检索结果-内蒙古大学图书馆

A heterogeneous patient-specific model of glioblastoma multiforme tumor through an inverse problem

INVERSE PROBLEMS 2024年第12期40卷 125025-125025页

作者： Fotouhi, Morteza Yousefnezhad, Mohsen Sharif Univ Technol Dept Math Sci Tehran Iran Shiraz Univ Coll Sci Dept Math Shiraz Iran

This paper presents a mathematical framework for the prognosis of glioblastoma brain tumor growth on a patient-specific basis, employing a heterogeneous image-driven methodology. The approach utilizes a reaction-diffusion model to capture the diffusion and proliferation dynamics of tumor cell density, integrated with an inverse problem based on partial differential equation-constrained formulation that links the model to medical images. We establish a theoretical framework that forms a robust foundation for our proposed methodology. Then a numerical algorithm is introduced to implement the framework effectively. We also validate the efficacy of our approach using synthetic tumors on a real brain magnetic resonance image. This work significantly contributes to advancing our understanding of glioma dynamics and offers a promising avenue for personalized treatments through the estimation of spatially varying parameters.

关键词： inverse problem PDE constrained optimization reaction-diffusion equations patient-specific model glioblastoma multiforme

来源：评论

学校读者我要写书评

暂无评论

A Homoclinic Orbit in a patient-specific model of Hashimoto's Thyroiditis

引用

DIFFERENTIAL EQUATIONS AND DYNAMICAL SYSTEMS 2020年第2期28卷 401-418页

作者： Pandiyan, Balamurugan Merrill, Stephen J. Benvenga, Salvatore Univ Wisconsin Dept Math 800 W Main St Whitewater WI 53190 USA Marquette Univ Dept MSCS Milwaukee WI 53401 USA Univ Messina Policlin Div Endocrinol I-98125 Messina Italy

Hashimoto's thyroiditis is an autoimmune disorder of the thyroid gland. In Hashimoto disease, the immune system damages the follicular cells of the thyroid gland through humoral and cellular-mediated responses which result in diminishing production of thyroid hormones in the blood over time. Using a patient-specific model of Hashimoto's thyroiditis, we describe the natural history of Hashitoxicosis in genetically susceptible individuals. Hashitoxicosis means a sudden leakage of thyroid hormones from the gland. The main result of this present work is to show the existence of a homoclinic orbit which forms the boundary for the asymptotically stable interior diseased steady state. This homoclinic orbit corresponds to the clinical condition of Hashitoxicosis.

关键词： Homoclinic orbit Hashitoxicosis Hashimoto's thyroiditis patient-specific model

来源：评论

学校读者我要写书评

暂无评论

Computational Fluid Dynamics Analysis of Carotid-Ophthalmic Aneurysms with Concomitant Ophthalmic Artery Infundibulum in a patient-specific model

引用

WORLD NEUROSURGERY 2019年 125卷 E1023-E1033页

作者： Ba, Dechun Zhu, Zhipeng Yue, Xiangji Xu, Ping Yan, Pengfei Xiao, Dongdong Northeastern Univ Sch Mech Engn & Automat Shenyang 110819 Liaoning Peoples R China Huazhong Univ Sci & Technol Union Hosp Tongji Med Coll Dept Neurol Wuhan 430022 Hubei Peoples R China Huazhong Univ Sci & Technol Union Hosp Tongji Med Coll Dept Neurosurg Wuhan 430022 Hubei Peoples R China

BACKGROUND: Although previous studies have reported cases of coexistence of carotid-ophthalmic aneurysm and ophthalmic artery (OA) infundibulum, the hemodynamic characteristics of this complicated structure and its damaging effects on vision remain to be elucidated. The aim of the present study was to analyze this artery structure using computational fluid dynamics (CFD) techniques. METHODS: We have presented the case of a patient with a diagnosis of carotid-ophthalmic aneurysm, who had been experiencing blurred vision. A transient analysis was performed to investigate the blood flowing in the parent artery. Hemodynamic parameters such as streamline, wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time were obtained. RESULTS: When the inlet velocity of the parent artery was at the second peak, the flow rate and intensity of the vortex reached their maximum. In the aneurysm neck, a region of high time-averaged WSS (TAWSS) and a region of low TAWSS with a high OSI coexisted. In addition, a relaxation area was found. In the aneurysm dome, the minimum TAWSS was 2.5 Pa, the maximum OSI was 0.48, and the 2 regions did not overlap. In the OA infundibulum, the maximum OSI and relative residence time were 0.47 and 39.2, respectively;the minimum TAWSS was 0.59 Pa. CONCLUSIONS: We detected aneurysm regions that were susceptible to further expansion and assessed the rupture risk of each region. The relaxation area could promote aneurysm progression. In addition, the location of the vortex shear force center varied with time. Finally, double vortex streamlines influenced the blood supply through the OA, impairing the vision. Infundibulum might promote thrombus formation and, hence, retard OA blood flow.

关键词： Carotid-ophthalmic aneurysm Computational fluid dynamics Infundibular dilatation Infundibulum Non-Newtonian fluid patient-specific model

来源：评论

学校读者我要写书评

暂无评论

patient-specific model-based segmentation of brain tumors in 3D intraoperative ultrasound images

引用

INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY 2018年第3期13卷 331-342页

作者： Ilunga-Mbuyamba, Elisee Gabriel Avina-Cervantes, Juan Lindner, Dirk Arlt, Felix Fulbert Ituna-Yudonago, Jean Chalopin, Claire Univ Guanajuato Div Engn CA Telemat Campus Irapuato Salamanca Salamanca 36885 Spain Univ Hosp Leipzig Dept Neurosurg D-04103 Leipzig Germany Univ Leipzig ICCAS D-04103 Leipzig Germany

Intraoperative ultrasound (iUS) imaging is commonly used to support brain tumor operation. The tumor segmentation in the iUS images is a difficult task and still under improvement because of the low signal-to-noise ratio. The success of automatic methods is also limited due to the high noise sensibility. Therefore, an alternative brain tumor segmentation method in 3D-iUS data using a tumor model obtained from magnetic resonance (MR) data for local MR-iUS registration is presented in this paper. The aim is to enhance the visualization of the brain tumor contours in iUS. A multistep approach is proposed. First, a region of interest (ROI) based on the specific patient tumor model is defined. Second, hyperechogenic structures, mainly tumor tissues, are extracted from the ROI of both modalities by using automatic thresholding techniques. Third, the registration is performed over the extracted binary sub-volumes using a similarity measure based on gradient values, and rigid and affine transformations. Finally, the tumor model is aligned with the 3D-iUS data, and its contours are represented. Experiments were successfully conducted on a dataset of 33 patients. The method was evaluated by comparing the tumor segmentation with expert manual delineations using two binary metrics: contour mean distance and Dice index. The proposed segmentation method using local and binary registration was compared with two grayscale-based approaches. The outcomes showed that our approach reached better results in terms of computational time and accuracy than the comparative methods. The proposed approach requires limited interaction and reduced computation time, making it relevant for intraoperative use. Experimental results and evaluations were performed offline. The developed tool could be useful for brain tumor resection supporting neurosurgeons to improve tumor border visualization in the iUS volumes.

关键词： Brain tumor segmentation Intraoperative ultrasound Image registration patient-specific model

来源：评论

学校读者我要写书评

暂无评论

Multi-view stereo in the operating room allows prediction of healing complications in a patient-specific model of reconstructive surgery

引用

JOURNAL OF BIOMECHANICS 2018年 74卷 202-206页

作者： Lee, Taeksang Turin, Sergey Y. Gosain, Arun K. Tepole, Adrian Buganza Purdue Univ Sch Mech Engn W Lafayette IN 47907 USA Northwestern Univ Feinberg Sch Med Chicago IL 60611 USA Purdue Univ Weldon Sch Biomed Engn W Lafayette IN 47907 USA

Excessive mechanical stress leads to wound healing complications following reconstructive surgery. However, this knowledge is not easily applicable in clinical scenarios due to the difficulty in measuring stress contours during complex tissue rearrangement procedures. Computational tools have been proposed as an alternative to address this need, but obtaining patient specific geometries with an affordable and flexible setup has remained a challenge. Here we present a methodology to determine the stress contours from a reconstructive procedure on a patient-specific finite element model based on multi-view stereo (MVS). MVS is a noninvasive technology that allows reconstruction of 3D geometries using a standard digital camera, making it ideal for the operating room. Finite element analysis can then be used on the patient-specific geometry to perform a virtual surgery and predict regions at risk of complications. We applied our approach to the case of a 7-year-old patient who was treated to correct a cranial contour deformity and resect two large areas of scalp scarring. The simulation showed several zones of high stress, particularly near the suture lines at the distal ends of the flaps. The patient did show delayed healing and partial flap tip necrosis at one of such predicted regions at the 30-day follow up visit. Our results further establish the application of computational tools in individualized medical scenarios to advance preoperative planing and anticipate regions of concern immediately after surgery. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Finite element analysis Multi-view stereo Virtual surgery Wound healing complications Local tissue rearrangement patient-specific model

来源：评论

学校读者我要写书评

暂无评论

LEVERAGING SIMULATION DATA FOR LEARNING A patient-specific model TO LOCALIZE THE ORIGIN OF VENTRICULAR ACTIVATION 15

LEVERAGING SIMULATION DATA FOR LEARNING A PATIENT-SPECIFIC M...

引用

15th IEEE International Symposium on Biomedical Imaging (ISBI)

作者： Alawad, Mohammed Wang, Linwei Rochester Inst Technol Rochester NY 14623 USA King Abdullah Int Med Res Ctr Riyadh Saudi Arabia

ISBN: (纸本)9781538636367

A data-driven model able to automatically localize the origin of abnormal ventricular activation from electrocardiograms will have the potential to improve clinical interventions for a variety of cardiac arrhythmias, such as premature ventricular contraction (PVC). Unfortunately, due to the large anatomical and physiological variations across individuals, a patient-specific model is necessary for an accurate localization. Such models are difficult to implement in clinical practice because the training data on each patient have to be obtained through invasive and expensive procedures. This paper proposes to overcome this shortage of clinical data by transferring the knowledge extracted from a large set of patient-specific simulation data to a small set of clinical data on the patient. A domain adaption approach is used to learn the "domain shift" between simulation and clinical data, while a novel error modeling method is developed to take into account potential simulation errors during domain adaption. The presented method is evaluated on three PVC patients. In comparison to training a patient-specific model purely from clinical data, or a combination of simulation and clinical data without considering domain shift, the presented method is able to improve the localization accuracy, especially when there is only a small number of clinical data available for training.

关键词： Domain adaptation patient-specific model premature ventricular contraction electrocardiograms

来源：评论

学校读者我要写书评

暂无评论

A patient specific forecasting model for human albumin based on deep neural networks

引用

COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020年 196卷 105555-105555页

作者： Lei, Cheng Wang, Yu Zhao, Jia Li, Kexun Jiang, Hua Wang, Qi Beijing Computat Sci Res Ctr Beijing 100193 Peoples R China Univ Elect Sci & Technol China Inst Emergency & Disaster Med Sichuan Acad Med Sci Sichuan Prov Peoples HospSch Med Chengdu 610072 Sichuan Peoples R China Utah State Univ Dept Math & Stat Logan UT 84322 USA Univ South Carolina Dept Math Columbia SC 29208 USA

Background and Objectives: Hypoalbuminemia can be life threatening among critically ill patients. In this study, we develop a patient-specific monitoring and forecasting model based on deep neural networks to predict concentrations of albumin and a set of selected biochemical markers for critically ill patients in real-time. Methods: Under the assumption that metabolism of a patient follows a patient-specific dynamical process that can be determined from sufficient prior data taken from the patient, we apply a machine learning method to develop the patient-specific model for a critically ill, poly-trauma patient. Six representative biochemical markers (albumin (ALB), creatinine (Cr), osmotic pressure (OSM), alanine aminotransferase (ALT), total bilirubin (TB), direct bilirubin (DB)) were collected from the patient while scheduled exogenous albumin injection was administered to the patient for the total of 27 consecutive days. A sliding window of data in 11 consecutive days were used to train and test the neural networks in the model. Results: The obtained dynamical system model represented by neural networks is used to forecast the biochemical markers of the patient in the next 24 h. The relative error between the predictions and the clinical data remains consistently lower than 2%. Conclusions: This study demonstrates that a patient-specific dynamical system model can be established to monitor and forecast dynamical behavior of concentrations of patients' biochemical markers (including albumin) using deep learning methods on neural networks. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Deep learning Critical illness Albumin patient-specific model Dynamical systems Neural networks

来源：评论

学校读者我要写书评

暂无评论

Pulsatile blood flow in the thoracic aorta and aneurysm: a numerical simulation in CAD-built and patient-specific model

引用

JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2017年第10期39卷 3721-3728页

作者： Silveira, Matheus Huebner, Rudolf Navarro, Tulio Pinho Univ Fed Minas Gerais Bioengn Lab Mech Engn Dept Av Pres Antonio Carlos6627 Pampulha Belo Horizonte MG Brazil

Two sets of geometric models were developed for the hemodynamic study of the thoracic aorta (with and without aneurysm): one patient-specific, built from computed tomography and another idealized, constructed in CAD software. The boundary conditions were established by a velocity pulse at the inlet of the thoracic aorta and a pressure pulse at the aorta outlets of an adult, normotensive, and resting subject. The CAD model for the healthy aorta closely approximates the patient-specific one;especially during the systolic peak with maximum percentage difference of 3.2 and 4.6% for, respectively, the pressure and velocity fields. The CAD-constructed aneurysm model, with 60% permanent diametric dilatation, is close to the minimum medical definition of an aortic aneurysm, which allowed the investigation of the minimal physiological changes that an aneurysm brings to the blood flow. Despite the striking difference in size in relation to the aneurysm of the patient-specific model, it was found that in most cases, the physical phenomena were similar in both models.

关键词： Pulsatile blood flow Computational fluid dynamics Thoracic aorta patient-specific model

来源：评论

学校读者我要写书评

暂无评论

Fusion of optical coherence tomography and angiography for numerical simulation of hemodynamics in bioresorbable stented coronary artery based on patient-specific model

引用

COMPUTER ASSISTED SURGERY 2017年第sup1期22卷 127-134页

作者： Huang, Chenxi Zhou, Yuanhang Mao, Xiaoxin Tong, Jianhua Zhang, Lei Chen, Fei Hao, Yongtao Tongji Univ Dept Comp Sci & Technol Shanghai Peoples R China Chongqing Univ Coll Bioengn Chongqing Peoples R China Tongji Univ Shanghai East Hosp Dept Med Image Shanghai Peoples R China Tongji Univ Shanghai Tongji Hosp Dept Cardiol Shanghai Peoples R China

Three-dimensional simulations of coronary artery using finite element analysis are considered as effective means to understand the biomechanical properties after the stent was deployed. Bioresorbable vascular scaffolds are new-generation stents used by people. Intravascular optical coherence tomography is an emerging technique for detecting struts. The common 3D reconstruction methods are using Intravascular Ultrasound (IVUS) or angiographies. However, it loses the details about geometry model. Fusing of optical coherence tomography and angiography to reconstruct the bioresorbable stented coronary artery based on patient-specific mode is an innovative method to reconstruct the high fidelity geometry. This study aimed to use computer-aided design models and computational fluid dynamics research tools to conduct a systematic investigation of blood flow in an isolated artery with realistically deployed coronary stents. Some important hemodynamic factors such as wall shear stress, wall pressure and streamline were calculated. The doctors could evaluate the local hemodynamic alterations within coronary arteries after stent deployment by reconstructing the high-fidelity geometry about each clinical case.

关键词： Bioresorbable vascular scaffolds optical coherence tomography patient-specific model computational fluid dynamics

来源：评论

学校读者我要写书评

暂无评论

Simultaneous pose estimation and patient-specific model reconstruction from single image using maximum penalized likelihood estimation (MPLE)

引用

PATTERN RECOGNITION 2016年 57卷 61-69页

作者： Kang, Xin Yau, Wai-Pan Taylor, Russell H. Univ Hong Kong Dept Orthopaed & Traumatol Hong Kong Hong Kong Peoples R China Johns Hopkins Univ Dept Comp Sci 3400 N Charles St Baltimore MD 21218 USA

Pose estimation and shape reconstruction are two common problems in pattern recognition, which oftentimes are tackled separately. But in some medical applications, both pose and shape of a target anatomy are crucial and have to be estimated from intra-operative two-dimensional images. As pose estimation and shape reconstruction are two coupled problems, previous feature-based methods solved the problems in consecutive stages utilizing statistical shape models (SSMs). Only the mean shape of SSM is used to estimate the pose by finding paired correspondences in the first stage, based on which SSM-regularized surface deformations are performed in the following stages. Such a strategy heavily depends on the paired correspondences. In this paper, bypassing correspondence establishment, a novel method is proposed to simultaneously optimize pose and shape by formulating the coupled problems as a maximum penalized likelihood estimation (MPLE). It models oriented object contours as a mixture of von Mises-Fisher Gaussian distributions, and solves the MPLE effectively using a global optimizer. It utilize the entire knowledge of SSM in both solving pose and reconstructing shape, providing robustness to large offsets in initializations. Leave-one-out cross-validations on 19 dry cadaveric femurs were performed using simulated X-ray images with accurate ground-truth, under various initial conditions. Our method achieved sub-degree rotational and sub-millimeter in-plane translational pose estimation errors, and an approximately one millimeter average mean surface-to-surface distance in shape reconstruction. The reconstruction accuracy is comparable to those reported in the literature using two or more images. The experiment results are encouraging and indicate that an accurate simultaneous 3D-2D pose estimation and surface reconstruction is achievable from one single image. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Pose estimation 3D-2D deformable registration Surface reconstruction Maximum penalized likelihood estimation (MPLE) patient-specific model Image-guided intervention

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：