Diagnostic Impact of ¹⁸ F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and White Blood Cell SPECT/Computed Tomography in Patients With Suspected Cardiac Implantable Electronic Device Chronic Infection

Abstract

Background: Cardiac implantable electronic devices (CIEDs) chronic infection diagnosis is challenging because the clinical presentation is frequently misleading and echocardiography may be inconclusive. The aim of this study was to evaluate the diagnostic value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (CT) and radiolabeled white blood cells single photon emission CT/CT in a cohort of patients who underwent both scans for suspicion of CIED infection and inconclusive routine investigations. Methods: Forty-eight consecutive patients with suspicion of CIED infection who underwent both 18 F-fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT in a time span ≤30 days were retrospectively included. The final diagnosis of CIED infection by the endocarditis expert team was based on the modified Duke-Li classification at the end of follow-up. 18 F-Fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT scans were independently analyzed blinded to the patients’ medical record. Results: In the overall study population, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were respectively 80%, 91%, 80%, and 91% for 18 F-fluorodeoxyglucose positron emission tomography/CT and 60%, 100%, 100%, and 85% for white blood cell single photon emission CT/CT. Addition of a positive nuclear imaging scan as a major criterion markedly improved the Duke-Li classification at admission. Semiquantitative parameters did not allow to discriminate between definite and rejected CIED infection. Prolonged antibiotic therapy before imaging tended to decrease the sensitivity for both techniques. Conclusions: Nuclear imaging can improve the diagnostic performances of the Duke-Li score at admission in a selected population of patients with suspected CIED infection, particularly when the infection was initially graded as possible. Whenever possible, imaging should be performed before or early after antibiotic initiation.

Molecular Imaging of Cardiovascular Device Infection: Targeting the Bacteria or the Host–Pathogen Immune Response?

“…In other words, 18 F-FDG PET/CT may have the potential to quantify the severity of infection and accordingly guide patient management beyond its capacity in cardiac device infection diagnosis. This hypothesis is supported by several prior studies, though with small numbers of patients (64,65).…”

18F-FDG PET/CT improves diagnostic certainty in native and prosthetic valve Infective Endocarditis over the modified Duke Criteria

“…[9][10][11][12][13] Adding focal tracer avidity around a prosthetic valve as a major criterion to the mDC reduces the number of ''possible'' cases in a cohort of IE patients, and thus improves the diagnostic utility of these criteria. 14 The focus of these studies has been mainly limited to PVE 15 and cardiac implantable electronic device (CIED) infection, 16 where PET confers incremental benefit over TOE due to elimination of acoustic shielding. By comparison, the role of PET in native valve endocarditis (NVE) is less well studied.…”

FDG PET/CT in CIEDs infection: Don’t wait any longer!

“…4 It should be emphasized that CIED pocket/generator infection is considered ''definite'' when relevant signs are present at clinical examination, obviating the need for further diagnostic procedures. 1 In addition to the diagnosis of CIED infection, FDG PET/CT provides information on extracardiac findings 5,6 such as metastatic septic foci, which may require dedicated treatment 7 and/or infection entry site which treatment is mandatory to prevent relapse.…”

“…This limitation may be overcome by the detection of septic pulmonary emboli which are a frequent complication of CDRIE both at admission and during follow-up. 10 When the diagnosis is not definite, the presence of septic pulmonary emboli is strongly suggestive of leads infection and/or CDRIE, 5 hence both chest CT (showing peripheral lesions typically exhibiting wedge-shaped pattern with necrotic center) and PET (showing peripheral foci matching with nodules on CT) should be carefully analyzed.…”

“…This one suggests the absence of relationship probably because the overall range was short (median 7 days) so that the difference between true positive and false negative cases was small (median 11 and 15 days respectively). As a comparison, the mean delay in false negative cases was 22 day in Diemberger et al 15 and 41 days in Calais et al 5 In any case, we must bear in mind that the scan must be programmed as soon as possible in the course of the disease to ensure optimal quality and maximal impact on the therapeutic management.…”