October 13, 2021
By Razan El Ramahi, MBBS
The diagnosis of infective endocarditis (IE) is not always straightforward. Additional studies can be valuable particularly if they impact diagnosis and/or management decisions.
Duval et al. published in Clinical Infectious Diseases the results of their multicenter prospective trial, which was conducted in France to investigate the impact of using qualitative reading of 18-fluorine-fluorodeoxyglucose positron emission tomography along with computed tomography (FDG-PET/CT) on IE diagnosis and management modifications. IE classifications were performed by two IE experts at three points in time: 1) at inclusion using the Duke classification modified by Li et al., 2) after FDG-PET/CT completion (which had to be performed within 7 days of inclusion) using a modified-ESC-2015 FDG-PET/CT classification, where a positive valvular uptake is considered a major criterion and distant sites of infection as minor criterion, and 3) at month 6 (“gold standard”) where all available data except the FDG-PET/CT were reviewed. Any change in classification resulting from FDG-PET/CT data was considered beneficial if the patient was correctly reclassified compared to the 6-month gold standard classification. There was standardization in preparation and acquisition of FDG-PET/CT scans, and results were interpreted by trained physicians quantitatively and qualitatively using valve uptake patterns.
From April 2015 to March 2016, 140 patients, 70 prosthetic valve (PV) and 70 native valve (NV), were included. Duke-Li classification was modified in 24.3% and 5.7% in PV and NV patients, respectively (P = .005). When compared to gold-standard classification, modification was considered appropriate in most patients. Management modifications occurred in 21.4% of PV patients, mainly due to qualitative perivalvular uptake, and in 31.4% of NV patients, mainly due to the presence of extracardiac uptake (P = .25). Diagnosis modifications tended to occur more in patients with noncontributing echocardiography and more frequently in PV patients.
The results support the use of FDG-PET/CT in certain IE cases where diagnosis is uncertain, particularly in NV patients who do not meet definite IE criteria and when echocardiography is inconclusive, particularly in PV patients. In addition, the study sheds a light on the role of FDG-PET/CT in affecting medical and/or procedural and surgical management in PV and NV IE patients.