Popular Articles

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

Evaluates a segmentation technique for magnetic resonance (MR) images of the brain based on fuzzy algorithms for learning vector quantization (FALVQ). These algorithms perform vector quantization by updating all prototypes of a competitive network through an unsupervised learning process. Segmentation of MR images is formulated as an unsupervised vector quantization process, where the local values...

评估了一种基于模糊学习矢量量化（FALVQ）算法的脑部磁共振（MR）图像分割技术。这些算法通过无监督学习过程更新竞争网络的所有原型来执行矢量量化。MR图像分割被表述为一个无监督的矢量量化过程，其中局部值...

This paper addresses one of the major problems in interventional magnetic resonance imaging (MRI): the visualization of interventional devices. For visualization locally induced magnetic fields are used, which disturb the homogeneity of the main magnetic field of the MR scanner. This results in signal loss in the vicinity of the device due to intravoxel dephasing, and leads to a disturbance of the...

本文讨论了介入性磁共振成像（MRI）中的一个主要问题：介入设备的可视化。可视化利用局部感应磁场，该磁场会干扰MR扫描器主磁场的均匀性。这导致由于体素内去相位而在设备附近出现信号丢失，并引起……

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...

We describe a fast and globally convergent fully four-dimensional incremental gradient (4DIG) algorithm to estimate the continuous-time tracer density from list mode positron emission tomography (PET) data. Detection of 511-keV photon pairs produced by positron-electron annihilation is modeled as an inhomogeneous Poisson process whose rate function is parameterized using cubic $B$-splines. The ra...

我们描述了一种快速且全局收敛的全四维增量梯度（4DIG）算法，用于从列表模式正电子发射断层扫描（PET）数据中估计连续时间示踪剂密度。将正电子-电子湮灭产生的511 keV光子对检测建模为非齐次泊松过程，其速率函数使用三次B样条参数化。

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...

A highly automated method for the identification and quantization of maximum blood velocity curves from Doppler ultrasound flow diagrams is presented. The method uses an image processing scheme to analyze video-recorded image sequences of flow diagrams. The sequences are acquired, a sequence of images relating to chronological cardiac cycles is extracted, and a maximum blood velocity envelope is d...

提出了一种高度自动化的方法，用于从多普勒超声血流图中识别和量化最大血流速度曲线。该方法采用图像处理方案分析视频记录的流图图像序列。获取序列后，提取与时间心搏周期相关的图像序列，并确定最大血流速度包络...

An upper bound is derived for the mutual information between a fixed image and a deformable template containing a fixed number of gray-levels. The bound can be calculated by maximizing the entropy of the template under the constraint that the conditional entropy of the template, given the fixed image, be zero. This bound provides useful insight into the properties of mutual information as a simila...

推导了固定图像与包含固定灰度级数的可变形模板之间互信息的上界。该界可以通过在给定固定图像条件下模板的条件熵为零的约束下最大化模板的熵来计算。该界为互信息作为相似度量的性质提供了有用的见解...

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……

The use of selective internal radiation therapy for treatment of hepatocellular carcinoma and liver metastases using Y-90 labeled microspheres has become an effective and widely used treatment regimen. However, dosimetric evaluations of this treatment are still primitive as uniform distribution models based only on injected activity are often used. This investigation attempts to quantify the effec...

使用Y-90标记微球的选择性内放射疗法治疗肝细胞癌和肝转移瘤已成为一种有效且广泛应用的治疗方案。然而，该治疗的剂量学评估仍然较为原始，因为通常仅基于注射活度的均匀分布模型。本研究试图量化...

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……

High-resolution single-photon emission computed tomography (SPECT) imaging in small animals tends to use long imaging times and large injected doses due to the poor sensitivity of single pinhole gamma cameras. To increase sensitivity while maintaining spatial resolution, we designed and constructed a multi-pinhole collimator array to replace the parallel hole collimators of a Ceraspect human SPECT...

由于单针孔伽马相机的灵敏度较低，小动物高分辨率单光子发射计算机断层扫描（SPECT）成像往往需要较长的成像时间和较大的注射剂量。为了在保持空间分辨率的同时提高灵敏度，我们设计并构建了一个多针孔准直器阵列，以替代Ceraspect人体SPECT的平行孔准直器...

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

A new postprocessing algorithm was developed for the diagnosis of breast cancer using electrical impedance scanning. This algorithm automatically recognizes bright focal spots in the conductivity map of the breast. Moreover, this algorithm discriminates between malignant and benign/normal tissues using two main predictors: phase at 5 kHz and crossover frequency, the frequency at which the imaginar...

开发了一种新的后处理算法，用于使用电阻抗扫描进行乳腺癌诊断。该算法自动识别乳房电导率图中的明亮焦点斑。此外，该算法使用两个主要预测因子区分恶性组织和良性/正常组织：5 kHz时的相位和交叉频率，即虚部消失的频率...

In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpne...

在眼底摄影中，精细对焦是一项要求高且常常因对焦不准导致图像质量不佳的任务。数码相机的引入为实现自动对焦提供了机会。我们开发了一种能够识别最佳对焦的软件算法。自动对焦方法基于我们开发的评估图像锐度的算法……

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

A dye-edge tracking algorithm was used to determine the corresponding points in the two images (anterior-posterior and lateral) of the digital subtraction biplane angiography. This correspondence was used to reconstruct three-dimensional images of cerebral arteries in a dog experiment and a clinical observation. The method was tested by comparing the measured image of oblique view to the computed ...

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...

The determination of the sources of electric activity inside the brain from electric and magnetic measurements on the surface of the head is known to be an ill-posed problem. In this paper, a new algorithm which takes temporal a priori information modeled by the smooth activation model into account is described and compared with existing algorithms such as Tikhonov-Phillips.

从头部表面的电学和磁学测量确定脑内电活动的源是一个已知的不适定问题。本文描述了一种考虑由平滑激活模型建模的时间先验信息的新算法，并与Tikhonov-Phillips等现有算法进行了比较。

For noisy X-ray fluoroscopy image sequences the authors quantitatively evaluated image quality after digital temporal filtering to reduce noise. Using an experimental paradigm called a reference/test adaptive forced-choice method the authors compared detectability of stationary low-contrast disks in filtered and un-filtered, computer-generated image sequences. In the first experiment, a low-pass f...

对于噪声较大的X射线透视图像序列，作者通过数字时间滤波来降低噪声，并对其图像质量进行了定量评估。采用一种称为参考/测试自适应强制选择方法的实验范式，作者比较了滤波和未滤波计算机生成图像序列中静止低对比度圆盘的可见性。在第一个实验中，低通滤波...

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。