Cardiovascular Magnetic Resonance Myocardial Feature Research Articles

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

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

Cardiovascular magnetic resonance myocardial feature tracking for the determination of left atrial strain in hypertensive left ventricular hypertrophy and hypertrophic cardiomyopathy

To measure the left atrial (LA) function in patients with hypertrophic cardiomyopathy (HCM; with [OHCM] and without obstruction [NOHCM]) and hypertension-related left ventricular hypertrophy (H-LVH) using cardiovascular magnetic resonance imaging feature tracking (CMR-FT). Patients who met the criteria for HCM (n=68), H-LVH (n=46), and 30 healthy controls participated. Left atrial strain was analysed using CMR-FT in cine images with two and four chambers. The strain rate and LA strain measurements showed that patients with HCM, and H-LVH had impaired conduit and reservoir functions (versus controls). These capacities were more severely impaired in OHCM than those seen in NOHCM and H-LVH. The LA volume parameters (LAVIpac, LAVImin and LAVImax) from the OHCM group were higher than both the NOHCM and H-LVH groups (all p<0.05). There were differences between the OHCM and H-LVH groups in terms of the parameters for LA reservoir function (εs), booster pump function (SRa), and conduit function (SRe, LA passive EF, εe; p<0.05). The strongest correlations included the associations between LA total EF and εs, εe and LA passive EF, and SRe and LA passive EF. CMR-FT can reliably identify LA dysfunction and deformation in the early stages of HCM and H-LVH.

Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain

Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

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

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

Right Atrial Deformation Using Cardiovascular Magnetic Resonance Myocardial Feature Tracking Compared with Two-Dimensional Speckle Tracking Echocardiography in Healthy Volunteers

Speckle tracking echocardiography (STE), and more recently, cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) provides insight into all phases of atrial function. The aim of our study was to compare all phases of RA strain using CMR-FT and STE and also assess the relationship between RA and LA strain. A total of 61 healthy volunteers with mean age of 45 ± 13 years had adequate tracking for analysis on CMR-FT and 2D-STE. Females had larger RA reservoir strain (39 ± 15% vs. 32 ± 13%, p = 0.046) and conduit strain (26 ± 12% vs. 20 ± 9%, p = 0.03) when compared to males, but was not the case with booster strain (14 ± 7% vs. 12 ± 6%, p = 0.45). In comparison with STE derived strain, the RA reservoir and conduit strain were not significantly different between CMR-FT and the three echocardiography gating methods (p > 0.05 for all). Noticeably, there were no significant differences in strain and strain rate between RA and LA function using CMR-FT (p > 0.05 for all). RA strain and strain rate using CMR-FT had fair and good intra- and inter-observer reproducibility and had superior reproducibility compared to STE derived strain.

Impact of Right Atrial Physiology on Heart Failure and Adverse Events after Myocardial Infarction.

Background: Right ventricular (RV) function is a known predictor of adverse events in heart failure and following acute myocardial infarction (AMI). While right atrial (RA) involvement is well characterized in pulmonary arterial hypertension, its relative contributions to adverse events following AMI especially in patients with heart failure and congestion need further evaluation. Methods: In this cardiovascular magnetic resonance (CMR)-substudy of AIDA STEMI and TATORT NSTEMI, 1235 AMI patients underwent CMR after primary percutaneous coronary intervention (PCI) in 15 centers across Germany (n = 795 with ST-elevation myocardial infarction and 440 with non-ST-elevation MI). Right atrial (RA) performance was evaluated using CMR myocardial feature tracking (CMR-FT) for the assessment of RA reservoir (total strain εs), conduit (passive strain εe), booster pump function (active strain εa), and associated strain rates (SR) in a blinded core-laboratory. The primary endpoint was the occurrence of major adverse cardiac events (MACE) 12 months post AMI. Results: RA reservoir (εs p = 0.061, SRs p = 0.049) and conduit functions (εe p = 0.006, SRe p = 0.030) were impaired in patients with MACE as opposed to RA booster pump (εa p = 0.579, SRa p = 0.118) and RA volume index (p = 0.866). RA conduit function was associated with the clinical onset of heart failure and MACE independently of RV systolic function and atrial fibrillation (AF) (multivariable analysis hazard ratio 0.95, 95% confidence interval 0.92 to 0.99, p = 0.009), while RV systolic function and AF were not independent prognosticators. Furthermore, RA conduit strain identified low- and high-risk groups within patients with reduced RV systolic function (p = 0.019 on log rank testing). Conclusions: RA impairment is a distinct feature and independent risk factor in patients following AMI and can be easily assessed using CMR-FT-derived quantification of RA strain.

Cardiac magnetic resonance feature tracking for quantifying right ventricular deformation in type 2 diabetes mellitus patients

To determine the feasibility of deformation analysis in the right ventricle (RV) using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) in type 2 diabetes mellitus (T2DM) patients. We enrolled 104 T2DM patients, including 14 with impaired right ventricular ejection fraction (RVEF) and 90 with preserved RVEF, and 26 healthy controls in this prospective study. CMR was used to determine RV feature-tracking parameters. RV strain parameters were compared among the controls, patients with preserved and reduced RVEF. Binary logistic regression was used to predict RV dysfunction. Receiver operating characteristic analysis was used to assess the diagnostic accuracy. The agreement was tested by Bland–Altman analysis. Compared with controls, longitudinal and circumferential global peak strain (PS) and PS at mid-ventricular, apical slices were significantly decreased in T2DM patients with or without reduced RVEF (p < 0.05). Within the T2DM patients, the global longitudinal PS (GLPS) and the longitudinal PS at mid-ventricular segments were significantly reduced in the reduced RVEF group than in preserved RVEF groups (p < 0.05). GLPS was an independent predictor of RV dysfunction (odds ratio: 1.246, 95% CI: 1.037–1.496; p = 0.019). The GLPS demonstrated greater diagnostic accuracy (area under curve: 0.716) to predict RV dysfunction. On Bland-Altman analysis, global circumferential PS and GLPS had the best intra- and inter-observer agreement, respectively. In T2DM patients, CMR-FT could quantify RV deformation and identify subclinical RV dysfunction in those with normal RVEF. Further, RV strain parameters are potential predictors for RV dysfunction in T2DM patients.

Prognostic value of left atrial function by cardiovascular magnetic resonance feature tracking in hypertrophic cardiomyopathy.

Left atrium (LA) size has an important role in determining prognosis and risk stratification in hypertrophic cardiomyopathy (HCM). Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a novel technique for the quantification of LA function. Our aim was first to evaluate LA function by CMR-FT and volumetric analysis in patients with HCM; and secondly we sought to determine the association of LA-longitudinal strain (LA-LS) with major cardiovascular outcomes, particularly all cause mortality and heart failure. 75 patients with HCM and 75 control subjects underwent a conventional CMR study including assessment of LA function by CMR-FT (LA-LS) and volumetric analysis. A primary endpoint of all-cause mortality and secondary combined endpoint of hospital admission related to heart failure, lethal ventricular arrhythmias or cardiovascular death were defined. Compared to controls, LA-LS and all volumetric indices of LA function were significantly impaired in HCM even in patients with normal LA volume and normal LV filling pressures. LA-LS showed moderate-high correlation with LA-emptying fraction (total, active and passive LA-EF, r = 0.68, r = 0.67, r = 0.31, p < 0.001 for all) and with parameters of diastolic function (E/é, r = 0.4, p < 0.001). The age, minimum LA volume and % of LGE were independent predictors of LA-LS (p < 0.01 for all). During a mean follow-up of 3.3 ± 1.2years LA-LS was associated with the primary (HR: 0.85 (0.73-0.98), p = 0.02) and the secondary end-point (HR: 0.88 (0.82-0.96), p = 0.003). LA-LS by CMR-FT provides accurate measurements of LA function in HCM patients. LA-LS may become a novel potential predictor of poor cardiac outcomes, particularly cardiovascular mortality and HF.

Clinical applications of feature-tracking cardiac magnetic resonance imaging.

Cardiovascular diseases represent the leading cause of mortality and morbidity in the western world. Assessment of cardiac function is pivotal for early diagnosis of primitive myocardial disorders, identification of cardiac involvement in systemic diseases, detection of drug-related cardiac toxicity as well as risk stratification and monitor of treatment effects in patients with heart failure of various etiology. Determination of ejection fraction with different imaging modalities currently represents the gold standard for evaluation of cardiac function. However, in the last few years, cardiovascular magnetic resonance feature tracking techniques has emerged as a more accurate tool for quantitative evaluation of cardiovascular function with several parameters including strain, strain-rate, torsion and mechanical dispersion. This imaging modality allows precise quantification of ventricular and atrial mechanics by directly evaluating myocardial fiber deformation. The purpose of this article is to review the basic principles, current clinical applications and future perspectives of cardiovascular magnetic resonance myocardial feature tracking, highlighting its prognostic implications.

Left ventricular myocardial deformation in Takotsubo syndrome: a cardiovascular magnetic resonance myocardial feature tracking study.

This study assessed the applicability and prognostic value of cardiovascular magnetic resonance (CMR) left ventricular deformation analysis in Takotsubo syndrome (TTS). CMR-feature tracking was performed blinded in a core laboratory to determine circumferential (CS), radial (RS) and longitudinal strain (LS) in 141 TTS patients participating in this cohort study. A subgroup of consecutive TTS patients (n = 20) was compared with age- and sex-matched controls with anterior ST-segment elevation myocardial infarction (STEMI) and non-STEMI as well as healthy subjects. Median global CS, RS and LS were -19%, 19% and -12%, respectively. Apical ballooning was associated with significantly lower global CS (p < 0.01) and LS (p < 0.01) compared with midventricular and basal ballooning. Global RS was lowest in patients with basal ballooning (p < 0.01). Segmental analysis resulted in a reliable discrimination of different ballooning patterns using CS and LS. Strain values were significantly lower in TTS compared with non-STEMI patients and healthy subjects, whereas STEMI patients showed similar values. While global CS and RS were not associated with long-term mortality, global LS (cutoff -14.75%) was identified as a potential parameter for long-term risk stratification (mortality rate 17.9% versus 2.5%; p = 0.02). The transient contraction abnormalities in TTS can be quantitatively assessed with CMR-feature tracking. GLS is a potential determinant of outcome in TTS, which, however, requires further validation. • Cardiovascular magnetic resonance myocardial feature tracking enables accurate assessment of regional and global left ventricular dysfunction in Takotsubo syndrome (TTS). • Global strain in TTS is similar to patients with anterior STEMI and lower compared with non-STEMI and healthy subjects. • Global longitudinal strain is a potential tool for risk prediction in TTS patients.

Quantification of Biventricular Strain and Assessment of Ventricular Interaction in Pulmonary Arterial Hypertension Using Exercise Cardiovascular Magnetic Resonance Imaging and Myocardial Feature Tracking

Quantification of Biventricular Strain and Assessment of Ventricular Interaction in Pulmonary Arterial Hypertension Using Exercise Cardiovascular Magnetic Resonance Imaging and Myocardial Feature Tracking

Prognostic implications of global myocardial mechanics in hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking. Relations to left ventricular hypertrophy and fibrosis

BackgroundInterstitial fibrosis, myocardial fiber disarray and non-uniform shortening are common histological features of hypertrophic cardiomyopathy (HCM). The degree of LV hypertrophy and fibrosis are postulated to contribute to the impairment of myocardial shortening. Cardiovascular magnetic resonance myocardial (CMR) feature tracking (CMR-FT) has emerged as a robust method that provides quantitative measurements of myocardial deformation. Our aim was first to evaluate LV strain parameters in HCM by CMR-FT and their dependence on both functional parameters and late gadolinium enhancement (LGE); and secondly we sought to determine their association with major cardiovascular outcomes. Methods and results74 patients with HCM and 75 controls subjects underwent a CMR study including LGE imaging. Global peak longitudinal, circumferential and radial systolic strain values (GLS, GCS, GRS) were measured by CMR-FT. A primary endpoint of all-cause mortality and secondary combined endpoint of hospital admission related to heart failure, lethal ventricular arrhythmias or cardiovascular death were defined. Patients with HCM showed attenuation of all LV strain values (p<0.001). Multivariate analysis showed that both LV hypertrophy and %of LGE were independent predictors of attenuated LV strains. All systolic LV strain parameters were impaired in patients with primary and secondary endpoints (follow up time: 25.6±9.9months, p<0.05 and p<0.01 respectively). Abnormal GLS, GCS and GRS were significantly associated with primary and secondary endpoints. ConclusionBoth LV hypertrophy and fibrosis contribute to the impairment of LV myocardial mechanics in HCM. In this population, reduced LV strain is associated with poor cardiac outcomes, particularly cardiovascular mortality and HF.

Cardiovascular magnetic resonance myocardial feature tracking using a non-rigid, elastic image registration algorithm: assessment of variability in a real-life clinical setting

BackgroundCardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a promising technique for quantification of myocardial strain from steady-state free precession (SSFP) cine images. We sought to determine the variability of CMR-FT using a non-rigid elastic registration algorithm recently available in a commercial software package (Segment, Medviso) in a real-life clinical setting.MethodsFirstly, we studied the variability in a healthy volunteer who underwent 10 CMR studies over five consecutive days. Secondly, 10 patients were selected from our CMR database yielding normal findings (normal group). Finally, we prospectively studied 10 patients with known or suspected myocardial pathology referred for further investigation to CMR (patient group). In the patient group a second study was performed respecting an interval of 30 min between studies. All studies were manually segmented at the end-diastolic phase by three observers. In all subjects left ventricular (LV) circumferential and radial strain were calculated in the short-axis direction (EccSAX and ErrSAX, respectively) and longitudinal strain in the long-axis direction (EllLAX). The level of CMR experience of the observers was 2 weeks, 6 months and >20 years.ResultsMean contouring time was 7 ± 1 min, mean FT calculation time 13 ± 2 min. Intra- and inter-observer variability was good to excellent with an coefficient of reproducibility (CR) ranging 1.6% to 11.5%, and 1.7% to 16.0%, respectively and an intraclass correlation coefficient (ICC) ranging 0.89 to 1.00 and 0.74 to 0.99, respectively. Variability considerably increased in the test-retest setting with a CR ranging 4.2% to 29.1% and an ICC ranging 0.66 to 0.95 in the patient group. Variability was not influenced by level of expertise of the observers. Neither did the presence of myocardial pathology at CMR negatively impact variability. However, compared to global myocardial strain, segmental myocardial strain variability increased with a factor 2–3, in particular for the basal and apical short-axis slices.ConclusionsCMR-FT using non-rigid, elastic registration is a reproducible approach for strain analysis in patients routinely scheduled for CMR, and is not influenced by the level of training. However, further improvement is needed to reliably depict small variations in segmental myocardial strain.

Cardiovascular Magnetic Resonance Myocardial Feature Tracking: Concepts and Clinical Applications.

Heart failure-induced cardiovascular morbidity and mortality constitute a major health problem worldwide and result from diverse pathogeneses, including coronary artery disease, nonischemic cardiomyopathies, and arrhythmias. Assessment of cardiovascular performance is important for early diagnosis and accurate management of patients at risk of heart failure. During the past decade, cardiovascular magnetic resonance myocardial feature tracking has emerged as a useful tool for the quantitative evaluation of cardiovascular function. The method allows quantification of biatrial and biventricular mechanics from measures of deformation: strain, torsion, and dyssynchrony. The purpose of this article is to review the basic principles, clinical applications, accuracy, and reproducibility of cardiovascular magnetic resonance myocardial feature tracking, highlighting the prognostic implications. It will also provide an outlook on how this field might evolve in the future.

Quantification of left atrial strain and strain rate using cardiovascular magnetic resonance myocardial feature tracking

Background Cardiovascular Magnetic Resonance myocardial feature tracking (CMR-FT) is a quantitative technique tracking tissue voxel motion on standard steady-state free precession (SSFP) cine images to assess ventricular myocardial deformation. The importance of left atrial (LA) deformation assessment is increasingly recognized and can be assessed with echocardiographic speckle tracking. However atrial deformation quantification has never previously been demonstrated with CMR. We sought to determine the feasibility and reproducibility of CMR-FT for quantitative LA strain and strain rate (SR) analysis.

A comparison of cardiac motion analysis software packages: application to left ventricular deformation analysis in hypertensive patients

Background Although myocardial function is clinically assessed with global measurements (ventricular volumes, ejection fraction), recent research has shown that regional measurements, such as wall-thickening, strain, and torsion, could provide earlier sub-clinical markers to examine left ventricular (LV) dysfunction and myocardial diseases. Cardiovascular Magnetic Resonance myocardial feature tracking (CMR-FT) technique is used to post-process cine CMR images to provide a quantitative assessment of LV motion deformation parameters. It derives myocardial motion deformation from image features such as myocardium-blood cavity boundary and pixel intensities, and relies only on standard cine images to extract motion deformation. The main objective of this study is to compare two current feature tracking software packages in hypertensive patients. Methods 29 hypertensive subjects were prospectively recruited from a tertiary hypertension clinic and enrolled to undergo CMR examinations. All images were acquired using a 1.5T scanner (Siemens Medical Imaging, Germany), and a cardiac surface coil. LV function was assessed with cine acquisitions in the following planes: 2-chamber, 4-chamber and short-axis slices (basal, mid and apical levels). LV deformation was analysed using: 2D Cardiac Performance Analysis, MR (TomTec Imaging Systems, Munich, Germany) and CVI42 (Circle Cardiovascular Imaging Inc. Calgary, Canada). Endocardial and epicardial LV contours were drawn manually at the end diastolic phase in order to achieve best tracking results; the software packages then allow semi-automated analysis to provide quantitative measurement of global and regional deformation parameters. Results Results of circumferential, radial, and longitudinal strains are given in table 1. Statistical analysis was performed using the student’s paired t-test for dependent sample in order to assess the difference between the two software packages.All radial strain mean values obtained with CVI42 were higher than with Tomtec and the difference was statistically significant for all short-axis circumferential strains. This was also the case for shortaxis apical and 4-chamber radial strains. In total five parameters (short-axis apical and 4-chamber radial strains, all 3 short-axis slices circumferential strains) were statistically different and 5 were not. Conclusions From our results, there is a trend in circumferential strain in short-axis (apical, mid, and basal) where there is a significant difference in the values obtained by the two software packages, whereas radial and longitudinal strain values showed no clear trend. Therefore, there is a clear need for a gold standard validation to assess the accuracy of cardiac motion analysis software packages.

Quantitative assessment of myocardial mechanics in patients with cardiac amyloid using cardiovascular magnetic resonance myocardial feature tracking

Background Cardiovascular magnetic resonance (CMR) feature-tracking (FT) allows the quantitative assessment of complex ventricular mechanics such as strain, twist and untwist. LV twist results from the dynamic interplay between systolic clockwise rotation of the base and a counterclockwise rotation of the apex followed by untwisting during diastole. We sought to determine whether strain, myocardial twist and untwist rates could be measured by CMR-FT and hypothesized that twist and untwist rates would be reduced in patients with amyloid disease as a consequence of systolic and diastolic dysfunction.

Left atrial physiology and pathophysiology: Role of deformation imaging.

The left atrium (LA) acts as a modulator of left ventricular (LV) filling. Although there is considerable evidence to support the use of LA maximum and minimum volumes for disease prediction, theoretical considerations and a growing body of literature suggest to focus on the quantification of the three basic LA functions: (1) Reservoir function: collection of pulmonary venous return during LV systole; (2) Conduit function: passage of blood to the left ventricle during early LV diastole; and (3) Contractile booster pump function (augmentation of ventricular filling during late LV diastole. Tremendous advances in our ability to non-invasively characterize all three elements of atrial function include speckle tracking echocardiography (STE), and more recently cardiovascular magnetic resonance myocardial feature tracking (CMR-FT). Corresponding imaging biomarkers are increasingly recognized to have incremental roles in determining prognosis and risk stratification in cardiac dysfunction of different origins. The current editorial introduces the role of STE and CMR-FT for the functional assessment of LA deformation as determined by strain and strain rate imaging and provides an outlook of how this exciting field may develop in the future.

Quantification of intra and inter-ventricular dyssynchrony in Ebstein's anomaly using cardiovascular magnetic resonance myocardial feature tracking

Background Ebstein’s anomaly consists of varying degrees of tricuspid dysplasia and displacement into the right ventricular (RV) cavity, along with changes in ventricular function predominantly affecting the RV. Measuring alterations in contraction pattern and dyssynchrony may provide insights into ventricular performance in this disease. We sought to quantify right and left ventricular (RV and LV) deformation and dyssynchrony in a cohort of patients with Ebstein’s anomaly in comparison with normal controls using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT).

Cardiovascular magnetic resonance myocardial feature tracking for the measurement of myocardial twist and untwist at rest and during dobutamine stress in healthy volunteers

Background CMR feature tracking (CMR-FT) is a method of assessing strain from routinely acquired steady- state free precession (SSFP) cine images similar to echocardiographic speckle tracking. However, its application to determine myocardial twist and untwist has never previously been explored. We sought to determine the feasibility of measuring twist and untwist from routine cine images in healthy volunteers at rest and during inotropic stimulation.