Helical CT finding of an acute myocardial infarction in a patient with unstable angina

A 58-year-old-man with unstable angina developed a violent retrosternal and interscapular pain during coronary angiography with no associated ECG abnormalities. The patient was immediately submitted to transesophageal echocardiography, which revealed an echo-free space behind the ascending aorta thought to be consistent with an aortic dissection. To confirm this finding the patient underwent contrast-enhanced helical CT, which ruled out a dissection but revealed a small hypoattenuating, ill-defined area within the lateral wall of the left ventricle, consistent with an acute myocardial infarction. The finding was first confirmed by bedside echocardiography and later validated by laboratory tests. Review of the left coronary angiogram showed the culprit lesion at the origin of a major acute marginal branch of the circumflex artery.