Feasibility of left atrial strain assessment using cardiac computed tomography in patients with paroxysmal atrial fibrillation

PURPOSE

To evaluate the feasibility of left atrial strain (LAS) assessment using cardiac computed tomography (CT) in patients with paroxysmal atrial fibrillation (PAF).

METHODS

This retrospective single-center study included 98 patients with PAF who underwent cardiac CT and echocardiography before the first catheter ablation. LAS was analyzed using cardiac CT (CT-LAS) and speckle-tracking echocardiography (STE; STE-LAS). LA reservoir (LASr), conduit (LASc), and pump strain (LASp) were calculated by averaging LAS measured in 4- and 2-chamber views. The results were compared using Pearson's correlation coefficients, paired t-tests, and Bland-Altman analysis. Intraclass correlation coefficients (ICCs) were used to evaluate reproducibility.

RESULTS

CT-LAS could be analyzed in all patients, while STE-LAS could be analyzed in 53 (54%) patients. LASr, LASc, and LASp showed significant correlations between CT- and STE-LAS: LASr, r = 0.68, p < 0.001; LASc, r = 0.47, p < 0.001; LASp, r = 0.67, p < 0.001. LASr, LASc, and LASp of CT- and STE-LAS were 23.7 ± 6.0% and 22.1 ± 6.7%, 11.1 ± 3.6% and 11.1 ± 4.1%, and 12.6 ± 4.6% and 11.0 ± 4.1%, respectively. LASr and LASp were significantly higher in CT-LAS than that in STE-LAS (p = 0.023 for LASr and p = 0.001 for LASp). CT-LAS showed excellent reproducibility. The intra- and interobserver ICCs were 0.96 to 0.99 and 0.89 to 0.90, respectively.

CONCLUSION

CT-LAS was successfully analyzed in more patients than STE-LAS and was highly reproducible. The findings suggest that CT-LAS is feasible for patients with PAF.

Time Course of Left Ventricular Strain Assessment via Cardiovascular Magnetic Resonance Myocardial Feature Tracking in Takotsubo Syndrome

Background: Although takotsubo syndrome (TTS) is characterized by transient systolic dysfunction of the left ventricle (LV), the time course and mechanism of LV function recovery remain elusive. The aim of this study is to evaluate cardiac functional recovery in TTS via serial cardiac magnetic resonance feature tracking (CMR-FT). Methods: In this Japanese multicenter registry, patients with newly diagnosed TTS were prospectively enrolled. In patients who underwent serial cardiovascular magnetic resonance (CMR) imaging at 1 month and 1 year after the onset, CMR-FT was performed to determine the global circumferential strain (GCS), global radial strain (GRS) and global longitudinal strain (GLS). We compared LV ejection fraction, GCS, GRS and GLS at 1 month and 1 year after the onset of TTS. Results: Eighteen patients underwent CMR imaging in one month and one year after the onset in the present study. LV ejection fraction had already normalized at 1 month after the onset, with no significant difference between 1 month and 1 year (55.8 ± 9.2% vs. 58.9 ± 7.3%, p = 0.09). CMR-FT demonstrated significant improvement in GCS from 1 month to 1 year (-16.7 ± 3.4% vs. -18.5 ± 3.2%, p < 0.01), while there was no significant difference in GRS and GLS between 1 month and year (GRS: 59.6 ± 24.2% vs. 59.4 ± 17.3%, p = 0.95, GLS: -12.8 ± 5.9% vs. -13.8 ± 4.9%, p = 0.42). Conclusions: Serial CMR-FT analysis revealed delayed improvement of GCS compared to GRS and GLS despite of rapid recovery of LV ejection fraction. CMR-FT can detect subtle impairment of LV systolic function during the recovery process in patients with TTS.

Left ventricular strain changes at high altitude in rats: a cardiac magnetic resonance tissue tracking imaging study

BACKGROUND

Long-term exposure to a high altitude environment with low pressure and low oxygen could cause abnormalities in the structure and function of the heart. Myocardial strain is a sensitive indicator for assessing myocardial dysfunction, monitoring myocardial strain is of great significance for the early diagnosis and treatment of high altitude heart-related diseases. This study applies cardiac magnetic resonance tissue tracking technology (CMR-TT) to evaluate the changes in left ventricular myocardial function and structure in rats in high altitude environment.

METHODS

6-week-old male rats were randomized into plateau hypoxia rats (plateau group, n = 21) as the experimental group and plain rats (plain group, n = 10) as the control group. plateau group rats were transported from Chengdu (altitude: 360 m), a city in a plateau located in southwestern China, to the Qinghai-Tibet Plateau (altitude: 3850 m), Yushu, China, and then fed for 12 weeks there, while plain group rats were fed in Chengdu(altitude: 360 m), China. Using 7.0 T cardiac magnetic resonance (CMR) to evaluate the left ventricular ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), as well as myocardial strain parameters including the peak global longitudinal (GLS), radial (GRS), and circumferential strain (GCS). The rats were euthanized and a myocardial biopsy was obtained after the magnetic resonance imaging scan.

RESULTS

The plateau rats showed more lower left ventricular GLS and GRS (P < 0.05) than the plain rats. However, there was no statistically significant difference in left ventricular EDV, ESV, SV, EF and GCS compared to the plain rats (P > 0.05).

CONCLUSIONS

After 12 weeks of exposure to high altitude low-pressure hypoxia environment, the left ventricular global strain was partially decreased and myocardium is damaged, while the whole heart ejection fraction was still preserved, the myocardial strain was more sensitive than the ejection fraction in monitoring cardiac function.

Assessment of myocardial strain patterns in patients with left bundle branch block using cardiac magnetic resonance

Recently, a classification with four types of septal longitudinal strain patterns was described using echocardiography, suggesting a pathophysiological continuum of left bundle branch block (LBBB)-induced left ventricle (LV) remodeling. The aim of this study was to assess the feasibility of classifying these strain patterns using cardiovascular magnetic resonance (CMR), and to evaluate their association with LV remodeling and myocardial scar. Single center registry included LBBB patients with septal flash (SF) referred to CMR to assess the cause of LV systolic dysfunction. Semi-automated feature-tracking cardiac resonance (FT-CMR) was used to quantify myocardial strain and detect the four strain patterns. A total of 115 patients were studied (age 66 ± 11 years, 57% men, 28% with ischemic heart disease). In longitudinal strain analysis, 23 patients (20%) were classified in stage LBBB-1, 37 (32.1%) in LBBB-2, 25 (21.7%) in LBBB-3, and 30 (26%) in LBBB-4. Patients at higher stages had more prominent septal flash, higher LV volumes, lower LV ejection fraction, and lower absolute strain values (p < 0.05 for all). Late gadolinium enhancement (LGE) was found in 55% of the patients (n = 63). No differences were found between the strain patterns regarding the presence, distribution or location of LGE. Among patients with LBBB, there was a good association between strain patterns assessed by FT-CMR analysis and the degree of LV remodeling and LV dysfunction. This association seems to be independent from the presence and distribution of LGE.

Association of global longitudinal strain by feature tracking cardiac magnetic resonance imaging with adverse outcomes among community-dwelling adults without cardiovascular disease: The Dallas Heart Study

AIM

Left ventricular (LV) global longitudinal strain (GLS) may detect subtle abnormalities in myocardial contractility among individuals with normal LV ejection fraction (LVEF). However, the prognostic implications of GLS among healthy, community-dwelling adults is not well-established.

METHODS AND RESULTS

Overall, 2234 community-dwelling adults (56% women, 47% Black) with LVEF ≥50% without a history of cardiovascular disease (CVD) from the Dallas Heart Study who underwent cardiac magnetic resonance (CMR) with GLS assessed by feature tracking CMR (FT-CMR) were included. The association of GLS with the risk of incident major adverse cardiovascular events (MACE; composite of incident myocardial infarction, incident heart failure [HF], hospitalization for atrial fibrillation, coronary revascularization, and all-cause death), and incident HF or death were assessed with adjusted Cox proportional hazards models. A total of 309 participants (13.8%) had MACE during a median follow-up duration of 17 years. Participants with the worst GLS (Q4) were more likely male and of the Black race with a history of tobacco use and diabetes with lower LVEF, higher LV end-diastolic volume, and higher LV mass index. Cumulative incidence of MACE was higher among participants with worse (Q4 vs. Q1) GLS (20.4% vs. 9.0%). In multivariable-adjusted Cox models that included clinical characteristics, cardiac biomarkers and baseline LVEF, worse GLS (Q4 vs. Q1) was associated with a significantly higher risk of MACE (hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.07-2.24, p = 0.02) and incident HF or death (HR 1.57, 95% CI 1.03-2.38, p = 0.04).

CONCLUSIONS

Impaired LV GLS assessed by FT-CMR among adults free of cardiovascular disease is associated with a higher risk of incident MACE and incident HF or death independent of cardiovascular risk factors, cardiac biomarkers and LVEF.

Ethnic differences in cardiac structure and function assessed by MRI in healthy South Asian and White European people: A UK Biobank Study

BACKGROUND

Echocardiographic studies indicate South Asian people have smaller ventricular volumes, lower mass and more concentric remodelling than White European people, but there are no data using cardiac MRI (CMR). We aimed to compare CMR quantified cardiac structure and function in White European and South Asian people.

METHODS

Healthy White European and South Asian participants in the UK Biobank Imaging CMR sub-study were identified by excluding those with a history of cardiovascular disease, hypertension, obesity or diabetes. Ethnic groups were matched by age and sex. Cardiac volumes, mass and feature tracking strain were compared.

RESULTS

121 matched pairs (77 male/44 female, mean age 58 ± 8 years) of South Asian and White European participants were included. South Asian males and females had smaller absolute but not indexed left ventricular (LV) volumes, and smaller absolute and indexed right ventricular volumes, with lower absolute and indexed LV mass and lower LV mass:volume than White European participants. Although there were no differences in ventricular or atrial ejection fractions, LV global longitudinal strain was higher in South Asian females than White European females but not males, and global circumferential strain was higher in both male and South Asian females than White European females. Peak early diastolic strain rates were higher in South Asian versus White European males, but not different between South Asian and White European females.

CONCLUSIONS

Contrary to echocardiographic studies, South Asian participants in the UK Biobank study had less concentric remodelling and higher global circumferential strain than White European subjects. These findings emphasise the importance of sex- and ethnic- specific normal ranges for cardiac volumes and function.

Identification of patients with nonischemic dilated cardiomyopathy at risk of malignant ventricular arrhythmias: insights from cardiac magnetic resonance feature tracking

BACKGROUND

Patients with nonischemic dilated cardiomyopathy (NIDCM) are prone to arrhythmias, and the cause of mortality in these patients is either end-organ dysfunction due to pump failure or malignant arrhythmia-related death. However, the identification of patients with NIDCM at risk of malignant ventricular arrhythmias (VAs) is challenging in clinical practice. The aim of this study was to evaluate whether cardiovascular magnetic resonance feature tracking (CMR-FT) could help in the identification of patients with NIDCM at risk of malignant VAs.

METHODS

A total of 263 NIDCM patients who underwent CMR, 24-hour Holter electrocardiography (ECG) and inpatient ECG were retrospectively evaluated. The patients with NIDCM were allocated to two subgroups: NIDCM with VAs and NIDCM without VAs. From CMR-FT, the global peak radial strain (GPRS), global longitudinal strain (GPLS), and global peak circumferential strain (GPCS) were calculated from the left ventricle (LV) model. We investigated the possible predictors of NIDCM combined with VAs by univariate and multivariate logistic regression analyses.

RESULTS

The percent LGE (15.51 ± 3.30 vs. 9.62 ± 2.18, P < 0.001) was higher in NIDCM patients with VAs than in NIDCM patients without VAs. Furthermore, the NIDCM patients complicated with VAs had significantly lower GPCS than the NIDCM patients without VAs (- 5.38 (- 7.50, - 4.22) vs.-9.22 (- 10.73, - 8.19), P < 0.01). Subgroup analysis based on LGE negativity showed that NIDCM patients complicated with VAs had significantly lower GPRS, GPCS, and GPLS than NIDCM patients without VAs (P < 0.05 for all). Multivariate analysis showed that both GPCS and %LGE were independent predictors of NIDCM combined with VAs.

CONCLUSIONS

CMR global strain can be used to identify NIDCM patients complicated with VAs early, specifically when LGE is not present. GPCS < - 13.19% and %LGE > 10.37% are independent predictors of NIDCM combined with VAs.

An Integrated Algorithm for Differentiating Hypertrophic Cardiomyopathy From Hypertensive Heart Disease

BACKGROUND

Differentiating hypertrophic cardiomyopathy (HCM) from hypertensive heart disease (HHD) is challenging.

PURPOSE

To identify differences between HCM and HHD on a patient basis using MRI.

STUDY TYPE

Retrospective.

POPULATION

A total of 219 subjects, 148 in phase I (baseline data and algorithm development: 75 HCM, 33 HHD, and 40 controls) and 71 in phase II (algorithm validation: 56 HCM and 15 HHD).

FIELD STRENGTH/SEQUENCE

Contrast-enhanced inversion-prepared gradient echo and cine-balanced steady-state free precession sequences at 3.0 T.

ASSESSMENT

MRI parameters assessed included left ventricular (LV) ejection fraction (LVEF), LV end systolic and end diastolic volumes (LVESV and LVEDV), mean maximum LV wall thickness (MLVWT), LV global longitudinal and circumferential strain (GRS, GLS, and GCS), and native T1. Parameters, which were significantly different between HCM and HHD in univariable analysis, were entered into a principal component analysis (PCA). The selected components were then introduced into a multivariable regression analysis to model an integrated algorithm (IntA) for screening the two disorders. IntA performance was assessed for patients with and without LGE in phase I (development) and phase II (validation).

STATISTICAL TESTS

Univariable regression, PCA, receiver operating curve (ROC) analysis. A P value <0.05 was considered statistically significant.

RESULTS

Derived IntA formulation included LVEF, LVESV, LVEDV, MLVWT, and GCS. In LGE-positive subjects in phase l, the cutoff point of IntA ≥81 indicated HCM (83% sensitivity and 91% specificity), with the area under the ROC curve (AUC) of 0.900. In LGE-negative subjects, a higher possibility of HCM was indicated by a cutoff point of IntA ≥84 (100% sensitivity and 82% specificity), with an AUC of 0.947. Validation of IntA in phase II resulted in an AUC of 0.846 in LGE-negative subjects and 0.857 in LGE-positive subjects.

DATA CONCLUSION

A per-patient-based IntA algorithm for differentiating HCM and HHD was generated from MRI data and incorporated FT, LGE and morphologic parameters.

EVIDENCE LEVEL

3.

TECHNICAL EFFICACY

Stage 2.

Phenotyping heart failure by cardiac magnetic resonance imaging of cardiac macro- and microscopic structure: state of the art review

Heart failure demographics have evolved in past decades with the development of improved diagnostics, therapies, and prevention. Cardiac magnetic resonance (CMR) has developed in a similar timeframe to become the gold-standard non-invasive imaging modality for characterizing diseases causing heart failure. CMR techniques to assess cardiac morphology and function have progressed since their first use in the 1980s. Increasingly efficient acquisition protocols generate high spatial and temporal resolution images in less time. This has enabled new methods of characterizing cardiac systolic and diastolic function such as strain analysis, exercise real-time cine imaging and four-dimensional flow. A key strength of CMR is its ability to non-invasively interrogate the myocardial tissue composition. Gadolinium contrast agents revolutionized non-invasive cardiac imaging with the late gadolinium enhancement technique. Further advances enabled quantitative parametric mapping to increase sensitivity at detecting diffuse pathology. Novel methods such as diffusion tensor imaging and artificial intelligence-enhanced image generation are on the horizon. Magnetic resonance spectroscopy (MRS) provides a window into the molecular environment of the myocardium. Phosphorus (31P) spectroscopy can inform the status of cardiac energetics in health and disease. Proton (1H) spectroscopy complements this by measuring creatine and intramyocardial lipids. Hyperpolarized carbon (13C) spectroscopy is a novel method that could further our understanding of dynamic cardiac metabolism. CMR of other organs such as the lungs may add further depth into phenotypes of heart failure. The vast capabilities of CMR should be deployed and interpreted in context of current heart failure challenges.

Aortic Valve Area and Strain Measurements by Cardiac MRI and Transthoracic Echocardiography in Severe Aortic Stenosis with Normal Left Ventricular Function

Background

Transthoracic echocardiography (TTE) is the recommended imaging technique for the evaluation of patients with aortic stenosis (AS). However, in cases with inconclusive findings, cardiac magnetic resonance (CMR) planimetry is used to grade AS severity. This study aimed to compare the results derived from TTE and CMR in patients with severe AS with normal left ventricular (LV) function.

Methods

In a prospective study, 20 patients with severe AS were recruited and data derived from TTE and CMR modalities were compared with the archived records of 28 age- and sex-matched healthy controls. The data included aortic valve area (AVA), MRI-derived biventricular global strains, and TTE-derived global longitudinal strain (GLS). SPSS software was used to analyze the data with independent samples t test, intraclass correlation coefficient (ICC), and Pearson correlation. P<0.05 was considered statistically significant.

Results

An excellent agreement was found in AVA values derived from CMR and TTE with an average ICC of 0.932 (95% CI=0.829-0.973). There was a significant difference in LV-GLS, LV global radial strain (GRS), right ventricular (RV) GRS, and RV global circumferential strain between the groups. A good correlation was found between CMR- and TTE-derived GLS with an average ICC of 0.721 (95% C=0.255-0.896). The mean aortic valve pressure gradient in TTE had a significant inverse linear correlation with LV-GRS in CMR (r=-0.537). All P values were <0.05.

Conclusion

There was a good agreement between AVA and strain values derived from cardiac MRI and TTE. The myocardial strain was impaired in patients with severe AS and normal LV function and correlated with disease severity.

Changes in Computed-Tomography-Derived Segmental Left Ventricular Longitudinal Strain After Transcatheter Aortic Valve Implantation

Patients with severe aortic stenosis (AS) may show left ventricular (LV) apical longitudinal strain sparing. Transcatheter aortic valve implantation (TAVI) improves LV systolic function in patients with severe AS. However, the changes in regional longitudinal strain after TAVI have not been extensively evaluated. This study aimed to characterize the effect of the pressure overload relief after TAVI on LV apical longitudinal strain sparing. A total of 156 patients (mean age 80 ± 7 years, 53% men) with severe AS who underwent computed tomography before and within 1 year after TAVI (mean time to follow-up 50 ± 30 days) were included. LV global and segmental longitudinal strain were assessed using feature tracking computed tomography. LV apical longitudinal strain sparing was evaluated as the ratio between the apical and midbasal longitudinal strain and was defined as an LV apical to midbasal longitudinal strain ratio >1. LV apical longitudinal strain remained stable after TAVI (from 19.5 ± 7.2% to 18.7 ± 7.7%, p = 0.20), whereas LV midbasal longitudinal strain showed a significant increase (from 12.9 ± 4.2% to 14.2 ± 4.0%, p ≤0.001). Before TAVI, 88% of the patients presented with LV apical strain ratio >1% and 19% presented with an LV apical strain ratio >2. After TAVI, these percentages significantly decreased to 77% and 5% (p = 0.009, p ≤0.001), respectively. In conclusion, LV apical sparing of strain is a relatively common finding in patients with severe AS who underwent TAVI and its prevalence decreases after the afterload relief after TAVI.

Diagnostic accuracy of left atrial function and strain for differentiating between acute and chronic myocardial infarction

BACKGROUND

The cardiac magnetic resonance tissue tracking (CMR-TT) technique was used to obtain left atrial strain and strain rate in patients with myocardial infarction (MI) and to evaluate the utility of this technique in the quantitative assessment of myocardial infarction for distinguishing acute from chronic myocardial infarction.

METHODS

We retrospectively analyzed 36 consecutive patients with acute myocardial infarction (AMI) and 29 patients with chronic myocardial infarction (CMI) who underwent CMR and 30 controls. Left atrial (LA) and ventricular functions were quantified by volumetric, and CMR-TT derived strain analysis from long and short left ventricular view cines. Receiver Operating Characteristics (ROC) analysis was used to determine the diagnostic accuracy of CMR-TT strain parameters for discriminating between acute and chronic myocardial infarction.

RESULTS

AMI and CMI participants had impaired LA reservoir function, conduit function and LA booster pump dysfunction compared to the controls. LA strain was more sensitive than LV global strain for the assessment of the MI stage. Peak late-negative SR yielded the best areas under the ROC curve (AUC) of 0.879, showing differentiation between acute and chronic myocardial infarction of all the LA strain parameters obtained. The highest significant differences between chronic myocardial infarction and normal myocardium were also found in the LV strain (p < 0.001) and LA functional parameters (p < 0.001), but there was no difference between AMI and normals.

CONCLUSIONS

CMR-TT-derived LA strain is a potential and robust tool in demonstrating impaired LA mechanics and quantifying LA dynamics, which have high sensitivity and specificity in the differential diagnosis of acute versus chronic myocardial infarction. Their use is thus worth popularizing in clinical application.

The Interfield Strength Agreement of Left Ventricular Strain Measurements at 1.5 T and 3 T Using Cardiac MRI Feature Tracking

BACKGROUND

Left ventricular (LV) strain measurements can be derived using cardiac MRI from routinely acquired balanced steady-state free precession (bSSFP) cine images.

PURPOSE

To compare the interfield strength agreement of global systolic strain, peak strain rates and artificial intelligence (AI) landmark-based global longitudinal shortening at 1.5 T and 3 T.

STUDY TYPE

Prospective.

SUBJECTS

A total of 22 healthy individuals (mean age 36 ± 12 years; 45% male) completed two cardiac MRI scans at 1.5 T and 3 T in a randomized order within 30 minutes. FIELD STRENGTH/SEQUENCE: bSSFP cine images at 1.5 T and 3 T.

ASSESSMENT

Two software packages, Tissue Tracking (cvi42, Circle Cardiovascular Imaging) and QStrain (Medis Suite, Medis Medical Imaging Systems), were used to derive LV global systolic strain in the longitudinal, circumferential and radial directions and peak (systolic, early diastolic, and late diastolic) strain rates. Global longitudinal shortening and mitral annular plane systolic excursion (MAPSE) were measured using an AI deep neural network model.

STATISTICAL TESTS

Comparisons between field strengths were performed using Wilcoxon signed-rank test (P value < 0.05 considered statistically significant). Agreement was determined using intraclass correlation coefficients (ICCs) and Bland-Altman plots.

RESULTS

Minimal bias was seen in all strain and strain rate measurements between field strengths. Using Tissue Tracking, strain and strain rate values derived from long-axis images showed poor to fair agreement (ICC range 0.39-0.71), whereas global longitudinal shortening and MAPSE showed good agreement (ICC = 0.81 and 0.80, respectively). Measures derived from short-axis images showed good to excellent agreement (ICC range 0.78-0.91). Similar results for the agreement of strain and strain rate measurements were observed with QStrain.

CONCLUSION

The interfield strength agreement of short-axis derived LV strain and strain rate measurements at 1.5 T and 3 T was better than those derived from long-axis images; however, the agreement of global longitudinal shortening and MAPSE was good.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Contribution of Ventricular Motion and Sampling Location to Discrepancies in Two-Dimensional Versus Three-Dimensional Fetal Ventricular Strain Measures

BACKGROUND

Echocardiographic quantification of fetal cardiac strain is important to evaluate function and the need for intervention, with both two-dimensional (2D) and three-dimensional (3D) strain measurements currently feasible. However, discrepancies between 2D and 3D measurements have been reported, the etiologies of which are unclear. This study sought to determine the etiologies of the differences between 2D and 3D strain measurements.

METHODS

A validated cardiac motion-tracking algorithm was used on 3D cine ultrasound images acquired in 26 healthy fetuses. Both 2D and 3D myocardial strain quantifications were performed on each image set for controlled comparisons. Finite element modeling of 2 left ventricle (LV) models with minor geometrical differences were performed with various helix angle configurations for validating image processing results.

RESULTS

Three-dimensional longitudinal strain (LS) was significantly lower than 2D LS for the LV free wall and septum but not for the right ventricular (RV) free wall, while 3D circumferential strain (CS) was significantly higher than 2D CS for the LV, RV, and septum. The LS discrepancy was due to 2D long-axis imaging not capturing the out-of-plane motions associated with LV twist, while the CS discrepancy was due to the systolic motion of the heart toward the apex that caused out-of-plane motions in 2D short-axis imaging. A timing mismatch between the occurrences of peak longitudinal and circumferential dimensions caused a deviation in zero-strain referencing between 2D and 3D strain measurements, contributing to further discrepancies between the 2.

CONCLUSIONS

Mechanisms for discrepancies between 2D and 3D strain measurements in fetal echocardiography were identified, and inaccuracies associated with 2D strains were highlighted. Understanding of this mechanism is useful and important for future standardization of fetal cardiac strain measurements, which we propose to be important in view of large discrepancies in measured values in the literature.

Myocardial Deformation in the Pediatric Age Group: Normal Values for Strain and Strain Rate Using 2D Magnetic Resonance Feature Tracking

BACKGROUND

Myocardial deformation can be assessed from routine cardiac magnetic resonance (MR) images using two-dimensional feature tracking (2D-FT). Although reference values are essential for implementation of strain imaging in clinical practice, data for the healthy pediatric age group are limited.

PURPOSE

To provide pediatric MR reference values for strain and strain rate for all four heart chambers.

STUDY TYPE

Retrospective.

SUBJECTS

One hundred and fifty-seven healthy children from two institutions (102 male, age 4.7-18 years).

FIELD STRENGTH/SEQUENCE

1.5 T; balanced steady-state free precession sequence.

ASSESSMENT

Left ventricular (LV) global and regional longitudinal, circumferential, and radial strain and strain rate as well as right ventricular (RV) and atrial global and regional longitudinal strain and strain rate were measured in two-, three-, and four-chamber views and the short axis stack. The relationships between strain parameters and age, height, weight, and gender were investigated. Age- and height-specific centile curves and tables were created for LV strain and strain rate. For all other global strain parameters, the mean was calculated as a reference.

STATISTICAL TESTS

Lambda-mu-sigma (LMS)-method of Cole and Green, univariable, and multivariable linear regression models. A P value <0.05 was considered to be statistically significant.

RESULTS

Age, height and weight had a significant influence on LV global strain values. These parameters also showed an influence on RV strain but only in boys (girls P = 0.12) and none of the variables had a significant influence on atrial strain (P = 0.19-0.49). Gender differences were only found for RV strain values.

DATA CONCLUSION

Pediatric potential reference values for myocardial deformation parameters of both ventricles and atria are provided. The values may serve as a reference in future studies and clinical practice.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 5.

The effect of paclitaxel plus carboplatin chemotherapy on subclinical cardiotoxicity in patients with non-small cell lung cancer: A speckle tracking echocardiography-based study

BACKGROUND

Although chemotherapy-induced cardiotoxicity is an emerging problem, limited information is available on the effects of chemotherapy on left ventricular (LV) mechanical functions in patients with non-small cell lung cancer (NSCLC).

OBJECTIVE

We aimed to explore chemotherapy-induced alterations in cardiac mechanical functions in patients with NSCLC using speckle tracking echocardiography (STE).

METHODS

Seventy-one patients with NSCLC and 34 age and sex matched control subjects were consecutively included. Based on their good performance status (Eastern Cooperative Oncology Group performance status), 39 patients were treated with paclitaxel plus carboplatin (PC) regimen and 32 patients were treated with vinorelbine plus cisplatin (VC) regimen. All patients and controls underwent conventional two-dimensional echocardiography and STE at baseline to assess their LV functions. The echocardiographic examinations of NSCLC patients were repeated after the chemotherapy regimens.

RESULTS

None of the NSCLC patients developed any signs or symptoms of clinical heart failure during or after the chemotherapy. There were not any significant differences in LV ejection fraction between NSCLC patients and controls before and after chemotherapy. There were not any significant differences in baseline LV global longitudinal strain (GLS), radial strain (RS), and circumferential strain (CS) between NSCLC patients and controls. However, all LV GLS, RS and CS significantly decreased in patients treated with the PC regimen resulting in a significant difference compared to both VC group and controls while no significant decreases were observed in strain measures in VC group.

CONCLUSION

Paclitaxel plus carboplatin, but not VC, may induce subclinical cardiotoxicity in patients with NSCLC, which may be detected by STE.

A head-to-head comparison of fast-SENC and feature tracking to LV long axis strain for assessment of myocardial deformation in chest pain patients

BACKGROUND

Myocardial strain imaging has gained importance in cardiac magnetic resonance (CMR) imaging in recent years as an even more sensitive marker of early left ventricular dysfunction than left-ventricular ejection fraction (LVEF). fSENC (fast strain encoded imaging) and FT (feature tracking) both allow for reproducible assessment of myocardial strain. However, left-ventricular long axis strain (LVLAS) might enable an equally sensitive measurement of myocardial deformation as global longitudinal or circumferential strain in a more rapid and simple fashion.

METHODS

In this study we compared the diagnostic performance of fSENC, FT and LVLAS for identification of cardiac pathology (ACS, cardiac-non-ACS) in patients presenting with chest pain (initial hscTnT 5-52 ng/l). Patients were prospectively recruited from the chest pain unit in Heidelberg. The CMR scan was performed within 1 h after patient presentation. Analysis of LVLAS was compared to the GLS and GCS as measured by fSENC and FT.

RESULTS

In total 40 patients were recruited (ACS n = 6, cardiac-non-ACS n = 6, non-cardiac n = 28). LVLAS was comparable to fSENC for differentiation between healthy myocardium and myocardial dysfunction (GLS-fSENC AUC: 0.882; GCS-fSENC AUC: 0.899; LVLAS AUC: 0.771; GLS-FT AUC: 0.740; GCS-FT: 0.688), while FT-derived strain did not allow for differentiation between ACS and non-cardiac patients. There was significant variability between the three techniques. Intra- and inter-observer variability (OV) was excellent for fSENC and FT, while for LVLAS the agreement was lower and levels of variability higher (intra-OV: Pearson > 0.7, ICC > 0.8; inter-OV: Pearson > 0.65, ICC > 0.8; CoV > 25%).

CONCLUSIONS

While reproducibility was excellent for both FT and fSENC, it was only fSENC and the LVLAS which allowed for significant identification of myocardial dysfunction, even before LVEF, and therefore might be used as rapid supporting parameters for assessment of left-ventricular function.

A head-to-head comparison of myocardial strain by fast-strain encoding and feature tracking imaging in acute myocardial infarction

Background

Myocardial infarction (MI) is a major cause of heart failure. Left ventricular adverse remodeling is common post-MI. Several studies have demonstrated a correlation between reduced myocardial strain and the development of adverse remodeling. Cardiac magnetic resonance (CMR) with fast-strain encoding (fast-SENC) or feature tracking (FT) enables rapid assessment of myocardial deformation. The aim of this study was to establish a head-to-head comparison of fast-SENC and FT in post-ST-elevated myocardial infarction (STEMI) patients, with clinical 2D speckle tracking echocardiography (2DEcho) as a reference.

Methods

Thirty patients treated with primary percutaneous coronary intervention for STEMI were investigated. All participants underwent CMR examination with late gadolinium enhancement, cine-loop steady-state free precession, and fast-SENC imaging using a 1.5T scanner as well as a 2DEcho. Global longitudinal strain (GLS), segmental longitudinal strain (SLS), global circumferential strain (GCS), and segmental circumferential strain (SCS) were assessed along with the MI scar extent.

Results

The GCS measurements from fast-SENC and FT were nearly identical: the mean difference was 0.01 (2.5)% (95% CI - 0.92 to 0.95). For GLS, fast-SENC values were higher than FT, with a mean difference of 1.8 (1.4)% (95% CI 1.31-2.35). Tests of significance for GLS did not show any differences between the MR methods and 2DEcho. Average strain in the infarct-related artery (IRA) segments compared to the remote myocardium was significantly lower for the left anterior descending artery and right coronary artery culprits but not for the left circumflex artery culprits. Fast-SENC displayed a higher area under the curve for detecting infarcted segments than FT for both SCS and SLS.

Conclusion

GLS and GCS did not significantly differ between fast-SENC and FT. Both showed acceptable agreement with 2DEcho for longitudinal strain. Segments perfused by the IRA showed significantly reduced strain values compared to the remote myocardium. Fast-SENC presented a higher sensitivity and specificity for detecting infarcted segments than FT.

Diagnostic performance of cardiac magnetic resonance segmental myocardial strain for detecting microvascular obstruction and late gadolinium enhancement in patients presenting after a ST-elevation myocardial infarction

Background

Microvascular obstruction (MVO) and Late Gadolinium Enhancement (LGE) assessed in cardiac magnetic resonance (CMR) are associated with adverse outcome in patients with ST-elevation myocardial infarction (STEMI). Our aim was to analyze the diagnostic performance of segmental strain for the detection of MVO and LGE.

Methods

Patients with anterior STEMI, who underwent additional CMR were enrolled in this sub-study of the CARE-AMI trial. Using CMR feature tracking (FT) segmental circumferential peak strain (SCS) was measured and the diagnostic performance of SCS to discriminate MVO and LGE was assessed in a derivation and validation cohort.

Results

Forty-eight STEMI patients (62 ± 12 years old), 39 (81%) males, who underwent CMR (i.e., mean 3.0 ± 1.5 days) after primary percutaneous coronary intervention (PCI) were included. All patients presented with LGE and in 40 (83%) patients, MVO was additionally present. Segments in all patients were visually classified and 146 (19%) segments showed MVO (i.e., LGE+/MVO+), 308 (40%) segments showed LGE and no MVO (i.e., LGE+/MVO–), and 314 (41%) segments showed no LGE (i.e., LGE–). Diagnostic performance of SCS for detecting MVO segments (i.e., LGE+/MVO+ vs. LGE+/MVO–, and LGE–) showed an AUC = 0.764 and SCS cut-off value was –11.2%, resulting in a sensitivity of 78% and a specificity of 67% with a positive predictive value (PPV) of 30% and a negative predictive value (NPV) of 94% when tested in the validation group. For LGE segments (i.e., LGE+/MVO+ and LGE+/MVO– vs. LGE–) AUC = 0.848 and SCS with a cut-off value of –13.8% yielded to a sensitivity of 76%, specificity of 74%, PPV of 81%, and NPV of 70%.

Conclusion

Segmental strain in STEMI patients was associated with good diagnostic performance for detection of MVO+ segments and very good diagnostic performance of LGE+ segments. Segmental strain may be useful as a potential contrast-free surrogate marker to improve early risk stratification in patients after primary PCI.

Echocardiographic and Cardiac Magnetic Resonance Imaging-Derived Strains in Relation to Late Gadolinium Enhancement in Hypertrophic Cardiomyopathy

We compared speckle tracking echocardiography (STE) and feature tracking cardiovascular magnetic resonance (FT-CMR) in patients with hypertrophic cardiomyopathy (HC) with a varying extent of fibrosis as defined by late gadolinium enhancement to look at the level of agreement between methods and their ability to relate those to myocardial fibrosis. At 2 reference centers, 79 patients with HC and 16 volunteers (the control group) underwent STE and CMR with late gadolinium enhancement and FT-CMR. Patients were classified into 3 categories: no detectable, limited, and extensive fibrosis. Global longitudinal strain (GLS) and global radial strain (GRS) were derived using FT-CMR and STE. STE-derived GRS was decreased in all HC categories compared with the control group (p <0.001), whereas FT-CMR GRS was reduced only in patients with HC with fibrosis (p <0.05). Reduced STE-derived GLS was associated with extensive fibrosis (p <0.05) and a value less than -15.2% identified those with extensive fibrosis (sensitivity 79%, specificity 92%, area under the curve 0.863, 95% confidence interval [CI] 0.76 to 0.97, p <0.001). Inter-modality agreement was moderate for STE versus CMR-GLS (overall population intra-class correlation coefficient = 0.615, 95% CI 0.42 to 0.75, p <0.001; patients with HC 0.63, 0.42 to 0.76, p <0.001) and GRS (overall population intra-class correlation coefficient = 0.601, 95% CI 0.397 to 0.735, p <0.001). A low level of agreement for GRS was seen between methods in patients with HC. In conclusion, strain indexes measured using echocardiography and CMR are reduced in patients with HC compared with the control group and correlate well with the burden of myocardial fibrosis. Reduced STE-GLS can identify patients with extensive fibrosis, but whether there is an added value for risk stratification for sudden cardiac death remains to be determined.

Evaluation of left cardiac chamber function with cardiac magnetic resonance and association with outcome in patients with systemic sclerosis

OBJECTIVE

This study aimed to determine whether lower values of feature-tracking cardiovascular magnetic resonance (CMR)-derived left atrial reservoir strain (LARS) and impaired left ventricular (LV) global longitudinal strain (GLS) were associated with the presence of symptoms and long-term prognosis in patients with SSc.

METHODS

A total of 100 patients {54 [interquartile range (IQR) 46-64] years, 42% male} with SSc who underwent CMR imaging at two tertiary referral centres were included. All patients underwent analysis of LARS and LV GLS using feature-tracking on CMR and were followed-up for the occurrence of all-cause mortality.

RESULTS

The median LV GLS was -21.8% and the median LARS was 36%. On multivariable logistic regression, LARS [odds ratio (OR) 0.964 per %, 95% CI 0.929, 0.998, P = 0.049] was independently associated with New York Heart Association (NYHA) class II-IV heart failure symptoms. Over a median follow-up of 37 (21-62) months, a total of 24 (24%) patients died. Univariable Cox regression analysis demonstrated that LARS [hazard ratio (HR) 0.94 per 1%, 95% CI 0.91, 0.97, P < 0.0001) and LV GLS (HR 1.10 per %, 95% CI 1.03, 1.17, P = 0.005) were associated with all-cause mortality, while LV ejection fraction was not. Likelihood ratio tests demonstrated that LARS provided incremental value over prognostically important clinical and imaging parameters, including late gadolinium enhancement.

CONCLUSION

In patients with SSc, LARS was independently associated with the presence of NYHA class II-IV heart failure symptoms. Although both LARS and LV GLS were associated with all-cause mortality, only LARS provided incremental value over all evaluated variables known to be prognostically important in patients with SSc.

Serial Assessment of Right Ventricular Deformation in Patients With Hypoplastic Left Heart Syndrome: A Cardiovascular Magnetic Resonance Feature Tracking Study

Background As right ventricular dysfunction is a major cause of adverse outcome in patients with hypoplastic left heart syndrome, the aim was to assess right ventricular function and deformation after Fontan completion by performing 2-dimensional cardiovascular magnetic resonance feature tracking in serial cardiovascular magnetic resonance studies. Methods and Results Cardiovascular magnetic resonance examinations of 108 patients with hypoplastic left heart syndrome (female: 31) were analyzed. Short-axis cine images were used for right ventricular volumetry. Two-dimensional cardiovascular magnetic resonance feature tracking was performed using long-axis and short-axis cine images to measure myocardial global longitudinal, circumferential, and radial strain. All patients had at least 2 cardiovascular magnetic resonance examinations after Fontan completion and 41 patients had 3 examinations. Global strain values and right ventricular ejection fraction decreased from the first to the third examination with a significant decline in global longitudinal strain from the first examination to the second examination (median, first, and third quartile: -18.8%, [-20.5;-16.5] versus -16.9%, [-19.3;-14.7]) and from the first to the third examination in 41 patients (-18.6%, [-20.9;-15.7] versus -15.8%, [-18.7;-12.6]; P-values <0.004). Right ventricular ejection fraction decreased significantly from the first to the third examination (55.4%, [49.8;59.3] versus 50.2%, [45.0;55.9]; P<0.002) and from the second to the third examination (53.8%, [47.2;58.7] versus 50.2%, [45.0;55.9]; P<0.0002). Conclusions Serial assessment of cardiovascular magnetic resonance studies in patients with hypoplastic left heart syndrome after Fontan completion demonstrates a significant reduction in global strain values and right ventricular ejection fraction at follow-up. The significant reduction in global longitudinal strain between the first 2 examinations with non-significant changes in right ventricular ejection fraction suggest that global longitudinal strain measured by 2-dimensional cardiovascular magnetic resonance feature tracking might be a superior technique for the detection of changes in myocardial function.

The Agreement of a Two- and a Three-Dimensional Speckle-Tracking Global Longitudinal Strain

Background: Two-dimensional (2D) and three-dimensional (3D) speckle-tracking echocardiography (STE) enables assessment of myocardial function. Here, we examined the agreement between 2D and 3D STE measurement of a global longitudinal strain (GLS) in patients with normal left ventricle, reduced ejection fraction, and cardiac pacing. Methods: Our analysis included 90 consecutive patients (59% males; average age: 73.2 ± 11.2 years) examined between May 2019−December 2020, with valid 2D and 3D loops for further speckle-tracking strain analysis. Linear regression, Pearson correlation, and a Bland−Altman plot were used to quantify the association between 2D and 3D GLS and related segments, using the 17-segment American Heart Association (AHA) model. Analyses were performed in the entire study group and subgroups. Intra- and inter-observer variability of 2D and 3D GLS measurement was also performed in all participants. Results: We observed a strong correlation between 2D and 3D GLS measurements (R = 0.76, p < 0.001), which was higher in males (R = 0.78, p < 0.001) than females (R = 0.69, p < 0.001). Associated segment correlation was poor (R = 0.2−0.5, p < 0.01). The correlation between 2D and 3D GLS was weaker in individuals with ventricular pacing of >50% (R = 0.62, p < 0.001) than <50% (R = 0.8, p < 0.001), and in patients with LVEF of <35% (R = 0.69, p = 0.002) than >35% (R = 0.72, p < 0.001). Intra-observer variability for 2D and 3D GLS was 2 and 2.3%, respectively. Inter-observer variability for 2D and 3D GLS was 3.8 and 3.6%, respectively Conclusion: Overall 2D and 3D GLS were closely associated but not when analyzed per segment. It seems that GLS comparison is more representative of global shortening than local displacement. Right ventricular pacing and reduced left ventricular ejection fraction were associated with a reduced correlation between 2D and 3D GLS.

Myocardial Mass Corrected CMR Feature Tracking-Based Strain Ratios are Different in Pathologies With Increased Myocardial Mass

RATIONALE AND OBJECTIVES

Acute myocarditis (AM) and hypertensive heart disease (HHD) have different pathophysiological backgrounds, thus potentially showing distinct patterns of altered myocardial deformation. Therefore, CMR left ventricular (LV) feature tracking (FT)- based strain parameters were indexed to myocardial mass index (LVMi) in order to evaluate potential additional value in the differentiation among AM, HHD, and healthy volunteers (HV) compared to non-indexed conventional strain.

MATERIALS AND METHODS

Patients with AM (n = 43) and HHD (n = 28) underwent CMR at 3T. 61 HV served as controls. Cine imaging-based FT-strain analysis was performed and natural strain (nStrain) values were evaluated for gender and age specific differences in HV. Strain parameters were indexed to LVMi yielding ratio Strain (rStrain). These were evaluated for their discriminatory accuracy compared to nStrain values.

RESULTS

There were significant differences in nStrain between genders (p < 0.05), but not between age groups in HV. Circumferential strains differentiated best between HV and AM, reaching an area under the curve (AUC) of 0.86 (female) and 0.81 (male), yielding 93 (72) % sensitivity and 55 (75) % specificity. In discriminating between HV and HHD as well as AM and HHD, longitudinal strains outperformed all other parameters with AUCs of 1.00 (female)/ 0.92 (male) and 0.90 (female)/ 0.74 (male), respectively. Sensitivity and specificity levels of 100 %/ 100 % (female) and 91 %/ 72 % (male) for HV versus AM as well as 82 %/ 71 % (female) and 91%/ 57 % (male) for AM versus HHD could be demonstrated. The usage of rStrains significantly increased the AUC for circumferential and radial strains in male patients.

CONCLUSION

rStrain provided additional value in the differentiation of diseases with increased LVM. As rStrain is derived from standard native cine imaging, such parameters can be time efficiently and reliably calculated, giving them the potential to be a powerful addition to the currently developing multiparametric native diagnostic approaches.

State-of-the-art myocardial strain by CMR feature tracking: clinical applications and future perspectives

Based on conventional cine sequences of cardiac magnetic resonance (CMR), feature tracking (FT) is an emerging tissue tracking technique that evaluates myocardial motion and deformation quantitatively by strain, strain rate, torsion, and dyssynchrony. It has been widely accepted in modern literature that strain analysis can offer incremental information in addition to classic global and segmental functional analysis. Furthermore, CMR-FT facilitates measurement of all cardiac chambers, including the relatively thin-walled atria and the right ventricle, which has been a difficult measurement to obtain with the reference standard technique of myocardial tagging. CMR-FT objectively quantifies cardiovascular impairment and characterizes myocardial function in a novel way through direct assessment of myocardial fiber deformation. The purpose of this review is to discuss the current status of clinical applications of myocardial strain by CMR-FT in a variety of cardiovascular diseases. KEY POINTS: • CMR-FT is of great value for differential diagnosis and provides incremental value for evaluating the progression and severity of diseases. • CMR-FT guides the early diagnosis of various cardiovascular diseases and provides the possibility for the early detection of myocardial impairment and additional information regarding subclinical cardiac abnormalities. • Direct assessment of myocardial fiber deformation using CMR-FT has the potential to provide prognostic information incremental to common clinical and CMR risk factors.

Prognostic value of strain by feature-tracking cardiac magnetic resonance in arrhythmogenic right ventricular cardiomyopathy

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by ventricular dysfunction and ventricular arrhythmias (VA). Adequate arrhythmic risk assessment is important to prevent sudden cardiac death. We aimed to study the incremental value of strain by feature-tracking cardiac magnetic resonance imaging (FT-CMR) in predicting sustained VA in ARVC patients.

METHODS AND RESULTS

CMR images of 132 ARVC patients (43% male, 40.6 ± 16.0 years) without prior VA were analysed for global and regional right and left ventricular (RV, LV) strain. Primary outcome was sustained VA during follow-up. We performed multivariable regression assessing strain, in combination with (i) RV ejection fraction (EF); (ii) LVEF; and (iii) the ARVC risk calculator. False discovery rate adjusted P-values were given to correct for multiple comparisons and c-statistics were calculated for each model. During 4.3 (2.0-7.9) years of follow-up, 19% of patients experienced sustained VA. Compared to patients without VA, those with VA had significantly reduced RV longitudinal (P ≤ 0.03) and LV circumferential (P ≤ 0.04) strain. In addition, patients with VA had significantly reduced biventricular EF (P ≤ 0.02). After correcting for RVEF, LVEF, and the ARVC risk calculator separately in multivariable analysis, both RV and LV strain lost their significance [hazard ratio 1.03-1.18, P > 0.05]. Likewise, while strain improved the c-statistic in combination with RVEF, LVEF, and the ARVC risk calculator separately, this did not reach statistical significance (P ≥ 0.18).

CONCLUSION

Both RV longitudinal and LV circumferential strain are reduced in ARVC patients with sustained VA during follow-up. However, strain does not have incremental value over RVEF, LVEF, and the ARVC VA risk calculator.

Comprehensive evaluation of left ventricular deformation using speckle tracking echocardiography in normal children: comparison of three-dimensional and two-dimensional approaches

Background

Three-dimensional (3D) speckle tracking echocardiography (STE) can overcome some of the inherent limitations of two-dimensional (2D) STE; however, clinical experience is lacking. We aimed to assess and compare the feasibility, agreement, and reproducibility of left ventricular (LV) global longitudinal (GLS), and regional strain by 3D vs 2D STE in normal children.

Methods

Healthy pediatric subjects (n = 105, age mean = 11.2 ± 5.5 years) were prospectively enrolled. Three-dimensional and 2D LV GLS, as well as regional strain in 16 myocardial segments were quantified. Bland Altman analysis, intra- class correlation coefficients (ICC), percent error and linear regression were used for agreement and correlation between the two techniques. Analysis and acquisition times were compared. Inter- and intra-observer reproducibility was assessed in 20 studies.

Results

There was good to excellent agreement for 2D and 3D global longitudinal strain (ICC =0.82) and modest agreement for regional strain (ICC range 0.43–0.71). Both methods had high feasibility (88.6% for 2D vs 85.7% for 3D, p = 0.21), although 3D STE required significantly shorter acquisition and analysis time than 2D STE (acquisition time 1 ± 1.2 mins vs 2.4 ± 1 mins; p = 0.03, analysis time = 3.3 ± 1 mins vs 8.2 ± 2.5 mins; p = 0.001, respectively). Inter and intra-observer reproducibility was excellent for GLS by the two techniques (ICC = 0.78–0.93) but moderate to poor for regional strain (ICC = 0.21–0.64).

Conclusion

Three-dimensional global LV strain is as feasible and reproducible as 2D strain, with good agreement yet significantly more efficient acquisition and analysis. Regional strain is less concordant and 2D and 3D values should not be used interchangeably. 3D LV GLS may represent a viable alternative in evaluation of LV deformation in pediatric subjects.

1. Adequate feasibility of 3D STE in pediatrics; comparable to 2D STE.

2. Significantly shorter acquisition and analysis time for 3D GLS compared to 2D GLS.

3. Excellent agreement between 3D and 2D LV GLS and moderate to poor agreement between regional strain values.

4. Excellent inter and intra-observer reproducibility for GLS by the two techniques, and fair to poor reproducibility for regional strain (higher for apical than basal regions).

2D-echocardiography vs cardiac MRI strain: a prospective cohort study in patients with HER2-positive breast cancer undergoing trastuzumab

BACKGROUND

We aimed to study the predictive value of early two-dimensional echocardiography (2DE) speckle tracking (ST) for left ventricular ejection fraction (LVEF) changes during trastuzumab treatment for HER2-positive breast cancer.

METHODS

HER2-positive breast cancer patients receiving trastuzumab, with or without anthracycline, underwent 2DE-ST at baseline and after 3 and 6 months (m) trastuzumab. Cardiac magnetic resonance (CMR) imaging (with ST) was performed at baseline and 6 m. We studied the correlation between 2DE-ST- and CMR-derived global longitudinal strain (GLS) and global radial strain (GRS) measured at the same time. Additionally, we associated baseline and 3 m 2DE-ST measurements with later CMR-LVEF, and with cardiotoxicity, defined as CMR-LVEF < 45% and/or absolute decline > 10% during trastuzumab.

RESULTS

Forty-seven patients were included. Median baseline LVEF was 60.4%. GLS measurements based on 2DE-ST and CMR showed weak correlation (Pearson's r = 0.33; p = 0.041); GRS measurements were uncorrelated (r = 0.09; p = 0.979). 2DE-LVEF at baseline and 3 m, and 2DE-ST-GLS at 3 m were predictive of CMR-LVEF at 6 m. In contrast, the change in 2DE-ST-GLS at 3 m was predictive of the change in CMR-LVEF at 6 m, whereas the change in 2DE-LVEF was not. Importantly, the 11 patients who developed cardiotoxicity (28%) had larger 2DE-ST-GLS change at 3 m than those who did not (median 5.2%-points versus 1.7%-points; odds ratio for 1% difference change 1.81, 95% confidence interval 1.11-2.93; p = 0.016; explained variance 0.34).

CONCLUSIONS

Correlations between 2DE-ST and CMR-derived measurements are weak. Nevertheless, ST-measurements appeared useful to improve the performance of 2DE in predicting LVEF changes after 6 m of trastuzumab treatment.

Asymptomatic myocardial dysfunction was revealed by feature tracking cardiac magnetic resonance imaging in patients with primary Sjögren's syndrome

AIM

To evaluate subclinical left ventricular (LV) regional dysfunction in patients with primary Sjögren's syndrome (pSS) using feature tracking cardiac magnetic resonance (FT-CMR) imaging and to identify pSS characteristics independently associated with LV regional dysfunction.

METHOD

Fifty patients with pSS and 20 controls without cardiovascular disease underwent non-contrast CMR imaging. Labial gland biopsy was performed in 42 patients (84%). Disease activity was assessed using the European League Against Rheumatism Sjögren's syndrome disease activity index (ESSDAI). LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were measured using FT-CMR.

RESULTS

No significant differences in cardiovascular risk factors were found between the pSS group and controls. The pSS group had significantly lower GLS (P = .015) and GCS (P = .008) than the control group. Multiple linear regression analysis indicated that GCS was significantly associated with Raynaud's phenomenon (P = .015), focus score ≥2 (P = .032), and total ESSDAI score ≥8 (P = .029).

CONCLUSION

FT-CMR can reveal subclinical LV regional dysfunction in patients with pSS without cardiovascular disease. Furthermore, patients with pSS and Raynaud's phenomenon, a focus score ≥2, or an ESSDAI score ≥8 were considered to be at high risk for myocardial dysfunction.

Myocardial strain by cardiac magnetic resonance: A valuable predictor of outcome after infarct revascularization

PURPOSE

To evaluate the prognostic value of left ventricular strains by cardiac magnetic resonance feature tracking (CMR-FT) in patients with re-perfused myocardial infarction (MI).

METHODS

The study enrolled 58 patients with re-vascularized MI who underwent CMR within a week from acute MI. An 18-month follow-up was carried out for the composite endpoint of major adverse cardiovascular events (MACE). A 3 to 6-month post-MI ejection fraction (EF) was also measured. The predictive value of global longitudinal, circumferential, and radial strains (GLS, GCS, and GRS, respectively) for MACE and the follow-up EF was evaluated.

RESULTS

All the global strains showed significant impairment in MACE positive cases (P < 0.05 for all). On univariate regression, MACE was reversely associated with early post-MI EF (OR: 0.90, 95% CI: 0.83-0.98, P: 0.01), and directly associated with GLS (OR: 1.32, 95% CI: 1.03-1.69, P: 0.02), GCS (OR: 1.23, 95% CI: 1.00-1.50, P: 0.04) and EDVI (OR:1.02, 95 %CI: 1.00-1.04, P: 0.01). On multivariate regression model, only the interaction between EF and GLS showed a significant association with MACE (OR[CI95%]: 1.1 [1.06-1.21]). EF < 30% and GLS > -8.9% had the highest sensitivity (78.9% and 89.5%, respectively) and specificity (45.2% and 54.8%, respectively) to predict MACE. The combination of EF < 30% and GLS > -8.9% increased the sensitivity to 94.7%. In addition, the cutoff values of 35.1% for early post-MI EF and -10% for GLS could identify patients with impaired follow-up EF with more than 80% sensitivity and specificity [AUC (CI95%): 0.893(0.76-1.00) for EF and AUC (CI95%):0.836(0.67-1,00) for GLS, P < 0.05 for both)].

CONCLUSIONS

GLS by CMR-FT is a powerful prognosticator of MACE and functional recovery in MI survivors, with incremental value added to early post-MI EF alone.

A head-to-head comparison of speckle tracking echocardiography and feature tracking cardiovascular magnetic resonance imaging in right ventricular deformation

AIMS

Speckle tracking echocardiography (STE) and feature tracking cardiovascular magnetic resonance imaging (FT-CMR) are advanced imaging techniques which are both used for quantification of global and regional myocardial strain. Direct comparisons of STE and FT-CMR regarding right ventricular (RV) strain analysis are limited. We aimed to study clinical performance, correlation and agreement of RV strain by these techniques, using arrhythmogenic right ventricular cardiomyopathy (ARVC) as a model for RV disease.

METHODS AND RESULTS

We enrolled 110 subjects, including 34 patients with definite ARVC, 30 preclinical relatives of ARVC patients, and 46 healthy control subjects. Global and regional RV longitudinal peak strain (PS) were measured by STE and FT-CMR. Both modalities showed reduced strain values in ARVC patients compared to ARVC relatives (STE global PS: P < 0.001; FT-CMR global PS: P < 0.001) and reduced strain values in ARVC relatives compared to healthy control subjects (STE global PS: P = 0.042; FT-CMR global PS: P = 0.084). There was a moderate, albeit significant correlation between RV strain values obtained by STE and FT-CMR [global PS r = 0.578 (95% confidence interval 0.427-0.697), P < 0.001]. Agreement between the techniques was weak (limits of agreement for global PS: ±11.8%). Correlation and agreement both deteriorated when regional strain was studied.

CONCLUSION

RV STE and FT-CMR show a similar trend within the spectrum of ARVC and have significant correlation, but inter-modality agreement is weak. STE and FT-CMR may therefore both individually have added value for assessment of RV function, but RV PS values obtained by these techniques currently cannot be used interchangeably in clinical practice.

CMR-based T1-mapping offers superior diagnostic value compared to longitudinal strain-based assessment of relative apical sparing in cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative disease. In the present study, we compared the diagnostic accuracy of cardiovascular magnetic resonance (CMR)-based T1-mapping and subsequent extracellular volume fraction (ECV) measurement and longitudinal strain analysis in the same patients with (a) biopsy-proven cardiac amyloidosis (CA) and (b) hypertrophic cardiomyopathy (HCM). N = 30 patients with CA, N = 20 patients with HCM and N = 15 healthy control patients without relevant cardiac disease underwent dedicated CMR studies. The CMR protocol included standard sequences for cine-imaging, native and post-contrast T1-mapping and late-gadolinium-enhancement. ECV measurements were based on pre- and post-contrast T1-mapping images. Feature-tracking analysis was used to calculate 3D left ventricular longitudinal strain (LV-LS) in basal, mid and apical short-axis cine-images and to assess the presence of relative apical sparing. Receiver-operating-characteristic analysis revealed an area-under-the-curve regarding the differentiation of CA from HCM of 0.984 for native T1-mapping (p < 0.001), of 0.985 for ECV (p < 0.001) and only 0.740 for the "apical-to-(basal + midventricular)"-ratio of LV-LS (p = 0.012). A multivariable logistical regression analysis showed that ECV was the only statistically significant predictor of CA when compared to the parameter LV-LS or to the parameter "apical-to-(basal + midventricular)" LV-RLS-ratio. Native T1-mapping and ECV measurement are both superior to longitudinal strain measurement (with assessment of relative apical sparing) regarding the appropriate diagnosis of CA.

Aging and myocardial strain

Advanced age is widely recognized as a key risk factor for incident cardiovascular disease. The age-associated changes in cardiac properties alter the substrate on which cardiovascular disease is superimposed in various ways, and thus affect the development and manifestations of cardiovascular disease (CVD) in the elderly. However, it is still unclear whether age-related cardiac alteration is attributed to aging itself or whether it is secondary to other acquired cardiovascular risk factors. Understanding the association between aging and cardiac functional remodeling might provide insight into the pathogenesis of cardiovascular aging and may help inform possible preventive strategies for CVD in older individuals. Speckle-tracking echocardiography enables the objective and quantitative assessment of subtle myocardial alterations that are undetectable with conventional echocardiography, and has excellent feasibility and reproducibility. Left ventricular (LV) global longitudinal strain, a sensitive measure of LV systolic dysfunction, was found to be an independent risk factor for cardiovascular morbidity and mortality. More recently, deformation imaging has been employed to assess right ventricular (RV) and atrial performance, and impaired RV and atrial strain predict unfavorable outcomes in various clinical settings. This article reviews the association between aging and changes in myocardial strain values and describes future perspectives.

Postoperative evaluation of left ventricular global strain using cardiac computed tomography in pediatric patients with congenital heart disease: A comparison with echocardiography

PURPOSE

We explored the feasibility and reproducibility of cardiac computed tomography (CCT)-derived left ventricular (LV) global strain in postoperative children
with congenital heart disease (CHD) and compared its correlation and agreement with transthoracic echocardiography (TTE).

METHODS

Fifty-one patients (28 males, 23 females) were included who underwent clinically indicated retrospective electrocardiography-triggered CCT. and all patients underwent additional TTE on the same day. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were measured. Correlations of global strains between CCT and TTE were assessed using Pearson's correlation coefficient. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

RESULTS

GLS and GCS were not significantly different between CCT and TTE (GLS: -23.54 ± 3.24 vs. -23.85 ± 3.72, respectively, p = 0.415; GCS: -28.21 ± 3.55 vs. -28.79 ± 3.69, respectively, p = 0.155). GRS was significantly different between CCT and TTE (60.79 ± 15.11 vs. 41.73 ± 4.27, respectively, p < 0.001). There was good correlation between CCT- and TTE-derived GLS (r = 0.70, p < 0.001) and GCS (r = 0.68, p < 0.001), but GRS showed no correlation between CCT and TTE (r = 0.09, p = 0.54). CCT-derived global strain showed good intra- and inter-observer reproducibility (ICC = 0.86-0.92), except the inter-observer reproducibility for GRS (ICC = 0.77).

CONCLUSIONS

CCT was feasible for postoperative evaluation of LV global strain in pediatric patients with CHD with sufficient reproducibility. CCT-derived global strain can provide additional information in selected CHD patients with poor acoustic windows and who are intolerant to or have contraindications for cardiac magnetic resonance.

Correlation of Myocardial Strain and Late Gadolinium Enhancement by Cardiac Magnetic Resonance After a First Anterior ST-Segment Elevation Myocardial Infarction

Objectives: To investigate the correlation of cardiac magnetic resonance (CMR) feature-tracking with conventional CMR parameters in patients with a first anterior ST-segment elevation myocardial infarction (STEMI).

Methods: This sub-analysis of OCTAMI (Optical Coherence Tomography Examination in Acute Myocardial Infarction) registry included 129 patients who finished a CMR examination 1 month after a first anterior STEMI. Cine images were applied to calculate both global and segmental left ventricular peak strain parameters. The patients were divided into two groups by left ventricular ejection fraction (LVEF) and compared with 42 healthy controls. Segmental late gadolinium enhancement (LGE) was graded according to LGE transmurality as follows: (1) >0 to ≤ 25%; (2) >25 to ≤ 50%; (3) >50 to ≤ 75%; (4) >75%. Left ventricle was divided into infarcted, adjacent, and remote regions to assess regional function.

Results: Compared with controls, global radial (28.39 ± 5.08% vs. 38.54 ± 9.27%, p < 0.05), circumferential (−16.91 ± 2.11% vs. −20.77 ± 2.78%, p < 0.05), and longitudinal (−13.06 ± 2.15 vs. −15.52 ± 2.69, p < 0.05) strains were impaired in STEMI patients with normal LVEF (≥55%). Strain parameters were strongly associated with LGE (radial: r = 0.65; circumferential: r = 0.69; longitudinal: r = 0.61; all p < 0.05). A significant and stepwise impairment of global strains was observed in groups divided by LGE tertiles. Furthermore, segmental strain was different in various degrees of LGE transmurality especially for radial and circumferential strain. Strains of adjacent region were better than infarcted region in radial and circumferential directions and worse than remote region in all three directions.

Conclusion: Global and regional strain could stratify different extent and transmurality of LGE, respectively. Although without LGE, adjacent region had impaired strains comparing with remote region.

CMR-Based Risk Stratification of Sudden Cardiac Death and Use of Implantable Cardioverter-Defibrillator in Non-Ischemic Cardiomyopathy

Non-ischemic cardiomyopathy (NICM) is one of the most important entities for arrhythmias and sudden cardiac death (SCD). Previous studies suggest a lower benefit of implantable cardioverter–defibrillator (ICD) therapy in patients with NICM as compared to ischemic cardiomyopathy (ICM). Nevertheless, current guidelines do not differentiate between the two subgroups in recommending ICD implantation. Hence, risk stratification is required to determine the subgroup of patients with NICM who will likely benefit from ICD therapy. Various predictors have been proposed, among others genetic mutations, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume (LVEDD), and T-wave alternans (TWA). In addition to these parameters, cardiovascular magnetic resonance imaging (CMR) has the potential to further improve risk stratification. CMR allows the comprehensive analysis of cardiac function and myocardial tissue composition. A range of CMR parameters have been associated with SCD. Applicable examples include late gadolinium enhancement (LGE), T1 relaxation times, and myocardial strain. This review evaluates the epidemiological aspects of SCD in NICM, the role of CMR for risk stratification, and resulting indications for ICD implantation.

Multimodality imaging in valvular heart disease: how to use state-of-the-art technology in daily practice

Our understanding of the complexities of valvular heart disease (VHD) has evolved in recent years, primarily because of the increased use of multimodality imaging (MMI). Whilst echocardiography remains the primary imaging technique, the contemporary evaluation of patients with VHD requires comprehensive analysis of the mechanism of valvular dysfunction, accurate quantification of severity, and active exclusion extravalvular consequences. Furthermore, advances in surgical and percutaneous therapies have driven the need for meticulous multimodality imaging to aid in patient and procedural selection. Fundamental decision-making regarding whom, when, and how to treat patients with VHD has become more complex. There has been rapid technological advancement in MMI; many techniques are now available in routine clinical practice, and their integration into has the potential to truly individualize management strategies. This review provides an overview of the current evidence for the use of MMI in VHD, and how various techniques within each modality can be used practically to answer clinical conundrums.

Multiparametric Rest and Dobutamine Stress Magnetic Resonance in Assessment of Myocardial Viability

BACKGROUND

MR feature-tracking (FT) is a novel technique that quantitatively calculates myocardial strain and can assess myocardial viability.

PURPOSE

To evaluate the feasibility of FT at rest and with low-dose dobutamine (LDD), visual assessment of contractility with LDD and left ventricle (LV) end-diastolic wall thickness (EDWT) in the assessment of viability in ischemic cardiomyopathy (ICM) patients compared to delayed gadolinium enhancement (DGE).

STUDY TYPE

Prospective.

SUBJECTS

Thirty ICM patients and 30 healthy volunteers.

FIELD STRENGTH/SEQUENCES

A 1.5 T with balanced steady-state free precession (bSSFP) cine and phase-sensitive inversion prepared segmented gradient echo sequences.

ASSESSMENT

LDD (5 μg/kg/min and 10 μg/kg/min) was administered in the patient group. LV was divided into 16 segments and MR-FT was derived from bSSFP cine images using dedicated software. Viable segments were defined as those with a dobutamine-induced increase in resting MR-FT values >20%, a dobutamine-induced increase in systolic wall thickening ≥2 mm by visual assessment, ≤50% fibrosis on DGE, and resting EDWT ≥5.5 mm.

STATISTICAL TESTS

One-way analysis of variance (ANOVA), two-sampled t-test, paired samples t-test, and receiver operating characteristic (ROC) curve analysis. A P value < 0.05 was considered statistically significant.

RESULTS

Resting peak global circumferential (Ecc) and radial (Err) strains were significantly impaired in patients compared to controls (-11.7 ± 7.9 vs. -20.1 ± 5.7 and 19.7 ± 13.9 vs. 32.7 ± 15.4, respectively). Segments with no DGE (n = 354) and ≤ 50% (n = 38) DGE showed significant improvement of both Ecc and Err with LDD while segments with >50% DGE (n = 88) showed no improvement. In comparison to viable and nonviable segments identified by reference-standard DGE, the sensitivity, specificity, and diagnostic accuracy of the four methods were: 74%, 92%, and 89%, respectively, for Ecc; 70%, 89%, and 86%, respectively, for Err; 67%, 88%, and 84% for visual assessment; and 39%, 90%, and 80% for EDWT.

DATA CONCLUSION

Quantitative assessment of MR-FT, along with EDWT and qualitative visual assessment of myocardial contractility with LDD, are feasible alternative methods for the assessment of myocardial viability with moderate sensitivity and high specificity.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage: 2.

Evaluation of left ventricular myocardial mechanics in patients with normally functioning bicuspid aortic valves: A systematic review and meta-analysis

BACKGROUND

Studies have found conflicting results concerning the left ventricular (LV) myocardial deformation properties in patients with normally functioning bicuspid aortic valves (BAVs). Whether the remodeling process of LV occurs independently in patients with BAV is a matter of debate.

METHOD

We searched PubMed, Embase, Cochrane library, and Web of Science for cohort studies aiming to assess LV function in adults with isolated BAV compared with tricuspid aortic valve (TAV) controls. Standard mean difference (SMD) was calculated from random-effects meta-analyses.

RESULTS

Eight cohort studies were included. There were significantly lower global longitudinal strain (GLS), global radial strain (GRS), global circumferential strain (GCS) in BAV than in TAV controls (GLS: SMD = 0.64, 95% CI: 0.35 to 0.92, P < .0001; GRS: SMD = -0.71, 95% CI: -1.09 to -0.32, P = .0003; GCS: SMD = 0.70, 95% CI: 0.41 to 0.98, P < .00001) and significantly higher left atrial volume index (LAVI) and E/e' in BAV than in TAV controls (LAVI: SMD = 0.50, 95% Cl: 0.12 to 0.88, P = .01; E/e': SMD = 0.54, 95% CI: 0.30 to 0.77, P < .00001). There was significantly higher Left ventricular mass index（LVMI） in BAV than in TAV controls (SMD = 0.51, 95% CI: 0.24 to 0.79, P = .0003). Left ventricular ejection fraction (LVEF) was not significantly different between BAV patients and TAV controls (SMD = 0.05, 95% CI: -0.16 to 0.26, P = .63).

CONCLUSION

The impairment of LV myocardial mechanics, including LV systolic, diastolic dysfunction and LV hypertrophy, is present in patients with normally functioning BAV. This might support the hypothesis that BAV is not only a valvular disease but also a myocardial disease.

Everolimus for the Prevention of Calcineurin-Inhibitor-Induced Left Ventricular Hypertrophy After Heart Transplantation (RADTAC Study)

OBJECTIVES

This study aimed to determine the safety and efficacy of combined low-dose everolimus and low-dose tacrolimus compared with standard-dose tacrolimus in attenuating left ventricular hypertrophy (LVH) after orthotopic heart transplantation (OHT).

BACKGROUND

Calcineurin inhibitors (CNIs) such as tactrolimus are important in preventing cardiac allograft rejection and reducing mortality after OHT. However CNIs are causatively linked to the development of LVH, and are associated with nephrotoxicity and vasculopathy. CNI-sparing agents such as everolimus have been hypothesized to inhibit adverse effects of CNIs.

METHODS

In this prospective, randomized, open-label study, OHT recipients were randomized at 12 weeks after OHT to a combination of low-dose everolimus and tacrolimus (the RADTAC group) or standard-dose tacrolimus (the TAC group), with both groups coadministered mycophenolate and prednisolone. The primary endpoint was LVH indexed as the change in left ventricular mass (ΔLVM) by cardiovascular magnetic resonance (CMR) imaging from 12 to 52 weeks. Secondary endpoints included CMR-based myocardial performance, T1 fibrosis mapping, blood pressure, and renal function. Safety endpoints included episodes of allograft rejection and infection.

RESULTS

Forty stable OHT recipients were randomized. Recipients in the RADTAC group had significantly lower tacrolimus levels compared with the TAC group (6.5 ± 3.5 μg/l vs. 8.6 ± 2.8 μg/l; p = 0.02). The mean everolimus level in the RADTAC group was 4.2 ± 1.7 μg/l. A significant reduction in LVM was observed in the RADTAC group compared with an increase in LVM in the TAC group (ΔLVM = -13.0 ± 16.8 g vs. 2.1 ± 8.4 g; p < 0.001). Significant differences were also noted in secondary endpoints measuring function and fibrosis (Δ circumferential strain = -2.9 ± 2.8 vs. 2.1 ± 2.3; p < 0.001; ΔT1 mapping values = -32.7 ± 51.3 ms vs. 26.3 ± 90.4 ms; p = 0.003). No significant differences were observed in blood pressure (Δ mean arterial pressure = 4.2 ± 18.8 mm Hg vs. 2.8 ± 13.8 mm Hg; p = 0.77), renal function (Δ creatinine = 3.1 ± 19.9 μmol/l vs. 9 ± 21.8 μmol/l; p = 0.31), frequency of rejection episodes (p = 0.69), or frequency of infections (p = 0.67) between groups.

CONCLUSIONS

The combination of low-dose everolimus and tacrolimus compared with standard-dose tacrolimus safely attenuates LVH in the first year after cardiac transplantation with an observed reduction in CMR-measured fibrosis and an improvement in myocardial strain.

Assessment of myocardial deformation with CMR: a comparison with ultrasound speckle tracking

OBJECTIVES

Myocardial deformation integrated with cardiac dimensions provides a comprehensive assessment of cardiac function, which has proven useful to differentiate cardiac pathology from physiological adaptation to situations such as chronic intensive training. Feature tracking (FT) can measure myocardial deformation from cardiac magnetic resonance (CMR) cine sequences; however, its accuracy is not yet fully validated. Our aim was to compare the accuracy and reproducibility of FT with speckle tracking echocardiography (STE) in highly trained endurance athletes.

METHODS

Ninety-three endurance athletes (> 12-h training/week during the last 5 years, 52% male, 35 ± 5.1 years old) and 72 age-matched controls underwent resting CMR and transthoracic echocardiography to assess biventricular exercise-induced remodeling and biventricular global longitudinal strain (GLS) by CMR-FT and STE.

RESULTS

Strain values were significantly lower when assessed by CMR-FT compared to STE (p < 0.001), with good reproducibility for the left ventricle (bias = 3.94%, limit of agreement [LOA] = ± 4.27 %) but wider variability for right ventricle strain. Strain values by both techniques proportionally decreased with increasing ventricular volumes, potentially depicting the functional biventricular reserve that characterizes athletes' hearts.

CONCLUSIONS

Biventricular longitudinal strain values were lower when assessed by FT as compared to STE. Both methods were statistically comparable when measuring LV strain but not RV strain. These differences might be justified by the lower in-plane spatial and temporal resolution of FT, which is particularly relevant for the complex anatomy of the RV.

KEY POINTS

• Strain values were significantly lower when assessed by FT as compared to STE, which was expected due to the lower in-plane spatial and temporal resolution of FT versus STE. • Both methods were statistically comparable when measuring LV strain but not for RV strain analysis. • Characterizing the normal ranges and reproducibility of strain metrics by FT is an important step toward its clinical applicability, since it can be assessed offline and applied to routinely acquired cine CMR images.

Assessment of 10-Year Left-Ventricular-Remodeling by CMR in Patients Following Aortic Valve Replacement

Aims: Aortic valve replacement (AVR) may result in reverse cardiac remodeling. We aimed to assess long-term changes in the myocardium following AVR by Cardiac Magnetic Resonance Imaging (CMR).

Methods: We prospectively observed the long-term left ventricular (LV) function and structure of 27 patients with AVR [n = 19 with aortic stenosis (AS); n = 8 with aortic regurgitation (AR)] by CMR. Patients underwent CMR before, as well as 1, 5, and 10 years after AVR. We evaluated clinical parameters, LV volumes, mass, geometry, ejection fraction (EF), global myocardial longitudinal strain (MyoGLS), global myocardial circular strain (MyoGCS), hemodynamic forces (HemForces), and Late Gadolinium Enhancement (LGE).

Results: The median of LVMI, EDVI, and ESVI decreased in both groups. Patients with AR had higher initial values of EDVI and ESVI and showed a more prominent initial reduction. In AS, MyoGLS improved already after 1 year and remained constant afterward, whereas, in AR no improvement of MyoGLS was found. MyoGCS remained unchanged in the AS group but deteriorated in the AR group over 10 years. Ejection fraction (EF) was higher in AS patients compared to AR 10 years post-AVR. Late gadolinium enhancement (LGE) could be found more frequently in AS patients.

Conclusion: CMR was well suited to investigate myocardial changes over a 10-year follow up period in patients with aortic valve disease. Regarding the long-term functional changes following AVR, patients with AR seemed to benefit less from AVR compared to AS patients. Fibrosis was more common in AS, but this did not reflect functional evolution in these patients. Close monitoring seems indispensable to avoid irreversible structural damage of the heart and to perform AVR at an appropriate stage.

Direct comparison of multilayer left ventricular global longitudinal strain using CMR feature tracking and speckle tracking echocardiography

Background

Cardiac magnetic resonance feature tracking (CMR-FT) and speckle tracking echocardiography (STE) are well-established strain imaging modalities. Multilayer strain measurement permits independent assessment of endocardial and epicardial strain. This novel and layer specific approach to evaluating myocardial deformation parameters may provide greater insight into cardiac contractility when compared to whole-layer strain analysis. The aim of this study is to validate CMR-FT as a tool for multilayer strain analysis by providing a direct comparison between multilayer global longitudinal strain (GLS) values between CMR-FT and STE.

Methods

We studied 100 patients who had an acute myocardial infarction (AMI), who underwent CMR imaging and echocardiogram at baseline and follow-up (48 ± 13 days). Dedicated tissue tracking software was used to analyse single- and multi-layer GLS values for CMR-FT and STE.

Results

Correlation coefficients for CMR-FT and STE were 0.685, 0.687, and 0.660 for endocardial, epicardial, and whole-layer GLS respectively (all p < 0.001). Bland Altman analysis showed good inter-modality agreement with minimal bias. The absolute limits of agreement in our study were 6.4, 5.9, and 5.5 for endocardial, whole-layer, and epicardial GLS respectively. Absolute biases were 1.79, 0.80, and 0.98 respectively. Intraclass correlation coefficient (ICC) values showed moderate agreement with values of 0.626, 0.632, and 0.671 respectively (all p < 0.001).

Conclusion

There is good inter-modality agreement between CMR-FT and STE for whole-layer, endocardial, and epicardial GLS, and although values should not be used interchangeably our study demonstrates that CMR-FT is a viable imaging modality for multilayer strain

Quantification of Biventricular Myocardial Strain Using CMR Feature Tracking: Reproducibility in Small Animals

Myocardial strain is a well-validated parameter for evaluating myocardial contraction. Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a novel method for the quantitative measurements of myocardial strain from routine cine acquisitions. In this study, we investigated the influence of temporal resolution on tracking accuracy of CMR-FT and the intraobserver, interobserver, and interstudy reproducibilities for biventricular strain analysis in mice from self-gated CMR at 11.7 T. 12 constitutive nexilin knockout (Nexn-KO) mice, heterozygous (Het, N = 6) and wild-type (WT, N = 6), were measured with a well-established self-gating sequence twice within two weeks. CMR-FT measures of biventricular global and segmental strain parameters were derived. Interstudy, intraobserver, and interobserver reproducibilities were investigated. For the assessment of the impact of the temporal resolution for the outcome in CMR-FT, highly oversampled semi-4 chamber and midventricular short-axis data were acquired and reconstructed with 10 to 80 phases per cardiac cycle. A generally reduced biventricular myocardial strain was observed in Nexn-KO Het mice. Excellent intraobserver and interobserver reproducibility was achieved in all global strains (ICC range from 0.76 to 0.99), where global right ventricle circumferential strain (RCSSAX) showed an only good interobserver reproducibility (ICC 0.65, 0.11-0.89). For interstudy reproducibility, left ventricle longitudinal strain (LLSLAX) was the most reproducible measure of strain (ICC 0.90, 0.71-0.97). The left ventricle radial strain (LRSSAX) (ICC 0.50, 0.10-0.83) showed fair reproducibility and RCSSAX (ICC 0.36, 0.14-0.74) showed only poor reproducibility. In general, compared with global strains, the segmental strains showed relatively lower reproducibility. A minimal temporal resolution of 20 phases per cardiac cycle appeared sufficient for CMR-FT strain analysis. The analysis of myocardial strain from high-resolution self-gated cine images by CMR-FT provides a highly reproducible method for assessing myocardial contraction in small rodent animals. Especially, global LV longitudinal and circumferential strain revealed excellent reproducibility of intra- and interobserver and interstudy measurements.

Layer-Specific Strain Is Preload Dependent: Comparison between Speckle-Tracking Echocardiography and Cardiac Magnetic Resonance Feature-Tracking

BACKGROUND

Speckle-tracking echocardiographic (STE) imaging and cardiac magnetic resonance feature-tracking (CMR-FT) are novel imaging techniques enabling layer-specific quantification of myocardial deformation. Conventional echocardiographic parameters are load dependent, but few studies have investigated the effects of loading conditions on STE and CMR-FT layer-specific strain and the interchangeability of the two modalities. The aim of this study was to evaluate the effects of acute preload augmentation by saline infusion on STE and CMR-FT longitudinal and circumferential layer-specific strain parameters and their intermodal agreement.

METHODS

A total of 80 subjects, including 41 control subjects (mean age, 40 ± 12 years; 49% men) and 39 patients with cardiac disease (mean age, 47 ± 15 years; 92% men) were examined using STE and CMR-FT layer-specific strain analysis before and after saline infusion (median, 2.0 L) with quantification of transmural global longitudinal strain (GLS), epicardial GLS, endocardial GLS, transmural global circumferential strain (GCS), epicardial GCS, and endocardial GCS in addition to epicardial-endocardial gradients. Bland-Altman plots and Pearson correlation coefficients were used to evaluate agreement between the two modalities across all strain parameters.

RESULTS

Acute saline infusion increased all STE and CMR-FT layer-specific strain parameters in both groups. STE and CMR-FT GLS increased by 1.4 ± 1.5% and 1.5 ± 2.0% (P < .001) in control subjects and by 0.9 ± 1.8% and 0.9 ± 1.9% (P < .001) in patients with cardiac disease. STE and CMR-FT GCS increased by 2.0 ± 2.2% and 1.8 ± 2.3% (P < .001) in control subjects and by 1.8 ± 2.3% and 1.7 ± 3.6% in patients with cardiac disease (P < .001 and P = .03). STE longitudinal strain correlated strongly with corresponding CMR-FT longitudinal strain (GLS, epicardial GLS, and endocardial GLS: r = 0.81, r = 0.82, and r = 0.81, respectively) despite poor intermodal agreement (bias ± limits of agreement, -2.84 ± 4.06%, 0.16 ± 3.68%, and 2.33 ± 3.52%, respectively) whereas GCS, epicardial GCS, and endocardial GCS correlated weakly between the two modalities (r = 0.28, r = 0.19, and r = 0.34, respectively) and displayed poor intermodal agreement (bias ± limits of agreement, -1.33 ± 6.86%, 4.43 ± 6.49%, and -9.92 ± 8.55%, respectively).

CONCLUSIONS

STE and CMR-FT longitudinal and circumferential layer-specific strain parameters are preload dependent in both control subjects and patients with cardiac disease. STE and CMR-FT longitudinal layer-specific strain parameters are strongly correlated, whereas circumferential layer-specific strain parameters are weakly correlated. STE and CMR-FT longitudinal and circumferential strain should not be used interchangeably, because of poor intermodal agreement.

Comprehensive Assessment of Right Ventricular Function by Three-Dimensional Speckle-Tracking Echocardiography: Comparisons with Cardiac Magnetic Resonance Imaging

BACKGROUND

Three-dimensional speckle-tracking echocardiography (3D-STE) has been increasingly used to quantify right ventricular (RV) function. However, direct comparisons of 3D-STE with cardiac magnetic resonance (CMR) imaging for evaluation of RV function are limited. This study aimed to test the feasibility and accuracy of 3D-STE for the quantification of RV volumes, ejection fraction (EF), and longitudinal strain in comparison with CMR imaging and to determine whether 3D-STE for RV strain is superior to two-dimensional (2D) STE in comparison with CMR imaging.

METHODS

A total of 195 consecutive patients referred for both CMR imaging and echocardiography were studied. Right ventricular end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RVEF, and 3D RV longitudinal strain (3D-RVLS) of the free wall by 3D-STE and 2D-RVLS of the free wall by 2D-STE, were compared with CMR measurements. Pearson correlation and Bland-Altman analyses were used to assess the intertechnique agreement.

RESULTS

Right ventricular 3D-STE was feasible in 174 patients (89%). Right ventricular volumes and EF determined by 3D-STE strongly correlated with CMR values (RVEDV, r = 0.94; RVESV, r = 0.96; RVEF, r = 0.91; all P < .001). Three-dimensional STE slightly underestimated the RV volumes and longitudinal strain and overestimated the RVEF. The 3D-RVLS values correlated better than 2D-RVLS values with CMR values (0.85 vs 0.64, P < .001) with smaller bias and narrower limits of agreement (bias: 2.0 and 2.6; limits of agreement: 8.5 and 12.5, respectively). The bias and limits of agreement for 3D-STE-obtained RVLS were increased in patients with RV dilation, RVEF < 45%, or lower frame rate compared with those with normal RV size, RVEF ≥ 45%, or higher frame rate, respectively. Right ventricular 3D-STE measurements were highly reproducible.

CONCLUSIONS

The 3D-STE measurements of RV volumes, EF, and longitudinal strain are highly feasible and reproducible, and data measured by 3D-STE correlate strongly with those determined using CMR imaging. Thus, 3D-STE may be a valid alternative to CMR imaging for the quantification of RV function in everyday clinical practice.