Infectious endocarditis (IE) is a pathology where the mortality rate of between 20 and 25%, but a higher morbidity since 50% of the patients are treated by a valvular surgical procedure. The diagnosis of IE is often difficult and therefore too late. In 2015, the European Society of Cardiology recommendations published by the integrate Positron Emission Tomography with Computed Tomography (PET/CT) with 18F-Fluorodeoxyglucose (18F-FDG) in the diagnostic management of IE.

However, during conventional examinations, with 12 hours fasting and low carb dieting, myocardial uptake of 18F-FDG may be intense and interfere with results.

The purpose of this study is to assess a strict low carbohydrate diet as Atkins (<3gram/day of carbohydrate) diet to facilitate the infective endocarditis diagnosis by 18F-FDG PET/CT Primary objective is to assess a strict low carbohydrate diet during 12h and 12h fasting for enhancing the contrast between infect area and surrounding structures and improve the detectability of infective endocarditis by PET/CT

Secondary objectives:

1. Comparison of the detection sensitivity of IE outbreaks between 18F-FDG PET/CT performed with the low carbohydrate diet and conventional diet performed
2. To assess the strict low carbohydrate diet effects on the uptake 18F-FDG distribution , particularly in the myocardium, circulating blood, skeletal muscles, brain and liver.
3. Characterization of metabolic changes generated by the low carbohydrate diet using plasma bioassays (blood glucose, insulinemia, free fatty acid concentration, ß-hydroxybutyrate).

Inclusion Criteria:

• Hospitalized patients with certainly infective endocarditis (95%) such Duke and Li criteria
• Patients with a social protection system
• No impossibility of performing (18)F-FDG PET (agitated, confused patient, etc)
• Stable clinically
• Adaptive antibiotic therapy for at least 8 days
• No known allergy to making impossible to follow strict carbohydrate diet

Exclusion Criteria:

• Pregnancy, breastfeeding and woman of childbearing age without effective contraception
• Patients under guardianship or curators.
• No treatment with corticoids, valproate, carbamazepine, phenytoin, phenobarbital, catecholamines
• Unbalanced diabetes (fasting capillary blood glucose > 1,8 g/l ou 10 mmol/l)
• Patients with known hypersensitivity to 18F-FDG or any component of this product