Myocardial infarction with non-obstructive coronary arteries represents a heterogeneous subset of acute coronary syndromes characterized by clinical evidence of myocardial infarction in the absence of significant epicardial coronary obstruction. This entity accounts for approximately 5–15% of acute myocardial infarction cases and is more frequently observed in women and younger patients. Its diverse etiologies, including coronary vasospasm, microvascular dysfunction, thromboembolism, and transient occlusion with spontaneous reperfusion, create substantial diagnostic complexity. Moreover, its clinical presentation often overlaps with that of acute myocarditis, as both conditions may manifest with chest pain, elevated cardiac biomarkers, and electrocardiographic abnormalities. Conventional diagnostic tools, including coronary angiography and biomarker assessment, are frequently insufficient to establish a definitive etiological diagnosis. Cardiac magnetic resonance has emerged as a pivotal non-invasive modality for differentiating ischemic from inflammatory myocardial injury. Through multiparametric tissue characterization using T1 and T2 mapping and late gadolinium enhancement patterns, cardiac magnetic resonance enables identification of subendocardial or transmural enhancement consistent with ischemic injury, as well as subepicardial or mid-myocardial enhancement typical of myocarditis. Early implementation of cardiac magnetic resonance following coronary angiography significantly enhances diagnostic accuracy, facilitates appropriate therapeutic selection, and improves prognostic stratification based on the extent of myocardial involvement. Despite limitations related to accessibility and cost, cardiac magnetic resonance plays a central role in the integrated diagnostic algorithm for patients presenting with myocardial injury and non-obstructive coronary arteries. Its use supports precise etiological classification and contributes to more individualized and evidence-based clinical management.