Role of ¹8F-FDG PET/CT in the diagnosis of infective endocarditis in patients with an implanted cardiac device: a prospective study.

PURPOSE: Infective endocarditis (IE) is widely underdiagnosed or diagnosed after a major delay. The diagnosis is currently based on the modified DUKE criteria, where the only validated imaging technique is echocardiography, and remains challenging especially in patients with an implantable cardiac device. The aim of this study was to assess the incremental diagnostic role of (18)F-FDG PET/CT in patients with an implanted cardiac device and suspected IE. METHODS: We prospectively analysed 27 consecutive patients with an implantable device evaluated for suspected device-related IE between January 2011 and June 2013. The diagnostic probability of IE was defined at presentation according to the modified DUKE criteria. PET/CT was performed as soon as possible following the clinical suspicion of IE. Patients then underwent medical or surgical treatment based on the overall clinical evaluation. During follow-up, we considered: lead cultures in patients who underwent extraction, direct inspection and lead cultures in those who underwent surgery, and a clinical/instrumental reevaluation after at least 6 months in patients who received antimicrobial treatment or had an alternative diagnosis and were not treated for IE. After the follow-up period, the diagnosis was systematically reviewed by the multidisciplinary team using the modified DUKE criteria and considering the new findings. RESULTS: Among the ten patients with a positive PET/CT scan, seven received a final diagnosis of "definite IE", one of "possible IE" and two of "IE rejected". Among the 17 patients with a negative PET/CT scan, four were false-negative and received a final diagnosis of definite IE. These patients underwent PET/CT after having started antibiotic therapy (≥48 h) or had a technically suboptimal examination. CONCLUSION: In patients with a cardiac device, PET/CT increases the diagnostic accuracy of the modified Duke criteria for IE, particularly in the subset of patients with possible IE in whom it may help the clinician manage a challenging situation.