¹⁸F-FDG microPET imaging differentiates between septic and aseptic wound healing after orthopedic implant placement

Abstract

Background and purpose ¹⁸F-FDG PET is a widely used tool for molecular imaging of oncological, cardiovascular, and neurological disorders. We evaluated ¹⁸F-FDG microPET as an implant osteomyelitis imaging tool using a Staphylococcus aureus-induced peroperative implant infection in rabbits.

Methods Intramedullary titanium nails were implanted in contaminated and uncontaminated (control) proximal right tibiae of rabbits. Tibiae were quantitatively assessed with microPET for ¹⁸F-FDG uptake before and sequentially at 1, 3, and 6 weeks after surgery. Tracer uptake was assessed in soft tissue and bone in both treatment groups with an additional comparison between the operated and unoperated limb. MicroPET analysis was combined with radiographic assessment and complementary histology of the tibiae.

Results At the first postoperative week, the ¹⁸F-FDG uptake in the contaminated implant group was significantly higher than the preoperative measurement, without a significant difference between the contaminated and uncontaminated tibiae. From the third postoperative week onward, ¹⁸F-FDG uptake allowed discrimination between osteomyelitis and postoperative aseptic bone healing, as well as quantification of the infection at distinct locations around the implant.

Interpretation ¹⁸F-FDG-based microPET imaging allows differentiation between deep infection and undisturbed wound healing after implantation of a titanium intramedullary nail in this rabbit model. Furthermore, our results indicate that ¹⁸F-FDG PET may provide a tool in human clinical diagnostics and for the evaluation of antimicrobial strategies in animal models of orthopedic implant infection.

JO participated in the design of the study and performed the initial experiments and data collection, the statistical analysis, and data interpretation, and he also wrote the initial draft of the manuscript. BB participated in the study design, coordination, and interpretation of data, and helped to write the manuscript. TW participated in the study design and coordination and helped to write the manuscript. GW participated in the study design and coordination and helped to write the manuscript.

This study was funded by the Dutch BioMedical Materials program, co-funded by the Dutch Ministry of Economic Affairs. This study is part of the BMM NANTICO Research Project. We thank the employees of the animal facility of the Maastricht University Medical Center for their assistance during this study. We also thank I. Pooters, M. Visser and C. Urbach of the Nuclear Medicine department of the Maastricht University Medical Center for their support during this study, and R. Odekerken for his assistance with the design of the experimental setup. We are very grateful to S. Bout and P. Dijkstra for their overall support during this study.

No competing interests declared.