T1 Mapping and Extracellular Volume Fraction in Dilated Cardiomyopathy: A Prognosis Study

Integration of Cine-cardiac Magnetic Resonance Radiomics and Machine Learning for Differentiating Ischemic and Dilated Cardiomyopathy

RATIONALE AND OBJECTIVES

This study aims to evaluate the capability of machine learning algorithms in utilizing radiomic features extracted from cine-cardiac magnetic resonance (CMR) sequences for differentiating between ischemic cardiomyopathy (ICM) and dilated cardiomyopathy (DCM).

MATERIALS AND METHODS

This retrospective study included 115 cardiomyopathy patients subdivided into ICM (n = 64) and DCM cohorts (n = 51). We collected invasive clinical (IC), noninvasive clinical (NIC), and combined clinical (CC) feature subsets. Radiomic features were extracted from regions of interest (ROIs) in the left ventricle (LV), LV cavity (LVC), and myocardium (MYO). We tested 10 classical machine learning classifiers and validated them through fivefold cross-validation. We compared the efficacy of clinical feature-based models and radiomics-based models to identify the superior diagnostic approach.

RESULTS

In the validation set, the Gaussian naive Bayes (GNB) model outperformed the other models in all categories, with areas under the curve (AUCs) of 0.879 for IC_GNB, 0.906 for NIC_GNB, and 0.906 for CC_GNB. Among the radiomics models, the MYO_LASSOCV_MLP model demonstrated the highest AUC (0.919). In the test set, the MYO_RFECV_GNB radiomics model achieved the highest AUC (0.857), surpassing the performance of the three clinical feature models (IC_GNB: 0.732; NIC_GNB: 0.75; CC_GNB: 0.786).

CONCLUSION

Radiomics models leveraging MYO images from cine-CMR exhibit promising potential for differentiating ICM from DCM, indicating the significant clinical application scope of such models.

CLINICAL RELEVANCE STATEMENT

The integration of radiomics models and machine learning methods utilizing cine-CMR sequences enhances the diagnostic capability to distinguish between ICM and DCM, minimizes examination risks for patients, and potentially reduces the duration of medical imaging procedures.

A novel cardiac magnetic resonance-based personalized risk stratification model in dilated cardiomyopathy: a prospective study

OBJECTIVES

To explore individual weight of cardiac magnetic resonance (CMR) metrics to predict mid-term outcomes in patients with dilated cardiomyopathy (DCM), and develop a risk algorithm for mid-term outcome based on CMR biomarkers.

MATERIALS AND METHODS

Patients with DCM who underwent CMR imaging were prospectively enrolled in this study. The primary endpoint was a composite of heart failure (HF) death, sudden cardiac death (SCD), aborted SCD, and heart transplantation.

RESULTS

A total of 407 patients (age 48.1 ± 13.8 years, 331 men) were included in the final analysis. During a median follow-up of 21.7 months, 63 patients reached the primary endpoint. NYHA class III/IV (HR = 2.347 [1.073-5.133], p = 0.033), left ventricular ejection fraction (HR = 0.940 [0.909-0.973], p < 0.001), late gadolinium enhancement (LGE) > 0.9% and ≤ 6.6% (HR = 3.559 [1.020-12.412], p = 0.046), LGE > 6.6% (HR = 6.028 [1.814-20.038], p = 0.003), and mean extracellular volume (ECV) fraction ≥ 32.8% (HR = 5.922 [2.566-13.665], p < 0.001) had a significant prognostic association with the primary endpoints (C-statistic: 0.853 [0.810-0.896]). Competing risk regression analyses showed that patients with mean ECV fraction ≥ 32.8%, LGE ≥ 5.9%, global circumferential strain ≥ - 5.6%, or global longitudinal strain ≥ - 7.3% had significantly shorter event-free survival due to HF death and heart transplantation. Patients with mean ECV fraction ≥ 32.8% and LGE ≥ 5.9% had significantly shorter event-free survival due to SCD or aborted SCD.

CONCLUSION

ECV fraction may be the best independently risk factor for the mid-term outcomes in patients with DCM, surpassing LVEF and LGE. LGE has a better prognostic value than other CMR metrics for SCD and aborted SCD. The risk stratification model we developed may be a promising non-invasive tool for decision-making and prognosis.

CLINICAL RELEVANCE STATEMENT

"One-stop" assessment of cardiac function and myocardial characterization using cardiac magnetic resonance might improve risk stratification of patients with DCM. In this prospective study, we propose a novel risk algorithm in DCM including NYHA functional class, LVEF, LGE, and ECV.

KEY POINTS

• The present study explores individual weight of CMR metrics for predicting mid-term outcomes in dilated cardiomyopathy. • We have developed a novel risk algorithm for dilated cardiomyopathy that includes cardiac functional class, ejection fraction, late gadolinium enhancement, and extracellular volume fraction. • Personalized risk model derived by CMR contributes to clinical assessment and individual decision-making.

Cardiac magnetic resonance in advanced heart failure

Heart failure (HF) is a chronic and progressive disease that often progresses to an advanced stage where conventional therapy is insufficient to relieve patients' symptoms. Despite the availability of advanced therapies such as mechanical circulatory support or heart transplantation, the complexity of defining advanced HF, which requires multiple parameters and multimodality assessment, often leads to delays in referral to dedicated specialists with the result of a worsening prognosis. In this review, we aim to explore the role of cardiac magnetic resonance (CMR) in advanced HF by showing how CMR is useful at every step in managing these patients: from diagnosis to prognostic stratification, hemodynamic evaluation, follow-up and advanced therapies such as heart transplantation. The technical challenges of scanning advanced HF patients, which often require troubleshooting of intracardiac devices and dedicated scans, will be also discussed.

Safety of Continuing Trastuzumab for Mild Cardiotoxicity: A Cardiovascular Magnetic Resonance Imaging Study

The safety of continuing human epidermal growth factor receptor 2 (HER2)-targeted therapy in women with mild cardiotoxicity remains unclear. We performed a retrospective matched cohort study of 14 patients with human epidermal growth factor receptor 2-positive breast cancer receiving sequential anthracycline and trastuzumab therapy, nested within the Evaluation of Myocardial Changes During Breast Adenocarcinoma Therapy to Detect Cardiotoxicity Earlier With MRI (EMBRACE-MRI) trial. Among patients who developed cardiotoxicity and were treated with heart failure therapy, we compared those who had trastuzumab therapy interrupted to a matched cohort who continued trastuzumab therapy. By a median of 2.5 years of follow-up, no significant differences were present between the groups in the proportion with magnetic resonance imaging-measured left ventricular ejection fraction < 40%, magnetic resonance imaging-measured left ventricular volumes, left ventricular ejection fraction, edema, fibrotic markers, cardiopulmonary fitness, or quality of life.

Multiparametric Mapping via Cardiovascular Magnetic Resonance in the Risk Stratification of Ventricular Arrhythmias and Sudden Cardiac Death

Risk stratification for malignant ventricular arrhythmias and sudden cardiac death is a daunting task for physicians in daily practice. Multiparametric mapping sequences obtained via cardiovascular magnetic resonance imaging can improve the risk stratification for malignant ventricular arrhythmias by unveiling the presence of pathophysiological pro-arrhythmogenic processes. However, their employment in clinical practice is still restricted. The present review explores the current evidence supporting the association between mapping abnormalities and the risk of ventricular arrhythmias in several cardiovascular diseases. The key message is that further clinical studies are needed to test the additional value of mapping techniques beyond conventional cardiovascular magnetic resonance imaging for selecting patients eligible for an implantable cardioverter defibrillator.

Correlation of extent of left ventricular endocardial unipolar low-voltage zones with ventricular tachycardia in nonischemic cardiomyopathy

BACKGROUND

Endocardial electrogram (EGM) characteristics in nonischemic cardiomyopathy (NICM) have not been explored adequately for prognostication.

OBJECTIVE

We aimed to study correlation of bipolar and unipolar EGM characteristics with left ventricular ejection fraction (LVEF) and ventricular tachycardia (VT) in NICM.

METHODS

Electroanatomic mapping of the left ventricle was performed. EGM characteristics were correlated with LVEF. Differences between groups with and without VT and predictors of VT were studied.

RESULTS

In 43 patients, unipolar EGM variables had better correlation with baseline LVEF than bipolar EGM variables: unipolar voltage (r = +0.36), peak negative unipolar voltage (r = -0.42), peak positive unipolar voltage (r = +0.38), and percentage area of unipolar low-voltage zone (LVZ; r = -0.41). Global mean unipolar voltage (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), extent of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3), and percentage area of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3) were significant predictors of VT. For classification of patients with VT, extent of unipolar LVZ had an area under the curve of 0.82 (95% CI, 0.69-0.95; P < .001), and percentage area of unipolar LVZ had an area under the curve of 0.83 (95% CI, 0.71-0.96; P = .01). Cutoff of >3 segments for extent of unipolar LVZ had the best diagnostic accuracy (sensitivity, 90%; specificity, 67%) and cutoff of 33% for percentage area of unipolar LVZ had the best diagnostic accuracy (sensitivity, 95%; specificity, 60%) for VT.

CONCLUSION

In NICM, extent and percentage area of unipolar LVZs are significant predictors of VT. Cutoffs of >3 segments of unipolar LVZ and >33% area of unipolar LVZ have good diagnostic accuracies for association with VT.

Imagenetics for Precision Medicine in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a common heart muscle disorder of nonischemic etiology associated with heart failure development and the risk of malignant ventricular arrhythmias and sudden cardiac death. A tailored approach to risk stratification and prevention of sudden cardiac death is required in genetic DCM given its variable presentation and phenotypic severity. Currently, advances in cardiogenetics have shed light on disease mechanisms, the complex genetic architecture of DCM, polygenic contributors to disease susceptibility and the role of environmental triggers. Parallel advances in imaging have also enhanced disease recognition and the identification of the wide spectrum of phenotypes falling under the DCM umbrella. Genotype-phenotype associations have been also established for specific subtypes of DCM, such as DSP (desmoplakin) or FLNC (filamin-C) cardiomyopathy but overall, they remain elusive and not readily identifiable. Also, despite the accumulated knowledge on disease mechanisms, certain aspects remain still unclear, such as which patients with DCM are at risk for disease progression or remission after treatment. Imagenetics, that is, the combination of imaging and genetics, is expected to further advance research in the field and contribute to precision medicine in DCM management and treatment. In the present article, we review the existing literature in the field, summarize the established knowledge and emerging data on the value of genetics and imaging in establishing genotype-phenotype associations in DCM and in clinical decision making for DCM patients.

Efficacy of Native T1 Mapping for Patients With Non-Ischemic Cardiomyopathy and Ventricular Functional Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

BACKGROUND

We investigated the efficacy of left ventricular (LV) myocardial damage by native T1mapping obtained with cardiac magnetic resonance (CMR) for patients undergoing transcatheter edge-to-edge repair (TEER).Methods and Results: We studied 40 symptomatic non-ischemic heart failure (HF) patients and ventricular functional mitral regurgitation (VFMR) undergoing TEER. LV myocardial damage was defined as the native T1Z-score, which was converted from native T1values obtained with CMR. The primary endpoint was defined as HF rehospitalization or cardiovascular death over 12 months after TEER. Multivariable Cox proportional hazards analysis showed that the native T1Z-score was the only independent parameter associated with cardiovascular events (hazard ratio 3.40; 95% confidential interval 1.51-7.67), and that patients with native T1Z-scores <2.41 experienced significantly fewer cardiovascular events than those with native T1Z-scores ≥2.41 (P=0.001). Moreover, the combination of a native T1Z-score <2.41 and more severe VFMR (effective regurgitant orifice area [EROA] ≥0.30 cm2) was associated with fewer cardiovascular events than a native T1Z-score ≥2.41 and less severe VFMR (EROA <0.30 cm2; P=0.002).

CONCLUSIONS

Assessment of baseline LV myocardial damage based on native T1Z-scores obtained with CMR without gadolinium-based contrast media is a valuable additional parameter for better management of HF patients and VFMR following TEER.

HTRA1-driven detachment of type I collagen from endoplasmic reticulum contributes to myocardial fibrosis in dilated cardiomyopathy

BACKGROUND

The aberrant secretion and excessive deposition of type I collagen (Col1) are important factors in the pathogenesis of myocardial fibrosis in dilated cardiomyopathy (DCM). However, the precise molecular mechanisms underlying the synthesis and secretion of Col1 remain unclear.

METHODS AND RESULTS

RNA-sequencing analysis revealed an increased HtrA serine peptidase 1 (HTRA1) expression in patients with DCM, which is strongly correlated with myocardial fibrosis. Consistent findings were observed in both human and mouse tissues by immunoblotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunohistochemistry, and immunofluorescence analyses. Pearson's analysis showed a markedly positive correlation between HTRA1 level and myocardial fibrosis indicators, including extracellular volume fraction (ECV), native T1, and late gadolinium enhancement (LGE), in patients with DCM. In vitro experiments showed that the suppression of HTRA1 inhibited the conversion of cardiac fibroblasts into myofibroblasts and decreased Col1 secretion. Further investigations identified the role of HTRA1 in promoting the formation of endoplasmic reticulum (ER) exit sites, which facilitated the transportation of Col1 from the ER to the Golgi apparatus, thereby increasing its secretion. Conversely, HTRA1 knockdown impeded the retention of Col1 in the ER, triggering ER stress and subsequent induction of ER autophagy to degrade misfolded Col1 and maintain ER homeostasis. In vivo experiments using adeno-associated virus-serotype 9-shHTRA1-green fluorescent protein (AAV9-shHTRA1-GFP) showed that HTRA1 knockdown effectively suppressed myocardial fibrosis and improved left ventricular function in mice with DCM.

CONCLUSIONS

The findings of this study provide valuable insights regarding the treatment of DCM-associated myocardial fibrosis and highlight the therapeutic potential of targeting HTRA1-mediated collagen secretion.

Current Insights and Novel Cardiovascular Magnetic Resonance-Based Techniques in the Prognosis of Non-Ischemic Dilated Cardiomyopathy

Cardiac magnetic resonance (CMR) imaging has an important emerging role in the evaluation and management of patients with cardiomyopathies, especially in patients with dilated cardiomyopathy (DCM). It allows a non-invasive characterization of myocardial tissue, thus assisting early diagnosis and precise phenotyping of the different cardiomyopathies, which is an essential step for early and individualized treatment of patients. Using imaging techniques such as late gadolinium enhancement (LGE), standard and advanced quantification as well as quantitative mapping parameters, CMR-based tissue characterization is useful in the differential diagnosis of DCM and risk stratification. The purpose of this article is to review the utility of CMR in the diagnosis and management of idiopathic DCM, as well as risk prediction and prognosis based on standard and emerging CMR contrast and non-contrast techniques. This is consistent with current evidence and guidance moving beyond traditional prognostic markers such as ejection fraction.

Novel Magnetic Resonance Imaging Tools for Hypertrophic Cardiomyopathy Risk Stratification

Hypertrophic cardiomyopathy (HCM) is a common genetic disorder with a well described risk of sudden cardiac death; however, risk stratification has remained a challenge. Recently, novel parameters in cardiac magnetic resonance imaging (CMR) have shown promise in helping to improve upon current risk stratification paradigms. In this manuscript, we have reviewed novel CMR risk markers and their utility in HCM. The results of the review showed that T1, extracellular volume, CMR feature tracking, and other miscellaneous novel CMR variables have the potential to improve sudden death risk stratification and may have additional roles in diagnosis and prognosis. The strengths and weaknesses of these imaging techniques, and their potential utility and implementation in HCM risk stratification are discussed.

Myocardial involvement characteristics by cardiac MR imaging in neurological and non-neurological Wilson disease patients

OBJECTIVES

To explore the characteristics of myocardial involvement in Wilson Disease (WD) patients by cardiac magnetic resonance (CMR).

METHODS

We prospectively included WD patients and age- and sex-matched healthy population. We applied CMR to analyze cardiac function, strain, T1 maps, T2 maps, extracellular volume fraction (ECV) maps, and LGE images. Subgroup analyzes were performed for patients with WD with predominantly neurologic manifestations (WD-neuro +) or only hepatic manifestations (WD-neuro -).

RESULTS

Forty-one WD patients (age 27.9 ± 8.0 years) and 40 healthy controls (age 25.4 ± 2.9 years) were included in this study. Compared to controls, the T1, T2, and ECV values were significantly increased in the WD group (T1 1085.1 ± 39.1 vs. 1046.5 ± 33.1 ms, T2 54.2 ± 3.3 ms vs. 51.5 ± 2.6 ms, ECV 31.8 ± 3.6% vs. 24.3 ± 3.7%) (all p < 0.001). LGE analysis revealed that LGE in WD patients was predominantly localized to the right ventricular insertion point and interventricular septum. Furthermore, the WD-neuro + group showed more severe myocardial damage compared to WD-neuro - group. The Unified Wilson Disease Rating Scale score was significantly correlated with ECV (Pearson's r = 0.64, p < 0.001).

CONCLUSIONS

CMR could detect early myocardial involvement in WD patients without overt cardiac function dysfunction. Furthermore, characteristics of myocardial involvement were different between WD-neuro + and WD-neuro - , and myocardial involvement might be more severe in WD-neuro + patients.

CRITICAL RELEVANCE STATEMENT

Cardiac magnetic resonance enables early detection of myocardial involvement in Wilson disease patients, contributing to the understanding of distinct myocardial characteristics in different subgroups and potentially aiding in the assessment of disease severity.

KEY POINTS

• CMR detects WD myocardial involvement with increased T1, T2, ECV. • WD-neuro + patients show more severe myocardial damage and correlation with ECV. • Differences of myocardial characteristics exist between WD-neuro + and WD-neuro - patients.

Adenosine Triphosphate Stress Myocardial Strain in Ischemic Heart Disease: An Animal Study with Histological Validation

RATIONALE AND OBJECTIVES

It is still challenging for cardiac magnetic resonance (CMR) to detect ischemic heart disease (IHD) without the use of gadolinium contrast. We aimed to evaluate the potential value of adenosine triphosphate (ATP) stress myocardial strain derived from feature tracking (FT) as a novel method for detecting IHD in a swine model.

MATERIALS AND METHODS

CMR cines, myocardial perfusion imaging at rest and during ATP stress, and late gadolinium enhancement were obtained in both control and IHD swine. Normal, remote, ischemic, and infarcted myocardium were analyzed. The diagnostic accuracy of myocardial strain for infarction and ischemia was assessed using coronary angiography and pathology as reference.

RESULTS

Eleven IHD swine and five healthy control swine were enrolled in this study. Strain parameters, even at rest, were associated with myocardial ischemia and infarction(all p < 0.05). The area under receiver operating characteristic curve (AUC) values of all strain parameters for detecting infarcted myocardium exceeded 0.900 (all p < 0.05). The AUC values for detecting ischemic myocardium were as follows: 0.906 and 0.847 for stress and rest radial strain, 0.763 and 0.716 for stress and rest circumferential strain, 0.758 and 0.663 for stress and rest longitudinal strain (all p < 0.001). Heat maps demonstrated that all strain parameters showed mild to moderate correlations with the stress myocardial blood flow and myocardial perfusion reserve (all p < 0.05).

CONCLUSION

CMR-FT-derived ATP stress myocardial strain shows promise as a noninvasive method for detecting myocardial ischemia and infarction in an IHD swine model, with rest strain parameters offering potential as a needle-free diagnostic option.

Entropy as a novel predictor of cardiovascular events in patients with left ventricular noncompaction

BACKGROUND

The risk stratification of left ventricular noncompaction (LVNC) remains ambiguous. LV entropy derived from late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) as a novel measurement of myocardial heterogeneity may serve as the substrate of major adverse cardiovascular events (MACEs). This retrospective study aimed to investigate the value of LV entropy for predicting MACEs in LVNC patients.

METHODS

Consecutive patients who underwent CMR and met the diagnosis criteria of LVNC were included. All patients were follow-up for MACEs (cardiac death, ventricular arrhythmia requiring therapy or heart failure hospitalization), and their LV entropy derived from the distribution of pixel signal intensities in the LGE of the LV myocardium was analyzed.

RESULTS

One hundred and forty-three patients (mean age 40 years, 64.3% male) were followed for a median of 3.2 years, and forty-two (29.4%) experienced MACEs. Presenting of symptoms, left ventricular end-diastolic diameter (LVEDD), LV end-diastolic volume (LVEDV) index, LV end-systolic volume (LVESV) index, LV ejection fraction (LVEF), LGE extent, and LV entropy showed association with MACEs. LV entropy maintained independent association with MACEs (HR: 4.76, 95%CI 3.68-5.15, p < 0.001) in multivariable analysis. Entropy was also strong independent predictor of MACEs in patients with and without LGE (HR: 5.89, 95% CI4.18-7.73, p < 0.001; HR: 3.06, 95% CI:1.53-4.80, p = 0.013, respectively).

CONCLUSIONS

LV entropy can predict MACEs in LVNC patients and provide incremental prognostic value on top of LVEF and LGE. Also, LV entropy may help risk stratification in LGE-negative LVNC patients.

Image Improved Intravoxel Incoherent Motion MRI With Optimized Trigger Delays Based on Strain Curve Analysis to Evaluate Myocardial Microvascular Dysfunction of Exertional Heat Illness

BACKGROUND

Intravoxel incoherent motion (IVIM) MRI has not been widely used and its role in evaluating exertional heat illness (EHI)-related myocardial involvement remains unknown.

PURPOSE

To investigate the feasibility of strain curve-derived trigger delay (TD) IVIM-MRI and its role in assessing myocardial diffusion and microvascular perfusion of EHI patients.

STUDY TYPE

Prospective.

SUBJECTS

A total of 42 male EHI patients (median age: 21 years) and 22 age- and sex-matched healthy controls (HC).

FIELD STRENGTH/SEQUENCE

A 3-T, diffusion-weighted spin-echo echo-planar-imaging sequence.

ASSESSMENT

IVIM-MRI was acquired by conventional TD method (group A) or strain curve-based TD method (group B) in random order. IVIM image quality was evaluated on a 3-point Likert scale (1, nondiagnostic; 2, moderate; 3, good). Technical success was defined as image quality score = 3. IVIM-MRI-derived parameters (pseudo diffusion in the capillaries [D*], perfusion fraction [f], and slow apparent diffusion coefficient [D]) were compared between EHI and HC.

STATISTICAL TESTS

Student's t-tests, chi-square tests, one-way analysis of variance, receiver operating characteristic (ROC) curve analysis, Pearson's correlation coefficient (r). The statistical significance level was set at P < 0.05.

RESULTS

IVIM-MRI image quality score (median [interquartile range]: 3 [2, 3] vs. 2 [1-3]) and technical success rate (61.9%[13/21] vs. 28.6%[6/21]) were significantly improved in group B. EHI patients showed significantly decreased D* (118.1 ± 23.3 × 10-3  mm2 /sec vs. 142.7 ± 42.6 × 10-3  mm2 /sec) and f values (0.42 ± 0.12 vs. 0.51 ± 0.11) and significantly higher D values (3.0 ± 0.9 × 10-3  mm2 /sec vs. 2.5 ± 0.6 × 10-3  mm2 /sec) compared to HC. Relative to D and D*, f showed the most robust efficacy for detecting EHI-related myocardial injury with the highest area under the ROC curve (0.906: 95% confidence interval, 0.799, 0.967) and sensitivity of 88.5% and specificity of 85.6%.

CONCLUSION

The strain curve-based TD method significantly improved image quality and technical success rate of IVIM-MRI, and f value may be an effective biomarker to assess myocardial microcirculation abnormalities of EHI patients.

EVIDENCE LEVEL

2.

TECHNICAL EFFICACY

Stage 3.

Ventricular-atrial coupling in subjects with normal, preserved, and reduced left ventricular ejection fraction: insights from cardiac magnetic resonance imaging

OBJECTIVES

To assess the correlation between LA and LV strain measurements in different clinical scenarios and evaluate to what extent LA deformation contributes to the prognosis of patients.

METHODS

A total of 297 consecutive participants including 75 healthy individuals, 75 hypertrophic cardiomyopathy (HCM) patients, 74 idiopathic dilated cardiomyopathy (DCM), and 73 chronic myocardial infarction (MI) patients were retrospectively enrolled in this study. The associations of LA-LV coupling with clinical status were statistically analyzed by correlation, multiple linear regression, and logistic regression. Survival estimates were calculated by receiver operating characteristic analyses and Cox regression analyses.

RESULTS

Overall, moderate correlations were found between LA and LV strain in every phase of the cardiac cycle (r: -0.598 to -0.580, all p < 0.001). The slope of the regression line of the individual strain-strain curve had a significant difference among 4 groups (-1.4 ± 0.3 in controls, -1.1 ± 0.6 in HCM, -1.8 ± 0.8 in idiopathic DCM, -2.4 ± 1.1 in chronic MI, all p < 0.05). During a median follow-up of 4.7 years, the total LA emptying fraction was independently associated with primary (hazard ratio: 0.968, 95% CI: 0.951-0.985) and secondary endpoints (hazard ratio: 0.957, 95% CI: 0.930-0.985) with an area under the curve (AUC) of 0.720 respectively, 0.806, which was significantly higher than the AUC of LV parameters.

CONCLUSIONS

The coupled correlations between the left atria and ventricle in every phase and the individual strain-strain curve vary with etiology. LA deformation in late diastole provides prior and incremental information on cardiac dysfunction based on LV metrics. The total LA emptying fraction was an independent indicator for clinical outcome superior to that of LV typical predictors.

CLINICAL RELEVANCE STATEMENT

Left ventricular-atrial coupling is not only valuable for comprehending the pathophysiological mechanisms of cardiovascular diseases caused by different etiologies but also holds significant importance for the prevention of adverse cardiovascular events and targeted treatment.

KEY POINTS

• In HCM patients with preserved LVEF, LA deformation is a sensitive indicator for cardiac dysfunction prior to LV parameters with a reduced LA/LV strain ratio. • In patients with reduced LVEF, LV deformation impairment is more consequential than that of the LA with an increased LA/LV strain ratio. Furthermore, impaired LA active strain indicates potential atrial myopathy. • Among LA and LV parameters, the total LA emptying fraction is the best predictor for guiding clinical management and follow-up in patients with different statuses of LVEF.

Cardiac magnetic resonance imaging T1 mapping and late gadolinium enhancement entropy: Prognostic value in patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) affects the myocardium, thereby resulting in a poor prognosis. Late gadolinium enhancement (LGE) entropy, derived from routine cardiac magnetic resonance (CMR) LGE images, is an index that reflects the complexity of the left ventricular myocardium. The aim of this study was to investigate whether LGE entropy can serve as a prognostic factor in patients with SSc.

METHODS

Twenty-four patients with SSc, who underwent CMR-T1 mapping and LGE to identify myocardial damage, were enrolled, and LGE entropy was measured. Extracellular volume (ECV) values were calculated using the same CMR-LGE images. The endpoint was major adverse cardiac events (MACEs), comprising all-cause death, hospitalization due to heart failure, and the onset of sustained ventricular tachycardia and ventricular fibrillation. The ability to predict MACE was assessed using receiver operating characteristic (ROC) analysis, and the predictability of LGE entropy was analyzed using Kaplan-Meier analysis.

RESULTS

The ROC curve analysis demonstrated a cut-off value of 7.39 for MACE with LGE entropy and had a sensitivity and specificity of 80 % and 79 %, respectively. Patients with LGE entropy ≥7.39 had a significantly higher MACE rate than those with LGE entropy <7.39 (p = 0.010). Moreover, LGE entropy ≥7.39 was a poor prognostic factor in patients without elevated ECV values.

CONCLUSIONS

LGE entropy can be used to predict MACE and allows for further risk stratification in addition to ECV determination.

Electrocardiographic characteristics associated with late gadolinium enhancement and prognostic value in patients with dilated cardiomyopathy

Background

Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging has emerged as an important tool for assessment of patients with dilated cardiomyopathy (DCM). Electrocardiography (ECG) is an accessible, reproducible, low-cost diagnostic and prognostic tool. This study aimed to investigate the ECG characteristics associated with LGE, as well as to assess the prognostic significance of ECG in patients with DCM.

Methods

Consecutive patients diagnosed with DCM by CMR [left ventricular ejection fraction (LVEF) < 50%] between 2011 and 2020 were included. Multivariable analysis was conducted to evaluate ECG predictors associated with LGE. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of ECG in combination of clinical data and LVEF for LGE. Two composite outcomes were also assessed among patients with and without ECG predictors: (1) sudden cardiac death (SCD), sustained ventricular arrhythmia, or appropriate implantable cardioverter-defibrillator (ICD) therapy, and (2) all-cause death or hospitalization for heart failure.

Results

A total of 422 patients, with a mean age of 59.5 ± 16.3 years (58.3% male), were included. LGE was present in 169 (40%) of the patients. Multivariable analysis identified lateral inverted T-waves, intraventricular conduction delay, low voltage, and fragmented QRS as independent predictors of LGE. ROC analysis showed a significant increase in the area under the curve (AUC) when ECG predictors of the four aforementioned characteristics were added to the clinical-LVEF model (AUC 0.66, 95% CI 0.59-0.71 vs. 0.72, 95% CI 0.67-0.78, p = 0.003). During a median follow-up of 2.7 years (IQR 0.8, 5.2), 16 events of SCD, sustained ventricular arrhythmia, or appropriate ICD therapy, and 70 events of all-cause death or hospitalization for heart failure occurred. ECG predictors were independently associated with SCD, sustained ventricular arrhythmia, or appropriate ICD therapy (HR 4.84, 95% CI 1.34-17.40, p = 0.01). However, ECG predictors were not associated with all-cause death or hospitalization for heart failure (HR 1.22, 95% CI 0.76-1.96, p = 0.39).

Conclusion

In patients with DCM, lateral inverted T-waves, intraventricular conduction delay, low voltage, and fragmented QRS were independently associated with LGE. Additionally, these ECG predictors had prognostic value for predicting SCD, sustained ventricular arrhythmia, or appropriate ICD therapy, assisting clinicians in stratifying SCD risk and identifying primary prevention ICD implantation candidates.

Impact of Cardiac Magnetic Resonance to Arrhythmic Risk Stratification in Nonischemic Cardiomyopathy

Left ventricular ejection fraction-based arrhythmic risk stratification in nonischemic cardiomyopathy (NICM) is insufficient and has led to the failure of primary prevention implantable cardioverter defibrillator trials, mainly due to the inability of selecting patients at high risk for sudden cardiac death (SCD). Cardiac magnetic resonance offers unique opportunities for tissue characterization and has gained a central role in arrhythmic risk stratification in NICM. The presence of myocardial scar, denoted by late gadolinium enhancement, is a significant, independent, and strong predictor of ventricular arrhythmias and SCD with high negative predictive value. T1 maps and extracellular volume fraction, which are able to quantify diffuse fibrosis, hold promise as complementary tools but need confirmatory results from large studies.

Quantification of myocardial extracellular volume without blood sampling

Aims

Cardiac magnetic resonance (CMR) T1 relaxation time mapping is an established technique primarily used to identify diffuse interstitial fibrosis and oedema. The myocardial extracellular volume (ECV) can be calculated from pre- and post-contrast T1 relaxation times and is a reproducible parametric index of the proportion of volume occupied by non-cardiomyocyte components in myocardial tissue. The conventional calculation of the ECV requires blood sampling to measure the haematocrit (HCT). Given the high variability of the HCT, the blood collection is recommended within 24 h of the CMR scan, limiting its applicability and posing a barrier to the clinical routine use of ECV measurements. In recent years, several research groups have proposed a method to determine the ECV by CMR without blood sampling. This is based on the inverse relationship between the T1 relaxation rate (R1) of blood and the HCT. Consequently, a 'synthetic' HCT could be estimated from the native blood R1, avoiding blood sampling.

Methods and results

We performed a review and meta-analysis of published studies on synthetic ECV, as well as a secondary analysis of previously published data to examine the effect of the chosen regression modell on bias. While, overall, a good correlation and little bias between synthetic and conventional ECV were found in these studies, questions regarding its accuracy remain.

Conclusion

Synthetic HCT and ECV can provide a 'non-invasive' quantitative measurement of the myocardium's extracellular space when timely HCT measurements are not available and large alterations in ECV are expected, such as in cardiac amyloidosis. Due to the dependency of T1 relaxation times on the local setup, calculation of local formulas using linear regression is recommended, which can be easily performed using available data.

Impact of late gadolinium-enhanced cardiac MRI on arrhythmic and mortality outcomes in nonischemic dilated cardiomyopathy: updated systematic review and meta-analysis

Risk stratification based mainly on the impairment of left ventricular ejection fraction has limited performance in patients with nonischemic dilated cardiomyopathy (NIDCM). Evidence is rapidly growing for the impact of myocardial scar identified by late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMR) on cardiovascular events. We aim to assess the prognostic value of LGE on long-term arrhythmic and mortality outcomes in patients with NIDCM. PubMed, Scopus, and Cochrane databases were searched from inception to January 21, 2022. Studies that included disease-specific subpopulations of NIDCM were excluded. Data were independently extracted and combined via random-effects meta-analysis using a generic inverse-variance strategy. Data from 60 studies comprising 15,217 patients were analyzed with a 3-year median follow-up. The presence of LGE was associated with major ventricular arrhythmic events (pooled OR: 3.99; 95% CI 3.08, 5.16), all-cause mortality (pooled OR: 2.14; 95% CI 1.81, 2.52), cardiovascular mortality (pooled OR 2.83; 95% CI 2.23, 3.60), and heart failure hospitalization (pooled OR: 2.53; 95% CI 1.78, 3.59). Real-world evidence suggests that the presence of LGE on CMR was a strong predictor of adverse long-term outcomes in patients with NIDCM. Scar assessment should be incorporated as a primary determinant in the patient selection criteria for primary prophylactic implantable cardioverter-defibrillator placement.

Native T1 mapping in early diffuse and limited systemic sclerosis, and its association with diastolic function

BACKGROUND

Systemic sclerosis (SSc) is divided into diffuse and limited cutaneous SSc (dcSSc and lcSSc). The dcSSc subtype has more severe internal organ damage. This study aimed to assess whether cardiovascular magnetic resonance (CMR) parametric mapping could detect early cardiac involvement and evaluate differences between these two subtypes.

METHODS

Eighty SSc patients (37 dcSSc and 43 lcSSc) underwent CMR at 3.0 T (Philips Healthcare, Best, The Netherlands) in our hospital between July 2018 and July 2021. We analyzed myocardial damage by CMR parametric mapping and compared it with clinical data.

RESULTS

The median duration of the disease was 10.2 months. The left ventricular ejection fraction was preserved in both groups. DcSSc had significantly higher native T1 (1333.4 ± 71.2 ms vs. 1295.0 ± 42.7 ms, p = 0.006) and extracellular volume fraction (32.6 ± 4.1 % vs. 30.3 ± 4.0 %, p = 0.018) in the mid-ventricular septum as compared to lcSSc, although there were no differences in T2 values. Native T1 values were positively correlated with the E/e' ratio and left atrial volume indices evaluated by transthoracic echocardiography in overall SSc and dcSSc, but not in lcSSc. Logistic regression analysis revealed that native T1 was an independent predictor of left ventricular diastolic dysfunction in SSc patients (odds ratio, 1.194; 95 % confidence interval, 1.021-1.396; p = 0.026). Native T1 was higher in SSc patients with progressive skin lesions. Additionally, there were positive correlations between brain natriuretic peptide, New York Heart Association functional classification, and native T1.

CONCLUSIONS

CMR parametric mapping is a useful tool for detecting myocardial changes. Native T1 was the most sensitive parameter for identifying diffuse myocardial changes in the early stages of SSc and was associated with left ventricular diastolic function. DcSSc had more severe myocardial involvement than lcSSc; therefore, the use of CMR parametric mapping may aid in its prediction.

Multicenter research priorities in pediatric CMR: results of a collaborative wiki survey

Multicenter studies in pediatric cardiovascular magnetic resonance (CMR) improve statistical power and generalizability. However, a structured process for identifying important research topics has not been developed. We aimed to (1) develop a list of high priority knowledge gaps, and (2) pilot the use of a wiki survey to collect a large group of responses. Knowledge gaps were defined as areas that have been either unexplored or under-explored in the research literature. High priority goals were: (1) feasible and answerable from a multicenter research study, and (2) had potential for high impact on the field of pediatric CMR. Seed ideas were contributed by a working group and imported into a pairwise wiki survey format which allows for new ideas to be uploaded and voted upon ( https://allourideas.org ). Knowledge gaps were classified into 2 categories: 'Clinical CMR Practice' (16 ideas) and 'Disease Specific Research' (22 ideas). Over a 2-month period, 3,658 votes were cast by 96 users, and 2 new ideas were introduced. The 3 highest scoring sub-topics were myocardial disorders (9 ideas), translating new technology & techniques into clinical practice (7 ideas), and normal reference values (5 ideas). The highest priority gaps reflected strengths of CMR (e.g., myocardial tissue characterization; implementation of technologic advances into clinical practice), and deficiencies in pediatrics (e.g., data on normal reference values). The wiki survey format was effective and easy to implement, and could be used for future surveys.

Detection of Early Diffuse Myocardial Fibrosis and Inflammation in Chagas Cardiomyopathy with T1 Mapping and Extracellular Volume

Purpose

To evaluate myocardial T1 mapping and extracellular volume (ECV) parameters in different stages of Chagas cardiomyopathy and determine whether they are predictive of disease severity and prognosis.

Materials and Methods

Prospectively enrolled participants (July 2013 to September 2016) underwent cine and late gadolinium enhancement (LGE) cardiac MRI and T1 mapping with a precontrast (native) or postcontrast modified Look-Locker sequence. The native T1 and ECV values were measured among subgroups that were based on disease severity (indeterminate, Chagas cardiomyopathy with preserved ejection fraction [CCpEF], Chagas cardiomyopathy with midrange ejection fraction [CCmrEF], and Chagas cardiomyopathy with reduced ejection fraction [CCrEF]). Cox proportional hazards regression and the Akaike information criterion were used to determine predictors of major cardiovascular events (cardioverter defibrillator implant, heart transplant, or death).

Results

In 107 participants (90 participants with Chagas disease [mean age ± SD, 55 years ± 11; 49 men] and 17 age- and sex-matched control participants), the left ventricular (LV) ejection fraction and the extent of focal and diffuse or interstitial fibrosis were correlated with disease severity. Participants with CCmrEF and participants with CCrEF showed significantly higher global native T1 and ECV values than participants in the indeterminate, CCpEF, and control groups (T1: 1072 msec ± 34 and 1073 msec ± 63 vs 1010 msec ± 41, 1005 msec ± 69, and 999 msec ± 46; ECV: 35.5% ± 3.6 and 35.0% ± 5.4 vs 25.3% ± 3.5, 28.2% ± 4.9, and 25.2% ± 2.2; both P < .001). Remote (LGE-negative areas) native T1 and ECV values were also higher (T1: 1056 msec ± 32 and 1071 msec ± 55 vs 1008 msec ± 41, 989 msec ± 96, and 999 msec ± 46; ECV: 30.2% ± 4.7 and 30.8% ± 7.4 vs 25.1% ± 3.5, 25.1% ± 3.7, and 25.0% ± 2.2; both P < .001). Abnormal remote ECV values (>30%) occurred in 12% of participants in the indeterminate group, which increased with disease severity. Nineteen combined outcomes were observed (median follow-up time: 43 months), and a remote native T1 value greater than 1100 msec was independently predictive of combined outcomes (hazard ratio, 12 [95% CI: 4.1, 34.2]; P < .001).

Conclusion

Myocardial native T1 and ECV values were correlated with Chagas disease severity and may serve as markers of myocardial involvement in Chagas cardiomyopathy that precede LGE and LV dysfunction.Keywords: MRI, Cardiac, Heart, Imaging Sequences, Chagas Cardiomyopathy Supplemental material is available for this article. © RSNA, 2023.

T1 Map-Based Radiomics for Prediction of Left Ventricular Reverse Remodeling in Patients With Nonischemic Dilated Cardiomyopathy

OBJECTIVE

This study aimed to develop and validate models using radiomics features on a native T1 map from cardiac magnetic resonance (CMR) to predict left ventricular reverse remodeling (LVRR) in patients with nonischemic dilated cardiomyopathy (NIDCM).

MATERIALS AND METHODS

Data from 274 patients with NIDCM who underwent CMR imaging with T1 mapping at Severance Hospital between April 2012 and December 2018 were retrospectively reviewed. Radiomic features were extracted from the native T1 maps. LVRR was determined using echocardiography performed ≥ 180 days after the CMR. The radiomics score was generated using the least absolute shrinkage and selection operator logistic regression models. Clinical, clinical + late gadolinium enhancement (LGE), clinical + radiomics, and clinical + LGE + radiomics models were built using a logistic regression method to predict LVRR. For internal validation of the result, bootstrap validation with 1000 resampling iterations was performed, and the optimism-corrected area under the receiver operating characteristic curve (AUC) with 95% confidence interval (CI) was computed. Model performance was compared using AUC with the DeLong test and bootstrap.

RESULTS

Among 274 patients, 123 (44.9%) were classified as LVRR-positive and 151 (55.1%) as LVRR-negative. The optimism-corrected AUC of the radiomics model in internal validation with bootstrapping was 0.753 (95% CI, 0.698-0.813). The clinical + radiomics model revealed a higher optimism-corrected AUC than that of the clinical + LGE model (0.794 vs. 0.716; difference, 0.078 [99% CI, 0.003-0.151]). The clinical + LGE + radiomics model significantly improved the prediction of LVRR compared with the clinical + LGE model (optimism-corrected AUC of 0.811 vs. 0.716; difference, 0.095 [99% CI, 0.022-0.139]).

CONCLUSION

The radiomic characteristics extracted from a non-enhanced T1 map may improve the prediction of LVRR and offer added value over traditional LGE in patients with NIDCM. Additional external validation research is required.

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.

Cardiovascular Magnetic Resonance Imaging Findings in Africans with Idiopathic Dilated Cardiomyopathy

In sub-Saharan Africa, idiopathic dilated cardiomyopathy (IDCM) is a common yet poorly investigated cause of heart failure. Cardiovascular magnetic resonance (CMR) imaging is the gold standard for tissue characterisation and volumetric quantification. In this paper, we present CMR findings obtained from a cohort of patients with IDCM in Southern Africa suspected of having a genetic cause of cardiomyopathy. A total of 78 IDCM study participants were referred for CMR imaging. The participants had a median left ventricular ejection fraction of 24% [interquartile range, (IQR): 18-34]. Late gadolinium enhancement (LGE) was visualised in 43 (55.1%) participants and localised in the midwall in 28 (65.0%) participants. At the time of enrolment into the study, non-survivors had a higher median left ventricular end diastolic wall mass index of 89.4 g/m² (IQR: 74.5-100.6) vs. 73.6 g/m² (IQR: 51.9-84.7), p = 0.025 and a higher median right ventricular end-systolic volume index of 86 mL/m² (IQR:74-105) vs. 41 mL/m² (IQR: 30-71), p < 0.001. After one year, 14 participants (17.9%) died. The hazard ratio for the risk of death in patients with evidence of LGE from CMR imaging was 0.435 (95% CI: 0.259-0.731; p = 0.002). Midwall enhancement was the most common pattern, visualised in 65% of participants. Prospective, adequately powered, and multi-centre studies across sub-Saharan Africa are required to determine the prognostic significance of CMR imaging parameters such as late gadolinium enhancement, extracellular volume fraction, and strain patterns in an African IDCM cohort.

Prognostic value of cardiovascular magnetic resonance T1 mapping and extracellular volume fraction in nonischemic dilated cardiomyopathy

BACKGROUND

Heart failure- (HF) and arrhythmia-related complications are the main causes of morbidity and mortality in patients with nonischemic dilated cardiomyopathy (NIDCM). Cardiovascular magnetic resonance (CMR) imaging is a noninvasive tool for risk stratification based on fibrosis assessment. Diffuse interstitial fibrosis in NIDCM may be a limitation for fibrosis assessment through late gadolinium enhancement (LGE), which might be overcome through quantitative T1 and extracellular volume (ECV) assessment. T1 and ECV prognostic value for arrhythmia-related events remain poorly investigated. We asked whether T1 and ECV have a prognostic value in NIDCM patients.

METHODS

This prospective multicenter study analyzed 225 patients with NIDCM confirmed by CMR who were followed up for 2 years. CMR evaluation included LGE, native T1 mapping and ECV values. The primary endpoint was the occurrence of a major adverse cardiovascular event (MACE) which was divided in two groups: HF-related events and arrhythmia-related events. Optimal cutoffs for prediction of MACE occurrence were calculated for all CMR quantitative values.

RESULTS

Fifty-eight patients (26%) developed a MACE during follow-up, 42 patients (19%) with HF-related events and 16 patients (7%) arrhythmia-related events. T1 Z-score (p = 0.008) and global ECV (p = 0.001) were associated with HF-related events occurrence, in addition to left ventricular ejection fraction (p < 0.001). ECV > 32.1% (optimal cutoff) remained the only CMR independent predictor of HF-related events occurrence (HR 2.15 [1.14-4.07], p = 0.018). In the arrhythmia-related events group, patients had increased native T1 Z-score and ECV values, with both T1 Z-score > 4.2 and ECV > 30.5% (optimal cutoffs) being independent predictors of arrhythmia-related events occurrence (respectively, HR 2.86 [1.06-7.68], p = 0.037 and HR 2.72 [1.01-7.36], p = 0.049).

CONCLUSIONS

ECV was the sole independent predictive factor for both HF- and arrhythmia-related events in NIDCM patients. Native T1 was also an independent predictor in arrhythmia-related events occurrence. The addition of ECV and more importantly native T1 in the decision-making algorithm may improve arrhythmia risk stratification in NIDCM patients. Trial registration NCT02352129. Registered 2nd February 2015-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02352129.

Cardiovascular magnetic resonance for the evaluation of patients with cardiovascular disease: An overview of current indications, limitations, and procedures

Cardiovascular disease (CVD) is the most common cause of morbidity/mortality worldwide. Early diagnosis is the key to improve CVD prognosis, and cardiovascular imaging plays a crucial role in this direction. Echocardiography is the most commonly used imaging modality. However, the need for early diagnosis/treatment favors the development of modalities providing information about tissue characterization beyond echocardiography. In this context, the rapid evolution of cardiovascular magnetic resonance (CMR) led to the coexistence of cardiologists and radiologists in the CMR field. Our aim was to provide an overview of indications, sequences, and reporting of CMR findings in various CVDs. The indications/limitations of CMR as well as the pathophysiological significance of various sequences in adult/pediatric CVDs are presented and discussed in detail. The role of CMR indices in the evaluation of the most common clinical scenarios in cardiology and their impact on CVD diagnosis/prognosis were analyzed in detail. Additionally, the comparison of CMR versus other imaging modalities is also discussed. Finally, future research directions are presented. CMR can provide cardiac tissue characterization and biventricular/biatrial functional assessment in the same examination, allowing for early and accurate identification of important subclinical abnormalities, before clinically overt CVD takes place.

Prognostic Value of Hepatic Native T1 and Extracellular Volume Fraction in Patients with Pulmonary Arterial Hypertension

Background

Right heart failure may lead to impaired liver perfusion and venous congestion, resulting in different extents of liver fibrosis. However, whether hepatic tissue deterioration determined by native T1 mapping and extracellular volume fraction using cardiac magnetic resonance imaging is associated with poor outcomes in patients with pulmonary arterial hypertension remains unclear.

Methods and Results

A total of 131 participants with pulmonary arterial hypertension (mean age, 36±13 years) and 64 healthy controls (mean age, 44±18) between October 2013 and December 2019 were prospectively enrolled. Hepatic native T1 and extracellular volume fraction values were measured using modified Look–Locker inversion recovery T1 mapping sequences. The primary end point was all‐cause mortality; the secondary end point was all‐cause mortality and repeat hospitalization attributable to heart failure. Cox regression models and Kaplan–Meier survival analysis were used to identify the association between variables and clinical outcome. During a median follow‐up of 34.5 months (interquartile range: 25.3–50.8), hepatic native T1 (hazard ratio per 30‐ms increase, 1.22 [95% CI, 1.07–1.39]; P =0.003) and extracellular volume fraction (hazard ratio per 3% increase, 1.18 [95% CI, 1.04–1.34]; P =0.010) values were associated with a higher risk of death. In the multivariate Cox model, hepatic native T1 value (hazard ratio per 30‐ms increase, 1.15 [95% CI, 1.04–1.27]; P =0.009) remained as an independent prognostic factor for the secondary end point.

Conclusions

Hepatic T1 mapping values were predictors of adverse cardiovascular events in participants with pulmonary arterial hypertension and could be novel imaging biomarkers for poor prognosis recognition.

Cardiovascular Imaging in China: Yesterday, Today, and Tomorrow

The high prevalence and mortality of cardiovascular diseases in China's large population has increased the use of cardiovascular imaging for the assessment of conditions in recent years. In this study, we review the past 20 years of cardiovascular imaging in China, the increasingly important role played by cardiovascular computed tomography in coronary artery disease and pulmonary embolism assessment, magnetic resonance imaging's use for cardiomyopathy assessment, the development and application of artificial intelligence in cardiovascular imaging, and the future of Chinese cardiovascular imaging.

Detection of myocardial fibrosis: Where we stand

Myocardial fibrosis, resulting from the disturbance of extracellular matrix homeostasis in response to different insults, is a common and important pathological remodeling process that is associated with adverse clinical outcomes, including arrhythmia, heart failure, or even sudden cardiac death. Over the past decades, multiple non-invasive detection methods have been developed. Laboratory biomarkers can aid in both detection and risk stratification by reflecting cellular and even molecular changes in fibrotic processes, yet more evidence that validates their detection accuracy is still warranted. Different non-invasive imaging techniques have been demonstrated to not only detect myocardial fibrosis but also provide information on prognosis and management. Cardiovascular magnetic resonance (CMR) is considered as the gold standard imaging technique to non-invasively identify and quantify myocardial fibrosis with its natural ability for tissue characterization. This review summarizes the current understanding of the non-invasive detection methods of myocardial fibrosis, with the focus on different techniques and clinical applications of CMR.

The prognostic value of right ventricular ejection fraction by cardiovascular magnetic resonance in heart failure: A systematic review and meta-analysis

BACKGROUND

Cardiac magnetic resonance (CMR) is considered the gold standard for the assessment of right ventricular ejection fraction (RVEF). Previous studies have suggested that RVEF may be a predictor of adverse outcomes in heart failure (HF). In this study, we aimed to systematically review the prognostic value of RVEF, evaluated by CMR, across the spectrum of left ventricular systolic function in patients with HF.

METHODS

Electronic databases were searched for studies investigating the prognostic value of RVEF in HF, irrespective of left ventricular ejection fraction (LVEF). A random-effects meta-analysis was conducted for mortality and HF hospitalization. Subgroup analyses were also performed based on the presence of reduced (<50%) or preserved LVEF (≥50%).

RESULTS

In total, 46 studies enrolling 14,344 patients were included. In the pooled analyses, impaired RVEF was a powerful predictor of mortality (HR: 1.26, 95% CI: 1.18-1.33, I²: 13%, per 10% decrease in RVEF) and death or HF hospitalization (HR: 1.31, 95% Cl: 1.2-1.42, I²: 27%, per 10% decrease in RVEF). A decrease in RVEF was strongly associated with increased risk of mortality or hospitalization both in HF with reduced EF (HR: 1.24, 95% CI: 1.13-1.36, I²: 2%, per 10% decrease in RVEF) and in HF with preserved EF (HR: 1.24, 95% CI: 1.09-1.40, I²: 0%, per 10% decrease in RVEF).

CONCLUSION

Impaired RVEF on CMR strongly predicts adverse outcomes in patients with HF regardless of LVEF. RV systolic function should be carefully evaluated in these patients. Prospero Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021256967.

Native Myocardial T1 Value in Predicting 1-Year Outcomes in Patients with Nonischemic Dilated Cardiomyopathy Experiencing Recent Heart Failure

The evidence for the clinical implications, especially the short-term utility, of native myocardial T1 value (T1_native) on cardiac magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (NIDCM) is scant. We investigated the potential of T1_native to assess left ventricular (LV) myocardial characteristics and predict 1-year outcomes in patient with NIDCM experiencing recent heart failure (HF).Forty-five patients with NIDCM and HF symptoms within 3 months underwent CMR with cine, non-contrast T1 mapping, and late gadolinium enhancement (LGE). T1_native per patient was defined as an averaged T1 value of 5 short-axis slices of base-to-apex LV myocardium. The appearance of LGE was visually examined. T1_native correlated with the LV end-diastolic dimension normalized to height (LVEDD) (r = 0.38, P = 0.0103), ejection fraction (r = -0.39, P = 0.009), and serum N-terminal pro-brain natriuretic peptide levels (r = 0.48, P = 0.001), whereas the presence and segmental extent of LGE correlated only with LVEDD. In the 1-year follow-up cohort, the optimal cutoffs of T1_native for predicting LV reverse remodeling (LVRR) and combined cardiac events (cardiac death, ventricular tachycardia/fibrillation, heart failure hospitalization) were 1366 ms and 1377 ms, respectively. In multivariate analysis, T1_native < 1366 ms and T1_native > 1377 ms remained significant predictors of LVRR (odds ratio, 11.3) and cardiac events (hazard ratio, 15.3), respectively, whereas the presence and segmental extent of LGE did not.T1_native in patients with NIDCM experiencing recent HF may offer a promising strategy for assessing LV myocardial characteristics and predicting 1-year LVRR and cardiac events.

Myocardial Extracellular Volume Fraction Measured by Cardiac Magnetic Resonance Imaging Negatively Correlates With Cardiomyocyte Breadth in a Healthy Porcine Model

Background

The extracellular volume fraction (ECV) derived from cardiac magnetic resonance imaging (MRI) is extensively used to evaluate myocardial fibrosis. However, due to the limited histological verification in healthy individuals, it remains unclear whether the size of cardiomyocytes may play a potential role in the physiological changes of ECV. The aim of this study was to examine the association between cardiomyocyte size and myocardial ECV by using a healthy porcine model.

Methods

Sixteen domestic healthy pigs were anesthetized and underwent cardiac MRI with mechanical controlled breathing. Intravenous contrast medium was introduced at a dose of 0.2–0.25 mmol/kg. The interventricular septum ECV was calculated using an established MRI procedure, which was based on the pre- and post-contrast T1 values of the heart and individual blood hematocrit. The cardiomyocyte breadth (CmyB) in cross section was measured by hematoxylin and eosin staining to reflect the cardiomyocyte size.

Results

Data were successfully acquired from 14 pigs. The CmyB was obtained from the myocardial tissues corresponding to the region of interest on cardiac MRI. The mean ± SD of the ECV was 0.253 ± 0.043, and the mean ± SD of the CmyB was 10.02 ± 0.84 μm. The ECV exhibited a negative correlation with the CmyB (r = −0.729, p = 0.003).

Conclusion

The myocardial ECV detected by cardiac MRI is negatively correlated with the CmyB in healthy pigs, demonstrating that the size of cardiomyocytes is potentially associated with the ECV under physiological conditions.

Preliminary study on the diagnostic value of cardiac magnetic resonance feature tracking for malignant ventricular arrhythmias in non-ischemic dilated cardiomyopathy

Background

Patients with nonischemic dilated cardiomyopathy (NIDCM) and malignant ventricular arrhythmia (MVA) often have a poor prognosis and a high risk of sudden cardiac death. Although the diagnosis of MVA is straightforward by electrocardiogram (ECG), the underlying abnormalities of ventricular mechanics in these patients are unknown. This study aims to preliminarily explore the value of cardiac magnetic resonance feature tracking (CMR-FT) for MVA in dilated cardiomyopathy.

Methods

In this retrospective study, patients with NIDCM who met inclusion criteria were divided into an MVA group and a non-MVA group (included from January 2018 to September 2021). The interobserver agreement of myocardial strain parameters, including global longitudinal strain (GLS), global circumferential strain (GCS) and global radial strain (GRS), were tested. The GLS, GCS, GRS, left ventricular ejection fraction (LVEF), T_peak-T_end interval on ECG and brain natriuretic peptide (BNP) were compared between groups. Single-factor and multifactor receiver operating characteristic (ROC) curve analyses were conducted to calculate the area under the ROC curve (AUC), cut-off point, sensitivity, and specificity of these parameters in predicting MVA in NIDCM.

Results

A total of 161 NIDCM patients were included (54 in the MVA group). GLS, GCS, and GRS had good interobserver agreement (all intraclass correlation coefficients >0.80). The absolute GLS and GCS, GRS and LVEF were lower in the MVA group than the non-MVA group (P<0.001), T_peak-T_end and BNP were higher (P<0.001). Single-factor ROC curve analysis showed that GLS, GCS and GRS had certain diagnostic value for MVA (AUC =0.795, 0.802, and 0.754, respectively). Among them, GCS had higher sensitivity and specificity (GCS 0.796/0.776, GLS 0.778/0.757, GRS 0.741/0.692). Multifactor ROC curve analysis showed the combination of GLS and GCS (AUC =0.810), the combination of GCS and GRS (AUC =0.802), the combination of GLS and GRS (AUC =0.787), the combination of GLS, GCS, and GRS (AUC =0.810).

Conclusions

The three-dimensional myocardial strain parameters (especially GLS and GCS) measured by CMR-FT had certain diagnostic value and could reflect the underlying abnormality of ventricular mechanics of NIDCM with MVA.

Myocardial mechanics in dilated cardiomyopathy: prognostic value of left ventricular torsion and strain

BACKGROUND

Data on the prognostic value of left ventricular (LV) morphological and functional parameters including LV rotation in patients with dilated cardiomyopathy (DCM) using cardiovascular magnetic resonance (CMR) are currently scarce. In this study, we assessed the prognostic value of global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) and LV torsion using CMR feature tracking (FT).

METHODS

CMR was performed in 350 DCM patients and 70 healthy subjects across 5 different European CMR Centers. Myocardial strain parameters were retrospectively assessed from conventional balanced steady-state free precession cine images applying FT. A combined primary endpoint (cardiac death, heart transplantation, aborted sudden cardiac death) was defined for the assessment of clinical outcome.

RESULTS

GLS, GCS, GRS and LV torsion were significantly lower in DCM patients than in healthy subjects (all p < 0.001). The primary endpoint occurred in 59 (18.7%) patients [median follow-up 4.2 (2.0-5.6) years]. In the univariate analyses all strain parameters showed a significant prognostic value (p < 0.05). In the multivariate model, LV strain parameters, particularly GLS provided an incremental prognostic value compared to established CMR parameters like LV ejection fraction and late gadolinium enhancement. A scoring model including six categorical variables of standard CMR and strain parameters differentiated further risk subgroups.

CONCLUSION

LV strain assessed with CMR FT has a high prognostic value in patients with DCM, surpassing routine and dedicated functional parameters. Thus, CMR strain imaging may contribute to the improvement of risk stratification in DCM.