National audienceHigh-field magnetic resonance systems allowing high-resolution magnetic resosnance imaging -HR-MRI) is a powerful research tool to visualize and examine hyaline cartilage of small joints non-invasively. Different studies have shown that qualitative assessment of degenerative joint disease, derived from MR images, was reliable. The capability to show pathologic changes throughout the time course of the disease from three-dimensional (3D) datasets has also been demonstrated. However, in vivo quantitative imaging for an accurate determination of cartilage thickness and volume is challenging due to small size of rodent joints and dedicated coils are mandatory. Surgical articular cartilage repair therapies for cartilage defects such as osteochondral autograft transfer, autologous chondrocyte implantation or matrix associated autologous cell transplantation require non invasive technique to evaluate longitudinally the biointegration of the graft. The aim of this study was to follow using 7T MRI the biointegration of biomaterials colonized by mesenchymal stem cells or not after implantation in a calibrated full thickness focal lesion in the rat knee
