FDG Uptake Pattern of a Prosthetic Graft without Infection on a PET/CT Scan

Kim, Man Ki; Yun, Woo Sung; Kwun, Woo Hyung; Kong, Eun Jung; Cho, Ihn Ho; Suh, Bo Yang

Abstract

PURPOSE
A prosthetic graft infection is a rare but often disastrous complication during vascular surgery. Diagnosis of a prosthetic graft infection is not always easy, particularly with a low virulent bacterial infection or in a deeply placed graft in the retroperitoneal space. Recently, fludeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has been proposed as a diagnostic modality for prosthetic graft infection. However, some reports have indicated that high FDG uptake occur in grafts without infections. This study analyzed FDG uptake patterns in prosthetic grafts of asymptomatic patients.
METHODS
We reviewed 14,545 patients who had received PET/CT in a tertiary hospital between July 2007 and March 2010. Of them, 11 patients who had undergone previous bypass surgery with a prosthetic graft were identified. Four underwent an aortic bypass and the others received lower extremity bypass grafting. PET/CT images and patient clinical data were reviewed retrospectively. The maximum standardized uptake value (SUVmax, A) in the graft, the mean SUV (SUVmean, B) of the blood-pool, and the target-to-background ratio (T/B, A/B) were calculated.
RESULTS
The mean duration between bypass grafting and the PET/CT scan was 21 months (range, 1~80 months). No clinical evidence of graft infection was observed in any of the patients. PET/CT revealed an uneven, diffuse FDG uptake pattern on the grafts, and the mean T/B was 2.0 (range, 0.9~4.6). T/B was greater than 2.0 in six patients (55%).
CONCLUSION
A prosthetic graft without an infection can result in increased FDG uptake during PET/CT. A further prospective study is necessary to evaluate the usefulness of FDG PET/CT for diagnosing a prosthetic graft infection.