Abstract 12920: The Value of 18 FDG PET/CT in the Diagnostic Work-Up of Patients With Possible Infective Endocarditis
The diagnosis of infective endocarditis (IE) is sometimes difficult when there are discrepancies between blood cultures, transesophageal echocardiography (TEE) and clinical judgment. The aim of this study was to assess the incremental diagnostic value of 18F-FDG-PET/CT in 45 consecutive patients (73% male, mean age 61 ± 26 years) with suspected IE and inconclusive tests at admission. In 28 patients (19 with a cardiac valvular (15) or nonvalvular (4) device) with blood cultures positive for germs typically involved in IE the initial TEE was negative or inconclusive. In 10 patients presenting with fever TEE identified cardiac lesion possibly related to IE (ruptured mitral chordae, thickened valve leaflet, thickened prosthetic annulus), but blood cultures were persistently negative. Finally, 7 patients had metastatic or embolic lesions and a predisposing cardiac condition, but TEE was negative. When previous unknown lesions detected by PET/CT were confirmed by succeeding examinations, they were considered true positives. When PET/CT was negative, it was compared with the final diagnosis that was defined according to the modified Duke criteria determined during a 6-month follow-up. Thirty patients had definite IE at the end of the follow-up, 3 had possible IE, and in 12 patients the diagnosis was rejected. Twenty-seven patients (60%) exhibited abnormal FDG uptake around the cardiac valves, and 12 (27%) had extracardiac accumulation. In 5 patients the initial negative TEE became positive a mean 5 ±7 days after PET/CT had been performed The sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were as follows (95% confidence interval): 87% (68% to 95%), 67% (38% to 87%), 84% (65% to 94%), and 71% (42% to 92%), respectively. Adding abnormal FDG uptake as a new major criterion significantly increased the sensitivity of the modified Duke criteria at admission (68% [53% to 82%] vs. 96% [88% to 99%], p = 0.01). This result was due to a significant reduction (p < 0.001) in the number of possible IE cases. In conclusion PET/CT increases the diagnostic accuracy for IE in the subset of patients with possible IE and may help to manage a challenging situation.
Author Disclosures: F. Chirillo: None. F. Boccaletto: None. P. Pantano: None. A. De Leo: None. M. Possamai: None. W.O. Inoiosa: None. P. Scotton: None. Z. Olivari: None.
- © 2014 by American Heart Association, Inc.