Abstract: The invention provides reagents and methods for their use in in vivo diagnosis of atherosclerosis. In particular, the invention provides monoclonal antibodies which bind oxidation specific epitopes in atherosclerotic plaque lesions, such as those which occur in oxidized LDL, in vivo with high binding specificity; i.e., at about 10 to 20 times the rate of binding of the antibodies to adjacent normal arterial tissue. When detectably labeled and administered according to the invention, the antibodies are clearly imaged when bound to atherosclerotic plaque using known imaging techniques and devices, such as a gamma camera. In addition, the invention provides a method for substantially reducing interference from background signal in the blood pool into which such agents are introduced for detection and quantification of atherosclerotic plaque burden in the cardiovascular tissue of a host.