Three-Dimensional Principal Strain Analysis for Characterizing Subclinical Changes in Left Ventricular Function

Role of tissue biomechanics in the formation and function of myocardial trabeculae in zebrafish embryos

Cardiac trabeculae are uneven ventricular muscular structures that develop during early embryonic heart development at the outer curvature of the ventricle. Their biomechanical function is not completely understood, and while their formation is known to be mechanosensitive, it is unclear whether ventricular tissue internal stresses play an important role in their formation. Here, we performed imaging and image-based cardiac biomechanics simulations on zebrafish embryonic ventricles to investigate these issues. Microscopy-based ventricular strain measurements show that the appearance of trabeculae coincided with enhanced deformability of the ventricular wall. Image-based biomechanical simulations reveal that the presence of trabeculae reduces ventricular tissue internal stresses, likely acting as structural support in response to the geometry of the ventricle. Passive ventricular pressure-loading experiments further reveal that the formation of trabeculae is associated with a spatial homogenization of ventricular tissue stiffnesses in healthy hearts, but gata1 morphants with a disrupted trabeculation process retain a spatial stiffness heterogeneity. Our findings thus suggest that modulating ventricular wall deformability, stresses, and stiffness are among the biomechanical functions of trabeculae. Further, experiments with gata1 morphants reveal that a reduction in fluid pressures and consequently ventricular tissue internal stresses can disrupt trabeculation, but a subsequent restoration of ventricular tissue internal stresses via vasopressin rescues trabeculation, demonstrating that tissue stresses are important to trabeculae formation. Overall, we find that tissue biomechanics is important to the formation and function of embryonic heart trabeculation. KEY POINTS: Trabeculations are fascinating and important cardiac structures and their abnormalities are linked to embryonic demise. However, their function in the heart and their mechanobiological formation processes are not completely understood. Our imaging and modelling show that tissue biomechanics is the key here. We find that trabeculations enhance cardiac wall deformability, reduce fluid pressure stresses, homogenize wall stiffness, and have alignments that are optimal for providing load-bearing structural support for the heart. We further discover that high ventricular tissue internal stresses consequent to high fluid pressures are needed for trabeculation formation through a rescue experiment, demonstrating that myocardial tissue stresses are as important as fluid flow wall shear stresses for trabeculation formation.

Prognostic Utility of Cardiovascular Magnetic Resonance-Based Phenotyping in Patients With Muscular Dystrophy

Background The prognostic utility of cardiovascular magnetic resonance imaging, including strain analysis and tissue characterization, has not been comprehensively investigated in adult patients with muscular dystrophy. Methods and Results We prospectively enrolled 148 patients with dystrophinopathies (including heterozygotes), limb-girdle muscular dystrophy, and type 1 myotonic dystrophy (median age, 36.0 [interquartile range, 23.0-50.0] years; 51 [34.5%] women) over 7.7 years in addition to an age- and sex-matched healthy control cohort (n=50). Cardiovascular magnetic resonance markers, including 3-dimensional strain and fibrosis, were assessed for their respective association with major adverse cardiac events. Our results showed that markers of contractile performance were reduced across all muscular dystrophy groups. In particular, the dystrophinopathies cohort experienced reduced left ventricular (LV) ejection fraction and high burden of replacement fibrosis. Patients with type 1 myotonic dystrophy showed a 26.8% relative reduction in LV mass with corresponding reduction in chamber volumes. Eighty-two major adverse cardiac events occurred over a median follow-up of 5.2 years. Although LV ejection fraction was significantly associated with major adverse cardiac events (adjusted hazard ratio [aHR], 3.0 [95% CI, 1.4-6.4]) after adjusting for covariates, peak 3-dimensional strain amplitude demonstrated greater predictive value (minimum principal amplitude: aHR, 5.5 [95% CI, 2.5-11.9]; maximum principal amplitude: aHR, 3.3 [95% CI, 1.6-6.8]; circumferential amplitude: aHR, 3.4 [95% CI, 1.6-7.2]; longitudinal amplitude: aHR, 3.4 [95% CI, 1.7-6.9]; and radial strain amplitude: aHR, 3.0 [95% CI, 1.4-6.1]). Minimum principal strain yielded incremental prognostic value beyond LV ejection fraction for association with major adverse cardiac events (change in χ2=13.8; P<0.001). Conclusions Cardiac dysfunction is observed across all muscular dystrophy subtypes; however, the subtypes demonstrate distinct phenotypic profiles. Myocardial deformation analysis highlights unique markers of principal strain that improve risk assessment over other strain markers, LV ejection fraction, and late gadolinium enhancement in this vulnerable patient population.

Three-Dimensional, Right Ventricular Surface Strain Computation From Three-Dimensional Echocardiographic Images From Patients With Pediatric Pulmonary Hypertension

Right Ventricular (RV) dysfunction is routinely assessed with echocardiographic-derived global longitudinal strain (GLS). GLS is measured from a two-dimensional echo image and is increasingly accepted as a means for assessing RV function. However, any two-dimensional (2D) analysis cannot visualize the asymmetrical deformation of the RV nor visualize strain over the entire RV surface. We believe three-dimensional surface (3DS) strain, obtained from 3D echo will better evaluate myocardial mechanics. Components of 3DS strain (longitudinal, LS; circumferential, CS; longitudinal-circumferential shear, ɣCL; principal strains PSMax and PSMin; max shear, ɣMax; and principal angle θMax) were computed from RV surface meshes obtained with 3D echo from 50 children with associated pulmonary arterial hypertension (PAH), 43 children with idiopathic PAH, and 50 healthy children by computing strains from a discretized displacement field. All 3DS freewall (FW) normal strain (LS, CS, PSMax, and PSMin) showed significant decline at end-systole in PH groups (p < 0.0001 for all), as did FW-ɣMax (p = 0.0012). FW-θMax also changed in disease (p < 0.0001). Limits of agreement analysis suggest that 3DS LS, PSMax, and PSMin are related to GLS. 3DS strains showed significant heterogeneity over the 3D surface of the RV. Components of 3DS strain agree with existing clinical strain measures, well classify normal -versus- PAH subjects, and suggest that strains change direction on the myocardial surface due to disease. This last finding is similar to that of myocardial fiber realignment in disease, but further work is needed to establish true associations.

Clinical Usefulness of Speckle-Tracking Echocardiography in Patients with Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is defined as HF with left ventricular ejection fraction (LVEF) not less than 50%. HFpEF accounts for more than 50% of all HF patients, and its prevalence is increasing year to year with the aging population, with its prognosis worsening. The clinical assessment of cardiac function and prognosis in patients with HFpEF remains challenging due to the normal range of LVEF and the nonspecific symptoms and signs. In recent years, new echocardiographic techniques have been continuously developed, particularly speckle-tracking echocardiography (STE), which provides a sensitive and accurate method for the comprehensive assessment of cardiac function and prognosis in patients with HFpEF. Therefore, this article reviewed the clinical utility of STE in patients with HFpEF.

Strain estimation in aortic roots from 4D echocardiographic images using medial modeling and deformable registration

Even though the central role of mechanics in the cardiovascular system is widely recognized, estimating mechanical deformation and strains in-vivo remains an ongoing practical challenge. Herein, we present a semi-automated framework to estimate strains from four-dimensional (4D) echocardiographic images and apply it to the aortic roots of patients with normal trileaflet aortic valves (TAV) and congenital bicuspid aortic valves (BAV). The method is based on fully nonlinear shell-based kinematics, which divides the strains into in-plane (shear and dilatational) and out-of-plane components. The results indicate that, even for size-matched non-aneurysmal aortic roots, BAV patients experience larger regional shear strains in their aortic roots. This elevated strains might be a contributing factor to the higher risk of aneurysm development in BAV patients. The proposed framework is openly available and applicable to any tubular structures.

Does 3D-speckle tracking echocardiography improve prediction of major cardiovascular events in a multi-ethnic general population? A Southall and Brent Revisited (SABRE) cohort study

3D-speckle tracking echocardiography(3D-STE) allows simultaneous assessment of ejection fraction(EF) and multidirectional strains, but its prognostic utility in the general population is unknown. We investigated if 3D-STE strains predicted a composite of major cardiac endpoints(MACE) beyond cardiovascular risk factors(CVDRF), and whether they were superior to 3D-EF. 529 participants in SABRE, a UK-based tri-ethnic general population cohort (69±6y; 76.6% male) with acceptable 3D-STE imaging were studied. Associations between 3D-EF or multidirectional myocardial strains and MACE(coronary heart disease(fatal/non-fatal), heart failure hospitalization, new-onset arrhythmia and cardiovascular mortality) were determined using Cox regression including adjustment for CVDRF and 2D-EF. Whether 3D-EF, global longitudinal strain(3D-GLS) and principle tangential strain(3D-PTS/3D-strain) improved cardiovascular risk stratification over CVDRF was investigated using a likelihood ratio test on a series of nested Cox proportional hazards models and Harrell's C statistics. During follow-up(median, 12y), there were 92 events. 3D-EF, 3D-GLS and 3D-PTS and 3D-RS were associated with MACE in unadjusted and models adjusted for CVDRF but not CVDRF+2D-EF. Compared to 3D-EF, both 3D-GLS and 3D-PTS slightly improved the predictive value over CVDRF for MACE, but the improvement was modest(C statistic increased from 0.698(0.647, 0.749) to 0.715(0.663, 0.766) comparing CVDRF with CVDRF +3D-GLS). 3D-STE-derived LV myocardial strains predicted MACE in a multi-ethnic general population sample of elderly individuals from the UK; however the added prognostic value of 3D-STE myocardial strains was small.

Myocardial Biomechanics and the Consequent Differentially Expressed Genes of the Left Atrial Ligation Chick Embryonic Model of Hypoplastic Left Heart Syndrome

Left atrial ligation (LAL) of the chick embryonic heart is a model of the hypoplastic left heart syndrome (HLHS) where a purely mechanical intervention without genetic or pharmacological manipulation is employed to initiate cardiac malformation. It is thus a key model for understanding the biomechanical origins of HLHS. However, its myocardial mechanics and subsequent gene expressions are not well-understood. We performed finite element (FE) modeling and single-cell RNA sequencing to address this. 4D high-frequency ultrasound imaging of chick embryonic hearts at HH25 (ED 4.5) were obtained for both LAL and control. Motion tracking was performed to quantify strains. Image-based FE modeling was conducted, using the direction of the smallest strain eigenvector as the orientations of contractions, the Guccione active tension model and a Fung-type transversely isotropic passive stiffness model that was determined via micro-pipette aspiration. Single-cell RNA sequencing of left ventricle (LV) heart tissues was performed for normal and LAL embryos at HH30 (ED 6.5) and differentially expressed genes (DEG) were identified.After LAL, LV thickness increased by 33%, strains in the myofiber direction increased by 42%, while stresses in the myofiber direction decreased by 50%. These were likely related to the reduction in ventricular preload and underloading of the LV due to LAL. RNA-seq data revealed potentially related DEG in myocytes, including mechano-sensing genes (Cadherins, NOTCH1, etc.), myosin contractility genes (MLCK, MLCP, etc.), calcium signaling genes (PI3K, PMCA, etc.), and genes related to fibrosis and fibroelastosis (TGF-β, BMP, etc.). We elucidated the changes to the myocardial biomechanics brought by LAL and the corresponding changes to myocyte gene expressions. These data may be useful in identifying the mechanobiological pathways of HLHS.

3-Dimensional Strain Analysis of Hypertrophic Cardiomyopathy: Insights From the NHLBI International HCM Registry

BACKGROUND

Abnormal global longitudinal strain (GLS) has been independently associated with adverse cardiac outcomes in both obstructive and nonobstructive hypertrophic cardiomyopathy.

OBJECTIVES

The goal of this study was to understand predictors of abnormal GLS from baseline data from the National Heart, Lung, and Blood Institute (NHLBI) Hypertrophic Cardiomyopathy Registry (HCMR).

METHODS

The study evaluated comprehensive 3-dimensional left ventricular myocardial strain from cine cardiac magnetic resonance in 2,311 patients from HCMR using in-house validated feature-tracking software. These data were correlated with other imaging markers, serum biomarkers, and demographic variables.

RESULTS

Abnormal median GLS (> -11.0%) was associated with higher left ventricular (LV) mass index (93.8 ± 29.2 g/m2 vs 75.1 ± 19.7 g/m2; P < 0.0001) and maximal wall thickness (21.7 ± 5.2 mm vs 19.3 ± 4.1 mm; P < 0.0001), lower left (62% ± 9% vs 66% ± 7%; P < 0.0001) and right (68% ± 11% vs 69% ± 10%; P < 0.01) ventricular ejection fractions, lower left atrial emptying functions (P < 0.0001 for all), and higher presence and myocardial extent of late gadolinium enhancement (6 SD and visual quantification; P < 0.0001 for both). Elastic net regression showed that adjusted predictors of GLS included female sex, Black race, history of syncope, presence of systolic anterior motion of the mitral valve, reverse curvature and apical morphologies, LV ejection fraction, LV mass index, and both presence/extent of late gadolinium enhancement and baseline N-terminal pro-B-type natriuretic peptide and troponin levels.

CONCLUSIONS

Abnormal strain in hypertrophic cardiomyopathy is associated with other imaging and serum biomarkers of increased risk. Further follow-up of the HCMR cohort is needed to understand the independent relationship between LV strain and adverse cardiac outcomes in hypertrophic cardiomyopathy.

Elucidating the mechanisms underlying left ventricular function recovery in patients with ischemic heart failure undergoing surgical remodeling: A 3-dimensional ultrasound analysis

OBJECTIVE

The study objective was to elucidate the mechanisms of left ventricle functional recovery in terms of endocardial contractility and synchronicity after surgical ventricular reconstruction.

METHODS

Real-time 3-dimensional transthoracic echocardiography was performed on 20 patients with anterior left ventricle remodeling and ischemic heart failure before surgical ventricular reconstruction and at 6-month follow-up, and on 15 healthy controls matched by age and body surface area. Real-time 3-dimensional transthoracic echocardiography datasets were analyzed through TomTec software (4D LV-Analysis; TomTec Imaging Systems GmbH, Unterschleissheim, Germany): Left ventricle volumes, ejection fraction, and global longitudinal strain were computed; the time-dependent endocardial surface yielded by 3-dimensional speckle-tracking echocardiography was postprocessed through in-house software to quantify local systolic minimum principal strain as a measure of fiber shortening and mechanical dispersion as a measure of fiber synchronicity.

RESULTS

Compared with controls, patients with heart failure before surgical ventricular reconstruction showed lower ejection fraction (P < .0001) and significantly impaired mechanical dispersion (P < .0001) and minimum principal strain (P < .0001); the latter worsened progressively from left ventricle base to apex. After surgical ventricular reconstruction, global longitudinal strain improved from -6.7% to -11.3% (P < .0001); mechanical dispersion decreased in every left ventricle region (P ≤ .017) and mostly in the basal region, where computed mechanical dispersion values were comparable to physiologic values (P ≥ .046); minimum principal strain improved mostly in the basal region, changing from -16.6% to -22.3% (P = .0027).

CONCLUSIONS

At 6-month follow-up, surgical ventricular reconstruction was associated with significant recovery in global left ventricle function, improved mechanical dispersion indicating a more synchronous left ventricle contraction, and improved left ventricle fiber shortening mostly in the basal region, suggesting the major role of the remote myocardium in enhancing left ventricle functional recovery.

Normative healthy reference values for global and segmental 3D principal and geometry dependent strain from cine cardiac magnetic resonance imaging

3-Dimensional (3D) myocardial deformation analysis (3D-MDA) enables novel descriptions of geometry-independent principal strain (PS). Applied to routine 2D cine cardiovascular magnetic resonance (CMR), this provides unique measures of myocardial biomechanics for disease diagnosis and prognostication. However, healthy reference values remain undefined. This study describes age- and sex-stratified reference values from CMR-based 3D-MDA, including 3D PS. One hundred healthy volunteers were prospectively recruited following institutional ethics approval and underwent CMR imaging. 3D-MDA was performed using validated software. Age- and sex-stratified global and segmental strain measures were derived for conventional geometry-dependent [circumferential (CS), longitudinal (LS), and radial (RS)] and geometry-independent [minimum (minPS) and maximum principal (maxPS)] directions of deformation. Layer-specific contraction angle interactions were determined using local minPS vectors. The average age was 43 ± 15 years and 55% were women. Strain measures were higher in women versus men. 3D PS-based assessment of maximum tissue shortening (minPS) and maximum tissue thickening (maxPS) were greater than corresponding geometry-dependent markers of LS and RS, consistent with improved representation of local tissue deformations. Global maxPS amplitude best discriminated both age and sex. Segmental analyses showed greater strain amplitudes in apical segments. Transmural PS contraction angles were higher in females and showed a heterogeneous distribution across segments. In this study we provided age and sex-based reference values for 3D strain from CMR imaging, demonstrating improved capacity for 3D PS to document maximal local tissue deformations and to discriminate age and sex phenotypes. Novel markers of layer-specific strain angles from 3D PS were also described.

Real-time three-dimensional echocardiography for detection of cardiac sarcoidosis in the early stage: a cross-sectional single-centre study

BACKGROUND

Sarcoidosis with cardiac involvement has a relatively high morbidity and mortality, and early diagnose of cardiac sarcoidosis is a critical issue. Systolic dyssynchrony index (SDI) measured by three-dimensional echocardiography was used in our study for detection of subclinical left ventricular (LV) systolic dysfunction in patients with sarcoidosis and normal LV function on two-dimensional echocardiography.

METHODS

Forty-four patients diagnosed with sarcoidosis (without clinically apparent cardiac involvement) and 44 healthy control subjects were included in this study. Two-dimensional echocardiographic parameters, also LV volumes and SDI measured by 3D echocardiography were analyzed in all participants.

RESULTS

While two-dimensional echocardiographic results of both study groups were similar; SDI_16 (SDI for 16 segments of LV) results were significantly higher in sarcoidosis group compared to healthy controls (6.99 ±5.02 vs 2.89 ± 1.32, p < 0.0001).

CONCLUSION

SDI_16 was higher in patients with sarcoidosis compared to healthy controls probably due to patchy infiltration characteristic of the disease. This parameter could be used as a marker to identify patients with cardiac involvement of sarcoidosis in the early phase.

Mechanical dispersion combined with global longitudinal strain estimated by three dimensional speckle tracking in patients with ST elevation myocardial infarction

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LV mechanical dispersion is a measure of regional heterogeneity of myocardial contraction.

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LV mechanical dispersion has been reported as an important prognosticator in STEMI.

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3D speckle tracking enables us to precisely measure LV mechanical dispersion.

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LV mechanical dispersion by 3D speckle tracking can precisely predict prognosis.

Background

The role of left ventricular (LV) mechanical dispersion estimated after an ST elevation acute myocardial infarction (STEMI) remains unclear.

Methods

The study participants were 208 consecutive patients (152 men, age = 72 years) presenting with STEMI for the first time who underwent primary percutaneous coronary intervention (PCI) within 12 h of STEMI onset. Within 48 h of PCI (mean = 24 h), 2D and 3D speckle-tracking echocardiography were performed. The global longitudinal strain (GLS) was calculated using 3D (3D-GLS) and 2D (2D-GLS) speckle tracking. Mechanical dispersion was defined using the standard deviation (SD) of the time to regional peak longitudinal strain (LS) for all 16 segments for both 2D-STE and 3D-STE (2D-LS-SD, 3D-LS-SD). Infarct size was estimated by Tc99m-sestamibi as the total area of < 50% of the uptake area at 2 weeks. The patients were followed up for a longer period of time (median118months) and checked for major adverse cardiac events (MACE: cardiac death, heart failure).

Results

During follow-up, 55 patients experienced MACE. The cut-off values were determined using receiver operating characteristic curves. The multivariate analysis revealed that a 3D-LS-SD > 56.7 ms was a significant predictor of MACEs (hazard ratio = 1.991, 95% confidence interval 1.033–3.613, p = 0.03), but 2D-LS-SD > 58.1 ms was not an independent predictor of MACEs (hazard ratio = 1.577, 95% confidence interval 0.815–3.042, p = 0.1). Furthermore, the combination of 3D-GLS and 3D-LS-SD had accurate predictability for MACE, as shown by the Kaplan-Meier curves (log rank, χ² = 94.1, p < 0.0001).

Conclusions

LV mechanical dispersion besides 3D-GLS assessed by 3D-STE immediately after PCI can predict long-term prognosis.

Comparison of left ventricular subclinical systolic dysfunction between hemodialysis patients and renal transplant recipients using real time three-dimensional echocardiography

AIMS

The relationship between chronic kidney disease and development of heart failure is a well-known clinical entity. Systolic dyssynchrony index (SDI_16) is a new diagnostic tool for detection of subclinical left ventricular (LV) systolic dysfunction by using three-dimensional echocardiography (3DE). We aimed to investigate this parameter in patients with end-stage renal disease who were receiving hemodialysis and patients with renal transplant compared to healthy control subjects.

MATERIAL AND METHODS

Forty-five hemodialysis patients, 45 patients with renal transplant and 45 age-sex matched healthy control subjects included in the study. All participants were evaluated with 3DE in the interdialytic phase for measurement of LV volumes, ejection fraction and SDI_16 parameter.

RESULTS

Both LV diastolic and systolic volumes were significantly higher in hemodialysis group compared to renal transplant group and healthy controls, but this finding did not translate to a statistically significant difference for LVEF measurements between groups (58.71 ± 3.53 vs. 57.17 ± 2.97 vs. 59.23 ± 3.26, p = .16 for renal transplant and hemodialysis and healthy control groups, respectively). Mean value of SDI_16 parameters was significantly higher in hemodialysis group compared to renal transplant group (7.93 ± 2.50 vs. 3.72 ± 1.71, p < .001) and healthy controls (7.93 ± 2.50 vs. 3.00 ± .99, p < .001); whereas, it was similar between renal transplant group and control subjects (3.72 ± 1.71 vs. 3.00 ± .99, p = .10).

CONCLUSION

SDI_16 was significantly higher in hemodialysis patients compared to patients with renal transplant and healthy controls.

Morning blood pressure surge in the early stage of hypertensive patients impacts three-dimensional left ventricular speckle tracking echocardiography

BACKGROUND

The aim of this study was to examine left ventricular (LV) function in untreated, newly diagnosed hypertensive patients with morning blood pressure surge (MBPS) status using three-dimensional (3D) speckle tracking echocardiography (STE).

METHODS

In this study, 163 newly diagnosed hypertensive patients were included, and all patients underwent 24-h ambulatory blood pressure monitoring (ABPM). According to ABPM, participants were divided into a MBPS group and a non-MBPS group. The entire study population was examined by complete two-dimensional (2D) transthoracic echocardiography (TTE) and 3D STE.

RESULT

The results of this study showed that 3D LV longitudinal strain was significantly decreased in the MBPS group compared with the non-MBPS group (- 30.1 ± 2.0 vs. -31.1 ± 2.7, p = 0.045). Similar trends were observed for 3D twist (9.6 ± 6.1 vs. 12.1 ± 4.8, p = 0.011) as well as for 3D torsion (1.23 ± 0.78 vs. 1.49 ± 0.62, p = 0.042). The LV principal strain was decreased in the MBPS group (- 33.9 ± 1.7 vs. -35.5 ± 2.8, p < 0.001). The 3D LV global longitudinal strain (GLS) and principal strain were significantly associated with quartile of MBPS as measured by systolic blood pressure (SBP).

CONCLUSION

The 3D STE revealed that LV mechanics were more impaired in the MBPS group than in the non-surge newly diagnosed, untreated hypertensive patients; even the 2D TTE parameters showed no difference.

Global Strain Measured by Three-Dimensional Speckle Tracking Echocardiography Is a Useful Predictor for 10-Year Prognosis After a First ST-Elevation Acute Myocardial Infarction

BACKGROUND

Three-dimensional (3D) speckle tracking echocardiography (STE) after ST-elevation acute myocardial infarction (STEMI) is associated with left ventricular (LV) remodeling and 1-year prognosis. This study investigated the clinical significance of 3D-STE in predicting the long-term prognosis of patients with STEMI.Methods and Results:A total of 270 patients (mean age 64.6 years) with first-time STEMI treated with reperfusion therapy were enrolled. At 24 h after admission, standard 2D echocardiography and 3D full-volume imaging were performed, and 2D-STE and 3D-STE were calculated. Patients were followed up for a median of 119 months (interquartile range: 96-129 months). The primary endpoint was occurrence of a major adverse cardiac event (MACE: cardiac death, heart failure with hospitalization), and 64 patients experienced MACEs. Receiver operating characteristic curves and Cox hazard multivariate analysis showed that the 3D-STE indices were stronger predictors of MACE compared with those of 2D-STE. Additionally, 3D-global longitudinal strain (GLS) was the strongest predictor for MACE followed by 3D-global circumferential strain (GCS). The Kaplan-Meier curve demonstrated that 3D-GLS >-11.0 was an independent predictor for MACE (log-rank χ²=132.2, P<0.0001). When combined with 3D-GCS >-18.3, patients with higher values of 3D-GLS and 3D-GCS were found to be at extremely high risk for MACE.

CONCLUSIONS

Global strain measured by 3D-STE immediately after the onset of STEMI is a clinically significant predictor of 10-year prognosis.

Effect of Active Cancer on the Cardiac Phenotype: A Cardiac Magnetic Resonance Imaging-Based Study of Myocardial Tissue Health and Deformation in Patients With Chemotherapy-Naïve Cancer

Background

The overlap between cancer and cardiovascular care continues to expand, with intersections emerging before, during, and following cancer therapies. To date, emphasis has been placed on how cancer therapeutics influence downstream cardiac health. However, whether active malignancy itself influences chamber volumes, function, or overall myocardial tissue health remains uncertain. We sought to perform a comprehensive cardiovascular magnetic resonance‐based evaluation of cardiac health in patients with chemotherapy‐naïve cancer with comparison with a healthy volunteer population.

Methods and Results

Three‐hundred and eighty‐one patients with active breast cancer or lymphoma before cardiotoxic chemotherapy exposure were recruited in addition to 102 healthy volunteers. Both cohorts underwent standardized cardiovascular magnetic resonance imaging with quantification of chamber volumes, ejection fraction, and native myocardial T1. Left ventricular mechanics were incrementally assessed using three‐dimensional myocardial deformation analysis, providing global longitudinal, circumferential, radial, and principal peak‐systolic strain amplitude and systolic strain rate. The mean age of patients with cancer was 53.8±13.4 years; 79% being women. Despite similar left ventricular ejection fraction, patients with cancer showed smaller chambers, increased strain amplitude, and systolic strain rate in both conventional and principal directions, and elevated native T1 versus sex‐matched healthy volunteers. Adjusting for age, sex, hypertension, and diabetes mellitus, the presence of cancer remained associated with these cardiovascular magnetic resonance parameters.

Conclusions

The presence of cancer is independently associated with alterations in cardiac chamber size, function, and objective markers of tissue health. Dedicated research is warranted to elucidate pathophysiologic mechanisms underlying these findings and to explore their relevance to the management of patients with cancer referred for cardiotoxic therapies.

Left ventricular strain values using 3D speckle-tracking echocardiography in healthy adults aged 20 to 72 years

Three dimensional speckle tracking echocardiography (3D-STE) is a novel modality for the assessment of left ventricular strain (LVS). The aim of our study is to provide single vendor normative strain values measured with 3D-STE in healthy adult caucasians. One hundred fifty-five healthy subjects aged 20 to 72 years (≥ 28 subjects per decile) were prospectively included and examined with 2D and 3D transthoracic echocardiography. In 105 both 3D and 2D-STE were feasible (71%, mean age 44 ± 14 years, 51% female). Mean 3D tangential strain (3D-TS) was − 32 ± 2.9%. 3D global longitudinal strain (3D-GLS) demonstrated a significant but not very strong correlation with 2D-GLS values (− 19.7 ± 1.8% vs − 20.4 ± 2.2%, r = 0.462, p < 0.001). No gender difference was observed in 3D strain parameters. 3D-GLS decreased with increasing age stratum (p = 0.024). LVEF was associated with 3D-TS and 3D-GLS (r =  − 0.819, p ≤ 0.001 for 3D-TS, p =  − 0.477, r < 0.001, p = 0.001 for 3D-GLS). In this single vendor study age and gender-specific normative LV 3D-TS values were reported for healthy adult caucasians. In a significant proportion of the subjects 3D-STE was not feasible, but when feasible, 3D-STE shows excellent association with LVEF, and is therefore a promising novel modality for the assessment of the myocardial function, provided that issues of limited feasibility and temporal resolution are addressed.

Neural-Network-Based Diagnosis Using 3-Dimensional Myocardial Architecture and Deformation: Demonstration for the Differentiation of Hypertrophic Cardiomyopathy

The diagnosis of cardiomyopathy states may benefit from machine-learning (ML) based approaches, particularly to distinguish those states with similar phenotypic characteristics. Three-dimensional myocardial deformation analysis (3D-MDA) has been validated to provide standardized descriptors of myocardial architecture and deformation, and may therefore offer appropriate features for the training of ML-based diagnostic tools. We aimed to assess the feasibility of automated disease diagnosis using a neural network trained using 3D-MDA to discriminate hypertrophic cardiomyopathy (HCM) from its mimic states: cardiac amyloidosis (CA), Anderson–Fabry disease (AFD), and hypertensive cardiomyopathy (HTNcm). 3D-MDA data from 163 patients (mean age 53.1 ± 14.8 years; 68 females) with left ventricular hypertrophy (LVH) of known etiology was provided. Source imaging data was from cardiac magnetic resonance (CMR). Clinical diagnoses were as follows: 85 HCM, 30 HTNcm, 30 AFD, and 18 CA. A fully-connected-layer feed-forward neural was trained to distinguish HCM vs. other mimic states. Diagnostic performance was compared to threshold-based assessments of volumetric and strain-based CMR markers, in addition to baseline clinical patient characteristics. Threshold-based measures provided modest performance, the greatest area under the curve (AUC) being 0.70. Global strain parameters exhibited reduced performance, with AUC under 0.64. A neural network trained exclusively from 3D-MDA data achieved an AUC of 0.94 (sensitivity 0.92, specificity 0.90) when performing the same task. This study demonstrates that ML-based diagnosis of cardiomyopathy states performed exclusively from 3D-MDA is feasible and can distinguish HCM from mimic disease states. These findings suggest strong potential for computer-assisted diagnosis in clinical practice.

Phenotyping of hypertensive heart disease and hypertrophic cardiomyopathy using personalized 3D modelling and cardiac cine MRI

Differential diagnosis of hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM) is clinically challenging but important for treatment management. This study aims to phenotype HHD and HCM in 3D + time domain by using a multiparametric motion-corrected personalized modeling algorithm and cardiac magnetic resonance (CMR). 44 CMR data, including 12 healthy, 16 HHD and 16 HCM cases, were examined. Multiple CMR phenotype data consisting of geometric and dynamic variables were extracted globally and regionally from the models over a full cardiac cycle for comparison against healthy models and clinical reports. Statistical classifications were used to identify the distinctive characteristics and disease subtypes with overlapping functional data, providing insights into the challenges for differential diagnosis of both types of disease. While HCM is characterized by localized extreme hypertrophy of the LV, wall thickening/contraction/strain was found to be normal and in sync, though it was occasionally exaggerated at normotrophic/less severely hypertrophic regions during systole to preserve the overall ejection fraction (EF) and systolic functionality. Additionally, we observed that hypertrophy in HHD could also be localized, although at less extreme conditions (i.e. more concentric). While fibrosis occurs mostly in those HCM cases with aortic obstruction, only minority of HHD patients were found affected by fibrosis. We demonstrate that subgroups of HHD (i.e. preserved and reduced EF: HHDpEF & HHDrEF) have different 3D + time CMR characteristics. While HHDpEF has cardiac functions in normal range, dilation and heart failure are indicated in HHDrEF as reflected by low LV wall thickening/contraction/strain and synchrony, as well as much reduced EF.

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.

2- and 3-Dimensional Myocardial Strain in Cardiac Health and Disease

Advances in speckle-tracking echocardiography allowed the rise of deformation imaging as a feasible, robust, and valuable tool for clinical routine. The global or segmental measurement of strain can objectively quantify myocardial deformation and can characterize myocardial function in a novel way. However, the proper interpretation of deformation measurements requires understanding of cardiac mechanics and the influence of loading conditions, ventricular geometry, conduction delays, and myocardial tissue characteristics on the measured values. The purpose of this manuscript is to review the basic concepts of deformation imaging, briefly describe imaging modalities for strain assessment, and discuss in depth the underlying physical and pathophysiological mechanisms which lead to the respective findings in a specific disease.

3D Hermite Transform Optical Flow Estimation inLeft Ventricle CT Sequences

Heart diseases are the most important causes of death in the world and over the years, thestudy of cardiac movement has been carried out mainly in two dimensions, however, it is important toconsider that the deformations due to the movement of the heart occur in a three-dimensional space.The 3D + t analysis allows to describe most of the motions of the heart, for example, the twistingmotion that takes place on every beat cycle that allows us identifying abnormalities of the heartwalls. Therefore, it is necessary to develop algorithms that help specialists understand the cardiacmovement. In this work, we developed a new approach to determine the cardiac movement inthree dimensions using a differential optical flow approach in which we use the steered Hermitetransform (SHT) which allows us to decompose cardiac volumes taking advantage of it as a model ofthe human vision system (HVS). Our proposal was tested in complete cardiac computed tomography(CT) volumes ( 3D + t), as well as its respective left ventricular segmentation. The robustness tonoise was tested with good results. The evaluation of the results was carried out through errors inforwarding reconstruction, from the volume at time t to time t + 1 using the optical flow obtained(interpolation errors). The parameters were tuned extensively. In the case of the 2D algorithm, theinterpolation errors and normalized interpolation errors are very close and below the values reportedin ground truth flows. In the case of the 3D algorithm, the results were compared with another similarmethod in 3D and the interpolation errors remained below 0.1. These results of interpolation errorsfor complete cardiac volumes and the left ventricle are shown graphically for clarity. Finally, a seriesof graphs are observed where the characteristic of contraction and dilation of the left ventricle isevident through the representation of the 3D optical flow.

The value of left ventricular strain-volume loops in predicting response to cardiac resynchronization therapy

BACKGROUND

Three-dimensional (3D) speckle tracking imaging (STI) allows the simultaneous assessment of left ventricular (LV) strain and volume. We aim to explore the value of LV strain-volume loops in predicting response to cardiac resynchronization therapy (CRT).

METHODS

Forty heart failure (HF) patients scheduled for CRT and twenty healthy individuals were enrolled. All subjects received a 3D echocardiography and 3D STI analysis to acquire LV global and segmental principal strain (PS) and volume simultaneously. Values were plotted in a Cartesian system to construct PS-volume loop which was assessed using the two characteristics of the linear fitting curve: the slope and the coefficient of determination (R²-S/D coupling).

RESULTS

HF patients at baseline showed significantly lower slope and R²-S/D coupling of all PS-volume loops than healthy subjects. As for as comparing Segmental PS-Global volume loop at baseline, Midseptal R²-S/D coupling was lower and Midlateral slope was higher in CRT responders than in non-responders. For each individual, the abnormal segmental heterogeneity of Midseptal slope and R²-S/D coupling were lower than Midlateral was observed only in responders. At follow-up, significant improvements of the Midseptal slope and R²-S/D coupling were observed in responders. Midseptal R²-S/D coupling at baseline was an independent predictor of CRT response and the cut-off value of 0.55 was recommended with sensitivity of 89% and specificity of 77%.

CONCLUSIONS

Analysis of strain-volume loops could provide unique information for predicting response to CRT. Assessment of septal myocardial wasted work at baseline is helpful to improve patient selection for CRT.

Strain measurement on four-dimensional dynamic-ventilation CT: quantitative analysis of abnormal respiratory deformation of the lung in COPD

Purpose

Strain measurement is frequently used to assess myocardial motion in cardiac imaging. This study aimed to apply strain measurement to pulmonary motion observed by four-dimensional dynamic-ventilation computed tomography (CT) and to clarify motion abnormality in COPD.

Materials and methods

Thirty-two smokers, including ten with COPD, underwent dynamic-ventilation CT during spontaneous breathing. CT data were continuously reconstructed every 0.5 seconds. In the series of images obtained by dynamic-ventilation CT, five expiratory frames were identified starting from the peak inspiratory frame (first expiratory frame) and ending with the fifth expiratory frame. Strain measurement of the scanned lung was performed using research software that was originally developed for cardiac strain measurement and modified for assessing deformation of the lung. The measured strain values were divided by the change in mean lung density to adjust for the degree of expiration. Spearman’s rank correlation analysis was used to evaluate associations between the adjusted strain measurements and various spirometric values.

Results

The adjusted strain measurement was negatively correlated with FEV₁/FVC (ρ=−0.52, P<0.01), maximum mid-expiratory flow (ρ=−0.59, P<0.001), and peak expiratory flow (ρ=−0.48, P<0.01), suggesting that abnormal deformation of lung motion is related to various patterns of expiratory airflow limitation.

Conclusion

Abnormal deformation of lung motion exists in COPD patients and can be quantitatively assessed by strain measurement using dynamic-ventilation CT. This technique can be expanded to dynamic-ventilation CT in patients with various lung and airway diseases that cause abnormal pulmonary motion.

Characterization of Right Ventricular Deformation in Pulmonary Arterial Hypertension Using Three-Dimensional Principal Strain Analysis

BACKGROUND

Pulmonary arterial hypertension (PAH) can cause maladaptive right ventricular (RV) functional changes associated with adverse prognosis that are challenging to accurately quantify noninvasively. The aim of this study was to explore principal strain (PS) with contraction angle analysis using three-dimensional echocardiography to characterize RV deformation changes in patients with PAH.

METHODS

Three-dimensional echocardiography was performed in 37 patients with PAH and 20 healthy control subjects with two-component (primary and secondary) PS and principal contraction angle analysis. Patients were stratified according to World Health Organization (WHO) functional class.

RESULTS

Primary PS differed significantly between patients with PAH and healthy control subjects (-20.2 ± 3.3% vs -26.8 ± 3.3%, P = .01), while secondary PS was not significantly different (3.6 ± 5.1% vs -2.5 ± 4.7%, P = .12). Principal contraction angle was significantly lower in patients with PAH (63 ± 22° vs 71 ± 7°, P = .01), with the greatest reduction for the RV free wall. Primary PS and principal contraction angle differed significantly between WHO class I and II and class III and IV patients (-23.9 ± 4.7% vs -18.1 ± 4.8% [P = .03] and 69 ± 9° vs 58 ± 14° [P = .03], respectively), while secondary PS was not significantly different between groups (P = .13). Compared with healthy control subjects, septal principal contraction angle was not different in patients with WHO class I and II PAH (P = .62), but it was significantly reduced in those with WHO class III and IV PAH (P < .01). The area under the curve for primary PS to differentiate patients with PAH by WHO functional class was 0.81 (95% CI, 0.77-0.89; P = .01). Primary PS intraclass correlation coefficients for intraobserver and interobserver variability were 0.91 (95% CI, 0.88-0.93) and 0.86 (95% CI, 0.81-0.88), respectively.

CONCLUSIONS

PS analysis using three-dimensional echocardiography provides comprehensive quantification of RV deformation and characterizes alterations occurring in PAH that are associated with WHO functional class.

2D/3D CMR tissue tracking versus CMR tagging in the assessment of spontaneous T2DM rhesus monkeys with isolated diastolic dysfunction

BACKGROUND

Spontaneous T2DM in rhesus monkeys manifests as isolated diastolic dysfunction in the early stage of diabetic cardiomyopathy, similar to humans. Myocardial deformation measurements have emerged as a superior way to measure left ventricular (LV) function in the early stage of cardiac dysfunction, making it possible to further evaluate early-stage LV dysfunction in spontaneous T2DM rhesus monkeys.

METHODS

Spontaneous T2DM rhesus monkeys with isolated diastolic dysfunction (T2DM-DD, n = 10) and corresponding nondiabetic healthy animals (ND, n = 9) were prospectively scanned for a CMR study. Circumferential and longitudinal peak systolic strain (Ecc, Ell), time to peak strain (tEcc, tEll) and peak diastolic strain rate (CSR, LSR) obtained from 2D/3D CMR-TT were compared with those obtained from CMR tagging separately. In addition, all CMR imaging protocols were performed twice in 9 ND animals to assess test-retest reproducibility.

RESULTS

Compared with the ND group, the T2DM-DD monkeys demonstrated significantly impaired LV Ecc (- 10.63 ± 3.23 vs - 14.18 ± 3.19, p < 0.05), CSR (65.50 ± 14.48 vs 65.50 ± 14.48, p < 0.01), Ell (- 9.11 ± 2.59 vs - 14.17 ± 1.68, p < 0.05), and LSR (59.43 ± 19.17 vs 108.46 ± 22.33, p < 0.01) with the tagging. Only Ecc (- 13.10 ± 2.47 vs - 19.03 ± 3.69, p < 0.01) and CSR (148.90 ± 31.27 vs 202.00 ± 51.88, p < 0.01) were significantly reduced with 2D CMR-TT, and only Ecc (- 13.77 ± 1.98 vs - 17.26 ± 3.78, p < 0.05) was significantly reduced with 3D CMR-TT. Moreover, 2D/3D CMR-TT-derived Ecc and CSR correlated with the corresponding tagging values collectively, with a statistically significant ICC value (p < 0.05). Test-retest repeatability analysis showed that most tagging-derived biomarkers had acceptable repeatability (p < 0.01). In addition, 2D CMR-TT-derived indicators were poorer than those derived from the tagging method but better than those obtained using the 3D method, with larger ICCs except for tEcc (p < 0.05).

CONCLUSIONS

LV systolic and diastolic deformations were impaired in spontaneous T2DM rhesus monkeys previously diagnosed with isolated diastolic dysfunction by echocardiography. The 2D CMR-TT-derived Ecc and CSR were effective in the evaluation of the myocardial systolic and diastolic functions of early-diabetic cardiomyopathy, with relatively higher test-retest reproducibility and acceptable correlation with the tagging method compared with the 3D CMR-TT method.

Identification of significant coronary artery disease in patients with non-ST segment elevation acute coronary syndrome by myocardial strain analyses using three dimensional speckle tracking echocardiography

BACKGROUND

Speckle-tracking imaging is a novel method for assessing left ventricular function and ischemic changes. This study aimed to predict the presence of significant coronary artery stenosis in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) by 3D strain analysis using speckle tracking echocardiography (3DSTE) at rest.

METHODS

This cross-sectional study included a total 60 patients with NSTE-ACS who underwent 3DSTE immediately prior to coronary angiography. Subsequently, patients undergone coronary angiogram (CAG) and divided into two groups; group- I: significant stenosis (n = 36), group-II: non-significant stenosis (n = 24).

RESULTS

Global peak systolic longitudinal strain (GPSLS), circumferential strain (CS), area strain (AS), and radial strain (RS) were obtained successfully in 60 patients. All strain parameters were significantly reduced in patient group of significant stenosis. Receiver operating characteristic (ROC) curve analysis demonstrated that GPSLS could effectively detect patients with significant stenosis (area under ROC curve = 0.840, 95% CI = 0.735-0.945). GPSLS with a cutoff value of -13.50% showed good sensitivity and specificity for predicting significant stenosis (sensitivity 88.9% and specificity 70.8%).

CONCLUSION

Global peak systolic longitudinal strain using 3D speckle tracking echocardiography at rest was significantly lower in patients with significant stenosis and might be useful for identifying patients with a significant stenosis with good degree of sensitivity and specificity.

Comprehensive assessment of left ventricular myocardial function by two-dimensional speckle-tracking echocardiography

Background

Left ventricular ejection fraction (LVEF) results from the combined action of longitudinal and circumferential contraction, radial thickening, and basal and apical rotation. The study of these parameters together may lead to an accurate assessment of the cardiac function.

Methods

Ninety healthy volunteers, categorized by gender and age (≤ 55 and >  55 years), were evaluated using two-dimensional speckle tracking echocardiography. Transversal views of the left ventricle (LV) were obtained to calculate circumferential strain and left ventricular twist, while three apical views were obtained to determine longitudinal strain (LS) and mitral annular plane systolic excursion (MAPSE). We established the integral myocardial function of the LV according to: 1. The Combined Deformation Parameter (CDP), which includes Deformation Product (DP) - Twist x LS (° x %) - and Deformation Index (DefI) -Twist / LS (° / %)-; and 2. the Torsion Index (TorI): Twist / MAPSE (° / cm).

Results

The mean age of our patients was 50.3 ± 11.1 years. CDP did not vary with gender or age. The average DP was − 432 ± 172 ° x %, and the average DefI was − 0.96 ± 0.36 ° / %. DP provides information about myocardial function (normal, pseudonormal, depressed), and the DefI quotient indicates which component (s) is/are affected in cases of abnormality. TorI was higher in volunteers over 55 years (16.5 ± 15.2 vs 13.1 ± 5.0 °/cm, p = 0.003), but did not vary with gender.

Conclusions

The proposed parameters integrate values of twisting and longitudinal shortening. They allow a complete physiological assessment of cardiac systolic function, and could be used for the early detection and characterization of its alteration.

Construction and Validation of Subject-Specific Biventricular Finite-Element Models of Healthy and Failing Swine Hearts From High-Resolution DT-MRI

Predictive computational modeling has revolutionized classical engineering disciplines and is in the process of transforming cardiovascular research. This is particularly relevant for investigating emergent therapies for heart failure, which remains a leading cause of death globally. The creation of subject-specific biventricular computational cardiac models has been a long-term endeavor within the biomedical engineering community. Using high resolution (0.3 × 0.3 × 0.8 mm) ex vivo data, we constructed a precise fully subject-specific biventricular finite-element model of healthy and failing swine hearts. Each model includes fully subject-specific geometries, myofiber architecture and, in the case of the failing heart, fibrotic tissue distribution. Passive and active material properties are prescribed using hyperelastic strain energy functions that define a nearly incompressible, orthotropic material capable of contractile function. These materials were calibrated using a sophisticated multistep approach to match orthotropic tri-axial shear data as well as subject-specific hemodynamic ventricular targets for pressure and volume to ensure realistic cardiac function. Each mechanically beating heart is coupled with a lumped-parameter representation of the circulatory system, allowing for a closed-loop definition of cardiovascular flow. The circulatory model incorporates unidirectional fluid exchanges driven by pressure gradients of the model, which in turn are driven by the mechanically beating heart. This creates a computationally meaningful representation of the dynamic beating of the heart coupled with the circulatory system. Each model was calibrated using subject-specific experimental data and compared with independent in vivo strain data obtained from echocardiography. Our methods produced highly detailed representations of swine hearts that function mechanically in a remarkably similar manner to the in vivo subject-specific strains on a global and regional comparison. The degree of subject-specificity included in the models represents a milestone for modeling efforts that captures realism of the whole heart. This study establishes a foundation for future computational studies that can apply these validated methods to advance cardiac mechanics research.

Three-dimensional thoracic aorta principal strain analysis from routine ECG-gated computerized tomography: feasibility in patients undergoing transcatheter aortic valve replacement

BACKGROUND

Functional impairment of the aorta is a recognized complication of aortic and aortic valve disease. Aortic strain measurement provides effective quantification of mechanical aortic function, and 3-dimenional (3D) approaches may be desirable for serial evaluation. Computerized tomographic angiography (CTA) is routinely performed for various clinical indications, and offers the unique potential to study 3D aortic deformation. We sought to investigate the feasibility of performing 3D aortic strain analysis in a candidate population of patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Twenty-one patients with severe aortic valve stenosis (AS) referred for TAVR underwent ECG-gated CTA and echocardiography. CTA images were analyzed using a 3D feature-tracking based technique to construct a dynamic aortic mesh model to perform peak principal strain amplitude (PPSA) analysis. Segmental strain values were correlated against clinical, hemodynamic and echocardiographic variables. Reproducibility analysis was performed.

RESULTS

The mean patient age was 81±6 years. Mean left ventricular ejection fraction was 52±14%, aortic valve area (AVA) 0.6±0.3 cm² and mean AS pressure gradient (MG) 44±11 mmHg. CTA-based 3D PPSA analysis was feasible in all subjects. Mean PPSA values for the global thoracic aorta, ascending aorta, aortic arch and descending aorta segments were 6.5±3.0, 10.2±6.0, 6.1±2.9 and 3.3±1.7%, respectively. 3D PSSA values demonstrated significantly more impairment with measures of worsening AS severity, including AVA and MG for the global thoracic aorta and ascending segment (p<0.001 for all). 3D PSSA was independently associated with AVA by multivariable modelling. Coefficients of variation for intra- and inter-observer variability were 5.8 and 7.2%, respectively.

CONCLUSIONS

Three-dimensional aortic PPSA analysis is clinically feasible from routine ECG-gated CTA. Appropriate reductions in PSSA were identified with increasing AS hemodynamic severity. Expanded study of 3D aortic PSSA for patients with various forms of aortic disease is warranted.

Left Ventricular Strain in Chemotherapy-Naive and Radiotherapy-Naive Patients With Cancer

BACKGROUND

We sought to investigate left ventricular (LV) function and mechanics in patients with cancer before they received chemotherapy or radiotherapy, as well as the relationship between cancer and reduced LV multidirectional strain in the whole study population.

METHODS

The retrospective study involved 122 chemotherapy- and radiotherapy-naive patients with cancer and 45 age- and sex-matched controls with a cardiovascular risk profile similar to that of the patients with cancer. All the patients underwent echocardiographic examination before introduction of chemotherapy or radiotherapy.

RESULTS

LV longitudinal (-19.1% ± 2.1% vs -17.8% ± 3.5%; P = 0.022), circumferential (-22.9% ± 3.5% vs -20.1% ± 4.1%; P < 0.001), and radial (40.5% ± 8.8% vs 35.2% ± 10.7%; P = 0.004) strain was significantly lower in the patients with cancer than in the control group. Endocardial and midmyocardial longitudinal LV strain was significantly reduced in the patients with cancer compared with the controls, whereas epicardial longitudinal strain was similar between these groups. Endocardial, midmyocardial, and epicardial circumferential strain was significantly lower in the chemotherapy- or radiotherapy-naive patients with cancer than in the controls. Cancer was associated with reduced longitudinal (odds ratio [OR], 9.0; 95% confidence interval [CI], 2.20-23.50; P < 0.001), reduced circumferential (OR, 7.1; 95% CI, 3.80-20.40; P < 0.001), and reduced radial strain (OR, 7.2; 95% CI, 3.41-25.10; P < 0.001) independent of age, sex, body mass index, diabetes, and hypertension.

CONCLUSIONS

LV mechanics was impaired in the patients with cancer compared with the controls even before initiation of chemotherapy and radiotherapy. Cancer and hypertension were associated with reduced LV multidirectional strain independent of other clinical parameters. The present results indicate that cancer itself potentially induces cardiac remodelling independent of chemotherapy and radiotherapy.

The impact of preload on 3-dimensional deformation parameters: principal strain, twist and torsion

Background

Strain analysis is feasible using three-dimensional (3D) echocardiography. This approach provides various parameters based on speckle tracking analysis from one full-volume image of the left ventricle; however, evidence for its volume independence is still lacking.

Methods

Fifty-eight subjects who were examined by transthoracic echocardiography immediately before and after hemodialysis (HD) were enrolled. Real-time full-volume 3D echocardiographic images were acquired and analyzed using dedicated software. Two-dimensional (2D) longitudinal strain (LS) was also measured for comparison with 3D strain values.

Results

Longitudinal (pre-HD: −24.57 ± 2.51, post-HD: −21.42 ± 2.15, P < 0.001); circumferential (pre-HD: −33.35 ± 3.50, post-HD: −30.90 ± 3.22, P < 0.001); and radial strain (pre-HD: 46.47 ± 4.27, post-HD: 42.90 ± 3.61, P < 0.001) values were significantly decreased after HD. The values of 3D principal strain (PS), a unique parameter of 3D images, were affected by acute preload changes (pre-HD: −38.10 ± 3.71, post-HD: −35.33 ± 3.22, P < 0.001). Twist and torsion values were decreased after HD (pre-HD: 17.69 ± 7.80, post-HD: 13.34 ± 6.92, P < 0.001; and pre-HD: 2.04 ± 0.86, post-HD:1.59 ± 0.80, respectively, P < 0.001). The 2D LS values correlated with the 3D LS and PS values.

Conclusion

Various parameters representing left ventricular mechanics were easily acquired from 3D echocardiographic images; however, like conventional parameters, they were affected by acute preload changes. Therefore, strain values from 3D echocardiography should be interpreted with caution while considering the preload conditions of the patients.

Clinical feasibility and validation of 3D principal strain analysis from cine MRI: comparison to 2D strain by MRI and 3D speckle tracking echocardiography

Two-dimensional (2D) strain analysis is constrained by geometry-dependent reference directions of deformation (i.e. radial, circumferential, and longitudinal) following the assumption of cylindrical chamber architecture. Three-dimensional (3D) principal strain analysis may overcome such limitations by referencing intrinsic (i.e. principal) directions of deformation. This study aimed to demonstrate clinical feasibility of 3D principal strain analysis from routine 2D cine MRI with validation to strain from 2D tagged cine analysis and 3D speckle tracking echocardiography. Thirty-one patients undergoing cardiac MRI were studied. 3D strain was measured from routine, multi-planar 2D cine SSFP images using custom software designed to apply 4D deformation fields to 3D cardiac models to derive principal strain. Comparisons of strain estimates versus those by 2D tagged cine, 2D non-tagged cine (feature tracking), and 3D speckle tracking echocardiography (STE) were performed. Mean age was 51 ± 14 (36% female). Mean LV ejection fraction was 66 ± 10% (range 37–80%). 3D principal strain analysis was feasible in all subjects and showed high inter- and intra-observer reproducibility (ICC range 0.83–0.97 and 0.83–0.98, respectively—p < 0.001 for all directions). Strong correlations of minimum and maximum principal strain were respectively observed versus the following: 3D STE estimates of longitudinal (r = 0.81 and r = −0.64), circumferential (r = 0.76 and r = −0.58) and radial (r = −0.80 and r = 0.63) strain (p < 0.001 for all); 2D tagged cine estimates of longitudinal (r = 0.81 and r = −0.81), circumferential (r = 0.87 and r = −0.85), and radial (r = −0.76 and r = 0.81) strain (p < 0.0001 for all); and 2D cine (feature tracking) estimates of longitudinal (r = 0.85 and −0.83), circumferential (r = 0.88 and r = −0.87), and radial strain (r = −0.79 and r = 0.84, p < 0.0001 for all). 3D principal strain analysis is feasible using routine, multi-planar 2D cine MRI and shows high reproducibility with strong correlations to 2D conventional strain analysis and 3D STE-based analysis. Given its independence from geometry-related directions of deformation this technique may offer unique benefit for the detection and prognostication of myocardial disease, and warrants expanded investigation.

Speckle tracking echocardiography in the critically ill: enticing research with minimal clinical practicality or the answer to non-invasive cardiac assessment?

Echocardiography is developing rapidly. Speckle tracking echocardiography is the latest semi-automatic tool that has potential to quantitatively describe cardiac dysfunction that may be unrecognised by conventional echocardiography. It is a non-Doppler, angle-independent, feasible and reproducible method to evaluate myocardial function in both non-critically ill and critically ill populations. Increasingly it has become a standard measure of both left and right ventricle function in specific patient groups, e.g. chemotherapy-induced cardiomyopathy or pulmonary hypertension. To date there are few studies in the critically ill, predominantly in sepsis, yet all describe dysfunction beyond standard measures. Other areas of interest include heart-lung interactions, right ventricle function and twist and torsion of the heart. A word of caution is required, however, in that speckle tracking echocardiography is far from perfect and is more challenging, particularly in the critically ill, than implied by many published studies. It takes time to learn and perform and most values are not validated, particularly in the critically ill. We should be cautious in accepting that the latest software used in cardiology cohorts will automatically be the answer in the critically ill. Even with these limitations the technology is enticing and results fascinating. We are uncovering previously undescribed dysfunction and although it currently is essentially a research-based activity, there is great promise as a clinical tool as echocardiography analysis becomes more automated, and potentially speckle tracking echocardiography could help describe cardiac function in critical illness more accurately than is possible with current techniques.

Management and control of isotonic contraction generated stress: evaluation of masseter muscle deformation pattern by means of ecography

PURPOSE

The objective of the following study is to observe the behavior of the six layers of the masseter during an isometric contraction at maximum exertion with the deformation pattern analysis method.

MATERIALS AND METHODS

This study has been conducted by use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5-12 MHz 40 mm) which allowed us to record a video (DCM) comprised of 45 frames per second. The probe was fixed to a brace and the patient was asked to clench their teeth as hard as possible, obtain the muscle's maximum exertion, for 5 seconds three times, with 30 seconds intervals in between. Both right and left masseter muscles were analyzed. Then we applied to the resulting video a software (Mudy 1.7.7.2 AMID Sulmona Italy) for the analysis of muscle deformation patterns (contraction, dilatation, cross-plane, vertical strain, horizontal strain, vertical shear, horizontal shear, horizontal displacement, vertical displacement). The number of videos of masseter muscles in contraction at maximum exertion due to dental clenching made during this research is around 12,000. Out of these we chose 1,200 videos which examine 200 patients (100 females, 100 males).

RESULTS

The analysis of the deformation patterns of the masseter allows us to observe how the six layers of the muscle have different and specific functions each, which vary depending on the applied force (application point, magnitude and direction) so that we find it impossible to assign to one of the three sections of the muscle a mechanical predominance. Therefore it appears that the three parts of the muscle have specific and synergistic tasks.

Ultrasound and analysis of the deformation patterns of the masseter muscle: comparing surgical anatomy, ultrasound and functional anatomy

PURPOSE

We have tried to demonstrate whether the analysis of the muscle strain allows us to identify the three distinct functional areas of the architecture of the masseter, as one would see them by performing or viewing an anatomical dissection of said muscle, and whether these sections have behave differently in terms of origin and coping of the strain they face (quantitative analysis).

MATERIALS AND METHODS

This work has been elaborated by the use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5-12 MHz 40 mm) which allowed us to record a 45 frame per second video (DCM). Videos has been elaborated by use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5-12 MHz 40 mm) which allowed us to record a 45 frame per second video (DCM). We applied to the resulting video a software (Mudy 1.7.7.2 AMID Sulmona Italy) for the analysis of muscle deformation patters (contraction, dilatation, cross-plane, vertical strain, horizontal strain, vertical shear, horizontal shear, horizontal displacement, vertical displacement). The number of videos of masseter muscles in contraction at maximum exertion due to dental clenching made during this research is around 12,000. Out of these we chose 1,200 videos which examine 200 patients (100 females, 100 males).

RESULTS

The deformation pattern analysis of the skeletal muscle on ultrasound basis seems to be an adequate instrument to use during the investigation of the functional structure of the masseter muscle given its ability to highlight the distinct activity of each separate part of the muscle.

CONCLUSIONS

Moreover the strain does not apply to the muscle uniformly; instead it varies according to the observed area.

Cardiac Magnetic Resonance Feature Tracking Biventricular Two-Dimensional and Three-Dimensional Strains to Evaluate Ventricular Function in Children After Repaired Tetralogy of Fallot as Compared with Healthy Children

Cardiac magnetic resonance imaging is an important tool to evaluate cardiac anatomy and ventricular size and function after repaired tetralogy of Fallot. Magnetic resonance tissue tagging is the gold standard for evaluation of myocardial strain. However, myocardial tagging strain requires tagged images to be obtained prospectively, during the scan and with limited temporal resolution. Cardiac magnetic resonance feature tracking is a new tool that allows the retrospective analysis of cine images. There is limited experience with cardiac magnetic resonance feature tracking strain analysis in children. The medical records of patients with repaired tetralogy of Fallot that had a cardiac magnetic resonance (CMR) study from December 2013 to June 2015 were reviewed. The control group included patients who underwent a CMR with normal cardiac anatomy and ventricular function. Global longitudinal, circumferential and radial strain parameters (2D and 3D) were obtained by retrospectively contouring cine images from ventricular short axis, two chamber and four chamber views using post-processing software (Circle CVi⁴², Calgary, Canada). The correlation between conventional ventricular function parameters and ventricular strain was performed using Pearson's correlation. The mean age of tetralogy of Fallot and control subjects was 12.4 and 14.1 years, respectively. In patients after repaired tetralogy of Fallot, the mean left ventricular global 2D and 3D circumferential strains were -17.4 ± 2.9 and -10.1 ± 3, respectively. The mean indexed right ventricular end-diastolic volume was 135.4 cc m² ± 46 compared to 75.7 cc m² ± 17 in control subjects (P = 0.0001, CI 95%). Left ventricular global circumferential 3D strain showed a statistically significant difference in patients after TOF repair compared to normal subjects (-10.1 ± 3 vs. -14.71 ± 1.9, P = 0.00001). A strong correlation between left ventricular global circumferential 3D strain and right ventricular end-diastolic volume (P ≤ 0.0001) was noted. We found a strong correlation between left ventricular circumferential 3D strain and indexed right ventricular end-diastolic volume, as well as a strong correlation between left ventricular longitudinal 2D strain and right ventricular ejection fraction. Circumferential 3D strain may be a suitable tool to detect early abnormalities of ventricular myocardium even before the ejection fraction becomes compromised. Large-scale prospective studies are recommended.

Assessment of left ventricular function in chronic alcoholics by real-time three-dimensional echocardiography

Chronic alcohol consumption may lead to progressive cardiac dysfunction. The aim of this study was to evaluate the feasibility of using real-time 3-dimensional echocardiography (3DE) on assessing left ventricular (LV) function in chronic alcoholics.We classified 92 male alcoholics into mild, moderate, and severe groups; 30 age-matched controls were also recruited. LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV ejection fraction (LVEF), LV mass (LVM), LV mass index (LVMI), and systolic dyssynchrony index (SDI) were measured by 3DE and 2-dimensional echocardiography (2DE).Compared to the control group, LV volume and mass were higher in the moderate and severe alcoholic groups (P < 0.05). The severe alcoholic (symptomatic) group demonstrated decreased LVEF and increased SDI (detected by 3DE) (P < 0.05).Real-time 3DE can detect the increases of LV volumes and mass in asymptomatic alcoholics, and the changes of LVEF and systolic synchrony index in symptomatic alcoholics.

Tissue Tracking Technology for Assessing Cardiac Mechanics: Principles, Normal Values, and Clinical Applications

Tissue tracking technologies such as speckle tracking echocardiography and feature tracking cardiac magnetic resonance have enhanced the noninvasive assessment of myocardial deformation in clinical research and clinical practice. The widespread enthusiasm for using tissue tracking techniques in research and clinical practice stems from the ready applicability of these technologies to routine echocardiographic or cardiac magnetic resonance images. The technology is common to both modalities, and derived parameters to describe myocardial mechanics are the similar, albeit with different accuracies. We provide an overview of the normal values and reproducibility of the clinically applicable parameters, together with their clinical validation. The use of these technologies in different clinical scenarios, and the additive value to current imaging diagnostics are discussed.

Principles of cardiovascular magnetic resonance feature tracking and echocardiographic speckle tracking for informed clinical use

Tissue tracking technology of routinely acquired cardiovascular magnetic resonance (CMR) cine acquisitions has increased the apparent ease and availability of non-invasive assessments of myocardial deformation in clinical research and practice. Its widespread availability thanks to the fact that this technology can in principle be applied on images that are part of every CMR or echocardiographic protocol. However, the two modalities are based on very different methods of image acquisition and reconstruction, each with their respective strengths and limitations. The image tracking methods applied are not necessarily directly comparable between the modalities, or with those based on dedicated CMR acquisitions for strain measurement such as tagging or displacement encoding. Here we describe the principles underlying the image tracking methods for CMR and echocardiography, and the translation of the resulting tracking estimates into parameters suited to describe myocardial mechanics. Technical limitations are presented with the objective of suggesting potential solutions that may allow informed and appropriate use in clinical applications.

Advances in Echocardiographic Imaging in Heart Failure With Reduced and Preserved Ejection Fraction

Echocardiography, given its safety, easy availability, and the ability to permit a comprehensive assessment of cardiac structure and function, is an indispensable tool in the evaluation and management of patients with heart failure (HF). From initial phenotyping and risk stratification to providing vital data for guiding therapeutic decision-making and monitoring, echocardiography plays a pivotal role in the care of HF patients. The recent advent of multiparametric approaches for myocardial deformation imaging has provided valuable insights in the pathogenesis of HF, elucidating distinct patterns of myocardial dysfunction and events that are associated with progression from subclinical stage to overt HF. At the same time, miniaturization of echocardiography has further expanded clinical application of echocardiography, with the use of pocket cardiac ultrasound as an adjunct to physical examination demonstrated to improve diagnostic accuracy and risk stratification. Furthermore, ongoing advances in the field of big data analytics promise to create an exciting opportunity to operationalize precision medicine as the new approach to healthcare delivery that aims to individualize patient care by integrating data extracted from clinical, laboratory, echocardiographic, and genetic assessments. The present review summarizes the recent advances in the field of echocardiography, with emphasis on their role in HF phenotyping, risk stratification, and optimizing clinical outcomes.