FDG PET/CT in Assessment of Prosthetic Joint Infection

Abstract

The indications and potential use of FDG PET CT in prosthetic joint infection (PJI) have not evolved fully. Most studies have compared the accuracy of FDG PET/CT with clinical parameters and other biological and radiological markers. However, FDG PET CT can also guide tissue biopsy or aspiration to increase the yield and towards accurate diagnosis. FDG uptake in mid-shaft of the implant at the bone–prosthesis interface in hip arthroplasty or increased FDG uptake in the bone–prosthesis interface for knee arthroplasty compared with adjacent soft tissue are the usually accepted criteria for diagnosis of infection. Extra information can be actively sought for from FDG PET/CT beyond just classifying into infection present or not and include the presence of periosteal reaction, peri-prosthetic osteolysis, peri-prosthetic calcification, sinus tract description, localization of infection, extent of infection, involvement of joint space, stability of joint/prosthesis, the integrity of surrounding soft tissue etc. which can be of additional value in guiding the orthopedic surgeon in the management of these patients. If PJI is due to hematogenous spread of infection then, FDG PET/CT may additionally help in localization of distant source of infection. The heterogeneity of criteria, lack of specificity in diagnosis, and relatively lower yield of PET studies suggest that they should be examined further by larger prospective trials.