18F-FDG PET-CT in suspected prosthetic vascular graft infection

Diagnosis of prosthetic vascular graft infections is a clinical challenge, and surgical therapy is associated with comorbidity. Therefore, accurate diagnostic methods are required for their optimal management.

A 61-year-old-patient presented with erysipelas of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. He had been first treated for suspicious of septic arterial thrombosis or false aneurysm with antibiotics. A computed tomography (CT) angiogram was performed to detect any potential infection of the bypass and to explore erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass. The 2-[18F]-fluoro-2-desoxy-d-glucose positron emission tomography (18F-FDG PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft. Therefore, the bypass was considered as noninfected and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh with a C-reactive protein level significantly decreased to 36 mg/L and a normal white blood cell count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues and still no uptake of the graft.

In conclusion, this case highlights the role that 18F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities.