Parametric Mapping Cardiac Magnetic Resonance Imaging for the Diagnosis of Myocarditis in Children in the Era of COVID-19 and MIS-C

Figures

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  Figure 1. T1 mapping demonstrates a global increase in myocardial T1 relaxation times at the base (A), mid-ventricular level (B), and the apex (C). The average left ventricular myocardial T1 relaxation time is prolonged (1067 ms), and myocardial extracellular volume is elevated (32%).

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  Figure 2. T2 mapping demonstrating the regional increase in myocardial T2 relaxation times at the basal anteroseptal and anterolateral segments (A), with normal T2 times at the mid-ventricular level (B) and the apex (C). Clinical vignette: A 20-month-old female with myocarditis associated with rhino/enterovirus, rapid left ventricular ejection fraction recovery from 24% to 48%, elevated troponin, and diffuse low voltage QRS complexes on electrocardiogram. There was no evidence of myocardial delayed enhancement after gadolinium contrast emphasizing the additional utility of T1 and T2 mapping in the evaluation of myocarditis.

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  Figure 3. Late gadolinium enhancement (LGE) imaging allows the noninvasive visualization of areas affected by myocardial scar, conferring clinicians the unique ability to differentiate ischemic from nonischemic lesions based on typical LGE patterns.

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  Figure 4. CMR in an adolescent with acute myocarditis: (A) Shows subepicardial early gadolinium enhancement (EGE) (white arrow); (B) Shows subepicardial LGE (white arrow).

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  Figure 5. T1 mapping demonstrating the global increase in myocardial T1 relaxation times at the base (A), mid-ventricular level (B), and the apex (C). The average left ventricular myocardial T1 relaxation time is mildly prolonged (1077 ms).

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  Figure 6. T2 mapping demonstrating normal myocardial T2 relaxation times at the base (A), mid-ventricular level (B), and at the apex (C). Clinical vignette: 12-year-old female with possible chronic myocarditis associated with Parvovirus B19, dilated LV with decreased LVEF 22%.

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  Figure 7. Several putative mechanisms of myocarditis due to SARS-CoV-2 and other common cardiotropic viruses.

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  Figure 8. LGE in the mid myocardium of the inferior and lateral wall (white arrows). Clinical vignette: 15-year-old-female soccer player with COVID-19-associated myocarditis. This subject reported shortness of breath and chest pain with activity and was found to have ventricular ectopy and non-sustained runs of ventricular tachycardia on Holter monitoring.

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  Figure 9. CMR shows no LGE (A) but diffusely elevated T1 time (B).

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  Figure 10. A 16-year-old-male with mRNA COVID-19 vaccine-associated myocarditis. (A) subepicardial LGE (white arrow); (B) subepicardial LGE (white arrow); (C) early gadolinium enhancement (EGE) (white arrow); and (D) shows enhanced T2 signal (white arrow).