Assessment of the diagnostic accuracy of18F-FDG PET/CT in prosthetic infective endocarditis and cardiac implantable electronic device infection: comparison of different interpretation criteria.
OBJECTIVE
The diagnosis of prosthetic valve (PV) infective endocarditis (IE) and infection of cardiac implantable electronic devices (CIEDs) remains challenging. The aim of this study was to assess the usefulness of18F-FDG PET/CT in these patients and analyse the interpretation criteria.


METHODS
We included 41 patients suspected of having IE by the Duke criteria who underwent18F-FDG PET/CT. The criteria applied for classifying the findings as positive/negative for IE were: (a) visual analysis of only PET images with attenuation-correction (AC PET images); (b) visual analysis of both AC PET images and PET images without AC (NAC PET images); (c) qualitative analysis of NAC PET images; and (d) semiquantitative analysis of AC PET images.18F-FDG PET/CT was considered positive for IE independently of the intensity and distribution of FDG uptake. The gold standard was the Duke pathological criteria (if tissue was available) or the decision of an endocarditis expert team after a minimum 4 months follow-up.


RESULTS
We studied 62 areas with suspicion of IE, 28 areas (45 %) showing definite IE and 34 (55 %) showing possible IE. Visual analysis of only AC PET images showed poor diagnostic accuracy (sensitivity 20 %, specificity 57 %). Visual analysis of both AC PET and NAC PET images showed excellent sensitivity (100 %) and intermediate specificity (73 %), focal uptake being more frequently associated with IE. The accuracy of qualitative analysis of NAC PET images depended on the threshold: the maximum sensitivity, specificity and accuracy achieved were 88 %, 80 %, 84 %, respectively. In the semiquantitative analysis of AC PET images, SUVmax was higher in areas of confirmed IE than in those without IE (∆SUVmax 2.2, p < 0.001). When FDG uptake was twice that in the liver, IE was always confirmed, and SUVmax 5.5 was the optimal threshold for IE diagnosis using ROC curve analysis (area under the curve 0.71).


CONCLUSIONS
The value of18F-FDG PET/CT in the diagnosis of suspected IE of PVs and CIEDs is highly dependent on patient preparation and the method used for image interpretation. Based on our results, the best method is to consider a study positive for IE when FDG uptake is present in both AC PET and NAC PET images.
Department of Nuclear Medicine, Clínico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain. anajimenezb@hotmail.com.
Ana
A
Jiménez-Ballvé
Department of Nuclear Medicine, Clínico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
María Jesús
MJ
Pérez-Castejón
Department of Nuclear Medicine, Clínico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain. rbiolton@gmail.com.|Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), University of La Rioja, C/Piqueras 98, Logroño, 26006, La Rioja, Spain. rbiolton@gmail.com.
Roberto C
RC
Delgado-Bolton
Department of Cardiology, Clínico San Carlos University Hospital, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
Cristina
C
Sánchez-Enrique
Department of Cardiology, Clínico San Carlos University Hospital, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
Isidre
I
Vilacosta
Department of Cardiology, Clínico San Carlos University Hospital, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
David
D
Vivas
Department of Cardiology, Clínico San Carlos University Hospital, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
Carmen
C
Olmos
Research Unit, Clínico San Carlos University Hospital, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
Manuel E Fuentes
ME
Ferrer
Department of Nuclear Medicine, Clínico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, C/Prof. Martín Lagos s/n, 28040, Madrid, Spain.
José L
JL
Carreras-Delgado
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004696:Endocarditis / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging* / Q000209:etiology; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Cardiac implantable electronic devices; Duke criteria; FDG; Infective endocarditis; PET/CT; Prosthetic valve