Volume 22, Issue 9

The clinical recognition of abnormal vascular tortuosity, or excessive bending, twisting, and winding, is important to the diagnosis of many diseases. Automated detection and quantitation of abnormal vascular tortuosity from three-dimensional (3-D) medical image data would, therefore, be of value. However, previous research has centered primarily upon two-dimensional (2-D) analysis of the special subset of vessels whose paths are normally close to straight. This report provides the first 3-D tortuosity analysis of clusters of vessels within the normally tortuous intracerebral circulation. We define three different clinical patterns of abnormal tortuosity. We extend into 3-D two tortuosity metrics previously reported as useful in analyzing 2-D images and describe a new metric that incorporates counts of minima of total curvature. We extract vessels from MRA data, map corresponding anatomical regions between sets of normal patients and patients with known pathology, and evaluate the three tortuosity metrics for ability to detect each type of abnormality within the region of interest. We conclude that the new tortuosity metric appears to be the most effective in detecting several types of abnormalities. However, one of the other metrics, based on a sum of curvature magnitudes, may be more effective in recognizing tightly coiled, "corkscrew" vessels associated with malignant tumors.

临床上识别异常血管迂曲度，即过度弯曲、扭转和缠绕，对于许多疾病的诊断非常重要。因此，从三维（3-D）医学图像数据中自动检测和量化异常血管迂曲度将具有重要价值。然而，先前的研究主要集中在二维（2-D）分析那些路径通常接近直线的特殊血管子集上。本报告首次对正常迂曲的脑内循环中的血管簇进行了三维迂曲度分析。我们定义了三种不同的异常迂曲度临床模式。我们将先前报道的在分析二维图像时有用的两个迂曲度指标扩展到三维，并描述了一个新指标，该指标包含了总曲率极小值的计数。我们从MRA数据中提取血管，在正常患者和已知病理患者组之间映射相应的解剖区域，并评估这三个迂曲度指标在感兴趣区域内检测每种异常类型的能力。我们得出结论，新的迂曲度指标在检测多种异常类型方面似乎最为有效。然而，基于曲率幅度之和的另一个指标可能在识别与恶性肿瘤相关的紧密盘绕的“开瓶器”状血管方面更为有效。

An adaptive spatial fuzzy c-means clustering algorithm is presented in this paper for the segmentation of three-dimensional (3-D) magnetic resonance (MR) images. The input images may be corrupted by noise and intensity nonuniformity (INU) artifact. The proposed algorithm takes into account the spatial continuity constraints by using a dissimilarity index that allows spatial interactions between im...

本文提出了一种用于三维磁共振图像分割的自适应空间模糊c均值聚类算法。输入图像可能受到噪声和强度不均匀性（INU）伪影的影响。该算法通过使用一个允许空间相互作用的相异性指数来考虑空间连续性约束...

Edge-preserving denoising is of great interest in medical image processing. This paper presents a wavelet-based multiscale products thresholding scheme for noise suppression of magnetic resonance images. A Canny edge detector-like dyadic wavelet transform is employed. This results in the significant features in images evolving with high magnitude across wavelet scales, while noise decays rapidly. ...

边缘保持去噪在医学图像处理中具有重要研究价值。本文提出一种基于小波的多尺度乘积阈值化方案用于磁共振图像的噪声抑制。采用类似Canny边缘检测器的二进小波变换。这使得图像中的显著特征在小波尺度上以高幅度演化，而噪声迅速衰减。

Although numerous methods to register brains of different individuals have been proposed, no work has been done, as far as we know, to evaluate and objectively compare the performances of different nonrigid (or elastic) registration methods on the same database of subjects. In this paper, we propose an evaluation framework, based on global and local measures of the relevance of the registration. W...

尽管已经提出了许多配准不同个体大脑的方法，但据我们所知，还没有工作在相同受试者数据库上评估和客观比较不同非刚性（或弹性）配准方法的性能。在本文中，我们提出了一个基于全局和局部配准相关性度量的评估框架。

Mutual information (MI)-based image registration has been found to be quite effective in many medical imaging applications. To determine the MI between two images, the joint histogram of the two images is required. In the literature, linear interpolation and partial volume interpolation (PVI) are often used while estimating the joint histogram for registration purposes. It has been shown that join...

基于互信息（MI）的图像配准在许多医学成像应用中已被证明非常有效。为了确定两幅图像之间的互信息，需要两幅图像的联合直方图。文献中，线性插值和部分体积插值（PVI）常用于估计用于配准的联合直方图。已有研究表明，联合...

Regularization is desirable for image reconstruction in emission tomography. A powerful regularization method is the penalized-likelihood (PL) reconstruction algorithm (or equivalently, maximum a posteriori reconstruction), where the sum of the likelihood and a noise suppressing penalty term (or Bayesian prior) is optimized. Usually, this approach yields position-dependent resolution and bias. How...

在发射断层成像中，图像重建需要正则化。一种强大的正则化方法是惩罚似然（PL）重建算法（或等效的最大后验重建），其中优化了似然函数与噪声抑制惩罚项（或贝叶斯先验）之和。通常，这种方法会导致位置相关的分辨率和偏差。如何...

Manual selection of single particles in images acquired using cryo-electron microscopy (cryoEM) will become a significant bottleneck when a very large number of images are required to achieve three-dimensional reconstructions at near atomic resolution. Investigation of fast, accurate approaches for automatic particle detection has become one of the current challenges in the cryoEM community. At th...

在采用低温电子显微镜（cryoEM）获取的图像中手动选择单个粒子，当需要大量图像以实现近原子分辨率的三维重建时，将成为重大瓶颈。研究快速、准确的自动粒子检测方法已成为当前cryoEM领域的挑战之一。

A neural-network-based framework has been developed to search for an optimal wavelet kernel that can be used for a specific image processing task. In this paper, a linear convolution neural network was employed to seek a wavelet that minimizes errors and maximizes compression efficiency for an image or a defined image pattern such as microcalcifications in mammograms and bone in computed tomograph...

已经开发了一个基于神经网络的框架，用于搜索可用于特定图像处理任务的最优小波核。本文采用线性卷积神经网络来寻找一种小波，该小波能够最小化误差并最大化图像或定义的图像模式（例如乳腺X线摄影中的微钙化和计算机断层扫描中的骨骼）的压缩效率。

System design and initial phantom accuracy results for a novel biopsy system integrating both magnetic resonance (MR) and ultrasound (US) imaging modalities are presented. A phantom experiment was performed to investigate the efficacy of this hybrid guidance biopsy technique in a breast tissue mimicking phantom. A comparison between MR-guided core biopsy verses MR/US-guided core biopsy of phantom ...

介绍了一种新型活检系统的系统设计和初始体模精度结果，该系统整合了磁共振（MR）和超声（US）成像模态。在乳腺组织模拟体模中进行了一项体模实验，以研究这种混合引导活检技术的有效性。比较了MR引导下核心活检与MR/US引导下核心活检在体模中的表现……

Measuring the thickness of sheet-like thin anatomical structures, such as articular cartilage and brain cortex, in three-dimensional (3-D) magnetic resonance (MR) images is an important diagnostic procedure. This paper investigates the fundamental limits on the accuracy of thickness determination in MR images. We defined thickness here as the distance between the two sides of boundaries measured a...

测量三维磁共振图像中薄片状解剖结构（如关节软骨和大脑皮层）的厚度是一项重要的诊断程序。本文研究了磁共振图像中厚度确定精度的基本极限。我们将厚度定义为测量所得边界两侧之间的距离...

This paper presents an analysis of the mutual information (MI) metric in rigid-body registration of two digital images, in particular, local fluctuations of the MI value due to interpolation. In contrast to existing work in this area, this paper starts with two hypothetical continuous images, based on which both sampling and interpolation effects are analyzed. This analysis indicates that an "idea...

本文分析了两个数字图像刚体配准中的互信息度量，特别是由于插值引起的互信息值的局部波动。与现有工作不同，本文从两个假设的连续图像开始，分析采样和插值效应。分析表明，一个“想法”...

This paper presents a new framework for capturing intrinsic visual search behavior of different observers in image understanding by analysing saccadic eye movements in feature space. The method is based on the information theory for identifying salient image features based on which visual search is performed. We demonstrate how to obtain feature space fixation density functions that are normalized...

本文提出了一种新框架，通过分析特征空间中的眼跳运动来捕捉不同观察者在图像理解中的内在视觉搜索行为。该方法基于信息论，用于识别显著图像特征，并据此进行视觉搜索。我们演示了如何获得特征空间注视密度函数，这些函数是归一化的...

The aim of this study was to assess polyethylene wear in a total hip prosthesis by digitized radiography of the whole pelvis in the anteroposterior (AP) plane. The three-dimensional (3-D) pose of the nonmetal-backed acetubular cup, materialized by its metal ring and the femoral head made of metal or ceramic, was estimated using iterative algebraic algorithms with inner bias correction and bootstra...

本研究旨在通过数字化前后位（AP）平面骨盆X线摄影评估全髋假体中的聚乙烯磨损。使用带有内部偏差校正和自举法的迭代代数算法，估计由金属环和金属或陶瓷股骨头实现的非金属支撑髋臼杯的三维（3-D）姿态。