Fig. 1.

Acute myocarditis 4 days after Spikevax (Moderna) vaccine administration in a 29-year-old patient (images refer to patient n. 19 from Table 1) presenting with infarct-like symptoms of acute chest pain, with ECG ST-elevation changes and troponin rise. End-systolic and end-diastolic cine-SSFP frames (a and b) show a non-dilated and functionally preserved left ventricular cavity (EF 61%; LVEDVI: 76.8 mL/m²). Typical CMR hallmarks of an acute myocarditis can be observed in “edema-weighted” T2w-STIR short axis plane (c), consisting of the presence of a non-ischemic epicardial stria of high signal intensity involving the anterior- and infero-lateral mid-basal wall (arrows) and closely matching with LGE findings (d) (mid-ventricular level shown). Acute inflammation was also confirmed at myocardial mapping images showing focally increased native T1 mapping (1090 ms of a ROI on the middle-apical lateral wall; n.v. 950–1000 ms; e) and T2 mapping values (avg. 55 ms; n.v. < 50 ms; f) (AHA segments T2 mapping values shown in g). The patient’s clinical course was benign and uneventful at 25 days follow-up