Binding of [(11)C]PBR28 in atherosclerotic lesions, aortic arch and its branches will be compared with the binding in the contralateral carotid artery and those in healthy subjects. Binding of [(11)C]PBR28 will also be compared with accumulation of [18 F]FDG in each region. In addition, if the patients with atherosclerosis have endarterectomy, the binding in the atherosclerotic lesions will be compared with immunohistological staining of macrophage markers.