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.

Imaging of children with COVID-19: experience from a tertiary children's hospital in the United States.

BACKGROUND: Imaging of novel coronavirus disease 2019 (COVID-19) has been described in adults, but children have milder forms of disease. Pediatric imaging descriptions are of asymptomatic children, raising the question of whether imaging is needed in this patient group. OBJECTIVE: To describe the utilization and imaging findings in children with COVID-19 along with the comorbidities, treatment and short-term outcomes. MATERIALS AND METHODS: We retrospectively reviewed pediatric patients who had a confirmed positive test for COVID-19 during a 2-month period. We noted symptoms and presence of imaging at presentation. Comorbidities were recorded for children with imaging. Children were categorized as having multisystem inflammatory syndrome in children (MIS-C) if they met criteria for the disorder. For children who were admitted to the hospital, we documented length of hospital stay, need for intensive care unit care/ventilator support, and treatment regimen. We evaluated all imaging for acute/chronic abnormalities including chest radiographs for interstitial or alveolar opacities, distribution/symmetry of disease, zonal predominance, and pleural abnormalities. We performed descriptive statistics and compared children with MIS-C with the cohort using a Fisher exact test. RESULTS: During the study period, 5,969 children were tested for COVID-19, with 313 (5%) testing positive. Of these, 92/313 (29%) were asymptomatic and 55/313 (18%) had imaging and were admitted to the hospital for treatment. Forty-one of 55 patients (75%) with imaging had comorbidities. Chest radiographs were the most common examination (51/55 patients, or 93%) with most demonstrating no abnormality (34/51, or 67%). Children with MIS-C were more likely to have interstitial opacities and pleural effusions. US, CT or MRI was performed in 23/55 (42%) children, 9 of whom had MIS-C. Only one chest CT was performed. CONCLUSION: In our study, most pediatric patients with COVID-19 did not require hospital admission or imaging. Most children with imaging had comorbidities but children with MIS-C were more likely to have no comorbidities. Children with imaging mostly had normal chest radiography. Advanced imaging (US, CT, MRI) was less common for the care of these children, particularly CT examination of the chest and for children without MIS-C.