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

Abstract

Background and purpose18F-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.MethodsIntramedullary 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.ResultsAt 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.Interpretation18F-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.

In vitro imaging of bacteria using 18F-fluorodeoxyglucose micro positron emission tomography

“…Furthermore, the view that 18 F-FDG-PET imaging enables the visualization of bacterial infections and evaluation of antimicrobial therapy has been confirmed in animal experiments and clinical studies 14 – 18 . On the other hand, diagnosing infections with 18 F-FDG-PET still remains challenging due to the fact that, for instance, malignancies, sterile inflammation and physiological wound healing, may result in similarly high levels of 18 F-FDG uptake as infections 9 , 15 – 17 .…”

The Longitudinal Assessment of Osteomyelitis Development by Molecular Imaging in a Rabbit Model

“…The inoculation dose and preparation were based on previous studies [6, 7]. To confirm the inoculum size, the bacterial count of every inoculum was verified by quantitative culture on tellurite glycine agar (Difco, Becton Dickinson, France) before and after surgery.…”

“…The micro-CT-images were acquired on an X-rad 225 (Precision X-ray, USA) as described previously [6, 7]. …”

“…By combining the results of this study with our previously reported studies [ 6 , 7 ], we also aimed to identify the most relevant parameters to diagnose naïve osteomyelitis by experimental conditions and describe how these infection parameters may differ in case of the presence or absence of an orthopaedic implant.…”

Tendon Graft Healing in Multiligament Reconstructed Knee Detected by FDG-PET/CT: A Pilot Study

“…Based on earlier data, high early SUV of the grafts are likely to represent postoperative inflammation which gradually fades. The increased glycolytic activity could be a sign of disturbing or non-beneficial healing when surgery is not likely to explain observed metabolism any more (18,19). Sorensen et al (20) investigated bone metabolism with 18 F-Fluoride and PET.…”