Gadolinium-enhanced magnetic resonance imaging of the knee: an experimental approach

The purpose of this study was to examine gadolinium-enhanced magnetic resonance imaging (MRI) for monitoring cartilage degeneration.

This is a proof-of-concept study in an animal model. Adult New Zealand rabbits were randomly stratified into five groups. Papain was injected intra-articularly in the right knee in four groups to establish the stages of cartilage degeneration. The left knee and group 5 served as controls. Bilateral MRI was performed 24 h after the initial injection of papain, and 1 week, 1 month, and 3 months following three papain injections. Injection of the contrast agent was followed by bilateral MRI examination immediately upon injection, and at 2 and 4 h post-injection. Signal intensities of articular cartilage and peripheral soft tissues were obtained before animals were sacrificed. Post-mortem bilateral cartilage specimens were studied histologically.

Histopathology results verified the staged degeneration of papain-treated articular cartilage. Differences in cartilage signal intensity were significant for the staged model using a special three-dimensional MRI method (P < 0.05) but not using ordinary MRI. No differences were observed within or between the control groups (P > 0.05).

Contrast-enhanced MRI examination may be a viable tool for early diagnosis of osteoarticular disease. Prospective studies are warranted to evaluate the potential for clinical application.