ORIGINAL ARTICLE Role of 18 F-FDG PET/CT in the diagnosis of infective endocarditis in patients with an implanted cardiac device: a prospective study Maddalena Graziosi & Cristina Nanni & Massimiliano Lorenzini & Igor Diemberger & Rachele Bonfiglioli & Ferdinando Pasquale & Matteo Ziacchi & Mauro Biffi & Cristian Martignani & Michele Bartoletti & Fabio Tumietto & Giuseppe Boriani & Pier Luigi Viale & Stefano Fanti & Claudio Rapezzi Received: 27 December 2013 /Accepted: 28 March 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract 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 validat- ed imaging technique is echocardiography, and remains chal- lenging 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 im- planted 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 diag- nostic 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. Pa- tients then underwent medical or surgical treatment based on the overall clinical evaluation. During follow-up, we consid- ered: 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 in- creases 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. Keywords Infective endocarditis . Pacemaker . Implantable cardioverter defibrillator . Positron emission tomography Introduction The diagnosis of infective endocarditis (IE) in patients with cardiac leads is still challenging [1]. The reported prevalence of cardiac device infection is up to 0.8 % for implantable cardioverter defibrillators (ICD) and ranges from 0.13 to 19.9 % for pacemakers (PM) [2, 3]. Distinguishing whether the infection is limited to the device pocket or extends to the intravascular portion of the leads and/or cardiac valve leaflets can be extremely difficult [4]. The diagnosis of IE is currently based on the modified DUKE criteria [5, 6], where the only considered imaging technique, which is often inconclusive, is echocardiography [6–8]. Indeed, even transoesophageal echo- cardiography (TEE) in this context is often suboptimal and is limited by a series of elements including: lead echoes and M. Graziosi : M. Lorenzini : I. Diemberger : F. Pasquale : M. Ziacchi : M. Biffi : C. Martignani : G. Boriani : C. Rapezzi (*) Cardiology Unit, Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna, Italy e-mail: claudio.rapezzi@unibo.it C. Nanni : R. Bonfiglioli : S. Fanti Nuclear Medicine Unit, Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Bologna, Italy M. Bartoletti : F. Tumietto : P. L. Viale Infectious Diseases Unit, Department of Medical and Surgical Sciences, Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Bologna, Italy Eur J Nucl Med Mol Imaging DOI 10.1007/s00259-014-2773-z