Linking in vivo MRI with biochemical, biomechanical and genetic profiles in osteoarthritis

Principal Investigator: Xiaojuan Li

Osteoarthritis (OA) is a major health concern affecting more than 25 million people in the U.S. Current treatment of OA is very limited, and developing new therapeutic strategies is becoming increasingly important. The disease is primarily characterized by articular hyaline cartilage degeneration. Understanding the biochemical and biomechanical changes in cartilage matrix as well as molecular alterations in chondrocytes can provide further understanding of the disease pathogenesis and clues for new therapeutic targets. Furthermore, there is clearly a need for in vivo imaging techniques that can noninvasively and critically evaluate the therapeutic efficacy of new treatment methods. The overall goal of this project is to investigate the relationships between advanced in vivo MRI parameters and the associated biochemical and biomechanical changes, and genetic profiles in OA cartilage. Figure 1 shows the diagram of this study.

This project encompasses several subprojects, described on the following pages:

• Correlation between MR T1rho relaxation time and proteoglycan contents in OA cartilage
• Comparison of quantitative imaging of cartilage for osteoarthritis: T2, T1rho, dGEMRIC, and
   contrast-enhanced CT
• High resolution magic angle spinning (HR-MAS) spectroscopy analysis of OA cartilage
• Cellular characterization — bone marrow edema-like lesions
• Relationship between magnetic resonance T1ρ relaxation mapping of articular cartilage and
  biomechanical properties