Identification of unstable coronary atherosclerotic plaques.

The mechanisms of atherogenesis are better understood and the detection of atherosclerosis has improved with the different diagnostic methods currentl y available. However, it is almost impossible at present to differentiate h igh risk, unstable or vulnerable plaques from quiescent or stable plaques o f atherosclerosis. This is a crucial problem given the banality of atherosc lerosis on the one hand and,, on the other hand, the serious consequences ( acute coronary syndromes, cerebrovascular accidents) of thrombotic occlusio n at the site of an atherosclerotic plaque. It has now been established that the composition of the plaque is more impo rtant than the degree of stenosis, a fundamental concept in the risk of pla que rupture, precipitating the cascade of reactions leading to uncontrolled thrombosis. Consequently, new imaging techniques should address the proble m of analysing the composition of atheromatous plaques. Endovascular ultras onography, fast CT, angioscopy, nuclear imaging techniques and MRI are so m any promising tools. However, non-invasive techniques should be distinguish ed from invasive ones. In all prbability, it will be the former which will turn out to be the most useful diagnostic aid in pauci or asymptomatic pati ents. This article reviews the different imaging techniques under evaluation for the identification of risk of plaque rupture.