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This paper outlines a simple, fast, and accurate method for automatically locating the nipple on digitized mammograms that have been segmented to reveal the skin-air interface. If the average gradient of the intensity is computed in the direction normal to the interface and directed inside the breast, it is found that there is a sudden and distinct change in this parameter close to the nipple. A n...

本文概述了一种简单、快速且准确的方法，用于在已分割以显示皮肤-空气界面的数字化乳腺X线照片上自动定位乳头。如果计算垂直于界面方向并指向乳房内部的平均强度梯度，就会发现该参数在乳头附近发生突然而明显的变化。一

Respiratory motion during the collection of computed tomography (CT) projections generates structured artifacts and a loss of resolution that can render the scans unusable. This motion is problematic in scans of those patients who cannot suspend respiration, such as the very young or intubated patients. Here, the authors present an algorithm that can be used to reduce motion artifacts in CT scans ...

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Methods of quantitative emission computed tomography require compensation for linear photon attenuation. A current trend in single-photon emission computed tomography (SPECT) and positron emission tomography (PET) is to employ transmission scanning to reconstruct the attenuation map. Such an approach, however, considerably complicates both the scanner design and the data acquisition protocol. A dr...

定量发射计算机断层扫描方法需要对线性光子衰减进行补偿。当前单光子发射计算机断层扫描（SPECT）和正电子发射断层扫描（PET）的一个趋势是使用透射扫描来重建衰减图。然而，这种方法大大复杂化了扫描仪设计和数据采集协议。一个...

In magnetic resonance imaging (MRI), the spatial inhomogeneity of the static magnetic field can cause degraded images if the reconstruction is based on inverse Fourier transformation. This paper presents and discusses a range of fast reconstruction algorithms that attempt to avoid such degradation by taking the field inhomogeneity into account. Some of these algorithms are new, others are modified...

在磁共振成像（MRI）中，如果重建基于逆傅里叶变换，静态磁场的空间不均匀性可能导致图像质量下降。本文介绍并讨论了一系列快速重建算法，这些算法通过考虑场不均匀性来避免这种退化。其中一些算法是新的，另一些则是经过改进的...

Presents two new methods for robust parameter estimation of mixtures in the context of magnetic resonance (MR) data segmentation. The head is constituted of different types of tissue that can be modeled by a finite mixture of multivariate Gaussian distributions. The authors' goal is to estimate accurately the statistics of desired tissues in presence of other ones of lesser interest. These latter ...

针对磁共振（MR）数据分割中的混合模型，提出了两种新的鲁棒参数估计方法。头部由不同类型的组织构成，这些组织可以用多元高斯分布的有限混合来建模。作者的目标是在存在其他不太感兴趣的组织的情况下，准确估计所需组织的统计量。这些后者……

In this paper implicit representations of deformable models for medical image enhancement and segmentation are considered. The advantage of implicit models over classical explicit models is that their topology can be naturally adapted to objects in the scene. A geodesic formulation of implicit deformable models is especially attractive since it has the energy minimizing properties of classical mod...

本文考虑用于医学图像增强和分割的可变形模型的隐式表示。隐式模型相对于经典显式模型的优势在于其拓扑结构可以自然地适应场景中的物体。隐式可变形模型的测地线公式尤其吸引人，因为它具有经典模型的能量最小化特性……

A new implementation of the minimum spanning tree (MST) phase unwrapping method is presented. The time complexity of the MST method is reduced from O(n/sup 2/) to O(n log/sub 2/ n), where n is the number of pixels in the phase map. Typical 256/spl times/256 phase maps from magnetic resonance imaging can be unwrapped in seconds, compared with tens of minutes with the O(n/sup 2/) implementation. Thi...

提出了一种新的最小生成树（MST）相位展开方法的实现。该方法的时间复杂度从O(n²)降低到O(n log₂ n)，其中n是相位图中的像素数。典型的256×256磁共振相位图可以在几秒内展开，而O(n²)的实现则需要几十分钟。

The authors have applied mathematical morphology for fractal analysis on bone X-ray images. The digitized gray level image is treated as a three-dimensional surface whose fractal dimension is calculated by performing a series of dilations on this surface and plotting the area of the resulting set of surfaces against the size of the structuring element. This approach has the added advantage of enco...

中文摘要翻译待生成

The gain achieved in image quality by utilizing, in the image forming process, the time-of-flight information (TOF) of positron annihilation photons between their inception and detection was measured experimentally by means of a positron emission tomograph (PET)-Super PETT I. The measurements were carried out by imaging a 35 cm cylindrical uniform phantom containing different positron activity con...

中文摘要翻译待生成

In this paper a temporal learning-filtering procedure is applied to refine the left ventricle (LV) boundary detected by an active-contour model. Instead of making prior assumptions about the LV shape or its motion, this information is incrementally gathered directly from the images and is exploited to achieve more coherent segmentation. A Hough transform technique is used to find an initial approx...

本文应用时间学习-滤波程序来优化由主动轮廓模型检测到的左心室（LV）边界。不是对LV形状或运动做出先验假设，而是直接从图像中逐步收集这些信息，并利用它们实现更一致的分割。使用霍夫变换技术来找到初始近似...

It is well understood that binary classifiers have two implicit objective functions (sensitivity and specificity) describing their performance. Traditional methods of classifier training attempt to combine these two objective functions (or two analogous class performance measures) into one so that conventional scalar optimization techniques can be utilized. This involves incorporating a priori inf...

众所周知，二元分类器有两个隐含的目标函数（灵敏度和特异度）来描述其性能。传统的分类器训练方法试图将这两个目标函数（或两个类似的类别性能度量）合并为一个，以便使用传统的标量优化技术。这涉及引入先验信息...

For newly developed iterative Newton-Kantorovitch reconstruction techniques, the quality of the final image depends on both experimental and model noise. Experimental noise is inherent to any experimental acquisition scheme, while model noise refers to the accuracy of the numerical model, used in the reconstruction process, to reproduce the experimental setup. This paper provides a systematic asse...

对于新发展的迭代牛顿-坎托罗维奇重建技术，最终图像的质量取决于实验噪声和模型噪声。实验噪声是任何实验采集方案固有的，而模型噪声指的是重建过程中用于再现实验设置的数值模型的精度。本文提供了一种系统的评估...

Localization ROC (LROC) observer studies examined whether detector response compensation (DRC) in ordered-subset, expectation-maximization (OSEM) reconstructions helps in the detection and localization of hot tumors. Simulated gallium (Ga-67) images of the thoracic region were used in the study. The projection data modeled the acquisition of attenuated 93- and 185-keV photons with a medium-energy ...

局部化ROC（LROC）观察者研究考察了在有序子集期望最大化（OSEM）重建中进行探测器响应补偿（DRC）是否有助于检测和定位热肿瘤。研究中使用了模拟的胸部区域镓（Ga-67）图像。投影数据模拟了中能准直器下93 keV和185 keV衰减光子的采集。

Large-tip-angle multidimensional radio-frequency (RF) pulse design is a difficult problem, due to the nonlinear response of magnetization to applied RF at large tip-angles. In parallel excitation, multidimensional RF pulse design is further complicated by the possibility for transmit field patterns to change between subjects, requiring pulses to be designed rapidly while a subject lies in the scan...

大翻转角多维射频（RF）脉冲设计是一个难题，因为在大翻转角下磁化对施加RF的响应是非线性的。在并行激励中，由于发射场模式可能在不同受试者之间变化，需要受试者在扫描过程中快速设计脉冲，这使得多维RF脉冲设计更加复杂。

A statistical method for detecting activated pixels in functional MRI (fMRI) data is presented. In this method, the fMRI time series measured at each pixel is modeled as the sum of a response signal which arises due to the experimentally controlled activation-baseline pattern, a nuisance component representing effects of no interest, and Gaussian white noise. For periodic activation-baseline patte...

提出了一种用于检测功能磁共振成像（fMRI）数据中激活像素的统计方法。在该方法中，每个像素处的fMRI时间序列被建模为响应信号（由实验控制的激活-基线模式引起）、不感兴趣的干扰效应和高斯白噪声之和。对于周期性激活-基线模式...

Fractal analysis of bone X-ray images has received much interest recently for the diagnosis of bone disease. Here, the authors propose a fractal analysis of bone X-ray tomographic microscopy (XTM) projections. The aim of the study is to establish whether or not there is a correlation between three-dimensional (3-D) trabecular changes and two-dimensional (2-D) fractal descriptors. Using a highly co...

骨X射线图像的分形分析近来在骨病诊断中受到广泛关注。本文作者提出对骨X射线断层显微镜（XTM）投影进行分形分析。研究旨在确定三维（3-D）小梁变化与二维（2-D）分形描述符之间是否存在相关性。利用高度共...

Cochlear implantation is the standard treatment for profound hearing loss, Preimplantation and postimplantation spiral computed tomography (CT) is essential in several key clinical and research aspects. The maximum image resolution with commercial spiral CT scanners is insufficient to define clearly anatomical features and implant electrode positions in the inner ear, In this paper, the authors de...

人工耳蜗植入是治疗重度听力损失的标准方法，术前和术后螺旋计算机断层扫描（CT）在多个关键的临床和研究方面至关重要。商用螺旋CT扫描仪的最大图像分辨率不足以清晰定义内耳的解剖结构和植入电极位置。在本文中，作者...

The authors present a new algorithm to enhance the edges and contrast of chest and breast radiographs while minimally amplifying image noise. The algorithm consists of a linear combination of an original image and two smoothed images obtained from it by using different masks and parameters, followed by the application of nonlinear contrast stretching. The result is an image which retains the high ...

中文摘要翻译待生成

A technique is presented for automatic detection of the longitudinal fissure in tomographic scans of the brain. The technique utilizes the planar nature of the fissure and is a three-dimensional variant of the Hough transform principle. Algorithmic and computational aspects of the technique are discussed. Results and performance on coronal and transaxial magnetic resonance data show that the algor...

中文摘要翻译待生成

Active model-based segmentation has frequently been used in medical image processing with considerable success. Although the active model-based method was initially viewed as an optimization problem, most researchers implement it as a partial differential equation solution. The advantages and disadvantages of the active model-based method are distinct: speed and stability. To improve its performan...

基于活动模型的图像分割在医学图像处理中经常被使用，并取得了相当大的成功。尽管基于活动模型的方法最初被视为优化问题，但大多数研究人员将其实现为偏微分方程解。基于活动模型的方法的优缺点很明显：速度和稳定性。为了提高其性能...

We present a new approach to anisotropic diffusion based on a multidirectional diffusion flux. The diffusion flux is decomposed in an orthogonal basis, effectively enabling enhancement of contours as well as diffusion along the contours. To this end, we have selected a three-dimensional basis that depicts the directions of principal curvature and has an interesting interpretation in the context of the vessels. The diffusion function associated to each vector of the basis depends on the first-order derivative of the intensity in this direction, instead of the traditional norm of the smoothed gradient. Accordingly, we present the results of a restoration of computed tomography data of the liver.

我们提出了一种基于多方向扩散通量的各向异性扩散新方法。扩散通量在正交基上分解，有效地实现了轮廓增强以及沿轮廓的扩散。为此，我们选择了一个三维基，该基描述了主曲率方向，并在……背景下具有有趣的解释。

The problem of reconstruction in positron emission tomography (PET) is basically estimating the number of photon pairs emitted from the source. Using the concept of the maximum-likelihood (ML) algorithm, the problem of reconstruction is reduced to determining an estimate of the emitter density that maximizes the probability of observing the actual detector count data over all possible emitter dens...

中文摘要翻译待生成

A new imaging modality is introduced to image electrical conductivity of biological tissues via contactless measurements. This modality uses magnetic excitation to induce currents inside the body and measures the magnetic fields of the induced currents. In this study, the mathematical basis of the methodology is analyzed and numerical models are developed to simulate the imaging system. The induce...

介绍了一种新的成像模态，通过非接触测量对生物组织的电导率进行成像。该模态利用磁激励在体内感应电流，并测量感应电流产生的磁场。本研究分析了该方法的数学基础，并开发了数值模型来模拟成像系统。感应...

Accurate detection of vessel boundaries is particularly important for a precise extraction of vasculatures in magnetic resonance angiography (MRA). In this paper, we propose the use of weighted local variance (WLV)-based edge detection scheme for vessel boundary detection in MRA. The proposed method is robust against changes of intensity contrast of edges and capable of giving high detection respo...

准确检测血管边界对于磁共振血管成像（MRA）中血管的精确提取尤为重要。本文提出使用基于加权局部方差（WLV）的边缘检测方案用于MRA中的血管边界检测。该方法对边缘强度对比度的变化具有鲁棒性，并且能够给出高检测响应...

Considers the direct Fourier methods (DFM's) for reconstructing an image from its given X-ray projections. The main purpose here is to use concepts from numerical analysis to estimate the errors in the methods. The authors also suggest an alternative to the interpolations involved in the DFM's and estimate the number of terms involved. Realizing that one of the main reasons for the degradation of ...

考虑使用直接傅里叶方法（DFM）从给定的X射线投影重建图像。这里的主要目的是使用数值分析的概念来估计方法中的误差。作者还提出了DFM中涉及的插值的替代方案，并估计了涉及的项数。意识到...