PET measurement of periodontal FDG uptake correlates with histological measurement of carotid plaque inflammation

Objectives Several lines of evidence establish periodontal disease as an important risk factor for atherosclerosis. 18F-FDG-PET imaging is an established method for measuring metabolic activity in human tissues and blood vessels. Here we use FDG-PET imaging to test the hypothesis that metabolic activity within periodontal tissue (a possible surrogate for periodontal inflammation) predicts inflammation in a remote atherosclerotic vessel.

Methods 18 patients with carotid artery stenosis, who were scheduled for carotid endarterectomy (CEA) underwent FDG-PET imaging 3 hours after ¹⁸F-FDG administration (13-25mCi). Periodontal FDG uptake was measured by obtaining standardized uptake values (SUVs) from the upper and lower gumlines of each patient, and the ratio of periodontal to background (blood) activity was determined (TBR). Localization of carotid and periodontal activity was facilitated by PET co-registration with CT images. Less than one month after PET imaging, subjects underwent CEA, during which the atherosclerotic plaques were removed and subsequently stained with anti-CD68 antibodies to quantify macrophage infiltration. Periodontal FDG uptake was compared with plaque macrophage infiltration for each patient.

Results Periodontal TBR correlated with carotid artery TBR (R=0.68, p<0.01) and with histologically-assessed inflammation within the excised carotid plaques for each patient (R=0.60, p<0.01).

Conclusions FDG-PET measurements of metabolic activity within periodontal tissue correlate with and may be predictive of macrophage infiltration within carotid plaques. These findings further support an association between periodontal and atherosclerotic diseases.