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Updated: Sep 18, 2025
Combined In vivo Optical and µCT Imaging to Monitor Infection, Inflammation, and Bone Anatomy in an Orthopaedic Implant Infection in Mice
Published on: October 16, 2014
Optical coherence tomography-based detection of orthopaedic implant biofilms formed by methicillin-resistant S.aureus
V Demidov1,2, N Demidova3,4, D Hazem2
1Dept. of Orthopaedics, Dartmouth Health, 1 Medical Center Dr, Lebanon, NH USA 03766.
Abstract:
Orthopaedic implant-associated infections cause serious complications primarily attributed to bacterial biofilm formation and often characterized by increased antibiotic resistance and diminished treatment response. There is currently a lack of imaging modalities that can directly visualize biofilms to determine the location and extent of contamination. Optical coherence tomography (OCT) is a portable, non-invasive, high-resolution imaging modality with the potential to fulfill this unmet need. In this study, we aim to evaluate the efficacy of OCT in detecting biofilms formed by life- and limb-threatening bacteria on orthopaedic implants. Bioluminescent strain SAP231 of methicillin-resistant S.aureus (MRSA) was used to grow biofilms on the surfaces of titanium and stainless-steel orthopaedic hardware situated inside custom-designed macrofluidic devices, allowing continuous nutrient broth supply and waste removal. Three-dimensional OCT images of each piece of hardware were obtained every 24 hours with subsequent bioluminescence imaging using the PerkinElmer IVIS Spectrum. OCT texture analysis based on multi-parametric fitting approach was developed and validated against IVIS quantification for accurate identification of live MRSA signatures. The monitoring of biofilm formation and measurement of film thicknesses starting at 12 micrometers and reaching 180 micrometers in 72 hours on metal hardware is demonstrated. This proof-of-concept study highlights the ability of OCT to detect and quantify the formation of MRSA bacterial biofilms in a high fidelity orthopaedic implant biofilm model in vitro, opening avenues for translation of this technique to preclinical models of contaminated orthopaedic trauma surgery and further clinical translation.
Insights
Optical coherence tomography (OCT) can detect and quantify bacterial biofilms on orthopaedic implants. This imaging technique shows promise for identifying infections and guiding treatment in orthopaedic trauma surgery.
Area of Science:
- Biomedical Engineering
- Infectious Diseases
- Medical Imaging
Background:
- Orthopaedic implant infections are serious complications driven by bacterial biofilms.
- Current imaging methods cannot directly visualize these biofilms, hindering diagnosis and treatment.
- Antibiotic resistance and poor treatment response are common in these infections.
Purpose of the Study:
- To evaluate the efficacy of Optical Coherence Tomography (OCT) in detecting bacterial biofilms on orthopaedic implants.
- To assess OCT's potential for visualizing biofilm location and extent.
- To explore OCT as a diagnostic tool for implant-associated infections.
Main Methods:
- Methicillin-resistant Staphylococcus aureus (MRSA) biofilms were grown on titanium and stainless-steel implants in macrofluidic devices.
- Three-dimensional OCT imaging was performed every 24 hours.
- OCT texture analysis was developed and validated against bioluminescence imaging (IVIS) for MRSA detection.
Main Results:
- OCT successfully detected and quantified MRSA biofilm formation on orthopaedic hardware.
- Biofilm thickness was monitored, growing from 12 to 180 micrometers within 72 hours.
- OCT texture analysis accurately identified live MRSA signatures, correlating with IVIS quantification.
Conclusions:
- OCT is a viable technique for detecting and quantifying bacterial biofilms on orthopaedic implants in vitro.
- This proof-of-concept study demonstrates OCT's potential for preclinical and clinical translation in diagnosing implant-associated infections.
- OCT offers a non-invasive, high-resolution imaging solution for a critical unmet clinical need.
