Figure 1.

Example of a metastatic malignant melanoma patient under nivolumab treatment in whom checkpoint inhibitor-related myocarditis was verified by ¹⁸F-FDG PET/MR in our institution. Clockwise from upper-left: Late-phase MR, maximum-intensity-projection PET images from three different angles (anterior, posterior, left-posterior view), axial fusion PET/MR, axial PET. Hybrid imaging showed a hypertrophied normal-sized left ventricle with normal left ventricular ejection fraction and with circumscribed left-ventricular midmyocardial late gadolinium enhancement (infero-latero-basally, white arrow in upper-left image), mild edema, and increased ¹⁸F-FDG accumulation (black/white arrows in PET image) which was indicative of active myocarditis.