Biomechanics and Relaxivity for Functional Imaging of Articular Cartilage Injury and Degradation

Fites, Kateri Elizabeth. M.S.B.M.E., Purdue University, May 2014. Biomechanics and relaxivity for functional imaging of articular cartilage injury and degradation. Major Professsor: Corey P. Neu. Osteoarthritis (OA) is a major debilitating health concern and economic burden worldwide, affecting 27 million people in the United States alone. OA often follows tissue injury, and is marked by changes in the structure and biomechanical function of cartilage, including breakdown of extracellular matrix molecules, loss of bulk tissue stiffness, and increase in articular surface friction and wear. Unlike bone and many other tissues, cartilage lacks an intrinsic capacity for regeneration. Advanced OA is typically diagnosed by patient symptoms (e.g. joint pain) and confirmed by radiographic evaluation of joint space narrowing. However, the application of functional imaging to assess cartilage physiology may provide an early diagnosis of joint changes prior to patient symptoms. One such functional imaging modality, magnetic resonance imaging (MRI), may be used to characterize the mechanics of joint cartilage in vitro and in vivo, but it has not yet been applied to evaluate cartilage injury in defined damage models. Here, we studied the changes in MRI-assessed intratissue strain following cartilage injury, and correlate those changes with traditional assessment metrics such as relaxivity, biochemical composition, and microstructure. Osteochondral samples were harvested