Objective: Physical loading changes bone microstructure and may influence quantitative ultrasound(QUS) parameters. This study aims at evaluating the effect of physical loading on bone QUS measurement. Methods: Ten fre...Objective: Physical loading changes bone microstructure and may influence quantitative ultrasound(QUS) parameters. This study aims at evaluating the effect of physical loading on bone QUS measurement. Methods: Ten fresh bovine bone specimens were studied, which were scanned by a micro-CT and the density and structure parameters were calculated. The QUS measurement was performed when specimens subjected to loading, which changed from 0 to 1,000 N with the step of 100 N. Statistical analysis was performed to evaluate the difference between n BUA measured with and without loading, and the relationship between n BUA and the parameters measured by micro-CT. Results: While the loading exerted on bone lugher than 200 N, the measured nBUA significantly higher than n BUA measured without loading. With the increasing of loading, which exerted on bone, the values of nBUA also increased. A new parameter, the slope of the linearity fitted curve of nBUA values measured under different loading conditions, was introduced to evaluate BMD. The correlation coefficient between the slope and BMD is-0.869(P=0.001). Conclusion: Physical loading substantially influences bone QUS measurement. QUS measurement performed under loading condition may be a new ultrasound method for osteoporosis diagnosis.展开更多
For a 3D C-arm computed tomography(CT) system, actual path of the scanner may deviate from the idea circle geometry because of mechanicalinstability,leading to perturbation artifacts in reconstructed images. In this p...For a 3D C-arm computed tomography(CT) system, actual path of the scanner may deviate from the idea circle geometry because of mechanicalinstability,leading to perturbation artifacts in reconstructed images. In this paper, we proposed a modified FBP method for the perturbed trajectories taking into account 6 perturbation parameters without tassuming any condition to be ideal. The preliminary studies demonstrated that this algorithm can acquire promising reconstruction image quality even when the perturbations are relatively large. The comparison of performances among different perturbation parameters is useful for constructing a C-arm CT system.展开更多
文摘Objective: Physical loading changes bone microstructure and may influence quantitative ultrasound(QUS) parameters. This study aims at evaluating the effect of physical loading on bone QUS measurement. Methods: Ten fresh bovine bone specimens were studied, which were scanned by a micro-CT and the density and structure parameters were calculated. The QUS measurement was performed when specimens subjected to loading, which changed from 0 to 1,000 N with the step of 100 N. Statistical analysis was performed to evaluate the difference between n BUA measured with and without loading, and the relationship between n BUA and the parameters measured by micro-CT. Results: While the loading exerted on bone lugher than 200 N, the measured nBUA significantly higher than n BUA measured without loading. With the increasing of loading, which exerted on bone, the values of nBUA also increased. A new parameter, the slope of the linearity fitted curve of nBUA values measured under different loading conditions, was introduced to evaluate BMD. The correlation coefficient between the slope and BMD is-0.869(P=0.001). Conclusion: Physical loading substantially influences bone QUS measurement. QUS measurement performed under loading condition may be a new ultrasound method for osteoporosis diagnosis.
基金Doctoral Program of Higher Education of Chinagrant number:20093218110024+1 种基金International Science and Technology Cooperation Grantgrant number:BZ2008060
文摘For a 3D C-arm computed tomography(CT) system, actual path of the scanner may deviate from the idea circle geometry because of mechanicalinstability,leading to perturbation artifacts in reconstructed images. In this paper, we proposed a modified FBP method for the perturbed trajectories taking into account 6 perturbation parameters without tassuming any condition to be ideal. The preliminary studies demonstrated that this algorithm can acquire promising reconstruction image quality even when the perturbations are relatively large. The comparison of performances among different perturbation parameters is useful for constructing a C-arm CT system.
