Urgent requests for contrast computed tomographic scans of the thorax are often performed for suspected aortic dissections and pulmonary embolisms, both of which have clinical features similar to those seen in acute myocardial infarction. We present two cases with computed tomographic scans showing decreased myocardial enhancement, suggestive of acute myocardial infarction, but no evidence of aortic dissection. Acute myocardial infarction was subsequently confirmed by coronary angiography.