Coronary angiography after a myocardial infarction sometimes do not show significant obstructive lesions, more so in females. Reynolds HR and colleagues evaluated the mechanism of myocardial infarction in women without angiographically demonstrable obstructive coronary artery disease [Mechanisms of Myocardial Infarction in Women Without Angiographically Obstructive Coronary Artery Disease. Circulation. 2011; 124: 1414-1425]. They excluded patients with angiographic coronary stenosis of fifty percent or more as well as those who were using vasospastic agents. Intravascular ultrasound (IVUS) and cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) was done in addition to coronary angiography in the diagnostic workup of these patients. Plaque rupture was noted in thirty eight percent of the patients who underwent IVUS. Abnormal CMR findings were noted in about sixty percent of those who underwent CMR. Of these twenty six, seventeen had LGE and additional nine had T2 signal hyperintensity indicating edema. Though the most common LGE pattern was transmural/subendocardial, indicating ischemia, some had mid myocardial / subepicardial nonischemic patterns. T2 signal hyperintensity was commonly associated with plaque disruption while LGE was not. Authors propose that vasospasm and embolism could be the possible mechanisms of ischemic LGE in those without plaque disruption. They also suggest that CMR and IVUS good tools to provide mechanistic insight into female patients with myocardial infarction and non obstructive coronaries on angiography.