CT Imaging of the Vulnerable Plaque

Acute coronary syndromes are most often the result of vulnerable atherosclerotic plaque events. Plaques events occur when intimal fibroatheroma in the coronary artery wall becomes vulnerable to erosion or rupture. Such vulnerable plaques can be distinguished from quiescent atheroma by features that have been defined through histopathology and invasive imaging. A challenge for coronary CT angiography has been to identify vulnerable plaques non-invasively. Were this possible, CT angiography could offer comprehensive vessel assessment including stenosis severity and plaque characteristics with the hope of reducing acute coronary events through timely intervention. Over the past decade, advances in invasive imaging techniques have enabled unstable coronary plaques to be accessed more readily. In this fashion it has been possible to correlate invasive appearances to CT angiographic findings in an unprecedented manner. Several CT defined plaque characteristic have now been described to reliably identify unstable plaques. Retrospective studies have demonstrated the utility of these plaque features to predict future acute coronary events. If these can be confirmed in prospective studies, the intrinsic benefits of non-invasive imaging will position coronary CT angiography firmly in our armamentarium to image coronary arteries and help prevent acute coronary events.