Recent Advances in Cardiovascular Magnetic Resonance: Techniques and Applications

Advanced statistical inference of myocardial stiffness: A time series Gaussian process approach of emulating cardiac mechanics for real-time clinical decision support

Cardiac mechanics modelling promises to revolutionize personalized health care; however, inferring patient-specific biophysical parameters, which are critical for understanding myocardial functions and performance, poses substantial methodological challenges. Our work is primarily motivated to determine the passive stiffness of the myocardium from the measurement of the left ventricle (LV) volume at various time points, which is crucial for diagnosing cardiac physiological conditions. Although there have been significant advancements in cardiac mechanics modelling, the tasks of inference and uncertainty quantification of myocardial stiffness remain challenging, with high computational costs preventing real-time decision support. We adapt Gaussian processes to construct a statistical surrogate model for emulating LV cavity volume during diastolic filling to overcome this challenge. As the LV volumes, obtained at different time points in diastole, constitute a time series, we apply the Kronecker product trick to decompose the complex covariance matrix of the whole system into two separate covariance matrices, one for time and the other for biophysical parameters. To proceed towards personalized health care, we further integrate patient-specific LV geometries into the Gaussian process emulator using principal component analysis (PCA). Utilizing a deep learning neural network for extracting time-series left ventricle volumes from magnetic resonance images, Bayesian inference is applied to determine the posterior probability distribution of critical cardiac mechanics parameters. Tests on real-patient data illustrate the potential for real-time estimation of myocardial properties for clinical decision-making. These advancements constitute a crucial step towards clinical impact, offering valuable insights into posterior uncertainty quantification for complex cardiac mechanics models.

The Incremental Value of Native T1 Mapping-Derived Radiomics for The Diagnosis of Amyloid Light-Chain Cardiac Amyloidosis

RATIONALE AND OBJECTIVES

This study aimed to assess the incremental diagnostic value of non-contrast T1 mapping-derived radiomics in patients with amyloid light-chain cardiac amyloidosis (AL-CA).

METHODS

We retrospectively collected 86 patients with suspected AL-CA and 28 control patients who underwent cardiac MRI at 3.0 T in our institution, and the MRI data were divided into a training set and a test set. Radiomic features were extracted based on native T1 maps using a freely available software package. We applied LASSO logistic regression method to select radiomic features with high diagnostic value of AL-CA and develop a predictive model. The diagnostic performance of the radiomics model was evaluated using receiver operating characteristic curve analysis and compared to T1 values.

RESULTS

A total of 70 people were diagnosed with AL-CA, and cardiac involvement was observed in 202 myocardial slicers. The accuracy of T1 values for the diagnosis of myocardial involvement was 0.886, with a threshold value of 1375 ms. The radiomics score comprised a total of three features. The radiomics score demonstrated significantly higher sensitivity in detecting myocardial involvement compared to T1 values in both the training set (AUC 0.886 vs. 0.924, P = 0.025) and the test set (0.862 vs 0.915, P = 0.026). The combined model comprising T1 values and a radiomic feature named S(4,-4) Correlat showed higher diagnostic performance in comparison to T1 values alone both in the training and test sets, with AUC values of 0.929 and 0.909, respectively.

CONCLUSION

The radiomic features derived from native T1 mapping demonstrated incremental value for the diagnosis of AL-CA, which may be an alternative to T1-derived ECV to avoid the use of contrast in patients with suspected myocardial involvement in systemic amyloidosis.

Using artificial intelligence and promoter-level transcriptome analysis to identify a biomarker as a possible prognostic predictor of cardiac complications in male patients with Fabry disease

Fabry disease is the most frequently occurring form of lysosomal disease in Japan, and is characterized by a wide variety of conditions. Primarily, the three major types of concerns associated with Fabry disease observed during adulthood that must be prevented are central nervous system, renal, and cardiac complications. Cardiac complications, such as cardiomyopathy, cardiac muscle fibrosis, and severe arrhythmia, are the most common mortality causes in patients with Fabry disease. To predict cardiac complications of Fabry disease, we extracted RNA from the venous blood of patients for cap analysis of gene expression (CAGE), performed likelihood ratio tests for each RNA expression dataset obtained from individuals with and without cardiac complications, and analyzed the correlation between cardiac functional factors observed using magnetic resonance imaging data extracted using artificial intelligence algorithms and RNA expression. Our findings showed that CHN1 expression was significantly higher in male Fabry disease patients with cardiac complications and that it could be associated with many cardiac functional factors. CHN1 encodes a GTPase-activating protein, chimerin 1, which is specific to the GTP-binding protein Rac (involved in oxidative stress generation and the promotion of myocardial fibrosis). Thus, CHN1 is a potential predictive biomarker of cardiac complications in Fabry disease; however, further studies are required to confirm this observation.

Four-Dimensional Flow MRI for Cardiovascular Evaluation (4DCarE): A Prospective Non-Inferiority Study of a Rapid Cardiac MRI Exam: Study Protocol and Pilot Analysis

BACKGROUND

Accurate measurements of flow and ventricular volume and function are critical for clinical decision-making in cardiovascular medicine. Cardiac magnetic resonance (CMR) is the current gold standard for ventricular functional evaluation but is relatively expensive and time-consuming, thus limiting the scale of clinical applications. New volumetric acquisition techniques, such as four-dimensional flow (4D-flow) and three-dimensional volumetric cine (3D-cine) MRI, could potentially reduce acquisition time without loss in accuracy; however, this has not been formally tested on a large scale.

METHODS

4DCarE (4D-flow MRI for cardiovascular evaluation) is a prospective, multi-centre study designed to test the non-inferiority of a compressed 20 min exam based on volumetric CMR compared with a conventional CMR exam (45-60 min). The compressed exam utilises 4D-flow together with a single breath-hold 3D-cine to provide a rapid, accurate quantitative assessment of the whole heart function. Outcome measures are (i) flow and chamber volume measurements and (ii) overall functional evaluation. Secondary analyses will explore clinical applications of 4D-flow-derived parameters, including wall shear stress, flow kinetic energy quantification, and vortex analysis in large-scale cohorts. A target of 1200 participants will enter the study across three sites. The analysis will be performed at a single core laboratory site. Pilot Results: We present a pilot analysis of 196 participants comparing flow measurements obtained by 4D-flow and conventional 2D phase contrast, which demonstrated moderate-good consistency in ascending aorta and main pulmonary artery flow measurements between the two techniques. Four-dimensional flow underestimated the flow compared with 2D-PC, by approximately 3 mL/beat in both vessels.

CONCLUSIONS

We present the study protocol of a prospective non-inferiority study of a rapid cardiac MRI exam compared with conventional CMR. The pilot analysis supports the continuation of the study.

STUDY REGISTRATION

This study is registered with the Australia and New Zealand Clinical Trials Registry (Registry number ACTRN12622000047796, Universal Trial Number: U1111-1270-6509, registered 17 January 2022-Retrospectively registered).

Sex-specific ventricular morphology, function, and tissue characteristics in arterial hypertension: a magnetic resonance study of the Hamburg city health cohort

OBJECTIVE

To determine the influence of arterial hypertension (AHT), sex, and the interaction between both left- and right ventricular (LV, RV) morphology, function, and tissue characteristics.

METHODS

The Hamburg City Health Study (HCHS) is a population-based, prospective, monocentric study. 1972 individuals without a history of cardiac diseases/ interventions underwent 3 T cardiac MR imaging (CMR). Generalized linear models were conducted, including AHT, sex (and the interaction if significant), age, body mass index, place of birth, diabetes mellitus, smoking, hyperlipoproteinemia, atrial fibrillation, and medication.

RESULTS

Of 1972 subjects, 68% suffered from AHT. 42% with AHT and 49% controls were female. Females overall showed a higher ejection fraction (EF) (LV: regression coefficient +2.4% [95% confidence interval: 1.7; 3.1]), lower volumes and LV mass (-19.8% [-21.3; -18.5]), and prolonged native septal T1 (+22.1 ms [18.3; 25.9])/T2 relaxation times (+1.1 ms [0.9; 1.3]) (all p < 0.001) compared to males. Subjects with AHT showed a higher EF (LV: +1.2% [0.3; 2.0], p = 0.009) and LV mass (+6.6% [4.3; 9.0], p < 0.001) than controls. The interaction between sex and AHT influenced mapping. After excluding segments with LGE, males (-0.7 ms [-1.0; -0.3 | ) and females with AHT (-1.1 ms [-1.6; -0.6]) showed shorter T2 relaxation times than the sex-respective controls (p < 0.001), but the effect was stronger in females.

CONCLUSION

In the HCHS, female and male subjects with AHT likewise showed a higher EF and LV mass than controls, independent of sex. However, differences in tissue characteristics between subjects with AHT and controls appeared to be sex-specific.

CLINICAL RELEVANCE STATEMENT

The interaction between sex and cardiac risk factors is an underestimated factor that should be considered when comparing tissue characteristics between hypertensive subjects and controls, and when establishing cut-off values for normal and pathological relaxation times.

KEY POINTS

There are sex-dependent differences in arterial hypertension, but it is unclear if cardiac MR parameters are sex-specific. Differences in cardiac MR parameters between hypertensive subjects and healthy controls appeared to be sex-specific for tissue characteristics. Sex needs to be considered when comparing tissue characteristics in patients with arterial hypertension to healthy controls.

Assessing diastolic function using CMR as an alternative to echocardiography: age- and gender-related normal reference values

BACKGROUND

Impaired diastolic function is associated with a variety of diseases such as myocarditis or dilated cardiomyopathy. Currently, echocardiography is the standard method for assessing diastolic function. Recently, it has been postulated that cardiovascular magnetic resonance (CMR) is an at least equivalent or superior alternative to echocardiography. To assess CMR-based age- and gender-dependent diastolic functional normal reference values, pulmonary venous and transmitral blood-flow parameters were examined in heart-healthy test persons.

METHODS AND RESULTS

Flow-sensitive phase-contrast CMR imaging was performed in the right upper pulmonary vein (RUPV) and at the level of the mitral valve (MV) in 183 healthy subjects (age 10-70 years; 97 women, 86 men). The data was distributed as evenly as possible across all groups. Strong age-dependence was observed for PV S/D; r = 0.718, p < 0.001 (Pearson product-moment correlation) and for transmitral MV E/A; ρ = -0.736, p < 0.001 (Spearman's Rho correlation). Moderate age-dependence was found for PV slope D-wave; r = 0.394, p < 0.001. Except for MV slope E-wave (male -292 cm/s2 interquartile range (IQR) {-338; -243} vs. female -319 ± 82 cm/s2; p = 0.047), no gender-related differences were observed. In a subgroup (N = 100), CMR data were compared with echocardiographic data. Strong correlation was found between CMR and echocardiography for PV S/D; r = 0.545, p < 0.001 and MV E/A; ρ = 0.692, p < 0.001.

CONCLUSION

Diastolic functional parameters change with age, while gender-differences are small. CMR and echocardiography showed similar PV S/D and MV E/A ratios, making CMR a promising alternative for assessing diastolic function.

Emerging opportunities to target inflammation: myocardial infarction and type 2 diabetes

After myocardial infarction (MI), patients with type 2 diabetes have an increased rate of adverse outcomes, compared to patients without. Diabetes confers a 1.5-2-fold increase in early mortality and, importantly, this discrepancy has been consistent over recent decades, despite advances in treatment and overall survival. Certain assumptions have emerged to explain this increased risk, such as differences in infarct size or coronary artery disease severity. Here, we re-evaluate that evidence and show how contemporary analyses using state-of-the-art characterization tools suggest that the received wisdom tells an incomplete story. Simultaneously, epidemiological and mechanistic biological data suggest additional factors relating to processes of diabetes-related inflammation might play a prominent role. Inflammatory processes after MI mediate injury and repair and are thus a potential therapeutic target. Recent studies have shown how diabetes affects immune cell numbers and drives changes in the bone marrow, leading to pro-inflammatory gene expression and functional suppression of healing and repair. Here, we review and re-evaluate the evidence around adverse prognosis in patients with diabetes after MI, with emphasis on how targeting processes of inflammation presents unexplored, yet valuable opportunities to improve cardiovascular outcomes in this vulnerable patient group.

Unraveling the Nexus Between Ambient Air Pollutants and Cardiovascular Morbidity: Mechanistic Insights and Therapeutic Horizons

Air pollution poses a significant threat to cardiovascular health, contributing to the development and progression of various heart diseases. This review delves into the intricate relationship between ambient air pollutants and cardiovascular morbidity, elucidating the underlying mechanisms and exploring potential therapeutic approaches. We discuss the major types of air pollutants, including particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO), and their respective roles in exacerbating cardiovascular conditions. The review highlights the key mechanisms by which air pollutants adversely impact the cardiovascular system, including systemic inflammation, oxidative stress, endothelial dysfunction, autonomic nervous system imbalance, and dysregulation of blood coagulation and thrombosis. Vulnerable populations, including children, the elderly, and those with pre-existing health conditions, are disproportionately affected. Air quality regulations aim to mitigate these effects by reducing pollutant levels, with the overall goal of lowering cardiovascular morbidity and improving public health outcomes. Specifically, stringent regulations focus on curbing vehicular emissions and industrial pollutants and promoting cleaner energy sources. Recent data underscore the importance of addressing environmental and behavioral risk factors to prevent the growing global burden of cardiovascular disease. This review synthesizes the mechanistic pathways through which pollutants contribute to cardiovascular damage and highlights the urgent need for early detection strategies and targeted therapies. Improving public health through stricter air quality control measures and raising awareness of the health risks associated with pollution is crucial for mitigating the long-term cardiovascular impacts of air pollution.

Cardiac Sarcoidosis: Utilizing Cardiac MRI and PET-CT

PURPOSEOF REVIEW

Cardiac sarcoidosis is an inflammatory condition that has been associated with deleterious cardiac manifestations. The diagnosis of cardiac sarcoidosis is challenging and can be guided by advanced cardiac imaging.

RECENT FINDINGS

Endomyocardial biopsy lacks sensitivity in confirming a diagnosis of cardiac sarcoidosis. Studies have shown that the use of cardiac magnetic resonance imaging (MRI) and cardiac Positron Emission Testing (PET) are associated with increased sensitivity and specificity in the diagnosis of cardiac sarcoidosis. Cardiac MRI and cardiac PET CT, although distinct entities, are complimentary in the diagnosis, prognostication of major cardiac events, and aid in the treatment algorithm in patients with cardiac sarcoidosis.

The Role of Artificial Intelligence and Machine Learning in Cardiovascular Imaging and Diagnosis

Cardiovascular diseases remain the leading cause of global mortality, underscoring the critical need for accurate and timely diagnosis. This narrative review examines the current applications and future potential of artificial intelligence (AI) and machine learning (ML) in cardiovascular imaging. We discuss the integration of these technologies across various imaging modalities, including echocardiography, computed tomography, magnetic resonance imaging, and nuclear imaging techniques. The review explores AI-assisted diagnosis in key areas such as coronary artery disease detection, valve disorders assessment, cardiomyopathy classification, arrhythmia detection, and prediction of cardiovascular events. AI demonstrates promise in improving diagnostic accuracy, efficiency, and personalized care. However, significant challenges persist, including data quality standardization, model interpretability, regulatory considerations, and clinical workflow integration. We also address the limitations of current AI applications and the ethical implications of their implementation in clinical practice. Future directions point towards advanced AI architectures, multimodal imaging integration, and applications in precision medicine and population health management. The review emphasizes the need for ongoing collaboration between clinicians, data scientists, and policymakers to realize the full potential of AI in cardiovascular imaging while ensuring ethical and equitable implementation. As the field continues to evolve, addressing these challenges will be crucial for the successful integration of AI technologies into cardiovascular care, potentially revolutionizing diagnostic capabilities and improving patient outcomes.

Cardiac magnetic resonance reveals biventricular impairment in Cushing's syndrome: a multicentre case-control study

PURPOSE

Cushing's syndrome (CS) is associated with severe cardiovascular (CV) morbidity and mortality. Cardiac magnetic resonance (CMR) is the non-invasive gold standard for assessing cardiac structure and function; however, few CMR studies explore cardiac remodeling in patients exposed to chronic glucocorticoid (GC) excess. We aimed to describe the CMR features directly attributable to previous GC exposure in patients with cured or treated endogenous CS.

METHODS

This was a prospective, multicentre, case-control study enrolling consecutive patients with cured or treated CS and patients harboring non-functioning adrenal incidentalomas (NFAI), comparable in terms of sex, age, CV risk factors, and BMI. All patients were in stable condition and had a minimum 24-month follow-up.

RESULTS

Sixteen patients with CS and 15 NFAI were enrolled. Indexed left ventricle (LV) end-systolic volume and LV mass were higher in patients with CS (p = 0.027; p = 0.013); similarly, indexed right ventricle (RV) end-diastolic and end-systolic volumes were higher in patients with CS compared to NFAI (p = 0.035; p = 0.006). Morphological alterations also affected cardiac function, as LV and RV ejection fractions decreased in patients with CS (p = 0.056; p = 0.044). CMR features were independent of metabolic status or other CV risk factors, with fasting glucose significantly lower in CS remission than NFAI (p < 0.001) and no differences in lipid levels or blood pressure.

CONCLUSION

CS is associated with biventricular cardiac structural and functional impairment at CMR, likely attributable to chronic exposure to cortisol excess independently of known traditional risk factors.

Cardiac Cine MRI Using a Commercially Available 0.55-T Scanner

Purpose To compare parameters of left ventricular (LV) and right ventricular (RV) volume and function between a commercially available 0.55-T low-field-strength cardiac cine MRI scanner and a 1.5-T scanner. Materials and Methods In this prospective study, healthy volunteers (May 2022 to July 2022) underwent same-day cine imaging using both scanners (0.55 T, 1.5 T). Volumetric and functional parameters were assessed by two experts. After analyzing the results of a blinded crossover reader study of the healthy volunteers, 20 participants with clinically indicated cardiac MRI were prospectively included (November 2022 to February 2023). In a second blinded expert reading, parameters from clinical 1.5-T scans in these participants were compared with those same-day 0.55-T scans. Results are displayed as Bland-Altman plots. Results Eleven healthy volunteers (mean age: 33 years [95% CI: 27, 40]; four of 11 [36%] female, seven of 11 [64%] male) were included. Very strong mean correlation was observed (r = 0.98 [95% CI: 0.97, 0.98]). Average deviation between MRI systems was 1.6% (95% CI: 0.3, 2.9) for both readers. Twenty participants with clinically indicated cardiac MRI were included (mean age: 55 years [95% CI: 48, 62], six of 20 [30%] female, 14 of 20 [70%] male). Mean correlation was very strong (r = 0.98 [95% CI: 0.97, 0.98]). LV and RV parameters demonstrated an average deviation of 1.1% (95% CI: 0.1, 2.1) between MRI systems. Conclusion Cardiac cine MRI at 0.55 T yielded comparable results for quantitative biventricular volumetric and functional parameters compared with routine imaging at 1.5 T, if acquisition time is doubled. Keywords: Cardiac, Comparative Studies, Heart, Cardiovascular MRI, Cine, Myocardium Supplemental material is available for this article. ©RSNA, 2024.

Recommendations for cardiovascular magnetic resonance and computed tomography in congenital heart disease: a consensus paper from the CMR/CCT Working Group of the Italian Society of Pediatric Cardiology and the Italian College of Cardiac Radiology endorsed by the Italian Society of Medical and Interventional Radiology (Part II)

Cardiovascular magnetic resonance (CMR) and computed tomography (CCT) are advanced imaging modalities that recently revolutionized the conventional diagnostic approach to congenital heart diseases (CHD), supporting echocardiography and often replacing cardiac catheterization. This is the second of two complementary documents, endorsed by experts from the Working Group of the Italian Society of Pediatric Cardiology and the Italian College of Cardiac Radiology of the Italian Society of Medical and Interventional Radiology, aimed at giving updated indications on the appropriate use of CMR and CCT in different clinical CHD settings, in both pediatrics and adults. In this article, support is also given to radiologists, pediatricians, cardiologists, and cardiac surgeons for indications and appropriateness criteria for CMR and CCT in the most referred CHD, following the proposed new criteria presented and discussed in the first document. This second document also examines the impact of devices and prostheses for CMR and CCT in CHD and additionally presents some indications for CMR and CCT exams when sedation or narcosis is needed.

Characterization of bone marrow lesions in axial spondyloarthritis using quantitative T1 mapping MRI

OBJECTIVE

Conventional magnetic resonance imaging (MRI) uses T1-weighted and short-tau inversion recovery (STIR) sequences to characterize bone marrow in axial spondyloarthritis. However, quantification is restricted to estimating the extent of lesions because signal intensities are highly variable both within individuals and across patients and MRI scanners. This study evaluates the performance of quantitative T1 mapping for distinguishing different types of bone marrow lesions of the sacroiliac joints.

MATERIALS AND METHODS

In this prospective study, 62 patients underwent computed tomography (CT) and MRI of the sacroiliac joints including T1, STIR, and T1 mapping. Bone marrow lesions were characterized by three readers and assigned to one of four groups: sclerosis, osteitis, fat lesions, and mixed marrow lesions. Relaxation times on T1 maps were compared using generalized estimating equations and receiver operating characteristics (ROC) analysis.

RESULTS

A total of 119 lesions were selected (sclerosis: 38, osteitis: 27, fat lesions: 40; mixed lesions: 14). T1 maps showed highly significant differences between the lesions with the lowest values for sclerosis (1516±220 ms), followed by osteitis (1909±75 ms), and fat lesions (2391±200 ms); p<0.001. T1 mapping differentiated lesions with areas under the ROC curve of 99% (sclerosis vs. osteitis) and 100% (other comparisons).

CONCLUSION

T1 mapping allows accurate characterization of sclerosis, osteitis, and fat lesions at the sacroiliac joint but only for homogeneous, non-mixed lesions. Thus, further sequence development is needed before implementation in clinical routine.

Correlation of Noninvasive Cardiac MRI Measures of Left Ventricular Myocardial Function and Invasive Pressure-Volume Parameters in a Porcine Ischemia-Reperfusion Model

Purpose To assess the correlation between noninvasive cardiac MRI-derived parameters with pressure-volume (PV) loop data and evaluate changes in left ventricular function after myocardial infarction (MI). Materials and Methods Sixteen adult female swine were induced with MI, with six swine used as controls and 10 receiving platelet-derived growth factor-AB (PDGF-AB). Load-independent measures of cardiac function, including slopes of end-systolic pressure-volume relationship (ESPVR) and preload recruitable stroke work (PRSW), were obtained on day 28 after MI. Cardiac MRI was performed on day 2 and day 28 after infarct. Global longitudinal strain (GLS) and global circumferential strain (GCS) were measured. Ventriculo-arterial coupling (VAC) was derived from PV loop and cardiac MRI data. Pearson correlation analysis was performed. Results GCS (r = 0.60, P = .01), left ventricular ejection fraction (LVEF) (r = 0.60, P = .01), and cardiac MRI-derived VAC (r = 0.61, P = .01) had a significant linear relationship with ESPVR. GCS (r = 0.75, P < .001) had the strongest significant linear relationship with PRSW, followed by LVEF (r = 0.67, P = .005) and cardiac MRI-derived VAC (r = 0.60, P = .01). GLS was not significantly correlated with ESPVR or PRSW. There was a linear correlation (r = 0.82, P < .001) between VAC derived from cardiac MRI and from PV loop data. GCS (-3.5% ± 2.3 vs 0.5% ± 1.4, P = .007) and cardiac MRI-derived VAC (-0.6 ± 0.6 vs 0.3 ± 0.3, P = .001) significantly improved in the animals treated with PDGF-AB 28 days after MI compared with controls. Conclusion Cardiac MRI-derived parameters of MI correlated with invasive PV measures, with GCS showing the strongest correlation. Cardiac MRI-derived measures also demonstrated utility in assessing therapeutic benefit using PDGF-AB. Keywords: Cardiac MRI, Myocardial Infarction, Pressure Volume Loop, Strain Imaging, Ventriculo-arterial Coupling Supplemental material is available for this article. © RSNA, 2024.

Screening and diagnosis of cardiovascular disease using artificial intelligence-enabled cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) is the gold standard for cardiac function assessment and plays a crucial role in diagnosing cardiovascular disease (CVD). However, its widespread application has been limited by the heavy resource burden of CMR interpretation. Here, to address this challenge, we developed and validated computerized CMR interpretation for screening and diagnosis of 11 types of CVD in 9,719 patients. We propose a two-stage paradigm consisting of noninvasive cine-based CVD screening followed by cine and late gadolinium enhancement-based diagnosis. The screening and diagnostic models achieved high performance (area under the curve of 0.988 ± 0.3% and 0.991 ± 0.0%, respectively) in both internal and external datasets. Furthermore, the diagnostic model outperformed cardiologists in diagnosing pulmonary arterial hypertension, demonstrating the ability of artificial intelligence-enabled CMR to detect previously unidentified CMR features. This proof-of-concept study holds the potential to substantially advance the efficiency and scalability of CMR interpretation, thereby improving CVD screening and diagnosis.

Underlying mechanisms and cardioprotective effects of SGLT2i and GLP-1Ra: insights from cardiovascular magnetic resonance

Originally designed as anti-hyperglycemic drugs, Glucagon-Like Peptide-1 receptor agonists (GLP-1Ra) and Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have demonstrated protective cardiovascular effects, with significant impact on cardiovascular morbidity and mortality. Despite several mechanisms have been proposed, the exact pathophysiology behind these effects is not yet fully understood. Cardiovascular imaging is key for the evaluation of diabetic patients, with an established role from the identification of early subclinical changes to long-term follow up and prognostic assessment. Among the different imaging modalities, CMR may have a key-role being the gold standard for volumes and function assessment and having the unique ability to provide tissue characterization. Novel techniques are also implementing the possibility to evaluate cardiac metabolism through CMR and thereby further increasing the potential role of the modality in this context. Aim of this paper is to provide a comprehensive review of changes in CMR parameters and novel CMR techniques applied in both pre-clinical and clinical studies evaluating the effects of SGLT2i and GLP-1Ra, and their potential role in better understanding the underlying CV mechanisms of these drugs.

Role of epicardial adipose tissue in diabetic cardiomyopathy through the lens of cardiovascular magnetic resonance imaging - a narrative review

Accumulating evidence suggests that ectopic/visceral adiposity may play a key role in the pathogenesis of nonischaemic cardiovascular diseases associated with type 2 diabetes. Epicardial adipose tissue (EAT) is a complex visceral fat depot, covering 80% of the cardiac surface with anatomical and functional contiguity to the myocardium and coronary arteries. EAT interacts with the biology of the underlying myocardium by secreting a wide range of adipokines. Magnetic resonance imaging (MRI) is the reference modality for structural and functional imaging of the heart. The technique is now also emerging as the reference imaging modality for EAT quantification. With this narrative review, we (a) surveyed contemporary clinical studies that utilized cardiovascular MRI to characterize EAT (studies published 2010-2023); (b) listed the clinical trials monitoring the response to treatment in EAT size as well as myocardial functional and structural parameters and (c) discussed the potential pathophysiological role of EAT in the development of diabetic cardiomyopathy. We concluded that increased EAT quantity and its inflammatory phenotype correlate with early signs of left ventricle dysfunction and may have a role in the pathogenesis of cardiac disease in diabetes with and without coronary artery disease.

Cardiometabolic biomarker patterns associated with cardiac MRI defined fibrosis and microvascular dysfunction in patients with heart failure with preserved ejection fraction

Introduction

Heart failure with preserved ejection fraction (HFpEF) is a complex disease process influenced by metabolic disorders, systemic inflammation, myocardial fibrosis, and microvascular dysfunction. The goal of our study is to identify potential relationships between plasma biomarkers and cardiac magnetic resonance (CMR) imaging markers in patients with HFpEF.

Methods

Nineteen subjects with HFpEF and 15 age-matched healthy controls were enrolled and underwent multiparametric CMR and plasma biomarker analysis using the Olink® Cardiometabolic Panel (Olink Proteomics, Uppsala, Sweden). Partial least squares discriminant analysis (PLS-DA) was used to characterize CMR and biomarker variables that differentiate the subject groups into two principal components. Orthogonal projection to latent structures by partial least squares (OPLS) analysis was used to identify biomarker patterns that correlate with myocardial perfusion reserve (MPR) and extracellular volume (ECV) mapping.

Results

A PLS-DA could differentiate between HFpEF and normal controls with two significant components explaining 79% (Q2 = 0.47) of the differences. For OPLS, there were 7 biomarkers that significantly correlated with ECV (R2 = 0.85, Q = 0.53) and 6 biomarkers that significantly correlated with MPR (R2 = 0.92, Q2 = 0.32). Only 1 biomarker significantly correlated with both ECV and MPR.

Discussion

Patients with HFpEF have unique imaging and biomarker patterns that suggest mechanisms associated with metabolic disease, inflammation, fibrosis and microvascular dysfunction.

Recent Advances in Cardiac Magnetic Resonance for Imaging of Acute Myocardial Infarction

Acute myocardial infarction (AMI) is one of the primary causes of death worldwide, with a high incidence and mortality rate. Assessment of the infarcted and surviving myocardium, along with microvascular obstruction, is crucial for risk stratification, treatment, and prognosis in patients with AMI. Nonionizing radiation, excellent soft tissue contrast resolution, a large field of view, and multiplane imaging make cardiac magnetic resonance (CMR) a "one-stop" method for assessing cardiac structure, function, perfusion, and metabolism. Hence, this imaging technology is considered the "gold standard" for evaluating myocardial function and viability in AMI. This review critically compares the advantages and disadvantages of CMR with other cardiac imaging technologies, and relates the imaging findings to the underlying pathophysiological processes in AMI. A more thorough understanding of CMR technology will clarify their advanced clinical diagnosis and prognostic assessment applications, and assess the future approaches and challenges of CMR in the setting of AMI.

Cardiac MRI at Low Field Strengths

Cardiac MR imaging is well established for assessment of cardiovascular structure and function, myocardial scar, quantitative flow, parametric mapping, and myocardial perfusion. Despite the clear evidence supporting the use of cardiac MRI for a wide range of indications, it is underutilized clinically. Recent developments in low-field MRI technology, including modern data acquisition and image reconstruction methods, are enabling high-quality low-field imaging that may improve the cost-benefit ratio for cardiac MRI. Studies to-date confirm that low-field MRI offers high measurement concordance and consistent interpretation with clinical imaging for several routine sequences. Moreover, low-field MRI may enable specific new clinical opportunities for cardiac imaging such as imaging near metal implants, MRI-guided interventions, combined cardiopulmonary assessment, and imaging of patients with severe obesity. In this review, we discuss the recent progress in low-field cardiac MRI with a focus on technical developments and early clinical validation studies. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 1.

Computing thickness of irregularly-shaped thin walls using a locally semi-implicit scheme with extrapolation to solve the Laplace equation: Application to the right ventricle

Cardiac Magnetic Resonance (CMR) Imaging is currently considered the gold standard imaging modality in cardiology. However, it is accompanied by a tradeoff between spatial resolution and acquisition time. Providing accurate measures of thin walls relative to the image resolution may prove challenging. One such anatomical structure is the cardiac right ventricle. Methods for measuring thickness of wall-like anatomical structures often rely on the Laplace equation to provide point-to-point correspondences between both boundaries. This work presents limex, a novel method to solve the Laplace equation using ghost nodes and providing extrapolated values, which is tested on three different datasets: a mathematical phantom, a set of biventricular segmentations from CMR images of ten pigs and the database used at the RV Segmentation Challenge held at MICCAI'12. Thickness measurements using the proposed methodology are more accurate than state-of-the-art methods, especially with the coarsest image resolutions, yielding mean L1 norms of the error between 43.28% and 86.52% lower than the second-best methods on the different test datasets. It is also computationally affordable. Limex has outperformed other state-of-the-art methods in classifying RV myocardial segments by their thickness.

Optimizing Clinical Cardiac MRI Workflow through Single Breath-Hold Compressed Sensing Cine: An Evaluation of Feasibility and Efficiency

BACKGROUND

Although compressed sensing (CS) accelerated cine holds immense potential to replace conventional cardiovascular magnetic resonance (CMR) cine, how to use CS-based cine appropriately during clinical CMR examinations still needs exploring.

METHODS

A total of 104 patients (46.5 ± 17.1 years) participated in this prospective study. For each participant, a balanced steady state free precession (bSSFP) cine was acquired as a reference, followed by two CS accelerated cine sequences with identical parameters before and after contrast injection. Lastly, a CS accelerated cine sequence with an increased flip angle was obtained. We subsequently compared scanning time, image quality, and biventricular function parameters between these sequences.

RESULTS

All CS cine sequences demonstrated significantly shorter acquisition times compared to bSSFPref cine (p < 0.001). The bSSFPref cine showed higher left ventricular ejection fraction (LVEF) than all CS cine sequences (all p < 0.001), but no significant differences in LVEF were observed among the three CS cine sequences. Additionally, CS cine sequences displayed superior global image quality (p < 0.05) and fewer artifacts than bSSFPref cine (p < 0.005). Unenhanced CS cine and enhanced CS cine with increased flip angle showed higher global image quality than other cine sequences (p < 0.005).

CONCLUSION

Single breath-hold CS cine delivers precise biventricular function parameters and offers a range of benefits including shorter scan time, better global image quality, and diminished motion artifacts. This innovative approach holds great promise in replacing conventional bSSFP cine and optimizing the CMR examination workflow.

Non-invasive pressure-volume loops using the elastance model and CMR: a porcine validation at transient pre-loads

Aims

Pressure-volume (PV) loops have utility in the evaluation of cardiac pathophysiology but require invasive measurements. Recently, a time-varying elastance model to derive PV loops non-invasively was proposed, using left ventricular (LV) volume by cardiovascular magnetic resonance (CMR) and brachial cuff pressure as inputs. Validation was performed using CMR and pressure measurements acquired on the same day, but not simultaneously, and without varying pre-loads. This study validates the non-invasive elastance model used to estimate PV loops at varying pre-loads, compared with simultaneous measurements of invasive pressure and volume from real-time CMR, acquired concurrent to an inferior vena cava (IVC) occlusion.

Methods and results

We performed dynamic PV loop experiments under CMR guidance in 15 pigs (n = 7 naïve, n = 8 with ischaemic cardiomyopathy). Pre-load was altered by IVC occlusion, while simultaneously acquiring invasive LV pressures and volumes from real-time CMR. Pairing pressure and volume signals yielded invasive PV loops, and model-based PV loops were derived using real-time LV volumes. Haemodynamic parameters derived from invasive and model-based PV loops were compared. Across 15 pigs, 297 PV loops were recorded. Intra-class correlation coefficient (ICC) agreement was excellent between model-based and invasive parameters: stroke work (bias = 0.007 ± 0.03 J, ICC = 0.98), potential energy (bias = 0.02 ± 0.03 J, ICC = 0.99), ventricular energy efficiency (bias = -0.7 ± 2.7%, ICC = 0.98), contractility (bias = 0.04 ± 0.1 mmHg/mL, ICC = 0.97), and ventriculoarterial coupling (bias = 0.07 ± 0.15, ICC = 0.99). All haemodynamic parameters differed between naïve and cardiomyopathy animals (P < 0.05). The invasive vs. model-based PV loop dice similarity coefficient was 0.88 ± 0.04.

Conclusion

An elastance model-based estimation of PV loops and associated haemodynamic parameters provided accurate measurements at transient loading conditions compared with invasive PV loops.

A generalised deep meta-learning model for automated quality control of cardiovascular magnetic resonance images

BACKGROUND AND OBJECTIVES

Cardiovascular magnetic resonance (CMR) imaging is a powerful modality in functional and anatomical assessment for various cardiovascular diseases. Sufficient image quality is essential to achieve proper diagnosis and treatment. A large number of medical images, the variety of imaging artefacts, and the workload of imaging centres are amongst the factors that reveal the necessity of automatic image quality assessment (IQA). However, automated IQA requires access to bulk annotated datasets for training deep learning (DL) models. Labelling medical images is a tedious, costly and time-consuming process, which creates a fundamental challenge in proposing DL-based methods for medical applications. This study aims to present a new method for CMR IQA when there is limited access to annotated datasets.

METHODS

The proposed generalised deep meta-learning model can evaluate the quality by learning tasks in the prior stage and then fine-tuning the resulting model on a small labelled dataset of the desired tasks. This model was evaluated on the data of over 6,000 subjects from the UK Biobank for five defined tasks, including detecting respiratory motion, cardiac motion, Aliasing and Gibbs ringing artefacts and images without artefacts.

RESULTS

The results of extensive experiments show the superiority of the proposed model. Besides, comparing the model's accuracy with the domain adaptation model indicates a significant difference by using only 64 annotated images related to the desired tasks.

CONCLUSION

The proposed model can identify unknown artefacts in images with acceptable accuracy, which makes it suitable for medical applications and quality assessment of large cohorts. CODE AVAILABILITY: https://github.com/HosseinSimchi/META-IQA-CMRImages.

CMR is vital in the management of cardiology inpatients: a tertiary centre experience

To review the utility of cardiovascular magnetic resonance (CMR) in the management of hospital inpatients, we performed a retrospective review of all inpatient CMR scans performed over a six-month period at a tertiary referral cardiology centre. Patient demographics, indication for CMR imaging, results of the CMR scans and whether the results changed patient management were recorded. Change in management included medication changes, subsequent invasive procedures, or avoidance of such, and hospital discharge. Overall, 169 patients were included in the study cohort, 66% were male, mean age was 57.1 years. The most common indication for inpatient CMR was to investigate for cardiomyopathy (53% of patients). The most prevalent diagnosis post- CMR in our cohort was ischaemic heart disease, including ischaemic cardiomyopathy and coronary artery disease. There was a complete change in diagnosis or additional diagnosis found in 29% of patients following CMR. Overall, inpatient CMR led to a change in management in 77% of patients; the most common being changes to medication regimen. CMR was well tolerated in 99% of patients and image quality was diagnostic in 93% of cine scans performed. In conclusion, CMR is vital for the management of cardiology inpatients, having an impact that is at least as significant as in the management of outpatients.

Data-efficient Bayesian learning for radial dynamic MR reconstruction

BACKGROUND

Cardiac MRI has become the gold-standard imaging technique for assessing cardiovascular morphology and function. In spite of this, its slow data acquisition process presents imaging challenges due to the motion from heartbeats, respiration, and blood flow. In recent studies, deep learning (DL) algorithms have shown promising results for the task of image reconstruction. However, there have been instances where they have introduced artifacts that may be misinterpreted as pathologies or may obscure the detection of pathologies. Therefore, it is important to obtain a metric, such as the uncertainty of the network output, that identifies such artifacts. However, this can be quite challenging for large-scale image reconstruction problems such as dynamic multi-coil non-Cartesian MRI.

PURPOSE

To efficiently quantify uncertainties of a physics-informed DL-based image reconstruction method for a large-scale accelerated 2D multi-coil dynamic radial MRI reconstruction problem, and demonstrate the benefits of physics-informed DL over model-agnostic DL in reducing uncertainties while at the same time improving image quality.

METHODS

We extended a recently proposed physics-informed 2D U-Net that learns spatio-temporal slices (named XT-YT U-Net), and employed it for the task of uncertainty quantification (UQ) by using Monte Carlo dropout and a Gaussian negative log-likelihood loss function. Our data comprised 2D dynamic MR images acquired with a radial balanced steady-state free precession sequence. The XT-YT U-Net, which allows for training with a limited amount of data, was trained and validated on a dataset of 15 healthy volunteers, and further tested on data from four patients. An extensive comparison between physics-informed and model-agnostic neural networks (NNs) concerning the obtained image quality and uncertainty estimates was performed. Further, we employed calibration plots to assess the quality of the UQ.

RESULTS

The inclusion of the MR-physics model of data acquisition as a building block in the NN architecture led to higher image quality (NRMSE:- 33 ± 8.2 % $-33 \pm 8.2 \%$ , PSNR:6.3 ± 1.3 % $6.3 \pm 1.3 \%$ , and SSIM:1.9 ± 0.96 % $1.9 \pm 0.96 \%$ ), lower uncertainties (- 46 ± 8.7 % $-46 \pm 8.7 \%$ ), and, based on the calibration plots, an improved UQ compared to its model-agnostic counterpart. Furthermore, the UQ information can be used to differentiate between anatomical structures (e.g., coronary arteries, ventricle boundaries) and artifacts.

CONCLUSIONS

Using an XT-YT U-Net, we were able to quantify uncertainties of a physics-informed NN for a high-dimensional and computationally demanding 2D multi-coil dynamic MR imaging problem. In addition to improving the image quality, embedding the acquisition model in the network architecture decreased the reconstruction uncertainties as well as quantitatively improved the UQ. The UQ provides additional information to assess the performance of different network approaches.

Isolated myocardial edema in cardiac magnetic resonance - in search of a management strategy

Isolated myocardial edema not accompanied by late gadolinium enhancement (LGE) may be occasionally found on cardiac magnetic resonance (CMR). This type of picture may be encountered in patients with suspected myocarditis, post some acute cardiac events, with cardiac allograft rejection or even in athletes after an extreme exercise. Currently, there is no clear management strategy for this type of incidental finding. In this narrative review we discuss the methods and pitfalls of edema detection with means of CMR, review published data on isolated myocardial edema for each of the most probable clinical scenarios and propose a structured clinical decision-making algorithm to help clinicians navigate through this type of CMR result. Finally, we highlight the most important gaps in evidence related to isolated myocardial edema without fibrosis, where further research is particularly needed.

MR imaging of primary benign cardiac tumors in the pediatric population

Primary cardiac tumors are rare in all ages, especially in children, with a reported prevalence range of 0.0017-0.28% in autopsy series. Due to their rarity, the diagnostic and therapeutic pathways reserved to them are usually described by single case reports, leading to the point where a common diagnostic protocol is imperative to obtain a differential diagnosis. The first diagnostic approach is done with transthoracic echocardiogram (TTE), due to its wide availability, low cost, absence of ionizing radiations and non-invasiveness. Several tumors are discovered incidentally and, in many cases, TTE is helpful to determine location, size and anatomical features, playing a key role in the differential diagnosis. In the last few years, cardiac magnetic resonance imaging (CMR) has had an increased role in the diagnostic pathway of pediatric cardiac masses, due to its high accuracy in characterizing mass tissue properties (especially for soft tissue), and in detecting tumor size, extent, pericardial/pleural effusion, leading to the correct diagnosis, treatment and follow-up. Therefore, nowadays, several consensus statements consider CMR as a leading imaging technique, thanks to its non-invasive tissue characterization, without the use of ionizing radiation, in an unrestricted field of view. As suggested by the most recent literature, the pediatric protocol is not so different from the adult one, adapted to the size and cardiac frequency of the patient, sometimes requiring special conditions such as free-breathing sequences and/or sedation or general anesthesia in non-cooperating patients.

Transcatheter Tricuspid Valve Replacement: Case Selection, Technical Considerations, and Procedural Planning

Tricuspid regurgitation (TR) is a highly prevalent valve disorder in the US, with prevalence increasing with age. Without treatment, severe TR carries a poor prognosis. Tricuspid valve (TV) surgery is recommended for patients with severe TR undergoing left-sided valve surgery. Transcatheter TV repair or transcatheter TV replacement are potential options for patients who are not surgical candidates. A few small studies have demonstrated the feasibility and efficacy of transcatheter TV repair in patients with severe symptomatic TR. Careful patient selection by assessing tricuspid valve anatomy, right ventricular and pulmonary hemodynamics, candidacy for anticoagulation, comorbid conditions, and frailty is key to procedural success. Transcatheter TV repair can be performed via the transjugular or transfemoral access, and requires a large-caliber sheath (up to 45 Fr) and delivery system, particularly with dilated tricuspid annulus due to right ventricular enlargement. Multimodality imaging is essential for diagnosing TR severity, defining valve anatomy, and comprehensive functional assessment of the tricuspid valve, right atrium, and right ventricle. Several prosthetic valves, including the EVOQUE system, NaviGate system, Intrepid valve, and Cardiovalve, are currently being investigated in clinical trials.

Multimodality imaging assessment of primary pericardial rhabdomyosarcoma: a case report

Primary pericardial sarcomas are rare and lethal diseases. To date, only a few cases of primary pericardial sarcomas, such as rhabdomyosarcoma (RMS), have been reported. Since the unusual location of RMS in the pericardium makes it challenging to diagnose, precise diagnostic procedures are required. In this study, we present the case of a 23-year-old man who experienced postprandial obstruction and atypical precordial pain that lasted for a week. Echocardiography revealed a heterogeneous isoechoic pericardial mass with a significant pericardial effusion. Contrast-enhanced CT revealed a massive pericardial effusion along with an irregular, defined, heterogeneously enhancing mass that was located between the pericardium and diaphragm. PET-CT imaging showed an intense FDG uptake in the pericardial mass. Furthermore, cardiac MRI demonstrated malignant characteristics of the pericardial mass and provided a detailed visualization of its exact anatomical connection with both cardiac and extracardiac structures. Finally, a pathologic examination of a puncture biopsy specimen confirmed the diagnosis of primary pericardial RMS. Our case emphasizes the importance of multimodal imaging for the differential diagnosis and evaluation of cardiac involvement, while providing clinicians with crucial information for clinical treatment and decision-making.

Case report: Aborted sudden cardiac death as a first presentation of severe mitral annulus disjunction-a case series and review of the literature

Mitral annulus disjunction (MAD) is defined as a systolic displacement between the ventricular myocardium and the posterior mitral annulus supporting the posterior mitral leaflet. This structural abnormality is associated with the loss of mechanical annular function manifested as an abnormal systolic excursion of the leaflet hinge point into the left atrium but with maintained electrical function, separating the left atrium and ventricle electrophysiologically. The mitro-aortic fibrous continuity limits MAD anteriorly, between the aortic cusps and the anterior leaflet of the mitral valve. Consequently, MAD has been observed only at the insertion of the posterior leaflet. It can extend preferentially at the central posterior scallop. The first diagnostic modality aiding the diagnosis is transthoracic echocardiography (TTE), although in some cases adjunctive cardiac imaging modality might be suggested. MAD carries a strong association with malignant ventricular arrhythmogenesis and a profound predisposition for sudden cardiac death (SCD). In this context, a thorough investigation of this morphological and functional abnormality is vital in estimating the risk assessment and stratification for optimal management and elimination of the risk of the patient for SCD. Based on the current scientific data and literature, we will discuss the diagnosis, clinical implications, risk stratification, and therapeutic management of MAD.

Aortic Valvular Stenosis and Heart Failure: Advances in Diagnostic, Management, and Intervention

Up to 30% of patients with aortic stenosis (AS) present with heart failure (HF) symptoms with either reduced or preserved left ventricular ejection fraction. Many of these patients present with a low-flow state, reduced aortic-valve-area (≤1.0 cm²) with low aortic-mean-gradient and aortic-peak-velocity (<40 mm Hg and <4.0 m/s). Thus, determination of true severity is essential for correct management, and multi-imaging evaluation must be performed. Medical treatment of HF is imperative and should be optimized concurrently with the determination of AS-severity. Finally, AS should be treated according to guidelines, keeping in mind that HF and low-flow increase interventions risks.

Cardiac magnetic relaxometry versus ejection fraction in anthracycline-related cardiac changes: a systematic review and meta-analysis

PURPOSE

The purpose of this meta-analysis is to compare the magnitude of the changes in left ventricular ejection fraction (LVEF) and cardiac magnetic resonance (CMR) relaxometry techniques soon after the completion of anthracycline therapy. Anthracyclines are associated with myocardial functional and morphological changes. LVEF is currently used to identify the functional changes. Anthracyclines can also cause myocardial inflammation and oedema. This can be assessed using CMR relaxometry techniques; T1 and T2 mapping and extracellular volume (ECV) fraction.

METHODS

Three databases were systematically searched for studies evaluating CMR relaxometry parameter at baseline and 1±1 months after anthracycline completion (the last search date 17 March 2023). CMR parameters pre and post anthracycline-based chemotherapy were abstracted. A random effects model was used to pool mean difference (MD) in LVEF and ECV. Standardised mean difference (SMD) was also calculated for T1 and T2 mapping due to the variations in techniques, normal ranges and for the comparison among the parameters.

RESULTS

A total of 296 patients were included from 10 studies. 84% were female with a mean age of 54.9 years. Statistically significant alterations were observed in LVEF (MD -3.38% (95% CI -5.13%, -1.62%)) and ECV (1.92% (1.30%, 2.53%)). The pooled SMDs were also significant in LVEF, T1, T2 and ECV with -0.61 (-0.91, -0.30), 0.53 (0.16, 0.90), 0.59 (0.22, 0.96) and 0.74 (0.41, 1.06), respectively.

CONCLUSIONS

Our meta-analysis demonstrated small but significant alterations in CMR relaxometry parameters soon after anthracycline therapy, where ECV was superior to LVEF and T1 or T2 mapping. However, these short-term MDs were below the minimal detectable differences.

PROSPERO REGISTRATION NUMBER

CRD42020196296.

Quantitative assessment of radiotherapy-induced myocardial damage using MRI: a systematic review

PURPOSE

To determine the role of magnetic resonance imaging (MRI)-based metrics to quantify myocardial toxicity following radiotherapy (RT) in human subjects through review of current literature.

METHODS

Twenty-one MRI studies published between 2011-2022 were identified from available databases. Patients received chest irradiation with/without other treatments for various malignancies including breast, lung, esophageal cancer, Hodgkin's, and non-Hodgkin's lymphoma. In 11 longitudinal studies, the sample size, mean heart dose, and follow-up times ranged from 10-81 patients, 2.0-13.9 Gy, and 0-24 months after RT (in addition to a pre-RT assessment), respectively. In 10 cross-sectional studies, the sample size, mean heart dose, and follow-up times ranged from 5-80 patients, 2.1-22.9 Gy, and 2-24 years from RT completion, respectively. Global metrics of left ventricle ejection fraction (LVEF) and mass/dimensions of cardiac chambers were recorded, along with global/regional values of T1/T2 signal, extracellular volume (ECV), late gadolinium enhancement (LGE), and circumferential/radial/longitudinal strain.

RESULTS

LVEF tended to decline at >20 years follow-up and in patients treated with older RT techniques. Changes in global strain were observed after shorter follow-up (13±2 months) for concurrent chemoradiotherapy. In concurrent treatments with longer follow-up (8.3 years), increases in left ventricle (LV) mass index were correlated with LV mean dose. In pediatric patients, increases in LV diastolic volume were correlated with heart/LV dose at 2 years post-RT. Regional changes were observed earlier post-RT. Dose-dependent responses were reported for several parameters, including: increased T1 signal in high-dose regions, a 0.136% increase of ECV per Gy, progressive increase of LGE with increasing dose at regions receiving >30 Gy, and correlation between increases in LV scarring volume and LV mean/V10/V25 Gy dose.

CONCLUSION

Global metrics only detected changes over longer follow-up, in older RT techniques, in concurrent treatments, and in pediatric patients. In contrast, regional measurements detected myocardial damage at shorter follow-up and in RT treatments without concurrent treatment and had greater potential for dose-dependent response. The early detection of regional changes suggests the importance of regional quantification of RT-induced myocardial toxicity at early stages, before damage becomes irreversible. Further works with homogeneous cohorts are required to examine this matter.

Cardiac Magnetic Resonance Derived Left Ventricular Eccentricity Index and Right Ventricular Mass Measurements Predict Outcome in Children with Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is associated with increased right ventricular (RV) afterload, affecting RV remodeling and RV performance, a major determinant of outcome in PAH-patients. In children with PAH, treatment strategy is guided by risk stratification where noninvasive prognosticators are highly needed. The prognostic value of RV characteristics derived by cardiac magnetic resonance (CMR) has been scarcely studied in pediatric PAH. We aimed to identify CMR-derived morphometric and functional RV characteristics prognostic for outcome in children with PAH. From the Dutch National cohort, thirty-eight children with either idiopathic/heritable PAH (IPAH/HPAH) or PAH associated with congenital heart disease (PAH-CHD), who underwent CMR, were included (median (interquartile range) [IQR] age 13.0 years (10.8-15.0), 66% females). Patients had severe PAH, characterized by their World Health Organization Functional Class, increased N-terminal pro-B-type natriuretic peptide and high pulmonary arterial pressure and pulmonary vascular resistance index at time of CMR. RV-ejection fraction (RVEF), indexed RV-mass (RVMi), the ratio between RV and LV mass (RVM/LVM-ratio) and left ventricular eccentricity index (LVEI) all correlated with transplant-free survival from time of CMR. These correlations could not be confirmed in the PAH-CHD group. This study shows that CMR-derived measures reflecting RV function and remodeling (LVEI, RVMi, RVM/LVM-ratio, RVEF) predict transplant-free survival in children with IPAH/HPAH and may be included in risk stratification scores in pediatric PAH.

Prognostic Utility of Cardiac MRI Myocardial Strain Parameters in Patients With Ischemic and Nonischemic Dilated Cardiomyopathy: A Multicenter Study

BACKGROUND. Prior small single-center studies have yielded conflicting results regarding the prognostic significance of myocardial strain parameters derived from feature tracking (FT) on cardiac MRI in patients with dilated cardiomyopathy (DCM). OBJECTIVE. The purpose of this study was to evaluate the prognostic utility of FT parameters on cardiac MRI in patients with ischemic and nonischemic DCM and to determine the optimal strain parameter for outcome prediction. METHODS. This retrospective study included 471 patients (median age, 61 years; 365 men, 106 women) with ischemic (n = 233) or nonischemic (n = 238) DCM and left ventricular (LV) ejection fraction (EF) less than 50% who underwent cardiac MRI at any of four centers from January 2011 to December 2019. Cardiac MRI parameters were determined by manual contouring. In addition, software-based FT was used to calculate six myocardial strain parameters (LV and right ventricular [RV] global radial strain, global circumferential strain, and global longitudinal strain [GLS]). Late gadolinium enhancement (LGE) was also evaluated. Patients were assessed for a composite outcome of all-cause mortality and/or heart-failure hospitalization. Cox regression models were used to determine associations between strain parameters and the composite outcome. RESULTS. Mean LV EF was 27.5% and mean LV GLS was -6.9%. The median follow-up period was 1328 days. The composite outcome occurred in 220 patients (125 deaths, 95 heart-failure hospitalizations). All six myocardial strain parameters were significant independent predictors of the composite outcome (hazard ratio [HR] = 0.92-1.16; all p < .05). In multivariable models that included age, corrected LV and RV end-diastolic volume, LV and RV EF, and presence of LGE, the only strain parameter that was a significant independent predictor of the composite outcome was LV GLS (HR = 1.13, p = .006); LV EF and presence of LGE were not independent predictors of the composite outcome in the models (p > .05). A LV GLS threshold of -6.8% had sensitivity of 62.6% and specificity of 62.6% in predicting the composite outcome rate at 4.0 years. CONCLUSION. LV GLS, derived from FT on cardiac MRI, is a significant independent predictor of adverse outcomes in patients with DCM. CLINICAL IMPACT. This study strengthens the body of evidence supporting the clinical implementation of FT when performing cardiac MRI in patients with DCM.

Epicardial Adipose Tissue: A Piece of The Puzzle in Pediatric Hypertension

Background and purpose: Epicardial adipose tissue (EAT) is a metabolically active tissue located on the surface of the myocardium, which might have a potential impact on cardiac function and morphology. The aim of this study was to evaluate whether EAT is associated with essential arterial hypertension (AH) in children and adolescents. Methods: Prospective cardiovascular magnetic resonance (CMR) study and clinical evaluation were performed on 72 children, 36 of whom were diagnosed with essential AH, and the other 36 were healthy controls. The two groups were compared in volume and thickness of EAT, end-diastolic volume, end-systolic volume, stroke volume, left ventricular (LV) ejection fraction, average heart mass, average LV myocardial thickness, peak filling rate, peak filling time and clinical parameters. Results: Hypertensive patients have a higher volume (16.5 ± 1.9 cm3 and 10.9 ± 1.5 cm3 (t = −13.815, p < 0.001)) and thickness (0.8 ± 0.3 cm and 0.4 ± 0.1 cm, (U = 65.5, p < 0.001)) of EAT compared to their healthy peers. The volume of EAT might be a potential predictor of AH in children. Conclusions: Our study indicates that the volume of EAT is closely associated with hypertension in children and adolescents.

Impaired left-ventricular global longitudinal strain by feature-tracking cardiac MRI predicts mortality in systemic sclerosis

Impaired left-ventricular (LV) and right-ventricular (RV) cardiac magnetic resonance (CMR) strain has been documented in systemic sclerosis (SSc). However, it is unknown whether the CMR strain is predictive of adverse outcomes in SSc. Therefore, we set out to investigate the prognostic value of CMR strain in SSc. Patients with SSc who underwent CMR for clinical indications between 11/2010 and 07/2020 were retrospectively studied. LV and RV strain was evaluated by feature tracking. The association between strain, late gadolinium enhancement (LGE), and survival was evaluated with time to event and Cox-regression analyses. During the study period, 42 patients with SSc (age: 57 ± 14 years, 83% female, 57% limited cutaneous SSc, SSc duration: 7 ± 8 years) underwent CMR. During the median follow-up of 3.6 years, 11 patients died (26%). Compared to surviving patients, patients who died had significantly worse LV GLS (- 8.2 ± 6.2% versus - 12.1 ± 2.9%, p = 0.03), but no difference in LV global radial, circumferential, or RV strain values. Patients within the quartile of most impaired LV GLS (≥ - 12.8%, n = 10) had worse survival when compared to patients with preserved LV GLS (< - 12.8%, n = 32, log-rank p = 0.02), which persisted after controlling for LV cardiac output, LV cardiac index, reduced LV ejection fraction, or presence of LGE. In addition, patients who had both impaired LV GLS and LGE (n = 5) had worse survival than patients with LGE or impaired GLS alone (n = 14) and compared to those without any of these features (n = 17, p = 0.003). In our retrospective cohort of patients with SSc undergoing CMR for clinical indications, LV GLS and LGE were found to be predictive of overall survival.

Quantification of left atrial function by the area-length method overestimates left atrial emptying fraction

PURPOSE

The biplane area-length method is commonly used in cardiac magnetic resonance (CMR) to assess left atrial (LA) volume (LAV) and function. Associations between left atrial emptying fraction (LAEF) and clinical outcomes have been reported. However, only limited data are available on the calculation of LAEF using the biplane method compared to 3D assessment. This study aimed to compare volumetric and functional LA parameters obtained from the biplane method with 3D assessment in a large, multiethnic cohort.

METHOD

158 participants of MESA (Multi-Ethnic Study of Atherosclerosis) underwent CMR that included standard two- and four-chamber steady-state free precession (SSFP) cine imaging for the biplane method. For 3D-based assessment, short-axis SSFP cine series covering the entire LA were obtained, followed by manual delineation of LA contours to create a time-resolved 3D LAV dataset. Paired t-tests and Bland-Altman plots were used to analyze the data.

RESULTS

Standard volumetric assessment showed that LAVmin (bias: -8.35 mL, p < 0.001), LAVmax (bias: -9.38 mL, p < 0.001) and LAVpreA (bias: -10.27 mL, p < 0.001) were significantly smaller using the biplane method compared to 3D assessment. Additionally, the biplane method reported significantly higher LAEFtotal (bias: 7.22 %, p < 0.001), LAEFactive (bias: 6.08 %, p < 0.001), and LAEFpassive (bias: 4.51 %, p < 0.001) with wide limits of agreement.

CONCLUSIONS

LA volumes were underestimated using the biplane method compared to 3D assessment, while LAEF parameters were overestimated. These findings demonstrate a lack of precision using the biplane method for LAEF assessment. Our results support the usage of 3D assessment in specific settings when LA volumetric and functional parameters are in focus.

Utility of cardiovascular magnetic resonance in patients with stable troponin elevation

AIMS

Cardiovascular magnetic resonance (CMR) imaging has a potential role in the evaluation of symptomatic patients with stable troponin elevation; however, its utility remains unexplored. We sought to determine the incremental diagnostic value of CMR in this unique cohort and assess the long-term clinical outcomes.

METHODS AND RESULTS

Two hundred twenty-five consecutive patients presenting with cardiac chest pain/dyspnoea, stable troponin elevation, and undergoing CMR assessment were identified retrospectively from registry database. The study cohort was prospectively followed for major adverse cardiac events (MACEs) (defined as composite of all-cause mortality and cardiovascular readmissions). The primary outcome measure was the diagnostic utility of CMR, i.e. percentage of patients for whom CMR identified the cause of stable troponin elevation. Secondary outcome measures included the incremental value of CMR and occurrence of MACE. CMR was able to identify the cause for stable troponin elevation in 160 (71%) patients. A normal CMR was identified in 17% and an inconclusive CMR in 12% of the patients. CMR changed the referral diagnosis in 59 (26%) patients. Utilizing a baseline prediction model (pre-CMR referral diagnosis), the net reclassification index was 0.11 and integrated discriminatory improvement index measured 0.33 following CMR. Over a median follow-up of 4.3 years (interquartile range 2.8-6.3), 72 (32%) patients experienced MACE.

CONCLUSION

CMR identified a cause for stable troponin elevation in 7 of 10 cases, and a new diagnosis was evident in 1 of 4 cases. CMR improved the net reclassification of patients with stable troponin elevation.

Dynamic pressure-volume loop analysis by simultaneous real-time cardiovascular magnetic resonance and left heart catheterization

BACKGROUND

Left ventricular (LV) contractility and compliance are derived from pressure-volume (PV) loops during dynamic preload reduction, but reliable simultaneous measurements of pressure and volume are challenging with current technologies. We have developed a method to quantify contractility and compliance from PV loops during a dynamic preload reduction using simultaneous measurements of volume from real-time cardiovascular magnetic resonance (CMR) and invasive LV pressures with CMR-specific signal conditioning.

METHODS

Dynamic PV loops were derived in 16 swine (n = 7 naïve, n = 6 with aortic banding to increase afterload, n = 3 with ischemic cardiomyopathy) while occluding the inferior vena cava (IVC). Occlusion was performed simultaneously with the acquisition of dynamic LV volume from long-axis real-time CMR at 0.55 T, and recordings of invasive LV and aortic pressures, electrocardiogram, and CMR gradient waveforms. PV loops were derived by synchronizing pressure and volume measurements. Linear regression of end-systolic- and end-diastolic- pressure-volume relationships enabled calculation of contractility. PV loops measurements in the CMR environment were compared to conductance PV loop catheter measurements in 5 animals. Long-axis 2D LV volumes were validated with short-axis-stack images.

RESULTS

Simultaneous PV acquisition during IVC-occlusion was feasible. The cardiomyopathy model measured lower contractility (0.2 ± 0.1 mmHg/ml vs 0.6 ± 0.2 mmHg/ml) and increased compliance (12.0 ± 2.1 ml/mmHg vs 4.9 ± 1.1 ml/mmHg) compared to naïve animals. The pressure gradient across the aortic band was not clinically significant (10 ± 6 mmHg). Correspondingly, no differences were found between the naïve and banded pigs. Long-axis and short-axis LV volumes agreed well (difference 8.2 ± 14.5 ml at end-diastole, -2.8 ± 6.5 ml at end-systole). Agreement in contractility and compliance derived from conductance PV loop catheters and in the CMR environment was modest (intraclass correlation coefficient 0.56 and 0.44, respectively).

CONCLUSIONS

Dynamic PV loops during a real-time CMR-guided preload reduction can be used to derive quantitative metrics of contractility and compliance, and provided more reliable volumetric measurements than conductance PV loop catheters.

4D-flow MRI derived wall shear stress for the risk stratification of bicuspid aortic valve aortopathy: A systematic review

Purpose

Current intervention guidelines for bicuspid aortic valve (BAV) associated ascending aorta (AAo) dilatation are suboptimal predictors of clinical outcome. There is growing interest in identifying better biomarkers such as wall shear stress (WSS) to help risk stratify BAV aortopathy. The aim of the systematic review is to synthesize existing evidence of the relationship between WSS and aortopathy in the BAV population.

Methods

A comprehensive literature search of available major databases was performed in May 2022 to include studies that used four-dimensional flow cardiac magnetic resonance (4D-flow) MRI to quantify WSS in the AAo in adult BAV populations. Summary results and statistical analysis were provided for key numerical results. A narrative summary was provided to assess similarities between studies.

Results

A total of 26 studies that satisfied selection criteria and quality assessment were included in the review. The presence of BAV resulted in significantly elevated WSS magnitude and circumferential WSS, but not axial WSS. The presence of aortic stenosis had additional impact on WSS and flow alterations. BAV phenotypes were associated with different WSS distributions and flow profiles. Altered protein expression in the AAo wall associated with WSS supported the contribution of altered hemodynamics to aortopathy in addition to genetic factors.

Conclusion

WSS has the potential to be a valid biomarker for BAV aortopathy. Future work would benefit from larger study cohorts with longitudinal evaluations to further characterize WSS association with aortopathy, mortality, and morbidities.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022337077, identifier CRD42022337077.

Signal intensity informed multi-coil encoding operator for physics-guided deep learning reconstruction of highly accelerated myocardial perfusion CMR

PURPOSE

To develop a physics-guided deep learning (PG-DL) reconstruction strategy based on a signal intensity informed multi-coil (SIIM) encoding operator for highly-accelerated simultaneous multislice (SMS) myocardial perfusion cardiac MRI (CMR).

METHODS

First-pass perfusion CMR acquires highly-accelerated images with dynamically varying signal intensity/SNR following the administration of a gadolinium-based contrast agent. Thus, using PG-DL reconstruction with a conventional multi-coil encoding operator leads to analogous signal intensity variations across different time-frames at the network output, creating difficulties in generalization for varying SNR levels. We propose to use a SIIM encoding operator to capture the signal intensity/SNR variations across time-frames in a reformulated encoding operator. This leads to a more uniform/flat contrast at the output of the PG-DL network, facilitating generalizability across time-frames. PG-DL reconstruction with the proposed SIIM encoding operator is compared to PG-DL with conventional encoding operator, split slice-GRAPPA, locally low-rank (LLR) regularized reconstruction, low-rank plus sparse (L + S) reconstruction, and regularized ROCK-SPIRiT.

RESULTS

Results on highly accelerated free-breathing first pass myocardial perfusion CMR at three-fold SMS and four-fold in-plane acceleration show that the proposed method improves upon the reconstruction methods use for comparison. Substantial noise reduction is achieved compared to split slice-GRAPPA, and aliasing artifacts reduction compared to LLR regularized reconstruction, L + S reconstruction and PG-DL with conventional encoding. Furthermore, a qualitative reader study indicated that proposed method outperformed all methods.

CONCLUSION

PG-DL reconstruction with the proposed SIIM encoding operator improves generalization across different time-frames /SNRs in highly accelerated perfusion CMR.

Cardiac Multimodality Imaging in Hypertrophic Cardiomyopathy: What to Look for and When to Image

Hypertrophic cardiomyopathy (HCM), now recognized as a common cardiomyopathy of complex genomics and pathophysiology, is defined by the presence of left ventricular hypertrophy of various morphologies and severity, significant hemodynamic consequences, and diverse phenotypic, both structural and clinical, profiles. Advancements in cardiac multimodality imaging, including echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography, with and without angiography have greatly improved the diagnosis of HCM, and enable precise measurements of cardiac mass, volume, wall thickness, function, and physiology. Multimodality imaging provides comprehensive and complementary information and hasemerged as the bedrock for the diagnosis, clinical assessment, serial monitoring, and sudden cardiac death risk stratification of patients with HCM. This review highlights the role of cardiac multimodality imaging in the modern diagnosis and management of HCM.

Comparison of Demographic, Clinical, Biochemical, and Imaging Findings in Hypertrophic Cardiomyopathy Prognosis: A Network Meta-Analysis

BACKGROUND

Despite hypertrophic cardiomyopathy (HCM) being the most common inherited heart disease and conferring increased risk for heart failure (HF) and sudden cardiac death (SCD), risk assessment in HCM patients is still largely unresolved.

OBJECTIVES

This study aims to synthesize and compare the prognostic impact of demographic, clinical, biochemical, and imaging findings in patients with HCM.

METHODS

The authors searched PubMed, Embase, and Cochrane Library for studies published from 1955 to November 2020, and the endpoints were: 1) all-cause death; 2) an arrhythmic endpoint including SCD, sustained ventricular tachycardia, ventricular fibrillation, or aborted SCD; and 3) a composite endpoint including (1) or (2) plus hospitalization for HF or cardiac transplantation. The authors performed a pairwise meta-analysis obtaining the pooled estimate separately for the association between baseline variables and study endpoints. A random-effects network meta-analysis was subsequently used to comparatively assess the prognostic value of outcome associates.

RESULTS

A total of 112 studies with 58,732 HCM patients were included. Among others, increased brain natriuretic peptide/N-terminal pro-B-type natriuretic peptide, late gadolinium enhancement (LGE), positive genotype, impaired global longitudinal strain, and presence of apical aneurysm conferred increased risk for the composite endpoint. At network meta-analysis, LGE showed the highest prognostic value for all endpoints and was superior to all other associates except New York Heart Association functional class >class II. A multiparametric imaging-based model was superior in predicting the composite endpoint compared to a prespecified model based on conventional risk factors.

CONCLUSIONS

This network meta-analysis supports the development of multiparametric risk prediction algorithms, including advanced imaging markers additively to conventional risk factors, for refined risk stratification in HCM. (Long-term prognosis of hypertrophic cardiomyopathy according to genetic, clinical, biochemical and imaging findings: a systemic review and meta-analysis; CRD42020185219).

Maternal Cardiac Changes in Women With Obesity and Gestational Diabetes Mellitus

OBJECTIVE

We investigated if women with gestational diabetes mellitus (GDM) in the third trimester of pregnancy exhibit adverse cardiac alterations in myocardial energetics, function, or tissue characteristics.

RESEARCH DESIGN AND METHODS

Thirty-eight healthy, pregnant women and 30 women with GDM were recruited. Participants underwent phosphorus MRS and cardiovascular magnetic resonance for assessment of myocardial energetics (phosphocreatine [PCr] to ATP ratio), tissue characteristics, biventricular volumes and ejection fractions, left ventricular (LV) mass, global longitudinal shortening (GLS), and mitral in-flow E-wave to A-wave ratio.

RESULTS

Participants were matched for age, gestational age, and ethnicity. The following data are reported as mean ± SD. The women with GDM had higher BMI (27 ± 4 vs. 33 ± 5 kg/m2; P = 0.0001) and systolic (115 ± 11 vs. 121 ± 13 mmHg; P = 0.04) and diastolic (72 ± 7 vs. 76 ± 9 mmHg; P = 0.04) blood pressures. There was no difference in N-terminal pro-brain natriuretic peptide concentrations between the groups. The women with GDM had lower myocardial PCr to ATP ratio (2.2 ± 0.3 vs. 1.9 ± 0.4; P < 0.0001), accompanied by lower LV end-diastolic volumes (76 ± 12 vs. 67 ± 11 mL/m2; P = 0.002) and higher LV mass (90 ± 13 vs. 103 ± 18 g; P = 0.001). Although ventricular ejection fractions were similar, the GLS was reduced in women with GDM (-20% ± 3% vs. -18% ± 3%; P = 0.008).

CONCLUSIONS

Despite no prior diagnosis of diabetes, women with obesity and GDM manifest impaired myocardial contractility and higher LV mass, associated with reductions in myocardial energetics in late pregnancy compared with lean women with healthy pregnancy. These findings may aid our understanding of the long-term cardiovascular risks associated with GDM.

The Role of Artificial Intelligence in Predicting Outcomes by Cardiovascular Magnetic Resonance: A Comprehensive Systematic Review

Background and Objectives: Interest in artificial intelligence (AI) for outcome prediction has grown substantially in recent years. However, the prognostic role of AI using advanced cardiac magnetic resonance imaging (CMR) remains unclear. This systematic review assesses the existing literature on AI in CMR to predict outcomes in patients with cardiovascular disease. Materials and Methods: Medline and Embase were searched for studies published up to November 2021. Any study assessing outcome prediction using AI in CMR in patients with cardiovascular disease was eligible for inclusion. All studies were assessed for compliance with the Checklist for Artificial Intelligence in Medical Imaging (CLAIM). Results: A total of 5 studies were included, with a total of 3679 patients, with 225 deaths and 265 major adverse cardiovascular events. Three methods demonstrated high prognostic accuracy: (1) three-dimensional motion assessment model in pulmonary hypertension (hazard ratio (HR) 2.74, 95%CI 1.73−4.34, p < 0.001), (2) automated perfusion quantification in patients with coronary artery disease (HR 2.14, 95%CI 1.58−2.90, p < 0.001), and (3) automated volumetric, functional, and area assessment in patients with myocardial infarction (HR 0.94, 95%CI 0.92−0.96, p < 0.001). Conclusion: There is emerging evidence of the prognostic role of AI in predicting outcomes for three-dimensional motion assessment in pulmonary hypertension, ischaemia assessment by automated perfusion quantification, and automated functional assessment in myocardial infarction.