Contrast enhanced cardiac magnetic resonance (CMR) imaging is considered to be the gold standard for assessment of coronary microvascular obstruction. Magnetic resonance imaging of the heart is obtained ten to fifteen minutes after injecting a gadolinium-based contrast at a dose of 0.1 mmol/kg. Infarcted tissue is seen as a region of hyper enhancement. A dark core of hypoenhancement within the infarct tissue is taken as a region of coronary microvascular obstruction [McGeoch R et al.The index of microcirculatory resistance measured acutely predicts the extent and severity of myocardial infarction in patients with ST-segment elevation myocardial infarction. JACC Cardiovasc Interv. 2010 Jul;3:715-22].