共查询到20条相似文献,搜索用时 15 毫秒
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如何实现快速磁共振成像(Magnetic resonance imaging, MRI)是MRI医学图像技术发展和应用的关键, 现有的快速MRI成像技术在成像速度及成像质量方面仍存在很大的提升空间.本文基于Contourlet变换, 对磁共振图像进行稀疏表示, 并结合传统PF-CS-SENSE框架, 提出一种基于Contourlet变换的组合MRI重构方法, 即PF-FICOTA-SENSE.考虑到组合MRI采样模式、低频数据的对称性以及Contourlet能更好地拟合曲线轮廓等因素, 进一步提出一种快速组合MRI方法, 该方法通过将低频部分重建由FICOTA重建替换为直接填零的傅里叶重建, 来实现快速重建.对比实验表明, 无论在MRI重构速度还是重构质量方面, 本文算法均能取得更好的性能. 相似文献
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段先华 《计算机应用与软件》2007,24(11):37-40
在分析心脏MR图像特点的基础上,提出了先对心脏MRI图像进行K均值聚类,把K均值聚类后的图像作为特征图像,在特征上用Song和Chan提出的快速分割方法进行粗分割,再用粗分割的曲线作为水平集的初始曲线,在心脏MRI图像上用Chan和Vese方法进行细分割的心脏MR图像分割方法.并对Song和Chan快速算法中扫描图像的区域进行了改进,提高了分割速度.分割实验证明,用该方法能够快速、准确地分割心脏MRI图像. 相似文献
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Olsson S 《Computer methods and programs in biomedicine》2001,66(1):129-135
To study the diffusion, access, use, and utilisation of Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) in Sweden a national survey was carried out by a written questionnaire mailed to all public and private hospitals and clinics in 1997. To get a survey of CT and MRI in other countries a request asking for number of units was sent to recognised authorities and individuals in selected countries. CT and MRI were introduced in Sweden in 1973 and 1984 respectively. The diffusion of CT and MRI in Sweden are amongst the highest in the world. Considering the small size of the country and the medical community (e.g. facilitating transparency in indications for use of CT and MRI) and the relatively homogeneous health care system (tax based finance system) the regional variations in access, use, and utilisation of CT and MRI were surprisingly large. For example: In 1996 the number of CT examinations per 100.000 inhabitants varied from 3.344 to 4.705 between the regions. The MRI examinations varied from 751 to 1.858. Some of the differences may be explained by demographic factors. Also, reimbursement policies by the county councils for CT and MRI examinations varied which gave different incentives for patient referrals. However, to explain most of the differences more research is needed. Factors like proportion of elderly amongst the populations in the regions and other socio-demographic factors, proportion of research orientation of examinations and national medical specialities, organisation of the health care, etc. may to a greater extent explain the differences. 相似文献
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磁共振成像(MRI)作为一种典型的非侵入式成像技术,可产生高质量的无损伤和无颅骨伪影的脑影像,为脑肿瘤的诊断和治疗提供更为全面的信息,是脑肿瘤诊疗的主要技术手段。MRI脑肿瘤自动分割利用计算机技术从多模态脑影像中自动将肿瘤区(坏死区、水肿区、非增强肿瘤区和增强肿瘤区)和正常组织区进行分割和标注,对于辅助脑肿瘤的诊疗具有重要作用。本文对MRI脑肿瘤图像分割的深度学习方法进行了总结与分析,给出了各类方法的基本思想、网络架构形式、代表性改进方案以及优缺点总结等,并给出了部分典型方法在BraTS(multimodal brain tumor segmentation)数据集上的性能表现与分析结果。通过对该领域研究方法进行综述,对现有基于深度学习的MRI脑肿瘤分割研究方法进行了梳理,作为新的发展方向,MRI脑肿瘤图像分割的深度学习方法较传统方法已取得明显的性能提升,已成为领域主流方法并持续展现出良好的发展前景,有助于进一步推动MRI脑肿瘤分割在临床诊疗上的应用。 相似文献
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Model Predictive Control (MPC) Relevant Identification (MRI) methods are a good option for identification, if there is model structure mismatch. Herein a new MRI method, named Enhanced Multistep Prediction Error Method (EMPEM), is proposed. EMPEM combines the best characteristics of others MRI methods in a single algorithm. It was developed to identify either closed-loop or open-loop systems; its convergence and stability make it perform better than the other presented methods. To show the advantages of EMPEM, a comparison is made against two other methods (one MRI and one PEM). The statistical analysis indicates that in the cases studied, the performance and the robustness of the new method is equal or better than the other ones. 相似文献
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Multimedia Tools and Applications - Magnetic resonance images (MRI) is the imperative imaging modality utilized in medical diagnosis tool for detecting brain tumors. The MRI possess the capability... 相似文献
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Rajasree R. Columbus C. Christopher Shilaja C. 《Neural computing & applications》2021,33(11):5543-5553
Neural Computing and Applications - MRI is a broadly used imaging method to determine glioma-based tumors. During image processing, MRI provides large image information, and therefore, an accurate... 相似文献
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为了更好地对CT和MRI图像进行融合,提出了一种指数型模糊加权熵自适应融合规则和改进的PCNN区域信息融合规则在多小波基的框架下进行CT和MRI医学图像的融合方法。对待融合图像进行多小波基的分解,对不同频率分量采用不同融合算法。实验表明,算法明显优于其他融合算法。它提高了图像的清晰度,较大程度保留了细节信息,具有边缘信息突出,亮度对比度高的优点。 相似文献
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Multimedia Tools and Applications - Optimal secure visual cryptography for brain MRI medical image is proposed in this paper. Initially, the brain MRI images are selected and then discrete wavelet... 相似文献
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Sudipta Roy Debnath Bhattacharyya Samir Kumar Bandyopadhyay Tai-Hoon Kim 《Frontiers of Computer Science》2017,11(4):717-727
This paper propose a computerized method of magnetic resonance imaging (MRI) of brain binarization for the uses of preprocessing of features extraction and brain abnormality identification. One of the main problems of MRI binarization is that many pixels of brain part cannot be correctly binarized due to extensive black background or large variation in contrast between background and foreground of MRI. We have proposed a binarization that uses mean, variance, standard deviation and entropy to determine a threshold value followed by a non-gamut enhancement which can overcome the binarization problem of brain component. The proposed binarization technique is extensively tested with a variety of MRI and generates good binarization with improved accuracy and reduced error. A comparison is carried out among the obtained outcome with this innovative method with respect to other well-known methods. 相似文献
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基于窄带水平集的曲线演化与左心室MRI图像分割 总被引:2,自引:1,他引:2
文章研究了基于窄带水平集的曲线演化方法并应用于心脏的MRI图像分割。分析了窄带的生成技术,提出了基于模板的距离函数生成方法;针对MRI图像的特点,给出了一种分割MRI图像的水平集速度函数,以处理图像中出现的区域灰度不一致性以及弱边界现象。MRI图像的分割实验证明了该文算法的有效性。 相似文献
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Christilin D. M. Annie Brighty Mary Dr M. Safish 《Multimedia Tools and Applications》2021,80(13):19441-19457
Multimedia Tools and Applications - While denoising 3D MRI, structural preservation is a very critical process in the medical region. However, Rician noise in MRI has affected the image quality... 相似文献
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Huang Jiahao Ding Weiping Lv Jun Yang Jingwen Dong Hao Del Ser Javier Xia Jun Ren Tiaojuan Wong Stephen T. Yang Guang 《Applied Intelligence》2022,52(13):14693-14710
Applied Intelligence - In clinical medicine, magnetic resonance imaging (MRI) is one of the most important tools for diagnosis, triage, prognosis, and treatment planning. However, MRI suffers from... 相似文献
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M. A. Balafar 《Artificial Intelligence Review》2014,41(3):429-439
Image segmentation is at a preliminary stage of inclusion in diagnosis tools and the accurate segmentation of brain MRI images is crucial for a correct diagnosis by these tools. Due to in-homogeneity, low contrast, noise and inequality of content with semantic; brain MRI image segmentation is a challenging job. A review of the Gaussian Mixture Model based segmentation algorithms for brain MRI images is presented. The review covers algorithms for segmentation algorithms and their comparative evaluations based on reported results. 相似文献