Clinical feasibility of molecular imaging of plaque inflammation in atherosclerosis.

Despite substantial advances in the diagnosis and management of coronary artery disease, acute coronary events continue to occur in many patients. It has been increasingly realized that the lesions responsible for acute events may not necessarily be critically obstructive and hence not be associated with inducible ischemia. Various morphologic features of plaque vulnerability have been described by CT angiography, intravascular ultrasound, and optical coherence tomography. The culprit plaques often demonstrate large plaque and necrotic core volumes, positive vascular remodeling, and attenuation of fibrous plaque caps. The remaining obligatory component of plaque vulnerability is fibrous cap inflammation; molecular imaging is best suited for identification of monocyte-macrophage infiltration. Whereas multiple candidate targets have been evaluated in preclinical molecular imaging studies, only (18)F-FDG and (99m)Tc-annexin-A5 have been recently used in the settings of acute vascular events. These 2 imaging strategies have demonstrated the clinical feasibility of imaging for detection of inflammation.