Introduction: Infective endocarditis (IE) is a very
heterogeneous condition for several reasons. The diagnosis can be notoriously
difficult. A delay in diagnosis can have severe consequences. Even proper
application of the Duke criteria cannot solve all cases. For this reason,
positron emission tomography / computer tomography (PET/CT) with
18F-fluorodesoxyglucose (18FDG) has been proposed in the 2015 guidelines of the
European Society of Cardiology. What has been the effect of these guidelines
thus far?
Methods: A probe of the literature has been performed in
PubMed, from 2016 on using the search terms “endocarditis AND PET”. PET with
18-fluoro-desoxyglucose (18-FDG) as marker for increased metabolism can serve
such as in inflammation, infection and malignancies.
Results: One hundred items were identified, of which 41
documents could be retained. However, only 16 were original series, mostly with
low numbers. The other manuscripts were editorials, comments, reviews and
“image vignettes”. PET/CT increased the sensitivity of the Duke criteria in
cases of prosthetic valve endocarditis (PVE), but in a much lesser degree in
native valve endocarditis (NVE). Patient preparation should be standardized in
order to reduce the uptake of 18FDG by the myocardium. This includes low
carbohydrate – high fat diet, fasting and unfractionated heparin
administration. Furthermore, image acquisition and processing (quantification,
correction for attenuation, taking into account implanted metallic materials)
should also be standardized. Infection and inflammation of other causes such as
postoperative healing and foreign body reaction should be discerned because of
their different management and outcome. Scintigraphic techniques, based on
radiolabeled WBC can serve as complement for distinction between sterile
inflammation and infection. Effects of antibiotics (negative imaging results
before cure) and inflammation (especially healing after operation and use of
biological glue materials) should be taken into account. Radiolabeled white
blood cell scintigraphy could be a valuable adjunct in these cases. The
detection of extra- cardiac foci (especially tumors which can serve as port of
entry and septic emboli) is an additional advantage.
Conclusion: PET/CT seems a valuable tool to
increase the accuracy in diagnosing IE, especially PVE. Early postoperative
cases must be interpreted with caution. To confirm the value of PET/CT, the
major centers should standardize their method. This allows comparison of
results of larger patient groups, which could be collected in the International
Collaboration of Endocarditis – Prospective Cohort Study. A standardized method
for patient preparation, imaging acquisition and processing is needed. This can
best be undertaken through the International Collaboration on Endocarditis–
Prospective Control Study ICE-PCS. Nuclear cardiologists should also be
included in “endocarditis teams.
Author(s) Details:
Wilhelm P. Mistiaen,
Department
of Health and Social Care, Artesis Plantijn University College Antwerp, Belgium
and Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.
Please see the link here: https://stm.bookpi.org/ACMMR-V12/article/view/12972
