Role of cardiac MRI in the diagnosis of immune checkpoint inhibitor‐associated myocarditis

Abstract Immune checkpoint inhibitor (ICI)‐induced cardiotoxicity is a rare immune‐related adverse event (irAE) characterized by a high mortality rate. From a pathological point of view, this condition can result from a series of causes, including binding of ICIs to target molecules on nonlymphocytic cells, cross‐reaction of T lymphocytes against tumor antigens with off‐target tissues, generation of autoantibodies and production of proinflammatory cytokines. The diagnosis of ICI‐induced cardiotoxicity can be challenging, and cardiac magnetic resonance (CMR) represents the diagnostic tool of choice in clinically stable patients with suspected myocarditis. CMR is gaining a central role in diagnosis and monitoring of cardiovascular damage in cancer patients, and it is entering international cardiology and oncology guidelines. In this narrative review, we summarized the clinical aspects of ICI‐associated myocarditis, highlighting its radiological aspects and proposing a novel algorithm for the use of CMR.