The Study Of Microstructures In Diseased Bones By Solid-State Nuclear Magnetic Resonance And Magnetic Resonance Micro-Imaging

The advent of an aging society has increased the incidence of osteoarthritis and osteoporosis,which brings enormous challenges for the medical system and the whole society.Therefore,exploring the pathogenesis of the two diseases and seeking effective treatment programs have become an important topic in bone research field.To this end,solid-state nuclear magnetic resonance(SSNMR)and high-field magnetic resonance(MR)micro-imaging have been used to assist the basic research in bones.In this thesis,We focused on the study of changes in the microstructures in diseased bones using both SSNMR and MRI at the high magnetic field.In the first part,we analyzed 31P NMR signal and 31P-1H heteronuclear correlation spectra in SSNMR experiments from bones of different animal models and human patients.We found that the relative content for amorphous calcium phosphate(ACP)of calcium phosphate(CaP)in diseased bones is notably different to normal healthy bones.The ACP ratio increases with increasing bone mineral and decreases with decreasing bone mineral.This result is supported by the analysis of micro-CT and Raman spectroscopy.The above research shows that the quantitation of ACP ratio could potentially be used to determine the mechanical strength and quality of bone tissue,and could also be used to correlate the stage of OA progression.Simultaneously,it demonstrates that SSNMR measurements can offer new metrics in the analysis of bone quality and therefore useful in the evaluation of the efficacy of medical treatment on bone health in animal models.In the second part,we studied the tibia bones from Osteosclerosis mice by MR micro-imaging at the field of 14.1 tesla and analyzed T2-weighted images and diffusion weighted images.We found that in diseased bone the T2 was shorter and the apparent diffusion coefficient(ADC)is smaller than normal healthy bones,which suggested that the water molecule movement was more restricted,the pore size was smaller and the pore connectivity was reduced in the bone microstructure.The above preliminary research demonstrates that MRI can achieve high spatial resolution at the high magnetic field and provide detailed bone microstructure information.