Abstract
According to the 2025 recommendations of the European Society of Cardiology (ESC) and the 2024 consensus statement of the American College of Cardiology (ACC), multimodality imaging has become the cornerstone in the diagnosis of myocarditis, with cardiovascular magnetic resonance (CMR) playing a pivotal role. In patients with low or intermediate clinical risk, a definitive diagnosis of acute myocarditis can be established by CMR using the revised Lake Louise criteria. Endomyocardial biopsy is indicated in patients with high-risk myocarditis and may be considered in those at intermediate risk when biopsy results are likely to alter therapeutic strategy. This article aims to review the definitive diagnostic criteria and to highlight the role of CMR in risk stratification and prognostic assessment in patients with acute myocarditis.