The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory e...The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.展开更多
Evaluation of Renal vascular anatomical variations Using Multi-Detector Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) male and 98 (49.5%) females, and their ages rang...Evaluation of Renal vascular anatomical variations Using Multi-Detector Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) male and 98 (49.5%) females, and their ages ranged between (3 - 94) years. The types of Accessory renal arteries were 1.8% (7/24) upper pole, 1.8% (7/24) lower pole and 2.5% (10/24) hilus. In males, 4 upper pole, 4 lower pole and 7 hilus. In females, 3 upper pole, 3 lower pole and 3 hilus. The percentage of right accessory renal arteries is almost twice that of the left and more than twice the bilateral accessory arteries. Accessory renal artery is a common but a significant anatomical variant of the renal vascular system, due to their clinical importance. In our sample, the accessory renal artery presence was detected in 6% and displayed a greater variation on the right than the left side. Because this abnormality plays an important role in kidney transplantations, in radiological, vascular and urological interventions, a detailed presentation of accessory renal artery incidence was conducted, gathering from the literature a large number of relevant studies in order to create a classification according to population, gender, side and specimen. The study concluded that the renal arteries present a broad spectrum of variability in their morphological expression regarding their length, diameter and entrance to the kidney parenchyma, additional arteries’ morphological expression was higher in men than women. This is statistically not significant and variation in the right side was found greater frequency than the left side.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
Anatomical Variations of Renal Vascular in Patients Undergoing Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) males and 198 (49.5%) females, and their ages ranged betw...Anatomical Variations of Renal Vascular in Patients Undergoing Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) males and 198 (49.5%) females, and their ages ranged between (3 - 94) years. The study showed mean of total samples of the width and length of right and left kidneys respectively measurements were 5.354 ± 0.948 and 5.571 ± 0.966 for width and 10.028 ± 1.3684 and 10.060 ± 1.5203 for length, the width and length for right renal artery 5.746 ± 1.2814 and 5.881 ± 1.1444 respectively and for left renal artery 5.894 ± 1.3175 and 4.961 ± 1.3175 respectively. Accessory renal artery is a common but a significant anatomical variant of the renal vascular system, due to its clinical importance. In our sample, the accessory renal artery presence was detected in 6% and displayed a greater variation on the right than the left side. Because this abnormality plays an important role in kidney transplantations, in radiological, vascular and urological interventions, a detailed presentation of accessory renal artery incidence was conducted, gathering from the literature a large number of relevant studies in order to create a classification according to population, gender, side and specimen. And the study concluded that the renal arteries present a broad spectrum of variability in their morphological expression regarding their length, diameter and entrance to the kidney parenchyma. The inferior polar renal artery was found same as the superior polar renal artery, additional arteries’ morphological expression was higher in men than women. This is statistically not significant and variation in the right side was found greater frequency than the left side.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42277150,41977219)Henan Provincial Science and Technology Research Project(Grant No.222102320271).
文摘The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.
文摘Evaluation of Renal vascular anatomical variations Using Multi-Detector Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) male and 98 (49.5%) females, and their ages ranged between (3 - 94) years. The types of Accessory renal arteries were 1.8% (7/24) upper pole, 1.8% (7/24) lower pole and 2.5% (10/24) hilus. In males, 4 upper pole, 4 lower pole and 7 hilus. In females, 3 upper pole, 3 lower pole and 3 hilus. The percentage of right accessory renal arteries is almost twice that of the left and more than twice the bilateral accessory arteries. Accessory renal artery is a common but a significant anatomical variant of the renal vascular system, due to their clinical importance. In our sample, the accessory renal artery presence was detected in 6% and displayed a greater variation on the right than the left side. Because this abnormality plays an important role in kidney transplantations, in radiological, vascular and urological interventions, a detailed presentation of accessory renal artery incidence was conducted, gathering from the literature a large number of relevant studies in order to create a classification according to population, gender, side and specimen. The study concluded that the renal arteries present a broad spectrum of variability in their morphological expression regarding their length, diameter and entrance to the kidney parenchyma, additional arteries’ morphological expression was higher in men than women. This is statistically not significant and variation in the right side was found greater frequency than the left side.
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Anatomical Variations of Renal Vascular in Patients Undergoing Computerized Tomographic scan in Sudan, the total number of patients studied is 400, 202 (50.5%) males and 198 (49.5%) females, and their ages ranged between (3 - 94) years. The study showed mean of total samples of the width and length of right and left kidneys respectively measurements were 5.354 ± 0.948 and 5.571 ± 0.966 for width and 10.028 ± 1.3684 and 10.060 ± 1.5203 for length, the width and length for right renal artery 5.746 ± 1.2814 and 5.881 ± 1.1444 respectively and for left renal artery 5.894 ± 1.3175 and 4.961 ± 1.3175 respectively. Accessory renal artery is a common but a significant anatomical variant of the renal vascular system, due to its clinical importance. In our sample, the accessory renal artery presence was detected in 6% and displayed a greater variation on the right than the left side. Because this abnormality plays an important role in kidney transplantations, in radiological, vascular and urological interventions, a detailed presentation of accessory renal artery incidence was conducted, gathering from the literature a large number of relevant studies in order to create a classification according to population, gender, side and specimen. And the study concluded that the renal arteries present a broad spectrum of variability in their morphological expression regarding their length, diameter and entrance to the kidney parenchyma. The inferior polar renal artery was found same as the superior polar renal artery, additional arteries’ morphological expression was higher in men than women. This is statistically not significant and variation in the right side was found greater frequency than the left side.
