In vivo imaging of cartilage degeneration using mu CT-arthrography

Objective: In vivo imaging of cartilage degeneration in small animal models is nowadays practically impossible. In the present study, we investigated the use of micro-computed tomography (mu CT) in combination with a negatively charged ionic iodine dimer (ioxaglate) for in vivo assessment of cartilage degeneration in a small animal model. Methods: Cartilage degeneration was induced in the right knee of rats by injection of mono-iodoacetate (MIA). We imaged the rat knees with ioxaglate enhanced mu CT-arthrography at 4, 16 and 44 days after MIA injection. Subsequently, mu CT-arthrographic findings were evaluated and compared with quantitative histology of the patellar cartilage. Results: In vivo mu CT-arthrography clearly detected cartilage degeneration in the rat knee-joints, in which the ioxaglate diffused into the degenerated cartilage layer. Higher mu CT-attenuation values and smaller total volumes of the cartilage layer were detected at longer time periods after MIA injection, which is quantitatively confirmed by histology. Conclusion: In vivo mu CT-arthrography is a valuable tool for detection of minor cartilage alterations and distinguishes different stages of cartilage degeneration in a small animal model. Since mu CT, at the same time, also visualizes osteophyte formation and changes in the underlying subchondral bone structures, the technique will be very useful for longitudinal overall assessment of the development of (osteo)arthritis and to study interventions in small animal models. (C) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.