Volume 27, Issue 9

Automatic image processing methods are a pre-requisite to efficiently analyze the large amount of image data produced by computed tomography (CT) scanners during cardiac exams. This paper introduces a model-based approach for the fully automatic segmentation of the whole heart (four chambers, myocardium, and great vessels) from 3-D CT images. Model adaptation is done by progressively increasing the degrees-of-freedom of the allowed deformations. This improves convergence as well as segmentation accuracy. The heart is first localized in the image using a 3-D implementation of the generalized Hough transform. Pose misalignment is corrected by matching the model to the image making use of a global similarity transformation. The complex initialization of the multicompartment mesh is then addressed by assigning an affine transformation to each anatomical region of the model. Finally, a deformable adaptation is performed to accurately match the boundaries of the patient's anatomy. A mean surface-to-surface error of 0.82 mm was measured in a leave-one-out quantitative validation carried out on 28 images. Moreover, the piecewise affine transformation introduced for mesh initialization and adaptation shows better interphase and interpatient shape variability characterization than commonly used principal component analysis.

自动图像处理方法是高效分析心脏计算机断层扫描（CT）扫描仪产生的大量图像数据的前提。本文介绍了一种基于模型的方法，用于从三维CT图像中全自动分割整个心脏（四个腔室、心肌和大血管）。模型自适应通过逐步增加允许变形的自由度来实现，这提高了收敛性和分割精度。首先使用广义霍夫变换的三维实现定位图像中的心脏。通过全局相似变换将模型匹配到图像来校正姿态错位。然后，通过为模型的每个解剖区域分配仿射变换来解决多隔间网格的复杂初始化问题。最后，进行可变形适应以准确匹配患者解剖结构的边界。在28幅图像上进行的留一法定量验证中，平均表面到表面误差为0.82毫米。此外，用于网格初始化和适应的分段仿射变换相比常用的主成分分析，显示了更好的相间和患者间形状变异性表征。

In this paper, we propose an automatic method to detect microaneurysms in retina photographs. Microaneurysms are the most frequent and usually the first lesions to appear as a consequence of diabetic retinopathy. So, their detection is necessary for both screening the pathology and follow up (progression measurement). Automating this task, which is currently performed manually, would bring more ob...

在本文中，我们提出了一种自动检测视网膜照片中微动脉瘤的方法。微动脉瘤是糖尿病视网膜病变中最常见且通常最先出现的病变。因此，它们的检测对于病理筛查和随访（进展测量）都是必要的。自动化这项目前手动执行的任务将带来更多...

We propose a novel method for the automatic detection and measurement of fetal anatomical structures in ultrasound images. This problem offers a myriad of challenges, including: difficulty of modeling the appearance variations of the visual object of interest, robustness to speckle noise and signal dropout, and large search space of the detection procedure. Previous solutions typically rely on the...

我们提出了一种新方法，用于在超声图像中自动检测和测量胎儿解剖结构。这个问题带来了诸多挑战，包括：对感兴趣视觉对象外观变化建模的困难、对斑点噪声和信号丢失的鲁棒性，以及检测过程的大搜索空间。先前的解决方案通常依赖于...

Diffusion tensor magnetic resonance imaging (DT-MRI) permits the noninvasive assessment of tissue microstructure and, with fibre-tracking algorithms, allows for the 3-D trajectories of white matter fasciculi to be reconstructed noninvasively. Probabilistic algorithms allow one to assign a ldquoconfidencerdquo to a given reconstructed pathway - but often rely on a priori assumptions about sources o...

扩散张量磁共振成像（DT-MRI）允许非侵入性评估组织微观结构，并通过纤维追踪算法，可以非侵入性地重建白质纤维束的3D轨迹。概率算法允许对给定的重建路径赋予“置信度”——但通常依赖于关于源的先验假设...

In this paper, we analyze the physical basis for elasticity imaging of the breast by measuring breast skin stress patterns that result from a force sensor array pressed against the breast tissue. Temporal and spatial changes in the stress pattern allow detection of internal structures with different elastic properties and assessment of geometrical and mechanical parameters of these structures. The...

本文分析了乳房弹性成像的物理基础，通过测量由力传感器阵列按压乳房组织产生的乳房皮肤应力模式。应力模式的时间和空间变化可以检测具有不同弹性的内部结构，并评估这些结构的几何和力学参数。

We introduce a novel algorithm for the design of fast slice-selective spatially-tailored magnetic resonance imaging (MRI) excitation pulses. This method, based on sparse approximation theory, uses a second-order cone optimization to place and modulate a small number of slice-selective sinc-like radio-frequency (RF) pulse segments (“spokes”) in excitation $k$-space, enforcing sparsity on the numbe...

我们提出了一种新颖的算法，用于设计快速切片选择性空间定制的磁共振成像（MRI）激发脉冲。该方法基于稀疏近似理论，利用二阶锥优化在激发k空间中放置和调制少量切片选择性sinc-like射频（RF）脉冲段（“辐条”），强制稀疏性在脉冲数量上...

Blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) is conventionally done by reconstructing T2 * -weighted images. However, since the images are unitless they are nonquantifiable in terms of important physiological parameters. An alternative approach is to reconstruct R2 * maps which are quantifiable and have comparable BOLD contrast as T2* -weighted images. However, ...

血氧水平依赖（BOLD）功能磁共振成像（fMRI）通常通过重建T2*加权图像来完成。然而，由于这些图像是无量纲的，它们在重要生理参数方面无法量化。另一种方法是重建R2*图，这些图是可量化的，并且具有与T2*加权图像相当的BOLD对比度。然而，...

This paper investigates data compression methods for time-of-flight (TOF) positron emission tomography (PET), which rebin the 3-D TOF measurements into a set of 2-D TOF data for a stack of transaxial slices. The goal of this work is to develop re- binning algorithms that are more accurate than the TOF single- slice-rebinning (TOF-SSRB) method proposed by Mullani in 1982. Two approaches are explore...

本文研究了飞行时间（TOF）正电子发射断层扫描（PET）的数据压缩方法，该方法将三维TOF测量数据重排为一组二维TOF数据，用于一系列横断层面。本工作的目标是开发比Mullani在1982年提出的TOF单切片重排（TOF-SSRB）方法更精确的重排算法。探索了两种方法...

Ankylosing Spondylitis is a disease characterized by abnormal bone structures (syndesmophytes) growing at intervertebral disk spaces. Because this growth is so slow as to be undetectable on plain radiographs taken over years, it is desirable to resort to computerized techniques to complement qualitative human judgment with precise quantitative measures. We developed an algorithm with minimal user ...

强直性脊柱炎是一种以椎间盘间隙异常骨结构（骨赘）生长为特征的疾病。由于这种生长非常缓慢，以至于在多年拍摄的平片上无法检测到，因此需要借助计算机技术，用精确的定量测量来补充定性的人类判断。我们开发了一种算法，只需最少的用户...

Distal locking is one of the most difficult steps in intramedullary nailing. Numerous methods can help the surgeon, but all are time-consuming and involve much irradiation. We have developed and tested a new method based on only two fluoroscopic shots that do not need to be taken in the axes of the holes. This avoids requiring the presence of an experienced fluoroscopy operator to accurately adjus...

远端锁定是髓内钉置入中最困难的步骤之一。多种方法可帮助外科医生，但所有方法都耗时且涉及大量辐射。我们开发并测试了一种新方法，该方法仅基于两幅无需在钉孔轴线上拍摄的透视图像。这避免了需要经验丰富的透视操作员来精确调整...

Current density impedance imaging (CDII) is a new impedance imaging technique that can noninvasively measure the conductivity distribution inside a medium. It utilizes current density vector measurements which can be made using a magnetic resonance imager (MRI) (Scott et al., 1991). CDII is based on a simple mathematical expression for nablasigma/sigma = nabla ln sigma, the gradient of the logarit...

电流密度阻抗成像（CDII）是一种新的阻抗成像技术，可以无创地测量介质内部的电导率分布。它利用电流密度矢量测量，这些测量可以通过磁共振成像仪（MRI）进行（Scott等人，1991）。CDII基于一个简单的数学表达式：∇σ/σ = ∇lnσ，即对数的梯度...

A method is presented for the analysis of dynamic positron emission tomography (PET) data using sparse Bayesian learning. Parameters are estimated in a compartmental framework using an over-complete exponential basis set and sparse Bayesian learning. The technique is applicable to analyses requiring either a plasma or reference tissue input function and produces estimates of the system's macro-par...

提出了一种使用稀疏贝叶斯学习分析动态正电子发射断层扫描（PET）数据的方法。在房室模型框架下，使用过完备指数基集和稀疏贝叶斯学习估计参数。该技术适用于需要血浆或参考组织输入函数的分析，并产生系统宏观参数的估计...

New complex tissue microstructure estimators have been presented recently in order to elucidate white matter fibre orientations. Since these algorithms are based on the diffusion- weighted signal profile, the estimations are affected by noise artefacts. The proven robustness of these methods cannot counteract distortions since the statistical Rician behavior has not been taken into account. In thi...

最近提出了新的复杂组织微观结构估计器，以阐明白质纤维方向。由于这些算法基于扩散加权信号剖面，估计受到噪声伪影的影响。这些方法已被证明的鲁棒性无法抵消失真，因为未考虑统计上的Rician行为。在此…

Most X-ray tubes comprise a rotating anode that is bombarded with electrons to produce X-rays. A substantial amount of heat is generated, and to increase the area of the anode exposed to the electrons, without increasing the apparent size of the focal spot, the focal track of the anode is generally beveled with a very shallow angle (typically 5deg-7deg in a computed tomography (CT) tube). Due to t...

大多数X射线管包含一个旋转阳极，电子轰击阳极产生X射线。会产生大量热量，为了增加阳极暴露于电子的面积而不增加焦斑的表观尺寸，阳极的焦轨通常以非常浅的角度（在计算机断层扫描（CT）管中通常为5°-7°）倾斜。由于...

Fiducial tracking is a common target tracking method widely used in image-guided procedures such as radiotherapy and radiosurgery. In this paper, we present a multifiducial identification method that incorporates context information in the process. We first convert the problem into a state sequence problem by establishing a probabilistic framework based on a hidden Markov model (HMM), where prior ...

基准跟踪是一种常用的目标跟踪方法，广泛应用于放射治疗和放射外科等图像引导过程中。在本文中，我们提出了一种在过程中结合上下文信息的多基准识别方法。我们首先通过建立基于隐马尔可夫模型（HMM）的概率框架将问题转化为状态序列问题，其中先验...

Binary coding of multiplexed signals and images has been studied in the context of spectroscopy with models of either purely constant or purely proportional noise, and has been shown to result in improved noise performance under certain conditions. We consider the case of mixed noise in an imaging system consisting of multiple individually-controllable sources (X-ray or near-infrared, for example)...

在仅考虑恒定噪声或仅考虑比例噪声的模型下，多路复用信号和图像的二进制编码已在光谱学中得到研究，并表明在某些条件下能改善噪声性能。我们考虑成像系统中混合噪声的情况，该系统由多个独立可控的源（例如X射线或近红外）组成……

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