| Osteoarthritis is one of the most prevalent chronic diseases in the United States and worldwide. Characteristic changes in the macromolecular matrix of articular cartilage occur during osteoarthritis including a decrease in proteoglycan content and disruption of the highly organized collagen fiber network. Techniques to non-invasively assess the cartilage macromolecular matrix would be beneficial in osteoarthritis research studies to monitor disease-related and treatment-related changes in the composition and ultra-structure of cartilage.;Cross-relaxation imaging (CRI) is a qMT method which can acquire three-dimensional parametric maps of articular cartilage measuring the fraction of macromolecular bound protons (f), the exchange rate constant between macromolecular bound protons and free water protons (k), and the T2 relaxation time of macromolecular bound protons (T2B) with high resolution and relatively short scan time based upon a limited number of MT-contrast images. Modified Cross-Relaxation Imaging (mCRI) is a qMT model closely based from CRI, which corrects for parametric biases due to T1 mapping. This work utilizes mCRI to model qMT parameters in cartilage.;The goal of this work is to develop non-invasive MRI biomarkers for assessing the content and ultra-structure of the cartilage. This work addresses multiple aspects of biomarker development, including model selection, protocol optimization, clinical feasibility, ex-vivo protocol development, and acceleration techniques for faster acquisitions. |
