Potential clinical implication of (18) F-FDG PET/CT in diagnosis of periprosthetic infection and its comparison with (18) F-Fluoride PET/CT.

Abstract

The differentiation between septic and aseptic loosening of prosthetic hip joint is a major challenge for the clinician. This study assessed and compared the diagnostic accuracy of (18) F- flouro-deoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT) with (18) F-fluoride PET/CT for diagnosis of infection in the painful hip prosthesis. In this prospective study, we included the patients with painful hip prostheses with radiological or clinical suspicion of loosening, those who had given the written consent and scheduled for clinical and diagnostic evaluation before revision arthroplasty. To rule out the nature of loosening (septic vs. aseptic), all the patients underwent (18) F-Fluoride PET/CT and (18) F-FDG PET/CT. The reference standard for periprosthetic infection was based on histopathology and/or microbial culture and/or intraoperative findings. We prospectively evaluated 42 patients of hip prostheses before revision arthroplasty. Visual and semi-quantitative analysis of both the positron emission tomography (PET) images was done and the results were compared with a reference standard. The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) and accuracy of (18) F-FDG PET/CT were 93.7%, 92.3%, 88.2%, 96% and 92.8% respectively. The sensitivity, specificity, PPV, NPV and accuracy of (18) F-fluoride PET/CT were 75%, 96.1%, 92.3%, 86% and 88.1% respectively. FDG PET/CT has higher sensitivity, NPV and accuracy as compared to compared to Fluoride PET/CT and comparable specificity and PPV. Fluoride PET/CT had shown slightly higher specificity than FDG-PET/CT, but the overall diagnostic performance of FDG-PET/CT in periprosthetic infection is optimal in routine clinical practice and better than fluoride PET/CT.