Raghvinder P. Gambhir, Pritee Padgaonkar, Varinder Bedi, Surinder Singh
Vascular Surgery, Army Hospital, Delhi, India.
OBJECTIVES: To evaluate the utility of 18 F-FDG PET CT in the diagnosis of abdominal and peripheral vascular graft infections.
METHODS: All patients with suspected graft infection in a study period of 18 months were included in the study. Detailed history, clinical examination along with complete cell count, CRP, ESR and blood cultures were obtained. All underwent CT angiography and FDG-PET CT. Protocol used was: whole body PET/CT scan (base of skull to mid-thigh) 45 minutes after intravenous injection of 18F-FDG at 0.15 mci/ kg body weight. Images were reconstructed and reformatted 3-D image and fusion images of PET and CT were also obtained to give accurate anatomical correlation. SUV max values indicated a positive report/ infectious event. Microbiological cultures were obtained from explanted grafts and tissue aspirates.
RESULTS: Twelve patients with suspected graft infection were included in the study. Male-to-female ratio was 11:1; median age was 56 years (43-70 years). Time interval between index surgery and presenting complaints varied from 6 weeks to 12 years. Presentation included discharging sinus, pseudo aneurysm, or nonspecific symptoms like erythema, fever and pain. Nine patients showed increased 18F-FDG uptake within the graft and in surrounding soft tissue, 2 showed increased up take in surrounding soft tissue alone and in one patient no uptake was seen within the graft/soft tissue. FDG PET CT had a sensitivity of 100%, Specificity of 66.6%, a positive predictive value of 87.5% and a negative predictive value of 100%. Klebsiella, pseudomonas, E coli and Morganella Morgagni were the common organisms isolated.
CONCLUSIONS: 18F-FDG PET/CT is a reliable noninvasive imaging modality for the diagnosis of vascular graft-related infection. The precise anatomic localization of increased 18F-FDG uptake provided by PET/CT enables accurate differentiation between graft and soft-tissue infection. It is the future gold standard test.
AUTHOR DISCLOSURES: V. Bedi: Nothing to disclose; R. P. Gambhir: Nothing to disclose; P. Padgaonkar: Nothing to disclose; S. Singh: Nothing to disclose.
Posted April 2013