FDG-PET/CT in infected and non-infected prosthetic vascular grafts

Prosthetic vascular graft infections (PVGI) pose a significant clinical challenge due to high morbidity and mortality. FDG-PET/CT has emerged as a promising diagnostic tool, however, differentiating between infected and non-infected grafts is complex because non-infected grafts can also exhibit inflammatory FDG uptake. This overlap complicates interpretation, necessitating the refinement of diagnostic criteria. We evaluated the diagnostic utility of FDG-PET/CT in distinguishing infected from non-infected grafts, focusing on FDG uptake intensity and pattern while determining optimal semi-quantitative thresholds. A retrospective analysis was conducted on 80 patients who underwent FDG-PET/CT and had either infected or non-infected grafts. FDG-PET/CT images were analyzed based on FDG uptake intensity using a visual grading scale, FDG uptake pattern, and semi-quantitative parameters such as standardized uptake value (SUV) and target-to-background ratio (TBR). FDG uptake intensity assessment demonstrated that 92.6% of PVGI patients exhibited grade 3 uptake, compared to 62.3% of non-infected patients. Analysis of FDG uptake patterns also showed a significant difference, with focal uptake observed in 66.7% of infected patients versus 20.8% of non-infected patients. PVGI patients displayed significantly higher median SUVmax and TBR values than non-infected grafts. An SUVmax threshold of 6.2 demonstrated a sensitivity of 70% and a specificity of 79% for PVGI diagnosis. Similarly, a TBR cutoff of 3.3 yielded a sensitivity of 74% and a specificity of 81%. FDG-PET/CT is increasingly recognized as a valuable diagnostic tool for PVGI, particularly through the assessment of uptake intensity, pattern, SUVmax, and TBR parameters. Our study strengthens its established role and provides important data that may help refine diagnostic thresholds, further enhancing its utility in clinical practice. However, cautious interpretation remains essential to avoid unnecessary procedures.