Background The vertebral artery （VA） and atlantoaxial joint （AAJ）, with complicated structures, are located in the depths of the head-neck boundary area, the regional anatomy of which cannot be shown globally and ...Background The vertebral artery （VA） and atlantoaxial joint （AAJ）, with complicated structures, are located in the depths of the head-neck boundary area, the regional anatomy of which cannot be shown globally and directly. This study aims to evaluate three-dimensional CT angiography （3DCTA） in displaying the AAJ, atlantoaxial segment of the vertebral artery （ASVA） and the identification of their interrelations. Methods Sixty-eight subjects without pathology of the ASVA and AAJ were selected from head-neck CTA examination. All the 3D images were formed with volume rendering （VR） together with techniques of separating, fusing, opacifying and false-coloring （SFOF）. On the 3D images, the ASVA and AAJ were observed, and their interrelations were measured. Results All the 3DCTA images were of high quality and up to our requirements. They could clearly and directly show the ASVA, ascending along the AAJ. There were 5 curves in the course of the ASVA, of which 2 curves were away from the atlantoaxial joint, one in the 2rid curve of 0.0 mm-5.4 mm, the other in the 4th of 2.6 mm-9.2 mm. There was no significant difference in the measurements between left and right （P 〉0.05）. The curved parts of the ASVA slightly expanded, with the biggest diameter of 5.6 mm in the 4th curve. Statistical comparison shows that the left ASVA is larger than the right （P 〈0.05）. Variations of the ASVA were found in 8 cases and of the AAJ in 12. Conclusions 3DCTA can globally and directly demonstrate the structures of the AAJ, ASVA and their interrelations. The 3D imaging data make up and enrich the research contents of regional anatomy and lay the foundation for related study and applications.展开更多
In order to investigate the effects of two mineral admixtures （i. e., fly ash and ground slag）on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT（ micro-focus computer tomogra...In order to investigate the effects of two mineral admixtures （i. e., fly ash and ground slag）on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT（ micro-focus computer tomography）is employed to quantitatively analyze the initial defects in four series of highperformance concrete （HPC）specimens with additions of different mineral admixtures. The nigh-resolution 3D images of microstructures and filtered defects are reconstructed by micro- CT software. The size distribution and volume fractions of initial defects are analyzed based on 3D and 2D micro-CT images. The analysis results are verified by experimental results of watersuction tests. The results show that the additions of mineral admixtures in concrete as cementitious materials greatly change the geometrical properties of the microstructures and the spatial features of defects by physical-chemistry actions of these mineral admixtures. This is the major cause of the differences between the mechanical behaviors of HPC with and without mineral admixtures when the water-to-binder ratio and the size distribution of aggregates are constant.展开更多
Objective:To evaluate and compare the diagnosti c value in atlantoaxial subluxation by CT three-dimensional (3D) reconstruction . Methods:3D reconstruction findings of 41 patients with atlanto axial subluxation were r...Objective:To evaluate and compare the diagnosti c value in atlantoaxial subluxation by CT three-dimensional (3D) reconstruction . Methods:3D reconstruction findings of 41 patients with atlanto axial subluxation were retrospectively analyzed, and comparisons were made among images of transverse section, multiplanar reformorting (MPR), surface shade dis play (SSD), maximum intensity project (MIP), and volume rendering (VR). Results:Of 41 patients with atlantoaxial subluxation, 31 belon ged to rotary dislocation, 5 antedislocation, and 5 hind dislocation. All the ca ses showed the dislocated joint panel of atlantoaxial articulation. Fifteen case s showed deviation of the odontoid process and 8 cases widened distance between the dens and anterior arch of the atlas. The dislocated joint panel of atlantoax ial articulation was more clearly seen with SSD-3D imaging than any other metho ds. Conclusions:Atlantoaxial subluxation can well be diagnosed by CT 3D reconstruction, in which SSD-3D imaging is optimal.展开更多
文摘Background The vertebral artery （VA） and atlantoaxial joint （AAJ）, with complicated structures, are located in the depths of the head-neck boundary area, the regional anatomy of which cannot be shown globally and directly. This study aims to evaluate three-dimensional CT angiography （3DCTA） in displaying the AAJ, atlantoaxial segment of the vertebral artery （ASVA） and the identification of their interrelations. Methods Sixty-eight subjects without pathology of the ASVA and AAJ were selected from head-neck CTA examination. All the 3D images were formed with volume rendering （VR） together with techniques of separating, fusing, opacifying and false-coloring （SFOF）. On the 3D images, the ASVA and AAJ were observed, and their interrelations were measured. Results All the 3DCTA images were of high quality and up to our requirements. They could clearly and directly show the ASVA, ascending along the AAJ. There were 5 curves in the course of the ASVA, of which 2 curves were away from the atlantoaxial joint, one in the 2rid curve of 0.0 mm-5.4 mm, the other in the 4th of 2.6 mm-9.2 mm. There was no significant difference in the measurements between left and right （P 〉0.05）. The curved parts of the ASVA slightly expanded, with the biggest diameter of 5.6 mm in the 4th curve. Statistical comparison shows that the left ASVA is larger than the right （P 〈0.05）. Variations of the ASVA were found in 8 cases and of the AAJ in 12. Conclusions 3DCTA can globally and directly demonstrate the structures of the AAJ, ASVA and their interrelations. The 3D imaging data make up and enrich the research contents of regional anatomy and lay the foundation for related study and applications.
基金The Scholarship Supported by Ministry of Education of China for Research Abroad(No.3037[2006])the Excellent Doctoral Dissertation Foundation of Southeast University (No.YBTJ-0512)the National Basic Research Program of China(973Program)(No.2009CB623203)
文摘In order to investigate the effects of two mineral admixtures （i. e., fly ash and ground slag）on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT（ micro-focus computer tomography）is employed to quantitatively analyze the initial defects in four series of highperformance concrete （HPC）specimens with additions of different mineral admixtures. The nigh-resolution 3D images of microstructures and filtered defects are reconstructed by micro- CT software. The size distribution and volume fractions of initial defects are analyzed based on 3D and 2D micro-CT images. The analysis results are verified by experimental results of watersuction tests. The results show that the additions of mineral admixtures in concrete as cementitious materials greatly change the geometrical properties of the microstructures and the spatial features of defects by physical-chemistry actions of these mineral admixtures. This is the major cause of the differences between the mechanical behaviors of HPC with and without mineral admixtures when the water-to-binder ratio and the size distribution of aggregates are constant.
文摘Objective:To evaluate and compare the diagnosti c value in atlantoaxial subluxation by CT three-dimensional (3D) reconstruction . Methods:3D reconstruction findings of 41 patients with atlanto axial subluxation were retrospectively analyzed, and comparisons were made among images of transverse section, multiplanar reformorting (MPR), surface shade dis play (SSD), maximum intensity project (MIP), and volume rendering (VR). Results:Of 41 patients with atlantoaxial subluxation, 31 belon ged to rotary dislocation, 5 antedislocation, and 5 hind dislocation. All the ca ses showed the dislocated joint panel of atlantoaxial articulation. Fifteen case s showed deviation of the odontoid process and 8 cases widened distance between the dens and anterior arch of the atlas. The dislocated joint panel of atlantoax ial articulation was more clearly seen with SSD-3D imaging than any other metho ds. Conclusions:Atlantoaxial subluxation can well be diagnosed by CT 3D reconstruction, in which SSD-3D imaging is optimal.
