Cardiac Magnetic Resonance Techniques Research Articles

Excessive accumulation of epicardial adipose tissue promotes microvascular obstruction formation after myocardial ischemia/reperfusion through modulating macrophages polarization

BackgroundOwing to its unique location and multifaceted metabolic functions, epicardial adipose tissue (EAT) is gradually emerging as a new metabolic target for coronary artery disease risk stratification. Microvascular obstruction (MVO) has been recognized as an independent risk factor for unfavorable prognosis in acute myocardial infarction patients. However, the concrete role of EAT in the pathogenesis of MVO formation in individuals with ST-segment elevation myocardial infarction (STEMI) remains unclear. The objective of the study is to evaluate the correlation between EAT accumulation and MVO formation measured by cardiac magnetic resonance (CMR) in STEMI patients and clarify the underlying mechanisms involved in this relationship.MethodsFirstly, we utilized CMR technique to explore the association of EAT distribution and quantity with MVO formation in patients with STEMI. Then we utilized a mouse model with EAT depletion to explore how EAT affected MVO formation under the circumstances of myocardial ischemia/reperfusion (I/R) injury. We further investigated the immunomodulatory effect of EAT on macrophages through co-culture experiments. Finally, we searched for new therapeutic strategies targeting EAT to prevent MVO formation.ResultsThe increase of left atrioventricular EAT mass index was independently associated with MVO formation. We also found that increased circulating levels of DPP4 and high DPP4 activity seemed to be associated with EAT increase. EAT accumulation acted as a pro-inflammatory mediator boosting the transition of macrophages towards inflammatory phenotype in myocardial I/R injury through secreting inflammatory EVs. Furthermore, our study declared the potential therapeutic effects of GLP-1 receptor agonist and GLP-1/GLP-2 receptor dual agonist for MVO prevention were at least partially ascribed to its impact on EAT modulation.ConclusionsOur work for the first time demonstrated that excessive accumulation of EAT promoted MVO formation by promoting the polarization state of cardiac macrophages towards an inflammatory phenotype. Furthermore, this study identified a very promising therapeutic strategy, GLP-1/GLP-2 receptor dual agonist, targeting EAT for MVO prevention following myocardial I/R injury.

Advances in multimodality imaging and the application of new cardiac imaging technologies for radiation‐induced heart disease

AbstractRadiation‐induced heart disease (RIHD) is a heterogeneous, delayed, and potentially fatal adverse reaction to radiation that can damage all structures of the heart, including the pericardium, myocardium, coronary arteries, valves, and conduction system, leading to a series of diseases. Acute and chronic disease processes play a role in the development of RIHD, the onset times of which range from months to decades. However, the clinical manifestations of RIHD are usually insidious, overlap with several other diseases, and lack specificity. Cardiovascular imaging is essential for early diagnosis, follow‐up, and outcome assessment in patients with RIHD. This review first describes the pathogenesis and clinical manifestations of RIHD before providing an overview of the practical approaches and research advances in multimodal cardiovascular imaging in patients with RIHD, including echocardiography, cardiac magnetic resonance (CMR) and nuclear medicine, and cardiac computed tomography (CT). Then, the value of new cardiac imaging assessments for the early diagnosis of RIHD is described, particularly with relation to speckle‐tracking echocardiography, extracellular volume fraction assessment as a quantitative CMR technique, CMR myocardial strain assessment, positron emission tomography‐CT myocardial perfusion imaging, CT‐ECV, and CT strain assessment, amongst others. In addition, the advantages and disadvantages of each screening technique are compared with the aim of better guiding the follow‐up and diagnosis of subclinical RIHD and preventing cardiovascular events.

Assessing Regurgitation Severity, Adverse Remodeling, and Fibrosis with CMR in Aortic Regurgitation.

Cardiac magnetic resonance (CMR) is emerging as a valuable imaging modality for the assessment of aortic regurgitation (AR). In this review, we discuss the assessment of AR severity, left ventricular (LV) remodeling, and tissue characterization by CMR while highlighting the latest studies and addressing future research needs. Recent studies have further established CMR-based thresholds of AR severity and LV remodeling that are associated with adverse clinical outcomes, and lower than current guideline criteria. In addition, tissue profiling with late gadolinium enhancement (LGE) and extracellular volume (ECV) quantification can reliably assess adverse myocardial tissue remodeling which is also associated with adverse outcomes. The strengths and reproducibility of CMR in evaluating ventricular volumes, tissue characteristics, and regurgitation severity position it as an excellent modality in evaluating and following AR patients. Advanced CMR techniques for the detection of tissue remodeling have shown significant potential and merit further investigation.

Early detection of myocardial involvement by non-contrast T1ρ mapping of cardiac magnetic resonance in type 2 diabetes mellitus.

This study aims to determine the effectiveness of T1ρ in detecting myocardial fibrosis in type 2 diabetes mellitus (T2DM) patients by comparing with native T1 and extracellular volume (ECV) fraction. T2DM patients (n = 35) and healthy controls (n = 30) underwent cardiac magnetic resonance. ECV, T1ρ, native T1, and global longitudinal strain (GLS) values were assessed. Diagnostic performance was analyzed using receiver operating curves. The global ECV and T1ρ of T2DM group (ECV = 32.1 ± 3.2%, T1ρ = 51.6 ± 3.8 msec) were significantly higher than those of controls (ECV = 26.2 ± 1.6%, T1ρ = 46.8 ± 2.0 msec) (all P < 0.001), whether there was no significant difference in native T1 between T2DM and controls (P = 0.264). The GLS decreased significantly in T2DM patients compared with controls (-16.5 ± 2.4% vs. -18.3 ± 2.6%, P = 0.015). The T1ρ and native T1 were associated with ECV (Pearson's r = 0.50 and 0.25, respectively, both P < 0.001); the native T1, T1ρ, and ECV were associated with hemoglobin A1c (Pearson's r = 0.41, 0.52, and 0.61, respectively, all P < 0.05); and the ECV was associated with diabetes duration (Pearson's r = 0.41, P = 0.016). The AUC of ECV, T1ρ, GLS, and native T1 were 0.869, 0.810, 0.659, and 0.524, respectively. In T2DM patients, T1ρ may be a new non-contrast cardiac magnetic resonance technique for identifying myocardial diffuse fibrosis, and T1ρ may be more sensitive than native T1 in the detection of myocardial diffuse fibrosis.

Abstract 15036: Identification of Fabry Disease Cardiac Phenotype in Hypertrophic Cardiomyopathy With Cardiac Magnetic Resonance Imaging Technology

Introduction: Cardiac magnetic resonance(CMR), especially T1 mapping, has an important role in the diagnosis of Fabry disease, but the differential value in myocardial diseases with hypertrophic phenotype needs further study. More importantly, there has been no systematic study of the difference between different CMR techniques indistinguishing Fabry cardiomyopathy from hypertrophic cardiomyopathy (HCM). Hypothesis: Myomapping technology can be a parameter in distinguishing Fabry cardiomyopathy from HCM. Methods: We continuously included patients with clinically diagnosed hypertrophic cardiomyopathy, completed systematic magnetic resonance imaging, and used genetic testing as the diagnostic criteria. We reported the prevalence rate in the population of HCM, and deeply conducted comparative studies on the differences in magnetic resonance characteristics between Fabry disease and HCM. We also analyzed the diagnostic value of magnetic resonance imaging in distinguishing Fabry cardiomyopathy from HCM. Results: We continuously included patients diagnosed with hypertrophic cardiomyopathy at West China Hospital from 2012 to 2022 and completed systematic magnetic resonance imaging examinations. We reported the prevalence of Fabry cardiomyopathy in the population using genetic testing as the diagnostic criteria, and deeply conducted comparative studies on the differences in CMR features between Fabry disease and HCM. We also analyzed the diagnostic value of CMR in distinguishing Fabry cardiomyopathy from HCM. Conclusions: We found a prevalence of 13 (2.6%) cases of Fabry disease in the hypertrophic cardiomyopathy cohort (494 cases). Our further analysis found that there were no significant differences in the degree of hypertrophy, overall cardiac function and size of Fabry patients compared with patients with HCM, as well as strain analysis. NativeT1 was significantly reduced in Fabry disease, and segmental analysis found that the basal and middle ventricular septum and anterior wall were the most obvious. ECV differed significantly between the two groups. There was no difference in T2 between the two groups. ROC analysis showed that T1 had the most discriminating value

Contrast-enhanced cardiac MRI is superior to non-contrast mapping to predict left ventricular remodeling at 6 months after acute myocardial infarction

ObjectivesParametric mapping constitutes a novel cardiac magnetic resonance (CMR) technique enabling quantitative assessment of pathologic alterations of left ventricular (LV) myocardium. This study aimed to investigate the clinical utility of mapping techniques with and without contrast agent compared to standard CMR to predict adverse LV remodeling following acute myocardial infarction (AMI).Materials and methodsA post hoc analysis was performed on sixty-four consecutively enrolled patients (57 ± 12 years, 54 men) with first-time reperfused AMI. Baseline CMR was obtained at 8 ± 5 days post-AMI, and follow-up CMR at 6 ± 1.4 months. T1/T2 mapping, T2-weighted, and late gadolinium enhancement (LGE) acquisitions were performed at baseline and cine imaging was used to determine adverse LV remodeling, defined as end-diastolic volume increase by 20% at 6 months.ResultsA total of 11 (17%) patients developed adverse LV remodeling. At baseline, patients with LV remodeling showed larger edema (30 ± 11 vs. 22 ± 10%LV; p < 0.05), infarct size (24 ± 11 vs. 14 ± 8%LV; p < 0.001), extracellular volume (ECVinfarct; 63 ± 12 vs. 47 ± 11%; p < 0.001), and native T2infarct (95 ± 16 vs. 78 ± 17 ms; p < 0.01). ECVinfarct and infarct size by LGE were the best predictors of LV remodeling with areas under the curve (AUCs) of 0.843 and 0.789, respectively (all p < 0.01). Native T1infarct had the lowest AUC of 0.549 (p = 0.668) and was inferior to edema size by T2-weighted imaging (AUC = 0.720; p < 0.05) and native T2infarct (AUC = 0.766; p < 0.01).ConclusionIn this study, ECVinfarct and infarct size by LGE were the best predictors for the development of LV remodeling within 6 months after AMI, with a better discriminative performance than non-contrast mapping CMR.Clinical relevance statementThis study demonstrates the predictive value of contrast-enhanced and non-contrast as well as conventional and novel CMR techniques for the development of LV remodeling following AMI, which might help define precise CMR endpoints in experimental and clinical myocardial infarction trials.Key Points• Multiparametric CMR provides insights into left ventricular remodeling at 6 months following an acute myocardial infarction.• Extracellular volume fraction and infarct size are the best predictors for adverse left ventricular remodeling.• Contrast-enhanced T1 mapping has a better predictive performance than non-contrast standard CMR and T1/T2 mapping.

Advanced CMR Techniques in Anderson-Fabry Disease: State of the Art.

Anderson-Fabry disease (AFD) is a rare multisystem X-linked lysosomal storage disorder caused by α-galactosidase A enzyme deficiency. Long-term cardiac involvement in AFD results in left ventricular hypertrophy and myocardial fibrosis, inducing several complications, mainly arrhythmias, valvular dysfunction, and coronary artery disease. Cardiac magnetic resonance (CMR) represents the predominant noninvasive imaging modality for the assessment of cardiac involvement in the AFD, being able to comprehensively assess cardiac regional anatomy, ventricular function as well as to provide tissue characterization. This review aims to explore the role of the most advanced CMR techniques, such as myocardial strain, T1 and T2 mapping, perfusion and hybrid imaging, as diagnostic and prognostic biomarkers.

Differentiation of acute non-ST elevation myocardial infarction and acute infarct-like myocarditis by visual pattern analysis: a head-to-head comparison of different cardiac MR techniques

ObjectivesParametric cardiac magnetic resonance (CMR) techniques have improved the diagnosis of pathologies. However, the primary tool for differentiating non-ST elevation myocardial infarction (NSTEMI) from myocarditis is still a visual assessment of conventional signal-intensity-based images. This study aimed at analyzing the ability of parametric compared to conventional techniques to visually differentiate ischemic from non-ischemic myocardial injury patterns.MethodsTwenty NSTEMI patients, twenty infarct-like myocarditis patients, and twenty controls were examined using cine, T2-weighted CMR (T2w) and late gadolinium enhancement (LGE) imaging and T1/T2 mapping on a 1.5 T scanner. CMR images were presented in random order to two experienced fully blinded observers, who had to assign them to three categories by a visual analysis: NSTEMI, myocarditis, or healthy.ResultsThe conventional approach (cine, T2w and LGE combined) had the best diagnostic accuracy with 92% (95%CI: 81–97) for NSTEMI and 86% (95%CI: 71–94) for myocarditis. The diagnostic accuracies using T1 maps were 88% (95%CI: 74–95) and 80% (95%CI: 62–91), 84% (95%CI: 67–93) and 74% (95%CI: 54–87) for LGE, and 83% (95%CI: 66–92) and 73% (95%CI: 53–87) for T2w. The accuracies for cine (72% (95%CI: 52–86) and 60% (95%CI: 38–78)) and T2 maps (62% (95%CI: 40–79) and 47% (95%CI: 28–68)) were significantly lower compared to the conventional approach (p < 0.001 and p < 0.0001).ConclusionsThe conventional approach provided a reliable visual discrimination between NSTEMI, myocarditis, and controls. The diagnostic accuracy of a visual pattern analysis of T1 maps was not significantly inferior, whereas the diagnostic accuracy of T2 maps was not sufficient in this context.Clinical relevance statementThe ability of parametric compared to conventional CMR techniques to visually differentiate ischemic from non-ischemic myocardial injury patterns can avoid potentially unnecessary invasive coronary angiography and help to shorten CMR protocols and to reduce the need of gadolinium contrast agents.Key Points•A visual differentiation of ischemic from non-ischemic patterns of myocardial injury is reliably achieved by a combination of conventional CMR techniques (cine, T2-weighted and LGE imaging).•There is no significant difference in accuracies between visual pattern analysis on native T1 maps without providing quantitative values and a conventional combined approach for differentiating non-ST elevation myocardial infarction, infarct-like myocarditis, and controls.•T2 maps do not provide a sufficient diagnostic accuracy for visual pattern analysis for differentiating non-ST elevation myocardial infarction, infarct-like myocarditis, and controls.

The prognostic value of myocardial salvage index by cardiac magnetic resonance in ST-segment elevation myocardial infarction patients: a systematic review and meta-analysis.

To assess the prognostic value of myocardial salvage index (MSI) by cardiac magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients. We systematically searched PubMed, Embase, Web of Science, Cochrane Central, China National Knowledge Infrastructure, and Wanfang Data to identify primary studies reporting MSI in STEMI patients with major adverse cardiovascular events (MACE) comprised of death, myocardial reinfarction, and congestive heart failure. The MSI and MACE rates were pooled. The bias of risk was assessed using the Quality In Prognosis Studies tool. The evidence level was rated based on the meta-analysis of hazard ratio (HR) and 95% confidence interval (CI) of MSI for predicting MACE. Eighteen studies were included covering twelve unique cohorts. Eleven cohorts measured MSI using T2-weighted imaging and T1-weighted late gadolinium enhancement, while one cohort applied T2-mapping and T1-mapping. The pooled MSI (95% CI) was 44% (39 to 49%; 11 studies, 2946 patients), and the pooled MACE rate (95% CI) was 10% (7 to 14%; 12 studies, 311/3011 events/patients). Seven prognostic studies overall showed low risk of bias. The HR (95% CI) per 1% increase of MSI for MACE was 0.95 (0.92 to 0.98; 5 studies, 150/885 events/patients), and HR (95% CI) of MSI < median versus MSI > median for MACE was 5.62 (3.74 to 8.43; 6 studies, 166/1570 events/patients), both rated as weak evidence. MSI presents potential in predicting MACE in STEMI patients. The prognostic value of MSI using advanced CMR techniques for adverse cardiovascular events needs further investigation. Seven studies supported the MSI to serve as a predictor for MACE in STEMI patients, indicating its potential as a risk stratification tool to help manage expectations for these patients in clinical practice. • The pooled infarct size (95% CI) and area at risk (95% CI) were 21% (18 to 23%; 11 studies, 2783 patients) and 38% (34 to 43%; 10 studies, 2022 patients), respectively. • The pooled rates (95% CI) of cardiac mortality, myocardial reinfarction, and congestive heart failure were 2% (1 to 3%; 11 studies, 86/2907 events/patients), 4% (3 to 6%; 12 studies, 127/3011 events/patients), and 3% (1 to 5%; 12 studies, 94/3011 events/patients), respectively. • The HRs (95% CI) per 1% increase of MSI for cardiac mortality and congestive heart failure were 0.93 (0.91 to 0.96; 1 study, 14/202 events/patients) and 0.96 (0.93 to 0.99; 1 study, 11/104 events/patients),respectively, but the prognostic value of MSI for myocardial re-infraction has not been measured.

Phenotyping heart failure by cardiac magnetic resonance imaging of cardiac macro- and microscopic structure: state of the art review.

Heart failure demographics have evolved in past decades with the development of improved diagnostics, therapies, and prevention. Cardiac magnetic resonance (CMR) has developed in a similar timeframe to become the gold-standard non-invasive imaging modality for characterizing diseases causing heart failure. CMR techniques to assess cardiac morphology and function have progressed since their first use in the 1980s. Increasingly efficient acquisition protocols generate high spatial and temporal resolution images in less time. This has enabled new methods of characterizing cardiac systolic and diastolic function such as strain analysis, exercise real-time cine imaging and four-dimensional flow. A key strength of CMR is its ability to non-invasively interrogate the myocardial tissue composition. Gadolinium contrast agents revolutionized non-invasive cardiac imaging with the late gadolinium enhancement technique. Further advances enabled quantitative parametric mapping to increase sensitivity at detecting diffuse pathology. Novel methods such as diffusion tensor imaging and artificial intelligence-enhanced image generation are on the horizon. Magnetic resonance spectroscopy (MRS) provides a window into the molecular environment of the myocardium. Phosphorus (31P) spectroscopy can inform the status of cardiac energetics in health and disease. Proton (1H) spectroscopy complements this by measuring creatine and intramyocardial lipids. Hyperpolarized carbon (13C) spectroscopy is a novel method that could further our understanding of dynamic cardiac metabolism. CMR of other organs such as the lungs may add further depth into phenotypes of heart failure. The vast capabilities of CMR should be deployed and interpreted in context of current heart failure challenges.

Abstract 245: Endothelin-1 And Procollagen Type-1 Carboxy-terminal Propeptide Are Associated With Functional Tolerance And Cardiac Structure And Function In Heart Failure With Preserved Ejection Fraction

Introduction: The role of emerging biomarkers such as endothelin-1 (ET-1) and collagen peptides in functional tolerance among patients with heart failure with preserved ejection fraction (HFpEF) is not well understood. Hypothesis: We hypothesize that plasma ET-1 and procollagen type-1 carboxy-terminal propeptide (PICP) are associated with 6-minute walk distance and parameters of cardiac structure and function. Methods: In a cross-sectional cohort study, we evaluated the association of ET-1 and PICP with 6-minute walk distance and parameters of cardiac structure and function on cardiac magnetic resonance (CMR) imaging in patients with HFpEF. In a subset of patients, we used a novel diffusion tensor imaging CMR technique to determine the myocardial fiber orientation in the septum as characterized by the helix angle transmurality (slope of the helix angle versus transmural depth from endocardium to epicardium) (Fig 1C). Results: A total of 36 patients (25 with HFpEF, 11 controls), mean age 70 ± 7.7 yrs, BMI 33 ± 8.5 kg/m 2 , 94% men, 53% had diabetes, and 75% had hypertension. Mean LVEF 58.7 ± 7.7%, RVEF 49.1 ± 10.4%, mean global myocardial mid- LV T1 1285ms, mean LV mass indexed to body surface area 65 ± 12 g/m 2 . Using univariate linear regression, we found that both plasma ET-1 levels and PICP levels were moderately inversely associated with 6-minute walk distance (R 2 -0.56, p&lt;0.001) and (R 2 -0.40, p=0.02) (Fig 1A) respectively, with a non-significant association with age (R 2 = 0.30, p=0.08) and indexed LV mass (R 2 =0.29, p=0.09). ET-1 was moderately associated with septal HAT, a marker of myocardial fiber orientation, (R 2 =0.58, p=0.02), measured in a subset of patients (Fig 1B, C). Conclusions: Plasma ET1 and PICP levels are moderately associated with lower 6-minute walk distance; ET-1 is associated with septal myocardial fiber orientation in this exploratory analysis. Future studies are needed to determine the prognostic value of these biomarkers in patients with HFpEF.

Left Ventricular Adverse Remodeling in Ischemic Heart Disease: Emerging Cardiac Magnetic Resonance Imaging Biomarkers

Post-ischemic left ventricular (LV) remodeling is a biologically complex process involving myocardial structure, LV shape, and function, beginning early after myocardial infarction (MI) and lasting until 1 year. Adverse remodeling is a post-MI maladaptive process that has been associated with long-term poor clinical outcomes. Cardiac Magnetic Resonance (CMR) is the best tool to define adverse remodeling because of its ability to accurately measure LV end-diastolic and end-systolic volumes and their variation over time and to characterize the underlying myocardial changes. Therefore, CMR is the gold standard method to assess in vivo myocardial infarction extension and to detect the presence of microvascular obstruction and intramyocardial hemorrhage, both associated with adverse remodeling. In recent times, new CMR quantitative biomarkers emerged as predictive of post-ischemic adverse remodeling, such as T1 mapping, myocardial strain, and 4D flow. Additionally, CMR T1 mapping imaging may depict infarcted tissue and assess diffuse myocardial fibrosis by using surrogate markers such as extracellular volume fraction, which may predict functional recovery or risk stratification of remodeling. Finally, there is emerging evidence supporting the utility of intracavitary blood flow kinetic energy and hemodynamic features assessed by the 4D flow CMR technique as early predictors of remodeling.

Cardiovascular Magnetic Resonance Parametric Mapping Techniques for the Assessment of Chronic Coronary Syndromes.

The term chronic coronary syndromes encompasses a variety of clinical presentations of coronary artery disease (CAD), ranging from stable angina due to epicardial coronary artery disease to microvascular coronary dysfunction. Cardiac magnetic resonance (CMR) imaging has an established role in the diagnosis, prognostication and treatment planning of patients with CAD. Recent advances in parametric mapping CMR techniques have added value in the assessment of patients with chronic coronary syndromes, even without the need for gadolinium contrast administration. Furthermore, quantitative perfusion CMR techniques have enabled the non-invasive assessment of myocardial blood flow and myocardial perfusion reserve and can reliably identify multivessel coronary artery disease and microvascular dysfunction. This review summarizes the clinical applications and the prognostic value of the novel CMR parametric mapping techniques in the setting of chronic coronary syndromes and discusses their strengths, pitfalls and future directions.

Abstract 12248: Decreased Left Ventricular Hemodynamic Forces As A Novel Biomarker Of Myocardial Dysfunction In Duchenne Muscular Dystrophy

Introduction: Patients with Duchenne muscular dystrophy (DMD) develop progressive cardiomyopathy. Cardiac magnetic resonance (CMR) imaging is used to identify global and regional function, as well as myocardial fibrosis in DMD. Unique left ventricular (LV) biomechanics cannot be assessed through conventional CMR techniques. Thus, we investigated hemodynamic force (HDF) through cine derived wall motion in the LV as a novel biomarker of myocardial dysfunction in DMD patients. Methods: This retrospective study consisted of CMR studies from DMD patients and age-matched controls. Feature-tracking (Qstrain, Medis) was performed on short-axis and long-axis cine imaging to capture LV wall motion. A novel technique based on diffeomorphic mapping was used to calculate three-dimensional LV kinematic models and HDF vectors throughout the cardiac cycle (Figure 1A). The apical-basal, lateral-septal, and anterior-posterior HDF vectors were correlated with global and regional functional parameters. Results: Eleven DMD and 11 controls were enrolled with LV EF 51 ± 6 vs 56 ± 6 (p = 0.09). DMD patients had decreased apical-basal and lateral-septal HDF across multiple points in the cardiac cycle compared to controls (Figure 1B). Six DMD patients with LV EF &lt; 55% were compared to 5 DMD patients with normal EF, demonstrating significant decrease in apical-basal systolic root mean square (RMS) HDF (p = 0.015), lateral-septal systolic RMS HDF (p = 0.009), anterior-posterior diastolic RMS HDF (p = 0.011), and magnitude systolic RMS HDF (p = 0.011) in patients with dysfunction. Absolute magnitude RMS HDF in all axes correlated with LV global longitudinal strain, LV global circumferential strain, and LV EF (r = 0.59 to 0.81, p &lt; 0.05). Conclusions: Cine derived HDF may be a more sensitive measure of LV dysfunction in DMD patients. Apical-basal HDF has potential as a novel biomarker for progression of disease.

Abstract 14447: Multi-Center Evaluation of Stress Myocardial Blood Flow by Cardiac Magnetic Resonance in Known and Suspected Ischemic Heart Disease: Preliminary Findings From the AQUA-MBF Initiative

Introduction: Quantitative myocardial blood flow (MBF) analysis using stress cardiac magnetic resonance (CMR) has been shown to detect obstructive coronary artery disease (CAD) and coronary microvascular dysfunction (CMD) in several mostly small, single-center studies. The AQUA-MBF ( A ssessment of QUA ntitative MBF ) study is a multicenter initiative involving 16 centers. Hypothesis: The goal of this sub-study is to determine if MBF can differentiate CAD, CMD, and normal volunteers in this multicenter setting. Methods: We present data from 53 subjects (15 with CAD, 20 at risk for CMD and 18 controls) who underwent vasodilator stress CMR (Figure) using 1.5T and 3.0T MR scanners (General Electric). At risk for CMD was defined as having diabetes and 2 other risk factors in absence of ≥50% stenosis based on coronary CT. CAD was defined as the presence of stenosis ≥70% based on invasive coronary angiography. Stress perfusion images were acquired using the dual sequence technique. Stress MBF was measured in each of the 16 AHA segments using Fermi deconvolution (Circle Cvi42). In the CAD group, each segment was further classified as having late gadolinium enhancement (LGE), supplied by CAD, or a normal remote territory. The means of the 5 groups were compared using one-way analysis of variance. Results: The segmental stress MBF (ml/g/min) for the 5 groups are shown in figure. Compared to the normal group, segmental stress MBF in 4 disease groups were significantly lower (p&lt;0.001). Segmental MBF in those at risk for CMD was lower than normal segments and greater than CAD segments (p&lt;0.001). LGE and CAD segments had the lowest stress MBF but similar to each other (p=0.9). Conclusions: In this multicenter study, we show that quantification of MBF using the dual sequence stress perfusion CMR technique can differentiate diseased from healthy myocardium and also between obstructive CAD and those at risk for CMD.

Prognostic significance of myocardial salvage assessed by cardiac magnetic resonance in reperfused ST-segment elevation myocardial infarction.

AimsMyocardial salvage index (MSI) is attracting increasing attention for predicting prognosis in acute myocardial infarction (AMI); however, the evaluation of MSI is mainly based on contrast agent-dependent cardiac magnetic resonance (CMR) scanning sequences. This study aims to investigate the prognostic value of MSI in reperfused ST-segment elevation myocardial infarction (STEMI) through the contrast agent-free CMR technique.Methods and resultsNighty-two patients with acute STEMI, who underwent CMR after primary percutaneous coronary intervention (PPCI), were finally enrolled. Patients were subcategorized into two groups according to median MSI. T1 and T2 mapping were conducted for measuring infarct size (IS) and area at risk (AAR). IS was significantly larger in < median MSI group than ≥ median MSI group (P < 0.001). AAR between the two groups showed no obvious differences (P = 0.108). Left ventricular ejection fraction (LVEF) was lower in < median MSI group than ≥ median MSI group (P = 0.014). There was an obvious inverse correlation between MSI and reperfusion time (R = –0.440, P < 0.001) and a strong inverse correlation between MSI and IS (R = –0.716, P = 0.011). As for the relationship LVEF, MSI showed positive but weak correlation (R = 0.2265, P < 0.001). Over a median follow-up period of 263 (227–238) days, prevalence of MACEs was significantly higher in the < median MSI group [HR: 0.15 (0.04–0.62); Log-rank P = 0.008]. The univariate Cox regression analysis revealed that LVEF, IS, and MSI were significant predictors for major adverse cardiovascular events (MACEs) (all P < 0.05). In the stepwise multivariate Cox regression analysis, LVEF and MSI were identified as independent parameters for predicting MACEs (both P < 0.05). In the receiver-operating characteristic analysis, LVEF, IS, and MSI showed prognostic value in predicting MACEs with AUCs of 0.809, 0.779, and 0.896, respectively, all (P < 0.05). A combination of MSI with LVEF showed the strongest prognostic value of MACEs (AUC: 0.901, sensitivity: 77.78%, specificity: 98.80%, P < 0.001). Delong’s test showed that the combination of LVEF with MSI had an incremental value than LVEF itself in predicting MACEs (P = 0.026).ConclusionContrast agent-free CMR technique provides a reliable evaluation of MSI, which contributes to assessing the efficacy of reperfusion therapy and predicting the occurrence of MACEs.

The role of cardiac magnetic resonance imaging in the assessment of heart failure with preserved ejection fraction.

Heart failure (HF) is a major cause of morbidity and mortality worldwide. Current classifications of HF categorize patients with a left ventricular ejection fraction of 50% or greater as HF with preserved ejection fraction or HFpEF. Echocardiography is the first line imaging modality in assessing diastolic function given its practicality, low cost and the utilization of Doppler imaging. However, the last decade has seen cardiac magnetic resonance (CMR) emerge as a valuable test for the sometimes challenging diagnosis of HFpEF. The unique ability of CMR for myocardial tissue characterization coupled with high resolution imaging provides additional information to echocardiography that may help in phenotyping HFpEF and provide prognostication for patients with HF. The precision and accuracy of CMR underlies its use in clinical trials for the assessment of novel and repurposed drugs in HFpEF. Importantly, CMR has powerful diagnostic utility in differentiating acquired and inherited heart muscle diseases presenting as HFpEF such as Fabry disease and amyloidosis with specific treatment options to reverse or halt disease progression. This state of the art review will outline established CMR techniques such as transmitral velocities and strain imaging of the left ventricle and left atrium in assessing diastolic function and their clinical application to HFpEF. Furthermore, it will include a discussion on novel methods and future developments such as stress CMR and MR spectroscopy to assess myocardial energetics, which show promise in unraveling the mechanisms behind HFpEF that may provide targets for much needed therapeutic interventions.

Cardiac Magnetic Resonance Assessment of the Protective Effect of Remote Ischemic Postconditioning on Coronary Microcirculation after Reperfusion Therapy for Acute ST-Segment Elevation Myocardial Infarction.

This study intends to evaluate the characteristics of coronary microcirculatory function in patients with myocardial infarction undergoing reperfusion and its predictive value in assessing cardiac function, myocardial activity, recovery of ventricular wall motion after infarction, and distant myocardial remodeling by cardiac magnetic resonance technique (CMRI). Materials and Methods. The 293 cases of patients with myocardial infarction treated in our hospital from August 2017 to August 2021 were selected as the subjects of this retrospective study, 13 cases were shed due to transfer and moving, and the rest were divided into 140 cases each in the emergency and elective groups according to emergency percutaneous coronary intervention (PCI) and elective PCI. The patients' myocardial infarct volume ventricular volume, microcirculatory obstruction volume ventricular volume, microcirculatory obstruction volume/myocardial infarct volume, and LVEF, combined with BP and troponin T, were analysed by CMR for comparative analysis, hemodynamic, and cardiac function index differences. Results. The hemodynamics (CO, CI, SV, SI, LVSW1, and LCW) measured at different times were significantly different between the two groups; patients in the emergency group had significantly lower EDV and ESV than the elective group at 7-10 d postoperatively; and EDV, ESV, and LVEF improved in both groups after 3 months, while EDV, ESV, and LVEF improved significantly better in the emergency group than in the elective group, and the difference was statistically significant (P < 0.05). The myocardial infarct quality, VSM score, and ventricular wall motion abnormality score were significantly lower in the emergency group than in the elective group from 7 to 10 d after PCI; myocardial infarct quality, VSM score, and ventricular wall motion abnormality score improved in both groups at 3 months after PCI; and the degree of improvement of myocardial infarct quality and VSM score was significantly better in the emergency group than in the elective group (P < 0.05). Conclusion. Acute myocardial infarction patients with significant effect of emergency PCI treatment can be on their postmyocardial infarction left ventricular function, and in the treatment of coronary heart disease, myocardial infarction diagnosis has a certain reference value.

C45 LATE CARDIAC OUTCOMES IN PATIENTS AFTER COVID–19: A CARDIAC MAGNETIC RESONANCE STUDY

BackgroundMyocardial injury can occur in patients with coronavirus disease (COVID)–19. Cardiac magnetic resonance (CMR) provides information on functional and morphological cardiac parameters, as well myocardial tissue characterization. Actually, there are few data on late cardiac outcomes in patients after COVID–19.Aim of the StudyTo assess late functional, morphological and myocardial tissue parameters in patients positive to COVID–19 Methods 55 patients (age 50±16 yrs, Female n = 17) with a prior diagnosis of COVID 19, without a previous history of cardiac disease were enrolled in the study. Of these, 35 were hospitalized. The time interval between COVID–19 diagnosis and CMR was 418±28 days. Cardiac function and myocardial tissue characterization have been evaluated with the current CMR techniques. In particular, the presence of late gadolinium enhancement (LGE), as a sign of myocarditis outcome has been evaluated.ResultsLGE was present in 19 patients (34.5%). In all cases, LGE was localized at the level of lateral wall of left ventricle within the myocardium or at the subepicardial level (non–ischemic pattern). Left and right ventricular (LV, RV) ejection fraction were within normal values (mean±SD 65±5% and 65±7%, respectively), as well as volumes (LV endiastolic and endsystolic volumes 71±15 and 27±8 ml/m2; RV endiastolic and endsystolic volumes 72±15 and 25±9 ml/m2). In one case, LGE was associated to regional wall hypokinesia. Among the hospitalized patients, the following factors were associated to the presence of LGE: prone position during assisted ventilation, duration of hospitalization. LGE was present in 67% of patients put in prone position, against 33% of patients not pronated (p = 0.009 Fisher‘s exact test). Duration of hospitalization was 9±5 and 16±7 respectively in patients without and with LGE (p = 0.007)ConclusionLGE, as an outcome of myocarditis, is present in a significant number of patients with a history of COVID–19, but it is not associated with dilatation or global and regional dysfunction of left ventricle. LGE is mainly present in pts with more severe clinical presentation of COVID–19

Interventional cardiac magnetic resonance imaging: current applications, technology readiness level, and future perspectives.

Background:Cardiac magnetic resonance (CMR) provides excellent temporal and spatial resolution, tissue characterization, and flow measurements. This enables major advantages when guiding cardiac invasive procedures compared with X-ray fluoroscopy or ultrasound guidance. However, clinical implementation is limited due to limited availability of technological advancements in magnetic resonance imaging (MRI) compatible equipment. A systematic review of the available literature on past and present applications of interventional MR and its technology readiness level (TRL) was performed, also suggesting future applications.Methods:A structured literature search was performed using PubMed. Search terms were focused on interventional CMR, cardiac catheterization, and other cardiac invasive procedures. All search results were screened for relevance by language, title, and abstract. TRL was adjusted for use in this article, level 1 being in a hypothetical stage and level 9 being widespread clinical translation. The papers were categorized by the type of procedure and the TRL was estimated.Results:Of 466 papers, 117 papers met the inclusion criteria. TRL was most frequently estimated at level 5 meaning only applicable to in vivo animal studies. Diagnostic right heart catheterization and cavotricuspid isthmus ablation had the highest TRL of 8, meaning proven feasibility and efficacy in a series of humans.Conclusion:This article shows that interventional CMR has a potential widespread application although clinical translation is at a modest level with TRL usually at 5. Future development should be directed toward availability of MR-compatible equipment and further improvement of the CMR techniques. This could lead to increased TRL of interventional CMR providing better treatment.