Cine Cardiovascular Magnetic Resonance Images Research Articles

Noninvasive Pressure-Volume Loops Predict Major Adverse Cardiac Events in Heart Failure With Reduced Ejection Fraction

BackgroundHeart failure with reduced ejection fraction (HFrEF) is characterized by ventricular remodeling and impaired myocardial energetics. Left ventricular pressure-volume (PV) loop analysis can be performed noninvasively using cardiovascular magnetic resonance (CMR) imaging to assess cardiac thermodynamic efficiency. ObjectivesThe aim of the study was to investigate whether noninvasive PV loop parameters, derived from CMR, could predict major adverse cardiac events (MACE) in HFrEF patients. MethodsPV loop parameters (stroke work, ventricular efficiency, external power, contractility, and energy per ejected volume) were computed from CMR cine images and brachial blood pressure. The primary end point was MACE (cardiovascular death, heart failure (HF) hospitalization, myocardial infarction, revascularization, ventricular tachycardia/fibrillation, heart transplantation, or left ventricular assist device implantation within 5 years). Associations between PV loop parameters and MACE were evaluated using multivariable Cox regression. ResultsOne hundred and sixty-four HFrEF patients (left ventricular ejection fraction ≤40%, age 63 [IQR: 55-70] years, 79% male) who underwent clinical CMR examination between 2004 and 2014 were included. Eighty-eight patients (54%) experienced at least one MACE after an average of 2.8 years. Unadjusted models demonstrated a significant association between MACE and all PV loop parameters (P < 0.05 for all), HF etiology (P < 0.001), left ventricular ejection fraction (P = 0.003), global longitudinal strain (P < 0.001), and N-terminal prohormone of brain natriuretic peptide level (P = 0.001). In the multivariable Cox regression analysis adjusted for age, sex, hypertension, diabetes, and HF etiology, ventricular efficiency was associated with MACE (HR: 1.04 (95% CI: 1.01-1.08) per-% decrease, P = 0.01). ConclusionsVentricular efficiency, derived from noninvasive PV loop analysis from standard CMR scans, is associated with MACE in patients with HFrEF.

Characteristics of pulmonary artery strain assessed by cardiovascular magnetic resonance imaging and associations with metabolomic pathways in human ageing.

Pulmonary artery (PA) strain is associated with structural and functional alterations of the vessel and is an independent predictor of cardiovascular events. The relationship of PA strain to metabolomics in participants without cardiovascular disease is unknown. In the current study, community-based older adults, without known cardiovascular disease, underwent simultaneous cine cardiovascular magnetic resonance (CMR) imaging, clinical examination, and serum sampling. PA global longitudinal strain (GLS) analysis was performed by tracking the change in distance from the PA bifurcation to the pulmonary annular centroid, using standard cine CMR images. Circulating metabolites were measured by cross-sectional targeted metabolomics analysis. Among n = 170 adults (mean age 71 ± 6.3 years old; 79 women), mean values of PA GLS were 16.2 ± 4.4%. PA GLS was significantly associated with age (β = -0.13, P = 0.017), heart rate (β = -0.08, P = 0.001), dyslipidemia (β = -2.37, P = 0.005), and cardiovascular risk factors (β = -2.49, P = 0.001). Alanine (β = -0.007, P = 0.01) and proline (β = -0.0009, P = 0.042) were significantly associated with PA GLS after adjustment for clinical risk factors. Medium and long-chain acylcarnitines were significantly associated with PA GLS (C12, P = 0.027; C12-OH/C10-DC, P = 0.018; C14:2, P = 0.036; C14:1, P = 0.006; C14, P = 0.006; C14-OH/C12-DC, P = 0.027; C16:3, P = 0.019; C16:2, P = 0.006; C16:1, P = 0.001; C16:2-OH, P = 0.016; C16:1-OH/C14:1-DC, P = 0.028; C18:1-OH/C16:1-DC, P = 0.032). By conventional CMR, PA GLS was associated with aging and vascular risk factors among a contemporary cohort of older adults. Metabolic pathways involved in PA stiffness may include gluconeogenesis, collagen synthesis, and fatty acid oxidation.

Kiosk 8R-FB-10 - Exploration of Geometric Deep Learning FBom 3D Cardiac Shape Models for the Classification of Cardiac Amyloid Sub-type FBom 2D Cine Cardiovascular Magnetic Resonance Imaging

Kiosk 8R-FB-10 - Exploration of Geometric Deep Learning FBom 3D Cardiac Shape Models for the Classification of Cardiac Amyloid Sub-type FBom 2D Cine Cardiovascular Magnetic Resonance Imaging

The influence of symptom-to-reperfusion-time on left ventricular strain and extent of infarction in patients with STEMI: a 3-dimensional view on the wavefront phenomenon

Abstract Aims Data on the relationship between time-to-reperfusion and left ventricular (LV) function and infarct characteristics after ST-segment elevation myocardial infarction (STEMI) are inconsistent and not completely understood. Therefore, we examined the association between the symptom-to-reperfusion-time and cardiovascular magnetic resonance (CMR) derived global strain parameters and infarct extent in STEMI patients. Methods and results The study included 108 STEMI patients who underwent successful primary percutaneous coronary intervention (PPCI). Patients were categorized according to the median symptom-to-reperfusion-time: shorter (&amp;lt;160min, n=54) and longer times (&amp;gt;160min, n=54). CMR was performed 2-7 days after PPCI and at 1-month. CMR cine imaging was performed for functional assessment and late gadolinium enhancement (LGE) to evaluate infarct extent. Myocardial feature-tracking was used for global LV strain analysis. Mean transmural extent score was quantified per patient as the average of infarct percentages for all segments containing hyperenhanced tissue. Baseline clinical and angiographic characteristics were comparable between the groups. Patients with shorter reperfusion time had more favorable baseline and follow-up LV circumferential and radial strain (p=0.049, p=0.01, p=0.047, p&amp;lt;0.01, respectively), while LV longitudinal strain appeared comparable for both baseline and follow-up (p&amp;gt;0.05 for both, Figure 1). Mean transmural extent score at follow-up was lower in patients with shorter reperfusion time (p&amp;lt;0.01). In multivariable regression analysis including all 3 strain directions, baseline LV circumferential strain was independently associated with mean transmural extent score at follow-up (β=1.89, p&amp;lt;0.001). Conclusion In STEMI patients, time-to-reperfusion was significantly associated with smaller extent of infarction and better LV circumferential and radial strain but not with longitudinal strain. Moreover, infarct transmurality and residual LV circumferential strain are closely linked.Comparison of BL and FU global LV strainGraphical abstract

Automated segmentation of 3D cine cardiovascular magnetic resonance imaging.

As the life expectancy of children with congenital heart disease (CHD) is rapidly increasing and the adult population with CHD is growing, there is an unmet need to improve clinical workflow and efficiency of analysis. Cardiovascular magnetic resonance (CMR) is a noninvasive imaging modality for monitoring patients with CHD. CMR exam is based on multiple breath-hold 2-dimensional (2D) cine acquisitions that should be precisely prescribed and is expert and institution dependent. Moreover, 2D cine images have relatively thick slices, which does not allow for isotropic delineation of ventricular structures. Thus, development of an isotropic 3D cine acquisition and automatic segmentation method is worthwhile to make CMR workflow straightforward and efficient, as the present work aims to establish. Ninety-nine patients with many types of CHD were imaged using a non-angulated 3D cine CMR sequence covering the whole-heart and great vessels. Automatic supervised and semi-supervised deep-learning-based methods were developed for whole-heart segmentation of 3D cine images to separately delineate the cardiac structures, including both atria, both ventricles, aorta, pulmonary arteries, and superior and inferior vena cavae. The segmentation results derived from the two methods were compared with the manual segmentation in terms of Dice score, a degree of overlap agreement, and atrial and ventricular volume measurements. The semi-supervised method resulted in a better overlap agreement with the manual segmentation than the supervised method for all 8 structures (Dice score 83.23 ± 16.76% vs. 77.98 ± 19.64%; P-value ≤0.001). The mean difference error in atrial and ventricular volumetric measurements between manual segmentation and semi-supervised method was lower (bias ≤ 5.2 ml) than the supervised method (bias ≤ 10.1 ml). The proposed semi-supervised method is capable of cardiac segmentation and chamber volume quantification in a CHD population with wide anatomical variability. It accurately delineates the heart chambers and great vessels and can be used to accurately calculate ventricular and atrial volumes throughout the cardiac cycle. Such a segmentation method can reduce inter- and intra- observer variability and make CMR exams more standardized and efficient.

Impact of symptom-to-reperfusion-time on transmural infarct extent and left ventricular strain in patients with ST-segment elevation myocardial infarction: a 3D view on the wavefront phenomenon.

We examined the association between the symptom-to-reperfusion-time and cardiovascular magnetic resonance (CMR)-derived global strain parameters and transmural infarct extent in ST-segment elevation myocardial infarction (STEMI) patients. The study included 108 STEMI patients who underwent successful primary percutaneous coronary intervention (PPCI). Patients were categorized according to the median symptom-to-reperfusion-time: shorter (<160 min, n = 54) and longer times (>160 min, n = 54). CMR was performed 2-7 days after PPCI and at 1 month. CMR cine imaging was performed for functional assessment and late gadolinium enhancement to evaluate transmural infarct extent. Myocardial feature-tracking was used for strain analysis. Groups were comparable in relation to incidence of LAD disease and pre- and post-PPCI thrombolysis in myocardial infarction (TIMI) flow grades. The mean transmural extent score at follow-up was lower in patients with shorter reperfusion time (P < 0.01). Both baseline and follow-up maximum transmural extent scores were smaller in patients with shorter reperfusion time (P = 0.03 for both). Patients with shorter reperfusion time had more favourable global left ventricular (LV) circumferential strain (baseline, P = 0.049; follow-up, P = 0.01) and radial strain (baseline, P = 0.047; follow-up, P < 0.01), whilst LV longitudinal strain appeared comparable for both baseline and follow-up (P > 0.05 for both). In multi-variable regression analysis including all three strain directions, baseline LV circumferential strain was independently associated with the mean transmural extent score at follow-up (β=1.89, P < 0.001). In STEMI patients, time-to-reperfusion was significantly associated with smaller transmural extent of infarction and better LV circumferential and radial strain. Moreover, infarct transmurality and residual LV circumferential strain are closely linked.

Role of Cardiac Energetics in Aortic Stenosis Disease Progression: Identifying the High-risk Metabolic Phenotype.

Severe aortic stenosis (AS) is associated with left ventricular (LV) hypertrophy and cardiac metabolic alterations with evidence of steatosis and impaired myocardial energetics. Despite this common phenotype, there is an unexplained and wide individual heterogeneity in the degree of hypertrophy and progression to myocardial fibrosis and heart failure. We sought to determine whether the cardiac metabolic state may underpin this variability. We recruited 74 asymptomatic participants with AS and 13 healthy volunteers. Cardiac energetics were measured using phosphorus spectroscopy to define the myocardial phosphocreatine to adenosine triphosphate ratio. Myocardial lipid content was determined using proton spectroscopy. Cardiac function was assessed by cardiovascular magnetic resonance cine imaging. Phosphocreatine/adenosine triphosphate was reduced early and significantly across the LV wall thickness quartiles (Q2, 1.50 [1.21-1.71] versus Q1, 1.64 [1.53-1.94]) with a progressive decline with increasing disease severity (Q4, 1.48 [1.18-1.70]; P=0.02). Myocardial triglyceride content levels were overall higher in all the quartiles with a significant increase seen across the AV pressure gradient quartiles (Q2, 1.36 [0.86-1.98] versus Q1, 1.03 [0.81-1.56]; P=0.034). While all AS groups had evidence of subclinical LV dysfunction with impaired strain parameters, impaired systolic longitudinal strain was related to the degree of energetic impairment (r=0.219; P=0.03). Phosphocreatine/adenosine triphosphate was not only an independent predictor of LV wall thickness (r=-0.20; P=0.04) but also strongly associated with myocardial fibrosis (r=-0.24; P=0.03), suggesting that metabolic changes play a role in disease progression. The metabolic and functional parameters showed comparable results when graded by clinical severity of AS. A gradient of myocardial energetic deficit and steatosis exists across the spectrum of hypertrophied AS hearts, and these metabolic changes precede irreversible LV remodeling and subclinical dysfunction. As such, cardiac metabolism may play an important and potentially causal role in disease progression.

Deep learning-based prognostic model using non-enhanced cardiac cine MRI for outcome prediction in patients with heart failure.

To evaluate the performance of a deep learning-based multi-source model for survival prediction and risk stratification in patients with heart failure. Patients with heart failure with reduced ejection fraction (HFrEF) who underwent cardiac magnetic resonance between January 2015 and April 2020 were retrospectively included in this study. Baseline electronic health record data, including clinical demographic information, laboratory data, and electrocardiographic information, were collected. Short-axis non-contrast cine images of the whole heart were acquired to estimate the cardiac function parameters and the motion features of the left ventricle. Model accuracy was evaluated using the Harrell's concordance index. All patients were followed up for major adverse cardiac events (MACEs), and survival prediction was assessed using Kaplan-Meier curves. A total of 329 patients were evaluated (age 54 ± 14years; men, 254) in this study. During a median follow-up period of 1041days, 62 patients experienced MACEs and their median survival time was 495days. When compared with conventional Cox hazard prediction models, deep learning models showed better survival prediction performance. Multi-data denoising autoencoder (DAE) model reached the concordance index of 0.8546 (95% CI: 0.7902-0.8883). Furthermore, when divided into phenogroups, the multi-data DAE model could significantly discriminate between the survival outcomes of the high-risk and low-risk groups compared with other models (p < 0.001). The proposed deep learning (DL) model based on non-contrast cardiac cine magnetic resonance imaging could independently predict the outcome of patients with HFrEF and showed better prediction efficiency than conventional methods. The proposed multi-source deep learning model based on cardiac magnetic resonance enables survival prediction in patients with heart failure. • A multi-source deep learning model based on non-contrast cardiovascular magnetic resonance (CMR) cine images was built to make robust survival prediction in patients with heart failure. • The ground truth definition contains electronic health record data as well as DL-based motion data, and cardiac motion information is extracted by optical flow method from non-contrast CMR cine images. • The DL-based model exhibits better prognostic value and stratification performance when compared with conventional prediction models and could aid in the risk stratification in patients with HF.

C44 ATRIAL SEPTAL ABNORMALITIES: A CASE OF DOUBLE INTERATRIAL SEPTUM

Abstract The Case A 41–year–old asymptomatic male was referred to our cardiology outpatient clinic for diagnostic evaluation of a suspected bicuspid aortic valve at transthoracic echocardiography. Trans–oesophageal imaging ruled–out the bicuspid aortic valve, but detected an accessory membrane lining the interatrial septum with a double–layered appearance encompassing most of the fossa ovalis. Agitated saline infusion demonstrated an inter–atrial communication with right–to–left shunt under Valsalva manoeuvre. Cardiovascular magnetic resonance cine imaging confirmed the presence of a double interatrial septum featuring a midline recess enclosed by the two septa. Under end–expiratory breath–holding conditions, a transient right–to–left shunt was observed confirming the echocardiographic evaluation (Panel 1). No history of cerebrovascular disease and no clinical or imaging findings of right heart overload were registered. Discussion Double interatrial septum is a rare congenital condition, by morphological side, allegedly associated with an increased risk of left–sided embolic events due to blood stasis within the accessory interatrial chamber, that is often found in continuity with both atria through patent foramen ovale or additional septal fenestrations. In this case, multimodality imaging effectively was able to detect the presence of this rare atrial septal abnormality and to distinguish that from others alterations of the interatrial septum shown in the table below (Table 1). Nevertheless, the clinical significance of double interatrial septum remains uncertain, no clear relationship with embolic stroke is known and no recommendation can be made regarding the decision–making for long–term anti–thrombotic management. High quality evidences are needed to evaluate whether double atrial septum or other atrial septal abnormalities might be considered as actionable risk factors of ischemic stroke or not.

Coronary flow reserve evaluated by phase-contrast cine cardiovascular magnetic resonance imaging of coronary sinus: a meta-analysis

BackgroundPhase-contrast cine cardiovascular magnetic resonance (CMR) of the coronary sinus has emerged as a non-invasive method for measuring coronary sinus blood flow and coronary flow reserve (CFR). However, its clinical utility has not yet been established. Here we performed a meta-analysis to clarify the clinical value of CMR-derived CFR in various cardiovascular diseases. MethodsAn electronic database search was performed of PubMed, Web of Science Core Collection, Cochrane Advanced Search, and EMBASE. We compared the CMR-derived CFR of various cardiovascular diseases (stable coronary artery disease [CAD], hypertrophic cardiomyopathy [HCM], dilated cardiomyopathy [DCM]) and control subjects. We assessed the prognostic value of CMR-derived CFR for predicting major adverse cardiac events (MACE) in patients with stable CAD. ResultsA total of 47 eligible studies were identified. The pooled CFR from our meta-analysis was 3.48 (95% confidence interval [CI], 2.98–3.98) in control subjects, 2.50 (95% CI, 2.38–2.61) in stable CAD, 2.01 (95% CI, 1.70–2.32) in cardiomyopathies (HCM and DCM). The meta-analysis showed that CFR was significantly reduced in stable CAD (mean difference [MD] = −1.48; 95% CI, −1.78 to −1.17; p < 0.001; I2 = 0%; p for heterogeneity = 0.33), HCM (MD = −1.20; 95% CI, −1.63 to −0.77; p < 0.001; I2 = 0%; p for heterogeneity = 0.49), and DCM (MD = −1.53; 95% CI, −1.93 to −1.13; p < 0.001; I2 = 0%; p for heterogeneity = 0.45). CMR-derived CFR was an independent predictor of MACE for patients with stable CAD (hazard ratio = 0.52 per unit increase; 95% CI, 0.37–0.73; p < 0.001; I2 = 84%, p for heterogeneity < 0.001). ConclusionsCMR-derived CFR was significantly decreased in cardiovascular diseases, and a decreased CFR was associated with a higher occurrence of MACE in patients with stable CAD. These results suggest that CMR-derived CFR has potential for the pathological evaluation of stable CAD, cardiomyopathy, and risk stratification in CAD.

Localized strain characterization of cardiomyopathy in Duchenne muscular dystrophy using novel 4D kinematic analysis of cine cardiovascular magnetic resonance

BackgroundCardiomyopathy (CMP) is the most common cause of mortality in Duchenne muscular dystrophy (DMD), though the age of onset and clinical progression vary. We applied a novel 4D (3D + time) strain analysis method using cine cardiovascular magnetic resonance (CMR) imaging data to determine if localized strain metrics derived from 4D image analysis would be sensitive and specific for characterizing DMD CMP. MethodsWe analyzed short-axis cine CMR image stacks from 43 DMD patients (median age: 12.23 yrs [10.6–16.5]; [interquartile range]) and 25 male healthy controls (median age: 16.2 yrs [13.3–20.7]). A subset of 25 male DMD patients age-matched to the controls (median age: 15.7 yrs [14.0-17.8]) was used for comparative metrics. CMR images were compiled into 4D sequences for feature-tracking strain analysis using custom-built software. Unpaired t-test and receiver operator characteristic area under the curve (AUC) analysis were used to determine statistical significance. Spearman's rho was used to determine correlation. ResultsDMD patients had a range of CMP severity: 15 (35% of total) had left ventricular ejection fraction (LVEF) > 55% with no findings of myocardial late gadolinium enhancement (LGE), 15 (35%) had findings of LGE with LVEF > 55% and 13 (30%) had LGE with LVEF < 55%. The magnitude of the peak basal circumferential strain, basal radial strain, and basal surface area strain were all significantly decreased in DMD patients relative to healthy controls (p < 0.001) with AUC values of 0.80, 0.89, and 0.84 respectively for peak strain and 0.96, 0.91, and 0.98 respectively for systolic strain rate. Peak basal radial strain, basal radial systolic strain rate, and basal circumferential systolic strain rate magnitude values were also significantly decreased in mild CMP (No LGE, LVEF > 55%) compared to a healthy control group (p< 0.001 for all). Surface area strain significantly correlated with LVEF and extracellular volume (ECV) respectively in the basal (rho = − 0.45, 0.40), mid (rho = − 0.46, 0.46), and apical (rho = − 0.42, 0.47) regions. ConclusionStrain analysis of 3D cine CMR images in DMD CMP patients generates localized kinematic parameters that strongly differentiate disease from control and correlate with LVEF and ECV.

The use of dedicated long-axis views focused on the left atrium improves the accuracy of left atrial volumes and emptying fraction measured by cardiovascular magnetic resonance

BackgroundThe use of apical views focused on the left atrium (LA) has improved the accuracy of LA volume evaluation by two-dimensional (2D) echocardiography. However, routine cardiovascular magnetic resonance (CMR) evaluation of LA volumes still uses standard 2- and 4-chamber cine images focused on the left ventricle (LV). To investigate the potential of LA-focused CMR cine images, we compared LA maximuml (LAVmax) and minimum (LAVmin) volumes, and emptying fraction (LAEF), calculated on both standard and LA-focused long-axis cine images, with LA volumes and LAEF obtained by short-axis cine stacks covering the LA. LA strain was also calculated and compared between standard and LA-focused images. MethodsLA volumes and LAEF were obtained from 108 consecutive patients by applying the biplane area-length algorithm to both standard and LA-focused 2- and 4-chamber cine images. Manual segmentation of a short-axis cine stack covering the LA was used as the reference method. In addition, LA strain reservoir (εs), conduit (εe) and booster pump (εa) were calculated using CMR feature-tracking. ResultsCompared to the reference method, the standard approach significantly underestimated LA volumes (LAVmax: bias − 13 ml; LOA = + 11, − 37 ml; LAVmax i: bias − 7 ml/m2; LOA = + 7, − 21 ml/m2; LAVmin; bias − 10 ml, LOA: + 9, − 28 ml; LAVmin i: bias − 5 ml/m2, LOA: + 5, − 16 ml/m2), and overestimated LA-EF (bias 5%, LOA: + 23, − 14%). Conversely, LA volumes (LAVmax: bias 0 ml; LOA: + 10, − 10 ml; LAVmax i: bias 0 ml/m2; LOA: + 5, − 6 ml/m2; LAVmin: bias − 2 ml; LOA: + 7, − 10 ml; LAVmin i: bias − 1 ml/m2; LOA: + 3, − 5 ml/m2) and LAEF (bias 2%, LOA: + 11, − 7%) by LA-focused cine images were similar to those measured using the reference method. LA volumes by LA-focused images were obtained faster than using the reference method (1.2 vs 4.5 min, p < 0.001). LA strain (εs: bias 7%, LOA = 25, − 11%; εe: bias 4%, LOA = 15, − 8%; εa: bias 3%, LOA = 14, − 8%) was significantly higher in standard vs. LA-focused images (p < 0.001). ConclusionLA volumes and LAEF measured using dedicated LA-focused long-axis cine images are more accurate than using standard LV-focused cine images. Moreover, LA strain is significantly lower in LA-focused vs. standard images.

Prognostic implications of trabecular complexity measured by fractal analysis in left ventricular noncompaction

Abstract Introduction Left ventricular non compaction (LVNC) is a heterogeneous entity characterized by prominent LV trabeculae. Fractal analysis, a semi-automatic method to quantify the degree of hypertrabeculation, has been described as a diagnostic criterion for LVNC. However, the prognostic implications of fractal analysis have not been investigated. Purpose Therefore, the aim of our study was to identify the relationship between the trabecular complexity measured by fractal analysis and the occurrence of cardiovascular events in LVNC patients. Methods We conducted a retrospective longitudinal multicenter cohort study of consecutive patients fulfilling LVNC criteria by cardiovascular magnetic resonance (CMR). The endpoints were heart failure (HF), ventricular arrythmias (VA), systemic embolism (SE) and all-cause mortality. Fractal analysis was performed on short-axis CMR cine images using CVI 42 software. The cohort was divided in two groups according to the maximal apical fractal dimension (FD). Results A total of 291 patients were included: age was 44±19 years and 56% were female. LV ejection fraction (LVEF) was 47% ± 14% and 26 patients (9%) presented late gadolinium enhancement (LGE). Mean global FD was 1.29±0.06 and maximal apical FD was 1.39±0.09. Baseline characteristics of patients with maximal apical FD 1.39 and 1.39, including functional LV parameters, were comparable (Table 1). After 3.8±2.5 years of follow-up, 37 patients (12.8%) presented HF, 30 (10.4%) had VA, SE occurred in 3 (1%) and 3 patients (1%) died. Maximal apical FD was not associated with the risk of HF or VA (both p ns), nor was mean global FD. There were no significant differences in the survival curves of both endpoints between the two groups: HR were 2.34 (95% CI 0.74–7.4, p 0.13) and 1.15 (95% CI 0.45–2.41, p 0.71) respectively for HF and VA (Image 1). LVEF and LGE remained consistent predictors of events. Conclusions In a large multicenter retrospective LVNC study, the degree of hypertrabeculation measured by fractal analysis was not associated with functional LV parameters and, most importantly, with the incidence of cardiovascular events. Therefore, our results suggest that diagnostic LVNC criteria should be refined to include parameters with actual prognostic implications. Funding Acknowledgement Type of funding sources: None.

Invasive validation of pressure-volume loops derived from cardiovascular magnetic resonance imaging and brachial blood pressure in heart failure patients

Abstract Introduction Left ventricular (LV) pressure-volume (PV) loops provide gold-standard physiological information but require invasive measurements of ventricular intracavity pressure, limiting clinical and research applications. Recent development has seen the introduction of non-invasively computed PV loops from cardiovascular magnetic resonance (CMR) volumetry and a brachial blood pressure measurement. The approach combines LV volumes with a time-varying elastance function to compute time-resolved LV pressures and was validated on invasive pressure data from a porcine model. The method is readily implemented using standard CMR sequences and provides measures of hemodynamic parameters including stroke work, myocardial efficiency, and contractile state. However, the method remains to be validated in patients using invasive left ventricular pressure recordings. Purpose To validate for the first time in human patients the performance of non-invasively computed PV loops against invasive measures. Methods Four heart failure patients underwent two subsequent sessions of CMR cine imaging and simultaneous brachial blood pressure measurement, with intravenous administration of two different vasoactive drugs, resulting in two different haemodynamic states for each patient. LV catheterization was then conducted with repeat administration of the same infusions. Pressure-volume loops were computed from CMR volumes combined with 1) a time-varying elastance function scaled to brachial blood pressure and temporally stretched to match volume data, and 2) invasive pressures averaged from multiple sampled beats. Method comparison was conducted using linear regression and Bland-Altman analysis. Results Figure 1 shows non-invasively derived PV loop parameters compared to invasive data. The non-invasive method demonstrated strong correlations and low bias for stroke work (R2=0.97, bias 4.6%, p&amp;lt;0.0001), potential energy (R2=0.83, bias 1.5%, p=0.001), end-systolic pressure-volume relationship (R2=0.90, bias 5.4%, p=0.0003), energy per ejected volume (R2=0.93, bias 3.5%, p=0.0001), ventricular efficiency (R2=0.99, bias 1.1%, p&amp;lt;0.0001), arterial elastance (R2=0.87, bias −7.8%, p=0.0006), and mean external power (R2=0.89, bias 4.6%, p=0.0005). Conclusions Pressure-volume loops can be precisely and accurately computed from cardiovascular magnetic resonance imaging and brachial cuff blood pressure in humans, and is ready for use in research applications. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Swedish Heart Lung Foundation

Normative healthy reference values for global and segmental 3D principal and geometry dependent strain from cine cardiac magnetic resonance imaging.

3-Dimensional (3D) myocardial deformation analysis (3D-MDA) enables novel descriptions of geometry-independent principal strain (PS). Applied to routine 2D cine cardiovascular magnetic resonance (CMR), this provides unique measures of myocardial biomechanics for disease diagnosis and prognostication. However, healthy reference values remain undefined. This study describes age- and sex-stratified reference values from CMR-based 3D-MDA, including 3D PS. One hundred healthy volunteers were prospectively recruited following institutional ethics approval and underwent CMR imaging. 3D-MDA was performed using validated software. Age- and sex-stratified global and segmental strain measures were derived for conventional geometry-dependent [circumferential (CS), longitudinal (LS), and radial (RS)] and geometry-independent [minimum (minPS) and maximum principal (maxPS)] directions of deformation. Layer-specific contraction angle interactions were determined using local minPS vectors. The average age was 43 ± 15years and 55% were women. Strain measures were higher in women versus men. 3D PS-based assessment of maximum tissue shortening (minPS) and maximum tissue thickening (maxPS) were greater than corresponding geometry-dependent markers of LS and RS, consistent with improved representation of local tissue deformations. Global maxPS amplitude best discriminated both age and sex. Segmental analyses showed greater strain amplitudes in apical segments. Transmural PS contraction angles were higher in females and showed a heterogeneous distribution across segments. In this study we provided age and sex-based reference values for 3D strain from CMR imaging, demonstrating improved capacity for 3D PS to document maximal local tissue deformations and to discriminate age and sex phenotypes. Novel markers of layer-specific strain angles from 3D PS were also described.

Assessment of Bi-Ventricular and Bi-Atrial Areas Using Four-Chamber Cine Cardiovascular Magnetic Resonance Imaging: Fully Automated Segmentation with a U-Net Convolutional Neural Network.

Four-chamber (4CH) cine cardiovascular magnetic resonance imaging (CMR) facilitates simultaneous evaluation of cardiac chambers; however, manual segmentation is time-consuming and subjective in practice. We evaluated deep learning based on a U-Net convolutional neural network (CNN) for fully automated segmentation of the four cardiac chambers using 4CH cine CMR. Cine CMR datasets from patients were randomly assigned for training (1400 images from 70 patients), validation (600 images from 30 patients), and testing (1000 images from 50 patients). We validated manual and automated segmentation based on the U-Net CNN using the dice similarity coefficient (DSC) and Spearman’s rank correlation coefficient (ρ); p < 0.05 was statistically significant. The overall median DSC showed high similarity (0.89). Automated segmentation correlated strongly with manual segmentation in all chambers—the left and right ventricles, and the left and right atria (end-diastolic area: ρ = 0.88, 0.76, 0.92, and 0.87; end-systolic area: ρ = 0.81, 0.81, 0.92, and 0.83, respectively; p < 0.01). The area under the curve for the left ventricle, left atrium, right ventricle, and right atrium showed high scores (0.96, 0.99, 0.88, and 0.96, respectively). Fully automated segmentation could facilitate simultaneous evaluation and detection of enlargement of the four cardiac chambers without any time-consuming analysis.

Acute intra-cavity 4D flow cardiovascular magnetic resonance predicts long-term adverse remodelling following ST-elevation myocardial infarction

BackgroundDespite advancements in percutaneous coronary intervention, a significant proportion of ST-elevation myocardial infarction (STEMI) survivors develop long-term adverse left ventricular (LV) remodelling, which is associated with poor prognosis. Adverse remodelling is difficult to predict, however four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) can measure various aspects of LV intra-cavity flow beyond LV ejection fraction and is well equipped for exploring the underlying mechanical processes driving remodelling. The aim for this study was to compare acute 4D flow CMR parameters between patients who develop adverse remodelling with patients who do not.MethodsFifty prospective ‘first-event’ STEMI patients underwent CMR 5 days post-reperfusion, which included cine-imaging, and 4D flow for assessing in-plane kinetic energy (KE), residual volume, peak-E and peak-A wave KE (indexed for LV end-diastolic volume [LVEDV]). All subjects underwent follow-up cine CMR imaging at 12 months to identify adverse remodelling (defined as 20% increase in LVEDV from baseline). Quantitative variables were compared using unpaired student’s t-test. Tests were deemed statistically significant when p < 0.05.ResultsPatients who developed adverse LV remodelling by 12 months had significantly higher in-plane KE (54 ± 12 vs 42 ± 10%, p = 0.02), decreased proportion of direct flow (27 ± 9% vs 11 ± 4%, p < 0.01), increased proportion of delayed ejection flow (22 ± 9% vs 12 ± 2, p < 0.01) and increased proportion of residual volume after 2 consecutive cardiac cycles (64 ± 14 vs 34 ± 14%, p < 0.01), in their acute scan.ConclusionFollowing STEMI, increased in-plane KE, reduced direct flow and increased residual volume in the acute scan were all associated with adverse LV remodelling at 12 months. Our results highlight the clinical utility of acute 4D flow in prognostic stratification in patients following myocardial infarction.

Clinical Evaluation of Left Ventricular Diastolic Function Using Phase-contrast Cine Cardiovascular Magnetic Resonance Imaging: A Comparison With Steady-state Free Precession Cine Cardiovascular Magnetic Resonance Imaging and Echocardiography.

We investigated a practical method using phase-contrast (PC) cine cardiovascular magnetic resonance imaging to estimate peak filling rate and early/atrial velocity (E/A) as left ventricular diastolic function indicators. Peak filling rate and E/A were estimated in 32 patients using PC imaging with high spatial or high temporal resolution and compared with those estimated using steady-state free precession cine cardiovascular magnetic resonance imaging and echocardiography. Peak filling rate estimated using PC imaging significantly correlated with those estimated using steady-state free precession imaging despite apparent underestimation using PC imaging with high spatial resolution. The E/A estimated using PC imaging significantly correlated with those estimated using echocardiography. Peak filling rate and E/A measurements using PC imaging with high temporal resolution is convenient and acceptably accurate, suggesting its potential for clinical use.

Energetic Basis for Exercise-Induced Pulmonary Congestion in Heart Failure With Preserved Ejection Fraction.

Transient pulmonary congestion during exercise is emerging as an important determinant of reduced exercise capacity in heart failure with preserved ejection fraction (HFpEF). We sought to determine whether an abnormal cardiac energetic state underpins this process. We recruited patients across the spectrum of diastolic dysfunction and HFpEF (controls, n=11; type 2 diabetes, n=9; HFpEF, n=14; and severe diastolic dysfunction attributable to cardiac amyloidosis, n=9). Cardiac energetics were measured using phosphorus spectroscopy to define the myocardial phosphocreatine to ATP ratio. Cardiac function was assessed by cardiovascular magnetic resonance cine imaging and echocardiography and lung water using magnetic resonance proton density mapping. Studies were performed at rest and during submaximal exercise using a magnetic resonance imaging ergometer. Paralleling the stepwise decline in diastolic function across the groups (E/e' ratio; P<0.001) was an increase in NT-proBNP (N-terminal pro-brain natriuretic peptide; P<0.001) and a reduction in phosphocreatine/ATP ratio (control, 2.15 [2.09, 2.29]; type 2 diabetes, 1.71 [1.61, 1.91]; HFpEF, 1.66 [1.44, 1.89]; cardiac amyloidosis, 1.30 [1.16, 1.53]; P<0.001). During 20-W exercise, lower left ventricular diastolic filling rates (r=0.58; P<0.001), lower left ventricular diastolic reserve (r=0.55; P<0.001), left atrial dilatation (r=-0.52; P<0.001), lower right ventricular contractile reserve (right ventricular ejection fraction change, r=0.57; P<0.001), and right atrial dilation (r=-0.71; P<0.001) were all linked to lower phosphocreatine/ATP ratio. Along with these changes, pulmonary proton density mapping revealed transient pulmonary congestion in patients with HFpEF (+4.4% [0.5, 6.4]; P=0.002) and cardiac amyloidosis (+6.4% [3.3, 10.0]; P=0.004), which was not seen in healthy controls (-0.1% [-1.9, 2.1]; P=0.89) or type 2 diabetes without HFpEF (+0.8% [-1.7, 1.9]; P=0.82). The development of exercise-induced pulmonary congestion was associated with lower phosphocreatine/ATP ratio (r=-0.43; P=0.004). A gradient of myocardial energetic deficit exists across the spectrum of HFpEF. Even at low workload, this energetic deficit is related to markedly abnormal exercise responses in all 4 cardiac chambers, which is associated with detectable pulmonary congestion. The findings support an energetic basis for transient pulmonary congestion in HFpEF.

Left ventricular function, strain, and infarct characteristics in patients with transient ST-segment elevation myocardial infarction compared to ST-segment and non-ST-segment elevation myocardial infarctions.

AimsThis study aims to explore cardiovascular magnetic resonance (CMR)-derived left ventricular (LV) function, strain, and infarct size characteristics in patients with transient ST-segment elevation myocardial infarction (TSTEMI) compared to patients with ST-segment and non-ST-segment elevation myocardial infarctions (STEMI and NSTEMI, respectively).Methods and resultsIn total, 407 patients were enrolled in this multicentre observational prospective cohort study. All patients underwent CMR examination 2–8 days after the index event. CMR cine imaging was performed for functional assessment and late gadolinium enhancement to determine infarct size and identify microvascular obstruction (MVO). TSTEMI patients demonstrated the highest LV ejection fraction and the most preserved global LV strain (longitudinal, circumferential, and radial) across the three groups (overall P ≤ 0.001). The CMR-defined infarction was less frequently observed in TSTEMI than in STEMI patients [77 (65%) vs. 124 (98%), P < 0.001] but was comparable with NSTEMI patients [77 (65%) vs. 66 (70%), P = 0.44]. A remarkably smaller infarct size was seen in TSTEMI compared to STEMI patients [1.4 g (0.0–3.9) vs. 13.5 g (5.3–26.8), P < 0.001], whereas infarct size was not significantly different from that in NSTEMI patients [1.4 g (0.0–3.9) vs. 2.1 g (0.0–8.6), P = 0.06]. Whilst the presence of MVO was less frequent in TSTEMI compared to STEMI patients [5 (4%) vs. 53 (31%), P < 0.001], no significant difference was seen compared to NSTEMI patients [5 (4%) vs. 5 (5%), P = 0.72].ConclusionTSTEMI yielded favourable cardiac LV function, strain, and infarct-related scar mass compared to STEMI and NSTEMI. LV function and infarct characteristics of TSTEMI tend to be more similar to NSTEMI than STEMI.