检索结果-内蒙古大学图书馆

A novel method for improving the accuracy of MR-derived patient-specific vascular models using X-ray angiography

ENGINEERING WITH COMPUTERS 2022年第5期38卷 3879-3891页

作者： Horn, John D. Starosolski, Zbigniew Johnson, Michael J. Meoded, Avner Hossain, Shaolie S. Texas Heart Inst Mol Cardiol Res Lab 6770 Bertner Ave Houston TX 77030 USA Texas Childrens Hosp Dept Radiol Houston TX 77030 USA Baylor Coll Med Dept Radiol Houston TX 77030 USA Univ Texas Austin Oden Inst Computat Engn & Sci Austin TX 78712 USA

MR imaging, a noninvasive radiation-free imaging modality commonly used during clinical follow-up, has been widely utilized to reconstruct realistic 3D vascular models for patient-specific analysis. In recent work, we used patient-specific hemodynamic analysis of the circle of Willis to noninvasively assess stroke risk in pediatric Moyamoya disease (MMD)-a progressive steno-occlusive cerebrovascular disorder that leads to recurrent stroke. The objective was to identify vascular regions with critically high wall shear rate (WSR) that signifies elevated stroke risk. However, sources of error such as insufficient resolution of MR images can negatively impact vascular model accuracy, especially in areas of severe pathological narrowing, and thus diminish clinical relevance of simulation results, as local hemodynamics are sensitive to vessel geometry. To improve the accuracy of MR-derived vascular models, we have developed a novel method for adjusting model vessel geometry utilizing 2D X-ray angiography (XA), which is considered the gold standard for clinically assessing vessel caliber. In this workflow, "virtual angiographies" (VAs) of 3D MR-derived vascular models are conducted, producing 2D projections that are compared with corresponding XA images to guide the local adjustment of modeled vessels. This VA-comparison-adjustment loop is iterated until the two agree, as confirmed by an expert neuroradiologist. Using this method, we generated models of the circle of Willis of two patients with a history of unilateral stroke. Blood flow simulations were performed using a Navier-Stokes solver within an isogeometric analysis framework, and WSR distributions were quantified. Results for one patient show as much as 45% underestimation of local WSR in the stenotic left anterior cerebral artery (LACA), and up to a 56% underestimation in the right anterior cerebral artery when using the initial MR-derived model compared to the XA-adjusted model. To evaluate whether XA-based adjus

关键词： Computer-aided design image-based modeling Segmentation Stroke Wall shear rate

来源：评论

学校读者我要写书评

暂无评论

image-based modeling TECHNIQUES FOR ARCHITECTURAL HERITAGE 3D DIGITALIZATION: LIMITS AND POTENTIALITIES 24

IMAGE-BASED MODELING TECHNIQUES FOR ARCHITECTURAL HERITAGE 3...

引用

24th International CIPA Symposium

作者： Santagati, C. Inzerillo, L. Di Paola, F. IEMEST Dept Commun Interact Graph & Augmented Real Ist Euro Mediterraneo Sci & Tecnol I-90139 Palermo Italy Univ Catania Dept Architecture I-95125 Catania Italy Univ Palermo Dept Architecture I-90139 Palermo Italy

ISBN: (纸本)9781629935201

3D reconstruction from images has undergone a revolution in the last few years. Computer vision techniques use photographs from data set collection to rapidly build detailed 3D models. The simultaneous applications of different algorithms (MVS), the different techniques of image matching, feature extracting and mesh optimization are inside an active field of research in computer vision. The results are promising: the obtained models are beginning to challenge the precision of laser-based reconstructions. Among all the possibilities we can mainly distinguish desktop and web-based packages. Those last ones offer the opportunity to exploit the power of cloud computing in order to carry out a semi-automatic data processing, thus allowing the user to fulfill other tasks on its computer;whereas desktop systems employ too much processing time and hard heavy approaches. Computer vision researchers have explored many applications to verify the visual accuracy of 3D model but the approaches to verify metric accuracy are few and no one is on Autodesk 123D Catch applied on Architectural Heritage Documentation. Our approach to this challenging problem is to compare the 3Dmodels by Autodesk 123D Catch and 3D models by terrestrial LIDAR considering different object size, from the detail (capitals, moldings, bases) to large scale buildings for practitioner purpose.

关键词： image-based modeling 3D reconstruction Computer Vision Architectural Heritage Laser scanning

来源：评论

学校读者我要写书评

暂无评论

Haemodynamic effects of non-Newtonian fluid blood on the abdominal aorta before and after double tear rupture

引用

MEDICAL ENGINEERING & PHYSICS 2024年 130卷 104205-104205页

作者： Wang, Yiwen Zhou, Changli Wu, Xuefeng Liu, Lijia Deng, Li Harbin Univ Sci & Technol Minist Educ Key Lab Adv Mfg & Intelligent Technol Harbin 150080 Peoples R China Harbin Med Univ Affiliated Hosp 1 Dept Cardiovasc Surg Harbin 150086 Peoples R China

Objectives: Intimal tears caused by aortic dissection can weaken the arterial wall and lead to aortic aneurysms. However, the effect of different tear states on the blood flow behaviour remains complex. This study uses a novel approach that combines numerical haemodynamic simulation with in vitro experiments to elucidate the effect of arterial dissection rupture on the complex blood flow state within the abdominal aneurysm and the endogenous causes of end-organ malperfusion. Materials and methods: based on the CT imaging data and clinical physiological parameters, the overall arterial models including aortic dissection and aneurysm with single tear and double tear were established, and the turbulence behaviours and haemodynamic characteristics of arterial dissection and aneurysm under different blood pressures were simulated by using non-Newtonian flow fluids with the pulsatile blood flow rate of the clinical patients as a cycle, and the results of the numerical simulation were verified by in vitro simulation experiments. Results: Hemodynamic simulations revealed that the aneurysm and single-tear false lumen generated a maximum pressure of 320.591 mmHg, 267 % over the 120 mmHg criterion. The pressure differential generates reflux, leading to a WSS of 2247.9 Pa at the TL inlet and blood flow velocities of up to 6.41 m/s inducing extend of the inlet. DTD Medium FL instantaneous WP above 120 mmHg Standard 151 % Additionally, there was 82.5 % higher flow in the right iliac aorta than in the left iliac aorta, which triggered malperfusion. Thrombus was accumulated distal to the tear and turbulence. These results are consistent with the findings of the in vitro experiments. Conclusions: This study reveals the haemodynamic mechanisms by which aortic dissection induces aortic aneurysms to produce different risk states. This will contribute to in vitro simulation studies as a new fulcrum in the process of moving from numerical simulation to clinical trials.

关键词： Aortic dissection image-based modeling Aortic hemodynamics Computational fluid dynamics

来源：评论

学校读者我要写书评

暂无评论

Voxel-based simulation of flow and temperature in the human nasal cavity

引用

COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 2021年第4期24卷 459-466页

作者： Kimura, Shinya Miura, Shuta Sera, Toshihiro Yokota, Hideo Ono, Kenji Doorly, Denis J. Schroter, Robert C. Tanaka, Gaku Chiba Univ Grad Sch Engn Chiba Japan Kyushu Univ Dept Mech Engn Fukuoka Japan RIKEN Ctr Adv Photon Image Proc Res Team Wako Saitama Japan Kyushu Univ Res Inst Informat Technol Interdisciplinary Computat Sci Sect Fukuoka Japan Imperial Coll London Dept Aeronaut London England Imperial Coll London Dept Bioengn London England

The nasal airway is an extremely complex structure, therefore grid generation for numerical prediction of airflow in the nasal cavity is time-consuming. This paper describes the development of a voxel-based model with a Cartesian structured grid, which is characterized by robust and automatic grid generation, and the simulation of the airflow and air-conditioning in an individual human nasal airway. Computed tomography images of a healthy adult nose were used to reconstruct a virtual three-dimensional model of the nasal airway. Simulations of quiet restful inspiratory flow were then performed using a Neumann boundary condition for the energy equation to adequately resolve the flow and heat transfer. General agreements of airflow patterns, which were a high-speed jet posterior to the nasal valve and recirculating flow that occupied the anterior part of the upper cavity, and temperature distributions of the airflow and septum wall were confirmed by comparing in-vivo measurements with numerical simulation results.

关键词： Biomedical applications computational methods numerical simulations super-computing nasal airflow image-based modeling

来源：评论

学校读者我要写书评

暂无评论

Digital models for the knowledge, protection and enhancement of historic bridges. Definition of an operational protocol.

引用

Procedia Structural Integrity 2024年 64卷 2222-2229页

作者： Leonardo Paris Maria Laura Rossi Sapienza University of Rome Square Aldo Moro n.5 00185 Italy

The tools and investigation methodologies for understanding architectural artefacts have received a notable boost in the last decade thanks to the rapid evolution of technologies. The application of investigation methodologies in a specific area such as that of bridges, especially if of historical-monumental value, has highlighted some peculiarities such as, for example, the relationship with the environmental context and the technical-constructive component; the bridge, being in fact also an infrastructural work, must also be investigated from the point of view of its structural behavior. Beyond the consolidated scientific methodology, every significant activity represents a unicum, just as every object is unique. However, the experiments carried out in carrying out our research on some bridges of particular historical value have allowed us to define a procedural protocol and codify a methodology that can be used and repeated in similar examples. The setting of this protocol is not intended as a simplification and standardization of the detection process, but rather as an aid within a critical path, in order to obtain an optimization of the entire detection and analysis process. In addition to the application of procedures for the acquisition and processing of three-dimensional models consolidated in recent years, we also wanted to test the potential of HBIM (Heritage Building Information modeling) processes applied to Cultural Heritage.

关键词： 3D modeling Scanner laser Mobile Laser image-based modeling Cultural Heritage

来源：评论

学校读者我要写书评

暂无评论

Quantification of the heterogeneous effect of static and dynamic perivascular structures on patient-specific local aortic wall mechanics using inverse finite element modeling and DENSE MRI

引用

JOURNAL OF BIOMECHANICS 2022年 138卷 111119-111119页

作者： Bracamonte, H. Johane Wilson, S. John Soares, S. Joao Virginia Commonwealth Univ Coll Engn Dept Mech & Nucl Engn 401 West Main StPOB 843015 Richmond VA 23284 USA Virginia Commonwealth Univ Dept Biomed Engn & Pauley Heart Ctr 601 West Main St Richmond VA 23284 USA

Recent studies have highlighted the relevance of perivascular interactions on aortic wall mechanics. Most of the approaches assume static perivascular structures;however, the beating heart dynamically displaces the neighboring aorta. We develop a model to account for the effect of periaortic interactions due to static and dynamic structures by prescribing a moving elastic foundation boundary condition (EFBC) embedded into an inverse finite element algorithm using in vivo displacements from 2D displacement encoding with stimulated echoes (DENSE) MRI as target data. We applied this method at three different locations of interest, the distal aortic arch (DAA), descending thoracic aorta (DTA), and infrarenal abdominal aorta (IAA) for a total of 27 cases in healthy humans. The model reproduces the target diastole-to-systole deformation and bulk displacement of the aortic wall with median displacement errors below 0.5 mm. The EFBC showed good agreement with the location of anatomical features and was consistent among individuals of similar characteristics. Results show that an energy source acting on the adventitia is required to reproduce the displacements measured at the vicinity of the heart, but not at the abdomen. The average adventitial load as a percentage of the luminal pulse-pressure was found to increase with age and to decrease along the descending aorta, from 61% at the DAA to 37% at the DTA, and 30% at the IAA. This approach offers a patient-specific method to estimate in vivo adventitial loads and aortic wall stiffness, which can bring a better understanding of normal and pathological in vivo aortic function.

关键词： Periaortic interactions Perivascular support Tethering Adventitial loads DENSE MRI image-based modeling Inverse model Data assimilation Aorta In vivo function

来源：评论

学校读者我要写书评

暂无评论

Patient-Specific Computational Analysis of Hemodynamics in Adult Pulmonary Hypertension

引用

ANNALS OF BIOMEDICAL ENGINEERING 2021年第12期49卷 3465-3480页

作者： Pillalamarri, Narasimha R. Piskin, Senol Patnaik, Sourav S. Murali, Srinivas Finol, Ender A. Univ Texas San Antonio Dept Mech Engn One UTSA Circle San Antonio TX 78249 USA Istinye Univ Dept Mech Engn Istanbul Turkey Univ Texas Dallas Dept Bioengn Richardson TX 75083 USA Allegheny Hlth Network Div Cardiovasc Med Pittsburgh PA USA Univ Texas San Antonio UTSA UTHSA Joint Grad Program Biomed Engn San Antonio TX USA

Pulmonary hypertension (PH) is a progressive disease characterized by elevated pressure and vascular resistance in the pulmonary arteries. Nearly 250,000 hospitalizations occur annually in the US with PH as the primary or secondary condition. A definitive diagnosis of PH requires right heart catheterization (RHC) in addition to a chest computed tomography, a walking test, and others. While RHC is the gold standard for diagnosing PH, it is invasive and posseses inherent risks and contraindications. In this work, we characterized the patient-specific pulmonary hemodynamics in silico for diverse PH WHO groups. We grouped patients on the basis of mean pulmonary arterial pressure (mPAP) into three disease severity groups: at-risk (18mmHg <= mPAP<25mmHg, denoted with A), mild (25mmHg <= mPAP<40mmHg, denoted with M), and severe (mPAP >= 40mmHg, denoted with S). The pulsatile flow hemodynamics was simulated by evaluating the three-dimensional Navier-Stokes system of equations using a flow solver developed by customizing OpenFOAM libraries (v5.0, The OpenFOAM Foundation). Quasi patient-specific boundary conditions were implemented using a Womersley inlet velocity profile and transient resistance outflow conditions. Hemodynamic indices such as spatially averaged wall shear stress (SAWSS), wall shear stress gradient (WSSG), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT), were evaluated along with the clinical metrics pulmonary vascular resistance (PVR), stroke volume (SV) and compliance (C), to assess possible spatiotemporal correlations. We observed statistically significant decreases in SAWSS, WSSG, and TAWSS, and increases in OSI and RRT with disease severity. PVR was moderately correlated with SAWSS and RRT at the mid-notch stage of the cardiac cycle when these indices were computed using the global pulmonary arterial geometry. These results are promising in the context of a long-term goal of identifying computatio

关键词： Pulmonary hypertension Computational fluid dynamics Pulsatile flow image-based modeling Right heart catheterization

来源：评论

学校读者我要写书评

暂无评论

A Multiscale X-Ray Tomography Study of the Cycled-Induced Degradation in Magnesium-Sulfur Batteries

引用

SMALL METHODS 2021年第5期5卷 p1-13页

作者： Du, Wenjia Hao, Zhangxiang Iacoviello, Francesco Sheng, Lin Guan, Shaoliang Zhang, Zhenyu Brett, Daniel J. L. Wang, Feng Ryan Shearing, Paul R. UCL Dept Chem Engn Electrochem Innovat Lab London WC1E 7JE England UCL Dept Chem Engn Mat & Catalysis Lab London WC1E 7JE England HarwellXPS Rutherford Appleton Lab Res Complex Harwell Didcot OX11 0FA Oxon England Cardiff Univ Sch Chem Cardiff CF10 3AT Wales Faraday Inst Quad OneHarwell Sci & Innovat Campus Didcot OX11 0RA Oxon England

Rechargeable Mg/S batteries have the potential to provide a compelling battery for a range of applications owing to their high capacity and gravimetric energy density, safety, and low-cost construction. However, the Mg/S energy storage is not widely developed and deployed due to technical challenges, which include short cycle lifespan and lack of suitable electrolyte. To study the microstructure degradation of Mg/S batteries, multiscale X-ray tomography, an inherently nondestructive method, is performed on dismantled Swagelok Mg/S cells comprising a graphene-sulfur cathode and a super-P separator. For the first time, 3D microstructure visualization and quantification reveal the dissolution (volume fraction decreases from 13.5% to 0.7%, surface area reduces from 2.91 to 1.74 mu m(2) mu m(-3)) and agglomeration of sulfur particles, and the carbon binder densification after 10 cycles. Using tomography data, the image-based simulations are then performed. The results show that the insoluble polysulfides can inevitably block the Mg2+ transportation via shuttle effect. The representative volume should exceed 8200 mu m(3) to represent bulk cathode. This work elucidates that the Mg/S cell performance is significantly affected by microstructural degradation, and moreover demonstrates how multiscale and multimodal characterization can play an indispensable role in developing and optimizing the Mg/S electrode design.

关键词： cycling image-based modeling Mg/S batteries X-ray microtomography X-ray nanotomography

来源：评论

学校读者我要写书评

暂无评论

A Brush-Spin-Coating Method for Fabricating In Vitro Patient-Specific Vascular Models by Coupling 3D-Printing

引用

CARDIOVASCULAR ENGINEERING AND TECHNOLOGY 2021年第2期12卷 200-214页

作者： Chi, Qing-Zhuo Mu, Li-Zhong He, Ying Luan, Yong Jing, Yu-Chen Dalian Univ Technol Minist Educ Affiliat Key Lab Ocean Energy Utilizat & Energy Conservat Dalian 116024 Peoples R China Dalian Med Univ Affiliated Hosp 1 Dept Anesthesiol Dalian 116011 Peoples R China China Med Univ Affiliated Hosp 1 Dept Vasc Surg Shenyang 110001 Peoples R China

Purpose In vitro patient-specific flexible vascular models are helpful for understanding the haemodynamic changes before and after endovascular treatment and for effective training of neuroendovascular interventionalists. However, it is difficult to fabricate models of overall unified or controllable thickness using existing manufacturing methods. In this study, we developed an improved and easily implemented method by combining 3D printing and brush-spin-coating processes to produce a transparent silicone model of uniform or varied thickness. Methods First, a water-soluble inner-skeleton model, based on clinical data, was printed on a 3D printer. The skeleton model was subsequently fixed in a single-axis-rotation machine to enable continuous coating of silicone, the thickness of which was manually controlled by adsorption and removal of excess silicone in a brush-spinning operation. After the silicone layer was solidified, the inner skeleton was further dissolved in a hot water bath, affording a transparent vascular model with real geometry. To verify the controllability of the coating thickness by using this method, a straight tube, an idealised aneurysm model, a patient-specific aortic arch model, and an abdominal aortic aneurysm model were manufactured. Results The different thicknesses of the manufactured tubes could be well controlled, with the relative standard deviations being 5.6 and 8.1% for the straight and aneurysm tubes, respectively. Despite of the diameter changing from 33 to 20 mm in the patient-specific aorta, the thickness of the fabricated aortic model remains almost the same along the longitudinal direction with a lower standard deviation of 3.1%. In the more complex patient-specific abdominal aneurysm model, varied thicknesses were realized to mimic the measured data from the CT images, where the middle of the aneurysm was with 2 mm and abdominal aorta as well as the iliac arteries had the normal thickness of 2.3 mm. Conclusion Through the brush

关键词： 3D printing image-based modeling Transparent compliant vessel Controllable thickness Surgical simulation

来源：评论

学校读者我要写书评

暂无评论

Automatic extraction of the mitral valve chordae geometry for biomechanical simulation

引用

INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY 2021年第5期16卷 709-720页

作者： Panicheva, Daryna Villard, Pierre-Frederic Hammer, Peter E. Perrin, Douglas Berger, Marie-Odile Univ Lorraine LORIA INRIA CNRS Nancy France Harvard Sch Engn & Appl Sci Cambridge MA 02138 USA Harvard Med Sch Boston MA 02115 USA

Purpose Mitral valve computational models are widely studied in the literature. They can be used for preoperative planning or anatomical understanding. Manual extraction of the valve geometry on medical images is tedious and requires special training, while automatic segmentation is still an open problem. Methods We propose here a fully automatic pipeline to extract the valve chordae architecture compatible with a computational model. First, an initial segmentation is obtained by sub-mesh topology analysis and RANSAC-like model-fitting procedure. Then, the chordal structure is optimized with respect to objective functions based on mechanical, anatomical, and image-based considerations. Results The approach has been validated on 5 micro-CT scans with a graph-based metric and has shown an 87.5% accuracy rate. The method has also been tested within a structural simulation of the mitral valve closed state. Conclusion Our results show that the chordae architecture resulting from our algorithm can give results similar to experienced users while providing an equivalent biomechanical simulation.

关键词： image-based modeling Mitral valve Graph-based validation Biomechanical simulation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：