Validation of cardiac magnetic resonance tissue tracking in the rapid assessment of RV function: a comparative study to echocardiography

Echocardiographic determination of right ventricular volumes and ejection fraction: Validation of a truncated cone and rhomboid pyramid formula

BACKGROUND

Echocardiographic assessment of right ventricular (RV) measurements may be challenging. The aim of this study was to develop a formula for calculation of RV volumes and function based on measurements of linear dimensions by 2-dimensional (2D) transthoracic echocardiography (TTE) in comparison to cardiovascular magnetic resonance (CMR).

METHODS

129 consecutive patients with standard TTE and RV analysis by CMR were included. A formula based on the geometric assumptions of a truncated cone minus a truncated rhomboid pyramid was developed for calculations of RV end-diastolic volume (EDV) and RV end-systolic volume (ESV) by using the basal diameter of the RV (Dd and Ds) and the baso-apical length (Ld and Ls) in apical 4-chamber TTE views: RV EDV = 1.21 * Dd2 * Ld, and RV ESV = 1.21 * Ds2 * Ls.

RESULTS

Calculations of RV EDV (ΔRV EDV = 10.2±26.4 ml to CMR, r = 0.889), RV ESV (ΔRV ESV = 4.5±18.4 ml to CMR, r = 0.921) and RV EF (ΔRV EF = 0.5±4.0% to CMR, r = 0.905) with the cone-pyramid formula (CPF) highly agreed with CMR. Impaired RV function on CMR (n = 52) was identified with a trend to higher accuracy by CPF than by conventional echocardiographic parameters (tricuspid annular plane systolic excursion (TAPSE) and fractional area change (FAC)).

CONCLUSION

Calculations of RV volumes and RV function by 2D TTE with the newly developed CPF were in high concordance to measurements by CMR. Accuracy for detection of patients with reduced RV function were higher by the proposed 2D TTE CPF method than by conventional echocardiographic parameters of TAPSE and RV FAC.

Diagnostic accuracy of cardiovascular magnetic resonance strain analysis and atrial size to identify heart failure with preserved ejection fraction

Aims

Heart failure with preserved ejection fraction (HFpEF) continues to be a diagnostic challenge. Cardiac magnetic resonance atrial measurement, feature tracking (CMR-FT), tagging has long been suggested to diagnose HFpEF and potentially complement echocardiography especially when echocardiography is indeterminate. Data supporting the use of CMR atrial measurements, CMR-FT or tagging, are absent. Our aim is to conduct a prospective case-control study assessing the diagnostic accuracy of CMR atrial volume/area, CMR-FT, and tagging to diagnose HFpEF amongst patients suspected of having HFpEF.

Methods and results

One hundred and twenty-one suspected HFpEF patients were prospectively recruited from four centres. Patients underwent echocardiography, CMR, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements within 24 h to diagnose HFpEF. Patients without HFpEF diagnosis underwent catheter pressure measurements or stress echocardiography to confirm HFpEF or non-HFpEF. Area under the curve (AUC) was determined by comparing HFpEF with non-HFpEF patients. Fifty-three HFpEF (median age 78 years, interquartile range 74-82 years) and thirty-eight non-HFpEF (median age 70 years, interquartile range 64-76 years) were recruited. Cardiac magnetic resonance left atrial (LA) reservoir strain (ResS), LA area index (LAAi), and LA volume index (LAVi) had the highest diagnostic accuracy (AUCs 0.803, 0.815, and 0.776, respectively). Left atrial ResS, LAAi, and LAVi had significantly better diagnostic accuracy than CMR-FT left ventricle (LV)/right ventricle (RV) parameters and tagging (P < 0.01). Tagging circumferential and radial strain had poor diagnostic accuracy (AUC 0.644 and 0.541, respectively).

Conclusion

Cardiac magnetic resonance LA ResS, LAAi, and LAVi have the highest diagnostic accuracy to identify HFpEF patients from non-HFpEF patients amongst clinically suspected HFpEF patients. Cardiac magnetic resonance feature tracking LV/RV parameters and tagging had low diagnostic accuracy to diagnose HFpEF.

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

BACKGROUND

Right ventricular (RV) dysfunction in patients with non-ischemic dilated cardiomyopathy (NICM) is associated with cardiovascular events. To analyze the feasibility of assessing RV myocardial deformation by feature tracking (FT)-cardiac magnetic resonance (CMR), and its usefulness as a prognostic marker.

METHODS

Retrospective study of NICM patients undergoing CMR. Longitudinal FT-RV free wall (LFT-RVFW) and fractional area change (FAC) were obtained. Correlation with standard RV parameters was studied. An association with combined event (heart failure (HF), ICD implantation or cardiovascular death) was assessed using a logistic regression model.

RESULTS

98 patients (64 ± 13 years) were included. Left ventricular (LV) systolic function (LVEF 29.5 ± 9.6%, 47% with LVEF ≥ 30%) and RV (RVEF 52.2 ± 14.6%, 72% with RVEF ≥ 45%). Follow-up of 38 ± 17 months, 26.5% presented at least one admission for HF. An excellent correlation of LFT-RVFW (r = 0.82) and FAC (r = 0.83) with RVEF was evident. No association of RV-FT parameters with prognosis entire study population was found. However, in patients with LVEF ≥ 30%, admissions for HF were associated with lower LFT-RVFW (-21.6 ± 6.6% vs -31.3 ± 10%; p = 0.006) and FAC (36.6 ± 9.6% vs 50.5 ± 13.4%; p < 0.001) values. Similar differences were observed when only patients with RVEF ≥ 45% were considered. An LFT-RVFW cut-off point of -19.5% and FAC of 36.5% showed good prognostic performance. Decreased LFT-RVFW or FAC represented an independent predictor of combined event in patients with LVEF ≥ 30%.

CONCLUSIONS

In NICM patients without severe LV dysfunction, decreased values of LFT-RVFW and/or FAC were associated with HF admissions, independently of RVEF.

Assessment of right ventricular remodeling in chronic thromboembolic pulmonary hypertension by 2D-speckle tracking echocardiography: A comparison with cardiac magnetic resonance

Background

Right heart remodeling occurs in a substantial proportion of patients with chronic thromboembolic pulmonary hypertension (CTEPH) and significantly affects their prognosis. Two-dimensional speckle-tracking echocardiography (2D-STE) can be used to evaluate myocardial deformation under physiological and pathological conditions. This study aimed to assess the feasibility of 2D-STE for evaluating right ventricular (RV) remodeling in CTEPH patients.

Methods

This retrospective study included 21 CTEPH patients who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR). Data for the following parameters that can reflect RV function were collected: tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), right ventricular index of myocardial performance (RIMP), peak systolic velocity of the tricuspid annulus (S'), and CMR-right ventricular ejection fraction (CMR-RVEF). The following strain parameters were calculated using post-processing software: STE-RV global longitudinal strain (STE-RVGLS), STE-RV free wall longitudinal strain (STE-RVFWLS), and CMR-RVGLS.

Results

As CMR-RVEF deteriorated, RV remodeling in CTEPH patients became more apparent and was mainly characterized by significant enlargement of the RV, weakening of myocardial deformation, and a decrease in RV contractility (RV area, STE-RVFWLS, STE-RVGLS: mild vs. severe and moderate vs. severe, p < 0.05; CMR-RVGLS: mild vs. severe, p < 0.05; TAPSE: moderate vs. severe, p < 0.05). Moreover, the Pearson correlation coefficient for correlation with CMR-derived RVEF was stronger for RVFWLS than for CMR-GLS (r-value: 0.70 vs. 0.68), and the strain values measured by 2D-STE showed a weak correlation with right heart catheterization data. Bland-Altman analysis showed good agreement between 2D-STE and CMR-feature tracking (FT) for RVGLS (bias = -0.96; 95% limit of agreement from -8.42 to 6.49).

Conclusions

For the measurement of RVGLS, 2D-STE is similarly feasible to CMR-FT and could sensitively identify right heart remodeling.

Effects of Sodium-Glucose Co-Transporter-2 Inhibition on Pulmonary Arterial Stiffness and Right Ventricular Function in Heart Failure with Reduced Ejection Fraction

Background and Objectives: In addition to left ventricular (LV) functions, right ventricular (RV) functions and pulmonary arterial stiffness (PAS) may be adversely affected in patients with heart failure with reduced ejection fraction (HFrEF). Sodium-glucose co-transporter-2 (SGLT2) inhibitor therapy positively affects LV functions as well as having functional and symptomatic benefits in HFrEF patients. In this study, we aimed to evaluate the effects of SGLT2 inhibitor treatment on RV function and PAS in HFrEF patients. Materials andMethods: 168 HFrEF patients with New York Heart Association (NYHA) class ≥2 symptoms despite optimal medical treatment and who were started on SGLT2 inhibitor therapy were included in this retrospective study. NYHA classification, N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, Minnesota Living with Heart Failure Questionnaire (MLWHFQ) scores, laboratory tests, and transthoracic echocardiography (TTE) measurements were recorded before treatment and at the end of the 6-month follow-up. Results: The mean age of the patients was 62.7 ± 11.4 years, and 38 (22.6%) were women. RV function (RV fractional area change (FAC) (33.8 ± 6.4% vs. 39.2 ± 7.3%, p < 0.001); tricuspid annular plane systolic excursion (TAPSE) (18.4 ± 3.8 mm vs. 19.6 ± 3.6 mm, p < 0.001); RV S’ (10 (8 − 13) cm/s vs. 13 (10 − 16) cm/s, p < 0.001); RV myocardial performance index (RV MPI) (0.68 ± 0.12 vs. 0.59 ± 0.11, p < 0.001); mean pulmonary artery pressure (mPAP) (39.6 ± 7.8 mmHg vs. 32 ± 6.8 mmHg, p = 0.003)) and PAS (24.2 ± 4.6 kHz/ms vs. 18.6 ± 3.1 kHz/ms, p < 0.001) values at the 6-month follow-up after SGLT2 inhibitor therapy significantly improved. It was found that SGLT2 inhibitor treatment provided significant improvement in NYHA classification, MLWHFQ scores, and NT-proBNP levels (2876 ± 401 vs. 1034 ± 361, p < 0.001), and these functional and symptomatic positive changes in HFrEF patients were significantly correlated with positive changes in LVEF, PAS, and RV functional status. Conclusions: SGLT2 inhibitor treatment results in symptomatic and functional well-being in HFrEF patients, as well as positive changes in RV function and PAS.

Evaluation and Comparison of Quantitative Right Ventricular Strain Assessment by Cardiac Magnetic Resonance in Pulmonary Hypertension Using Feature Tracking and Deformable Registration Algorithms

RATIONALE AND OBJECTIVE

Deformable registration algorithms (DRA) has been used to detect left ventricular myocardial changes, however, its clinical utility in right ventricular (RV) function has not been evaluated. In this study, we aim to evaluate and compare quantitative RV strain assessment by cardiac magnetic resonance in pulmonary hypertension (PH) using feature tracking (FT) and DRA.

MATERIALS AND METHODS

Thirty patients were confirmed to have PH using right heart catheterization, and 16 healthy controls were evaluated with cardiac magnetic resonance. Global and segmental RV strain was measured by DRA and FT methods. Intraclass correlation coefficients (ICCs), coefficient of variation, and Bland-Altman analysis were used to assess and compare the interobserver and intraobserver variability of the DRA and FT methods.

RESULTS

DRA was more sensitive than FT in the detection of RV circumferential and septal dysfunction. The global longitudinal strain (GLS) obtained by the two methods was reduced in mild-moderate PH patients (mean pulmonary artery pressure≤45 mm Hg), and the GLS and global circumferential strain (GCS) were reduced in severe PH patients (mean pulmonary artery pressure >45 mm Hg). DRA and FT methods demonstrate similar observer agreement in global strain using ICC (ICC greater than 0.90), but RV strain derived from DRA had lower variability using COV ([8%-14%] for DRA versus [11%-39%] for FT).For segmental longitudinal strain, DRA showed higher ICC and lower COV compared with that of the FT method. Correlations between RVEF and RV global strain parameters were strong (p < 0.01):GLS-DRA, r = -0.696; GLS-FT, r = -0.832; GCS-DRA, r = -0.745; and GCS-FT, r = -0.817. GLS-DRA was weakly correlated with mPAP (r = 0.385, p < 0.05).In multiple linear regression analysis, RVEF and mPAP were independent predictors of GLS-DRA (R² = 0.57, p < 0.01).

CONCLUSIONS

The DRA method is more sensitive and robust for RV myocardial strain measurements than FT method.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

The Association Between Notching of the Right Ventricular Outflow Tract Flow Velocity Doppler Envelope and Impaired Right Ventricular Function After Acute High-Altitude Exposure

Introduction

Pulmonary artery pressure (PAP) is increased and right ventricular (RV) function is well preserved in healthy subjects upon exposure to high altitude (HA). An increase in PAP may trigger notching of the right ventricular outflow tract Doppler flow velocity envelope (RVOT notch), which is associated with impaired RV function in patients with pulmonary hypertension. However, whether HA exposure can induce RVOT notch formation and the subsequent impact on cardiac function in healthy subjects remains unclear.

Methods

A total of 99 subjects (69 males and 30 females) with a median age of 25 years were enrolled in this study; they traveled from 500 to 4100 m by bus over a 2-day period. All subjects underwent a comprehensive physiological and echocardiographic examination 1 day before ascension at low altitude and 15 ± 3 h after arrival at HA. The RVOT notch was determined by the presence of a notched shape in the RVOT Doppler flow velocity envelope. The systolic PAP (SPAP) was calculated as Bernoulli equation SPAP = 4 × (maximum tricuspid regurgitation velocity)²+5 and mean PAP (mPAP) = 0.61 × SPAP+2. Cardiac output was calculated as stroke volume × heart rate. Pulmonary capillary wedge pressure (PCWP) was calculated as 1.9+1.24 × mitral E/e’. Pulmonary vascular resistance (PVR) was calculated as (mPAP-PCWP)/CO.

Results

After HA exposure, 20 (20.2%) subjects had an RVOT notch [notch (+)], and 79 (79.8%) subjects did not have an RVOT notch [notch (−)]. In the multivariate logistic regression analysis, the SPAP, right ventricular global longitude strain (RV GLS), and tricuspid E/A were independently associated with the RVOT notch. The SPAP, mPAP, PVR, standard deviations of the times to peak systolic strain in the four mid-basal RV segments (RVSD4), peak velocity of the isovolumic contraction period (ICV), and the peak systolic velocity (s’) at the mitral/tricuspid annulus were increased in all subjects. Conversely, the pulse oxygen saturation (SpO₂), RV GLS, and tricuspid annulus plane systolic excursion (TAPSE)/SPAP were decreased. However, the increases of SPAP, mPAP, PVR, and RVSD4 and the decreases of SpO₂, RV GLS, and TAPSE/SPAP were more pronounced in the notch (+) group than in the notch (−) group. Additionally, increased tricuspid ICV and mitral/tricuspid s’ were found only in the notch (−) group.

Conclusion

HA exposure-induced RVOT notch formation is associated with impaired RV function, including no increase in the tricuspid ICV or s’, reduction of RV deformation, deterioration in RV-pulmonary artery coupling, and RV intraventricular synchrony.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Myocardial strain analysis of the right ventricle: comparison of different cardiovascular magnetic resonance and echocardiographic techniques

BACKGROUND

Right ventricular (RV) strain is a useful predictor of prognosis in various cardiovascular diseases, including those traditionally believed to impact only the left ventricle. We aimed to determine inter-modality and inter-technique agreement in RV longitudinal strain (LS) measurements between currently available cardiovascular magnetic resonance (CMR) and echocardiographic techniques, as well as their reproducibility and the impact of layer-specific strain measurements.

METHODS

RV-LS was determined in 62 patients using 2D speckle tracking echocardiography (STE, Epsilon) and two CMR techniques: feature tracking (FT) and strain-encoding (SENC), and in 17 healthy subjects using FT and SENC only. Measurements included global and free-wall LS (GLS, FWLS). Inter-technique agreement was assessed using linear regression and Bland-Altman analysis. Reproducibility was quantified using intraclass correlation (ICC) and coefficients of variation (CoV).

RESULTS

We found similar moderate agreement between both CMR techniques and STE in patients: r = 0.57-0.63 for SENC; r = 0.50-0.62 for FT. The correlation between SENC and STE was better for GLS (r = 0.63) than for FWLS (r = 0.57). Conversely, the correlation between FT and STE was higher for FWLS (r = 0.60-0.62) than GLS (r = 0.50-0.54). FT-midmyocardial strain correlated better with SENC and STE than FT-subendocardial strain. The agreement between SENC and FT was fair (r = 0.36-0.41, bias: - 6.4 to - 10.4%) in the entire study group. All techniques except FT showed excellent reproducibility (ICC: 0.62-0.96, CoV: 0.04-0.30).

CONCLUSIONS

We found only moderate inter-modality agreement with STE in RV-LS for both FT and SENC and poor agreement when comparing between the CMR techniques. Different modalities and techniques should not be used interchangeably to determine and monitor RV strain.

Age- and gender-related normal references of right ventricular strain values by tissue tracking cardiac magnetic resonance: results from a Chinese population

Background

Myocardial deformation is a sensitive marker for sub-clinical myocardial dysfunction and carries independent prognostic significance across a broad range of cardiovascular diseases. Reproducible and repeatable assessment of right ventricular (RV) function is vital for monitoring congenital and acquired heart diseases. The purpose of this study was to determine the normal references of RV strain and strain rate values using tissue tracking cardiac magnetic resonance imaging (MRI).

Methods

A cohort of 120 normal human subjects from each decade of life between 20 and 70 without cardiac diseases were enrolled in this study. Retrospectively, electrocardiogram (ECG) gating cardiac MRI imaging was performed at 3.0T with balanced steady-state free precession (bSSFP) imaging. RV global and segmental myocardial strains were analyzed by tissue tracking by two experienced observers.

Results

The global peak longitudinal strain (GLS) and global peak radial strain (GRS) was -24.3±4.7 and 23.0±8.5 respectively. For the peak circumferential strains (GCS), the values for global, basal, mid-cavity, and apical segments were -13.3±4.1, -13.1±4.0, -12.5±4.7, and -15.9±5.8, respectively. There were significant gender differences in peak GRS (P=0.009) and at the base (P=0.017) and the mid-cavity (P=0.011) with greater deformation in females than in males. There were also significant age differences in GRS (P<0.001), GCS for basal (P<0.001), and mid-cavity segments (P=0.037). On Bland-Altman analysis, peak GLS and GRS had the best intra-observer agreement (mean bias, -0.13±0.51; 95% CI, -1.13-0.87) and inter-observer (mean bias, 0.054±0.31; 95% CI, -0.55-0.66) agreement, respectively.

Conclusions

Normal values of RV deformation for healthy individuals using tissue tracking cardiac magnetic resonance (CMR-TT) provided good RV peak strain reproducibility. There was a significant correlation between RV strain or strain rate parameters with either age or sex.