MRI of subclinical coronary atherosclerosis

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the Western world. Whereas atherosclerosis alone is rarely fatal, sudden luminal thrombosis precipitates life-threatening clinical events such as acute coronary syndromes and stroke. Plaques assumed to cause luminal thrombosis are referred to as vulnerable plaques, which tend to preserve a normal vessel lumen. Today's clinical assessment of CAD is based on the severity of luminal narrowing or flow restriction and functional indices of cardiac ischemia, thus making a priori detection of vulnerable plaques ambiguous. MRI is an emerging noninvasive imaging modality and is unique in its ability to offer morphologic, functional, and biologic information, including several approaches to detect, quantify, and characterize atherosclerotic plaque burden and composition. These methods, which include noncontrast and contrast-enhanced vessel wall imaging, have shown great promise to assess morphological and biological characteristics of vulnerable plaques, such as inflammatory activity, neovasculature, or positive vessel wall remodeling. Current research that focuses on the development of novel contrast agents for the identification of biologic processes associated with plaque progression and plaque rupture ultimately may facilitate the detection of subclinical disease, enable earlier treatment, and allow imaging-based therapy control.