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The prime motivation of this work is to devise techniques that make the algebraic reconstruction technique (ART) and related methods more efficient for routine clinical use, while not compromising their accuracy. Since most of the computational effort of ART is spent for projection/backprojection operations, the authors first seek to optimize the projection algorithm. Existing projection algorithm...

这项工作的主要动机是设计技术，使代数重建技术（ART）及相关方法在日常临床使用中更加高效，同时不降低其准确性。由于ART的大部分计算工作量用于投影/反投影操作，作者首先寻求优化投影算法。现有的投影算法...

In medical imaging it is common to reconstruct dense motion estimates, from sparse measurements of that motion, using some form of elastic spline (thin-plate spline, snakes and other deformable models, etc.). Usually the elastic spline uses only bending energy (second-order smoothness constraint) or stretching energy (first-order smoothness constraint), or a combination of the two. These elastic s...

在医学成像中，通常使用某种形式的弹性样条（薄板样条、蛇模型和其他可变形模型等）从稀疏的运动测量中重建稠密的运动估计。通常弹性样条只使用弯曲能量（二阶平滑约束）或拉伸能量（一阶平滑约束），或两者的组合。这些弹性...

We give a new algorithm for reconstructing a density f in the plane from its projections along those lines making an angle greater than a fixed δ > 0 with the x axis. Of course, the performance of the algorithm depends on δ and on the smoothness of f, but it appears to give a practical and simple solution to the problem whenever one exists. The basic idea, which seems to be new, is to make an affi...

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It is observed that when the homogeneity property of the ramp filter is used to derive a filtered backprojection algorithm in fan-beam tomography, the reconstructed images have nonstationary frequency components and nonstationary noise. When a short focal-length is used, higher frequency components are amplified more at the edge of the image than at the center of the image, resulting in higher noi...

观察到在扇束断层扫描中，利用斜坡滤波器的同质性推导滤波反投影算法时，重建图像具有非平稳的频率分量和非平稳噪声。使用短焦距时，图像边缘的高频分量比中心放大更多，导致更高噪声...

We present a novel algorithm for reconstructing interferograms acquired in optical frequency domain imaging (OFDI). The algorithm was developed specifically for processing in field programmable gate arrays (FPGAs) and featured the use of a finite-impulse-response (FIR) filter implementation of B-spline interpolation for efficiently re-sampling $k$-space. When implemented in FPGAs, the algorithm al...

我们提出了一种新颖的算法，用于重建在光学频域成像（OFDI）中获取的干涉图。该算法专门为现场可编程门阵列（FPGA）中的处理而开发，其特点是使用有限脉冲响应（FIR）滤波器实现的B样条插值，以高效地重新采样k空间。当在FPGA中实现时，该算法...

Computational methods can be used to provide an initial screening or a second opinion in medical settings and may improve the sensitivity and specificity of diagnoses. In the current study, linear discriminant models and artificial neural networks are trained to detect breast cancer in suspicious masses using radiographic features and patient age. Results on 139 suspicious breast masses (79 malign...

计算方法可用于在医疗环境中提供初步筛查或第二意见，并可能提高诊断的敏感性和特异性。在本研究中，使用放射学特征和患者年龄训练线性判别模型和人工神经网络，以检测可疑肿块中的乳腺癌。对139个可疑乳腺肿块（79个恶性...）的结果...

Recently, an iterative reconstruction-reprojection (IRR) algorithm has been suggested for application to limited view computed tomography (CT). In the IRR, the interpolation operation is performed in the object space during backprojection-reprojection. The errors associated with the interpolation degrade the reconstructed image and may cause divergence unless a large number of rays is used. In thi...

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At the advent of multislice computed tomography (CT) a variety of approximate cone-beam algorithms have been proposed suited for reconstruction of small cone-angle CT data in a spiral mode of operation. The goal of this study is to identify a practical and efficient approximate cone-beam method, extend its potential for medical use, and demonstrate its performance at medium cone-angles required fo...

随着多层计算机断层扫描（CT）的出现，提出了多种适用于螺旋模式下小锥角CT数据重建的近似锥束算法。本研究旨在确定一种实用且高效的近似锥束方法，扩展其在医学应用中的潜力，并展示其在中等锥角（医学所需）下的性能...

An algorithm for the automatic contour detection of objects in CT images is presented. It requires little memory space, allows easy incorporation of different types of local digital filters, and is fast. Typical computation time with a minicomputer is less than one second. An implementation of the algorithm for the detection of bone contours from low dose CT images is given as an example.

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For pt. I see ibid., vol. 19, no. 9, p. 822-34 (2000). The recently introduced multislice data acquisition for computed tomography (CT) is based on multirow detector design, increased rotation speed, and advanced z-interpolation and z-filtering algorithms. The authors evaluated slice sensitivity profiles (SSPs) and noise of a clinical multislice spiral CT (MSCT) scanner with M=4 simultaneously acq...

参见第一部分（同上，卷19，第9期，第822-34页，2000年）。最近引入的用于计算机断层扫描（CT）的多层数据采集基于多排探测器设计、增加的旋转速度以及先进的z插值和z滤波算法。作者评估了具有同时采集M=4排的临床多层螺旋CT（MSCT）扫描仪的切片敏感度轮廓（SSP）和噪声...

Image processing was used as a fundamental tool to derive motion information from magnetic resonance (MR) images, which was fed back into prospective respiratory motion correction during subsequent data acquisition to improve image quality in coronary MR angiography (CMRA) scans. This reduces motion artifacts in the images and, in addition, enables the usage of a broader gating window than commonl...

图像处理被用作从磁共振（MR）图像中提取运动信息的基本工具，这些信息被反馈到后续数据采集过程中的前瞻性呼吸运动校正中，以改善冠状MR血管造影（CMRA）扫描的图像质量。这减少了图像中的运动伪影，此外，还允许使用比通常更宽的门控窗口...

A review is made of selected recent publications on three-dimensional image reconstruction for PET. A new algorithm is proposed which is designed to fully utilize all emitted gamma rays which can be detected in a truncated spherical detector. By such full utilization of emitted rays the new algorithm should produce images of better statistical accuracy than could be produced by previously known al...

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A new class of interpolation kernels that are locally compact in signal space and "almost band-limited" in Fourier space is presented. The kernels are easy to calculate and lend themselves to problems in which the kernels must be analytically manipulated with other operations or operators such as convolutions and projection integrals. The interpolation kernels are comprised of a linear sum of a Ga...

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In this paper we analyze a result previously published about a comparison between two statistical tests used for evaluation of boundary detection algorithms on medical images. We conclude that the statement made by Chalana and Kim (1997) about the performance of the percentage test has a weak theoretical foundation, and according to our results, is not correct. In addition, we propose a one-sided ...

本文分析了一个先前发表的结果，该结果比较了两种用于评估医学图像边界检测算法的统计检验。我们得出结论，Chalana和Kim（1997）关于百分比检验性能的论述理论基础薄弱，并且根据我们的结果，该论述是不正确的。此外，我们提出了一种单侧...

The order in which the projections are applied in the algebraic reconstruction technique (ART) has a great effect on speed of convergence, accuracy, and the amount of noise-like artifacts in the reconstructed image. In this paper, a new projection ordering scheme for ART is presented: the weighted-distance scheme (WDS). It heuristically optimizes the angular distance of a newly selected projection...

在代数重建技术（ART）中，投影的应用顺序对收敛速度、精度以及重建图像中类似噪声的伪影数量有显著影响。本文提出了一种新的ART投影排序方案：加权距离方案（WDS）。它启发式地优化新选投影的角度距离...

A general mathematical formalism for generating multiparametric NMR image encoding gradients is introduced. The new schematic approach enables one to construct any desired encoding gradient which may be used in an imaging sequence. Basic gradient waveforms which can be used as building blocks of the desired encoding gradients are presented. A matrix operator for obtaining the encoding gradient for...

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The methods of Bayesian statistics are applied to the analysis of fMRI data, Three specific models are examined. The first is the familiar linear model with white Gaussian noise. In this section, the Jeffreys' Rule for noninformative prior distributions is stated and it is shown how the posterior distribution may be used to infer activation in individual pixels. Next, linear time-invariant (LTI) s...

贝叶斯统计方法应用于fMRI数据分析。考察了三个特定模型。第一个是带有白高斯噪声的常见线性模型。在这一部分，介绍了无信息先验分布的杰弗里斯规则，并展示了如何使用后验分布来推断单个像素的激活。接下来，线性时不变（LTI）...

This paper demonstrates a time-saving, automated method that helps to segment the lateral ventricles and caudate nucleus in T1-weighted coronal magnetic resonance (MR) brain images of normal control subjects. The method involves choosing intensity thresholds by using anatomical information and by locating peaks in histograms. To validate the method, the lateral ventricles and caudate nucleus were ...

本文展示了一种省时、自动化的方法，有助于在正常对照受试者的T1加权冠状磁共振（MR）脑图像中分割侧脑室和尾状核。该方法通过利用解剖信息和定位直方图中的峰值来选择强度阈值。为了验证该方法，侧脑室和尾状核被...

The classical principal-axes transformation (PAT) has been used in numerous publications for three-dimensional (3-D) reconstructions by sequential alignment of histological sections. However, the PAT can determine at most 1/2n(n+1) parameters (scaling-rotation) in n dimensions. Distortions (shearing) of histological sections can be described by an affine transformation with n/sup 2/ parameters. An...

经典的主轴线变换（PAT）已被广泛用于通过组织学切片的连续对齐进行三维（3-D）重建。然而，PAT最多只能确定n维中的1/2n(n+1)个参数（缩放-旋转）。组织学切片的畸变（剪切）可以用具有n^2个参数的仿射变换来描述。

Discusses the inclusion of anatomical constraints and anisotropy in static Electrical Impedance Tomography (EIT) using a two-step approach to EIT. In the first step, the boundaries between regions of different conductivities are anatomically constrained using Magnetic Resonance Imaging (MRI) data. In the second step, the conductivity values in different regions are determined. Anisotropic conducti...

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It is argued that positron annihilation into three photons, although quite rare, could still be used as a new imaging modality of positron emission tomography. The information gained when the three decay photons are detected is significantly higher than in the case of 511 keV two-gamma annihilation. The performance of three-gamma imaging in terms of the required detector properties, spatial resolu...

有人认为，正电子湮灭成三个光子虽然相当罕见，但仍可被用作正电子发射断层扫描的一种新的成像模式。当检测到三个衰变光子时，获得的信息明显高于511 keV双伽马湮灭的情况。三伽马成像在所需探测器特性、空间分辨率等方面的性能...

Magnetic resonance (MR) tagging has been shown to be a useful technique for noninvasively measuring the deformation of an in vivo heart. An important step in analyzing tagged images is the identification of tag lines in each image of a cine sequence. Most existing tag identification algorithms require user defined myocardial contours. Contour identification, however, is time consuming and requires...

磁共振（MR）标记已被证明是一种非侵入性测量活体心脏变形的有用技术。分析标记图像的一个重要步骤是识别电影序列中每幅图像中的标记线。大多数现有的标记识别算法需要用户定义的心肌轮廓。然而，轮廓识别耗时且需要...

Bronchiolar obstruction is commonly manifested in computed tomography (CT) images as areas of decreased attenuation relative to adjacent normal lung parenchyma. The certain identification of such areas is difficult in practice, particularly if they are poorly marginated. This paper presents a novel approach to the enhancement of feature differences between normal and diseased lung parenchyma so th...

细支气管阻塞在计算机断层扫描（CT）图像上通常表现为相对于邻近正常肺实质的衰减减低区域。实际中，这类区域的确切识别很困难，尤其是当它们边缘不清时。本文提出了一种新方法，用于增强正常与病变肺实质之间的特征差异，以便...

Recently, foundations rooted in physics have been laid down for the goal of simulating the propagation of a guide wire inside the vasculature. At the heart of the simulation lies the fundamental task of energy minimization. The energy comes from interaction with the vessel wall and the bending of the guide wire. For the simulation to be useful in actual training, obtaining the smallest possible op...

最近，为了模拟导丝在血管内的传播这一目标，已经奠定了基于物理学的基础。模拟的核心是能量最小化这一基本任务。能量来自与血管壁的相互作用以及导丝的弯曲。为了使模拟在实际训练中有用，需要获得尽可能小的操作...

A technique determines the optimal window width for orbiting rod transmission studies in positron emission tomography (PET). Windowing reduces noise in orbiting rod transmission studies. Lines-of-response (LOR) which intersect the rods generate primarily true coincidence events. LOR which pass far from the rods generate random and scatter events. Since the angular position of the orbiting rods is ...

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