New semiquantitative parameters in digital [F]FDG PET/CT improve diagnostic accuracy in suspected infective endocarditis.

Background: The purpose of this study was to identify semiquantitative parameters of [F]FDG PET/CT using a digital PET scanner, which may increase diagnostic accuracy and readers' confidence in the diagnosis of infective endocarditis (IE).

Results: Images of 82 patients undergoing [F]FDG PET/CT for suspected IE were visually and semiquantitatively analyzed. Standardized uptake values (SUV) of suspected foci, also normalized to liver, mediastinum and surrounding activity were calculated. For each, best thresholds were identified to diagnose endocarditis. Final diagnosis was reached by consensus in a multidisciplinary board. Semiquantitative analysis (SUV/SUV mediastinum, SUV/SUV liver, SUV/SUV mediastinum, SUV/SUV liver, SUV/SUV liver, SUV/SUV mediastinum, SUV focus/SUV focus, SUV/SUV surrounding) added to visual interpretation increased sensitivity (57-86%), specificity (83-93%), PPV (64-86%), NPV (79-93%) and diagnostic accuracy (74-90%) when using best SUVs thresholds (all p < 0.05).

Conclusions: Combining visual and semiquantitative analysis allows for a more accurate diagnosis of IE, and might be implemented into clinical routine.