Role of 18F-FDG PET/CT in diagnosis of cardiovascular infection in patients after cardiac surgery

Abstract

Abstract Purpose To investigate the diagnostic performance of 18F-FDG PET/CT in patients with suspected prosthetic valve infective endocarditis (IE), prosthetic aortic and intracardiac device infection. Methods The prospective analysis included results of PET/CT examinations performed in 60 patients with fever of unknown origin after cardiac surgery (median time 29 months): valve replacement (n=26), intracardiac device implantation (n=19), both procedures (n=8), Bentall-de-Bono surgery (n=7). According to the Duke criteria most patients – 90% (54/60) – had possible (n=42) and rejected (n=12) diagnosis of IE; 6 patients had definite IE. PET/CT scan was performed 90 min after intravenous injection of 18F-FDG (175–200MBq). All patients underwent strict carbohydrate-free diet and fasted for at least 15–18 hours. Final diagnosis was based on clinical, laboratory, instrumental and intraoperative (n=41) data: confirmed in 40 and ruled out in 20 patients. Results PET/CT results correctly confirmed the infectious process in the prosthetic valve area, aortic prosthesis or along the intracardiac device in 93% (37/40) and ruled it out in 75% (15/20) patients. False results were obtained in 13% (8/60) – positive (n=5) and negative (n=3). Thus, in the analyzed group of patients (n=60), the sensitivity, specificity and diagnostic accuracy of PET/CT with 18F-FDG in the diagnosis of IE were 93%, 75% and 83%, respectively; positive and negative predictive value – 88% and 83%. In patients with possible IE according to the Duke criteria, true PET/CT results were obtained in 86% (36/42) – positive (n=28) and negative (n=8). In 7% (4/60) of patients – the diagnosis was based only on PET/CT, while initially, according to the Duke criteria, it was rejected. In addition, in 40% (24/60) of patients of the analyzed group, whole body PET/CT revealed other than valve and device, previously unknown foci of inflammation: in the lungs (n=6), in the sternum (n=6), in the area of the native valve (n=3), in the mediastinum (n=4), other (n=13). Conclusions 18F-FDG PET/CT proved to be highly informative for the diagnosis of infectious processes in the heart and vessels in patients after cardiac surgery. The inclusion of PET/CT in the diagnostic algorithm for this category of patients reduces the number of patients with possible IE according to the Duke criteria. Funding Acknowledgement Type of funding source: None