Bone mineral of osteoporotic animal models can be non-invasively determined using DXA and peripheral quantitative computed tomography (pQCT). DXA can precisely detect accelerated trabecular bone loss at different sites in ovariectomized (OVX) rats. Rat cortical bone may not mature until 7.5 months of age. Low calcium diet exerts a great potential and trabecular volumetric BMD. Histomorphometry is widely used in the assessment of 2D trabecular structure, dynamic parameters, and cellular activity. Considerable progress has been made in advanced imaging techniques, such as micro CT ( mu CT) and micro magnetic resonance imaigng ( mu MRI), for noninvasive and/or nondestructive assessment of trabeculae in OVX induced osteopenia and in various treatments in rats in vivo and in vitro. Using a small high-efficiency coil in high-field imager, mu MRI can be performed at resolutions sufficient to discriminate individual trabeculae, and is capable of demonstrating differences in rat trabeculae following OVX that are not detected by DXA. Though they are equipment and technique demanding, the advanced iamging methods are able to measure 3D structure and ocnnectivity in arbitrary orientations in a highly automated, objective, non-user-specific manner. They can have a large sample size and therefore less sampling error. They are no-destructive which allows multiple tests on the same sample. The most important aim of any therapy for osteoporosis is to improve biomechanical competence, as an increase in quantity of bone mineral is not necessarily followed by an increase in bone quality, such as treatment of low dose long-term sodium fluoride in OVX rats. Torsion of the long bones and compression of the vertebral body are among commonly used biomechanical testing methods.
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