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A general reconstruction algorithm for magnetic resonance imaging (MRI) with gradients having arbitrary time dependence is presented. This method estimates spin density by calculating the weighted correlation of the observed free induction decay signal and the phase modulation function at each point. A theorem which states that this method can be derived from the conditions of linearity and shift ...

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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...

Parallel transmission is a very promising candidate technology to mitigate the inevitable radio-frequency (RF) field inhomogeneity in magnetic resonance imaging at ultra-high field. For the first few years, pulse design utilizing this technique was expressed as a least squares problem with crude power regularizations aimed at controlling the specific absorption rate (SAR), hence the patient safety...

平行传输是一项非常有前景的候选技术，旨在减轻超高场磁共振成像中不可避免的射频场不均匀性。在最初几年，利用该技术的脉冲设计被表述为一个最小二乘问题，并采用粗略的功率正则化来控制特定吸收率（SAR），从而确保患者安全……

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...

Images formed with endoscopes suffer from a spatial distortion due to the wide-angle nature of the endoscope's objective lens. This change in the size of objects with position precludes quantitative measurement of the area of the objects, which is important in endoscopy for accurately measuring ulcer and lesion sizes over time. A method for correcting the distortion characteristic of endoscope ima...

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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...

A partial-differential equations (PDE)-based system for detecting the boundary of skin lesions in digital clinical skin images is presented. The image is first preprocessed via contrast-enhancement and anisotropic diffusion. If the lesion is covered by hairs, a PDE-based continuous morphological filter that removes them is used as an additional preprocessing step. Following these steps, the skin l...

提出了一种基于偏微分方程（PDE）的系统，用于检测数字临床皮肤图像中皮肤病变的边界。图像首先通过对比度增强和各向异性扩散进行预处理。如果病变被毛发覆盖，则使用基于PDE的连续形态学滤波器将其移除作为额外的预处理步骤。在这些步骤之后，皮肤病变...

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...

This paper presents the adaptive axial interpolator (AAI), a novel spiral interpolation approach for multislice spiral computed tomography (CT) implemented in a clinical multislice CT scanner, the SOMATOM Volume Zoom (Siemens Medical Systems, Forchheim, Germany). The method works on parallel-beam data generated from the acquired fan-beam data by azimuthal rebinning. Spiral interpolation is perform...

本文介绍了自适应轴向插值器（AAI），这是一种用于多层螺旋计算机断层扫描（CT）的新型螺旋插值方法，已在临床多层螺旋CT扫描仪SOMATOM Volume Zoom（西门子医疗系统，德国福希海姆）中实现。该方法通过对采集的扇形束数据进行方位角重排，生成平行束数据。螺旋插值执行...

Trabecular bone (TB) is a complex quasi-random network of interconnected plates and rods. TB constantly remodels to adapt to the stresses to which it is subjected (Wolff's Law). In osteoporosis, this dynamic equilibrium between bone formation and resorption is perturbed, leading to bone loss and structural deterioration. Both bone loss and structural deterioration increase fracture risk. Bone's me...

松质骨是一个由相互连接的板状和杆状结构组成的复杂准随机网络。松质骨不断重塑以适应其所承受的应力（沃尔夫定律）。在骨质疏松症中，骨形成和骨吸收之间的动态平衡被打破，导致骨质流失和结构恶化。骨质流失和结构恶化都会增加骨折风险。骨的力学...

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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The authors detail the design and implementation of HANDX, a model-based computer vision system used in the domain of medical image processing. Given a digitized hand radiograph, HANDX segments out specific bones and measures particular parameters of the bones, without requiring specific characterization of noise variations in background contrast and anatomical differences which arise from patient...

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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...

Magnetic particle imaging allows to determine the spatial distribution of magnetic nanoparticles in vivo. The system matrix in magnetic particle imaging is commonly acquired in a tedious calibration scan and requires to measure the system response at numerous positions in the field-of-view. In this paper, we propose a method that significantly reduces the number of required calibration scans. It e...

磁粒子成像能够确定体内磁性纳米颗粒的空间分布。磁粒子成像中的系统矩阵通常通过繁琐的校准扫描获取，需要在视场中的多个位置测量系统响应。在本文中，我们提出了一种显著减少所需校准扫描次数的方法。它...

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...

The noise-equivalent count-rate (NEC) performance of a neuro-positron emission tomography (PET) scanner has been determined with and without interplane septa on uniform cylindrical phantoms of differing radii and in human studies to assess the optimum count rate conditions that realize the maximum gain. In the brain, the effective gain in NEC performance for three-dimensions (3-D) ranges from >5 a...

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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...

A method is presented to interpolate between neighboring slices in a grey-scale tomographic data set. Spatial correspondence between adjacent slices is established using a nonrigid registration algorithm based on B-splines which optimizes the normalized mutual information similarity measure. Linear interpolation of the image intensities is then carried out along the directions calculated by the re...

提出了一种在灰度断层数据集中对相邻切片进行插值的方法。利用基于B样条的非刚体配准算法建立相邻切片之间的空间对应关系，该算法优化了归一化互信息相似性度量。然后沿着由配准计算出的方向对图像强度进行线性插值...

A new method to correct the barrel distortion of an electronic endoscope image is presented. A correction model assuming circularly symmetric distortion is introduced with the following model parameters: the center of distortion and the coefficients of polynomials representing the distortion correction in the radial direction. If the imaging system is distortion-free, straight lines in the object ...

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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...

Artifacts can result when reconstructing a dynamic image sequence from inconsistent, as well as insufficient and truncated, cone beam single photon emission computed tomography (SPECT) projection data acquired by a slowly rotating gantry. The artifacts can lead to biases in kinetic model parameters estimated from time-activity curves generated by overlaying volumes of interest on the images. Howev...

当从由慢速旋转机架采集的不一致、不充分且截断的锥束单光子发射计算机断层扫描（SPECT）投影数据重建动态图像序列时，可能会产生伪影。这些伪影可能导致通过将感兴趣区域叠加在图像上生成的时间-活动曲线估计的动力学模型参数出现偏差。

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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