The prevalence of inflammation in carotid atherosclerosis: analysis with fluorodeoxyglucose–positron emission tomography

Aims There is increasing evidence that 18F-fluorodeoxyglucose (FDG)–positron emission tomography (PET) imaging can be useful for non-invasive measurement of atherosclerotic plaque inflammation in humans. However, it is unknown how often atherosclerosis has inflammation in humans. Thus, we examined the prevalence of inflammation in documented carotid atherosclerosis using FDG–PET imaging. Methods and results FDG–PET imaging was performed in 100 consecutive patients who underwent carotid artery ultrasonography (CA-US) for screening of carotid atherosclerosis. Carotid atherosclerosis was considered when patients had the plaque score ≥5 and/or the focal thickening of the maximum intima-media complex ≥2 mm (localized plaque) by CA-US. The inflammation of carotid atherosclerosis was quantified by measuring the standardized uptake value (SUV) of FDG of the carotid artery. Inflammation was defined as present if the SUV score was ≥1.60 (≥1×standard deviation above the average). FDG–PET imaging revealed inflammation in 12 of 41 (29%) patients having carotid atherosclerosis, whereas in 6 of 59 (10%) patients not having carotid atherosclerosis ( P < 0.01). In patients with documented atherosclerosis by CA-US, body mass index, waist circumference, and the number of localized plaques were greater in a subset with inflammation than in a subset without. Conclusion Inflammation was visualized by FDG–PET imaging in ∼30% of patients with documented carotid atherosclerosis.