Left ventricular global myocardial strain assessment comparing the reproducibility of four commercially available CMR-feature tracking algorithms

Potential prognostic impact of left-ventricular global longitudinal strain in analysis of whole-heart myocardial mechanics in nonischemic dilated cardiomyopathy

Cardiac magnetic resonance (CMR) feature-tracking (FT) has an important diagnostic role in non-ischemic dilated cardiomyopathy (NIDCM). To date, the relationship between whole-heart myocardial mechanics by CMR and early primary outcomes in NIDCM has not been elucidated. patients with NIDCM were eligible for this study. CMR-FT was used to analyze whole-heart myocardial mechanics. The primary outcomes were a composite of heart failure (HF) death, heart transplantation (HT), and hospitalization for HF worsening (WHF) after 1-year since diagnosis. 98 patients were included. During a 1-year follow-up, a worse prognosis occurred in 32 patients (30 hospitalizations for WHF, 8 deaths, and 3 HT). The left ventricular (LV) global longitudinal systolic strain (GLS), left ventricular global circumferential strain (LV GCS), strains of right ventricle and both atria were significantly reduced in patients with events vs. those without (GLS - 8.0 ± 3.4 vs. - 12.1 ± 4.5, p < 0.001; GCS - 13.0 ± 6.4 vs. - 18.3 ± 7.1, p < 0.001; right ventricular (RV) GLS - 12.1 ± 4.9 vs. - 17.4 ± 6.4, p < 0.001; left atrial longitudinal strain 7.5 ± 3.8 vs. 15.1 ± 12.3, p < 0.001; right atrial longitudinal strain 11.0 ± 6.7 vs. 17.2 ± 8.0, p < 0.001). Left ventricular ejection fraction (LVEF) was significantly higher in patients with better prognosis (22.7 ± 8.7 vs. 33.56 ± 10.4, p < 0.001). Multivariate regression analysis revealed LV GLS as an independent predictor of a worse prognosis (OR 0.787, CI 95% 0.697-0.890, p < 0.001). reduction of LV GLS showed the strongest predictive value for the composite outcome of WHF, HT, and HF death.

Normal Values for Atrial Deformation Measured by Feature-Tracking Cardiac MRI: A Meta-Analysis

BACKGROUND

A consensus on normal atrial deformation measurements by feature-tracking cardiac MRI remained absent.

PURPOSE

Provide reference ranges for atrial strain parameters in normal subjects, evaluating the influence of field strength and analysis software on the measurements.

STUDY TYPE

Meta-analysis.

POPULATION

2708 subjects from 42 studies undergoing cardiac MRI.

ASSESSMENT

A systematic search was conducted from database (PubMed, Web of Science, ScienceDirect, and EMBASE) inception through August 2023. The random-effects model was used to pool the means of biatrial strain parameters. Heterogeneity and clinical variable effects were assessed. Strain measurements among different field strengths and analysis software were compared.

STATISTICAL TESTS

The inverse-variance method, Cochrane Q statistic, and I2 value, meta-regression analysis, and ANOVA were used; P < 0.05 was considered statistically significant.

RESULTS

The pooled means of left atrial (LA) total strain (εs), passive strain (εe), and active strain (εa) were 37.46%, 22.73%, and 16.24%, respectively, and the pooled means of LA total strain rate (SRs), passive strain rate (SRe), and active strain rate (SRa) were 1.66, -1.95, and -1.83, indicating significant heterogeneity. The pooled means of right atrial (RA) εs, εe, and εa were 44.87%, 26.05%, and 18.83%. RA SRs, SRe, and SRa were 1.66, -1.95, and -1.83, respectively. The meta-regression identified age as significantly associated with LA εs, εe and SRe, field strength was associated with LA SRa (all P < 0.05). ANOVA revealed differences in LA εa and SRa among different analysis software and in LA εs and all LA strain rates (all P < 0.05) among field strengths. No significant differences were identified in RA strain across analysis software (RA strain: P = 0.145-0.749; RA strain rates: P = 0.073-0.744) and field strengths (RA strain: P = 0.641-0.794; RA strain rates: P = 0.204-0.458).

DATA CONCLUSION

This study demonstrated the pooled reference values of biatrial strain. Age, analysis software, and field strength were attributed to differences in LA strain, whereas RA strain showed consistency across different field strengths and analysis software. Limited study subjects may account for the absence of influence on RA strain.

LEVEL OF EVIDENCE: 1

TECHNICAL EFFICACY

Stage 5.

Reproducibility assessment of rapid strains in cardiac MRI: Insights and recommendations for clinical application

PURPOSE

Studies have shown the incremental value of strain imaging in various cardiac diseases. However, reproducibility and generalizability has remained an issue of concern. To overcome this, simplified algorithms such as rapid atrioventricular strains have been proposed. This multicenter study aimed to assess the reproducibility of rapid strains in a real-world setting and identify potential predictors for higher interobserver variation.

METHODS

A total of 4 sites retrospectively identified 80 patients and 80 healthy controls who had undergone cardiac magnetic resonance imaging (CMR) at their respective centers using locally available scanners with respective field strengths and imaging protocols. Strain and volumetric parameters were measured at each site and then independently re-evaluated by a blinded core lab. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to assess inter-observer agreement. In addition, backward multiple linear regression analysis was performed to identify predictors for higher inter-observer variation.

RESULTS

There was excellent agreement between sites in feature-tracking and rapid strain values (ICC ≥ 0.96). Bland-Altman plots showed no significant bias. Bi-atrial feature-tracking and rapid strains showed equally excellent agreement (ICC ≥ 0.96) but broader limits of agreement (≤18.0 % vs. ≤3.5 %). Regression analysis showed that higher field strength and lower temporal resolution (>30 ms) independently predicted reduced interobserver agreement for bi-atrial strain parameters (ß = 0.38, p = 0.02 for field strength and ß = 0.34, p = 0.02 for temporal resolution).

CONCLUSION

Simplified rapid left ventricular and bi-atrial strain parameters can be reliably applied in a real-world multicenter setting. Due to the results of the regression analysis, a minimum temporal resolution of 30 ms is recommended when assessing atrial deformation.

Association of uncertain significance genetic variants with myocardial mechanics and morphometrics in patients with nonischemic dilated cardiomyopathy

BACKGROUND

Careful interpretation of the relation between phenotype changes of the heart and gene variants detected in dilated cardiomyopathy (DCM) is important for patient care and monitoring.

OBJECTIVE

We sought to assess the association between cardiac-related genes and whole-heart myocardial mechanics or morphometrics in nonischemic dilated cardiomyopathy (NIDCM).

METHODS

It was a prospective study consisting of patients with NIDCM. All patients were referred for genetic testing and a genetic analysis was performed using Illumina NextSeq 550 and a commercial gene capture panel of 233 genes (Systems Genomics, Cardiac-GeneSGKit®). It was analyzed whether there are significant differences in clinical, two-dimensional (2D) echocardiographic, and magnetic resonance imaging (MRI) parameters between patients with the genes variants and those without. 2D echocardiography and MRI were used to analyze myocardial mechanics and morphometrics.

RESULTS

The study group consisted of 95 patients with NIDCM and the average age was 49.7 ± 10.5. All echocardiographic and MRI parameters of myocardial mechanics (left ventricular ejection fraction 28.4 ± 8.7 and 30.7 ± 11.2, respectively) were reduced and all values of cardiac chambers were increased (left ventricular end-diastolic diameter 64.5 ± 5.9 mm and 69.5 ± 10.7 mm, respectively) in this group. It was noticed that most cases of whole-heart myocardial mechanics and morphometrics differences between patients with and without gene variants were in the genes GATAD1, LOX, RASA1, KRAS, and KRIT1. These genes have not been previously linked to DCM. It has emerged that KRAS and KRIT1 genes were associated with worse whole-heart mechanics and enlargement of all heart chambers. GATAD1, LOX, and RASA1 genes variants showed an association with better cardiac function and morphometrics parameters. It might be that these variants alone do not influence disease development enough to be selective in human evolution.

CONCLUSIONS

Combined variants in previously unreported genes related to DCM might play a significant role in affecting clinical, morphometrics, or myocardial mechanics parameters.

Myocardial deformation characteristics assessed by cardiovascular magnetic resonance feature tracking in a healthy Chinese population

Purpose

To explore global/regional myocardial deformation across various layers, vascular distributions, specific levels and distinct walls in healthy individuals using cardiovascular magnetic resonance feature tracking (CMR-FT).

Methods

We selected a cohort of 55 healthy participants and CMR cine images were used to obtain the left ventricular (LV) peak longitudinal, circumferential, radial strains (LS, CS, RS). The characteristics of normal LV strain in various layers (endocardium, myocardium, epicardium), territories [left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA)], levels (basal, middle, apical) and walls (anterior, septum, inferior, lateral) were compared.

Results

The absolute values of the LV global LS and CS gradually decreased from endocardium to epicardium. The absolute LV global RS (65.7 ± 47.7%) was maximum relative to LS (-22.0 ± 10.8%) and CS (-22.8 ± 7.7%). The absolute values of the LCX territorial strain were the largest compared with the LAD and RCA territorial strains. Regional RS, endo-CS and endo-LS gradually increased from the basal to the apical level. The LV lateral walls had the highest strain values (CS, LS, and RS).

Conclusions

Variations in normal LV strain values across various layers, territories, levels, and walls were observed, suggesting the necessity for careful clinical interpretation of these strain values. These findings also partially revealed the complexity of normal cardiac mechanics.

The effect of hyperlipidemia and body fat distribution on subclinical left ventricular function in obesity: a cardiovascular magnetic resonance study

BACKGROUND

Obesity is often associated with multiple comorbidities. However, whether obese subjects with hyperlipidemia in the absence of other complications have worse cardiac indices than metabolically healthy obese subjects is unclear. Therefore, we aimed to determine the effect of hyperlipidemia on subclinical left ventricular (LV) function in obesity and to evaluate the association of cardiac parameters with body fat distribution.

MATERIALS AND METHODS

Ninety-two adults were recruited and divided into 3 groups: obesity with hyperlipidemia (n = 24, 14 males), obesity without hyperlipidemia (n = 25, 13 males), and c ntrols (n = 43, 25 males). LV strain parameters (peak strain (PS), peak diastolic strain rate (PDSR), peak systolic strain rate) derived from cardiovascular magnetic resonance tissue tracking were measured and compared. Dual-energy X-ray absorptiometer was used to measure body fat distribution. Correlations of hyperlipidemia and body fat distribution with LV strain were assessed by multivariable linear regression.

RESULTS

Obese individuals with preserved LV ejection fraction showed lower global LV longitudinal, circumferential, and radial PS and longitudinal and circumferential PDSR than controls (all P < 0.05). Among obese patients, those with hyperlipidemia had lower longitudinal PS and PDSR and circumferential PDSR than those without hyperlipidemia (- 12.8 ± 2.9% vs. - 14.2 ± 2.7%, 0.8 ± 0.1 s-1 vs. 0.9 ± 0.3 s-1, 1.2 ± 0.2 s-1 vs. 1.4 ± 0.2 s-1; all P < 0.05). Multivariable linear regression demonstrated that hyperlipidemia was independently associated with circumferential PDSR (β = - 0.477, P < 0.05) in obesity after controlling for growth differences, other cardiovascular risk factors, and central fat distribution. In addition, android fat had an independently negative relationship with longitudinal and radial PS (β = - 0.486 and β = - 0.408, respectively; all P < 0.05); and visceral fat was negatively associated with longitudinal PDSR (β = - 0.563, P < 0.05). Differently, gynoid fat was positively correlated with circumferential PS and PDSR and radial PDSR (β = 0.490, β = 0.481, and β = 0.413, respectively; all P < 0.05).

CONCLUSION

Hyperlipidemia is independently associated with subclinical LV diastolic dysfunction in obesity. Central fat distribution (android and visceral fat) has a negative association, while peripheral fat distribution (gynoid fat) has a positive association on subclinical LV function. These results suggest that appropriate management of hyperlipidemia may be beneficial for obese patients, and that the differentiation of fat distribution in different regions may facilitate the precise management of obese patients. Clinical trials registration Effect of lifestyle intervention on metabolism of obese patients based on smart phone software (ChiCTR1900026476).

Myocardial Strain Measurements Derived From MR Feature-Tracking: Influence of Sex, Age, Field Strength, and Vendor

BACKGROUND

Cardiac magnetic resonance feature tracking (CMR-FT) is a novel technique for assessing myocardial deformation and dysfunction. However, a comprehensive assessment of normal values of strain parameters in all 4 cardiac chambers using different vendors is lacking.

OBJECTIVES

This study aimed to characterize the normal values for myocardial strain in all 4 cardiac chambers and identify factors that contribute to variations in FT strain through a systematic review and meta-analysis of the CMR-FT published reports.

METHODS

The investigators searched PubMed, Embase, and Scopus for myocardial strains of all 4 chambers measured by CMR-FT in healthy adults. The pooled means of all strain parameters were generated using a random-effects model. Subgroup analyses and meta-regressions were performed to identify the sources of variations.

RESULTS

This meta-analysis included 44 studies with a total of 3,359 healthy subjects. The pooled means of left ventricular global longitudinal strain (LV-GLS), LV global radial strain, and LV global circumferential strain (GCS) were -18.4% (95% CI: -19.2% to -17.6%), 43.7% (95% CI: 40.0%-47.4%), and -21.4% (95% CI: -22.3% to -20.6%), respectively. The pooled means of left atrial (LA)-GLS (corresponding to total strain, passive strain, and active strain) were 34.9% (95% CI: 29.6%-40.2%), 21.3% (95% CI: 16.6%-26.1%) and 14.3% (95% CI: 11.8%-16.8%), respectively. The pooled means of right ventricular (RV)-GLS and right atrial global longitudinal total strain were -24.0% (95% CI: -25.8% to -22.1%) and 36.3% (95% CI: 15.5%-57.0%), respectively. Meta-regression identified field strength (P < 0.001; I2 = 98.6%) and FT vendor (P < 0.001; I2 = 98.5%) as significant confounders contributing to heterogeneity of LV-GLS. The variations of LA-GLSactive were associated with regional distribution (P < 0.001; I2 = 97.3%) and FT vendor (P < 0.001; I2 = 97.4%). Differences in FT vendor were attributed to variations of LV-GCS and RV-GLS (P = 0.02; I2 = 98.8% and P = 0.01; I2 = 93.8%).

CONCLUSIONS

This study demonstrated the normal values of CMR-FT strain parameters in all 4 cardiac chambers in healthy subjects. Differences in FT vendor contributed to the heterogeneity of LV-GLS, LV-GCS, LA-GLSactive, and RV-GLS, whereas sex, age, and MR vendor had no effect on the normal values of CMR-FT strain measurements.

Feature-Tracking Strain Parameters Differ Between Highly Accelerated and Conventional Acquisitions: A Multisoftware Assessment

BACKGROUND

Cardiac magnetic resonance imaging protocols have been adapted to fit the needs for faster, more efficient acquisitions, resulting in the development of highly accelerated, compressed sensing-based (CS) sequences. The aim of this study was to evaluate intersoftware and interacquisition differences for postprocessing software applied to both CS and conventional cine sequences.

MATERIALS AND METHODS

A total of 106 individuals (66 healthy volunteers, 40 patients with dilated cardiomyopathy, 51% female, 38±17 y) underwent cardiac magnetic resonance at 3T with retrospectively gated conventional cine and CS sequences. Postprocessing was performed using 2 commercially available software solutions and 1 research prototype from 3 different developers. The agreement of clinical and feature-tracking strain parameters between software solutions and acquisition types was assessed by Bland-Altmann analyses and intraclass correlation coefficients. Differences between softwares and acquisitions were assessed using Kruskal-Wallis analysis of variances. In addition, receiver operating characteristic curve-derived cutoffs were used to evaluate whether sequence-specific cutoffs influence disease classification.

RESULTS

There were significant intersoftware ( P <0.002 for all except LV end-diastolic volume per body surface area) and interacquisition differences ( P <0.02 for all except end-diastolic volume per body surface area from Neosoft, left ventricular mass per body surface area from cvi42 and TrufiStrain and global circumferential strain from Neosoft). However, the intraclass correlation coefficients between acquisitions were strong-to-excellent for all parameters (all ≥0.81). In comparing individual softwares to a pooled mean, Bland-Altmann analyses revealed smaller magnitudes of bias for cine acquisition than for CS acquisition. In addition, the application of conventional cutoffs to CS measurements did not result in the false reclassification of patients.

CONCLUSION

Significantly lower magnitudes of strain and volumetric parameters were observed in retrospectively gated CS acquisitions, despite strong-to-excellent agreement amongst software solutions and acquisition types. It remains important to be aware of the acquisition type in the context of follow-up examinations, where different cutoffs might lead to misclassifications.

Comparing Strain Assessment in Compressed Sensing and Conventional Cine MRI

The aim of this study is to assess the feasibility of compressed sensing (CS) acceleration methods compared to conventional segmented cine (Seg) cardiac magnetic resonance (CMR) for evaluating left ventricular (LV) function and strain by feature tracking (FT). In this prospective study, 45 healthy volunteers underwent CMR imaging used Seg, threefold (CS3), fourfold (CS4), and eightfold (CS8) CS acceleration. Cine images were scored for quality (1-5 scale). LV volumetric and functional parameters and global longitudinal (GLS), circumferential (GCS), and radial strains (GRS) were quantified. LV volumetric and functional parameters exhibited no differences between Seg and all CS cines (all P > 0.05). The strains were similar for Seg, CS3, and CS4 (all P > 0.05). Similarly, no significant differences were observed in GRS and GCS between Seg and CS8 (all P > 0.05), but the global longitudinal strain was significantly lower for CS8 versus Seg (P < 0.001). Image quality declined with CS acceleration, especially in long-axis views with CS8. CS cine MRI at acceleration factor 4 maintained good image quality and accurate measurements of LV function and strain, although there was a slight reduction in the quality of long-axis images and GLS with CS8. CS acceleration up to a factor of 4 enabled fast CMR evaluations, making it suitable for clinical use.

The effects of flip angle and gadolinium contrast agent on single breath-hold compressed sensing cardiac magnetic resonance cine for biventricular global strain assessment

Background

Due to its potential to significantly reduce scanning time while delivering accurate results for cardiac volume function, compressed sensing (CS) has gained traction in cardiovascular magnetic resonance (CMR) cine. However, further investigation is necessary to explore its feasibility and impact on myocardial strain results.

Materials and methods

A total of 102 participants [75 men, 46.5 ± 17.1 (SD) years] were included in this study. Each patient underwent four consecutive cine sequences with the same slice localization, including the reference multi-breath-hold balanced steady-state free precession (bSSFPref) cine, the CS cine with the same flip angle as bSSFPref before (CS45) and after (eCS45) contrast enhancement, and the CS cine (eCS70) with a 70-degree flip angle after contrast enhancement. Biventricular strain parameters were derived from cine images. Two-tailed paired t-tests were used for data analysis.

Results

Global radial strain (GRS), global circumferential strain (GCS), and global longitudinal strain (GLS) were observed to be significantly lower in comparison to those obtained from bSSFPref sequences for both the right and left ventricles (all p < 0.001). No significant difference was observed on biventricular GRS-LAX (long-axis) and GLS values derived from enhanced and unenhanced CS cine sequences with the same flip angle, but remarkable reductions were noted in GRS-SAX (short-axis) and GCS values (p < 0.001). After contrast injection, a larger flip angle caused a significant elevation in left ventricular strain results (p < 0.001) but did not affect the right ventricle. The increase in flip angle appeared to compensate for contrast agent affection on left ventricular GRS-SAX, GCS values, and right ventricular GRS-LAX, GLS values.

Conclusion

Despite incorporating gadolinium contrast agents and applying larger flip angles, single breath-hold CS cine sequences consistently yielded diminished strain values for both ventricles when compared with conventional cine sequences. Prior to employing this single breath-hold CS cine sequence to refine the clinical CMR examination procedure, it is crucial to consider its impact on myocardial strain results.

Imaging in patients with cardiovascular implantable electronic devices: part 1-imaging before and during device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

More than 500 000 cardiovascular implantable electronic devices (CIEDs) are implanted in the European Society of Cardiology countries each year. The role of cardiovascular imaging in patients being considered for CIED is distinctly different from imaging in CIED recipients. In the former group, imaging can help identify specific or potentially reversible causes of heart block, the underlying tissue characteristics associated with malignant arrhythmias, and the mechanical consequences of conduction delays and can also aid challenging lead placements. On the other hand, cardiovascular imaging is required in CIED recipients for standard indications and to assess the response to device implantation, to diagnose immediate and delayed complications after implantation, and to guide device optimization. The present clinical consensus statement (Part 1) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients undergoing implantation of conventional pacemakers, cardioverter defibrillators, and resynchronization therapy devices. The document summarizes the existing evidence regarding the use of imaging in patient selection and during the implantation procedure and also underlines gaps in evidence in the field. The role of imaging after CIED implantation is discussed in the second document (Part 2).

Comparison of classical Fabry and its p.D313Y and p.A143T variants by cardiac T1 mapping, LGE and feature tracking myocardial strain

Cardiac manifestation of classical Fabry disease (cFD) varies with sex and presence of left ventricular hypertrophy. p.D313Y/p.A143T variants (vFD) represent milder late-onset phenotypes, however, data on vFD are scarce. Patients with FD (cFD = 37;vFD = 14) and 14 healthy controls underwent 1.5 T CMR including Cine, LGE, native T1 mapping(nT1) and myocardial strain(CMR-FT). CMR-FT was assessed using ventricular longitudinal, circumferential, radial (LV-GLS/RV-GLS, LV-GCS/LV-GRS), and atrial longitudinal strain (LA/RA_Total, LA/RA_Conduit, LA/RA_Booster). In cFD reduced myocardial strain (LV-GLS: -20 ± 4 vs. -24 ± 3%,p = 0.007; LV-GCS: -20 ± 4 vs. -26 ± 4%,p = 0.002, LA _Total -GLS: 29 ± 10 vs. 37 ± 6%,p = 0.007; LA _Conduit -GLS: 15 ± 10 vs. 23 ± 5%,p = 0.003) and nT1 values (951 ± 51 ms vs. 1036 ± 20 ms, p < 0.001) were observed compared to controls. In vFD findings were comparable to controls. LV-GCS provided the closest Area under the curve (AUC) to nT1 (0.84 vs. 0.92, p > 0.05) for discrimination of cFD versus controls. Significantly lower LV-GLS/LV-GCS was found in male compared to female cFD (-19 ± 4 vs. -22 ± 4%, p = 0.03). In six non-hypertrophied female cFD with normal nT1 LA_Total -GLS was the only discriminating parameter with an accuracy of 86%. LV-GLS, LV-GCS and LA_Total -GLS can detect impaired cardiac mechanics of cFD besides nT1. LA_Total -GLS might identify non-hypertrophied female cFD. Variants p.D313Y/p.A143T did not reveal cardiac involvement by multiparametric CMR.

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.

Effects of spatial and temporal resolution on cardiovascular magnetic resonance feature tracking measurements using a simple realistic numerical phantom

OBJECTIVES

To develop a single-slice numerical phantom with known myocardial motion, at several temporal and in-plane spatial resolutions, for testing and comparison of Cardiovascular Magnetic Resonance (CMR) feature tracking (FT) software.

METHODS

The phantom was developed based on CMR acquisitions of one volunteer (acquired cine, tagging cine, T1 map, T2 map, proton density weighted image). The numerical MRI simulator JEMRIS was used, and the phantom was generated at several in-plane spatial resolutions (1.4 × 1.4 mm2 to 3.0 × 3.0 mm2) and temporal resolutions (20 to 40 cardiac phases). Two feature tracking software packages were tested: Medical Image Tracking Toolbox (MITT) and two versions of cvi42 (v5.3.8 and v5.13.7). The effect of resolution on strain results was investigated with reference to ground-truth radial and circumferential strain.

RESULTS

Peak radial strain was consistently undermeasured more for cvi42 v5.13.7 than for v5.3.8. Increased pixel size produced a trend of increased difference from ground-truth peak strain, with the largest changes for cvi42 obtained using v5.13.7 between 1.4 × 1.4 mm2 and 3.0 × 3.0 mm2, at 9.17 percentage points (radial) and 8.42 percentage points (circumferential).

CONCLUSIONS

The results corroborate the presence of intervendor differences in feature tracking results and show the magnitude of strain differences between software versions.

ADVANCES IN KNOWLEDGE

This study shows how temporal and in-plane spatial resolution can affect feature tracking with reference to the ground-truth strain of a numerical phantom. Results reaffirm the need for numerical phantom development for the validation and testing of FT software.

The value of CMR Left ventricular strain analysis in evaluating ICM

The purpose of this article is to investigate the value of cardiac magnetic resonance imaging (CMR) derived left ventricular strain parameters in evaluation of ischemic cardiomyopathy (ICM). Thirty-one ICM patients and nineteen non-cardiomyopathy (non-CM) patients who performed CMR examinations during the same period were selected for this retrospective study. The basic clinical data, CMR left ventricular function parameters, left ventricular strain parameters were compared among the left ventricular ejection fraction (LVEF) preserved ICM group, the LVEF impaired ICM group and the non-CM group. The differences of MyoGCS (-21.9 ± 1.9 vs. -18.9 ± 2.7 P<0.001), MyoGLS (-20.8 ± 2.3 vs. -17.0 ± 2.9 P<0.001) and EndoGLS (-22.2 ± 3.1 vs. -17.6 ± 3.7 P<0.001) between LVEF preserved ICM group and non-CM group were statistically significant, while the differences of left heart function parameters between the two groups were not statistically significant (P > 0.05). The left ventricular strain analysis can be used to assess cardiac functional and morphological alterations in ICM patients prior to changes of left ventricular function parameters, which has high clinical significance.

Differential Adaptation of Biventricular Myocardial Kinetic Energy in Patients With Repaired Tetralogy of Fallot Assessed by MR Tissue Phase Mapping

BACKGROUND

The myocardial kinetic energy (KE) and its association with pulmonary regurgitation (PR) have yet to be investigated in repaired tetralogy of Fallot (rTOF) patients.

PURPOSE

To evaluate the adaptation of myocardial KE in rTOF patients by tissue phase mapping (TPM).

STUDY TYPE

Prospective.

POPULATION

A total of 49 rTOF patients (23 ± 5 years old; male = 32), 47 normal controls (22 ± 1 year old; male = 29).

FIELD STRENGTH/SEQUENCE

3-T/2D dark-blood three-directional velocity-encoded gradient-echo sequence.

ASSESSMENT

Left and right ventricle (LV, RV) myocardial KE in radial (KE_r ), circumferential (KE_ø ), longitudinal (KE_z ) directions. The proportions of KE in each direction to the sum of all KE (KE_røz ): %KE_r , %KE_ø , %KE_z . PR fraction.

STATISTICAL TEST

Student's t test, multivariable regression. Statistical significance: P < 0.05.

RESULTS

In rTOF group, LV KE_z remained normal in systole (P = 0.565) and diastole (P = 0.210), whereas diastolic LV %KE_z (62% ± 14% vs. 72% ± 7%) and systolic LV %KE_ø (9% ± 6% vs. 20% ± 7%) were significantly decreased. The KE_r and %KE_r of both ventricles significantly increased in the rTOF group (RV in diastole: 6 ± 3 vs. 3 ± 1 μJ and 54% ± 13% vs. 27% ± 7%). The rTOF group exhibited significantly higher RV/LV ratios of %KE_r (systole: 1.3 ± 0.3 vs. 1.0 ± 0.3) and %KE_ø (systole: 1.6 ± 0.8 vs. 1.0 ± 0.3) and significantly lower ratios of %KE_z in systole (0.7 ± 0.2 vs. 1.0 ± 0.1) and diastole (0.5 ± 0.2 vs. 0.9 ± 0.1). In multivariable regression analysis, the RV peak systolic KE_røz , RV systolic KE_z , and LV diastolic %KE_ø were independently associated with PR fraction in the rTOF group (adjusted R²  = 0.479).

DATA CONCLUSION

In rTOF patients, the adaptation of the KE proportion occurred earlier than that of the KE amplitude, and the biventricular balance of %KE was disrupted. PR may cause differential KE adaptation in RV and LV. TPM-derived KE may be useful in investigation of myocardial adaptation in rTOF patients.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 3.

Significance of Cardiac Magnetic Resonance Feature Tracking of the Right Ventricle in Predicting Subclinical Dysfunction in Patients with Thalassemia Major

In patients with thalassemia major (TM), cardiac magnetic resonance feature-tracking (CMR-FT) has been shown to be an effective method for diagnosing subclinical left ventricular (LV) dysfunction. This study aimed to determine whether CMR-FT could detect abnormal RV dysfunction in patients with a normal right ventricular ejection fraction (RVEF). We performed a retrospective analysis of TM patients admitted to Dubai’s Rashid Hospital between July 2019 and March 2021. The inclusion criteria were TM patients with SSFP cine with T2* (T2*-weighted imaging), while exclusion criteria included any other cardiovascular disease. When there was no myocardial iron overload (MIO) (T2* ≥ 20 ms) and when there was significant MIO (T2* < 20 ms), the CMR-FT was used to correlate with EF. Among the 89 participants, there were 46 men (51.7%) and 43 women (48.3%), with a mean age of 26.14 ± 7.4 years (range from 10 to 48 years). Forty-six patients (51.69%) did not have MIO, while 43 individuals did (48.31%). Thirty-nine patients (32.6%) were diagnosed with severe MIO, while seventeen (19.1%) were diagnosed with mild to moderate MIO. A significant correlation existed between RVEF and T2* values (r = 0.274, p = 0.014) and between left ventricular ejection fraction (LVEF) and T2* values (r = 0.256, p = 0.022). Using a multiple logistic regression model with predictors such as right ventricular longitudinal strain (RVGLS), LV ejection fraction (LV EF), and hemoglobin, abnormal myocardial iron overload can be predicted. This model demonstrates an AUC of 78.3%, a sensitivity of 72%, and a specificity of 76%. In the group with preserved RVEF > 53%, the left ventricular radial strain (LVGRS) (p = 0.001), right ventricular radial strain (RVGRS) (p = 0.000), and right ventricular basal circumferential strain (RVGCS-basal) (p = 0.000) CMR-FT strain values are significantly lower than those of the control group (p > 0.05). There was no significant correlation between the LVGLS and T2*. RVGLS was ranked among the most accurate predictors of abnormal myocardial iron overload. The LVGRS, RVGRS, and RVGCS-basal CMR-FT strain values were the best predictors of subclinical RV dysfunction in the group with preserved RVEF. The most accurate way to diagnose MIO is still T2*, but FT-strain can help us figure out how MIO affects the myocardium from a pathophysiological point of view.

Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

Comparison of DeepStrain and Feature Tracking for Cardiac MRI Strain Analysis

BACKGROUND

Myocardial feature tracking (FT) provides a comprehensive analysis of myocardial deformation from cine balanced steady-state free-precession images (bSSFP). However, FT remains time-consuming, precluding its clinical adoption.

PURPOSE

To compare left-ventricular global radial strain (GRS) and global circumferential strain (GCS) values measured using automated DeepStrain analysis of short-axis cine images to those calculated using manual commercially available FT analysis.

STUDY TYPE

Retrospective, single-center.

POPULATION

A total of 30 healthy subjects and 120 patients with cardiac disease for DeepStrain development. For evaluation, 47 healthy subjects (36 male, 53 ± 5 years) and 533 patients who had undergone a clinical cardiac MRI (373 male, 59 ± 14 years). FIELD STRENGTH/SEQUENCE: bSSFP sequence at 1.5 T (Phillips) and 3 T (Siemens).

ASSESSMENT

Automated DeepStrain measurements of GRS and GCS were compared to commercially available FT (Circle, cvi42) measures obtained by readers with 1 year and 3 years of experience. Comparisons were performed overall and stratified by scanner manufacturer.

STATISTICAL TESTS

Paired t-test, linear regression slope, Pearson correlation coefficient (r).

RESULTS

Overall, FT and DeepStrain measurements of GCS were not significantly different (P = 0.207), but measures of GRS were significantly different. Measurements of GRS from Philips (slope = 1.06 [1.03 1.08], r = 0.85) and Siemens (slope = 1.04 [0.99 1.09], r = 0.83) data showed a very strong correlation and agreement between techniques. Measurements of GCS from Philips (slope = 0.98 [0.98 1.01], r = 0.91) and Siemens (slope = 1.0 [0.96 1.03], r = 0.88) data similarly showed a very strong correlation. The average analysis time per subject was 4.1 ± 1.2 minutes for FT and 34.7 ± 3.3 seconds for DeepStrain, representing a 7-fold reduction in analysis time.

DATA CONCLUSION

This study demonstrated high correlation of myocardial GCS and GRS measurements between freely available fully automated DeepStrain and commercially available manual FT software, with substantial time-saving in the analysis.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

Cardiovascular Imaging in Cardio-Oncology: The Role of Echocardiography and Cardiac MRI in Modern Cardio-Oncology

Cardiovascular (CV) events are an increasingly common limitation of effective anticancer therapy. Over the last decade imaging has become essential to patients receiving contemporary cancer therapy. Herein we discuss the current state of CV imaging in cardio-oncology. We also provide a practical apparatus for the use of imaging in everyday cardiovascular care of oncology patients to improve outcomes for those at risk for cardiotoxicity, or with established cardiovascular disease. Finally, we consider future directions in the field given the wave of new anticancer therapies.

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.

Left Ventricular Strain Measurements Derived from MR Feature Tracking: A Head-to-Head Comparison of a Higher Temporal Resolution Method With a Conventional Method

BACKGROUND

Magnetic resonance feature tracking (MR-FT) is an imaging technique that quantifies both global and regional myocardial strain. Currently, conventional MR-FT provides a superior signal and contrast-to-noise ratio but has a relatively low temporal resolution. A higher temporal resolution MR-FT technique may provide improved results.

PURPOSE

To explore the impact of higher temporal resolution on left ventricular (LV) myocardial strain measurements using MR-FT.

STUDY TYPE

Prospective.

POPULATION

One hundred and fifty-three participants including five healthy subjects and patients with various cardiac diseases referred to MR for cardiac assessment.

FIELD STRENGTH

3 T, balanced steady-state free precession sequence with and without compressed sensing (temporal resolution: 10 msec and 40 msec, respectively).

ASSESSMENT

Conventional (40 msec) and higher (10 msec) temporal resolution data were acquired in all subjects during the same scanning session. Global circumferential strain (GCS), global longitudinal strain (GLS), and global radial strain (GRS) as well as peak systolic and diastolic strain rates (SRs) were measured by MR-FT and compared between the two temporal resolutions. We also performed subgroup analyses according to heart rates (HRs) and LV ejection fraction (LVEF).

STATISTICAL TESTS

Paired t-test, Wilcoxon signed-rank test, linear regression analyses, Bland-Altman plots. A P value <0.05 was considered to be statistically significant.

RESULTS

GCS and GRS were significantly higher in the 10-msec temporal resolution studies compared to the 40-msec temporal resolution studies (GCS: -13.00 ± 6.58% vs. -12.51 ± 5.76%; GRS: 21.97 ± 14.54% vs. 20.62 ± 12.52%). In the subgroup analyses, significantly higher GLS, GCS, and GRS values were obtained in subjects with LVEF ≥50%, and significantly higher GCS and GRS values were obtained in subjects with HRs <70 bpm when assessed with the 10-msec vs. the 40-msec temporal resolutions. All the peak systolic and diastolic SRs were significantly higher in the higher temporal resolution acquisitions. This was also true for all subgroups.

DATA CONCLUSIONS

Higher temporal resolution resulted in significantly higher cardiac strain and SR values using MR-FT and could be beneficial, particularly in patients with LVEF ≥50% and HR <70 bpm.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.

Longitudinal CMR assessment of cardiac global longitudinal strain and hemodynamic forces in a mouse model of heart failure

To longitudinally assess left ventricle (LV) global longitudinal strain (GLS) and hemodynamic forces during the early stages of cardiac dysfunction in a mouse model of heart failure with preserved ejection fraction (HFpEF). Cardiac MRI measurements were performed in control mice (n = 6), and db/db mice (n = 7), whereby animals were scanned four times between the age of 11-15 weeks. After the first scan, the db/db animals received a doxycycline intervention to accelerate progression of HFpEF. Systolic function was evaluated based on a series of prospectively ECG-triggered short-axis CINE images acquired from base to apex. Cardiac GLS and hemodynamic forces values were evaluated based on high frame rate retrospectively gated 2-, 3-, and 4-chamber long-axis CINE images. Ejection fraction (EF) was not different between control and db/db animals, despite that cardiac output, as well as end systolic and end diastolic volume were significantly higher in control animals. Whereas GLS parameters were not significantly different between groups, hemodynamic force root mean square (RMS) values, as well as average hemodynamic forces and the ratio between hemodynamic forces in the inferolateral-anteroseptal and apical-basal direction were lower in db/db mice compared to controls. More importantly, hemodynamic forces parameters showed a significant interaction effect between time and group. Our results indicated that hemodynamic forces parameters were the only functional outcome measure that showed distinct temporal differences between groups. As such, changes in hemodynamic forces reflect early alterations in cardiac function which can be of added value in (pre)clinical research on HFpEF.

Prediction of cardiac events with non-contrast magnetic resonance feature tracking in patients with ischaemic cardiomyopathy

Aims

The aim of this study was to evaluate the prognostic value of feature tracking (FT) derived cardiac magnetic resonance (CMR) strain parameters of the left ventricle (LV)/right ventricle (RV) in ischaemic cardiomyopathy (ICM) patients treated with an implantable cardioverter‐defibrillator (ICD). Current guidelines suggest a LV‐ejection fraction ≤35% as major criterion for ICD implantation in ICM, but this is a poor predictor for arrhythmic events. Supplementary parameters are missing.

Methods and results

Ischaemic cardiomyopathy patients (n = 242), who underwent CMR imaging prior to primary and secondary implantation of ICD, were classified depending on EF ≤ 35% (n = 188) or >35% (n = 54). FT parameters were derived from steady‐state free precession cine views using dedicated software. The primary endpoint was a composite of cardiovascular mortality (CVM) and/or appropriate ICD therapy. There were no significant differences in FT‐function or LV‐/RV‐function parameters in patients with an EF ≤ 35% correlating to the primary endpoint. In patients with EF > 35%, standard CMR functional parameters, such as LV‐EF, did not reveal significant differences. However, significant differences in most FT parameters correlating to the primary endpoint were observed in this subgroup. LV‐GLS (left ventricular‐global longitudinal strain) and RV‐GRS (right ventricular‐global radial strain) revealed the best diagnostic performance in ROC curve analysis. The combination of LV‐GLS and RV‐GRS showed a sensitivity of 85% and a specificity of 76% for the prediction of future events.

Conclusions

The impact of FT derived measurements in the risk stratification of patients with ICM depends on LV function. The combination of LV‐GLS/RV‐GRS seems to be a predictor of cardiovascular mortality and/or appropriate ICD therapy in patients with EF > 35%.

Moderately trained male football players, compared to sedentary male adults, exhibit anatomical but not functional cardiac remodelling, a cross-sectional study

Background

Elite athletes have been the subject of great interest, but athletes at an intermediate level of physical activity have received less attention in respect to the presence of cardiac enlargement and/or hypertrophy. We hypothesized that playing football, often defined as demanding less endurance components than running or cycling, would still induce remodelling similar to sports with a dominating endurance component.

Methods

23 male football players, age 25+/− 3.9 yrs. underwent exercise testing, 2D- and 3D- echocardiography and cardiac magnetic resonance (CMR). The results were compared with a control group of engineering students of similar age. The athletes exercised 12 h/week and the control subjects 1 h/week, p < 0.001.

Results

The football players achieved a significantly higher maximal load at the exercise test (380 W vs 300 W, p < 0.001) as well as higher calculated maximal oxygen consumption, (49.7 vs 37.4 mL x kg^− 1 x min^− 1, p < 0.001) compared to the sedentary group. All left ventricular (LV) volumes assessed by 3DEcho and CMR, as well as CMR left atrial (LA) volume were significantly higher in the athletes (3D-LVEDV 200 vs 154 mL, CMR-LVEDV 229 vs 185 mL, CMR-LA volume 100 vs 89 mL, p < 0.001, p = 0.002 and p = 0.009 respectively). LVEF and RVEF, LV strain by CMR or by echo did not differentiate athletes from sedentary participants. Right ventricular (RV) longitudinal strain, LA and right atrial (RA) strain by CMR all showed similar results in the two groups.

Conclusion

Moderately trained intermediate level football players showed anatomical but not functional cardiac remodelling compared to sedentary males.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12947-021-00263-0.

Anterior STEMI associated with decreased strain in remote cardiac myocardium

To assess (1) global longitudinal strain (GLS) by feature tracking cardiac magnetic resonance (CMR) in the sub-acute and chronic phases after ST-elevation infarction (STEMI) and compare to GLS in healthy controls, and (2) the evolution of GLS and regional longitudinal strain (RLS) over time, and their relationship to infarct location and size. Seventy-seven patients from the CHILL-MI-trial (NCT01379261) who underwent CMR 2–6 days and 6 months after STEMI and 27 healthy controls were included for comparison. Steady state free precession (SSFP) long-axis cine images were obtained for GLS and RLS, and late gadolinium enhancement (LGE) images were obtained for infarct size quantifications. GLS was impaired in the sub-acute (− 11.8 ± 3.0%) and chronic phases (− 14.3 ± 2.9%) compared to normal GLS in controls (− 18.4 ± 2.4%; p < 0.001 for both). GLS improved from sub-acute to chronic phase (p < 0.001). GLS was to some extent determined by infarct size (sub-acute: r² = 0.2; chronic: r² = 0.2, p < 0.001). RLS was impaired in all 6 wall-regions in LAD infarctions in both the sub-acute and chronic phase, while LCx and RCA infarctions had preserved RLS in remote myocardium at both time points. Global longitudinal strain is impaired sub-acutely after STEMI and improvement is seen in the chronic phase, although not reaching normal levels. Global longitudinal strain is only moderately determined by infarct size. Regional longitudinal strain is most impaired in the infarcted region, and LAD infarctions have effects on the whole heart. This could explain why LAD infarcts are more serious than the other culprit vessel infarctions and more often cause heart failure.

Additional diagnostic value of cardiac magnetic resonance feature tracking in patients with biopsy-proven arrhythmogenic cardiomyopathy

BACKGROUND

We aim to evaluate the value of Cardiac magnetic resonance (CMR) feature tracking (CMR-FT) in addition to Task Force Criteria(TFC) in patients with (arrhythmogenic cardiomyopathy) AC biopsy-proved.

METHODS

Thirty-five patients with AC histologically proven who performed CMR with late gadolinium enhancement (LGE) acquisition were enrolled. The study population was divided in Group1 (negative CMR TFC and LV ejection fraction≥55%) and Group2 (positive CMR TFC and/or LVEF<55%) and compared to an age and gender-matched control group. CMR datasets of all patients were analyzed to calculate LV indexed end-diastolic (LVEDi) and end-systolic (LVESi) volumes and RV indexed end-diastolic (RVEDi) and end-systolic (RVESi) volumes, both LV ejection fraction (LVEF) and RV ejection fraction (RVEF). Moreover, LV and RV global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain were measured.

RESULTS

The AC patients showed both higher LVEDi (p:0.002) and RVEDi (p:0.017) and lower LVEF (p: 0.016) as compared to control patients. Moreover, AC patients showed impaired LV-GLS (p < 0.001), LV-GRS (p < 0.001), LV-GCS (p < 0.001) and RV-GRS (p:0.026) as compared to control subjects. Group1 patients showed a significant reduction of LV-GRS (p < 0.05) and LV-GCS p < 0.01) as compared to control subjects. At univariate analysis LV-GCS was the most discriminatory parameter between Group1 vs heathy subjects with an optimal cut-off of -15.8 (Sensitivity: 74%; Specificity: 10%).

CONCLUSIONS

In patients with AC biopsy-proven, CMR-FT could improve the diagnostic yield in the subset of patients who results negative for imaging TFC criteria resulting as useful gatekeeper for indication of myocardial biopsy in case of equivocal clinical and imaging presentation.

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.

Left ventricle motion estimation for cine MR images using sparse representation with shape constraint

PURPOSE

To propose a left ventricle (LV) motion estimation method based on sparse representation, in order to handle the spatial-varying intensity distortions caused by tissue deformation.

METHODS

For each myocardial landmark, an adaptive dictionary was generated by learning transformations from a training dataset. Then the landmark was tracked using sparse representation. Next, a point distribution model was applied to the overall tracking results. Finally, the dense displacement field of the LV myocardium was estimated based on the correspondence between each landmark. Using the dense displacement field estimated, the circumferential strain was calculated to assess the myocardial function. The performance of the proposed method was quantified by the average perpendicular distance (APD), the Dice metric, and the mean symmetric contour distance (SCD).

RESULTS

Comparing to the state-of-the-art techniques, the smallest value of APD and SCD, and the highest value of Dice can be obtained using the proposed method, for three public cardiac datasets. Moreover, the mean value of strain difference between the proposed method and the commercial software Medis Suite MR was -0.01, while the intraclass correlation coefficient between these two methods was 0.91.

CONCLUSIONS

The proposed method could estimate the dense displacement field of the LV accurately, which outperforms other state-of-the-art techniques. The circumferential strain derived from the proposed method was in excellent agreement with that derived from the Medis Suite MR software, while segmental strain abnormalities were detected for most of the subjects with heart diseases, which indicates the potential of the proposed method for clinical usage.

Multivendor comparison of global and regional 2D cardiovascular magnetic resonance feature tracking strains vs tissue tagging at 3T

BACKGROUND

Cardiovascular magnetic resonance (CMR) 2D feature tracking (FT) left ventricular (LV) myocardial strain has seen widespread use to characterize myocardial deformation. Yet, validation of CMR FT measurements remains scarce, particularly for regional strain. Therefore, we aimed to perform intervendor comparison of 3 different FT software against tagging.

METHODS

In 61 subjects (18 healthy subjects, 18 patients with chronic myocardial infarction, 15 with dilated cardiomyopathy, and 10 with LV hypertrophy due to hypertrophic cardiomyopathy or aortic stenosis) were prospectively compared global (G) and regional transmural peak-systolic Lagrangian longitudinal (LS), circumferential (CS) and radial strains (RS) by 3 FT software (cvi42, Segment, and Tomtec) among each other and with tagging at 3T. We also evaluated the ability of regional LS, CS, and RS by different FT software vs tagging to identify late gadolinium enhancement (LGE) in the 18 infarct patients.

RESULTS

GLS and GCS by all 3 software had an excellent agreement among each other (ICC = 0.94-0.98 for GLS and ICC = 0.96-0.98 for GCS respectively) and against tagging (ICC = 0.92-0.94 for GLS and ICC = 0.88-0.91 for GCS respectively), while GRS showed inconsistent agreement between vendors (ICC 0.10-0.81). For regional LS, the agreement was good (ICC = 0.68) between 2 vendors but less vs the 3rd (ICC 0.50-0.59) and moderate to poor (ICC 0.44-0.47) between all three FT software and tagging. Also, for regional CS agreement between 2 software was higher (ICC = 0.80) than against the 3rd (ICC = 0.58-0.60), and both better agreed with tagging (ICC = 0.70-0.72) than the 3rd (ICC = 0.57). Regional RS had more variation in the agreement between methods ranging from good (ICC = 0.75) to poor (ICC = 0.05). Finally, the accuracy of scar detection by regional strains differed among the 3 FT software. While the accuracy of regional LS was similar, CS by one software was less accurate (AUC 0.68) than tagging (AUC 0.80, p < 0.006) and RS less accurate (AUC 0.578) than the other two (AUC 0.76 and 0.73, p < 0.02) to discriminate segments with LGE.

CONCLUSIONS

We confirm good agreement of CMR FT and little intervendor difference for GLS and GCS evaluation, with variable agreement for GRS. For regional strain evaluation, intervendor difference was larger, especially for RS, and the diagnostic performance varied more substantially among different vendors for regional strain analysis.

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking-All About the Left Ventricle?

Purpose of Review

Cardiac magnetic resonance-feature-tracking (CMR-FT)-based deformation analyses are key tools of cardiovascular imaging and applications in heart failure (HF) diagnostics are expanding. In this review, we outline the current range of application with diagnostic and prognostic implications and provide perspectives on future trends of this technique.

Recent Findings

By applying CMR-FT in different cardiovascular diseases, increasing evidence proves CMR-FT-derived parameters as powerful diagnostic and prognostic imaging biomarkers within the HF continuum partly outperforming traditional clinical values like left ventricular ejection fraction. Importantly, HF diagnostics and deformation analyses by CMR-FT are feasible far beyond sole left ventricular performance evaluation underlining the holistic nature and accuracy of this imaging approach.

Summary

As an established and continuously evolving technique with strong prognostic implications, CMR-FT deformation analyses enable comprehensive cardiac performance quantification of all cardiac chambers.

Cardiac Magnetic Resonance Feature Tracking: A Novel Method to Assess Left Ventricular Three-Dimensional Strain Mechanics After Chronic Myocardial Infarction

RATIONALE AND OBJECTIVES

This study was designed to assess left ventricular deformation after chronic myocardial infarction (CMI) using cardiac magnetic resonance feature tracking (CMR-FT) technology, and analyze its relationship with left ventricular ejection fraction (LVEF) and infarcted transmurality.

MATERIALS AND METHODS

Ninety-six patients with CMI and 72 controls underwent 3.0 T CMR scanning. Strain parameters were measured by dedicated software, including global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS), segmental peak longitudinal strain (PLS), peak circumferential strain (PCS), and peak radial strain (PRS). All enhanced myocardium segments were divided into subendocardial infarction (SI) and transmural infarction (TI) group. Pearson, intraclass correlation coefficient and receiver operating characteristic analysis were performed to compare the parameters' mean values between SI and TI groups.

RESULTS

GPLS, GPRS, and GPCS in CMI group were significantly decreased comparing with control group. PRS and PCS in TI group were significantly lower than those in SI group, whereas no statistical difference was observed in PLS. In Pearson correlation analysis, LVEF was strongly correlated with GPLS, GPRS, and GPCS in CMI patients. Additionally, excellent reproducibility of all strain parameters was observed. In receiver operating characteristic analysis, segmental PRS and PCS might differentiate SI from TI with higher diagnostic efficiency (p < 0.05), while PLS was less valuable (p > 0.05).

CONCLUSION

CMR-FT could noninvasively and quantitatively assess global and regional myocardial strain in CMI patients with excellent reproducibility and strong correlation with LVEF. Additionally, segmental myocardial strain parameters indicate potential clinical value in differentiating myocardial infarction subtype.

Left ventricular myocardial strain quantification with two- and three-dimensional cardiovascular magnetic resonance based tissue tracking

Background

Cardiovascular magnetic resonance based tissue tracking (CMR-TT) was reported to provide detailed insight into left ventricular (LV) contractile function and deformation with both of two- and three-dimensional (2/3D) algorithms. This study was designed to investigate the feasibility and reproducibility of these two techniques for measuring LV global and segmental strain, and establish gender- and age-related reference values of global multi-dimensional peak strains among large healthy population.

Methods

We retrospectively recruited 150 healthy volunteers (75 males/females) and divided them into three age groups (G_20-40, G_41-60 and G_61-80). LV global mean and peak strains as well as segmental strains in radial, circumferential and longitudinal directions were derived from post-hoc 2/3D CMR-TT analysis of standard steady-state free precession (SSFP) cine images acquired at 1.5T field strength.

Results

Both 2D and 3D CMR-TT modalities enable the tracking of LV myocardial tissues and generate global and segmental strain data. By comparison, 3D CMR-TT was more feasible in measuring segmental deformation since it could generate values at all segments. The amplitudes of LV 3D global peak strain were the smallest among those of 2/3D corresponding global mean or peak strains except in the radial direction, and was highly correlated with 2D global mean strains (correlation coefficient r=0.71-0.90), 2D global peak strains (r=0.75-0.89) and 3D global mean strains (all r=0.99). In healthy cohort, LV 3D global peak values were 44.4%±13.0% for radial, -17.0%±2.7% for circumferential and -15.4%±2.3% for longitudinal strain. Females showed significantly larger amplitude of strains than males, especially in G_61-80 (P<0.05). The subjects in G_61-80 showed larger amplitude of strains than the volunteers in younger groups. The intra- and inter-observer agreement of 2/3D CMR-TT analysis in evaluating LV myocardial global deformation was better than segmental measurement.

Conclusions

CMR-TT is a feasible and reproducible technique for assessing LV myocardial deformation, especially at the global level. The establishment of specific reference values of LV global and segmental systolic strains and the investigation of dimension-, gender- and age-related differences provide a fundamental insight into the features of LV contraction and works as an essential step in clinical routine.

CMR feature tracking strain patterns and their association with circulating cardiac biomarkers in patients with hypertrophic cardiomyopathy

Aims

CMR feature tracking strain (CMR-FT) provides prognostic information. However, there is a paucity of data in hypertrophic cardiomyopathy (HCM). We sought to analyze global CMR-FT parameters in all four cardiac chambers and to assess associations with NT-proBNP and cardiac troponin T (hsTnT) in patients with HCM.

Methods

This retrospective study included 144 HCM patients and 16 healthy controls with CMR at 1.5 T. Analyses were performed on standard steady-state free precession cine (SSFP) CMR data using a commercially available software. Global left ventricular (LV) strain was assessed as longitudinal (LV_LAX-GLS), circumferential (LV_LAX-GCS) and radial strain (LV_LAX-GRS) on long -axis (LAX) and as LV_SAX-GCS and LV_SAX-GRS on short- axis (SAX). Right ventricular (RV-GLS), left atrial (LA-GLS) and right atrial (RA-GLS) strain were assessed on LAX.

Results

We found LV_LAX-GLS [− 18.9 (− 22.0, − 16.0), − 23.5 (− 25.5, − 22.0) %, p = 0.0001), LV_SAX-GRS [86.8 (65.9–115.5), 119.6 (91.3–143.7) %, p = 0.001] and LA_LAX-GLS [LA_2CH-GLS 29.2 (19.1–37.7), LA_2CH-GLS 38.2 (34.3–47.1) %, p = 0.0036; LA_4CH-GLS 22.4 (14.6–30.7) vs. LA_4CH-GLS 33.4 (28.4–37.3) %, p = 0.0033] to be impaired in HCM compared to healthy controls despite normal LVEF. Furthermore, LV and LA strain parameters were impaired in HCM with elevated NT-proBNP and/or hsTnT, despite preserved LVEF compared to HCM with normal biomarker levels. There was a moderate correlation of LV and LA CMR-FT with levels of NT-proBNP and hsTnT.

Conclusion

CMR-FT reveals LV and LA dysfunction in HCM despite normal LVEF. The association between impaired LV strain and elevated NT-proBNP and hsTnT indicates a link between unapparent functional abnormalities and disease severity in HCM.

Graphic abstract

Typical CMR-FT findings in patients with hypertrophic cardiomyopathy

CMR for myocardial characterization in ischemic heart disease: state-of-the-art and future developments

Ischemic heart disease and its sequelae are one of the major contributors to morbidity and mortality worldwide. Over the last decades, technological developments have strengthened the role of noninvasive imaging for detection, risk stratification, and management of patients with ischemic heart disease. Cardiac magnetic resonance (CMR) imaging incorporates both functional and morphological characterization of the heart to determine presence, acuteness, and severity of ischemic heart disease by evaluating myocardial wall motion and function, the presence and extent of myocardial edema, ischemia, and scarring. Currently established clinical protocols have already demonstrated their diagnostic and prognostic value. Nevertheless, there are emerging imaging technologies that provide additional information based on advanced quantification of imaging biomarkers and improved diagnostic accuracy, therefore potentially allowing reduction or avoidance of contrast and/or stressor agents. The aim of this review is to summarize the current state of the art of CMR imaging for ischemic heart disease and to provide insights into promising future developments.

Deformation Parameters of the Heart in Endurance Athletes and in Patients with Dilated Cardiomyopathy-A Cardiac Magnetic Resonance Study

A better understanding of the left ventricle (LV) and right ventricle (RV) functioning would help with the differentiation between athlete's heart and dilated cardiomyopathy (DCM). We aimed to analyse deformation parameters in endurance athletes relative to patients with DCM using cardiac magnetic resonance feature tracking (CMR-FT). The study included males of a similar age: 22 ultramarathon runners, 22 patients with DCM and 21 sedentary healthy controls (41 ± 9 years). The analysed parameters were peak LV global longitudinal, circumferential and radial strains (GLS, GCS and GRS, respectively); peak LV torsion; peak RV GLS. The peak LV GLS was similar in controls and athletes, but lower in DCM (p < 0.0001). Peak LV GCS and GRS decreased from controls to DCM (both p < 0.0001). The best value for differentiation between DCM and other groups was found for the LV ejection fraction (area under the curve (AUC) = 0.990, p = 0.0001, with 90.9% sensitivity and 100% specificity for ≤53%) and the peak LV GRS diastolic rate (AUC = 0.987, p = 0.0001, with 100% sensitivity and 88.4% specificity for >-1.27 s^-1). The peak LV GRS diastolic rate was the only independent predictor of DCM (p = 0.003). Distinctive deformation patterns that were typical for each of the analysed groups existed and can help to differentiate between athlete's heart, a nonathletic heart and a dilated cardiomyopathy.

Feasibility of single-shot compressed sensing cine imaging for analysis of left ventricular function and strain in cardiac MRI

AIM

To compare single-shot compressed sensing (CS) cine imaging with conventional segmented cine imaging for reliable quantification of left ventricular (LV) volume and strain assessment during cardiac magnetic resonance imaging (CMRI).

MATERIALS AND METHODS

Thirty-seven participants underwent both single-shot CS and conventional segmented cines that covered the entire LV. LV volumetric and strain values were obtained. LV volumes, global strain, the standard deviation of time to peak strain (SD-TPS) in the radial, longitudinal, and circumferential directions were compared using the Student's t-test and intraclass correlation coefficient (ICC). Interobserver and intra-observer variabilities of the LV strain values for the two cines method were determined using ICC.

RESULTS

Single-shot CS cine-derived LV volumes and myocardial mass measurements correlated strongly with segmented cines (ICC >0.798) and minor systematic end-systolic volume overestimations resulting in ejection fraction underestimations. Single-shot CS cine-derived global strain and SD-TPS were poorly to moderately correlated with segmented cines (ICC from 0.045-0.706). All global strain values derived from single-shot CS cines were underestimated compared with segmented cine-derived values; however, no significant differences in radial and longitudinal SD-TPS between the two cines were found. Among the patient-related factors, heart rate was a strong predictive factor of global longitudinal strain underestimations (p=0.039) in the CS cines. Inter- and intra-observer LV strain variabilities derived from CS and segmented cines were good to excellent.

CONCLUSION

Single-shot CS cine CMRI is feasible for the quantitative assessment of LV function. Currently, strain values derived from the two techniques are not interchangeable.

Cardiac magnetic resonance imaging: insights into developmental programming and its consequences for aging

Cardiovascular diseases (CVD) are important consequences of adverse perinatal conditions such as fetal hypoxia and maternal malnutrition. Cardiac magnetic resonance imaging (CMR) can produce a wealth of physiological information related to the development of the heart. This review outlines the current state of CMR technologies and describes the physiological biomarkers that can be measured. These phenotypes include impaired ventricular and atrial function, maladaptive ventricular remodeling, and the proliferation of myocardial steatosis and fibrosis. The discussion outlines the applications of CMR to understanding the developmental pathways leading to impaired cardiac function. The use of CMR, both in animal models of developmental programming and in human studies, is described. Specific examples are given in a baboon model of intrauterine growth restriction (IUGR). CMR offers great potential as a tool for understanding the sequence of dysfunctional adaptations of developmental origin that can affect the human cardiovascular system.

Clinical validation of three cardiovascular magnetic resonance techniques to measure strain and torsion in patients with suspected coronary artery disease

BACKGROUND

Several cardiovascular magnetic resonance (CMR) techniques can measure myocardial strain and torsion with high accuracy. The purpose of this study was to compare displacement encoding with stimulated echoes (DENSE), tagging and feature tracking (FT) for measuring circumferential and radial myocardial strain and myocardial torsion in order to assess myocardial function and infarct scar burden both at a global and at a segmental level.

METHOD

116 patients with a high likelihood of coronary artery disease (European SCORE > 15%) underwent CMR examination including cine images, tagging, DENSE and late gadolinium enhancement (LGE) in the short axis direction. In total, 97 patients had signs of myocardial disease and 19 had no abnormalities in terms of left ventricular (LV) wall mass index, LV ejection fraction, wall motion, LGE or a history of myocardial infarction. Thirty-four patients had myocardial infarct scar with a transmural LGE extent (transmurality) that exceeded 50% of the wall thickness in at least one segment. Global circumferential strain (GCS) and global radial strain (GRS) was analyzed using FT of cine loops, deformation of tag lines or DENSE displacement.

RESULTS

DENSE and tagging both showed high sensitivity (82% and 71%) at a specificity of 80% for the detection of segments with > 50% LGE transmurality, and receiver operating characteristics (ROC) analysis showed significantly higher area under the curve-values (AUC) for DENSE (0.87) than for tagging (0.83, p < 0.001) and FT (0.66, p = 0.003). GCS correlated with global LGE when determined with DENSE (r = 0.41), tagging (r = 0.37) and FT (r = 0.15). GRS had a low but significant negative correlation with LGE; DENSE r = - 0.10, FT r = - 0.07 and tagging r = - 0.16. Torsion from DENSE and tagging had a weak correlation (- 0.20 and - 0.22 respectively) with global LGE.

CONCLUSION

Circumferential strain from DENSE detected segments with > 50% scar with a higher AUC than strain determined from tagging and FT at a segmental level. GCS and torsion computed from DENSE and tagging showed similar correlation with global scar size, while when computed from FT, the correlation was lower.

Quantification of myocardial strain assessed by cardiovascular magnetic resonance feature tracking in healthy subjects-influence of segmentation and analysis software

Objectives

Quantification of myocardial deformation by feature tracking is of growing interest in cardiovascular magnetic resonance. It allows the assessment of regional myocardial function based on cine images. However, image acquisition, post-processing, and interpretation are not standardized. We aimed to assess the influence of segmentation procedure such as slice selection and different types of analysis software on values and quantification of myocardial strain in healthy adults.

Methods

Healthy volunteers were retrospectively analyzed. Post-processing was performed using CVI⁴² and TomTec. Longitudinal and radial_{Long axis (LAX)} strain were quantified using 4-chamber-view, 3-chamber-view, and 2-chamber-view. Circumferential and radial_{Short axis (SAX)} strain were assessed in basal, midventricular, and apical short-axis views and using full coverage. Global and segmental strain values were compared to each other regarding their post-processing approach and analysis software package.

Results

We screened healthy volunteers studied at 1.5 or 3.0 T and included 67 (age 44.3 ± 16.3 years, 31 females). Circumferential and radial_SAX strain values were different between a full coverage approach vs. three short slices (− 17.6 ± 1.8% vs. − 19.2 ± 2.3% and 29.1 ± 4.8% vs. 34.6 ± 7.1%). Different analysis software calculated significantly different strain values. Within the same vendor, different field strengths (− 17.0 ± 2.1% at 1.5 T vs. − 17.0 ± 1.7% at 3 T, p = 0.845) did not influence the calculated global longitudinal strain (GLS), and were similar in gender (− 17.4 ± 2.0% in females vs. − 16.6 ± 1.8% in males, p = 0.098). Circumferential and radial strain were different in females and males (circumferential strain − 18.2 ± 1.7% vs. − 17.1 ± 1.8%, p = 0.029 and radial strain 30.7 ± 4.7% vs. 27.8 ± 4.6%, p = 0.047).

Conclusions

Myocardial deformation assessed by feature tracking depends on segmentation procedure and type of analysis software. Circumferential_SAX and radial_SAX depend on the number of slices used for feature tracking analysis. As known from other imaging modalities, GLS seems to be the most stable parameter. During follow-up studies, standardized conditions should be warranted.

Trial registration Retrospectively registered

Key Points

• Myocardial deformation assessed by feature tracking depends on the segmentation procedure.

• Global myocardial strain values differ significantly among vendors.

• Standardization in post-processing using CMR feature tracking is essential.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-020-07539-5.

Cardiovascular magnetic resonance-derived left ventricular mechanics-strain, cardiac power and end-systolic elastance under various inotropic states in swine

BACKGROUND

Cardiovascular magnetic resonance (CMR) strain imaging is an established technique to quantify myocardial deformation. However, to what extent left ventricular (LV) systolic strain, and therefore LV mechanics, reflects classical hemodynamic parameters under various inotropic states is still not completely clear. Therefore, the aim of this study was to investigate the correlation of LV global strain parameters measured via CMR feature tracking (CMR-FT, based on conventional cine balanced steady state free precession (bSSFP) images) with hemodynamic parameters such as cardiac index (CI), cardiac power output (CPO) and end-systolic elastance (Ees) under various inotropic states.

METHODS

Ten anaesthetized, healthy Landrace swine were acutely instrumented closed-chest and transported to the CMR facility for measurements. After baseline measurements, two steps were performed: (1) dobutamine-stress (Dobutamine) and (2) verapamil-induced cardiovascular depression (Verapamil). During each protocol, CMR images were acquired in the short axisand apical 2Ch, 3Ch and 4Ch views. MEDIS software was utilized to analyze global longitudinal (GLS), global circumferential (GCS), and global radial strain (GRS).

RESULTS

Dobutamine significantly increased heart rate, CI, CPO and Ees, while Verapamil decreased them. Absolute values of GLS, GCS and GRS accordingly increased during Dobutamine infusion, while GLS and GCS decreased during Verapamil. Linear regression analysis showed a moderate correlation between GLS, GCS and LV hemodynamic parameters, while GRS correlated poorly. Indexing global strain parameters for indirect measures of afterload, such as mean aortic pressure or wall stress, significantly improved these correlations, with GLS indexed for wall stress reflecting LV contractility as the clinically widespread LV ejection fraction.

CONCLUSION

GLS and GCS correlate accordingly with LV hemodynamics under various inotropic states in swine. Indexing strain parameters for indirect measures of afterload substantially improves this correlation, with GLS being as good as LV ejection fraction in reflecting LV contractility. CMR-FT-strain imaging may be a quick and promising tool to characterize LV hemodynamics in patients with varying degrees of LV dysfunction.

Shear Wave Elastography Using High-Frame-Rate Imaging in the Follow-Up of Heart Transplantation Recipients

OBJECTIVES

The purpose of this study was to investigate whether propagation velocities of naturally occurring shear waves (SWs) at mitral valve closure (MVC) increase with the degree of diffuse myocardial injury (DMI) and with invasively determined LV filling pressures as a reflection of an increase in myocardial stiffness in heart transplantation (HTx) recipients.

BACKGROUND

After orthotopic HTx, allografts undergo DMI that contributes to functional impairment, especially to increased passive myocardial stiffness, which is an important pathophysiological determinant of left ventricular (LV) diastolic dysfunction. Echocardiographic SW elastography is an emerging approach for measuring myocardial stiffness in vivo. Natural SWs occur after mechanical excitation of the myocardium, for example, after MVC, and their propagation velocity is directly related to myocardial stiffness, thus providing an opportunity to assess myocardial stiffness at end-diastole.

METHODS

A total of 52 HTx recipients who underwent right heart catheterization (all) and cardiac magnetic resonance (CMR) (n = 23) during their annual check-up were prospectively enrolled. Echocardiographic SW elastography was performed in parasternal long axis views of the LV using an experimental scanner at 1,135 ± 270 frames per second. The degree of DMI was quantified with T1 mapping.

RESULTS

SW velocity at MVC correlated best with native myocardial T1 values (r = 0.75; p < 0.0001) and was the best noninvasive parameter that correlated with pulmonary capillary wedge pressures (PCWP) (r = 0.54; p < 0.001). Standard echocardiographic parameters of LV diastolic function correlated poorly with both native T1 and PCWP values.

CONCLUSIONS

End-diastolic SW propagation velocities, as measure of myocardial stiffness, showed a good correlation with CMR-defined diffuse myocardial injury and with invasively determined LV filling pressures in patients with HTx. Thus, these findings suggest that SW elastography has the potential to become a valuable noninvasive method for the assessment of diastolic myocardial properties in HTx recipients.

Three-dimensional echocardiography to identify right ventricular dilatation in patients with corrected Fallot anomaly or pulmonary stenosis

Background

3‐Dimensional Echocardiography allows measuring volumes and parameters of myocardial deformation (strain). Myocardial strain has been suggested to be superior to conventional echo parameters in the assessment of right ventricular (RV) function. Myocardial strain can be assessed by cardiac magnetic resonance (CMR) or two‐ and three‐dimensional echocardiography (2D and 3DEcho). We performed a comprehensive assessment of the RV based on 3DEcho and compared the results with those based on CMR and 2DEcho.

Methods

36 patients with corrected heart defects underwent CMR and 3DEcho to assess RV volume, strain and cardio pulmonary exercise testing with peak VO₂ measurement. 2DEcho was used for reference.

Results

There was a moderate correlation between 3DEcho and CMR for measuring RV end‐diastolic and end‐systolic volumes (r = .82 and .72). 3DEcho tended to underestimate the RV volumes, mean difference EDV 8.5 ± 33 ml (CI −2.8; 19.7 ml) and ESV 13.2 ± 29 ml (CI 3.3; 23 ml). According to method‐specific reference values for RVEDV, 34/35 (3DEcho) and 29/36 (CMR) were dilated. Among those dilated according to CMR, all were identified by 3DEcho. The coefficient of correlation between RV atrioventricular plane displacement measured by CMR and tricuspid annular plane systolic excursion measured by 3D and 2DEcho was r = .6 for both. 2DEcho measured lower LV volumes than CMR. LVEF and GLS were similar in 2DEcho, 3DEcho and CMR. Patients with CMR‐determined RV free wall strain ≤ −14% tended to have lower peak VO₂.

Conclusions

Although 3DEcho underestimated RV volumes, it successfully identified all patients with RV dilatation based on method‐specific reference values.

Assessment of long-term cardiac adaptation in adult patients with type II atrial septal defect : A cardiovascular magnetic resonance (CMR) study

OBJECTIVES

In type II atrial septal defect (ASD) patients, the left-to-right (LR) shunt causes adaptation of the heart and circulation. The study objective was to evaluate with cardiovascular magnetic resonance imaging (CMR) the impact of LR shunt on left (LV) and right ventricular (RV) volumes, function, and myocardial strain.

METHODS

Thirty-five patients (42 ± 17 years, 17 male) were compared to a control group (n = 40). Cine imaging was used to calculate ventricular volumes and ejection fraction (EF), global longitudinal (GLS) and circumferential strain (GCS), and longitudinal free wall (FWS) and interventricular septal (IVS) strain. Phase-contrast imaging was used to calculate pulmonary flow to systemic flow ratio (Qp/Qs).

RESULTS

The LR shunt (Qp/Qs 2.2 ± 0.6) resulted in larger RV end-diastolic volume (EDVi) (152 ± 42 vs 82 ± 11 ml/m²), lower LV EDVi (72 ± 16 vs 83 ± 9 ml/m²⁾, and higher RV/LV EDVi ratio (2.2 ± 0.5 vs 1.0 ± 0.1) than controls (all p < 0.001). Functionally, stroke volumes were larger in RV and lower in LV (both p < 0.001) with a strong trend toward lower RV EF in patients (p = 0.08). The LR shunt negatively impacted RV GLS (p = 0.03) but not RV GCS. Longitudinal IVS but not RV FWS were significantly lower in patients, i.e., p < 0.001, of longitudinal IVS. Shunt severity correlated with RV size and stroke volume, right atrial size, and pulmonary trunk diameter (all p < 0.001), but not with functional nor strain parameters.

CONCLUSION

Long-term cardiac adaptation in ASD patients, with RV overfilling and LV underfilling, has a negative impact on systolic RV performance, a phenomenon which likely can be attributed to longitudinal dysfunction of the interventricular septum.

KEY POINTS

• An LR shunt in type II ASD patients causes cardiac remodeling characterized by RV overfilling and conversely underfilling of the left ventricle. • At the long term, there is evidence of systolic dysfunction of the right ventricle in this group of patients. • Septal dysfunction underlies the observed impairment in RV function.

Quantification of left ventricular contribution to stroke work by longitudinal and radial force-length loops

Left ventricular (LV) stroke work (SW) is calculated from the pressure-volume (PV) loop. PV loops do not contain information on longitudinal and radial pumping, leaving their contributions to SW unknown. A conceptual framework is proposed to derive the longitudinal and radial contributions to SW, using ventricular force-length loops reflecting longitudinal and radial pumping. The aim of this study was to develop and validate this framework experimentally and to explore these contributions in healthy controls and heart failure patients. Thirteen swine underwent cardiovascular magnetic resonance (CMR) and LV pressure catheterization at baseline (n = 7) or 1 wk after myocardial infarction (n = 6). CMR and noninvasive PV loop quantification were performed on 26 human controls and 14 patients. Longitudinal and radial forces were calculated as LV pressure multiplied by the myocardial surface areas in the respective directions. Length components were defined as the atrioventricular plane and epicardial displacements, respectively. Contributions to SW were calculated as the area within the respective force-length loop. Summation of longitudinal and radial SW had excellent agreement with PV loop-derived SW (ICC = 0.95, R = 0.96, bias ± SD = −4.5 ± 5.4%) in swine. Longitudinal and radial contributions to SW were ~50/50% in swine and human controls, and 44/56% in patients. Longitudinal pumping required less work than radial to deliver stroke volume in swine (6.8 ± 0.8 vs. 8.7 ± 1.2 mJ/mL, P = 0.0002) and in humans (11 ± 2.1 vs. 17 ± 4.7 mJ/mL, P < 0.0001). In conclusion, longitudinal and radial pumping contribute ~50/50% to SW in swine and human controls and 44/56% in heart failure patients. Longitudinal pumping is more energy efficient than radial pumping in delivering stroke volume.

NEW & NOTEWORTHY A novel method for quantifying the contributions of longitudinal and radial pumping to stroke work using global left ventricular force-length loops was proposed and validated, which can be quantified noninvasively using cardiovascular magnetic resonance and brachial cuff pressure. We found that longitudinal and radial pumping contributes equally to stroke work in controls and 44/56% in heart failure patients, and that the longitudinal pumping is more energy efficient in delivering stroke volume than radial pumping.

Detection of subclinical myocardial dysfunction in cocaine addicts with feature tracking cardiovascular magnetic resonance

BACKGROUND

Cocaine is an addictive, sympathomimetic drug with potentially lethal effects. We have previously shown with cardiovascular magnetic resonance (CMR) the presence of cardiovascular involvement in a significant percentage of consecutive asymptomatic cocaine addicts. CMR with feature-tracking analysis (CMR-FT) allows for the quantification of myocardial deformation which may detect preclinical involvement. Therefore, we aimed to assess the effects of cocaine on the left ventricular myocardium in a group of asymptomatic cocaine users with CMR-FT.

METHODS

In a cohort of asymptomatic cocaine addicts (CA) who had been submitted to CMR at 3 T, we used CMR-FT to measure strain, strain rate and dyssynchrony index in CA with mildly decreased left ventricular ejection fraction (CA-LVEFd) and in CA with preserved ejection fraction (CA-LVEFp). We also measured these parameters in 30 age-matched healthy subjects.

RESULTS

There were no differences according to age. Significant differences were seen in global longitudinal, radial and circumferential strain, in global longitudinal and radial strain rate and in radial and circumferential dyssynchrony index among the groups, with the lowest values in CA-LVEFd and intermediate values in CA-LVEFp. Longitudinal, radial and circumferential strain values were significantly lower in CA-LVEFp with respect to controls.

CONCLUSIONS

CA-LVEFp show decreased systolic strain and strain rate values, with intermediate values between healthy controls and CA-LVEFd. Signs suggestive of dyssynchrony were also detected. In CA, CMR-FT based strain analysis can detect early subclinical myocardial involvement.