The additional role of 18F-FDG PET/CT in prosthetic valve endocarditis

The purpose of the present review is an update on the diagnosis of prosthetic valve endocarditis (PVE), evaluating the additional value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to the standard modified DUKE criteria on which for a long time is based the diagnostic strategy of the disease.

We did a comprehensive research on the studies reported in the literature and regarding the employment of 18F-FDG PET/CT in the early diagnosis of PVE in patients with suspected disease. Scientific databases have been examined such as Medline and PubMed, followed by a review of citations and reference lists. The research included the following terms: infective endocarditis, prosthetic heart valve and cardiac valve replacement infections, 18F-FDG PET/CT and endocarditis.

The recent studies reported in the literature on the PVE diagnostic approaches showed elevated sensitivity and specificity values of 18F-FDG PET/CT ranging from 73 to 96.6% and from 80 to 94%, respectively, reducing the number of misdiagnosed patients. The usefulness of the radioisotopic procedure is even more important when the other diagnostic conventional diagnostic tools, such as echocardiography, are inconclusive or negative in patients in whom the diagnosis of PVE is definitively ascertained. However, false negative and positive results of 18F-FDG PET/CT were also ascertained in some studies interfering with image interpretation even if such limitation can be reduced with an adequate patient preparation, with a better knowledge of clinical course of the disease, of the treatment in progress and of the different technical aspects of the method.

In different studies reported in the literature, 18F-FDG PET/CT proved to improve the diagnostic accuracy of the conventional modified DUKE criteria in patients with suspected IE, and in particular with PVE, giving the highest diagnostic performance and providing additional diagnostic benefits. Thus, the radioisotopic hybrid procedure should be included in the diagnostic protocol of PVE as complementary tool to modified DUKE criteria. Finally, the usefulness of 18F-FDG PET/CT in monitoring the response to antibiotic therapy, although the few data reported in the literature are encouraging, needs more numerous studies and with a major number of cases.