Cardiac Magnetic Resonance in MINOCA: From Diagnosis to Phenotyping

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a working diagnosis established after coronary angiography and requires further evaluation to distinguish true ischemic MINOCA from alternative non-ischemic diagnoses. Accurate identification of the underlying etiology is essential because prognosis and management vary substantially among disease entities. Cardiac magnetic resonance (CMR) has emerged as the central noninvasive imaging modality in the diagnostic evaluation of MINOCA. This review summarizes the role of CMR in patients presenting with MINOCA, focusing on diagnostic pathways, tissue characterization techniques, phenotypic classification, prognostic assessment, clinical practice, and emerging technologies. CMR enables comprehensive assessment of ventricular function, myocardial edema, fibrosis, necrosis, and microvascular injury through cine imaging, T1- and T2-based tissue characterization, and late gadolinium enhancement. By integrating these findings, CMR differentiates patients with true ischemic MINOCA from those with alternative non-ischemic diagnoses, thereby guiding subsequent investigations and management. Early CMR substantially increases diagnostic yield and frequently identifies a specific etiology that directly influences treatment decisions. Beyond diagnosis, CMR provides important prognostic information through the quantification of infarct size, microvascular obstruction, myocardial edema, and scar burden. Advanced parametric mapping techniques and artificial intelligence–assisted image analysis may further refine disease phenotyping and improve risk stratification.

Keywords: Acute coronary syndrome, cardiac magnetic resonance, MINOCA, myocarditis.