using seven different methods: pulsed Doppler (PW method), continuous wave Doppler (CW method), and other methods. The IVRT values obtained using the Dual Gate Doppler method were compared with those measured using other methods.

RESULTS

All IVRTs measured using conventional methods showed a strong correlation with the that measured using the Dual Gate Doppler method. However, there were slight deifferences among the IVRTs depending on the method. The PW method and the PW time difference method using only the PW showed small statistical bias and were not complicated. The IVRT measured using the CW method was significantly longer than that measured using the Dual Gate Doppler method.

CONCLUSIONS

Among the conventional methods, the PW method was the simplest and most practical method for measuring the IVRT in any conditions as arrhythmias. It is important to recognize the characteristics of IVRTs based on the measurement method.

Myocardial strain of the left ventricle by speckle tracking echocardiography: From physics to clinical practice

Speckle tracking echocardiography (STE) is a reliable imaging technique of recognized clinical value in several settings. This method uses the motion of ultrasound backscatter speckles within echocardiographic images to derive myocardial velocities and deformation parameters, providing crucial insights on several cardiac pathological and physiological processes. Its feasibility, reproducibility, and accuracy have been widely demonstrated, being myocardial strain of the various chambers inserted in diagnostic algorithms and guidelines for various pathologies. The most important parameters are Global longitudinal strain (GLS), Left atrium (LA) reservoir strain, and Global Work Index (GWI): based on large studies the average of the lower limit of normality are -16%, 23%, and 1442 mmHg%, respectively. For GWI, it should be pointed out that myocardial work relies primarily on non-invasive measurements of blood pressure and segmental strain, both of which exhibit high variability, and thus, this variability constitutes a significant limitation of this parameter. In this review, we describe the principal aspects of the theory behind the use of myocardial strain, from cardiac mechanics to image acquisition techniques, outlining its limitation, and its principal clinical applications: in particular, GLS have a role in determine subclinical myocardial dysfunction (in cardiomyopathies, cardiotoxicity, target organ damage in ambulatory patients with arterial hypertension) and LA strain in determine the risk of AF, specifically in ambulatory patients with arterial hypertension.

Impact of aortic valve stenosis on myocardial deformation in different left ventricular levels: A three-dimensional speckle tracking echocardiography study

BACKGROUND

Global systolic left ventricular (LV) myocardial function progressively declines as degenerative aortic valve stenosis (AS) progresses. Whether this results in uniformly distributed deformation changes from base to apex has not been investigated.

METHODS

Eighty-five AS patients underwent three-dimensional (3D) echocardiography in this cross-sectional study. Patients were grouped by peak jet velocity into mild (n = 32), moderate (n = 31), and severe (n = 22) AS. 3D speckle tracking derived strain, rotation, twist, and torsion were obtained to assess global LV function and myocardial function at the apical, mid, and basal levels.

RESULTS

Global longitudinal strain (GLS) was lower in patients with severe AS (-16.1 ± 2.4% in mild, -15.5 ± 2.5% in moderate, and -13.5 ± 3.0% in severe AS [all p < .01]). Peak basal and mid longitudinal strain (LS), basal rotation and twist from apical to basal level followed the same pattern, while peak apical LS was higher in moderate AS compared to severe AS (all p < .05). In multivariate analyses, lower GLS was particularly associated with male sex, higher body mass index and peak aortic jet velocity, lower basal LS with higher filling pressure (E/e') and LV mass, lower mid LS with higher RWT and presence of AS symptoms, and lower apical LS with male sex and higher systolic blood pressure, respectively (all p < .05).

CONCLUSION

Using 3D speckle tracking echocardiography reveals regional and global changes in LV mechanics in AS related to the severity of AS, LV remodeling and presence of cardiovascular risk factors.

Transverse and longitudinal right ventricular fractional parameters derived from four-chamber cine MRI are associated with right ventricular dysfunction etiology

Studies of the usefulness of transverse right ventricular (RV) shortening are limited. We retrospectively analyzed the CMR images of 67 patients (age: 50.8 ± 19.0 years; men: 53.7%; Control: n = 20, Overloaded RV (atrial septal defect): n = 15, Constricted RV (pericarditis): n = 17, Degenerated RV (arrhythmogenic right ventricular cardiomyopathy): n = 15) (all enrolled consecutively for each disease) in a single center. We defined RV longitudinal (fractional longitudinal change: FLC) and transverse (fractional transverse change: FTC) contraction parameters. We assessed the FTC/FLC (T/L) ratio on four-chamber cine CMR views and compared the four groups regarding the fractional parameters. FTC had a stronger correlation (R² = 0.650; p < 0.001) with RV ejection fraction than that with FLC (R² = 0.211; p < 0.001) in the linear regression analysis. Both FLC and FTC were significantly lower in the Degenerated RV and Constricted RV groups compared with those in the Control and Overloaded RV groups. The T/L ratio was significantly lower in the Degenerated RV group (p = 0.008), while the Overloaded RV (p = 0.986) and Constricted RV (p = 0.582) groups had preserved T/L ratios, compared with the Control group. Transverse shortening contributes to RV function more significantly compared with longitudinal contraction. Impaired T/L ratios may reflect RV myocardial degeneration. RV fractional parameters may help precisely understand RV dysfunction.

Prediction of Deterioration of Left Ventricular Function Using 3-Dimensional Speckle-Tracking Echocardiography in Patients With Left Bundle-Branch Block

Background Previous studies have demonstrated that 2-dimensional (2D) global longitudinal strain (GLS) is associated with cardiovascular outcomes in patients with left bundle-branch block. However, the predictive value of 3-dimensional (3D) speckle-tracking echocardiography has not yet been investigated in these patients. Methods and Results The authors retrospectively identified 290 patients with left bundle-branch block who underwent echocardiography more than twice. Using speckle-tracking echocardiography, 2D-GLS, 3D-GLS, 3D-global circumferential strain, 3D global radial strain, and 3D global area strain were acquired. The association between 2D and 3D strains and the follow-up left ventricular (LV) ejection fraction (LVEF) was analyzed. The study population was divided into 2 sets: a group with preserved LVEF (baseline LVEF ≥40%) and a group with reduced LVEF (baseline LVEF <40%). After a median follow-up of 29.1 months (interquartile range, 13.1-53.0 months), 14.9% of patients progressed to LV dysfunction in the group with preserved LVEF, and 51.0% of patients showed improved LV function in the group with reduced LVEF. Multivariable analysis of 2D and 3D strains revealed that higher 2D-GLS (odds ratio [OR], 0.65 [95% CI, 0.54-0.78], P<0.001) was highly associated with maintaining LVEF in patients with preserved LVEF. However, a lower 3D-global circumferential strain (OR, 0.61 [95% CI, 0.47-0.78], P<0.001) showed a strong association with persistently reduced LVEF in patients with reduced LVEF. Conclusions Although 2D-GLS showed a powerful predictive value for the deterioration of LV function in the preserved LVEF group, 3D strain, especially 3D-global circumferential strain, can be helpful to predict consistent LV dysfunction in patients with left bundle-branch block who have reduced LVEF.

Right ventricular strain and volume analyses through deep learning-based fully automatic segmentation based on radial long-axis reconstruction of short-axis cine magnetic resonance images

OBJECTIVE

We propose a deep learning-based fully automatic right ventricle (RV) segmentation technique that targets radially reconstructed long-axis (RLA) images of the center of the RV region in routine short axis (SA) cardiovascular magnetic resonance (CMR) images. Accordingly, the purpose of this study is to compare the accuracy of deep learning-based fully automatic segmentation of RLA images with the accuracy of conventional deep learning-based segmentation in SA orientation in terms of the measurements of RV strain parameters.

MATERIALS AND METHODS

We compared the accuracies of the above-mentioned methods in RV segmentations and in measuring RV strain parameters by Dice similarity coefficients (DSCs) and correlation coefficients.

RESULTS

DSC of RV segmentation of the RLA method exhibited a higher value than those of the conventional SA methods (0.84 vs. 0.61). Correlation coefficient with respect to manual RV strain measurements in the fully automatic RLA were superior to those in SA measurements (0.5-0.7 vs. 0.1-0.2).

DISCUSSION

Our proposed RLA realizes accurate fully automatic extraction of the entire RV region from an available CMR cine image without any additional imaging. Our findings overcome the complexity of image analysis in CMR without the limitations of the RV visualization in echocardiography.

13N-ammonia positron emission tomography-derived left-ventricular strain in patients after heart transplantation validated using cardiovascular magnetic resonance feature tracking as reference

OBJECTIVE

Heart transplant rejection leads to cardiac allograft vasculopathy (CAV). ¹³N-ammonia positron emission tomography (PET) can be useful in detecting CAV, as it can evaluate both epicardial vessels and microvasculature. In this study, we evaluated the regional wall motion in heart transplant patients using our PET-specific feature-tracking (FT) algorithm for myocardial strain calculation and validated it using a cardiovascular magnetic resonance (CMR) FT strain as a reference.

METHODS

A total of 15 heart transplant patients who underwent both ¹³N-ammonia PET and CMR within 3 months were retrospectively enrolled. The same slice position of short-axis cine images of the middle slice of left ventricle (LV) and the same slice position of horizontal long-axis cine images were selected for the two modalities to measure the circumferential strain (CS) and longitudinal strain (LS), respectively. Based on the FT technique, time-strain curves were calculated by semi-automatic tracking of the endocardial contour on cine images throughout a cardiac cycle. The peak value in the time-strain curve was defined as the representative value. Correlations of CS and LS between PET and CMR were analyzed using Pearson correlation coefficients. The inter-modality error of strain measurements was evaluated using intraclass correlation coefficients (ICCs) with two-way random single measures.

RESULTS

Excellent correlations of CS and LS between PET and CMR were observed (CS: r = 0.80; p < 0.01; LS: r = 0.87; p < 0.01). Excellent ICCs were observed (0.89 and 0.85) in CS and LS derived from PET.

CONCLUSIONS

We propose the first PET strain showing an excellent agreement with the CMR strain and high reproducibility in measurement.

Role of Echocardiography for the Perioperative Assessment of the Right Ventricle

Purpose of Review

This review aims to highlight the perioperative echocardiographic evaluation of right ventricular (RV) function with strengths and limitations of commonly used and evolving techniques. It explains the value of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) and describes the perioperative changes of RV function echocardiographers should be aware of.

Recent Findings

RV dysfunction is an entity with strong influence on outcome. However, its definition and assessment in the perioperative interval are not well-defined. Moreover, values assessed by TTE and TEE are not interchangeable; while some parameters seem to correlate well, others do not. Myocardial strain analysis and three-dimensional echocardiography may overcome the limitations of conventional echocardiographic measures and provide further insight into perioperative cardiac mechanics.

Summary

Echocardiography has become an essential part of modern anesthesiology in patients with RV dysfunction. It offers the opportunity to evaluate not only global but also regional RV function and distinguish alterations of RV contraction.

Perioperative Course of Three-Dimensional-Derived Right Ventricular Strain in Coronary Artery Bypass Surgery: A Prospective, Observational, Pilot Trial

OBJECTIVES

Few data exist on perioperative three-dimensional-derived right ventricular strain. The authors aimed to describe the perioperative course of three-dimensional-derived right ventricular strain in coronary artery bypass graft (CABG) surgery patients.

DESIGN

Prospective, observational, pilot trial.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 40 patients with preserved left ventricular and right ventricular (RV) function undergoing isolated on-pump CABG surgery.

INTERVENTIONS

Three-dimensional strain analysis and standard echocardiographic evaluation of RV function were performed preoperatively (T1) and postoperatively (T4) with transthoracic echocardiography (TTE) and intraoperatively before sternotomy (T2) and after sternotomy (T3) with transesophageal echocardiography (TEE). All echocardiographic measurements were performed under stable hemodynamic conditions and predefined fluid management without any vasoactive support.

MEASUREMENTS AND MAIN RESULTS

The measurements of three-dimensional-derived RV free-wall strain (3D-RV FWS) and RV ejection fraction were performed using TomTec 4D RV-Function 2.0 software. Philips QLAB 10.8 was used to analyze tissue velocity of the tricuspid annulus, tricuspid annular systolic excursion, and RV fractional area change. There were no significant differences (median [interquartile range {IQR}]) between preoperative TTE and intraoperative TEE measurements for 3D-RV FWS (T1 v T2: -22.35 [IQR -17.70 to -27.22] v -24.35 [IQR -20.63 to -29.88]; not significant). 3D-RV FWS remained unchanged after sternotomy (T2 v T3: -24.35 [IQR -20.63 to -29.88] v -23.75 [IQR -20.25 to -29.28]; not significant) but deteriorated significantly after CABG (T1 v T4: -22.35 [IQR -17.70 to -27.22] v -18.5 [IQR -16.90 to -21.65]; p = 0.004).

CONCLUSION

In patients undergoing on-pump CABG, 3D-RV FWS values for awake, spontaneously breathing patients measured with TTE and values assessed in patients under general anesthesia with TEE did not significantly differ. Three-dimensional RV FWS did not change after sternotomy but deteriorated after on-pump CABG.

Impact of three-dimensional global longitudinal strain for patients with acute myocardial infarction

AIMS

In patients with ST-segment elevation myocardial infarction (STEMI), predicting left ventricular (LV) remodelling (LVR) and prognosis is important. We explored the clinical usefulness of three-dimensional (3D) speckle-tracking echocardiography to predict LVR and prognosis in STEMI.

METHODS AND RESULTS

The study group comprised 255 first STEMI patients (65 years; 210 men) treated with primary percutaneous coronary intervention between April 2008 and May 2012 at Yokohama City University Medical Center. Baseline global longitudinal strain (GLS) was measured with two-dimensional (2D) and 3D speckle-tracking echocardiography. Within 48 of admission, standard 2D echocardiography and 3D full-volume imaging were performed, and 2D-GLS and 3D-GLS were calculated. Infarct size was estimated by 99mTc-sestamibi single-photon emission computed tomography. Echocardiography was performed at 1 year repeatedly in 239 patients. The primary endpoint was LVR, defined as an increase of 20% of LV end-diastolic volume index and major adverse cardiac and cerebrovascular events (MACE: cardiac death, non-fatal MI, heart failure, and ischaemic stroke) at 1 year, and the secondary endpoint was cardiac death and heart failure. Patients were followed for 1 year; 64, 25, and 16 patients experienced LVR, MACE, and the secondary endpoint, respectively. Multivariate analysis revealed that 3D-GLS was the strongest predictor of LVR (odds ratio = 1.437, 95% CI: 1.047-2.257, P = 0.02), MACE (odds ratio = 1.443, 95% CI: 1.240-1.743, P = 0.0002), and the secondary end point (odds ratio = 1.596, 95% CI: 1.17-1.56, P < 0.0001). Receiver-operating characteristic curve analysis showed that 3D-GLS was superior to 2D-GLS in predicting LVR and 1-year prognosis.

CONCLUSION

3D-GLS obtained immediately after STEMI is independently associated with LVR and 1-year prognosis.

A review of current trends in three-dimensional analysis of left ventricular myocardial strain

Three-dimensional (3D) left ventricular (LV) myocardial strain measurements using transthoracic 3D echocardiography speckle tracking analysis have several advantages over two-dimensional (2D) LV strain measurements, because 3D strain values are derived from the entire LV myocardium, yielding more accurate estimates of global and regional LV function. In this review article, we summarize the current status of 3D LV myocardial strain. Specifically, we describe how 3D LV strain analysis is performed. Next, we compare characteristics of 2D and 3D strain, and we explain validation of 3D strain measurements, feasibility and measurement differences between 2D and 3D strain, reference values of 3D strain, and its applications in several clinical scenarios. In some parts of this review, we used a meta-analysis to draw reliable conclusions. We also describe the added value of 3D over 2D strain in several specific pathologies and prognoses. Finally, we discuss novel techniques using 3D strain and suggest its future directions.

Three-Dimensional Echocardiography - Role in Clinical Practice and Future Directions

Echocardiography has become an extension of the physical examination in cardiovascular practice. Frequently, it is used to confirm a clinical diagnostic suspicion. Another important role is to detect the underlying cardiovascular lesion to explain a patient's symptom complex or an abnormality found on chest radiography, electrocardiography, or cardiac enzyme tests. Patients are referred to the echocardiography laboratory because of their symptoms or due to non-specific laboratory abnormalities, and echocardiographers are expected to provide a definite diagnosis or a therapeutic clue. The introduction of the matrix array transducer into clinical practice allowed the acquisition of three-dimensional (3D) datasets. 3D echocardiography (3DE) has many advantages over 2-dimensional echocardiography, such as: (1) improved visualization of the complex shapes and spatial relations between cardiac structures; (2) improved quantification of the cardiac volumes and function; and (3) improved display and assessment of valve dysfunction. 3DE is increasingly utilized during routine clinical practice. This review article is aimed to examine the current clinical utility and future directions of 3DE.

Quantification of left atrial wall motion in healthy horses using two-dimensional speckle tracking

INTRODUCTION

The mechanical function of the left atrium (LA) plays a pivotal role in modulation of left ventricular filling. Assessment of LA function might be a clinically useful prognostic tool for horses with mitral regurgitation or atrial fibrillation. However, the most accurate, reliable, and clinically useful methods to assess LA myocardial function are yet to be determined. The objective of this study was to describe the methods for quantification of LA wall motion using two-dimensional speckle tracking (2DST) echocardiography in healthy Warmblood horses to quantify measurement variability, to calculate reference intervals for 2DST variables, and to investigate their relationship to sex, age, body weight, and heart rate.

ANIMALS, MATERIALS, AND METHODS

Twenty-six healthy Warmblood horses were included. 2DST analyses of LA wall motion were performed on digitally stored cine-loop recordings of a standardized right-parasternal four-chamber view focusing on the LA. Longitudinal strain, longitudinal strain rate, and time to peak LA contraction were measured to characterize LA contractile, reservoir, and conduit function. Intraobserver and interobserver measurement variability was quantified, and reference intervals were calculated.

RESULTS

The coefficient of variation for intraobserver and interobserver measurement variability ranged between 2.0-11.1% and 5.1-15.4%, respectively, for global strain, strain rate, and time to peak LA contraction. Reference intervals for healthy Warmblood horses were reported.

CONCLUSION

This study shows that 2DST is a feasible and reliable method to quantify LA wall motion throughout the cardiac cycle in healthy Warmblood horses. Further studies are required to establish the clinical value of 2DST for assessment of LA function.

A left ventricular phantom for 3D echocardiographic twist measurements

Traditional two-dimensional (2D) ultrasound speckle tracking echocardiography (STE) studies have shown a wide range of twist values, also for normal hearts, which is due to the limitations of short-axis 2D ultrasound. The same limitations do not apply to three-dimensional (3D) ultrasound, and several studies have shown 3D ultrasound to be superior to 2D ultrasound, which is unreliable for measuring twist. The aim of this study was to develop a left ventricular twisting phantom and to evaluate the accuracy of 3D STE twist measurements using different acquisition methods and volume rates (VR). This phantom was not intended to simulate a heart, but to function as a medium for ultrasound deformation measurement. The phantom was made of polyvinyl alcohol (PVA) and casted using 3D printed molds. Twist was obtained by making the phantom consist of two PVA layers with different elastic properties in a spiral pattern. This gave increased apical rotation with increased stroke volume in a mock circulation. To test the accuracy of 3D STE twist, both single-beat, as well as two, four and six multi-beat acquisitions, were recorded and compared against twist from implanted sonomicrometry crystals. A custom-made software was developed to calculate twist from sonomicrometry. The phantom gave sonomicrometer twist values from 2.0° to 13.8° depending on the stroke volume. STE software tracked the phantom wall well at several combinations of temporal and spatial resolution. Agreement between the two twist methods was best for multi-beat acquisitions in the range of 14.4–30.4 volumes per second (VPS), while poorer for single-beat and higher multi-beat VRs. Smallest offset was obtained at six-beat multi-beat at 17.1 VPS and 30.4 VPS. The phantom proved to be a useful tool for simulating cardiac twist and gave different twist at different stroke volumes. Best agreement with the sonomicrometer reference method was obtained at good spatial resolution (high beam density) and a relatively low VR. 3D STE twist values showed better agreement with sonomicrometry for most multi-beat recordings compared with single-beat recordings.

Three-dimensional echocardiography to assess left ventricular geometry and function

Introduction: Quantification of left ventricular (LV) size and function represents the most frequent indication for an echocardiographic study. New echocardiographic techniques have been developed over the last decades in an attempt to provide a more comprehensive, accurate, and reproducible assessment of LV function.Areas covered: Although two-dimensional echocardiography (2DE) is the recommended imaging modality to evaluate the LV, three-dimensional echocardiography (3DE) has proven to be more accurate, by avoiding geometric assumptions about LV geometry, and to have incremental value for outcome prediction in comparison to conventional 2DE. LV shape (sphericity) and mass are actually measured with 3DE. Myocardial deformation analysis using 3DE can early detect subclinical LV dysfunction, before any detectable change in LV ejection fraction.Expert opinion: 3DE eliminates the errors associated with foreshortening and geometric assumptions inherent to 2DE and 3DE measurements approach very closely those obtained by CMR (the current reference modality), while maintaining the unique clinical advantage of a safe, highly cost/effective, portable imaging technique, available to the cardiologist at bedside to translate immediately the echocardiography findings into the clinical decision-making process.

Three-dimensional myocardial strain correlates with murine left ventricular remodelling severity post-infarction

Heart failure continues to be a common and deadly sequela of myocardial infarction (MI). Despite strong evidence suggesting the importance of myocardial mechanics in cardiac remodelling, many MI studies still rely on two-dimensional analyses to estimate global left ventricular (LV) function. Here, we integrated four-dimensional ultrasound with three-dimensional strain mapping to longitudinally characterize LV mechanics within and around infarcts in order to study the post-MI remodelling process. To induce infarcts with varying severities, we separated 15 mice into three equal-sized groups: (i) sham, (ii) 30 min ischaemia-reperfusion, and (iii) permanent ligation of the left coronary artery. Four-dimensional ultrasound from a high-frequency small animal system was used to monitor changes in LV geometry, function and strain over 28 days. We reconstructed three-dimensional myocardial strain maps and showed that strain profiles at the infarct border followed a sigmoidal behaviour. We also identified that mice with mild remodelling had significantly higher strains in the infarcted myocardium than those with severe injury. Finally, we developed a new approach to non-invasively estimate infarct size from strain maps, which correlated well with histological results. Taken together, the presented work provides a thorough approach to quantify regional strain, an important component when assessing post-MI remodelling.

3-Dimensional Echocardiography: Latest Developments and Future Directions

The ongoing refinements in 3-dimensional (3D) echocardiography technology continue to expand the scope of this imaging modality in clinical cardiology by offering new features that stem from the ability to image the heart in its complete dimensionality. Over the years, countless publications have described these benefits and tested new frontiers where 3D echocardiographic imaging seemed to offer promising ways to improve patients' care. These include improved techniques for chamber quantification and novel ways to visualize cardiac valves, including 3D printing, virtual reality, and holography. The aims of this review article are to focus on the most important developments in the field in the recent years, discuss the current utility of 3D echocardiography, and highlight several interesting future directions.

Comparison of left ventricular systolic function by 2D speckle-tracking echocardiography between normal pregnant women and pregnant women with preeclampsia

Introduction: In light of previous studies reporting the significant effects of preeclampsia on cardiac dimensions, we sought to evaluate changes in the left ventricular (LV) systolic and diastolic functions in patients with preeclampsia with a view to investigating changes in cardiac strain.

Methods: This cross-sectional study evaluated healthy pregnant women and pregnant women suffering from preeclampsia who were referred to our hospital for routine healthcare services. LV strain was measured by 2D speckle-tracking echocardiography.

Results: Compared with the healthy group, echocardiography in the group with preeclampsia showed a significant increase in the LV end-diastolic diameter (47.43 ± 4.94 mm vs 44.84 ± 4.30 mm; P = 0.008), the LV end-systolic diameter (31.16 ± 33.3 mm vs 29.20 ± 3.75 mm; P = 0.008), and the right ventricular diameter (27.93 ± 1.71 mm vs 24.53 ± 23.3; P = 0.001). The mean global longitudinal strain was -18.69 ± 2.8 in the group with preeclampsia and -19.39 ± 3.49 in the healthy group, with the difference not constituting statistical significance (P = 0.164). The mean global circumferential strain in the groups with and without preeclampsia was -20.4 ± 12.4 and -22.68 ± 5.50, respectively, which was significantly lower in the preeclampsia group (P = 0.028).

Conclusion: The development of preeclampsia was associated with an increase in the right and left ventricular diameters, as well as a decrease in the ventricular systolic function, demonstrated by a decline in global circumferential strain.

Regional dynamics of fractal dimension of the left ventricular endocardium from cine computed tomography images

We present a method to leverage the high fidelity of computed tomography (CT) to quantify regional left ventricular function using topography variation of the endocardium as a surrogate measure of strain. 4DCT images of 10 normal and 10 abnormal subjects, acquired with standard clinical protocols, are used. The topography of the endocardium is characterized by its regional values of fractal dimension (F D ), computed using a box-counting algorithm developed in-house. The averageF D in each of the 16 American Heart Association segments is calculated for each subject as a function of time over the cardiac cycle. The normal subjects show a peak systolic percentage change inF D of 5.9 % ± 2 % in all free-wall segments, whereas the abnormal cohort experiences a change of 2 % ± 1.2 % ( p < 0.00001 ). Septal segments, being smooth, do not undergo large changes inF D . Additionally, a principal component analysis is performed on the temporal profiles ofF D to highlight the possibility for unsupervised classification of normal and abnormal function. The method developed is free from manual contouring and does not require any feature tracking or registration algorithms. TheF D values in the free-wall segments correlated well with radial strain and with endocardial regional shortening measurements.

Incorporating three-dimensional echocardiography into clinical practice

Three-dimensional echocardiography (3DE) has many advantages over two-dimensional echocardiography, such as (1) improved visualization of the complex shapes and spatial relations between cardiac structures, (2) improved quantification of the cardiac volumes and function, and (3) improved display and assessment of valve dysfunction. The aim of this review article is to focus on the current clinical utility of 3DE.

Assessment of Myocardial Ischemic Memory Using Three-Dimensional Speckle-Tracking Echocardiography: A Novel Integrated Analysis of Early Systolic Lengthening and Postsystolic Shortening

BACKGROUND

Persistence of subtle abnormal myocardial deformation such as postsystolic shortening (PSS) after transient ischemia can be used to diagnose a history of myocardial ischemia (myocardial ischemic memory). Furthermore, early systolic lengthening (ESL) has recently attracted attention as another marker of myocardial ischemia. However, it is unclear whether the persistence of such abnormal deformation can be detected by three-dimensional (3D) speckle-tracking echocardiography, which has relatively low spatial and temporal resolution compared with two-dimensional echocardiography. The aim of this study was to evaluate the diagnostic accuracy of myocardial ischemic memory and its spatial extent using 3D speckle-tracking echocardiography.

METHODS

The left circumflex coronary artery was occluded for 2 min, followed by reperfusion, in 33 dogs. Their hemodynamic and 3D echocardiographic data were chronologically acquired. Peak systolic strain, early systolic strain index as a parameter of ESL, postsystolic strain index as a parameter of PSS, and myocardial dysfunction index as a combined parameter of ESL and PSS were analyzed in all left ventricular segments.

RESULTS

At the center of the risk area, early systolic strain index and postsystolic strain index significantly increased until 20 min after reperfusion compared with baseline, although peak systolic strain recovered by 20 min. Myocardial dysfunction index significantly increased for >20 min after reperfusion and allowed better diagnostic accuracy of ischemic memory than the other parameters. In the 147 risk segments, abnormal values of myocardial dysfunction index remained in 49 segments (33%) at 20 min after reperfusion, whereas abnormal peak systolic strain was observed in only 13 segments (9%).

CONCLUSIONS

ESL and PSS persisted after transient ischemia and could be detected by 3D speckle-tracking echocardiography. Integrated analysis of ESL and PSS provided higher diagnostic accuracy of ischemic memory. This method may be useful for detecting transient ischemic insults in patients after the disappearance of anginal attack.

Clinical usefulness of right ventricular 3D area strain in the assessment of treatment effects of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: comparison with 2D feature-tracking MRI

OBJECTIVES

To evaluate the usefulness of right ventricular (RV) area strain analysis via cardiac MRI (CMRI) as a tool for assessing the treatment effects of balloon pulmonary angioplasty (BPA) in inoperable chronic thromboembolic pulmonary hypertension (CTEPH), RV area strain was compared to two-dimensional (2D) strain with feature-tracking MRI (FTMRI) before and after BPA.

METHODS

We retrospectively analyzed 21 CTEPH patients who underwent BPA. End-systolic global area strain (GAS), longitudinal strain (LS), circumferential strain (CS), and radial strain (RS) were measured before and after BPA. Changes in GAS and RV ejection fraction (RVEF) values after BPA were defined as ΔGAS and ΔRVEF. Receiver operating characteristic (ROC) analyses were performed to determine the optimal cutoff of the strain at after BPA for detection of improved patients with decreased mean pulmonary artery pressure (mPAP) less than 30 mmHg and increased RVEF more than 50%.

RESULTS

ROC analysis revealed the optimal cutoffs of strains (GAS, LS, CS, and RS) for identifying improved patients with mPAP < 30 mmHg (cutoff (%) = - 41.2, - 13.8, - 16.7, and 14.4: area under the curve, 0.75, 0.56, 0.65, and 0.75) and patients with RVEF > 50% (cutoff (%) = - 37.2, - 29.5, - 2.9, and 14.4: area under the curve, 0.81, 0.60, 0.56, and 0.56).

CONCLUSIONS

Area strain analysis via CMRI may be a more useful tool for assessing the treatment effects of BPA in patients with CTEPH than 2D strains with FTMRI.

KEY POINTS

• Area strain values can detect improvement of right ventricular (RV) pressure and function after balloon pulmonary angioplasty (BPA) equally or more accurately than two-dimensional strains. • Area strain analysis is a useful analytical method that reflects improvements in complex RV myocardial deformation by BPA. • Area strain analysis is a robust method with reproducibility equivalent to that of 2D strain analysis.

Quantitative Assessment of the Effect of the Out-of-Plane Movement of the Homogenous Ellipsoidal Model of the Left Ventricle on the Deformation Measures Estimated Using 2-D Speckle Tracking-An In-Silico Study

Effect of the out-of-plane (OOP) movement amplitude on estimates of global displacements (radial, circumferential) and strains (radial , circumferential ) was studied in an ellipsoidal model of the left ventricle using finite-element modeling (FEM), synthetic ultrasonic data, and short-axis view. This effect was assessed using median of the absolute relative error (RE) of the global parameters. FEM provided node displacements for synthetic ultrasonic data and reference data generation. Displacements were estimated using block-matching (BM) and B-spline (BS) methods. FEM-derived data analysis, free from errors resulting from speckle tracking, indicated that the tissue motion introduced REs of global strain estimates below 4.5%. The effect of the OOP motion amplitude on strain estimates was strain specific and depended on the displacement estimation method. In the case of , the increase of the OOP amplitude resulted in quasi-linear increase of the RE from approximately 10% to 15%. The modulus of the end-systolic (ES) errors of the estimates almost linearly increased with increasing OOP amplitude approximately from 10% to 16%. REs of the estimate were close to 80% and 40%, respectively, in the case of the BM and BS methods, and increased with increasing OOP amplitude. The modulus of the ES errors of the estimates in the case of the BS method was about -40% and showed low sensitivity to the OOP amplitude; in the BM case, these errors varied approximately from -70% to -58% for OOP amplitude from 0 to 15 mm.

Three-Dimensional Echocardiography-derived strain values acquired by a novel analysis program

OBJECTIVE

This in vitro study calculated longitudinal strain (LS) from different ultrasound systems (GE Vivid E9 and Philips IE 33) before and after myocardial infarct (MI) using a vendor-independent analysis software package (TomTec's 4D LV Analysis) to validate the variation of two ultrasound systems.

METHODS

Ten freshly harvested porcine hearts were passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30-70 mL. Full-volume three-dimensional echocardiography (3DE) data were acquired before and after MI using two different ultrasound systems. LS was derived from TomTec and validated against sonomicrometry data.

RESULTS

Linear regression analyses showed excellent correlations between TomTec-calculated LS values and sonomicrometry data for both normal and simulated MI groups (GE: R²  = 0.72/0.68, Philip: R²  = 0.71/0.66). Bland-Altman analyses demonstrated overestimation of echo-derived strain values for all groups. Both ultrasound system-derived strain values demonstrated decreased LS after MI, and the average change in strain after infarct was roughly 30% in GE images and 25% in Philips images.

CONCLUSIONS

Both GE and Philips echocardiographic systems can be analyzed with TomTec's program, and these images correlated well with sonomicrometry with acceptable variations.

Vectors through a cross-sectional image (VCI): A visualization method for four-dimensional motion analysis for cardiac computed tomography

BACKGROUND

Cardiac computed tomography (CT) has the potential for fully four-dimensional (4D for 3D plus time) motion analysis of the heart. We aimed at developing a method for assessment and presentation of the 4D motion for multi-phase, contrast-enhanced cardiac CT data sets and demonstrating its clinical applicability.

METHODS

Four patients with normal cardiac function, old myocardial infarction (OMI), takotsubo cardiomyopathy, and hypertrophic cardiomyopathy (HCM) underwent contrast-enhanced cardiac CT for one heartbeat using a 320-row CT scanner with no tube current modulation. CT images for 10 cardiac phases (with a 10%-increment of the R-R interval) were reconstructed with the isotropic effective resolution of (0.5 mm)³ An image-based motion-estimation (iME) algorithm, developed previously, has been used to estimate a time series of 3D cardiac motion, from the end-systole to the other nine phases. The iME uses down-sampled images with a resolution of (1.0 mm)³ deforms the end-systole images non-rigidly to match images at other phases. Once the agreement is maximized, iME outputs a 3D motion vector defined for each voxel for each phase, that smoothly changes over voxels and phases. The proposed visualization method, which is called "vectors through a cross-sectional image (VCI)," presents 3D vectors from the end-diastole to the end-systole as arrows with an end-diastole CT slice. We performed visual assessment of the VCI with calculated the mean vector lengths to evaluate regional left ventricular (LV) contraction.

RESULTS

The VCI images showed the magnitude and direction of systolic 3D vectors, including the through-plane motion, and successfully visualized the relations of LV wall segments and abnormal regional wall motion. Decreased regional motion and asymmetric motion due to hypokinetic infarct segment, takotsubo cardiomyopathy, and hyper trophic cardiomyopathy was clearly observed. It was easy to appreciate the relation of the abnormal regional wall motion to the affected LV wall segments. The mean vector lengths of the affected segments with pathologies were clearly smaller than the other unaffected segments (1.2-1.7 mm versus 2.5-4.7 mm).

CONCLUSIONS

VCI images could capture the magnitude and direction of through-plane motion and show the relations of LV wall segments and abnormal wall motion.

Age- and Sex-Related Influences on Left Ventricular Mechanics in Elderly Individuals Free of Prevalent Heart Failure: The ARIC Study (Atherosclerosis Risk in Communities)

BACKGROUND

Advanced age is related to left ventricular (LV) remodeling. We sought to investigate the relationships between aging, elevated hemodynamic load, cardiac mechanics, and LV remodeling in an elderly community-based population.

METHODS AND RESULTS

We studied 1105 subjects (76±5 years, 61% women) without prevalent heart failure, who attended the visit 5 of the ARIC study (Atherosclerosis Risk in Communities). LV global longitudinal strain, global circumferential strain, and torsion indices were analyzed using 3-dimensional echocardiography. Advanced age was associated with greater LV concentricity, lower myocardial diastolic relaxation, reduced global longitudinal strain (adjusted estimate, 0.39±0.19% (SE)/decade; P=0.038), borderline greater global circumferential strain (adjusted estimate, -0.59±0.36% (SE)/decade; P=0.08), and higher torsion indices (adjusted estimate for torsion, 0.33±0.04° (SE)/decade; P<0.001). In addition, greater concentricity was associated with decreased global longitudinal strain and greater torsion in multivariable models (all P<0.001). Women showed smaller LV cavity size, greater concentricity, lower myocardial relaxation velocity E', though demonstrated greater global longitudinal strain, global circumferential strain, and torsion than men (all P<0.05). Overall, subjects with hypertension and increasing age were more likely to have higher torsion, though the association between advanced age and greater torsion was more pronounced in women than in men (both interaction P<0.05).

CONCLUSIONS

In an asymptomatic, senescent community-dwelling population, we observed a distinct, sex-specific pattern of cardiac remodeling. Although we observed worse diastolic and longitudinal function with advanced age or elevated load in both sexes, a significant increase of torsion was more pronounced in women.

Three-Dimensional Left Ventricular Torsion in Patients With Dilated Cardiomyopathy - A Marker of Disease Severity

BACKGROUND

LV twist has a key role in maintaining left ventricular (LV) contractility during exercise. The purpose of this study was to investigate LV torsion instead of twist as a surrogate marker of peak oxygen uptake (peak V̇O₂) assessed by cardiopulmonary exercise testing (CPET) in patients with non-ischemic dilated cardiomyopathy (DCM).Methods and Results:We evaluated 45 outpatients with DCM (50±12 years, 24% females) with 3D speckle-tracking electrocardiography prior to CPET. LV torsion, LV ejection fraction (EF), LV diastolic function, LV global longitudinal (GLS) and circumferential (GCS) strain were quantified. A reduced functional capacity (FC) was defined as a peak V̇O₂<20 mL/kg/min. LV torsion correlated most strongly with peak V̇O₂(r=0.76, P<0.001). LV torsion instead of twist was an independent predictor of peak V̇O₂(B: 0.59 to 0.71, P<0.001) in multivariable analyses. Impaired LV torsion <0.61 degrees/cm was able to predict a reduced FC with higher sensitivity and specificity (0.91 and 0.81; area under the curve (AUC): 0.88, P<0.001) than LV EF, GLS or GCS (AUC 0.64, 0.63 and 0.66; P<0.05 for differences in AUC).

CONCLUSIONS

Peak V̇O₂correlated more strongly with LV torsion than with LV diastolic function, LV EF, GLS or GCS. LV torsion had high accuracy in identifying patients with a reduced FC.

Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good acoustic windows and the non-invasive nature of the technique. The aim of this paper is to provide a review of the optimal application of 3DE in CHD including technical considerations, image orientation, application to different lesions, procedural guidance, and functional assessment.

Mitigation of Variability among 3D Echocardiography-Derived Regional Strain Values Acquired by Multiple Ultrasound Systems by Vendor Independent Analysis

Introduction

This study compared the variability of 3D echo derived circumferential and longitudinal strain values computed from vendor-specific and vendor-independent analyses of images acquired using ultrasound systems from different vendors.

Methods

Ten freshly harvested porcine hearts were studied. Each heart was mounted on a custom designed phantom and driven to simulate normal cardiac motion. Cardiac rotation was digitally controlled and held constant at 5°, while pumped stroke volume (SV) ranged from 30-70ml. Full-volume image data was acquired using three different ultrasound systems from different vendors. The image data was analyzed for longitudinal and circumferential strains (LS, CS) using both vendor-specific and vendor-independent analysis packages.

Results

Good linear relationships were observed for each vendor-specific analysis package for both CS and LS at the mid-anterior segment, with correlation coefficients ranging from 0.82–0.91 (CS) and 0.86–0.89 (LS). Comparable linear regressions were observed for results determined by a vendor independent program (CS: R = 0.82–0.89; LS: R = 0.86–0.89). Variability between analysis packages was examined via a series of ANOVA tests. A statistical difference was found between vendor-specific analysis packages (p<0.001), while no such difference was observed between ultrasound systems when using the vendor-independent program (p>0.05).

Conclusions

Circumferential and longitudinal regional strain values differ when quantified by vendor-specific analysis packages; however, this variability is mitigated by use of a vendor-independent quantification method. These results suggest that echocardiograms acquired using different ultrasound systems could be meaningfully compared using vendor-independent software.

Feasibility of Automated Three-Dimensional Rotational Mechanics by Real-Time Volume Transthoracic Echocardiography: Preliminary Accuracy and Reproducibility Data Compared with Cardiovascular Magnetic Resonance

BACKGROUND

Three-dimensional (3D) speckle-tracking echocardiography (STE) for myocardial strain imaging may be superior to two-dimensional STE, especially with respect to rotational mechanics. Automated strain measurements from nonstitched 3D STE may improve work flow and clinical utility. The aim of this study was to test the feasibility of model-based 3D STE for the automated measurement of voxel circumferential strain (Ecc) and myocardial rotation.

METHODS

Thirty-five individuals (12 healthy volunteers, 12 patients with dilated cardiomyopathy, and 11 patients with hypertensive left ventricular [LV] hypertrophy) were prospectively studied. The latter two groups did not have significant coronary artery disease on coronary arteriography. Tagged cardiovascular magnetic resonance (CMR) and feature-tracking CMR were used as reference standards. Regional (apex and mid left ventricle) and slice (within a region) Ecc and rotation were measured by real-time volume transthoracic echocardiography (nonstitched) using an automated algorithm.

RESULTS

Compared with both CMR techniques, apical and mid-LV Ecc (concordance correlation coefficients [CCCs], 0.84-0.95 and 0.48-0.68) and rotation (CCCs, 0.70-0.95 and 0.42-0.68) showed excellent, good, and moderate agreement, respectively. At the LV base, rotation showed poor agreement with CMR methods (CCC, 0.04-0.21), consistent with previous descriptions, but calculated LV twist showed moderate to good correlation with CMR techniques (CCC, 0.61-0.84). However, the 95% CI for measurements between techniques was wide, emphasizing the challenges in comparing voxel deformation by 3D echocardiography with CMR, compounded by differences in approaches to measuring deformation, and matching regional and slice measurements between techniques. Reproducibility (n = 10, including test-retest variability) of automated 3D strain and rotation measurements was good to excellent (coefficient of variation < 10%) and was comparable with that of CMR methods (coefficient of variation < 10%) in the same patients.

CONCLUSIONS

The data from this study show that automated measurements of voxel rotational mechanics by real-time volume transthoracic echocardiography is feasible and comparable with tagged CMR and feature-tracking CMR strain measurements, albeit with wide limits of agreement, emphasizing the differences between the modalities. Furthermore, this automated 3D speckle-tracking echocardiographic approach shows excellent reproducibility, including test-retest variability, comparable with that of the CMR methods.

Real Time Three-Dimensional Echocardiographic Evaluations of Fetal Left Ventricular Stroke Volume, Mass, and Myocardial Strain: In Vitro and In Vivo Experimental Study

BACKGROUND

Left ventricular stroke volume, mass, and myocardial strain are valuable indicators of fetal heart function. This study investigated the feasibility of nongated real time three-dimensional echocardiography (RT3DE) to determine fetal stroke volume (SV), left ventricular mass (LVM), and myocardial strain under different conditions.

METHODS

To evaluate fetal hearts, fetal-sized rabbit hearts were used in this study. The in vitro portion of this study was carried out using a balloon inserted into the LV of eight fresh rabbit hearts and driven by a calibrated pulsatile pump. RT3DE volumes were obtained at various pump-set SVs. The in vivo experiments in this study were performed on open-chest rabbits. RT3DE volumes were acquired at the following conditions: baseline, simulated hypervolemia, inferior vena cava (IVC) ligation, and ascending aorta (AAO) ligation. Displacement values and sonomicrometry data were used as references for RT3DE-derived SV, LVM, longitudinal strain (LS), and circumferential strain (CS).

RESULTS

Excellent correlations between RT3DE-derived values and reference values were demonstrated and accompanied by high coefficients of determination (R(2) ) for both in vitro and in vivo studies for SV, LVM, LS, and CS (in vitro: SV: R(2)  = 0.98; LVM: R(2)  = 0.97; LS: R(2)  = 0.87, CS: R(2)  = 0.80; in vivo: SV: R(2)  = 0.92; LVM: R(2)  = 0.98; LS: in vivo: R(2)  = 0.84; CS: in vivo: R(2)  = 0.76; all P < 0.05).

CONCLUSIONS

RT3DE is capable of quantifying the SV, LVM, and myocardial strain of fetal-sized hearts under different conditions. This nongated RT3DE may aid the evaluation of fetal cardiac function, providing a superior understanding of the progress of fetal heart disorders.

Evaluation of left ventricular function by three-dimensional speckle-tracking echocardiography in patients with myocardial bridging of the left anterior descending coronary artery

BACKGROUND

To understand the influence of myocardial bridging (MB) on left ventricular (LV) function, myocardial function was studied in patients with MB of the left anterior descending coronary artery (LAD) using three-dimensional speckle-tracking echocardiography (STE).

METHODS

Left anterior descending coronary artery MB was diagnosed by coronary angiography in 82 subjects. Patients were divided into three groups according to the percentage of systolic narrowing of the compressed segment: 30% to 49% was defined as group I (24 patients), 50% to 74% as group II (28 patients), and ≥75% as group III (30 patients). Thirty gender- and age-matched normal subjects were included as controls. Left ventricular myocardial deformation was estimated by three-dimensional STE.

RESULTS

Left ventricular ejection fractions were normal in all patients, but diastolic function was impaired in groups II and III (E/E' ratio, 9 ± 3 and 10 ± 3, respectively). The amplitudes of longitudinal strain (LS) and area strain (AS) of the LAD territory was significantly reduced in groups II and III compared with controls and group I (LS, -15 ± 2% and -12 ± 1% vs -19 ± 2% and -18 ± 2%; AS, -22 ± 2% and -13 ± 2% vs -33 ± 4% and -33 ± 3%; P < .0001), but the amplitudes of circumferential and radial strain showed no intergroup differences. Longitudinal strain and AS were significantly lower in patients with fractional flow reserve < 0.75 than in those with fractional flow reserve ≥ 0.75 (P < .0001), with relative preservation of circumferential and radial strain. The severity of LAD compression was significantly associated with AS and LS of the LAD territory (r = -0.92 and r = -0.84, respectively, P < .0001), but the correlations with circumferential and radial strain were modest (r = -0.36 and r = -0.32, respectively, P < .05).

CONCLUSIONS

With the increasing severity of systolic compression of the mural coronary artery, LV diastolic function and regional systolic deformation (AS and LS) of the MB perfusion territory were reduced. Three-dimensional STE can detect subtle myocardial dysfunction in patients with MB.

Prognostic value of LV deformation parameters using 2D and 3D speckle-tracking echocardiography in asymptomatic patients with severe aortic stenosis and preserved LV ejection fraction

OBJECTIVES

The objective of this study was to determine which strain component assessed by 2-dimensional speckle-tracking echocardiography (2DSTE) and 3-dimensional speckle-tracking echocardiography (3DSTE) was the most powerful predictor for future major adverse cardiac events (MACE) in asymptomatic patients with severe aortic stenosis (AS).

BACKGROUND

Ongoing debate exists regarding the appropriateness of early surgery in asymptomatic severe AS and preserved left ventricular ejection fraction (LVEF). Previous studies showed that 2-dimensional global longitudinal strain (2DGLS) was a significant predictor in asymptomatic severe AS patients. However, the prognostic utility of 3DSTE-derived multidirectional strain parameters has not been investigated in these patients.

METHODS

We enrolled 104 asymptomatic severe AS patients (indexed aortic valve area <0.6 cm(2)/m(2)) and preserved LVEF and performed strain analysis using both 2DSTE and 3DSTE. Two-dimensional and 3-dimensional global longitudinal, circumferential, and radial strain and global 3-dimensional strain were measured in each patient. All patients were followed to record MACE.

RESULTS

During a median follow-up of 373 days, MACE developed in 33 patients (32%). 2DGLS (-14.7 ± 3.3 vs. -16.3 ± 3.3, p = 0.0168), 3DGLS (-13.5 ± 2.5 vs. -16.1 ± 2.4, p < 0.0001) and 3-dimensional global radial strain (3DGRS) (35.9 ± 4.5 vs. 38.1 ± 4.4, p = 0.0209) were significantly impaired in patients with MACE compared with those without MACE. Kaplan-Meier analysis showed 2DGLS (cutoff: -17.0%), 3DGLS (cutoff: -14.5%), and 3DGRS (cutoff: 39.0%) provide a significant difference in MACE rate. Receiver-operating characteristic analysis revealed that the area under the curve of 3DGLS for MACE (0.78) was significantly larger than that of 2DGLS (0.62, p = 0.0044) and 3DGRS (0.66, p = 0.0069). Separate multivariate analysis revealed 3DGLS was only significant as independent predictor for future MACE after correcting for mean pressure gradient and left ventricular mass index.

CONCLUSIONS

3DGLS is the most robust index for predicting future adverse cardiac events in asymptomatic severe AS patients with preserved LVEF.

Structural and functional changes in maternal left ventricle during pregnancy: a three-dimensional speckle-tracking echocardiography study

Background

Pregnancy represents a physiological adaptation to the transient load changes of maternal heart. This study aimed to investigate maternal left ventricle (LV) performance during normal pregnancy by three-dimensional speckle-tracking echocardiography (3D STE) parameters considering LV loading and shape.

Methods

Sequential two-dimensional echocardiography (2DE) and 3D STE were performed on 68 women during each pregnancy trimester and 6 to 9 weeks after delivery, while thirty age-matched, healthy, nonpregnant women served as controls. Global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and global radial strain (GRS) were measured.

Results

Increased cardiac index and progressive eccentric hypertrophy was detected, which subsequently recovered postpartum. In late pregnancy, GLS, GCS, GAS and GRS significantly decreased (P < 0.05) accompanied by a slight reduction of LV ejection fraction (EF) (P < 0.05), and these values returned postpartum to baseline level. All 3D strain indices correlated well with gestation age (P < 0.01), while compared to other components, GAS exhibited the strongest association with 3D EF (r = 0.549) and sphericity index (r = 0.328), and was the only parameter that correlated well with LV mass index (r = 0.22).

Conclusions

This study gives normal ranges of 3D STE indices in pregnancy. 3D STE demonstrated modified myocardial deformation and changes in maternal LV structure and function during the gestation period.

Current status of 3-dimensional speckle tracking echocardiography: a review from our experiences

Cardiac function analysis is the main focus of echocardiography. Left ventricular ejection fraction (LVEF) has been the clinical standard, however, LVEF is not enough to investigate myocardial function. For the last decade, speckle tracking echocardiography (STE) has been the novel clinical tool for regional and global myocardial function analysis. However, 2-dimensional imaging methods have limitations in assessing 3-dimensional (3D) cardiac motion. In contrast, 3D echocardiography also has been widely used, in particular, to measure LV volume measurements and assess valvular diseases. Joining the technology bandwagon, 3D-STE was introduced in 2008. Experimental studies and clinical investigations revealed the reliability and feasibility of 3D-STE-derived data. In addition, 3D-STE provides a novel deformation parameter, area change ratio, which have the potential for more accurate assessment of overall and regional myocardial function. In this review, we introduced the features of the methodology, validation, and clinical application of 3D-STE based on our experiences for 7 years.