Cardiac Magnetic Resonance Imaging Findings and Clinical Features of COVID-19 Vaccine-Associated Myocarditis, Compared With Those of Other Types of Myocarditis

BACKGROUND

To compare the clinical and cardiac magnetic resonance (CMR) imaging findings of coronavirus disease 2019 (COVID-19) vaccine-associated myocarditis (VAM) with those of other types of myocarditis.

METHODS

From January 2020 to March 2022, a total of 39 patients diagnosed with myocarditis via CMR according to the Modified Lake Louise criteria were included in the present study. The patients were classified into two groups based on their vaccination status: COVID-19 VAM and other types of myocarditis not associated with COVID-19 vaccination. Clinical outcomes, including the development of clinically significant arrhythmias, sudden cardiac arrest, and death, and CMR imaging features were compared between COVID-19 VAM and other types of myocarditis.

RESULTS

Of the 39 included patients (mean age, 39 years ± 16.4 [standard deviation]; 23 men), 23 (59%) had COVID-19 VAM and 16 (41%) had other types of myocarditis. The occurrence of clinical adverse events did not differ significantly between the two groups. As per the CMR imaging findings, the presence and dominant pattern of late gadolinium enhancement did not differ significantly between the two groups. The presence of high native T1 or T2 values was not significantly different between the two groups. Although the native T1 and T2 values tended to be lower in COVID-19 VAM than in other types of myocarditis, there were no statistically significant differences between the native T1 and T2 values in the two groups.

CONCLUSION

The present study demonstrated that the CMR imaging findings and clinical outcomes of COVID-19 VAM did not differ significantly from those of other types of myocarditis during hospitalization.

Myocardial Fibrosis in Congenital Heart Disease and the Role of MRI

Progress in the field of congenital heart surgery over the last century can only be described as revolutionary. Recent improvements in patient outcomes have been achieved through refinements in perioperative care. In the current and future eras, the preservation and restoration of myocardial health, beginning with the monitoring of tissue remodeling, will be central to improving cardiac outcomes. Visualization and quantification of fibrotic myocardial remodeling is one of the greatest assets that cardiac MRI brings to the field of cardiology, and its clinical use within the field of congenital heart disease (CHD) has been an area of particular interest in the last few decades. This review summarizes the physical underpinnings of myocardial tissue characterization in CHD, with an emphasis on T1 parametric mapping and late gadolinium enhancement. It describes methods and suggestions for obtaining images, extracting quantitative and qualitative data, and interpreting the results for children and adults with CHD. The tissue characterization observed in different lesions is used to examine the causes and pathomechanisms of fibrotic remodeling in this population. Similarly, the clinical consequences of elevated imaging biomarkers of fibrosis on patient health and outcomes are explored. Keywords: Pediatrics, MR Imaging, Cardiac, Heart, Congenital, Tissue Characterization, Congenital Heart Disease, Cardiac MRI, Parametric Mapping, Fibrosis, Late Gadolinium Enhancement © RSNA, 2023.

Mitochondrial Cardiomyopathy: Distinctive Cardiac Phenotype Detected with Cardiovascular MRI

Left ventricular hypertrophy (LVH) has a broad differential diagnosis. Pathogenic variants of mitochondrial DNA are a rare cause of LVH, and cardiac MRI is a powerful technique that may aid in differentiating such rare causes. This case report presents three siblings with a pathogenic variant of the mitochondrially encoded tRNA isoleucine (MT-TI) gene. A distinctive cardiac phenotype was detected with cardiac MRI. Extensive LVH and dilatation and decreased ejection fraction were observed with a pattern of increased T2 signal and extensive late gadolinium enhancement, which was remarkably consistent among all three siblings. Keywords: Cardiomyopathies, MR Imaging, Hypertrophic Cardiomyopathy, Mitochondrial, Inherited Cardiomyopathy, Left Ventricular Hypertrophy, Cardiovascular MRI, Late Gadolinium Enhancement Supplemental material is available for this article. © RSNA, 2023.

Non-LGE Cardiac Magnetic Resonance Imaging in Patients with Cardiac Amyloidosis

Cardiac involvement is the leading cause of death in patients with cardiac amyloidosis. Early recognition is crucial as it can significantly change the course of the disease. Until now, the imaging modality of choice for diagnosing cardiac amyloidosis has been cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE). LGE-CMR in patients with cardiac amyloidosis reveals characteristic LGE patterns that lead to a diagnosis while also correlating well with disease prognosis. However, LGE-CMR has numerous drawbacks that the newer CMR modality, T1 mapping, aims to improve. T1 mapping can be further subdivided into native T1 mapping, which does not require the use of contrast, and ECV measurement, which requires the use of contrast. Numerous T1 mapping techniques have been developed, each one with its own advantages and disadvantages when it comes to procedure difficulty and image quality. A literature review to identify relevant published articles was performed by two authors. This review aimed to present the value of T1 mapping in diagnosing cardiac amyloidosis, quantifying the amyloid burden, and evaluating the prognosis of patients with amyloidosis with cardiac involvement.

T1 Mapping Values May Be Associated with Early Myocardial Involvement in Young Patients with Wilson Disease

In young Asian patients with Wilson disease and no cardiac abnormalities or late gadolinium enhancement, cardiac MRI depicted elevated native T1, T2, and extracellular volume, suggesting early cardiac involvement.

Combination of late gadolinium enhancement and genotype improves prediction of prognosis in non-ischemic dilated cardiomyopathy

Aims

Genotype and left ventricular scar on cardiac magnetic resonance (CMR) are increasingly recognized as risk markers for adverse outcomes in non‐ischaemic dilated cardiomyopathy (DCM). We investigated the combined influence of genotype and late gadolinium enhancement (LGE) in assessing prognosis in a large cohort of patients with DCM.

Methods and results

Outcomes of 600 patients with DCM (53.3 ± 14.1 years, 66% male) who underwent clinical CMR and genetic testing were retrospectively analysed. The primary endpoints were end‐stage heart failure (ESHF) and malignant ventricular arrhythmias (MVA). During a median follow‐up of 2.7 years (interquartile range 1.3–4.9), 24 (4.00%) and 48 (8.00%) patients had ESHF and MVA, respectively. In total, 242 (40.3%) patients had pathogenic/likely pathogenic variants (positive genotype) and 151 (25.2%) had LGE. In survival analysis, positive LGE was associated with MVA and ESHF (both, p < 0.001) while positive genotype was associated with ESHF (p = 0.034) but not with MVA (p = 0.102). Classification of patients according to genotype (G+/G−) and LGE presence (L+/L−) revealed progressively increasing events across L−/G−, L−/G+, L+/G− and L+/G+ groups and resulted in optimized MVA and ESHF prediction (p < 0.001 and p = 0.001, respectively). Hazard ratios for MVA and ESHF in patients with either L+ or G+ compared with those with L−/G− were 4.71 (95% confidence interval: 2.11–10.50, p < 0.001) and 7.92 (95% confidence interval: 1.86–33.78, p < 0.001), respectively.

Conclusion

Classification of patients with DCM according to genotype and LGE improves MVA and ESHF prediction. Scar assessment with CMR and genotyping should be considered to select patients for primary prevention implantable cardioverter‐defibrillator placement.

High-resolution Free-breathing late gadolinium enhancement Cardiovascular magnetic resonance to diagnose myocardial injuries following COVID-19 infection

PURPOSE

High-resolution free-breathing late gadolinium enhancement (HR-LGE) was shown valuable for the diagnosis of acute coronary syndromes with non-obstructed coronary arteries. The method may be useful to detect COVID-related myocardial injuries but is hampered by prolonged acquisition times. We aimed to introduce an accelerated HR-LGE technique for the diagnosis of COVID-related myocardial injuries.

METHOD

An undersampled navigator-gated HR-LGE (acquired resolution of 1.25 mm3) sequence combined with advanced patch-based low-rank reconstruction was developed and validated in a phantom and in 23 patients with structural heart disease (test cohort; 15 men; 55 ± 16 years). Twenty patients with laboratory-confirmed COVID-19 infection associated with troponin rise (COVID cohort; 15 men; 46 ± 24 years) prospectively underwent cardiovascular magnetic resonance (CMR) with the proposed sequence in our center. Image sharpness, quality, signal intensity differences and diagnostic value of free-breathing HR-LGE were compared against conventional breath-held low-resolution LGE (LR-LGE, voxel size 1.8x1.4x6mm).

RESULTS

Structures sharpness in the phantom showed no differences with the fully sampled image up to an undersampling factor of x3.8 (P > 0.5). In patients (N = 43), this acceleration allowed for acquisition times of 7min21s ± 1min12s at 1.25 mm3 resolution. Compared with LR-LGE, HR-LGE showed higher image quality (P = 0.03) and comparable signal intensity differences (P > 0.5). In patients with structural heart disease, all LGE-positive segments on LR-LGE were also detected on HR-LGE (80/391) with 21 additional enhanced segments visible only on HR-LGE (101/391, P < 0.001). In 4 patients with COVID-19 history, HR-LGE was definitely positive while LR-LGE was either definitely negative (1 microinfarction and 1 myocarditis) or inconclusive (2 myocarditis).

CONCLUSIONS

Undersampled free-breathing isotropic HR-LGE can detect additional areas of late enhancement as compared to conventional breath-held LR-LGE. In patients with history of COVID-19 infection associated with troponin rise, the method allows for detailed characterization of myocardial injuries in acceptable scan times and without the need for repeated breath holds.

Incremental value of Late Gadolinium Enhancement by Cardiac MRI in risk stratification of heart failure patients with moderate and severe LV dysfunction

Objective

This is a prospective study of patients with LVEF ≤40%, with the objective of correlating CV events to LGE detected and quantified by CMRI.

Methods

Heart Failure (HF) patients with LVEF <40% who underwent CMRI were included. LGE volume of ≥6% of the myocardial volume was considered significant. Data of appropriate ICD shocks, CV hospitalizations and mortality were recorded.

Results

There were 133 HF (72 ICM & 62 NIDCM) patients with a mean age of 54 ± 12 years, mean LVEF of 34 ± 6% and a follow up of 24 ± 3 months. Totally 46 CV events were recorded in 30 patients, 44 in LGE +ve & 2 in LGE -ve groups (HR 17.8, 95% CI-8.03-39.3, P = 0.000095). All the 7 deaths were in LGE +ve group. CV events were 22 (30.5%) in ICM group and 8 (13.1%) in NIDCM group (p = 0.03). All the 22 ICM patients and 6 of the 8 NIDCM with CV events were LGE +ve. The distribution of CV events amongst LGE +ve and LGE -ve were 35 vs 0 (ICM) and 9 vs 2 (NIDCM); p < 0.005.CV events in LVEF ≤ 30% group, were seen in 19 (47.5%) vs 1 (5.8%) in LGE +ve vs LGE -ve and no of events were 29 vs 1 (p = 0.003). In those with LVEF >30% the corresponding figures were 9 (22.5%) vs 1 (2.8%) and 15 vs 1 respectively (p = 0.02).

Conclusion

Demonstration of significant LGE by CMRI indicates high risk occurrence of CV events (CV hospitalization, appropriate shocks and total mortality) in NIDCM & ICM patients with LVEF < 40%.

Impact of Late Gadolinium Enhancement on mortality, sudden death and major adverse cardiovascular events in ischemic and nonischemic cardiomyopathy: A systematic review and meta-analysis

BACKGROUND

The central role of left ventricular ejection fraction (LVEF) as the definitive risk marker of adverse outcomes in ischemic and nonischemic cardiomyopathy is increasingly uncertain. The current study aimed to conduct a systematic review and meta-analysis with the objective of evaluating the prognostic importance of Late Gadolinium Enhancement (LGE) in ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) on the key endpoints of all-cause mortality, cardiovascular mortality and sudden death.

METHODS

The study was prospectively registered in PROPSERO (CRD 42016039034). Electronic databases and reference lists were searched for studies evaluating the impact of LGE-CMR on all-cause mortality, cardiovascular mortality, ventricular arrhythmia or sudden death, or major adverse cardiovascular events. Data were extracted from 36 studies including n=7882 patients.

RESULTS

LGE was strongly associated with all-cause mortality HR 2.96 (95%CI: 2.37, 3.70, P<0.001), cardiovascular mortality HR 3.27 (95% CI: 2.05, 5.22, P<0.001), ventricular arrhythmia and sudden cardiac death HR 3.76 (95% CI: 3.14, 4.52, P<0.001), and major adverse cardiovascular events HR 3.24 (95% CI: 2.32, 4.52, P<0.001). In subgroup analyses, LGE was associated with all-cause mortality and cardiovascular mortality in both LVEF≤35% and LVEF>35% patients (P<0.001 all endpoints), as well as in nonischemic and ischemic cardiomyopathy.

CONCLUSION

Late Gadolinium Enhancement (LGE) in CMR predicts all-cause mortality, cardiovascular mortality, ventricular arrhythmia and sudden death, and major adverse cardiovascular events, independent of LVEF. Future trials of investigational therapies in NICM and ICM should consider the utilization of LGE to identify patients at risk of adverse outcomes.

Long-term prognostic value of combined free triiodothyronine and late gadolinium enhancement in nonischemic dilated cardiomyopathy

BACKGROUND

Thyroid dysfunction and myocardial fibrosis are both associated with cardiovascular events in patients with dilated cardiomyopathy (DCM).

HYPOTHESIS

The combination of thyroid hormone (TH) and myocardial fibrosis (detected by late gadolinium enhancement [LGE]) is an independent and incremental predictor of adverse events in DCM.

METHODS

We consecutively enrolled 220 idiopathic DCM patients with thyroid function and LGE assessment at Fuwai Hospital (China) from January 2010 to October 2011 and followed up through December 2015. Patients were divided into 4 groups according to the presence or absence of LGE and FT3 value (median level of 2.79 pg/mL): LGE-positive + FT3 < 2.79 pg/mL, LGE-positive + FT3 ≥ 2.79 pg/mL, LGE-negative + FT3 < 2.79 pg/mL, and LGE-negative + FT3 ≥ 2.79 pg/mL.

RESULTS

During a median follow-up of 61 months, 56 patients (25.5%) died, with 27/56 (48.2%), 8/45 (17.8%), 12/54 (22.2%), and 9/65 (13.8%) among 4 groups (P = 0.009), respectively. Multivariable Cox regression analysis identified LGE-positive and FT3 < 2.79 pg/mL as a significant independent predictor of all-cause mortality (hazard ratio: 2.893, 95% confidence interval: 1.323-6.326, P = 0.008). Combining the predictive value of FT3 and LGE status significantly improved risk reclassification for all-cause mortality, as indicated by the net reclassification improvement (0.28; P = 0.005) and integrated discrimination improvement (0.058; P = 0.001).

CONCLUSIONS

The findings suggest that the combination of FT3 and LGE yielded a more accurate predictive value for long-term prognosis in patients with DCM, which may improve patient selection for intensive interventions.

Cardiac Magnetic Resonance Predictor of Ventricular Function after Surgical Coronary Revascularization

We evaluated echocardiographic changes of left ventricular (LV) function in coronary artery bypass grafting (CABG) patients with LV dysfunction, and examined cardiac magnetic resonance (CMR) parameters associated with improved LV function. Seventy-seven CABG patients presenting with decreased LV ejection fraction (LVEF, ≤ 35%) and who underwent preoperative gadolinium-enhanced CMR were enrolled. A 16-segment model was used to analyze CMR imaging. A viable myocardial segment was defined as ≤ 50% transmural extent of late gadolinium enhancement. Serial echocardiographic examinations were performed preoperatively, pre-discharge (median 6 days), and during postoperative year 1 (median 11 months) in 70 patients. Predictors of absolute increase in LVEF (≥ 5%) and proportional changes in LVEF were analyzed. Serial echocardiography demonstrated that LVEF measured 28.6% ± 5.4% preoperatively, 31.5% ± 8.0% median 6 days, and 42.1% ± 10.5% median 11 months postoperatively. Absolute increase of LVEF was observed in 27 patients at pre-discharge and in 24 patients by median 11 months. Proportional changes in LVEF at postoperative median 6 days and 11 months were 14% ± 28% and 57% ± 45%, respectively. The median number of viable myocardial segments was 14 (range, 9-16) in the 16 segment CMR model. Multivariable models demonstrated that the median number of overall viable myocardial segments (≥ 14) in preoperative CMR was associated with absolute increase (P = 0.046) and proportional changes (P = 0.005) in LVEF. In conclusion, the number of viable myocardial segments (≥ 14) in preoperative CMR predicted LV function improvement after CABG in patients with LV dysfunction.

ESC sudden-death risk model in hypertrophic cardiomyopathy: Incremental value of quantitative contrast-enhanced CMR in intermediate-risk patients

BACKGROUND

Hypertrophic cardiomyopathy (HCM) remains the most common cause of sudden cardiac death (SCD) in the young; however, current strategies do not identify all HCM patients at risk. A novel validated algorithm was proposed by the last European Society of Cardiology guidelines to guide implantable cardioverter-defibrillator (ICD) therapy. Recently, extensive myocardial fibrosis was independently associated with increased risk of SCD events. This study aimed to establish the relation between myocardial fibrosis (late gadolinium enhancement [LGE] extension) and the novel SCD risk-prediction model in a real population of HCM to evaluate its potential additional value in the different risk groups.

HYPOTHESIS

There is a significant association between LGE extension and the novel SCD risk calculator that may help conflicting ICD decisions.

METHODS

Seventy-seven patients with HCM underwent routine clinical evaluation, echocardiography, and cardiac magnetic resonance study. Their SCD risk at 5 years was calculated using the new model.

RESULTS

Extension of LGE positively correlated with SCD risk prediction (r = 0.7, P < 0.001). Low-, intermediate-, and high-risk groups according to the model showed significantly different extent of LGE (5% ± 6% vs 18% ± 9% vs 17% ± 4%; P < 0.001). Four patients (6%) in the low-risk group and 5 (62%) in the intermediate-risk group showed extensive areas of LGE. All patients except 1 (86%) at highest risk (n = 6) showed extensive areas of LGE.

CONCLUSIONS

LGE extension is concordant with the novel SCD-risk model defining low- and high-risk groups; it may provide additional information, allowing better discrimination to support implantable cardioverter-defibrillator decision. LGE quantification holds promise for SCD stratification in HCM.

Current Role And Future Prospects Of Magnetic Resonance Imaging In The Field Of Atrial Fibrillation Ablation

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice, and catheter ablation of AF has become a first-line treatment for symptomatic drug-refractory AF. However, this is a complex procedure and recurrences after a single ablation procedure are frequent. New technologies are needed to simplify the procedure and improve results, and cardiac magnetic resonance (CMR) has emerged as a useful tool to stratify the risk of recurrence, guide the ablation procedure, and monitor the post-ablation remodeling process. This review summarizes the current role of CMR in the field of AF ablation and offers a perspective on its future potential.

Subclinical Myocardial Disease in Heart Failure Detected by CMR

Noninvasive cardiac imaging plays a central role in the assessment of patients with heart failure at all stages of disease. Moreover, this role can be even more important for individuals with asymptomatic cardiac functional or structural abnormalities-subclinical myocardial disease - because they could have benefits from early interventions before the onset of clinical heart failure. In this sense, cardiac magnetic resonance offers not only precise global cardiac function and cardiac structure, but also more detailed regional function and tissue characterization by recent developing methods. In this section, some of the main methods available for subclinical myocardial disease detection are reviewed in terms of what they can provide and how they can improve heart failure assessment.