Tissue Characterization by Mapping and Strain Cardiac MRI to Evaluate Myocardial Inflammation in Fulminant Myocarditis

The Impact of Long COVID-19 on the Cardiovascular System

Long coronavirus disease (COVID) is the development or persistence of symptoms after an acute SARS-CoV-2 (COVID-19) infection. Fewer patients are developing acute COVID-19 infections, but patients with long COVID continue to have alarming long-term sequelae. Many cardiac magnetic resonance imaging studies show significant changes in cardiac structure after a COVID-19 infection, suggestive of an increased burden of many cardiovascular diseases, notably myocarditis. The pathophysiology of COVID-19 requires viral binding to angiotensin-converting enzyme 2 protein receptors throughout the body, which are upregulated by inflammation. Consequently, the numerous preexisting conditions that worsen or prolong inflammation enhance this binding and have differing effects on patients based on their unique immune systems. These pathophysiological changes drive long COVID cardiac sequelae such as inappropriate sinus tachycardia, postural orthostatic tachycardia, and other types of orthostatic intolerance. Increased screening for long COVID and low-risk interventions such as exercise regimens could alleviate the suffering endured by patients with long COVID. Many studies such as the Researching COVID to Enhance Recovery Initiative (RECOVER) trials at the National Institutes of Health are exploring potential treatments for long COVID patients.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

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.

COVID-19 and Acute Cardiac Injury: Clinical Manifestations, Biomarkers, Mechanisms, Diagnosis, and Treatment

PURPOSE OF REVIEW

This review aims to comprehensively explore the clinical characteristics of COVID-19-related cardiac injury and examine the potential mechanisms underlying cardiac injury in patients affected by COVID-19.

RECENT FINDINGS

The COVID-19 pandemic has primarily been associated with severe respiratory symptoms. However, emerging evidence has indicated that a significant number of COVID-19 patients also experience myocardial injury, leading to conditions such as acute myocarditis, heart failure, acute coronary syndrome, and arrhythmias. The incidence of myocardial injury is notably higher in patients with preexisting cardiovascular diseases. Myocardial injury often manifests with elevated levels of inflammation biomarkers, as well as abnormalities observed on electrocardiograms and echocardiograms. COVID-19 infection has been found to be associated with myocardial injury, which can be attributed to several pathophysiological mechanisms. These mechanisms include injury caused by hypoxia, resulting from respiratory compromise, a systemic inflammatory response triggered by the infection, and direct attack on the myocardium by the virus itself. Furthermore, the angiotensin-converting enzyme 2 (ACE2) receptor plays a crucial role in this process. Early recognition, prompt diagnosis, and a comprehensive understanding of the underlying mechanisms are essential for effectively managing and reducing the mortality associated with myocardial injury in COVID-19 patients.

The pattern of late gadolinium enhancement by cardiac MRI in fulminant myocarditis and its prognostic implication: a two-year follow-up study

Background

Myocardial fibrosis, as quantified by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR), provides valuable prognostic information for patients with myocarditis. However, due to the low incidence rate of fulminant myocarditis (FM) and accordingly small sample size, the knowledge about the role of LGE to patients with FM is limited.

Methods and results

A total of 44 adults with viral-FM receiving the Chinese treating regimen were included in this retrospective study. They were divided into the low LGE group and the high LGE group according to the ratio of LGE to left ventricular mass (LGE mass%). CMR exams and LGE were performed after hemodynamic assistance at discharge in all patients with FM. Routine echocardiography parameters and global longitudinal strain (GLS) at discharge and at 2-year follow-up were obtained and then compared. Both left ventricular ejection fraction (LVEF) and GLS showed no significant difference in both groups at discharge, whereas significant differences were observed at 2-year follow-up between two groups. Moreover, there were significant improvements of LVEF and GLS in the low LGE group, but not in the high LGE group during the 2-year period. Furthermore, LGE mass% was negatively correlated with GLS and LVEF.

Conclusions

There were two distinct forms of LGE presentation in patients with FM. Moreover, the cardiac function of patients with low LGE was significantly better than those with high LGE at 2-year follow-up. LGE mass% at discharge provided significant prognosis information about cardiac function of patients with FM.

High AST/ALT Ratio Is Associated with Cardiac Involvement in Acute COVID-19 Patients

Background and Objectives: We aimed to assess the effect of AST/ALT ratio on echocardiographic and cardiac magnetic resonance imaging (CMRI) parameters after COVID-19 patients recover. Materials and Methods: 87 patients with COVID-19 were included in the study. The patients were hospitalized with COVID-19 pneumonia, but the patients did not need intensive care unit follow-up or non-invasive mechanical ventilation support. After a discharge and two weeks following the positive swab test result, patients were considered eligible if they had any symptoms. Transthoracic echocardiography (TTE) was performed within 24 h prior to CMRI. The median value of AST/ALT ratio was found, and the study population was divided into two subgroups based on the median AST/ALT ratio value. The clinical features, blood test, TTE and CMRI results were compared between subgroups. Results: C-reactive protein, D-dimer and fibrinogen were found to be significantly higher in patients with high AST/ALT ratio. LVEF, TAPSE, S', and FAC were significantly lower in patients with high AST/ALT ratio. LV-GLS were significantly lower in patients with high AST/ALT ratio. In CMRI, native T1 mapping signal, native T2 mapping signal and extracellular volume raised significantly in patients with high AST/ALT ratio. Right ventricle stroke volume and right ventricle ejection fraction were significantly lower in patients with high AST/ALT ratio, but right ventricle end systolic volume was significantly higher in patients with high AST/ALT ratio. Conclusion: High AST/ALT ratio is related to impaired right ventricular function parameters with CMRI and echocardiography after recovery from acute COVID-19. Assessment of AST/ALT ratio at hospital admission may be used to assess the risk of cardiac involvement in COVID-19 disease, and these patients may require closer follow-up during and after the course of COVID-19.

Patients with Post-COVID-19 Vaccination Myocarditis Have More Favorable Strain in Cardiac Magnetic Resonance Than Those With Viral Myocarditis

There have been reports of myocarditis following vaccination against COVID-19. We sought to describe cardiac magnetic resonance (CMR) findings among pediatric patients. Retrospective review at a large academic center of patients clinically diagnosed with post-vaccine myocarditis (PVM) undergoing CMR. Data collected included parametric mapping, ventricular function, and degree of late gadolinium enhancement (LGE). Post-processing strain analysis was performed using feature tracking. Strain values, T1/T2 values, and ventricular function were compared to age- and gender-matched controls with viral myocarditis using a Wilcoxon Signed Rank test. Among 12 patients with presumed PVM, 11 were male and 11 presented after the second vaccination dose, typically within 4 days. All presented with chest pain and elevated troponin. 10 met MRI criteria for acute myocarditis. All had LGE typically seen in the lateral and inferior walls; only five had prolonged T1 values. 10 met criteria for edema based on skeletal muscle to myocardium signal intensity ratio and only 5 had prolonged T2 mapping values. Patients with PVM had greater short-axis global circumferential and radial strain, right ventricle function, and cardiac output when compared to those with viral myocarditis. Patients with PVM have greater short-axis global circumferential and radial strains compared to those with viral myocarditis. LGE was universal in our cohort. Signal intensity ratios between skeletal muscle and myocardium may be more sensitive in identifying edema than T2 mapping. Overall, the impact on myocardial strain by CMR is less significant in PVM compared to more classic viral myocarditis.

Comparative Cardiac Magnetic Resonance-Based Feature Tracking and Deep-Learning Strain Assessment in Patients Hospitalized for Acute Myocarditis

This study sought to examine the correlation between left ventricular (LV) myocardial feature tracking (FT) and deep learning-based strain (DLS) analysis in the diagnostic (CMRd) and follow-up (CMRf) cardiac magnetic resonance imaging of patients with acute myocarditis. The retrospective study included 17 patients with acute myocarditis and 20 healthy controls. The CMRd took place within 14 days of symptom onset, while the CMRf took place at least 2 months after the event. The global-circumferential FT (FTc) and global-circumferential DLS (DLSc) were analyzed. The continuous variables were compared using paired t-tests or the Wilcoxon test, whereas Pearson's test or Spearman's test was used to evaluate the correlation between the continuous variables. The time between the CMRd and CMRf was 5 months [3-11]. The LV ejection fraction (LVEF) was 55 ± 6 and 59 ± 4%, p = 0.008, respectively, and 94.1% of the patients showed late gadolinium enhancement (LGE) and myocardial edema on the CMRd. Significantly lower FTc (-16.1 ± 2.2% vs. -18.9 ± 1.9%, p = 0.001) and DLSc (-38.1 ± 5.2% vs. -41.3 ± 4.5%, p = 0.015) were observed with respect to the controls. Significant increases in the FTc (-16.1 ± 2.2 vs. -17.5 ± 1.9%, p = 0.016) and DLSc (-38.1 ± 5.2 vs. -39.8 ± 3.9%, p = 0.049) were found between the CMRd and CMRf, which were unrelated to the LGE. The LVEF correlated well with the FTc (r = 0.840) and DLSc (r = 0.760). Both techniques had excellent reproducibility, with high intra- (FTc = 0.980, DLSc = 1.000) and inter-observer (FTc = 0.970, DLSc = 0.980) correlation. There was correlation between the LV DLSc/FTc and LVEF in the patients with acute myocarditis according to the CMRd and CMRf.

Diastolic dysfunction assessed by cardiac magnetic resonance imaging tissue tracking on normal-thickness wall segments in hypertrophic cardiomyopathy

OBJECTIVES

Myocardial strain is reported to be a sensitive indicator of myocardial mechanical changes in patients with hypertrophic cardiomyopathy (HCM). The changes in the mechanics of the myocardium of normal wall thickness (< 12 mm) have yet to be well studied. This study aimed to evaluate the function of myocardial segments of normal thickness in patients with HCM.

METHODS

Sixty-three patients with HCM and 30 controls were retrospectively enrolled in this retrospective study. Cine imaging, native and post-contrast T1 maps, T2 maps, and late gadolinium enhancement were performed. In addition, regional myocardial strain was assessed by cardiac magnetic resonance-tissue tracking. Strain parameters were compared between the controls and HCM patients with segments of the myocardium of normal thickness. Subgroup analysis was conducted in obstructive and non-obstructive HCM. Lastly, p < 0.05 was considered statistically significant.

RESULTS

In normal-thickness myocardial segments of HCM (n = 716), diastolic peak strain rates (PSRs) were significantly lower than in the control group (n = 480) (radial, - 2.43 [- 3.36, - 1.78] vs. - 2.67 [- 3.58, - 1.96], p = 0.002; circumferential, 1.28 [1.01,1.60] vs. 1.39 [1.14, 1.78], p < 0.001; and longitudinal, 1.16 [0.75,1.51] vs. 1.28 [0.90, 1.71], p < 0.001). The normal-thickness segments showed no significant difference in systolic PSRs between HCM and the controls. In the subgroup analysis, significantly decreased diastolic PSRs were noted in both obstructive and non-obstructive HCM, compared with the controls (p < 0.05).

CONCLUSIONS

Diastolic changes in myocardial mechanics were observed in normal-thickness segments of HCM, occurring before morphological remodeling and systolic dysfunction developed. This finding contributed to a better understanding of the mechanical pathophysiology of HCM with preserved left ventricular ejection fraction. It may potentially aid in predicting disease progression and risk stratification.

Role of cardiovascular magnetic resonance imaging in COVID-19 recovered patients: A short-term follow-up study

OBJECTIVE

Cardiac involvement in recovered COVID-19 patients assessed by cardiac magnetic resonance imaging (MRI).

METHODS

Subjects recently recovered from COVID-19 and with an abnormal left ventricular global longitudinal strain were enrolled. Cardiac MRI in all the enrolled subjects was done at baseline (within 30-90 days following recovery from COVID-19) with a follow-up scan at 6 months in individuals with an abnormal baseline scan. Additionally, 20 age-and sex-matched individuals were enrolled as healthy controls (HCs).

RESULTS

All the 30 enrolled subjects were symptomatic during active COVID-19 disease and were categorized as mild: 11 (36.7%), moderate: 6 (20%), and severe: 13 (43.3%). Of the 30 patients, 16 (53.3%) had abnormal CMR findings. Myocardial edema was reported in 12 (40%) patients while 10 (33.3%) had late gadolinium enhancement (LGE). No difference was observed in terms of conventional left ventricular (LV) parameters; however, COVID-19-recovered patients had significantly lower right ventricular (RV) ejection fraction, RV stroke volume, and RV cardiac index compared to HCs. Follow-up scan was abnormal in 4/16 (25%) with LGE persisting in three patients (who had severe COVID-19 [3/4;75%]). Subjects with severe COVID-19 had a greater frequency of LGE (53.8%) and myocardial edema (61.5%) as compared to mild and moderate cases. Myocardial T1 (1284 ± 43.8 ms vs. 1147.6 ± 68.4 ms; p &lt; .0001) and T2 values (50.8 ± 16.7 ms vs. 42.6 ± 3.6 ms; p = .04) were significantly higher in post COVID-19 subjects compared to HCs. Similarly, T1 and T2 values of severe COVID-19 patients were significantly higher compared to mild and moderate cases.

CONCLUSIONS

An abnormal CMR was seen in half of the recovered patients with persistent abnormality in one-fourth at 6 months. Our study suggests a need for closer follow-up among recovered subjects in order to evaluate for long-term cardiovascular sequelae. COVID-19 causes structural changes in the myocardium in a small segment of patients with partial spontaneous resolution.

Applying quantitative CMR parameters for detecting myocardial lesion in immune checkpoint inhibitors-associated myocarditis

PURPOSE

Sparse researches evaluated the quantitative cardiovascular magnetic resonance (CMR) parameters for immune checkpoint inhibitors (ICI)-associated myocarditis. We aimed to apply quantitative CMR mappings and late gadolinium enhancement (LGE) extent for detecting ICI-associated myocarditis.

METHOD

The retrospective study included patients with ICI-associated myocarditis and CMR examination from August 2018 to August 2021 in our hospital. ICI-associated myocarditis was clinically diagnosed based on the clinical criteria by European Society of Cardiology guidelines. The multiparametric CMR images including T2 mapping and black blood T2-weighted images were used to evaluate myocardial edema. The myocardial edema ratio (ER) ≥ 2.0 was applied for determining myocardial edema on T2-weighted images.

RESULTS

56 patients with ICI-associated myocarditis were included. The global T2 value and native T1 value of patients with ICI-associated myocarditis were significantly higher than the reference ranges in our hospital (p < 0.05). The rate of elevated global T2 value (92%) was significantly higher than those of abnormal native T1 value (73%), ER (52%) and LGE presence (68%) in patients with ICI-associated myocarditis (p < 0.05). The LGE extent and left ventricular ejection fraction of patients with ICI-associated myocarditis were 10.38 ± 9.64% and 56.42 ± 8.54%, respectively. LGE extent inversely correlated with left ventricular ejection fraction (r = -0.38, p = 0.004) but positively correlated with native T1 value (r = 0.28, p < 0.04) and extracellular volume (r = 0.50, p = 0.001).

CONCLUSIONS

T2 mapping could detect higher rate of patients with ICI-associated myocarditis than native T1 mapping, ER and LGE presence. LGE extent inversely correlated with left ventricular ejection fraction but positively correlated with native T1 value and extracellular volume in patients with ICI-associated myocarditis.

Multimodality imaging in acute myocarditis

The diagnosis of acute myocarditis often involves several noninvasive techniques that can provide information regarding volumes, ejection fraction, and tissue characterization. In particular, echocardiography is extremely helpful for the evaluation of biventricular volumes, strain and ejection fraction. Cardiac magnetic resonance, beyond biventricular volumes, strain, and ejection fraction allows to characterize myocardial tissue providing information regarding edema, hyperemia, and fibrosis. Contemporary cardiac computed tomography angiography (CCTA) can not only be extremely important for the assessment of coronary arteries, pulmonary arteries and aorta but also tissue characterization using CCTA can be an additional tool that can explain chest pain with a diagnosis of myocarditis.

Cardiovascular magnetic resonance imaging patterns of acute COVID-19 mRNA vaccine-associated myocarditis in young male patients: A first single-center experience

Background

The risk of myocarditis after mRNA vaccination against COVID-19 has emerged recently. Current evidence suggests that young male patients are predominantly affected. In the majority of the cases, only mild symptoms were observed. However, little is known about cardiac magnetic resonance (CMR) imaging patterns in mRNA-related myocarditis and their differences when compared to classical viral myocarditis in the acute phase of inflammation.

Methods and results

In total, 10 mRNA vaccination-associated patients with myocarditis were retrospectively enrolled in this study and compared to 10 patients suffering from viral myocarditis, who were matched for age, sex, comorbidities, and laboratory markers. All patients (n = 20) were hospitalized and underwent a standardized clinical examination, as well as an echocardiography and a CMR. Both, clinical and imaging findings and, in particular, functional and volumetric CMR assessments, as well as detailed tissue characterization using late gadolinium enhancement and T1 + T2-weighted sequences, were compared between both groups. The median age of the overall cohort was 26 years (group 1: 25.5; group 2: 27.5; p = 0.57). All patients described chest pain as the leading reason for their initial presentation. CMR volumetric and functional parameters did not differ significantly between both groups. In all cases, the lateral left ventricular wall showed late gadolinium enhancement without significant differences in terms of the localization or in-depth tissue characterization (late gadolinium enhancement [LGE] enlargement: group 1: 5.4%; group 2: 6.5%; p = 0.14; T2 global/maximum value: group 1: 38.9/52 ms; group 2: 37.8/54.5 ms; p = 0.79 and p = 0.80).

Conclusion

This study yielded the first evidence that COVID-19 mRNA vaccine-associated myocarditis does not show specific CMR patterns during the very acute stage in the most affected patient group of young male patients. The observed imaging markers were closely related to regular viral myocarditis in our cohort. Additionally, we could not find any markers implying adverse outcomes in this relatively little number of patients; however, this has to be confirmed by future studies that will include larger sample sizes.

Patterns of cardiovascular magnetic resonance inflammation in acute myocarditis from South Asia and Middle East

Background

Cardiovascular magnetic resonance (CMR) is the test of choice for diagnosis and risk stratification of myocardial inflammation in acute viral myocarditis. The objective of this study was to assess patterns of CMR inflammation in a cohort of acute myocarditis patients from Northern Africa, Asia, and the Middle East using unsupervised machine learning.

Methods

A total of 169 racially and ethnically diverse adults (≥18 years of age) with CMR confirmed acute myocarditis were studied. The primary outcome was a combined clinical endpoint of cardiac death, arrhythmia, and dilated cardiomyopathy. Machine learning was used for exploratory analysis to identify patterns of CMR inflammation.

Results

Our cohort was diverse with 25% from Northern Africa, 33% from Southern Asia, and 28% from Western Asia/the Middle East. Twelve patients met the combined clinical endpoint – 3 had arrythmia, 8 had dilated cardiomyopathy, and 1 died. Patients who met the combined endpoint had increased anterior (p = 0.034) and septal (p = 0.042) late gadolinium enhancement (LGE). Multivariable logistic regression, adjusted for age, gender, and BMI, found that patients from Southern Asia (p = 0.041) and the Middle East (p = 0.043) were independently associated with lateral LGE. Unsupervised machine learning and factor analysis identified two distinct CMR patterns of inflammation, one with increased LGE and the other with increased myocardial T1/T2.

Conclusions

We found that anteroseptal inflammation is associated with worsened outcomes. Using machine learning, we identified two patterns of myocardial inflammation in acute myocarditis from CMR in a racially and ethnically diverse group of patients from Southern Asia, Northern Africa, and the Middle East.

The Pathogenesis and Long-Term Consequences of COVID-19 Cardiac Injury

•

COVID-19 myocardial injury results from immune and hypercoagulability responses.

•

Long-term cardiac consequences of COVID-19 include structural and functional changes.

•

Myocarditis after COVID-19 vaccination is uncommon (highest risk in teenage males).

•

Larger population-based studies are necessary to validate these early results.

The mechanisms of coronavirus disease-2019 (COVID-19)–related myocardial injury comprise both direct viral invasion and indirect (hypercoagulability and immune-mediated) cellular injuries. Some patients with COVID-19 cardiac involvement have poor clinical outcomes, with preliminary data suggesting long-term structural and functional changes. These include persistent myocardial fibrosis, edema, and intraventricular thrombi with embolic events, while functionally, the left ventricle is enlarged, with a reduced ejection fraction and new-onset arrhythmias reported in a number of patients. Myocarditis post-COVID-19 vaccination is rare but more common among young male patients. Larger studies, including prospective data from biobanks, will be useful in expanding these early findings and determining their validity.

Emerging Role of Cardiac Magnetic Resonance Imaging in Diagnosing Myocarditis: A Blunder or The Way To Get the Problem Sorted?

Acute myocarditis is a disease affecting the myocardial tissue, which is caused by infections, rheumatic diseases, especially sarcoidosis, or certain therapies. Its diagnosis may be difficult, owing to its variable clinical presentation. In this setting, cardiac magnetic resonance plays a pivotal role in detecting myocardial inflammation through qualitative, semiquantitative, and quantitative parameters, in particular with the new quantitative techniques such as T1 and T2 mapping, combined or not with late gadolinium enhancement evaluation. This is in accordance with the revised Lake Louise criteria. In this review, the emerging role of the new cutting-edge cardiac magnetic resonance imaging techniques in diagnosing myocarditis is extensively presented.

Cardiac magnetic resonance in recovering COVID-19 patients. Feature tracking and mapping analysis to detect persistent myocardial involvement

BACKGROUND

Post-COVID-19 patients may incur myocardial involvement secondary to systemic inflammation. Our aim was to detect possible oedema/diffuse fibrosis using cardiac magnetic resonance imaging (CMR) mapping and to study myocardial deformation of the left ventricle (LV) using feature tracking (FT).

METHODS

Prospective analysis of consecutively recruited post-COVID-19 patients undergoing CMR. T1 and T2 mapping sequences were acquired and FT analysis was performed using 2D steady-state free precession cine sequences. Statistical significance was set to p < 0.05.

RESULTS

Included were 57 post-COVID-19 patients and 20 healthy controls, mean age 59 ± 15 years, men 80.7%. The most frequent risk factors were hypertension (33.3%) and dyslipidaemia (36.8%). The contact-to-CMR interval was 81 ± 27 days. LV ejection fraction (LVEF) was 61 ± 10%. Late gadolinium enhancement (LGE) was evident in 26.3% of patients (19.3%, non-ischaemic). T2 mapping values (suggestive of oedema) were higher in the study patients than in the controls (50.9 ± 4.3 ms vs 48 ± 1.9 ms, p < 0.01). No between-group differences were observed for native T1 nor for circumferential strain (CS) or radial strain (RS) values (18.6 ± 3.3% vs 19.2 ± 2.1% (p = 0.52) and 32.3 ± 8.1% vs 33.6 ± 7.1% (p = 0.9), respectively). A sub-group analysis for the contact-to-CMR interval (<8 weeks vs ≥ 8 weeks) showed that FT-CS (15.6 ± 2.2% vs 18.9 ± 2.6%, p < 0.01) and FT-RS (24.9 ± 5.8 vs 33.5 ± 7.2%, p < 0.01) values were lower for the shorter interval.

CONCLUSIONS

Post-COVID-19 patients compared to heathy controls had raised T2 values (related to oedema), but similar native T1, FT-CS and FT-RS values. FT-CS and FT-RS values were lower in post-COVID-19 patients undergoing CMR after < 8 weeks compared to ≥ 8 weeks.

Cardiac Magnetic Resonance Imaging Findings in 2954 COVID-19 Adult Survivors: A Comprehensive Systematic Review

Background

Recent studies have utilized MRI to determine the extent to which COVID‐19 survivors may experience cardiac sequels after recovery.

Purpose

To systematically review the main cardiac MRI findings in COVID‐19 adult survivors.

Study type

Systematic review.

Subjects

A total of 2954 COVID‐19 adult survivors from 16 studies.

Field Strength/sequence

Late gadolinium enhancement (LGE), parametric mapping (T1‐native, T2, T1‐post (extracellular volume fraction [ECV]), T2‐weighted sequences (myocardium/pericardium), at 1.5 T and 3  T.

Assessment

A systematic search was performed on PubMed, Embase, and Google scholar databases using Boolean operators and the relevant key terms covering COVID‐19, cardiac injury, CMR, and follow‐up. MRI data, including (if available) T1, T2, extra cellular volume, presence of myocardial or pericardial late gadolinium enhancement (LGE) and left and right ventricular ejection fraction were extracted.

Statistical Tests

The main results of the included studies are summarized. No additional statistical analysis was performed.

Results

Of 1601 articles retrieved from the initial search, 12 cohorts and 10 case series met our eligibility criteria. The rate of raised T1 in COVID‐19 adult survivors varied across studies from 0% to 73%. Raised T2 was detected in none of patients in 4 out of 15 studies, and in the remaining studies, its rate ranged from 2% to 60%. In most studies, LGE (myocardial or pericardial) was observed in COVID‐19 survivors, the rate ranging from 4% to 100%. Myocardial LGE mainly had nonischemic patterns. None of the cohort studies observed myocardial LGE in “healthy” controls. Most studies found that patients who recovered from COVID‐19 had a significantly greater T1 and T2 compared to participants in the corresponding control group.

Data Conclusion

Findings of MRI studies suggest the presence of myocardial and pericardial involvement in a notable number of patients recovered from COVID‐19.

Level of Evidence

3

Technical Efficacy Stage

3

Cardiac Imaging in Athlete's Heart: The Role of the Radiologist

Athlete’s heart (AH) is the result of morphological and functional cardiac modifications due to long-lasting athletic training. Athletes can develop very marked structural myocardial changes, which may simulate or cover unknown cardiomyopathies. The differential diagnosis between AH and cardiomyopathy is necessary to prevent the risk of catastrophic events, such as sudden cardiac death, but it can be a challenging task. The improvement of the imaging modalities and the introduction of the new technologies in cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) can allow overcoming this challenge. Therefore, the radiologist, specialized in cardiac imaging, could have a pivotal role in the differential diagnosis between structural adaptative changes observed in the AH and pathological anomalies of cardiomyopathies. In this review, we summarize the main CMR and CCT techniques to evaluate the cardiac morphology, function, and tissue characterization, and we analyze the imaging features of the AH and the key differences with the main cardiomyopathies.

Fulminant myocarditis: a comprehensive review from etiology to treatments and outcomes

Fulminant myocarditis (FM) is characterized by a rapid progressive decline in cardiac function and a high mortality rate. Since the first report of FM patients in the 1980s, several clinical trials and research studies have been published increasing our knowledge regarding FM. Currently, the diagnosis of FM depends on various techniques including electrocardiography, echocardiography, endomyocardial biopsy, and cardiac magnetic resonance. The development of mechanical circulation support (MCS) devices and progress in our understanding of the pathophysiological mechanisms underlying FM, treatment regimens have evolved from simple symptomatic treatment to a life support-based comprehensive treatment approach. The core mechanism underlying the development of FM is the occurrence of an inflammatory cytokine storm. This review provides a comprehensive account of the current understanding of FM pathophysiology and knowledge regarding its etiology, pathophysiology, treatments, and outcomes.

Use of the new Lake Louise Criteria improves CMR detection of atypical forms of acute myocarditis

The purpose of our study was to compare diagnostic performance of old and new Lake Louise Criteria (oLLC and nLLC) among different clinical presentations: infarct-like (IL), cardiomyopathic (CM) and arrhythmic (AR). 102 patients with clinical suspicion of acute myocarditis underwent cardiac magnetic resonance (CMR) on a 1.5 T scanner. Protocol included cine-SSFP, T2-weighted STIR, T2 mapping, early and late gadolinium enhancement and T1 mapping acquired before and after gadolinium administration. The degree of agreement has been calculated with Cohen's K test. 42 patients also underwent endomyocardial biopsy (EMB). IL onset was present in 54/102 patients, CM in 28/102 and AR in 20/102. nLLC were positive in 58.3% of the patients, while oLLC in 37.9%, k = 0.57 (IC: 0.428-0.713). The degree of agreement between nLLC and oLLC was 0.49 (IC: 0.111-0.876) for AR onset (nLLC positive in 35% vs oLLC in 15%), 0.25 (IC: 0.035-0.459) for CM pattern (nLLC positive in 60.7% vs oLLC 17.9%) and 0.73 (IC: 0.543-0.912) for IL presentation (nLLC positive in 66.7% vs oLLC in 57.4%). Diagnostic accuracy was 75% for both nLLC and oLLC among IL onset, and 41.6% for oLLC vs 66.7% for nLLC, as regards CM clinical presentation. nLLC have improved diagnostic performance of CMR for the diagnosis of acute myocarditis, in particular for atypical clinical presentation.

Cardiac Involvement in Patients Recovered From COVID-2019 Identified Using Magnetic Resonance Imaging

Objectives

This study evaluated cardiac involvement in patients recovered from coronavirus disease-2019 (COVID-19) using cardiac magnetic resonance (CMR).

Background

Myocardial injury caused by COVID-19 was previously reported in hospitalized patients. It is unknown if there is sustained cardiac involvement after patients' recovery from COVID-19.

Methods

Twenty-six patients recovered from COVID-19 who reported cardiac symptoms and underwent CMR examinations were retrospectively included. CMR protocols consisted of conventional sequences (cine, T2-weighted imaging, and late gadolinium enhancement [LGE]) and quantitative mapping sequences (T1, T2, and extracellular volume [ECV] mapping). Edema ratio and LGE were assessed in post-COVID-19 patients. Cardiac function, native T1/T2, and ECV were quantitatively evaluated and compared with controls.

Results

Fifteen patients (58%) had abnormal CMR findings on conventional CMR sequences: myocardial edema was found in 14 (54%) patients and LGE was found in 8 (31%) patients. Decreased right ventricle functional parameters including ejection fraction, cardiac index, and stroke volume/body surface area were found in patients with positive conventional CMR findings. Using quantitative mapping, global native T1, T2, and ECV were all found to be significantly elevated in patients with positive conventional CMR findings, compared with patients without positive findings and controls (median [interquartile range]: native T1 1,271 ms [1,243 to 1,298 ms] vs. 1,237 ms [1,216 to 1,262 ms] vs. 1,224 ms [1,217 to 1,245 ms]; mean ± SD: T2 42.7 ± 3.1 ms vs. 38.1 ms ± 2.4 vs. 39.1 ms ± 3.1; median [interquartile range]: 28.2% [24.8% to 36.2%] vs. 24.8% [23.1% to 25.4%] vs. 23.7% [22.2% to 25.2%]; p = 0.002; p < 0.001, and p = 0.002, respectively).

Conclusions

Cardiac involvement was found in a proportion of patients recovered from COVID-19. CMR manifestation included myocardial edema, fibrosis, and impaired right ventricle function. Attention should be paid to the possible myocardial involvement in patients recovered from COVID-19 with cardiac symptoms.