Cardiovascular Magnetic Resonance in MINOCA and Acute Myocarditis: A Comparative Multiparametric Evaluation.

Myocardial infarction with non-obstructive coronary arteries (MINOCA) and acute myocarditis (AM) often present with overlapping clinical features and biomarker profiles, making early differential diagnosis challenging. Cardiovascular magnetic resonance (CMR) is the reference modality for etiological assessment through functional evaluation and multiparametric tissue characterization. The aim of this study was to compare clinical and CMR characteristics of patients with MINOCA and suspected AM, and to identify imaging features enabling accurate differentiation. We retrospectively analyzed 127 consecutive patients undergoing CMR (February 2021-October 2024): 62 with suspected MINOCA and 65 with suspected AM. Clinical data, laboratory findings, ECG, and CMR parameters (cine imaging, T1/T2 mapping, extracellular volume [ECV], and late gadolinium enhancement [LGE]) were assessed. MINOCA patients were older (median 59 years) and predominantly female (64.5%), whereas AM patients were younger (median 29 years) and mainly male (81.5%). AM was associated with higher troponin and inflammatory markers. Among patients initially referred with suspected MINOCA, LGE was present in 50.0%, compared with 93.8% of those referred with suspected acute myocarditis (p < 0.001). MINOCA showed predominantly ischemic LGE patterns, while AM exhibited non-ischemic subepicardial or mid-wall LGE with myocardial edema. CMR confirmed myocardial infarction in 48.4% of patients and identified alternative diagnoses in 41.9%, while 9.7% had normal CMR findings. Multiparametric CMR reliably distinguishes ischemic from inflammatory myocardial injury in patients with chest pain, elevated troponin, and non-obstructive coronaries. Early CMR integration improves diagnostic accuracy and supports tailored management.