In vivo characterization of morphological properties and contact areas of the rat cartilage derived from high-resolution MRI

Abstract Knee osteoarthritis deals with the loss of cartilaginous substances. Biomaterial implant using mesenchymal stromal cells was usually used to perform cartilage regeneration. The bio-integration and biofunctionality assessments of the used biomaterial implant on the injury sites require the longitudinal monitoring of the cartilage over times. The aim of this present study was to develop a characterization framework of the cartilage in knee osteoarthritis especially its morphological properties and contact areas derived from high-resolution magnetic resonance imaging (MRI) technique. Manual segmentation procedure was applied for extracting cartilage from surrounding biological tissues. Geometrical computing techniques were applied to calculate characterization properties of the rat cartilage. As clinical case study, curvature, thickness, volume and relative contact area properties of the rat cartilage in knee osteoarthritis were quantified on each knee full model and/or its region of interest (ROI) models. We found that the cartilage thickness and volume of three cartilage compartments decrease at the beginning (from 7 to 28 days). Tibial cartilage thickness increases at the end of the osteoarthritis process (from 28 to 56 days). This is due to the fact that the cartilage swelling occurred during osteoarthritis process. These findings were confirmed when observing cartilage curvature; we noted that there is an increasing curvature due to the incurvation effect of the cartilage during osteoarthritis process. The relative contact areas of three cartilage compartments increase slightly. However, the difference between control knees and osteoarthritis knees is significant. ROIs analyses of the thickness and curvature properties were also reported on the femoral and tibial cartilages.