搜索结果: 1-15 共查到“知识库 生物医学工程 MRI”相关记录29条 . 查询时间(0.265 秒)
研制用于鼻咽癌放射治疗定位的CT/MRI图像配准辅助装置，并且通过组织勾画差异分析使用该装置后所得配准融合图像在临床中的应用意义。方法 在普通的磁共振头颈线圈中设计特定形状的头枕，保持患者在扫描时与CT定位扫描时相同的体位。采用配对t检验分析CT图像与融合图像中腮腺、下颌骨的勾画差异。结果 患者的头颈部CT、MRI图像的配准精度较未使用该装置的图像具有明显的提高，使用该配准图像得到的融合图像、组织...
乳腺DCE-MRI增强场时间序列和组织形变场的联合估计
乳腺肿瘤 动态增强磁共振 图像配准 马尔科夫随机场
2017/1/12
乳腺DCE-MRI扫描过程中，病人运动等会使图像序列产生运动伪影，需要对DCE-MRI时间序列图像进行运动补偿，消除运动伪影的影响.为充分利用数据信息和增强在空间和时间上的先验信息，本文提出了联合估计增强场时间序列和组织形变场的贝叶斯框架.采用离散马尔科夫随机场模型分别对增强场时间序列和组织形变场进行建模和添加平滑约束，并通过分步迭代方式进行估计.利用估计的增强场对DCE-MRI时间序列图像进行“...
一种基于分段迭代的MRI成像涡流补偿方法
梯度电流 涡流补偿 累积误差 分段迭代计算
2014/10/17
在核磁共振成像中,涡流的存在会影响系统的成像质量。梯度电流预增强方法是一种被广泛采用的有效的涡流补偿方法。梯度电流预增强在一个周期内要进行上千次e指数计算,需采用快速的计算方法。迭代计算是普遍采用的涡流补偿快速计算方法,但是存在累积误差放大的问题。针对这种问题,基于迭代计算原理,我们提出了一种改进的分段迭代的MRI成像涡流补偿计算方法。实验结果表明,在计算时间同量级的条件下有效地提高了梯度预增强量...
Comprehensive approach for motion and distortion correction in diffusion weighted MRI
Comprehensive approach motion and distortion correction diffusion weighted MRI
2009/12/23
Comprehensive approach for motion and distortion correction in diffusion weighted MRI.
Estimating intensity variance due to noise in registered images: applications to DT-MRI
intensity variance noise registered images DT-MRI
2009/12/23
Estimating intensity variance due to noise in registered images: applications to DT-MRI.
Brain Structure Segmentation from MRI by Geometric Surface Flow
Brain Structure Segmentation MRI
2009/9/8
We present a method for semiautomatic segmentation of brain structures such as thalamus from MRI images based on the concept of geometric surface flow. Given an MRI image, the user can interactively i...
Optimization of Spiral MRI Using a Perceptual Difference Model
MRI Perceptual Difference Model
2009/9/8
We systematically evaluated a variety of MR spiral imaging acquisition and reconstruction schemes using a computational perceptual difference model (PDM) that models the ability of humans to perceive ...
Reciprocal Benefits of Mass-Univariate and Multivariate Modeling in Brain Mapping: Applications to Event-Related Functional MRI, H215O-, and FDG-PET
MRI H215O FDG-PET
2009/9/8
In brain mapping studies of sensory, cognitive, and motor operations, specific waveforms of dynamic neural activity are predicted based on theoretical models of human information processing. For examp...
Improving Non-Cartesian MRI Reconstruction through Discontinuity Subtraction
Non-Cartesian MRI Discontinuity Subtraction
2009/9/8
Non-Cartesian sampling is widely used for fast magnetic resonance imaging (MRI). Accurate and fast image reconstruction from non-Cartesian k-space data becomes a challenge and gains a lot of attention...
A Note on the Iterative MRI Reconstruction from Nonuniform k-Space Data
the Iterative MRI Nonuniform k-Space Data
2009/9/7
In magnetic resonance imaging (MRI), methods that use a non-Cartesian grid in k-space are becoming increasingly important. In this paper, we use a recently proposed implicit discretisation scheme whic...
Registration of Brain MRI/PET Images Based on Adaptive Combination of Intensity and Gradient Field Mutual Information
MRI/PET Images Intensity
2009/9/7
Traditional mutual information (MI) function aligns two multimodality images with intensity information, lacking spatial information, so that it usually presents many local maxima that can lead to ina...
Brain MRI Segmentation with Multiphase Minimal Partitioning: A Comparative Study
Brain MRI Segmentation Multiphase Minimal Partitioning
2009/9/7
This paper presents the implementation and quantitative evaluation of a multiphase three-dimensional deformable model in a level set framework for automated segmentation of brain MRIs. The segmentatio...
Quantitative and O2 Enhanced MRI of the Pathologic Lung: Findings in Emphysema, Fibrosis, and Cystic Fibrosis
the Pathologic Lung Emphysema Cystic Fibrosis
2009/9/7
Purpose: beyond the pure morphological visual representation, MR imaging offers the possibility to quantify parameters in the healthy, as well as, in pathologic lung parenchyma. Gas exchange is the pr...
Magnetic Field Distribution and Signal Decay in Functional MRI in Very High Fields (up to 9.4 T) Using Monte Carlo Diffusion Modeling
Functional MRI Diffusion Modeling
2009/9/7
Extravascular signal decay rate R2 or R2∗ as a function of blood oxygenation, geometry, and field strength was calculated using a Monte Carlo (MC) algorithm for a wider parameter range than hith...
A Feature-Selective Independent Component Analysis Method for Functional MRI
Feature-Selective Independent Component Functional MRI
2009/9/7
In this work, we propose a simple and effective scheme to incorporate prior knowledge about the sources of interest (SOIs) in independent component analysis (ICA) and apply the method to estimate brai...