Long-term reproducibility optimization of an x-ray process for bone architectural evaluation during osteoporosis

Non-invasive and in vivo assessment of bone architectural changes at high r esolution is of considerable interest in osteoporosis. In this note, the us e of an x-ray acquisition system in the evaluation of the architectural qua lity of trabecular bone by radiographic texture analysis is optimized to ac hieve good long-term reproducibility. First, radiographic and digitization processes are modelled and defined. Procedures to make radiographs and thei r digital images are fixed. Then, measurements of the modulation transfer f unction (MTF) of the entire acquisition chain were completed. These measure ments provide an MTF in excess of 30% at a spatial frequency of 2.5 lp/mm. Also, results of a fractal texture analysis made on digital images of calca neus radiographs show a mean coefficient of variation of 2.07%. These data show that good long-term reproducibility can make the x-ray acquisition sys tem efficient for patient follow-up, or evaluation of treatment regimes for osteoporosis. Finally, it is shown that fractal texture parameters are sta tistically different in an osteoporotic population and in a control group. Therefore, this system should also be of medical interest.