Myocarditis associated with immune-checkpoint inhibitors diagnosed by cardiac magnetic resonance imaging.

Myocarditis associated with immune-checkpoint inhibitors (ICIs) is a rare, but critical adverse event. Although endomyocardial biopsy (EMB) is the standard for diagnosis of myocarditis, there is a possibility of false negatives due to sampling errors and local nonavailability of EMB, which may hamper the appropriate diagnosis of myocarditis. Therefore, an alternative criterion based on cardiac magnetic resonance imaging (CMRI) combined with clinical presentation has been proposed, but not emphasized sufficiently. We report a case of myocarditis after ICIs administration, which was diagnosed using CMRI in a 48-year-old male with lung adenocarcinoma. CMRI provides an opportunity to diagnose myocarditis during cancer treatment.