Finally, in an attempt to improve the detection of vulnerable lesions, contrast agents for CT imaging of macrophage-rich atherosclerotic plaques have been developed and tested in the major mouse models of atherosclerosis, for example liposomal-iodine [254] or PEGylated gold nanoparticles [255] in ApoE−/− mice and, more recently, gold particles of 15 nm with a polyethylene glycol coating called Aurovist in the ApoE−/−C1039G+/− model [43]. The gene discussed is APOE; the disease is atherosclerosis.