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Description
Infection represents one of the most frequent causes of morbidity and mortality in patients with vascular prostheses. Prosthetic vascular graft infection (VPGI) can lead to severe and/or fatal outcomes if not early diagnosed. The Management of Aortic Graft infection Collaboration (MAGIC) criteria are used for the VPGI diagnosis. [18F]-FDG-PET/CT and radiolabeled white blood cells (WBC) scintigraphy can improve the radiologic diagnostic accuracy in PVGI. Nuclear medicine procedures are included in MAGIC criteria as minor criteria. The aim of this study is to compare [18F]-FDG-PET/CT and radiolabeled white blood cells scintigraphy in patients with PVGI. We retrospective evaluated 6 patients with suspected VPGI who underwent CT-angiography and both [18F]-FDG-PET/CT and WBC scintigraphy. According to MAGIC criteria 3 patients were classified as 'suspected infection' and 2 patients as 'confirmed infection'. Only in the patients with 'confirmed infection' both [18F]-FDG-PET/CT and WBC scintigraphy yield concordant results (both positive results) while in patients with 'suspected infection' [18F]-FDG-PET/CT was positive in 5 studies (false positive) and WBC scintigraphy was negative in all patients (true negative). We can state that, although [18F]FDG-PET/CT has a very high sensitivity, WBC scintigraphy, integrating planar with SPECT/CT images to allow better anatomical localization of findings, shows greater specificity, proving to be essential in the management of patients with vascular prosthesis infection, especially in the case of persistence of pathologic uptake of [18F]FDG despite the good clinical response to antibiotic therapy. Even if [18F]FDG-PET/CT is a valid nuclear medicine technique, especially due to its high negative predictive value, we always should pay attention to the possible false positive results due to non-specific causes of FDG uptake. The high diagnostic accuracy of WBC scintigraphy, to be confirmed in further studies with a large number of patients, should be considered as a possible major criterion for the diagnosis of VPGI.
