There is an increasing body of evidence that a dynamic inflammatory process plays a role in the initiation, progression and destabilization of atherosclerotic plaques. The biological composition and inflammatory state of an atherosclerotic plaque, rather than the degree of stenosis or its size, are the major determinants of life-threatening events, such as ischemic cerebrovascular accident and acute coronary syndrome. To date, there is no non-invasive method clinically available for visualizing inflammation of individual plaques. Recently, we and others have shown that 18(F)-fluorodeoxyglucose (FDG) uptake, namely inflammation, can be evaluated quantitatively in the aortic, carotid, iliac and femoral plaques by using FDG positron emission tomography (PET) co-registered with computed tomography (FDG-PET/CT). Therefore, FDG-PET/CT, a combined functional and structural wholebody imaging modalities, holds great promise for non-invasive evaluation of inflammation - namely, activity - of atherosclerotic plaques of large arteries.