Molecular imaging of vulnerable atherosclerotic plaques.

Despite primary and secondary prevention, serious cardiovascular events such as unstable angina or myocardial infarction still account for a third of all deaths worldwide. Therefore, identifying individual patients with vulnerable plaques at high risk for plaque rupture is a central challenge in clinical medicine. Several noninvasive techniques, such as magnetic resonance imaging, multislice computed tomography and electron beam tomography are currently being tested for their ability to identify such patients by morphological criteria. In contrast, noninvasive scintigraphic techniques use radiolabeled molecules to detect functional aspects in atherosclerotic plaques by visualizing its biologic activity. Based upon knowledge regarding the pathophysiology of atherosclerosis, various studies - in vitro, in vivo and first clinical trials - have used different tracers for plaque imaging studies, including radioactive labeled lipoproteins, components of the coagulation system, cytokines, mediators of the metalloproteinase system, cell adhesion receptors and even whole cells.