The purpose of this study is to assess the impact of 18-FDG positron emission tomography (PET)/computed tomography (CT) imaging in the management of patients with suspected or proven IE in detecting cardiac valve damages and other extracardiac complications. The study will evaluate whether this procedure can change the clinical decisions (treatments, valve surgery, patients' overall care) and modify the diagnosis of IE.

Introduction:

Infective endocarditis (IE) is a rare disease, often difficult to diagnose with a high mortality rate. Extra-cardiac manifestations, which can occur in 30 to 80% of cases, impact the outcome of the disease. Identifying these manifestations may help confirm an uncertain diagnosis and optimize patients' management.

18-FDG PET/CT imaging, widely used for cancer staging, may also detect hyper-metabolic areas related to extracardiac infectious complications of IE. It provides the opportunity to detect all extracardiac IE infectious complications through a single examination. The impact of 18-FDG PET/CT imaging on the management of IE has yet to be completely evaluated.

Hypothesis:

18-FDG PET/CT implementation could result in both shortening of the initial diagnostic work-up of IE and therapeutic optimization.

Primary objective:

To evaluate the impact of 18-FDG PET/CT on patients' management, as measured by changes in IE therapeutic plans.

Secondary objectives:

• To evaluate the impact of 18-FDG PET/CT on the Duke-Li criteria for IE diagnosis
• To evaluate the performance of 18-FDG PET/CT in detecting valve damages and extracardiac complications induced by the IE
• To evaluate whether 18-FDG PET/CT may help identify the infection's portal of entry
• To evaluate whether the detection of extracardiac complications by FDG PET/CT is associated with the 6-months survival rate
• To identify clinical and biological determinants of extracardiac IE localizations and prognosis
• To determine the inter-reader interpretation of the18-FDG PET/CT results and the reproducibility in preparation and acquisition method

Inclusion Criteria:

1. Subjects aged ≥ 18 years
2. Presenting IE "Duke-Li definite - Duke-Li possible" or strong suspicion of IE "Duke-Li not definite or possible, with initiation of IE antibiotic therapy".
3. Transthoracic or transesophageal ultrasound performed.
4. A stable clinical condition which does not require immediate surgery or contraindicate patient mobilization
5. Absence of cardiac surgery for the current IE episode
6. Covered by the French health insurance system
7. Having given and signed the written study informed consent to the study.

Exclusion Criteria:

1. Patient having already had a 18-FDG PET/CT in the current episode
2. Contraindication to perform a 18-FDG PET/CT
3. Early prosthetic valve IE (cardiac surgery within last 2 months)
4. Inability to understand the information form
5. Pregnant or lactating woman.
6. Cardiac surgery between inclusion and 18-FDG PET/CT
7. Participation to any clinical trial including 18-FDG PET/CT