Cardiac Magnetic Resonance Feature Tracking Research Articles

Abstract 11287: Structural Remodeling Impairs Left Atrial Function in Patients With Atrial Fibrillation: A Cardiac MRI Study

Introduction: Left atrial (LA) fibrosis and enlargement are hallmarks of structural remodeling that contribute to atrial fibrillation (AF) pathophysiology. Cardiac magnetic resonance (CMR) feature tracking has higher spatial resolution and better ability to define the endocardial border, overcoming the challenges related to speckle tracking echocardiography particularly the anatomic location of LA and thinness of the atrial wall. We aimed to assess the association of LA fibrosis and volume with LA function and compliance using CMR imaging. Methods: We analyzed CMR images of AF patients prior to their first catheter ablation. LA fibrosis was assessed using Late Gadolinium Enhancement CMR (Panel A). Feature tracking was applied to assess global longitudinal reservoir strain (GLRS) (Panel B). LA emptying fraction, LA volume index and LA sphericity index were measured using the Cine sequences. All CMR images were acquired in sinus rhythm. Results: 101 patients were included in the study (61% male, mean age 62 years). Median LA volume index was 45.16 mL/m 2 [36.64, 56.5], LA fibrosis percentage was 15.5% [9.6, 19], LA sphericity index was 54.09% [46.44, 64.58] and GLRS was 17.4 [14.95, 20.1]. A Pearson correlation analysis showed that increased LA fibrosis was negatively associated with both GLRS and LA emptying fraction (R=-0.35, p<0.001 and R=-0.27, p=0.007 respectively). LA volume index was also negatively correlated with GLRS and LA emptying fraction (R=-0.37, p<0.001 and R=-0.54, p<0.001, respectively) (Panel C). Neither LA fibrosis nor LA volume index was associated with LA sphericity index (p=0.55 and p=0.4 respectively). Conclusion: LA structural remodeling including increased fibrosis and LA volume is associated with a worsening LA function by strain imaging on CMR. Fibrotic remodeling may lead to blood stasis and play a role in the pathophysiology of thromboembolic stroke associated with AF.

Direct comparison of echocardiography speckle tracking and cardiac magnetic resonance feature tracking for quantification of right ventricular strain: a prospective intermodality study in functional mitral regurgitation

BackgroundFunctional mitral regurgitation (FMR) is a known risk factor for right ventricular dysfunction (RVDYS). RV global longitudinal strain (GLS) is an emerging index of RV function; however, the magnitude of agreement between RV GLS by echocardiography (echo) and cardiac magnetic resonance (CMR) and the relative utility of each modality for both the diagnosis of RVDYS and prognostication of all-cause mortality and heart failure hospitalization remain unknown.Results32% of patients had RVDYS (EF < 50%) on CMR, among whom there was more advanced NYHA class and lower LV and RV ejection fraction (all p < 0.05). RV GLS was impaired in patients with RVDYS whether quantified via STE or FT-CMR, with strong correlation between modalities (r = 0.81). Both STE and FT-CMR derived GLS yielded excellent detection of RVDYS (AUC 0.94 for both), paralleling similar performance for free wall strain by both modalities (FT-CMR AUC 0.94, STE AUC 0.92) with lower accuracy demonstrated by STE derived septal strain (STE AUC 0.78 and FT-CMR AUC 0.92). RV S’ and TAPSE showed lower diagnostic accuracy (RV S’ AUC 0.77 and TAPSE AUC 0.81). During median follow up of 51 months (IQR 42, 60 months), all-cause mortality or HF hospitalization occurred in 25% (n = 25). Both STE and FT-CMR derived RV GLS stratified risk for adverse prognosis (STE p = 0.007, FT-CMR p = 0.005) whereas conventional RV indices, TAPSE and RV S’, did not (TAPSE p = 0.30, S’ p = 0.69).ConclusionRV GLS is a robust marker of RVDYS irrespective of modality which provides incremental diagnostic value and improves risk stratification for event free survival beyond conventional RV indices.

Left ventricular strain patterns and their relationships with cardiac biomarkers in hypertrophic cardiomyopathy patients with preserved left ventricular ejection fraction.

AimsThis study aims to assess left ventricular (LV) function in hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction (LVEF) by LV strain patterns based on cardiac magnetic resonance feature tracking (CMR-FT) and to explore the relationships between LV strain patterns and cardiac biomarkers in these patients, such as cardiac troponin (cTnT) and N-terminal prohormone of the brain natriuretic peptide (NT-proBNP).MethodsA total of 64 HCM patients with preserved LVEF and 33 healthy people were included in this study. All subjects underwent contrast-enhanced CMR, and all patients took blood tests for cTnT and NT-proBNP during hospitalization.ResultsDespite the absence of a significant difference in LVEF between HCM patients and healthy controls, almost all global and segmental strains in radial, circumferential, and longitudinal directions in the HCM group deteriorated significantly as compared to controls (p < 0.05). Moreover, some global and segmental strains correlated significantly with NT-proBNP and cTnT in HCM patients, and the best correlations were global radial strain (GRS) (r = −0.553, p < 0.001) and mid-ventricular radial strain (MRS) (r = −0.582, p < 0.001), respectively, with a moderate correlation. The receiver operating characteristic (ROC) results showed that among the LV deformation parameters, GRS [area under the curve (AUC), 0.76; sensitivity, 0.49; specificity, 1.00], MRS (AUC, 0.81; sensitivity, 0.77; specificity, 0.79) demonstrated greater diagnostic accuracy to predict elevated NT-proBNP, and abnormal cTnT, respectively. Their cut-off values were 21.17 and 20.94%, respectively. Finally, all global strains demonstrated moderate, good, and excellent intra- and inter-observer reproducibility.ConclusionLV strain patterns can be used to assess the subclinical cardiac function of HCM patients on the merit of being more sensitive than LVEF. In addition, LV strain patterns can detect serious HCM patients and may be helpful to non-invasively predict elevated NT-proBNP and cTnT.

Right ventricular function and outcome in patients undergoing transcatheter mitral valve repair

Abstract Objectives This study sought to assess the impact of right ventricular dysfunction (RVD) on event-free survival after transcatheter mitral valve repair (TMVR) for severe mitral regurgitation. Background The prognostic value of left and RV global longitudinal strain (LV- and RV-GLS) on cardiovascular magnetic resonance feature tracking (CMR-FT) in patients undergoing TMVR is unknown. Methods Consecutive TMVR patients underwent pre-procedural and follow-up CMR-FT analysis. Kaplan-Meier estimates and multivariable Cox-regression analyses were performed, using a composite endpoint of heart failure hospitalization (HFH) and death. Results 62 patients (78.3±7.0y/o, 45% female, EuroSCORE-II: 9.6±7.1%) underwent CMR-FT prior to TMVR, 24% had concomitant tricuspid edge-to-edge repair (TTVR). On presentation, 23 (37%) patients suffered RVD, defined as RV-GLS &amp;gt;−20% on CMR-FT. RVD was associated with reduced LV and RV ejection fraction (LVEF: 39.2 vs. 48.7%, p=0.008, RVEF: 35.1 vs. 46.7%, p&amp;lt;0.001), as well as impaired LV-GLS (−14.0 vs. −19.5%, p=0.012). Eighteen events (12 deaths, 6 HFH) occurred during follow-up (11.4±9.1 months). On multivariable Cox-regression adjusted for baseline, procedural, imaging, and biomarker data, RV but not LV-GLS was significantly associated with outcome (adj.HR 2.50, 95% CI: 1.29–4.86, p=0.007 and 1.46, 95% CI: 0.50–4.28, p=0.491, respectively). Among various definitions of RVD on echocardiography and CMR, only RV-GLS on CMR-FT was significantly associated with outcome (RV-GLS &amp;gt;−20%: adj.HR 7.53, 95% CI: 2.07–27.42, p=0.002), but not RVEF on CMR or echo-indices of RV function (Central Illustration). Follow-up CMR-FT was performed in 21 (34%) patients and RV-GLS significantly improved after TMVR (−20.6 to −25.2%, p=0.016), irrespective of additional TTVR. Conclusions RV-GLS, as determined on CMR-FT, rather than LV-GLS or RVEF, is an independent predictor of outcome in patients undergoing TMVR. Funding Acknowledgement Type of funding sources: None.

Cardiac magnetic resonance feature-tracking analysis of left atrial volumes and function in standard vs left-atrial focused images

Abstract Background Left atrial (LA) volume and function have shown prognostic value in several cardiac conditions. Routine cardiac magnetic resonance (CMR) evaluation of the LA is obtained from standard 2- and 4-chamber long-axis cine images focused on the left ventricle. Previous echocardiographic data showed that LA-focused apical views provide a more accurate estimation of LA maximum volume, as compared to standard apical images. CMR LA-focused imaging could improve the accuracy of LA morpho-functional analysis. CMR feature-tracking (CMR-FT) analysis is emerging as a feasible semi-automatic tool for the evaluation of LA volumes and function. Purpose To investigate the potential of LA-focused CMR cine images using LA CMR-FT analysis. Methods 100 consecutive patients clinically referred to CMR were included in this prospective, observational, multicenter study. LA volumes (LAVmax, LAVmin), emptying fraction (EF), atrial strain reservoir (ɛs), conduit (ɛe), booster (ɛa) and strain rate reservoir (SRɛs) were calculated by CMR-FT analysis on both standard and LA-focused 2- and 4-chamber long-axis cine images. Manual segmentation of a short-axis cine stack covering the LA was used as the reference method (RefMeth) for LA volumes and EF. Results In comparison to the RefMeth, the standard acquisitions underestimated LA volumes (LAVmax: bias = −8ml, LOA = +20, −35ml; LAVmin: bias = −6 ml, LOA = +15, −27ml) and slightly overestimated EF (bias = +3%, LOA = +17, −11%). Conversely, LA-focused images provided a more accurate estimation (LAV max bias = −1ml, LOA = +11, −9ml; LAV min bias = −2ml, LOA = +12, −7ml) and EF (bias = −2%, LOA = +9, −12%). All three LA strain (εs: bias 7%, LOA = 25, −11%; εe: bias 4%, LOA = 15, −8%; εa: bias 3%, LOA = 14, −8%) and SRεs (bias 0.2 s–1, LOA = 1.13, −0.7 s–1) were significantly higher in standard vs LA-focused images (all p&amp;lt;0.001). Conclusions Assessment of LA volumes using CMR-FT applied to dedicated LA-focused long-axis cine images is more accurate than the use of standard acquisitions. LA strain and SRɛs obtained from LA-focused images are significantly lower than those obtained from standard LA acquisitions, possibly due to the inclusion in LA-focused images of LA posterior wall, where pulmonary veins convey and atrial deformation is blunted. Funding Acknowledgement Type of funding sources: None.

Inter-field strength agreement of cardiovascular magnetic resonance cine-derived strain and strain rate measures: a randomised study

Abstract Background Left ventricular (LV) strain and strain rate measurements can be derived from routinely acquired cardiovascular magnetic resonance (CMR) cine images by feature tracking techniques. However, the inter-field strength agreement of strain measurements derived from these techniques is not known. We hypothesised that there would be excellent inter-field strength agreement (between 1.5 and 3 Tesla [T]) for the measurement of global strain and strain rate derived from cine imaging. Methods Prospective, randomised cross-over observational study. Healthy volunteers each underwent CMR scans at 1.5T and 3T within 30 minutes on the same day in a randomised order. Retrospectively ECG gated, short and long-axis balanced steady state free precession cine images were obtained using standardised acquisition parameters at both field strengths. Two software packages were used to derive LV global longitudinal, circumferential and long and short axis radial systolic strain, peak systolic, early diastolic and late diastolic strain rates. All strain values are expressed as positive numbers. Results Twenty-two subjects (mean age 36±12 years; 45% male) were studied. No differences in heart rate and blood pressure measurements during scanning were observed between field strengths. The abstract figure shows an example of strain analysis and Bland-Altman plots for global longitudinal and circumferential strain. Minimal bias was seen in all strain and strain rate measurements between field strengths using the first software package. Strain and strain rate values derived from long axis images (longitudinal and long axis radial) showed poor to fair agreement (intraclass correlation co-efficient (ICC) range 0.39–0.71), whereas measures derived from short axis images (circumferential and short axis radial) showed good to excellent agreement between field strengths (ICC range 0.78–0.91). Similar results were observed with the second software package, though the differences in agreement between long and short axis derived measures were less pronounced. Conclusion Longitudinal strain and strain rate measures derived from CMR feature tracking have poor inter-field strength agreement between 1.5T and 3T. By contrast, agreement of circumferential and short axis radial strain and strain rate measurements at 1.5T and 3T is good. These results need to be considered when assessing strain at different field strengths. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): United Kingdom National Institute for Health Research

Myocardial deformation in athletes measured with feature tracking cardiovascular magnetic resonance

Abstract Background Morphological changes of the heart associated with exercise are well studied. However, changes in myocardial mechanics of athlete's heart are less understood. The aim of this study was to analyze myocardial deformation parameters in athletes and controls, using feature tracking cardiac magnetic resonance (FT-CMR). Methods In a cohort of 73 athletes who had been submitted to CMR at 1.5T and 3 T (mean age 31±12 years, 69% males), we used CMR-FT to measure longitudinal, circumferential and radial strain and strain rates of both ventricles. Left ventricle (LV) longitudinal, circumferential and radial dyssynchrony index (L-SDI, C-SDI and R-CDI, respectively) was calculated as the standard deviation of the calculated time to peak strain percentages of the cardiac cycle with segmental strain analysis. We also measured these parameters in 73 age-matched healthy subjects. Results In comparison to the control subjects, athletes revealed lower left and right ventricle global longitudinal strain (−14.24% vs. −13.31%, p=0.03, and −18.12% vs. −15.95% p=0.01, respectively) and right ventricular (RV) global radial strain (19.28 vs 15.74, p&amp;lt;0.05) – Figure 1. There were no significant differences in LV global radial and circumferential strain. LV longitudinal, radial and circumferential systolic strain rate were also lower in athletes compared to controls (−0.69 s–1 vs. −0.78 s–1, p=0.04; 1.35 s–1 vs. 1.50 s–1, p=0.03: −0.92 s–1 vs −0.98 s–1, p=0.05, respectively). Regarding LV dyssynchrony index, we found no significant difference for L-SDI (10.76% vs. 10.72%, p=0.956), but athletes group showed lower C-SDI and R-SDI values (5.99% vs 4.84%, p=0.006, and 5.53% vs 4.47%, p=0.002). Conclusion Our study revealed attenuation of biventricular strain values and lower circumferential and radial LV dyssynchrony indexes in athletes, compared with healthy controls. We hypothesize that these differences may be related with exercise physiologic cardiac adaptations. Funding Acknowledgement Type of funding sources: None.

Relevance of subclinical right ventricular dysfunction measured by feature-tracking cardiac magnetic resonance in non-ischemic dilated cardiomyopathy

Abstract Background Right ventricular (RV) dysfunction is associated with worse prognosis in non-ischemic dilated cardiomyopathy (NIDCM). Cardiac magnetic resonance (CMR) is considered the gold standard for RV evaluation. However, scarce data is available with the new feature tracking (FT) technique, which allows strain evaluation from conventional cine sequences. Purpose Our aim is to analyze the prognostic relevance of RV myocardial deformation measured by FT-CMR in NIDCM. Methods Consecutive patients with NIDCM diagnosis and CMR at diagnosis were retrospectively included. Global longitudinal strain of RV free wall (GLS-RVFW) and fractional area change (FAC) were obtained from standard CMR cine sequences with a dedicated FT software. Their association with a composite endpoint (heart failure admission, implantable cardioverter defibrillator in secondary prevention, and death) was evaluated using a logistic regression model. Results FT derived strain was obtained in 98 patients (68±13 years, 71.4% males) with NIDCM, mostly idiopathic (75.5%). Although our cohort showed a severely impaired left ventricular systolic function (LVEF = 29.5±9.6%, 47% with LVEF ≥30%) the RV function was relatively preserved on average (RVEF 52.2±14.6%, 72% with RVEF ≥45%). During a 3.2 [2.2–4] years follow-up 26.5% presented at least one admission for heart failure (HF), 5.1% received an implantable cardioverter defibrillator in secondary prevention, and 8% died. There was no association of RV-FT parameters with prognosis considering the entire study population. However, in patients with LVEF ≥30%, admissions for HF were associated with worse values of GLS-RVFW (−21.6±6.6% vs −31.3±10%; p=0.006) and FAC (32.8±15.8% vs 47.5±13.9%; p&amp;lt;0.001). Similar differences were observed when only patients with RVEF &amp;gt;45% were considered. An GLS-RVFW cut-off point of −19.5% and FAC of 36.5% showed good prognostic performance. Decreased GLS-RVFW or FAC represented an independent predictor for the composite endpoint in patients with LVEF ≥30%. Conclusions In our series of NIDCM decreased values of GLS-RVFW or FAC were able to predict major events independently of RVEF in the subgroup of patients without severe LV dysfunction. Therefore, RV deformation parameters by FT may be early markers of poor prognosis in NIDCM. Funding Acknowledgement Type of funding sources: None.

Right atrial function in HFpEF in sinus rhythm vs. atrial fibrillation

Abstract Aims We sought to study the prognostic impact of right atrial (RA) size and function in patients with heart failure with preserved ejection fraction (HFpEF) in sinus rhythm (SR) vs. atrial fibrillation (AF). Methods and results Consecutive HFpEF patients were enrolled and indexed RA volumes and emptying fractions (RA-EF) were assessed by cardiac magnetic resonance imaging (CMR). For patients in SR during CMR feature tracking of the RA wall was performed (Figure 1). In addition, all patients underwent right and left heart catheterization, 6 min walk test, and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) evaluation. We prospectively followed patients and used Cox regression models to determine the association of RA size and function with a composite endpoint of heart failure hospitalization and cardiovascular death. A total of 188 patients (71% female patients, 70±8 years old) were included of whom 96 (51%) were in SR. Eighty-five patients reached the combined endpoint during a follow-up of 72 (33–101) months. After multivariate cox regression analysis adjusted for age, NT-proBNP level, right ventricular ejection fraction and HF functional class, impaired RA strain (Figure 1A) (HR 0.959; 95% CI [0.924–0.996], P=0.024), RA conduit strain (Figure 1A) (HR 0.944; 95% CI [0.898–0.993], P=0.027) and RA conduit strain rate (Figure 1B) (HR 0.990; 95% CI [0.883–0.998], P=0.013) were significantly associated with adverse outcome for patients in SR (Table 1). In persistent AF, no RA imaging parameter was related to outcome after multivariate regression analysis. Conclusions In HFpEF patients in SR, CMR parameters of impaired RA conduit function show the best association with adverse cardiovascular outcome. In persistent AF, RA parameters lose their prognostic ability. Funding Acknowledgement Type of funding sources: None.

Early cardiac involvement detected by cardiac magnetic resonance feature tracking in idiopathic inflammatory myopathy with preserved ejection fraction.

Cardiac involvement is common in idiopathic inflammatory myopathy (IIM) but often subclinical. Cardiac magnetic resonance (CMR) is a promising tool in detecting cardiac involvement in patients with IIM. The aim of this study was to assess cardiac involvement in IIM patients by CMR feature tracking (CMR-FT). Thirty-seven IIM patients and 25 controls were enrolled in this retrospective study. The left ventricular (LV) functional parameters such as volume and ejection fraction were measured. Global and regional LV peak strain (PS) in radial, circumferential and longitudinal directions were derived from cine images. Left atrial (LA) volume, longitudinal strain and strain rate (SR) parameters and LA reservoir function, conduit function and booster pump function were assessed, respectively. IIM patients with preserved LVEF showed significantly reduced global and regional LV PS in longitudinal direction (all p < 0.05). Compared with controls, LA reservoir and conduit function were significantly impaired in IIM patients (all p < 0.05). The global LV longitudinal PS, LAVpre-ac and SRe were independent predictors of IIM. By Pearson's correlation analysis, the LV global radial, circumferential and longitudinal PS were all correlated to LVEF in IIM patients (r = 0.526, p < 0.001 vs. r = -0.514, p < 0.001 vs. r = - 0.288, p = 0.023). CMR-FT based LV and LA deformation performance could early detect cardiac involvement in IIM patients with preserved LVEF.

Left ventricular strain derived from cardiac magnetic resonance can predict outcomes of pulmonary valve replacement in patients with repaired tetralogy of Fallot.

PurposeSeveral adults with repaired tetralogy of Fallot (rToF) undergo pulmonary valve replacement (PVR) to reduce the right ventricular volume and retain right ventricular function. However, there is currently no consensus on the ideal time for PVR surgery in asymptomatic patients with rTOF with pulmonary regurgitation (PR). Clinical outcomes after PVR are also indeterminate. Recently, myocardial strain and strain rate derived from cardiac magnetic resonance (CMR) feature tracking were found to be more sensitive to right ventricular dysfunction than conventional parameters and therefore may add prognostic value in patients with rToF. We aimed to analyze whether pre-PVR left ventricular (LV) strain and strain rate detected by CMR feature tracking are associated with midterm outcomes after PVR in patients with rToF.MethodsSeventy-eight asymptomatic patients with rToF who required PVR due to moderate or severe PR were prospectively enrolled between January 2014 and June 2020. CMR cine sequences were obtained, and feature tracking parameters were measured preoperatively. Adverse events were documented during the follow-up. Receiver operating characteristic analysis was performed to determine the cutoff value. Kaplan–Meier curves were drawn with log-rank statistics; moreover, univariate and multivariate Cox proportional hazards regression analyses and Harrel C-indices were analyzed.ResultsDuring 3.6 ± 1.8 years of follow-up, 25 adverse events were recorded. Kaplan–Meier survival curves and univariate Cox analysis verified that patients with significantly reduced radial strain (RS), circumferential strain (CS), longitudinal strain (LS), RS rate at systole and diastole (RSRs and RSRe), and circumferential and LS rates at diastole (CSRe and LSRe) had worse event-free survival. After multivariate correction, only LS and LSRe remained significantly associated with adverse outcomes (hazard ratio = 1.243 [1.083–1.428] and 0.067 [0.017–0.258], respectively, all p < 0.05). The cutoff values of LS and LSRe were −12.30 (%) and 1.07 (s–1), respectively.ConclusionThe LV strain and strain rate prior to PVR are important prognostic factors for adverse events after PVR in rToF.

Incremental prognostic value of left atrial strain in patients with heart failure.

The present study aimed to evaluate the prognostic value of atrial strain and strain rate (SR) parameters derived from cardiac magnetic resonance (CMR) feature tracking (FT) in patients with ischaemic and non-ischaemic dilated cardiomyopathy with heart failure with reduced ejection fraction (HFrEF) but without atrial fibrillation. A total of 300 patients who underwent CMR with left ventricular ejection fraction (LVEF)≤40% and ischaemic or non-ischaemic dilated cardiomyopathy were analysed in this retrospective study. Major adverse cardiac events (MACEs) include cardiovascular death, heart transplantation, and rehospitalization for worsening HF. Ninety-four patients had MACEs during median follow-up of 3.84years. Multivariate Cox regression models adjusted for common clinical and CMR risk factors detected a significant association between LA-εs and MACE in ischaemic (HR=0.94/%; P=0.002), non-ischaemic dilated cardiomyopathy (HR=0.88/%; P=0.001), or all included patients (HR=0.87; P<0.001). LA-εs provided incremental prognostic value over conventional outcome predictors (Uno C statistical comparison model: from 0.776 to 0.801, P<0.0001; net reclassification improvement: 0.075, 95% CI: 0.0262-0.1301). Kaplan-Meier analysis revealed that the risk of MACE occurrence increased significantly with lower tertiles of left atrial reservoir strain (LA-εs) (log-rank P<0.0001). Patients in the worst LA-εs tertile faced a significantly increased risk of MACEs irrespective of late gadolinium enhancement (LGE) (log-rank P<0.0001). LA-εs derived from CMR FT has a significant prognostic impact on patients with ischaemic or non-ischaemic dilated cardiomyopathy, incremental to common clinical and CMR risk-factors.

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.

Comparison of Diagnostic Value Between STE+LDDSE and CMR-FT for Evaluating Coronary Microvascular Obstruction in Post-PCI Patients for STEMI.

BackgroundCoronary microvascular obstruction (CMVO) is closely associated with poor prognosis of ST-segment elevation myocardial infarction (STEMI) patients. However, data showing the comparison between cardiac magnetic resonance feature tracking (CMR-FT) and speckle tracking echocardiography (STE) combined with low-dose dobutamine stress echocardiography (LDDSE) in evaluating CMVO was scarcely available. We aimed to explore and compare the predictive value between CMR-FT and STE+LDDSE in detecting CMVO.MethodsSixty-one STEMI patients were executed cardiac magnetic resonance and echocardiography within the first 5–7 days after primary percutaneous coronary intervention (PCI). The myocardial strain analysis was performed in STE, STE+LDDSE, and CMR-FT, and strain parameters included radial strain (RS), circumferential strain (CS), and longitudinal strain (LS). ROC curves were performed to predict infarcted myocardium segments with CMVO.ResultsFinally, 324 infarcted myocardium segments were analyzed, including 100 infarcted segments with CMVO and 224 segments without CMVO by the gold standard assessment of late gadolinium-enhancement cardiac magnetic resonance imaging (LGE-CMR). The results showed that CS was generally superior to RS and LS in identifying CMVO. CS in CMR-FT facilitated the detection of CMVO, with a sensitivity, specificity, and accuracy of 78.00%, 81.25%, and 80.25%, respectively. The sensitivity, specificity, and accuracy of CS in STE combined with LDDSE were better than STE alone (76.00% vs 60.00%, 79.91% vs 64.29%, and 78.70% vs 62.96%, P < 0.05). In addition, CMR-FT is not superior to STE+LDDSE for detection of CMVO (P > 0.05).ConclusionLow-dose dobutamine can improve the clinical value of STE for evaluating CMVO in STEMI patients. Compared with CMR-FT, STE+LDDSE might be a better choice for STEMI patients because of its safety, convenience, and low-cost.

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation.

Atrial fibrillation (AF) is the most common form of arrhythmia. Atrial remodeling is considered the most critical mechanism for the presence and development of atrial fibrillation. Also, atrial remodeling can lead to the enlargement and dysfunction of the left atrium (LA), resulting in thrombosis and heart failure. Functional changes in left atrial strain and strain rate occur before structural alterations and are closely associated with structural remodeling and left atrial fibrosis. These parameters are sensitive biomarkers for atrial function. Cardiac magnetic resonance feature tracking (CMR-FT) is a novel, non-invasive, post-processing technique that can evaluate left atrial strain and strain rate. The CMR-FT was utilized in this investigation to assess the bilateral atrium strain rate in individuals with paroxysmal AF. Modifications in each segmental strain were evaluated using segmental analysis. The CMR-FT is recommended for non-invasive evaluations in the clinical assessment of atrial strain among existing strain imaging techniques. Further, it is a flexible parameter measurement with good reproducibility, high soft-tissue resolution, and post-processing based on standard cine balanced steady-state free precision (bSSFP) long-axis images without requiring a new sequence acquisition.

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation

Atrial fibrillation (AF) is the most common form of arrhythmia. Atrial remodeling is considered the most critical mechanism for the presence and development of atrial fibrillation. Also, atrial remodeling can lead to the enlargement and dysfunction of the left atrium (LA), resulting in thrombosis and heart failure. Functional changes in left atrial strain and strain rate occur before structural alterations and are closely associated with structural remodeling and left atrial fibrosis. These parameters are sensitive biomarkers for atrial function. Cardiac magnetic resonance feature tracking (CMR-FT) is a novel, non-invasive, post-processing technique that can evaluate left atrial strain and strain rate. The CMR-FT was utilized in this investigation to assess the bilateral atrium strain rate in individuals with paroxysmal AF. Modifications in each segmental strain were evaluated using segmental analysis. The CMR-FT is recommended for non-invasive evaluations in the clinical assessment of atrial strain among existing strain imaging techniques. Further, it is a flexible parameter measurement with good reproducibility, high soft-tissue resolution, and post-processing based on standard cine balanced steady-state free precision (bSSFP) long-axis images without requiring a new sequence acquisition.

Multi-parametric analyses to investigate dependencies of normal left atrial strain by cardiovascular magnetic resonance feature tracking

Left-atrial (LA) strain is the result of complex hemodynamics, which may be better characterized using a multiparametric approach. Cardiovascular magnetic resonance (CMR) feature tracking was used to perform a comprehensive LA strain assessment of 183 enrolled healthy volunteers (11–70 years, 97 females, median 32.9 ± 28.3 years). Novel strain dependencies were assessed using multi-parametric regression (MPR) analyses. LA volumetric data, left ventricular strain, transmitral and pulmonary venous blood flow parameters were utilized to create clusters for MPR of all subjects and a heart rate controlled subgroup (pulse: 60–75/min, N = 106). The LA reservoir(r) and conduit(c) strains of the total cohort were significantly elevated (p ≤ 0.001) in women (r: 49.7 ± 12.9%, c: 32.0 ± 11.0%) compared to men (r: 42.9 ± 11.4%, c: 26.1 IQ 10.5%). In contrast, there were no gender-specific differences (p > 0.05) for subgroup LA reservoir, conduit and booster(b) strains (all, r: 47.3 ± 12.7%; c: 29.0 IQ 15.5%; b: 17.6 ± 5.4%) and strain rates (all, 2.1 IQ 1.0 s−1; − 2.9 IQ 1.5 s−1; − 2.3 IQ 1.0 s−1). MPR found large effect sizes (|R2|≥ 0.26) for correlations between strain and various cardiac functional parameters. Largest effect size was found for the association between LA conduit strain and LA indexed booster volume, LA total ejection fraction, left ventricular global radial strain and E-wave (|R2|= 0.437). In addition to providing normal values for sex-dependent LA strain and strain rate, no gender differences were found with modified heart rate. MPR analyses of LA strain/strain rate and various cardiac functional parameters revealed that heart rate control improved goodness-of-fit for the overall model.

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

BackgroundMicrovascular obstruction (MVO) and Late Gadolinium Enhancement (LGE) assessed in cardiac magnetic resonance (CMR) are associated with adverse outcome in patients with ST-elevation myocardial infarction (STEMI). Our aim was to analyze the diagnostic performance of segmental strain for the detection of MVO and LGE.MethodsPatients with anterior STEMI, who underwent additional CMR were enrolled in this sub-study of the CARE-AMI trial. Using CMR feature tracking (FT) segmental circumferential peak strain (SCS) was measured and the diagnostic performance of SCS to discriminate MVO and LGE was assessed in a derivation and validation cohort.ResultsForty-eight STEMI patients (62 ± 12 years old), 39 (81%) males, who underwent CMR (i.e., mean 3.0 ± 1.5 days) after primary percutaneous coronary intervention (PCI) were included. All patients presented with LGE and in 40 (83%) patients, MVO was additionally present. Segments in all patients were visually classified and 146 (19%) segments showed MVO (i.e., LGE+/MVO+), 308 (40%) segments showed LGE and no MVO (i.e., LGE+/MVO–), and 314 (41%) segments showed no LGE (i.e., LGE–). Diagnostic performance of SCS for detecting MVO segments (i.e., LGE+/MVO+ vs. LGE+/MVO–, and LGE–) showed an AUC = 0.764 and SCS cut-off value was –11.2%, resulting in a sensitivity of 78% and a specificity of 67% with a positive predictive value (PPV) of 30% and a negative predictive value (NPV) of 94% when tested in the validation group. For LGE segments (i.e., LGE+/MVO+ and LGE+/MVO– vs. LGE–) AUC = 0.848 and SCS with a cut-off value of –13.8% yielded to a sensitivity of 76%, specificity of 74%, PPV of 81%, and NPV of 70%.ConclusionSegmental strain in STEMI patients was associated with good diagnostic performance for detection of MVO+ segments and very good diagnostic performance of LGE+ segments. Segmental strain may be useful as a potential contrast-free surrogate marker to improve early risk stratification in patients after primary PCI.

Regional left ventricular endocardial strains estimated from low-dose 4DCT: Comparison with cardiac magnetic resonance feature tracking.

Estimates of regional left ventricular (LV) strains provide additional information to global function parameters such as ejection fraction (EF) and global longitudinal strain (GLS) and are more sensitive in detecting abnormal regional cardiac function. The accurate and reproducible assessment of regional cardiac function has implications in the management of various cardiac diseases such as heart failure, myocardial ischemia, and dyssynchrony. To develop a method that yields highly reproducible, high-resolution estimates of regional endocardial strains from 4DCT images. A method for estimating regional LV endocardial circumferential and longitudinal ( ) strains from 4DCT was developed. Point clouds representing the LV endocardial surface were extracted for each time frame of the cardiac cycle from 4DCT images. 3D deformation fields across the cardiac cycle were obtained by registering the end diastolic point cloud to each subsequent point cloud in time across the cardiac cycle using a 3D point-set registration technique. From these deformation fields, were estimated over the entire LV endocardial surface by fitting an affine transformation with maximum likelihood estimation. The 4DCT-derived strains were compared with strains estimated in the same subjects by cardiac magnetic resonance (CMR); twenty-four subjects had CMR scans followed by 4DCT scans acquired within a few hours. Regional LV circumferential and longitudinal strains were estimated from the CMR images using a commercially available feature tracking software (cvi42). Global circumferential strain (GCS) and global longitudinal strain (GLS) were calculated as the mean of the regional strains across the entire LV for both modalities. Pearson correlation coefficients and Bland-Altman analyses were used for comparisons. Intraclass correlation coefficients (ICC) were used to assess the inter- and intraobserver reproducibility of the 4DCT-derived strains. The 4DCT-derived regional strains correlated well with the CMR-derived regional strains ( : r=0.76, p<0.001; : r=0.64, p<0.001). A very strong correlation was found between 4DCT-derived GCS and 4DCT-derived EF (r=-0.96; p<0.001). The 4DCT-derived strains were also highly reproducible, with very low inter- and intraobserver variability (intraclass correlation coefficients in the range of [0.92, 0.99]). We have developed a novel method to estimate high-resolution regional LV endocardial circumferential and longitudinal strains from 4DCT images. Except for the definition of the mitral valve and LV outflow tract planes, the method is completely user independent, thus yielding highly reproducible estimates of endocardial strain. The 4DCT-derived strains correlated well with those estimated using a commercial CMR feature tracking software. The promising results reported in this study highlight the potential utility of 4DCT in the precise assessment of regional cardiac function for the management of cardiac disease.

Prognostic Value of Left Atrial Reservoir Strain in Left Ventricular Myocardial Noncompaction: A 3.0 T Cardiac Magnetic Resonance Feature Tracking Study.

The relationship of left atrial (LA) strain to high-risk heart failure (HF) events in patients with left ventricular myocardial noncompaction (LVNC) remains to be thoroughly investigated. To evaluate the LA performance in patients with LVNC, and to investigate the prognostic value of LA phasic strain on high-risk HF events, and its influencing factors. Retrospective. A total of 95 LVNC patients (74 with LA enlargement [LAE] and 21 without LAE) and 50 healthy controls. A 3.0 T, balanced steady-state free-precession cine imaging. LA longitudinal strains were measured by cardiac MRI feature tracking technique. LA volume index (LAVI) and LA ejection fraction (LAEF) were calculated. Their intraobserver and interobserver reproducibility were evaluated. The primary outcome was high-risk HF events, a composite of first HF hospitalization, hospitalization for worsening HF and death from HF. Student's t/Mann-Whitney U, one-way analysis of variance/Kruskal-Wallis, Chi-squared, receiver operating characteristic, Kaplan-Meier, log-rank, Cox regression, Pearson and Spearman correlation and linear regression analyses were performed. The significance threshold was set at P < 0 .05. LAEF and LA longitudinal strains decreased in LVNC patients irrespective of the presence of LAE. During a median follow-up of 32.17months, high-risk HF occurred in 13 (13.68%) patients. Patients with increased LAVI, decreased LAEF and decreased LA longitudinal strain had significantly higher risks of high-risk HF events. In patients with LVNC, LA reservoir strain (εs) was independently associated with high-risk HF (hazard ratio=23.208 [95% CI: 2.993-179.967]). LV global longitudinal strain (LV GLS) (β=-1.783 [95% CI: -2.493 to -1.073]) was significantly and independently associated with εs. Intraobserver and interobserver reproducibility was excellent for LAVI, LAEF, and LA strain. In patients with LVNC, εs was an independent predictor for high-risk HF events. LV GLS was an independent determinant of εs in LVNC. 4 TECHNICAL EFFICACY: Stage 4.