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Objective To dynamically assess the regular pattern of both bone quantity and bone quality in a rabbit osteoporosis model induced by ovariectomy and glucocorticoid with MR spectroscopy and Micro-CT scanning,so as to explore the advantage of combining MRS with Micro-CT.Methods Sixty 8-month-old,skeletally mature,female New Zealand white rabbits were randomly allocated into three groups.Group B(n=20) underwent bilateral ovariectomy(OVX) and Group C(n=20) underwent OVX combining with daily i.m.injections of methylprednisolone sodium succinate,(MPS).Group A(n=20) were used as sham controls.Three groups underwent MR spectroscopy and Micro-CT scanning at 2,4,8,and 10 weeks(5 rabbits at each time point every group)after operation.Results Lumbar spine bone marrow fat fraction(FF) in Group C was significantly increased over the time course of osteoporosis development with significant difference between Group C and Group A at 4,8,and 10 weeks after operation(P<0.01).BMD in Group C at 8 and 10 week points after OVX was significantly decreased compared to Group A(P<0.01).A moderate negative significant correlation between marrow fat content and bone microstructure parameters such as BMD(r=-0.69)、BV/TV(r=-0.75)、Tb.Th(r=-0.57)、Conn.D(r=-0.69)and Tb.N(r=-0.57) was found,which indicated a decline in bone quality as marrow fat content increased.While FF values positively correlated to SMI(r=0.62)and Tb.Sp(r=0.87)with significant difference.Conclusion MRS and Micro-CT scanning can invasively evaluate the bone marrow changes of OP in pathophysiology and microstructure,respectively.Combination of both modality may be valuable in the early,comprehensive assessment of bone quality and bone mass in osteoporosis.