Volume 20, Issue 8

A novel speckle suppression method for medical ultrasound images is presented. First, the logarithmic transform of the original image is analyzed into the multiscale wavelet domain. The authors show that the subband decompositions of ultrasound images have significantly non-Gaussian statistics that are best described by families of heavy-tailed distributions such as the alpha-stable. Then, the authors design a Bayesian estimator that exploits these statistics. They use the alpha-stable model to develop a blind noise-removal processor that performs a nonlinear operation on the data. Finally, the authors compare their technique with current state-of-the-art soft and hard thresholding methods applied on actual ultrasound medical images and they quantify the achieved performance improvement.

提出了一种用于医学超声图像斑点抑制的新方法。首先，将原始图像的对数变换分析到多尺度小波域。作者表明，超声图像的子带分解具有显著的非高斯统计特性，这些特性最好由诸如α稳定分布等重尾分布族来描述。然后，作者设计了一个利用这些统计特性的贝叶斯估计器。他们使用α稳定模型开发了一个盲噪声去除处理器，对数据执行非线性操作。最后，作者将他们的技术与当前最先进的软阈值和硬阈值方法应用于实际超声医学图像上，并量化了所实现的性能改进。

This paper presents a fully automated algorithm for segmentation of multiple sclerosis (MS) lesions from multispectral magnetic resonance (MR) images. The method performs intensity-based tissue classification using a stochastic model for normal brain images and simultaneously detects MS lesions as outliers that are not well explained by the model. It corrects for MR field inhomogeneities, estimate...

本文提出一种全自动算法，用于从多光谱磁共振（MR）图像中分割多发性硬化（MS）病灶。该方法利用正常脑图像的随机模型进行基于强度的组织分类，同时将模型中无法很好解释的异常点检测为MS病灶。它校正了MR场不均匀性，并估计...

Clinical assessment of skeletal maturity is based on a visual comparison of a left-hand wrist radiograph with atlas patterns. Using a new digital hand atlas an image analysis methodology is being developed. To assist radiologists in bone age estimation. The analysis starts with a preprocessing function yielding epiphyseal/metaphyseal regions of interest (EMROIs). Then, these regions are subjected ...

临床骨骼成熟度评估基于左手腕X光片与图谱模式的视觉比较。利用新的数字手部图谱，正在开发一种图像分析方法，以辅助放射科医生进行骨龄评估。分析始于预处理功能，生成骨骺/干骺端感兴趣区域（EMROI）。随后，这些区域接受进一步处理......

Pinhole collimators are widely used to image small organs and animals. The sensitivity of knife-edge pinhole collimators has been previously estimated using an "effective diameter" formulation and experimentally described using a sin/sup /spl infin// /spl theta/ fit, where /spl theta/ is the angle between the line segment from the center of the aperture to the photon source and its projection onto...

针孔准直器广泛用于小器官和动物成像。先前已使用“有效直径”公式估计刀刃针孔准直器的灵敏度，并通过sin/sup /spl infin// /spl theta/拟合进行实验描述，其中/spl theta/是从孔径中心到光子源并投影到...

Data security becomes more and more important in telemammography which uses a public high-speed wide area network connecting the examination site with the mammography expert center. Generally, security is characterized in terms of privacy, authenticity and integrity of digital data. Privacy is a network access issue and is not considered in this paper. The authors present a method, authenticity an...

在远程乳腺X线摄影中，使用公共高速广域网连接检查地点和乳腺X线专家中心，数据安全性变得越来越重要。通常，安全性体现在数字数据的隐私性、可靠性和完整性方面。隐私是一个网络访问问题，本文不予考虑。作者提出了一种方法，可靠性和...

The combination of Fourier rebinning (FORE) and the ordered subsets expectation-maximization (OSEM), a fast statistical algorithm, appears as a promising alternative to the fully three-dimensional (3-D) iterative approach for clinical positron emission tomography (PET) data. Here, the authors evaluated the properties of FORE+OSEM and compared it with fully 3-D OSEM using both simulations and data ...

傅里叶重分箱(FORE)与有序子集期望最大化(OSEM)（一种快速统计算法）的组合，似乎是临床正电子发射断层扫描(PET)数据中全三维(3-D)迭代方法的有前途的替代方案。本文作者评估了FORE+OSEM的特性，并通过模拟和数据将其与全三维OSEM进行了比较...

Ultrasound beams propagating in biological tissues undergo distortions due to local inhomogeneities of the acoustic parameters and the nonlinearity of the medium. The spectral analysis of the radio-frequency (RF) backscattered signals may yield important clinical information in the field of tissue characterization, as well as enhancing the detectability of tissue parenchymal diseases. Here, the au...

超声束在生物组织中传播时会因声学参数的局部不均匀性和介质的非线性而发生畸变。对射频（RF）背向散射信号进行频谱分析，可以在组织表征领域获得重要的临床信息，并提高实质组织疾病的检测能力。本文...

Studies reported in the literature indicate that breast cancer risk is associated with mammographic densities. An objective, repeatable, and a quantitative measure of risk derived from mammographic densities will be of considerable use in recommending alternative screening paradigms and/or preventive measures. However, image processing efforts toward this goal seem to be sparse in the literature, ...

据文献报道，乳腺X线密度与乳腺癌风险相关。基于乳腺X线密度得出的客观、可重复且定量的风险测量指标，对于推荐替代筛查方案和/或预防措施具有重要价值。

Presents a near-automatic process for separating vessels from background and other clutter as well as for separating arteries and veins in contrast-enhanced magnetic resonance angiographic (CE-MRA) image data, and an optimal method for three-dimensional visualization of vascular structures. The separation process utilizes fuzzy connected object delineation principles and algorithms. The first step...

提出了一种接近自动化的过程，用于从对比增强磁共振血管造影（CE-MRA）图像数据中分离血管与背景及其他杂波，以及分离动脉和静脉，并提出了血管结构三维可视化的优化方法。该分离过程利用了模糊连接目标描绘原理和算法。第一步...

The low signal-to-noise ratio (SNR) in emission data has stimulated the development of statistical image reconstruction methods based on the maximum a posteriori (MAP) principle. Experimental examples have shown that statistical methods improve image quality compared to the conventional filtered backprojection (FBP) method. However, these results depend on isolated data sets. Here, the authors stu...

发射数据中的低信噪比（SNR）促进了基于最大后验（MAP）原理的统计图像重建方法的发展。实验实例表明，与传统的滤波反投影（FBP）方法相比，统计方法提高了图像质量。然而，这些结果依赖于孤立的数据集。这里，作者研究了...

A framework for modeling and predicting anatomical deformations is presented, and tested on simulated images. Although a variety of deformations can be modeled in this framework, emphasis is placed on surgical planning, and particularly on modeling and predicting changes of anatomy between preoperative and intraoperative positions, as well as on deformations induced by tumor growth. Two methods ar...

本文提出了一种用于建模和预测解剖变形的框架，并在模拟图像上进行了测试。尽管该框架可以建模多种变形，但重点放在手术规划上，特别是术前和术中位置之间解剖变化的建模和预测，以及肿瘤生长引起的变形。两种方法...

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...

Functional magnetic resonance (MR) MR imaging (fMRI) with blood-oxygenation-level-dependent (BOLD) contrast localizes neuronal processing of cognitive paradigms. As magnetic resonance signal responses are small, functional mapping requires statistical analysis of temporally averaged image data. Although voxels activating at the paradigm frequency can be identified from the Fourier power spectrum, ...

功能磁共振成像（fMRI）利用血氧水平依赖（BOLD）对比定位认知任务的神经处理。由于磁共振信号响应较弱，功能映射需要对时间平均图像数据进行统计分析。虽然可以从傅里叶功率谱中识别出以范式频率激活的体素，...

An aneurysm of the abdominal aorta (AAA) is characterized by modified wall properties, and a balloon-like area usually filled by a thrombus. A rupture of an aortic aneurysm can be fatal, yet there is no way to accurately predict such an occurrence. The study of the wall and thrombus cross-sectional distension, due to a pressure wave, is important as a way of assessing the degradation of the mechan...

腹主动脉瘤的特征是血管壁特性改变，形成气球样区域，通常充满血栓。主动脉瘤破裂可能是致命的，但目前尚无准确预测的方法。由于压力波引起的血管壁和血栓横截面扩张的研究，作为评估机械性能退化的一种手段非常重要...

High-resolution three-dimensional (3-D) volumetric images obtained by today's radiologic imaging scanners are rich in detailed diagnostic information. Despite the many visualization techniques available to assess such images, there remains information that is challenging to uncover, such as the location of small structures (e.g., mediastinal lymph nodes, narrowed-airway regions). Recently, sliding...

当今放射影像扫描仪获取的高分辨率三维体积图像富含详细的诊断信息。尽管有多种可视化技术可用于评估此类图像，但仍有一些信息难以揭示，例如小结构的位置（如纵隔淋巴结、狭窄气道区域）。最近，滑动...

Using a one-dimensional convective-dispersive model of contrast agent flow in a blood vessel, the authors optimized and compared algorithms for combining a temporal sequence of X-ray angiography images, each with incomplete arterial filling, into a single-output image with fully opacified arteries. The four algorithms were: maximum opacity (MO) with a maximum over time at each spatial location; ma...

利用一维对流-弥散模型描述血管中造影剂的流动，作者优化并比较了将一系列时间序列的X射线血管造影图像（每张图像中动脉填充不完全）融合为单一输出图像（动脉完全显影）的算法。四种算法是：最大不透明度（MO），在每个空间位置取时间上的最大值；...