AIM To analyze planning total hip arthroplasty(THA) with an additional anteroposterior hip view may increases the accuracy of preoperative planning in THA.METHODS We conducted prospective digital planning in 100 conse...AIM To analyze planning total hip arthroplasty(THA) with an additional anteroposterior hip view may increases the accuracy of preoperative planning in THA.METHODS We conducted prospective digital planning in 100 consecutive patients: 50 of these procedures were planned using pelvic overview only(first group), and the other 50 procedures were planned using pelvic overview plus antero-posterior(a.p.) hip view(second group). The planning and the procedure of each patient were performed exclusively by the senior surgeon. Fifty procedures with retrospective analogues planning were used as the control group(group zero). After the procedure, the planning was compared with the eventually implanted components(cup and stem). For statistic analysis the x^2 test was used for nominal variables and the t test was used for a comparison of continuous variables.RESULTS Preoperative planning with an additional a.p. hip view(second group) significantly increased the exact component correlation when compared to pelvic overview only(first group) for both the acetabular cup and the femoral stem(76% cup and 66% stem vs 54% cup and 32% stem). When considering planning ± 1 size, the accuracy in the second group was 96%(48 of 50 patients) for the cup and 94% for the stem(47 of 50patients). In the analogue control group(group zero), an exact correlation was observed in only 1/3 of the cases.CONCLUSION Digital THA planning performed by the operating surgeon and based on additional a.p. hip view significantly increases the correlation between preoperative planning and eventual implant sizes.展开更多
Inspired by total variation(TV), this paper represents a new iterative algorithm based on diagonal total variation(DTV) to address the computed tomography image reconstruction problem. To improve the quality of a reco...Inspired by total variation(TV), this paper represents a new iterative algorithm based on diagonal total variation(DTV) to address the computed tomography image reconstruction problem. To improve the quality of a reconstructed image, we used DTV to sparsely represent images when iterative convergence of the reconstructed algorithm with TV-constraint had no effect during the reconstruction process. To investigate our proposed algorithm, the numerical and experimental studies were performed, and rootmean-square error(RMSE) and structure similarity(SSIM)were used to evaluate the reconstructed image quality. The results demonstrated that the proposed method could effectively reduce noise, suppress artifacts, and reconstruct highquality image from incomplete projection data.展开更多
衍射光栅已在波导中得到广泛应用,能将光束或图像从耦入端传输并在预定位置耦合输出,不过在应用于诸如增强现实/虚拟现实等大视场角(field of view,FOV)、彩色光源时会存在FOV不匹配、视场缺失、出射不均匀等问题.故从这些物理问题出发...衍射光栅已在波导中得到广泛应用,能将光束或图像从耦入端传输并在预定位置耦合输出,不过在应用于诸如增强现实/虚拟现实等大视场角(field of view,FOV)、彩色光源时会存在FOV不匹配、视场缺失、出射不均匀等问题.故从这些物理问题出发,推导出衍射波导的FOV上限、视场完整的理论边界公式,在此基础上再分别针对单色波和复色波进行深入研究.得出单层衍射波导在常规高折射率n=1.75条件下,支持单色波FOV理论上限约48°,支持复色波颜色系数q=1.3的FOV理论上限26.4°,更大FOV就需要配置更高折射率和更小q值.视场完整性的边界条件表明,减小长波的最大衍射角和减薄波导厚度就能解决视场缺失的问题,实用最大衍射角一般不超过75°,波导层厚度根据FOV大小一般在0.5-1.0 mm之间.最后提出将各全内反射视场展开为光线追迹图的方法和瞳孔均摊接收各角度光能的分布函数,就此可求解光栅耦出区的最佳位置,并利用分布函数的倒数来约束投射光的角分布或者光栅效率的角分布,以在任意位置都能接收均匀出射视场:单色波导的均匀性从0.27提高到0.15,单光栅复色波导中长波均匀性从0.40提高到0.28.这些研究结果有助于解决衍射波导用于大FOV和复色光的难题.展开更多
文摘AIM To analyze planning total hip arthroplasty(THA) with an additional anteroposterior hip view may increases the accuracy of preoperative planning in THA.METHODS We conducted prospective digital planning in 100 consecutive patients: 50 of these procedures were planned using pelvic overview only(first group), and the other 50 procedures were planned using pelvic overview plus antero-posterior(a.p.) hip view(second group). The planning and the procedure of each patient were performed exclusively by the senior surgeon. Fifty procedures with retrospective analogues planning were used as the control group(group zero). After the procedure, the planning was compared with the eventually implanted components(cup and stem). For statistic analysis the x^2 test was used for nominal variables and the t test was used for a comparison of continuous variables.RESULTS Preoperative planning with an additional a.p. hip view(second group) significantly increased the exact component correlation when compared to pelvic overview only(first group) for both the acetabular cup and the femoral stem(76% cup and 66% stem vs 54% cup and 32% stem). When considering planning ± 1 size, the accuracy in the second group was 96%(48 of 50 patients) for the cup and 94% for the stem(47 of 50patients). In the analogue control group(group zero), an exact correlation was observed in only 1/3 of the cases.CONCLUSION Digital THA planning performed by the operating surgeon and based on additional a.p. hip view significantly increases the correlation between preoperative planning and eventual implant sizes.
基金supported in part by the National Natural Science Foundation of China(No.61401049)the Chongqing Foundation and Frontier Research Project(Nos.cstc2016jcyjA0473,cstc2013jcyjA0763)+3 种基金the Graduate Scientific Research and Innovation Foundation of Chongqing,China(No.CYB16044)the Strategic Industry Key Generic Technology Innovation Project of Chongqing(No.cstc2015zdcy-ztzxX0002)China Scholarship Councilthe Fundamental Research Funds for the Central Universities Nos.CDJZR14125501,106112016CDJXY120003,10611CDJXZ238826
文摘Inspired by total variation(TV), this paper represents a new iterative algorithm based on diagonal total variation(DTV) to address the computed tomography image reconstruction problem. To improve the quality of a reconstructed image, we used DTV to sparsely represent images when iterative convergence of the reconstructed algorithm with TV-constraint had no effect during the reconstruction process. To investigate our proposed algorithm, the numerical and experimental studies were performed, and rootmean-square error(RMSE) and structure similarity(SSIM)were used to evaluate the reconstructed image quality. The results demonstrated that the proposed method could effectively reduce noise, suppress artifacts, and reconstruct highquality image from incomplete projection data.
文摘衍射光栅已在波导中得到广泛应用,能将光束或图像从耦入端传输并在预定位置耦合输出,不过在应用于诸如增强现实/虚拟现实等大视场角(field of view,FOV)、彩色光源时会存在FOV不匹配、视场缺失、出射不均匀等问题.故从这些物理问题出发,推导出衍射波导的FOV上限、视场完整的理论边界公式,在此基础上再分别针对单色波和复色波进行深入研究.得出单层衍射波导在常规高折射率n=1.75条件下,支持单色波FOV理论上限约48°,支持复色波颜色系数q=1.3的FOV理论上限26.4°,更大FOV就需要配置更高折射率和更小q值.视场完整性的边界条件表明,减小长波的最大衍射角和减薄波导厚度就能解决视场缺失的问题,实用最大衍射角一般不超过75°,波导层厚度根据FOV大小一般在0.5-1.0 mm之间.最后提出将各全内反射视场展开为光线追迹图的方法和瞳孔均摊接收各角度光能的分布函数,就此可求解光栅耦出区的最佳位置,并利用分布函数的倒数来约束投射光的角分布或者光栅效率的角分布,以在任意位置都能接收均匀出射视场:单色波导的均匀性从0.27提高到0.15,单光栅复色波导中长波均匀性从0.40提高到0.28.这些研究结果有助于解决衍射波导用于大FOV和复色光的难题.
