Other Imaging Modalities in Infective Endocarditis Diagnosis

The recent development of hybrid molecular imaging equipment for both conventional nuclear medicine (e.g., SPECT/CT) and PET (e.g., PET/CT) has raised evidence of the impact of SPECT and PET performed with suitable infection imaging agents and co-registered with CT in the diagnosis of IE. Their unique whole-body exploring ability, i.e., to detect multiple sites of disease with a single examination, has been proven effective in guiding clinical management of patients in view of the selection of optimal treatment strategy. Radiolabeled leukocytes scintigraphy and [18F]FDG-PET/CT have been recently included in the 2015 Guideline for the management of infective endocarditis and proposed as diagnostic tools in the diagnostic flow chart of IE. In particular, molecular imaging techniques have been proposed to confirm/exclude IE in case of “possible” or “rejected” IE (as for FUO), and to assess the embolic burden in case of “definite” IE. The main added value of using these techniques are the reduction of the rate of misdiagnosed IE, classified in the ‘Possible IE’ category by using the Duke criteria alone and the detection of peripheral embolic and metastatic infectious events. Evidence is higher in case of and prosthetic valve IE (PVE), however, data show increased accuracy also in presence of native IE (NVE) and unconclusive clinical findings. This new approach to IE patient where imaging techniques including nuclear imaging are getting more and more important is based on the concept that IE is not a single disease but, rather, may present with very different aspects, depending on the first organ involved, the underlying cardiac disease (if any), the microorganism involved, the presence or absence of complications, and the patient’s characteristics. Therefore, a very high level of expertise is needed, coming from practitioners from several specialties, including microbiologists, imagers, clinicians and surgeon. Including all these specialists into the patients’ management is fundamental.