Popular Articles

A method for the automatic measurement of femur length in fetal ultrasound images is presented. Fetal femur length measurements are used to estimate gestational age by comparing the measurement to a typical growth chart. Using a real-time ultrasound system, sonographers currently indicate the femur endpoints on the ultrasound display station with a mouse-like device. The measurements are subjectiv...

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Mixture models are commonly used in the statistical segmentation of images. For example, they can be used for the segmentation of structural medical images into different matter types, or of statistical parametric maps into activating and nonactivating brain regions in functional imaging. Spatial mixture models have been developed to augment histogram information with spatial regularization using ...

混合模型常用于图像的统计分割。例如，它们可用于将结构医学图像分割成不同的物质类型，或将统计参数图分割为功能成像中的激活和非激活脑区域。空间混合模型已被开发出来，通过空间正则化增强直方图信息，使用...

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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The new spiral multislice computed tomography (CT) scanners and the significant increase in rotation speed offer great potential for cardiac imaging with X-ray CT. The authors have therefore developed the dedicated cardiac reconstruction algorithms 180/spl deg/ multislice cardio interpolation (MCI) and 180/spl deg/ multislice cardio delta (MCD) and here offer further details and validation. The al...

新型螺旋多层计算机断层扫描（CT）扫描仪以及旋转速度的显著提高为X射线CT心脏成像提供了巨大潜力。因此，作者开发了专门的心脏重建算法180°多层心脏插值（MCI）和180°多层心脏delta（MCD），并在此提供进一步的细节和验证。该算...

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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Examines the use of the algebraic reconstruction technique (ART) and related techniques to reconstruct 3-D objects from a relatively sparse set of cone-beam projections. Although ART has been widely used for cone-beam reconstruction of high-contrast objects, e.g., in computed angiography, the work presented here explores the more challenging low-contrast case which represents a little-investigated...

研究了使用代数重建技术（ART）及相关技术从相对稀疏的锥束投影中重建三维物体。尽管ART已广泛应用于高对比度物体的锥束重建，例如在计算机断层血管造影中，但本文探讨了更具挑战性的低对比度情况，这是一个研究较少的领域。

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）...

Gastrointestinal (GI) tract examination with spiral/helical computed tomography (CT) is currently performed by slice-based inspection of axial images. CT colography is a recent advance which allows an intraluminal visualization of the colon, similar to endoscopy. Various rendering algorithms have been developed with promising results, however navigation through the complex, tortuous anatomy of the...

目前，螺旋/螺旋计算机断层扫描（CT）检查胃肠道是通过逐层检查轴向图像进行的。CT结肠成像是一项最新进展，它允许像内窥镜检查一样对结肠进行腔内可视化。已经开发了各种渲染算法，并取得了有希望的结果，然而在复杂、曲折的解剖结构中导航……

Single photon emission computed tomography (SPECT) imaging with /sup 201/Tl or /sup 99m/Tc agent is used to assess the location or the extent of myocardial infarction or ischemia. A method is proposed to decrease the effect of operator variability in the visual or quantitative interpretation of scintigraphic myocardial perfusion studies. To effect this, the patient's myocardial images (target case...

使用/sup 201/Tl或/sup 99m/Tc试剂的单光子发射计算机断层扫描(SPECT)成像用于评估心肌梗死或缺血的位置或程度。提出了一种方法以减少操作员变异性在闪烁心肌灌注研究的视觉或定量解释中的影响。为了实现这一点，患者的心肌图像(目标病例...)

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...

A new class of acquisition schemes for helical cone-beam computed tomography (CB-CT) scanning is introduced, and their effect on the reconstruction methods is analyzed. These acquisition schemes are based on a new detector shape that is bounded by the helix. It will be shown that the data acquired with these schemes are compatible with exact reconstruction methods, and the adaptation of exact reco...

介绍了一类用于螺旋锥束计算机断层扫描（CB-CT）的新型采集方案，并分析了它们对重建方法的影响。这些采集方案基于一种由螺旋线界定的新型探测器形状。将证明这些方案采集的数据与精确重建方法兼容，并且精确重建方法的适应...

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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This paper addresses the long object problem in helical cone-beam computed tomography. The authors present the PHI-method, a new algorithm for the exact reconstruction of a region-of-interest (ROI) of a long object from axially truncated data extending only slightly beyond the ROI. The PHI-method is an extension of the Radon-method, published by Kudo et al. in Phys. in Med. and Biol., vol. 43, p. ...

本文解决了螺旋锥束计算机断层扫描中的长物体问题。作者提出了PHI方法，这是一种新算法，用于从仅略超出感兴趣区域（ROI）的轴向截断数据中精确重建长物体的感兴趣区域。PHI方法是Radon方法的扩展，由Kudo等人在《Phys. in Med. and Biol.》第43卷中发表。

This paper deals with an automated method for the simultaneous correction of patient motion and gray values prior to subtraction in digitized angiography. The algorithm consists of maximizing the deterministic sign change (DSC) criterion with respect to three registration parameters (two translational shifts and one constant value added to the pixel values of the image with contrast medium). This ...

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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...

Lossless compression techniques are essential in archival and communication of medical images. Here, a new segmentation-based lossless image coding (SLIC) method is proposed, which is based on a simple but efficient region growing procedure. The embedded region growing procedure produces an adaptive scanning pattern for the image with the help of a very-few-bits-needed discontinuity index map. Alo...

无损压缩技术对于医学图像的存档和通信至关重要。本文提出了一种新的基于分割的无损图像编码（SLIC）方法，该方法基于一个简单但高效的区域生长过程。嵌入的区域生长过程借助一个只需极少比特的不连续性指标图，为图像生成自适应扫描模式。

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...

The authors analyzed the noise characteristics of two-dimensional (2-D) and three-dimensional (3-D) images obtained from the GE Advance positron emission tomography (PET) scanner. Three phantoms were used: a uniform 20-cm phantom, a 3-D Hoffman brain phantom, and a chest phantom with heart and lung inserts. Using gated acquisition, the authors acquired 20 statistically equivalent scans of each pha...

作者分析了从GE Advance正电子发射断层扫描（PET）扫描仪获得的二维（2-D）和三维（3-D）图像的噪声特性。使用了三个体模：一个均匀的20厘米体模，一个3-D Hoffman脑体模，以及一个带有心脏和肺部插入物的胸部体模。使用门控采集，作者获得了每个相位的20个统计上等效的扫描...

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...

The authors propose a new 2-D point source scattering deconvolution method. The cross-plane scattering is incorporated into the algorithm by modeling a scattering point source function. In the model, the scattering dependence on axial and transaxial directions is reflected in the exponential fitting parameters, and these parameters are directly estimated from a limited number of measured point res...

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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...

Computerized analysis of the tongue surface movement can provide valuable information to speech and swallowing research. Ultrasound technology is currently the most attractive modality for the tongue imaging mainly because of its high video frame rate. However, problems with ultrasound imaging, such as noise and echo artifacts, refractions, and unrelated reflections pose significant challenges for...

舌头表面运动的计算机化分析可以为言语和吞咽研究提供有价值的信息。超声技术目前是舌头成像最具吸引力的模态，主要因为其高视频帧率。然而，超声成像的问题，如噪声和回声伪影、折射以及无关反射，给...带来了重大挑战。

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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