IMAGING OF AVASCULAR NECROSIS OF FEMORAL HEAD IN SPONTANEOUS HYPERTENSIVE RATS AND ITS EXPERIMENTAL MODEL

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We originally aimed to obtain magnetic resonance images of avascular necrosis of femoral head in spontaneous hypertensive rats, however, we failed to image them due to too small size of them such as 2mm in a diameter. Therefore, we change our plan and tried to obtain 3 dimensional analysis of trabecular structure of the femoral heads in spontaneous hypertensive rats using micro computed tomography. We obtained some results for the trabecular structural analysis, but, unfortunately, they were not promising of further study. We, again, changed our plan and tried to perform in vivo three-dimensional analysis of trabecular structure of human vertebra using data from multi-detector CT. We successfully read image data of multi-detector CT using the software for three-dimensional analysis of trabecular structure built in the micro CT. We performed precision study for the three-dimensional analysis using vertebra of a human cadaver. We evaluated three dimensional parameters of bone volume (BV) , bone surface (BS), bone density (BV/TV), trabecular thickness (Tb. Th), trabecular space (Tb. Sp), trabecular bone factor (TBPf) , structure model index (SMI) , number of nodes (N. Nd). We measured the specimens five times and calculated coefficient variation (CV). The CVs in BV, BS, BV/TV, Tb. Th, Tb. Sp, TBPf, SMI, N. Nd were 1.8 %, 0.91 %, 1.8 %, 1.4 %, 1.5 %, 7.7 %, 0.81 %, 2.5 %, respectively. The results were comparable to the precision of bone densitometry by dual x-ray absorptiometry. This suggest that in vivo three dimensional analysis of trabecular bone structure would be used clinically for evaluating effects of drugs for osteoporosis on trabecular bone structure.