Positron Emission Tomography Measurement of Periodontal 18F-Fluorodeoxyglucose Uptake Is Associated With Histologically Determined Carotid Plaque Inflammation
Study Questions:
Is metabolic activity within periodontal tissue (a possible surrogate for periodontal inflammation) predictive of inflammation in a remote atherosclerotic vessel?
Methods:
A total of 112 patients underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging 92 ± 5 minutes after FDG administration (13-25 mCi). Periodontal FDG uptake was measured by obtaining standardized uptake values from the periodontal tissue of each patient, and the ratio of periodontal to background (blood) activity was determined (target-to-background ratio [TBR]). Standardized uptake value measurements were obtained in the carotid and aorta as well as in a venous structure. Localization of periodontal, carotid, and aortic activity was facilitated by PET co-registration with computed tomography or magnetic resonance imaging. A subset of 16 patients underwent carotid endarterectomy within 1 month of PET imaging, during which atherosclerotic plaques were removed and subsequently stained with anti-CD68 antibodies to quantify macrophage infiltration. Periodontal FDG uptake was compared with carotid plaque macrophage infiltration.
Results:
Periodontal FDG uptake (TBR) is associated with carotid TBR (R = 0.64, p < 0.0001), as well as aortic TBR (R = 0.38; p = 0.029). This association remained significant after adjusting for age, sex, low-density lipoprotein cholesterol, history of hypertension, statin therapy, and diabetes (R = 0.56, p < 0.0001), as well as blood glucose concentration and tracer circulation time (R = 0.78, p < 0.0001). Moreover, a strong relationship was observed between periodontal TBR and histologically assessed inflammation within excised carotid artery plaques (R = 0.81, p < 0.001).
Conclusions:
FDG-PET measurements of metabolic activity within periodontal tissue correlate with macrophage infiltration within carotid plaques. These findings provide direct evidence for an association between periodontal disease and atherosclerotic inflammation.
Perspective:
There is a considerable amount of evidence connecting abnormal gingival health and coronary and carotid disease as well as cardiovascular events. Whether there is a cause-effect or contribution of periodontal disease to plaque inflammation and effect of treatment has been difficult to establish. This technology provides an opportunity to test several hypotheses.
Keywords: Lipoproteins, LDL, Inflammation, Fluorodeoxyglucose F18, Plaque, Atherosclerotic, Periodontal Diseases, Antigens, CD, Tomography, X-Ray Computed, Endarterectomy, Carotid, Carotid Stenosis, Magnetic Resonance Imaging, Positron-Emission Tomography
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