In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress ...In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.展开更多
Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scannin...Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scanning mode. Methods: The imaging data of 100 patients who underwent CT coronary angiography (CCTA) using Siemens force CT retrospective gated triggering spiral scan (RES-SPIRAL), adaptive prospective gated triggering sequence scan (SEQ) and prospective coarse pitch scan (TurboFlash) retrospectively was collected. The image quality was evaluated by objective and subjective methods. The effective radiation dose of patients was compared and analyzed, and the indications of the three scanning modes were analyzed. The application value of dual-source CT TurboFlash coarse pitch scanning in coronary artery imaging was evaluated. Results: The results showed that the left main coronary artery, the right coronary artery and their tertiary branches could be clearly displayed in the three groups of images: the left anterior descending branch, the left circumflex branch, and their three-level branches. There was no statistical difference in subjective image quality among the three groups of pictures (P > 0.05). There was no statistical difference in objective evaluation indexes, such as CT value, SNR, CNR and Noise among the three groups (P > 0.05). The patient radiation dose results showed that the effective radiation dose ED of RES-SPIRA scan was (9.22 ± 1.33) mSv. The dose of SEQ was (2.88 ± 2.47) mSv, and the dose of TurboFlash was (0.51 ± 0.16) mSv. There was significant difference in comparison of the three groups (P 0.05). RES-spiral scanning had the highest radiation dose and TurboFlash coarse pitch scanning (TurboFlash) had the lowest radiation dose. Conclusion: TurboFlash coarse pitch scanning is low in dosage, fast in speed and wide in adaptability. It is especially suitable for the elderly, children, coma and other patients who cannot cooperate with breath-holding examination, as well as for the screening and examination of coronary artery diseases in asymptomatic population. Undoubtedly, it is a worthy method of heart coronary artery examination.展开更多
目的：采用低千伏前瞻性心电门控大螺距（Flash spiral）扫描冠状动脉CTA成像，原始数据采用迭代重建，评价该扫描模式获得具有诊断价值图像质量的冠状动脉CTA的可行性。方法50例患者，体质量指数（body mass index BMI）＜30kg/m^2，...目的：采用低千伏前瞻性心电门控大螺距（Flash spiral）扫描冠状动脉CTA成像，原始数据采用迭代重建，评价该扫描模式获得具有诊断价值图像质量的冠状动脉CTA的可行性。方法50例患者，体质量指数（body mass index BMI）＜30kg/m^2，心率≤60次/min。冠状动脉CTA成像采用前瞻性心电门控Flash spiral模式采集。原始图像重建采用两种重建方式，分别为反投影滤过重建及迭代重建。图像质量评分采用4分法。结果平均有效辐射剂量为（0.85±0.37） mSv。迭代重建的图像噪声降低，与反投影滤过重建比较具有统计学差异，数值分别为（26.4±5.2）和（20.6±4.1）HU。迭代重建的图像质量评分（1.9±1.1）降低，与反投影滤过重建（2.2±1.0）比较差异具有统计学意义（P〈0.0001）。728段冠状动脉段，反投影滤过重建有61段，迭代重建有38段被评为4分（P=0.07）。BMI指数为24-30 kg/m^2的患者，迭代重建的可评价图像噪声低，血管段SNR和CNR均比FBP重建高，且具有统计学意义。结论对于选择性人群，前瞻性心电门控大螺距低千伏扫描模式联合原始数据迭代重建可以提供充足的冠状动脉CTA图像质量。展开更多
基金Supported by the New-Cooperation Project of Japan Ministry of Economy,Trade and Industry
文摘In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.
文摘Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scanning mode. Methods: The imaging data of 100 patients who underwent CT coronary angiography (CCTA) using Siemens force CT retrospective gated triggering spiral scan (RES-SPIRAL), adaptive prospective gated triggering sequence scan (SEQ) and prospective coarse pitch scan (TurboFlash) retrospectively was collected. The image quality was evaluated by objective and subjective methods. The effective radiation dose of patients was compared and analyzed, and the indications of the three scanning modes were analyzed. The application value of dual-source CT TurboFlash coarse pitch scanning in coronary artery imaging was evaluated. Results: The results showed that the left main coronary artery, the right coronary artery and their tertiary branches could be clearly displayed in the three groups of images: the left anterior descending branch, the left circumflex branch, and their three-level branches. There was no statistical difference in subjective image quality among the three groups of pictures (P > 0.05). There was no statistical difference in objective evaluation indexes, such as CT value, SNR, CNR and Noise among the three groups (P > 0.05). The patient radiation dose results showed that the effective radiation dose ED of RES-SPIRA scan was (9.22 ± 1.33) mSv. The dose of SEQ was (2.88 ± 2.47) mSv, and the dose of TurboFlash was (0.51 ± 0.16) mSv. There was significant difference in comparison of the three groups (P 0.05). RES-spiral scanning had the highest radiation dose and TurboFlash coarse pitch scanning (TurboFlash) had the lowest radiation dose. Conclusion: TurboFlash coarse pitch scanning is low in dosage, fast in speed and wide in adaptability. It is especially suitable for the elderly, children, coma and other patients who cannot cooperate with breath-holding examination, as well as for the screening and examination of coronary artery diseases in asymptomatic population. Undoubtedly, it is a worthy method of heart coronary artery examination.
文摘目的：采用低千伏前瞻性心电门控大螺距（Flash spiral）扫描冠状动脉CTA成像，原始数据采用迭代重建，评价该扫描模式获得具有诊断价值图像质量的冠状动脉CTA的可行性。方法50例患者，体质量指数（body mass index BMI）＜30kg/m^2，心率≤60次/min。冠状动脉CTA成像采用前瞻性心电门控Flash spiral模式采集。原始图像重建采用两种重建方式，分别为反投影滤过重建及迭代重建。图像质量评分采用4分法。结果平均有效辐射剂量为（0.85±0.37） mSv。迭代重建的图像噪声降低，与反投影滤过重建比较具有统计学差异，数值分别为（26.4±5.2）和（20.6±4.1）HU。迭代重建的图像质量评分（1.9±1.1）降低，与反投影滤过重建（2.2±1.0）比较差异具有统计学意义（P〈0.0001）。728段冠状动脉段，反投影滤过重建有61段，迭代重建有38段被评为4分（P=0.07）。BMI指数为24-30 kg/m^2的患者，迭代重建的可评价图像噪声低，血管段SNR和CNR均比FBP重建高，且具有统计学意义。结论对于选择性人群，前瞻性心电门控大螺距低千伏扫描模式联合原始数据迭代重建可以提供充足的冠状动脉CTA图像质量。
