High-resolution diffusivity Imaging at 3.0 T for the detection of degenerative changes - A trypsin-based arthritis model

Rationale and Objectives: To establish whether it is possible to quantitatively characterize the degenerative changes in cartilage that typify arthritis on a sub-150-mum resolution scale using a 3.0 T whole body MR-scanner with a reasonable measurement time. Materials and Methods: This problem is addressed through diffusion-microimaging investigations on an arthritis model based on the enzymatic destruction of the proteoglycans in cartilage specimen. A 35-min birdcage resonator made high spatial resolution possible, and diffusion-micro-imaging was achieved with the use of a strong gradient system. Results: Diffusion-weighted and quantitative parameter maps were acquired with 117 x 234 mum(2) pixel resolution in less than 9 minutes. Diffusivity profiles and parameter images exhibit an increase in diffusivity in degenerated tissue. Conclusion: In a trypsin-based arthritis model, the spatial localization and quantification of damaged areas have been shown to be possible on a whole body 3.0 T MR system. Measurement times achieved for these high spatial resolution studies make in vivo investigations feasible.