Background: Poor oral health has long been associated with the development of systemic disease. The risk of infective endocarditis (IE) after dental procedures is a typical example. However, the literature is conflicting about the causal relationship between oral bacterial pathogens and risk of IE. [18F]FDG PET/CT has proven to be a useful diagnostic tool in patients with suspected IE. This study focused on: 1) the correlation between increased glucose metabolism on [18F]FDG PET/CT scans, recent dental treatment, and inflammation and/or infection sites in the oral cavity reported by the dentist; and 2) a possible correlation between IE and oral health status based on (extra)cardiac findings on [18F]FDG PET/CT scans.
Methods: This retrospective study included 52 patients (32 men, 20 women; median age, 58 years; IQR [44-66] years). A total of 19 patients were diagnosed with IE (group 1), 14 patients with possible IE (group 2), and 19 patients were not diagnosed with IE based on the modified Duke criteria (group 3). Patient characteristics and dental records were reviewed for relevant clinical data at the time the [18F]FDG PET/CT scan was performed. All [18F]FDG PET/CT scans were examined visually by pattern recognition using a three-point scale, and semi-quantified within the volume of interest (VOI) using SUVmax. The Fisher’s exact probability test and Pearson’s correlation were used to analyze the relationship between dental oral cavity findings and [18F]FDG PET/CT scans. A one-way ANOVA was conducted to compare the SUVmax measured in the oral cavity. To analyze the differences among visual [18F]FDG uptake scores in groups 1, 2, and 3, the Kruskal-Wallis H test was used.
Results: No correlation was found between visual [18F]FDG uptake scores and SUVmax as a marker of [18F]FDG uptake and possible sites of oral inflammation and infection, or dental treatments based on the dental records of 52 patients. Between groups 1, 2, and 3, the visual [18F]FDG uptake scores (H(2) = 4.359, p = .113) and SUVmax (F(2, 69) = 0.27, p = .798) were not significantly different. A significant difference in SUVmax of the valve for the three groups (F(2, 309) = 28.06, p < .001) was observed.
Conclusions: The results of this retrospective study suggest that no correlation exists between [18F]FDG PET/CT uptake in the oral cavity and dental treatments or inflammation/infection reported by the dentist. Furthermore, no correlation between IE and actual oral health status was demonstrated. This study revealed no causal relationship between oral pathogens and risk of IE. Additional research is needed to conclude whether [18F]FDG PET/CT imaging is a reliable diagnostic modality for oral inflammation and infection sites.