ABSTRACT
This chapter focuses on lipid-based contrast agents that have high longitudinal relaxivities and on iron oxide materials with highly effective transverse relaxivities. Although the causes of atherosclerosis are completely understood, most atherosclerotic lesions are characterized by a thickening of the arterial intima and are typically composed of a lipid core and an overlying fibrous cap. X-ray angiography remains the gold standard for diagnosis and quantification of atherosclerotic plaques. The small size of the vessels and adjacent lumen requires the acquisition of high spatial and contrast resolutions for atherosclerosis imaging. A wide variety of lipid aggregate geometries occur, of which micelles, liposomes, and microemulsions are among the most relevant for MR-based contrast agents. Additionally, targeted mixed micelles were recently developed for active targeting of functional macrophages in atherosclerotic plaque. The development of molecular MRI of atherosclerosis will clearly help to detect and follow the changes in atherosclerotic plaque composition in vivo and, hopefully, identify the most relevant markers of plaque instability.
