This review examines the pathophysiological processes affecting the Extracellular Volume (ECV) in both the acute and chronic phases of myocardial infarction. It discusses how the constellation of acute myocardial injuries leads to ECV expansion, establishing it as a robust and independent predictor of adverse left ventricular remodeling, major adverse cardiovascular events, and arrhythmic risk. The review outlines current methodologies for ECV assessment. It is shown that despite limitations related to its non-specific nature and the need for protocol standardization, ECV mapping surpasses traditional approaches in infarct size quantification and risk stratification, paving the way for personalized monitoring of treatment efficacy. The review encompasses foundational validation studies as well as recent research focused on the pathophysiological rationale of the method, technical aspects of its implementation, and clinical applications of ECV analysis, including its role in evaluating anti-remodeling therapies.