Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis: increased valvular 18F-fluorodeoxyglucose uptake as a novel major criterion.

OBJECTIVES: This study sought to determine the value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for diagnosing prosthetic valve endocarditis (PVE).

BACKGROUND: The diagnosis of PVE remains challenging. In PVE cases, initial echocardiography is normal or inconclusive in almost 30%, leading to a decreased diagnostic accuracy for the modified Duke criteria.

METHODS: We prospectively studied 72 consecutive patients suspected of having PVE. All of the patients were subjected to clinical, microbiological, and echocardiographic evaluation. Cardiac PET/CT was performed at admission. The final diagnosis was defined according to the clinical and/or pathological modified Duke criteria determined during a 3-month follow-up.

RESULTS: Thirty-six patients (50%) exhibited abnormal FDG uptake around the site of the prosthetic valve. The sensitivity, specificity, positive predictive value, negative predictive value, and global accuracy were as follows (95% confidence interval): 73% (54% to 87%), 80% (56% to 93%), 85% (64% to 95%), 67% (45% to 84%), and 76% (63% to 86%), respectively. Adding abnormal FDG uptake around the prosthetic valve as a new major criterion significantly increased the sensitivity of the modified Duke criteria at admission (70% [52% to 83%] vs. 97% [83% to 99%], p = 0.008). This result was due to a significant reduction (p < 0.0001) in the number of possible PVE cases from 40 (56%) to 23 (32%).

CONCLUSIONS: The use of (18)F-FDG PET/CT was helpful for diagnosing PVE. The results of this study support the addition of abnormal FDG uptake as a novel major criterion for PVE.