Objectives: Osteoarthritis (OA) structural changes take place over decades in humans. Magnetic resonance imaging (MRI) can provide precise and reliable information on the joint structure and changes over time. In this study, we investigated the reliability of quantitative MRI in assessing knee OA structural changes in the experimental ACL dog model of OA.
Methods: OA was surgically induced by transection of the ACL of the right knee in 5 dogs. High resolution three dimensional MRI using a 1.5 T magnet was performed at baseline, 4, 8 and 26 weeks post-surgery. Cartilage volume/thickness, cartilage defects, trochlear osteophyte formation and subchondral bone lesion (hypersignal) were assessed on MR images. Animals were sacrificed 26 weeks post-surgery and macroscopic evaluation was performed.
Results: There was a progressive and significant increase over time in the loss of knee cartilage volume, the cartilage defect, and subchondral bone hypersignal. The trochlear osteophyte size also progressed over time. The greatest cartilage loss at 26 weeks was found on the tibial plateaus and in the medial compartment. There was a highly significant correlation between total knee cartilage volume loss or defect and subchondral bone hypersignal, and also a good correlation between the macroscopic and the MRI findings.
Conclusion: This study demonstrated that MRI is a useful technology to provide a non-invasive and reliable assessment of the joint structural changes during the development of OA in the ACL dog model. The combination of this OA model with MRI evaluation provides a promising tool for the evaluation of new DMOADs.
- experimental OA
- quantitative MRI
- structural changes