We report a case of a 75 year-old man who was diagnosed with a L3-L4 spondylitis with psoas abscess documented at Prevotella denticola. However, the dental origin of the bacteria, the presence of the spondylitis, and the identification on an aneurysm of the inter-atrial septum with a patent oval foramen and finally the metabolic activity of the aortic valve and teeth revealed by 18F-FDG PET/ CT makes the diagnostic of endocarditis questionable. The input of the 18F-FDG PET/ CT on the diagnosis of native valve infectious endocarditis would be valuable in these clinical situations but needed more studies.