The use of computed microtomography to monitor morphological changes in small animals

Rationale and Objectives. We investigate the methodological aspects of computerised microtomography (CmT) for monitoring the development of osteoporosis in male Sprague-Dawley rats. Methods. 120 Rats were gastrectomized or sham operated. Femurs were prepared and tomograms with spatial resolutions of 5–500 mm were made. Bone diameters, bone areas and moments of inertia were determined from the tomograms. Optimal slice position and the need for spatial resolution for future in vivo applications were investigated. In order to minimise the absorbed dose to the specimen, a theoretical model for determination of optimal irradiation conditions is developed. Results. Gastrectomy caused dramatic changes in the bone architecture. The main features were vacuolisation of the bone and reduced amounts of compact bone. While the outer diameters of tubular bones were largely unaffected, their inner diameters were greatly increased following gastrectomy. Relative bone area and moment of inertia were greatly reduced. Optimal photon energy was 12 keV. Conclusions. It is possible to monitor gastrectomy-evoked changes in bone morphology at various sites in rats with computerised microtomography. The changes are suggestive of osteoporosis.