Abstract
Myocardial infarction with nonobstructive coronary artery (MINOCA) is a common condition in clinical practice with multiple specific causes, such as plaque rupture, plaque erosion, and epicardial coronary vasospasm. There must be an ischemic mechanism responsible for the myocyte injury and an exclusion of nonischemic mechanisms that can mimic myocardial infarction, and then a diagnosis of MINOCA can be made. Cardiac magnetic resonance (CMR) plays an essential role in the diagnosis and differential diagnosis of MINOCA, which cannot only exclude myocarditis, Takotsubo syndrome, and cardiomyopathies, but also provide imaging confirmation of acute myocardial infarction. In this study, we presented 2 typical cases with the clinical presentation of acute myocardial infarction but normal or nonobstructive epicardial coronary arteries. Further CMR examinations showed different patterns of late gadolinium enhancement (LGE) in these 2 cases, one case with subendocardial LGE of the anterolateral wall and the other one with subepicardial LGE of the lateral wall, which indicated 2 different mechanisms for the myocyte injury. Subsequently, these 2 patients received different treatment regimens and were discharged with improved symptoms. In conclusion, CMR should be a mandatory test in patients with suspected MINOCA, because it can not only make a clear diagnosis, but also play an important role in guiding clinical decision-making.