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Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry
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作者 Yingxian Lang Zhengzhao Liang Zhuo Dong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1348-1361,共14页
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
关键词 X-ray computerized tomography(ct)scanning PHOTOGRAMMETRY Parallel computing Numerical simulation Uniaxial compression test Digital image processing
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Influence of pore structure heterogeneity on channeling channels during hot water flooding in heavy oil reservoir based on CT scanning
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作者 Qing-Jun Du Hao-Yu Zheng +3 位作者 Jian Hou Yong-Ge Liu Jian-Fang Sun Dong Zhao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第4期2407-2419,共13页
Hot water flooding is an effective way to develop heavy oil reservoirs.However,local channeling channels may form,possibly leading to a low thermal utilization efficiency and high water cut in the reservoir.The pore s... Hot water flooding is an effective way to develop heavy oil reservoirs.However,local channeling channels may form,possibly leading to a low thermal utilization efficiency and high water cut in the reservoir.The pore structure heterogeneity is an important factor in forming these channels.This study proposes a method that mixes quartz sand with different particle sizes to prepare weakly heterogeneous and strongly heterogeneous models through which hot water flooding experiments are conducted.During the experiments,computer tomography(CT)scanning identifies the pore structure and micro remaining oil saturation distribution to analyze the influence of the pore structure heterogeneity on the channeling channels.The oil saturation reduction and average pore size are divided into three levels to quantitatively describe the relationship between the channeling channel distribution and pore structure heterogeneity.The zone where oil saturation reduction exceeds 20%is defined as a channeling channel.The scanning area is divided into 180 equally sized zones based on the CT scanning images,and threedimensional(3D)distributions of the channeling channels are developed.Four micro remaining oil distribution patterns are proposed,and the morphology characteristics of micro remaining oil inside and outside the channeling channels are analyzed.The results show that hot water flooding is more balanced in the weakly heterogeneous model,and the oil saturation decreases by more than 20%in most zones without narrow channeling channels forming.In the strongly heterogeneous model,hot water flooding is unbalanced,and three narrow channeling channels of different lengths form.In the weakly heterogeneous model,the oil saturation reduction is greater in zones with larger pores.The distribution range of the average pore size is larger in the strongly heterogeneous model.The network remaining oil inside the channeling channels is less than outside the channeling channels,and the hot water converts the network remaining oil into cluster,film,and droplet remaining oil. 展开更多
关键词 Heavy oil Hot water flooding Pore structure Channeling channels ct scanning
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Fatigue properties and damage constitutive model of salt rock based on CT scanning
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作者 Junbao Wang Xiao Liu +3 位作者 Qiang Zhang Xinrong Liu Zhanping Song Shijin Feng 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第2期245-259,共15页
To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,an... To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading. 展开更多
关键词 Salt rock Cyclic loading ct scanning Mesoscopic pore evolution Constitutive model
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Phase II Clinical Study of Three-Dimensional Printed Coplanar Template Combined with CT-Guided Percutaneous Core Needle Biopsy of Pulmonary Nodules in Elderly Patients
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作者 Wangti Xie Yu Wu +11 位作者 Xiaoshan Cheng Jianbing Hu Fang Wen Jia Xiao Pan Luo Yuqi Su Xiang Yao Jianlong Fang Grong Dan Xianggan Huang Dunqian Liu Jie Weng 《Journal of Biosciences and Medicines》 2024年第7期325-336,共12页
Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lu... Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lung, brain and blood vessels and cannot tolerate surgery. Computed tomography (CT)-guided percutaneous core needle biopsy (CNB) was the first choice for pathological diagnosis and subsequent targeted drugs, immune drugs or ablation treatment. CT-guided percutaneous CNB requires clinicians with rich CNB experience to ensure high CNB accuracy, but it was easy to cause complications such as pneumothorax and hemorrhage. Three-dimensional (3D) printing coplanar template (PCT) combined with CT-guided percutaneous pulmonary CNB biopsy has been used in clinical practice, but there was no prospective, randomized controlled study. Methods: Elderly patients with lung nodules admitted to the Department of Oncology of our hospital from January 2019 to January 2023 were selected. A total of 225 elderly patients were screened, and 30 patients were included after screening. They were randomly divided into experimental group (Group A: 30 cases) and control group (Group B: 30 cases). Group A was given 3D-PCT combined with CT-guided percutaneous pulmonary CNB biopsy, Group B underwent CT-guided percutaneous pulmonary CNB. The primary outcome measure of this study was the accuracy of diagnostic CNB, and the secondary outcome measures were CNB time, number of CNB needles, number of pathological tissues and complications. Results: The diagnostic accuracy of group A and group B was 96.67% and 76.67%, respectively (P = 0.026). There were statistical differences between group A and group B in average CNB time (P = 0.001), number of CNB (1 vs more than 1, P = 0.029), and pathological tissue obtained by CNB (3 vs 1, P = 0.040). There was no statistical difference in the incidence of pneumothorax and hemorrhage between the two groups (P > 0.05). Conclusions: 3D-PCT combined with CT-guided percutaneous CNB can improve the puncture accuracy of elderly patients, shorten the puncture time, reduce the number of punctures, and increase the amount of puncture pathological tissue, without increasing pneumothorax and hemorrhage complications. We look forward to verifying this in a phase III randomized controlled clinical study. . 展开更多
关键词 Pulmonary Nodules Elderly patients three-dimensional (3D) Printed Coplanar Template (Pct) Core Needle Biopsy (CNB) Computed Tomography (ct)
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Surface characteristics analysis of fractures induced by supercritical CO_(2)and water through three-dimensional scanning and scanning electron micrography 被引量:7
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作者 Hao Chen Yi Hu +4 位作者 Jiawei Liu Feng Liu Zheng Liu Yong Kang Xiaochuan Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2021年第5期1047-1058,共12页
Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyze... Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance. 展开更多
关键词 Supercritical carbon dioxide(SC-CO_(2))fracturing Quantitative characterization of surface features Surface roughness and fractal dimension three-dimensional(3D)scanning scanning electron micrograph(SEM)
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Application of Three-dimensional Laser Scanning Technology in the Teaching Practice of Surveying and Mapping of Ancient Buildings
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作者 Yapeng DUAN Junli LIU +2 位作者 Zhendong LIU Dingtao CAI Shaomin NI 《Asian Agricultural Research》 2019年第11期77-80,共4页
Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser sca... Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser scanning technology.Based on the practical application,this paper puts forward the discussion of related problems and matters needing attention.This has a certain reference significance for the study of new technology in surveying and mapping of ancient buildings. 展开更多
关键词 three-dimensional laser scanning technology SURVEYING and MAPPING of ANCIENT BUILDINGS
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Integration system research and development for three-dimensional laser scanning information visualization in goaf 被引量:1
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作者 罗周全 黄俊杰 +2 位作者 罗贞焱 汪伟 秦亚光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1985-1994,共10页
An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo... An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable. 展开更多
关键词 GOAF laser scanning visualization integration system 1 Introduction The goaf formed through underground mining of mineral resources is one of the main disaster sources threatening mine safety production [1 2]. Effective implementation of goaf detection and accurate acquisition of its spatial characteristics including the three-dimensional morphology the spatial position as well as the actual boundary and volume are important basis to analyze predict and control disasters caused by goaf. In recent years three-dimensional laser scanning technology has been effectively applied in goaf detection [3 4]. Large quantities of point cloud data that are acquired for goaf by means of the three-dimensional laser scanning system are processed relying on relevant engineering software to generate a three-dimensional model for goaf. Then a general modeling analysis and processing instrument are introduced to perform subsequent three-dimensional analysis and calculation [5 6]. Moreover related development is also carried out in fields such as three-dimensional detection and visualization of hazardous goaf detection and analysis of unstable failures in goaf extraction boundary acquisition in stope visualized computation of damage index aided design for pillar recovery and three-dimensional detection
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Hemangioblastoma Incidentally Discovered at CT Scan in Bamako: About a Case
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作者 Traore Ousmane N’Diaye Mamadou +5 位作者 Dembélé Mamadou Dembélé Adama Diakité Siaka Sidibé Mansa Drissa Camara Nagnoumague Keita Adama Diaman 《Open Journal of Medical Imaging》 2024年第3期123-127,共5页
Hemangioblastomas are benign vascular tumors of the brain. These are rare tumors, usually located in the cerebellum and most often affecting young adults. The aim was to study the value of CT in the management of hema... Hemangioblastomas are benign vascular tumors of the brain. These are rare tumors, usually located in the cerebellum and most often affecting young adults. The aim was to study the value of CT in the management of hemangioblastoma through observation. We report the case of a 38-year-old patient referred to the radiology and Medical Imaging Department of the Marie Curie Medical Clinic in Bamako, Mali, for an orbito-cerebral CT scan in a context of bilateral eyelid edema. The examination was performed using multi-slice computed tomography (16 slices) with reconstruction in the 3 planes of space without and with the injection of an iodinated contrast agent. The CT scan was crucial in making the diagnosis of hemangioblastoma incidentally, which allowed for adequate management. The patient was operated on, and the radiological outcome was favorable, without significant cystic formation, after postoperative control and clinical signs were resolved. CT can be an interesting alternative in countries like ours despite MRI being the examination of choice in hemangioblastomas. 展开更多
关键词 HEMANGIOBLASTOMA ct scan Incidental Discovery and Bamako
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Diameters and form of skull base foramen ovale measured by three-dimensional spiral CT thin-slice scan in healthy adults
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作者 Xiaohua Chen Fengxian Deng +1 位作者 Shuhang Wei Tingsong Fang 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第4期343-346,共4页
BACKGROUND: The accurate measurements of various data of the bone diameters of foramen ovale of living person can change the methods of puncturing trigeminal gasserian ganglion via foramen ovale for treating trifacia... BACKGROUND: The accurate measurements of various data of the bone diameters of foramen ovale of living person can change the methods of puncturing trigeminal gasserian ganglion via foramen ovale for treating trifacial neuralgia from the experience of puncture operator only to puncture by taking the objective data of measurement as the evidence, which is good for improving the accuracy of puncturing trigeminal ganglion and reducing side effects. OBJECTIVE : To observe the forms of foramen ovales in healthy adults displayed by volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan of skull base, and measure the longitudinal diameter and transverse diameter. DESIGN : A repetitive observation and measurement SETTINGS : Department of Neurosurgery and Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine. PARTICIPANTS: Fifty healthy adults (100 sides), who were examined with three-dimensional spiral CT scan, were randomly selected from the Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine from January 2005 to January 2006, including 26 males and 24 females, aged 25-68 years with an average of 48 years old. They were all informed and agreed with the examination. METHODS : The subjects were examined with the Philips 16-slice spiral CT-Mx 8000 IDT CT apparatus (Philips Company, Holland), the scanning ranged from 2 cm below the canthomeatal line to the level of suprasellar cistem. The width of collimator was 0.75 mm, pitch was 0.663; tube current was 350 mA, voltage was 120 kV, resolution was 512×512 matrix; slice thickness of reconstruction was 1 mm, and interval was 0.5 mm. After the three-dimensional spiral CT thin-slice scan of skull base, the image post-processing techniques including volume rendering and multi-planar reconstruction were applied to observe the forms of foramen ovales, and measure the size, longitudinal diameter and transverse diameter of the foramen ovales. The figures of the foramen ovales were drawn with mouse along the boundary of bone porous margin and soft tissue. According to the indications, the diameters were measured with computer to observe the forms of foramen ovales. MAIN OUTCOME MEASURES : The longitudinal diameter, transverse diameter and form of foramen ovales were observed. RESULTS: All the 50 healthy adults (100 sides) were involved in the analysis of results. (1) It was observed in the volume rendering images that foramen ovales had four forms of oval shape (77 sides), kidney shape (12 sides), round shape (7 sides), ribbon shape (4 sides). (2) The longitudinal diameters of left and right foramen ovales were (7.67±1.32) and (7.98±1.45) mm, and the transverse diameters were (4.04±0.83), (4.09±1.07) mm; There was no obvious difference between left and right longitudinal diameters (t = 1.63, P = 0.11 ), and left and right transverse diameters were close (t = 0.45, P= 0.65). CONCLUSION : The non-invasive techniques of volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan can clearly display the formand size of foramen ovale in healthy adults. 展开更多
关键词 Diameters and form of skull base foramen ovale measured by three-dimensional spiral ct thin-slice scan in healthy adults ct base
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Three-dimensional Imaging of Multi-slice Spiral CT in Bronchial Artery Correlative Study on Blood Supply of Central Lung Cancer and Its Clinical Significance 被引量:4
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作者 李智勇 杨冬 +2 位作者 伍建林 黎庶 董天 《The Chinese-German Journal of Clinical Oncology》 CAS 2005年第1期40-42,67,共4页
Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention t... Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention therapy. Methods: Eighteen patients with central lungcancer underwent MSCT with real time helical thin-slice CT scanning. Three-dimensional bronchialartery reconstruction was done at the console work-station. The space anatomical characters ofbronchial artery were observed through different rotations. Results: For 6 cases, thethree-dimensional images of bronchial artery (33.33%) could exactly show the origins, the routes(lung inner segment and mediatism segment) and the diameters of bronchial arteries. Vision rate ofbronchial arteries was the highest in pulmonary artery stricture and truncation groups, and thevessels' diameter became larger apparently. These characters demonstrated blood supply of this kindof central lung cancer come from bronchial artery. Volume rendering images were the best ones amongthree-dimensional images. Conclusion: Three-dimensional imaging with MSCT in bronchial artery canreveal the anatomical characters of bronchial artery and provide theoretical evidence on bloodsupply and intervention therapy of central lung cancer. 展开更多
关键词 bronchial artery multi-slice spiral ct three-dimensional reconstruction ANGIOGRAPHY
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基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究 被引量:1
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作者 刘瑾 车文越 +6 位作者 郝社锋 马晓凡 喻永祥 王颖 陈志昊 李婉婉 钱卫 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第5期1119-1126,共8页
干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效... 干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效提高土体的抗压强度和耐干湿循环效果。随着黄原胶含量的增加,干湿循环作用后的强度损失逐渐减小,当循环次数从0次增加到4次时,对于加入黄原胶含量分别为0%,0.5%,1.5%的试样,抗压强度分别损失了42.75%,17.2%,14.04%。(2)加固土的抗压强度与干湿循环次数之间保持指数下降的关系,当循环次数达到4次后,随着循环次数的进一步增加,抗压强度和弹性模量均在较小的变化范围内波动。(3)随着干湿循环次数的增加,黄原胶加固土的孔隙率表现出先增加后减小的趋势,连通孔隙不断扩展,而孤立孔隙表现出先增加后减小的趋势。(4)随着试样的干燥,黄原胶在土颗粒间形成网状基质,提高土体的强度和耐干湿循环能力。 展开更多
关键词 生物聚合物 黄原胶 抗压强度 ct扫描 微观结构 劣化机制
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基于深度学习的煤岩Micro-CT裂隙智能提取与应用
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作者 王登科 房禹 +8 位作者 魏建平 张宏图 赵立桢 王龙航 夏缘帝 李璐 王少璞 张强 任海慧 《煤炭学报》 EI CAS CSCD 北大核心 2024年第8期3439-3452,共14页
为解决煤岩CT裂隙图像识别中矸石影响以及不同尺度裂隙识别的问题,设计并实现了一种基于深度学习的煤岩裂隙提取网络模型(MCSN),该模型基于U-Net网络,利用其编码器-解码器结构和跳跃连接,可实现从复杂煤岩体中分割出完整的裂隙结构图像... 为解决煤岩CT裂隙图像识别中矸石影响以及不同尺度裂隙识别的问题,设计并实现了一种基于深度学习的煤岩裂隙提取网络模型(MCSN),该模型基于U-Net网络,利用其编码器-解码器结构和跳跃连接,可实现从复杂煤岩体中分割出完整的裂隙结构图像。首先,通过煤岩工业CT扫描系统获取煤岩体内部扫描图片后,人工标注出CT图像中的裂隙结构,并利用数据增强扩充标注的原始数据制作出煤岩CT裂隙数据集;然后,将训练好的VGG16模型权重通过迁移学习技术移至U-Net编码器部分,使得整个主干特征提取网络具有更强的裂隙结构特征提取能力;同时采用深度可分离空洞卷积模块(DCAC)和残差模块对U-Net模型中解码器部分进行改进,有效提升了CT图像中裂隙结构的识别能力,展现出了优越的分割精度和鲁棒性。为验证提出的煤岩裂隙提取网络模型的有效性,将MCSN的提取结果与经典的卷积神经网络及阈值分割方法的结果进行了对比,实验对比结果显示,提出的模型在定性分析和定量分析方面优势明显。这种多尺度融合的策略可以有效提取出复杂煤岩体图像中的裂隙,提高了裂隙识别效率和精度。将该模型应用到巷道围岩钻孔裂隙识别中,通过对钻孔成像仪采集到的窥孔视频和平面展开图进行裂隙提取,并结合二者提取结果进行交叉验证,得到了精准的巷道围岩裂隙分布范围,给出了穿层抽采钻孔的注浆封孔范围,提高了煤层瓦斯抽采体积分数。 展开更多
关键词 裂隙识别与提取 ct扫描 深度学习 卷积神经网络 空洞卷积
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基于CT断层扫描的木质家具与原木内部缺损三维可视化研究
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作者 赵桂玲 邓宗极 +1 位作者 藏加宇 邱兆文 《林产工业》 北大核心 2024年第2期24-28,共5页
研究木质家具与原木试件内部缺损三维可视化,有助于木质文物精准干预性保护与木材高效规划利用。凸显三维成像技术可视化优势,对木质文物保护具有重要意义。本文采用philips16排CT——A机型Brilliace16对试件三维断层扫描。通过对CT扫... 研究木质家具与原木试件内部缺损三维可视化,有助于木质文物精准干预性保护与木材高效规划利用。凸显三维成像技术可视化优势,对木质文物保护具有重要意义。本文采用philips16排CT——A机型Brilliace16对试件三维断层扫描。通过对CT扫描后原始图像的分割,获取品质较佳的三维数字模型。继而对分割后的图像进行切面与断面两个维度的手工着色,随后通过三维重建可得到开裂、虫洞、朽坏等不同形式缺损的三维形态,并可得到与之对应的精准三维模型。试验证明:通过三维重建,可获取木质试件内部不同类型三维缺损形态的可视化分析,可对缺损形态进行360°观察,并可获取三维缺损形态的表面积、体积等精准物理参数。本技术可为木质文物修复提供三维缺损形态的精准参数及直观可视化三维模型。 展开更多
关键词 木质品 ct扫描 着色 可视化分析 内部缺损体积
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CT增强扫描灰度直方图纹理分析技术对肺癌患者术前恶性程度评估及对预后的预测价值
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作者 毛宇 黎明 +3 位作者 乔文婷 郭剑峰 李容波 白艳艳 《中国CT和MRI杂志》 2024年第5期79-82,共4页
目的探究CT增强扫描灰度直方图纹理分析技术对肺癌患者术前恶性程度评估及对预后的预测价值。方法选择2018年5月至2022年9月在我院就诊的且经术后病理证实的肺癌患者580例作为研究对象。依据术后病理分期,将研究对象分为高分化组(183例... 目的探究CT增强扫描灰度直方图纹理分析技术对肺癌患者术前恶性程度评估及对预后的预测价值。方法选择2018年5月至2022年9月在我院就诊的且经术后病理证实的肺癌患者580例作为研究对象。依据术后病理分期,将研究对象分为高分化组(183例)、中分化组(195例)、低分化组(202例)。根据预后情况,将其分为预后良好组(356例)和预后不良组(224例)。由2名医师提取患者CT增强扫描灰度直方图纹理参数。受试者工作特征(receiver operating characteristic,ROC)曲线分析特征参数对肺癌患者术前恶性程度的诊断效能及预后的预测价值。多因素Logistic回归分析预后不良的重要影响因素并构建人工神经网络模型。Pearson分析检验参数间的相关性。结果均值、10%分位、50%分位等参数在高、中、低分化三组中有显著差异。三个参数对评估肺癌患者恶性程度均具有一定的诊断效能,且三者联合诊断效能最佳。均值、10%分位、50%分位是预后不良的保护因素,三者联合预测肺癌患者的曲线AUC值大于各指标单独预测的AUC值。ROC曲线和累积增益图表明该模型预测能力良好。纹理特征参数中,69.44%的参数具有相关性。结论CT增强扫描灰度直方图纹理参数在一定程度上反应肺癌患者术前恶性程度信息,给术前预测以及预后提供了重要方法。 展开更多
关键词 肺癌 ct增强扫描 灰度直方图 纹理分析
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基于CT扫描受压注浆体试块三维孔裂隙结构参数表征
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作者 朱昌星 吴大志 +1 位作者 王凤娥 孙家鑫 《河南理工大学学报(自然科学版)》 CAS 北大核心 2024年第3期42-49,共8页
目的为研究注浆体试块单轴压缩过程中孔裂隙结构演化特征,方法以级配砂砾注浆体试块为研究对象,对其单轴压缩过程分阶段进行工业CT扫描,并采用AVIZO对CT切片进行分析,重构孔裂隙结构三维模型,定量表征孔裂隙与孔喉特征参数。结果结果表... 目的为研究注浆体试块单轴压缩过程中孔裂隙结构演化特征,方法以级配砂砾注浆体试块为研究对象,对其单轴压缩过程分阶段进行工业CT扫描,并采用AVIZO对CT切片进行分析,重构孔裂隙结构三维模型,定量表征孔裂隙与孔喉特征参数。结果结果表明:单轴压缩下,试块依次经历孔裂隙萌生、发育、扩展与贯通阶段,孔裂隙演化特征比较明显,萌生阶段孔隙数增幅为14.41%,无明显贯通;发育阶段孔隙数增加326.91%,伴有一定数目孔隙贯通;扩展阶段孔隙数减少了57.79%,孔隙等效直径最大值增幅为223.45%,大部分孔隙贯通为裂隙;贯通阶段孔裂隙数目几乎不变,孔隙等效直径最大值增幅为92.83%,裂隙贯通后形成多个破裂面。峰值后试块出现连通孔隙,该阶段注浆体孔隙与喉道发育完全,试块破坏。结论研究结果可为后续破碎岩石注浆工程实践提供参考。 展开更多
关键词 ct扫描 注浆体 三维重构 孔裂隙结构 孔喉模型
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左心耳CT血管造影双期扫描在房颤患者中诊断左心耳血栓的应用价值
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作者 祁冬 姚传顺 +2 位作者 姚木子 贾媛 胡淑敏 《包头医学院学报》 CAS 2024年第2期62-66,共5页
目的:探讨左心耳CT血管造影(CTA)双期扫描在房颤患者中诊断左心耳血栓的应用价值。方法:回顾性收集2020年1月至2022年6月房颤患者36例,所有患者均行左心耳(LAA)CTA双期扫描和经食管超声心动图(TEE)检查。以TEE检查结果为“金标准”,分... 目的:探讨左心耳CT血管造影(CTA)双期扫描在房颤患者中诊断左心耳血栓的应用价值。方法:回顾性收集2020年1月至2022年6月房颤患者36例,所有患者均行左心耳(LAA)CTA双期扫描和经食管超声心动图(TEE)检查。以TEE检查结果为“金标准”,分别计算LAA-CTA第一期和第二期诊断LAA血栓的敏感性、特异性、阳性预测值、阴性预测值及诊断符合率,并采用Kappa检验评价LAA-CTA第一期和第二期诊断结果与TTE诊断结果的一致性。结果:LAA-CTA第一期诊断左心耳血栓患者21例,第二期诊断左心耳血栓患者15例,TTE诊断左心耳血栓患者14例;LAA-CTA第一期诊断LAA血栓的敏感性、特异性、阳性预测值、阴性预测值及诊断符合率分别为64.29%、45.45%、42.86%、66.67%及52.78%;LAA-CTA第二期诊断LAA血栓的敏感性、特异性、阳性预测值、阴性预测值及诊断符合率分别为92.86%、90.91%、86.67%、95.24%、91.67%,差异均有统计学意义(P<0.05)。LAA-CTA第一期诊断左心耳血栓结果与TEE诊断结果一致性一般(Kappa=0.089),而LAA-CTA第二期诊断左心耳血栓结果与TEE诊断结果一致性较好(Kappa=0.827),差异有统计学意义(P<0.05)。结论:左心耳CTA双期扫描均能发现LAA血栓,但第二期扫描诊断血栓的敏感性、特异性及诊断符合率均升高,且第二期诊断血栓结果与TEE一致性较好,因此左心耳CTA双期扫描方法在诊断LAA血栓方面具有较高的临床应用价值。 展开更多
关键词 左心耳 ct血管造影 双期扫描 心房颤动 血栓
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CT增强检查中碘对比剂外渗病人皮肤损伤风险预测模型的构建
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作者 梁俊丽 黄红芳 +2 位作者 陈秀珍 潘锡屏 施黎黎 《护理研究》 北大核心 2024年第18期3344-3348,共5页
目的:探讨CT增强检查中碘对比剂外渗病人皮肤损伤发生风险的影响因素,构建并验证风险预测模型。方法:采用便利抽样法抽取2023年1月—7月在广西医科大学第一附属医院放射科接受CT增强检查的碘对比剂外渗病人286例作为研究对象,自制CT增... 目的:探讨CT增强检查中碘对比剂外渗病人皮肤损伤发生风险的影响因素,构建并验证风险预测模型。方法:采用便利抽样法抽取2023年1月—7月在广西医科大学第一附属医院放射科接受CT增强检查的碘对比剂外渗病人286例作为研究对象,自制CT增强检查碘对比剂外渗病人皮肤损伤风险调查问卷对病人进行调查,采用单因素分析、Logistic回归分析筛选CT增强检查中碘对比剂外渗病人皮肤损伤发生风险的影响因素,构建风险预测模型,绘制列线图,运用受试者工作特征(ROC)曲线、校准曲线评价模型。结果:CT增强检查中碘对比剂外渗病人皮肤损伤发生率为18.5%。Logistic回归分析结果显示,过敏史、碘对比剂黏稠度、碘对比剂注射速度是CT增强检查中碘对比剂外渗病人皮肤损伤的影响因素(P<0.05),基于上述结果构建的预测模型建模组ROC曲线下面积为0.842[95%CI(0.770,0.915)],约登指数为0.667,最优截断值灵敏度为0.893,特异度为0.774;验证组ROC曲线下面积为0.924[95%CI(0.872,0.975)],约登指数为0.793,最优截断值灵敏度为0.891,特异度为0.902。Hosmer-Lemeshow检验结果显示,χ2=9.566,P=0.221 5,校准曲线与参考线相接近。结论:CT增强检查中碘对比剂外渗病人皮肤损伤风险预测模型预测效能良好,可为医务人员制订个性化的预防措施提供参考。 展开更多
关键词 ct增强扫描 碘对比剂 外渗 皮肤损伤 风险预测模型 影响因素 列线图 护理
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CT常规扫描与CT小肠造影对小肠肿瘤的诊断价值比较
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作者 罗建华 朱侣明 +3 位作者 陈圣文 邱秦文 谢鑫 杨娇君 《中国当代医药》 CAS 2024年第9期36-39,共4页
目的分析CT常规扫描与CT小肠造影对小肠肿瘤的诊断价值。方法选取2019年11月至2021年10月赣南医学院兴国医院的35例疑似小肠肿瘤患者作为研究对象,以病理检查结果为金标准,比较128层螺旋CT常规扫描与128层螺旋CT小肠造影诊断小肠肿瘤的... 目的分析CT常规扫描与CT小肠造影对小肠肿瘤的诊断价值。方法选取2019年11月至2021年10月赣南医学院兴国医院的35例疑似小肠肿瘤患者作为研究对象,以病理检查结果为金标准,比较128层螺旋CT常规扫描与128层螺旋CT小肠造影诊断小肠肿瘤的准确度、敏感度、特异度、阳性预测值、阴性预测值,并对比两种检查方式对各类型小肠肿瘤疾病的检出率。结果病理检查结果显示,35例疑似小肠肿瘤疾病患者中,阳性32例,阴性3例。32例阳性患者中,小肠脂肪瘤15例,小肠平滑肌瘤12例,腺瘤5例。CT小肠造影对小肠肿瘤疾病的诊断准确度为94.29%、敏感度为96.88%,CT常规扫描的诊断准确度为71.43%,敏感度为75.00%,CT小肠造影高于CT常规扫描,差异有统计学意义(P<0.05);CT小肠造影对小肠肿瘤疾病诊断的特异度为100.00%,阳性预测值为96.88%,阴性预测值为66.67%,CT常规扫描特异度为50.00%,阳性预测值为88.89%,阴性预测值为12.50%,两种检查方式比较差异无统计学意义(P>0.05)。两种检查方式对各类型小肠肿瘤疾病的检出率比较,差异无统计学意义(P>0.05)。结论对于小肠肿瘤患者,与CT常规扫描相比,CT小肠造影检查准确度、敏感度更高,诊断效能显著。 展开更多
关键词 ct常规扫描 ct小肠造影 小肠肿瘤 准确度 敏感度
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512层螺旋CT薄层扫描结合计算机人工神经网络对小肠病变的诊断价值研究
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作者 廖忠剑 文兴林 +3 位作者 刘艳平 邓星星 范存庚 雷剑 《医学理论与实践》 2024年第9期1458-1461,1470,共5页
目的:运用图像识别和图像描述技术,研究512层螺旋CT薄层扫描结合计算机人工神经网络在小肠病变诊断上的应用价值。方法:建立基于ResNet 101、Faster R-CNN、LSTM的小肠CT图像识别描述人工神经网络模型,采用ResNet 101和Faster R-CNN联... 目的:运用图像识别和图像描述技术,研究512层螺旋CT薄层扫描结合计算机人工神经网络在小肠病变诊断上的应用价值。方法:建立基于ResNet 101、Faster R-CNN、LSTM的小肠CT图像识别描述人工神经网络模型,采用ResNet 101和Faster R-CNN联合提取图像特征信息进行ROI融合建立图像编码,采用LSTM进行图像解码输出CT图像诊断报告。设计11个病变图像特征标签,选择我院2020年1月—2022年1月行512层螺旋CT薄层扫描病例材料1572套,材料覆盖正常图像及出血、炎性息肉等9种病变类型,按7∶3随机分为训练组和测试组,对模型进行训练并展开性能测试,评价模型输出的CT诊断文字报告质量、诊断准确率及病变部位提取正确率。结果:文字报告质量评分为(4.0325±0.684)分,出现错误评估项样本占比0.8%,仅语句结合约35%存在不合理现象;各病变类型诊断准确率均在97%左右,仅腺癌存在轻微的诊断为腺瘤性息肉现象,整体病变类型诊断正确率97.17%;病变部位正确识别提取率99.43%。结论:基于ResNet 101、Faster R-CNN、LSTM建立人工神经网络模型,进行小肠512层螺旋CT扫描图像的诊断识别,可准确定位图像病变部位,根据病变部位图像特征准确进行病变类型诊断,并就11个CT图像特征进行文字化描述,输出符合医师阅读理解的图像诊断报告,并发现部分医师人工阅片遗漏错误的地方,可为医师提供更为丰富、有效、准确的CT图像诊断信息,有利于医师作出正确的诊断。 展开更多
关键词 小肠病变 人工智能 薄层扫描ct 图像诊断描述
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工业CT大视野扫描的统一形式及其重建算法
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作者 陈云斌 李寿涛 +2 位作者 刘清华 李敬 王远 《中国体视学与图像分析》 2024年第2期138-147,共10页
工业CT大视野扫描模式包括探测器偏置扫描和转台偏置扫描。实际应用中,大视野扫描通常同时存在探测器偏置和转台偏置。针对上述情况,本文提出了大视野扫描的统一形式,即探测器、转台联合偏置扫描。通过分析投影地址的重复采样次数,本文... 工业CT大视野扫描模式包括探测器偏置扫描和转台偏置扫描。实际应用中,大视野扫描通常同时存在探测器偏置和转台偏置。针对上述情况,本文提出了大视野扫描的统一形式,即探测器、转台联合偏置扫描。通过分析投影地址的重复采样次数,本文提出基于Parker函数加权的联合偏置重建算法,并对一个考古文物进行大视野扫描实验进行验证。实验结果表明,本文提出的大视野扫描统一模型及其重建算法切实可行,具有一定的工程实用价值。 展开更多
关键词 工业ct 探测器偏置扫描 转台偏置扫描
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