The development of a disease modifying osteoarthritis drugs (DMOADs) is currently limited by the inability to detect and monitor early cartilage damage that would be amenable to treatment. There is growing interest within the pharmaceutical and research community to use Magnetic Resonance Imaging (MRI) to identify biochemical and structural changes in the cartilage extra cellular matrix that occur early in the disease process. Although these techniques have been validated in small studies at single sites, multi-center evaluation of accuracy and precision, needed to apply these techniques to clinical trials of DMOADs, has not been performed. To address this need, the primary objective for this protocol is to identify and develop techniques to minimize systematic errors that decrease precision of MRI evaluation of knee cartilage, and to assess the reproducibility of the newly identified MRI techniques in measuring the cartilage morphometry and structure. Successful completion of this project may establish a multi-center imaging network in Pennsylvania for MRI evaluation of potential disease modifying osteoarthritis drugs (DMOADs) therapy.