Volume 16, Issue 6

Describes a fully-automatic three-dimensional (3-D)-segmentation technique for brain magnetic resonance (MR) images. By means of Markov random fields (MRF's) the segmentation algorithm captures three features that are of special importance for MR images, i.e., nonparametric distributions of tissue intensities, neighborhood correlations, and signal inhomogeneities. Detailed simulations and real MR images demonstrate the performance of the segmentation algorithm. In particular, the impact of noise, inhomogeneity, smoothing, and structure thickness are analyzed quantitatively. Even single-echo MR images are well classified into gray matter, white matter, cerebrospinal fluid, scalp-bone, and background. A simulated annealing and an iterated conditional modes implementation are presented.

描述了一种用于脑部磁共振（MR）图像的全自动三维（3-D）分割技术。通过马尔可夫随机场（MRF），该分割算法捕捉了MR图像中特别重要的三个特征，即组织强度的非参数分布、邻域相关性和信号不均匀性。详细的模拟和真实MR图像展示了分割算法的性能。特别地，定量分析了噪声、不均匀性、平滑和结构厚度的影响。即使是单回波MR图像也能很好地分类为灰质、白质、脑脊液、头皮骨骼和背景。文中介绍了模拟退火和迭代条件模式两种实现方法。

Presents diffeomorphic transformations of three-dimensional (3-D) anatomical image data of the macaque occipital lobe and whole brain cryosection imagery and of deep brain structures in human brains as imaged via magnetic resonance imagery. These transformations are generated in a hierarchical manner, accommodating both global and local anatomical detail. The initial low-dimensional registration i...

介绍了猕猴枕叶和全脑冷冻切片图像以及通过磁共振成像的人类大脑深层脑结构的三维（3-D）解剖图像数据的微分同胚变换。这些变换以层次方式生成，兼顾全局和局部解剖细节。初始的低维配准...

Presents the use of an entropy focus criterion to enable automatic focusing of motion corrupted magnetic resonance images. The authors demonstrate the principle using illustrative examples from cooperative volunteers. Their technique can determine unknown patient motion or use knowledge of motion from other measures as a starting estimate. The motion estimate is used to compensate the acquired dat...

介绍了使用熵聚焦准则来自动聚焦运动污染的磁共振图像。作者通过合作志愿者的示例说明了该原理。他们的技术可以确定未知的患者运动，或利用来自其他测量的运动知识作为初始估计。运动估计用于补偿采集的数据...

Most benign breast tumors possess well-defined, sharp boundaries that delineate them from surrounding tissues, as opposed to malignant tumors. Computer techniques proposed to date for tumor analysis have concentrated on shape factors of tumor regions and texture measures. While shape measures based on contours of tumor regions can indicate differences in shape complexities between circumscribed an...

大多数良性乳腺肿瘤具有清晰、锐利的边界，将它们与周围组织区分开来，而恶性肿瘤则不然。迄今提出的用于肿瘤分析的计算机技术主要集中在肿瘤区域的形状因子和纹理度量上。虽然基于肿瘤区域轮廓的形状度量可以指示边界清晰的肿瘤与...之间的形状复杂性差异。

Describes a system that is being used to segment gray matter from magnetic resonance imaging (MRI) and to create connected cortical representations for functional MRI visualization (fMRI). The method exploits knowledge of the anatomy of the cortex and incorporates structural constraints into the segmentation. First, the white matter and cerebral spinal fluid (CSF) regions in the MR volume are segm...

描述了一种系统，该系统用于从磁共振成像（MRI）中分割灰质，并创建用于功能磁共振成像可视化（fMRI）的连通皮层表示。该方法利用了皮层解剖学知识，并在分割中加入了结构约束。首先，在MR体积中分割白质和脑脊液（CSF）区域...

Presents a fully automated process for segmentation and classification of multispectral magnetic resonance (MR) images. This hybrid neural network method uses a Kohonen self-organizing neural network for segmentation and a multilayer backpropagation neural network for classification. To separate different tissue types, this process uses the standard T1-, T2-, and PD-weighted MR images acquired in ...

提出了一种完全自动化的多光谱磁共振图像分割和分类方法。该混合神经网络方法使用Kohonen自组织神经网络进行分割，并使用多层反向传播神经网络进行分类。为了分离不同的组织类型，该方法使用了标准T1、T2和PD加权MR图像采集的...

Presents an automated, knowledge-based method for segmenting chest computed tomography (CT) datasets. Anatomical knowledge including expected volume, shape, relative position, and X-ray attenuation of organs provides feature constraints that guide the segmentation process. Knowledge is represented at a high level using an explicit anatomical model. The model is stored in a frame-based semantic net...

介绍了一种自动化的、基于知识的方法，用于分割胸部计算机断层扫描（CT）数据集。包括器官的预期体积、形状、相对位置和X射线衰减在内的解剖知识提供了指导分割过程的特征约束。知识使用显式解剖模型在高层次上表示。该模型存储在基于框架的语义网络中...

Airway geometry measurements can provide information regarding pulmonary physiology and pathophysiology. There has been considerable interest in measuring intrathoracic airways in two-dimensional (2-D) slices from volumetric X-ray computed tomography (CT). Such measurements can be used to evaluate and track the progression of diseases affecting the airways. A popular airway measurement method uses...

气道几何测量可以提供关于肺生理和病理生理的信息。人们对从体积X射线计算机断层扫描（CT）的二维切片中测量胸内气道产生了相当大的兴趣。这些测量可用于评估和跟踪影响气道疾病的进展。一种流行的气道测量方法使用...

The objective of this research is to model the mammographic parenchymal and ductal patterns and enhance the microcalcifications using a deterministic fractal approach. According to the theory of deterministic fractal geometry, images can be modeled by deterministic fractal objects which are attractors of sets of two-dimensional (2-D) affine transformations. The iterated functions systems and the c...

本研究的目的是使用确定性分形方法对乳腺实质和导管模式进行建模，并增强微钙化。根据确定性分形几何理论，图像可以通过确定性分形对象建模，这些对象是二维仿射变换集合的吸引子。迭代函数系统和...

A new model-based vision (MBV) algorithm is developed to find regions of interest (ROI's) corresponding to masses in digitized mammograms and to classify the masses as malignant/benign. The MBV algorithm is comprised of 5 modules to structurally identify suspicious ROI's, eliminate false positives, and classify the remaining as malignant or benign. The focus of attention module uses a difference of Gaussians (DoG) filter to highlight suspicious regions in the mammogram. The index module uses tests to reduce the number of nonmalignant regions from 8.39 to 2.36 per full breast image. Size, shape, contrast, and Laws texture features are used to develop the prediction module's mass models. Derivative-based feature saliency techniques are used to determine the best features for classification. Nine features are chosen to define the malignant/benign models. The feature extraction module obtains these features from all suspicious ROI's. The matching module classifies the regions using a multilayer perceptron neural network architecture to obtain an overall classification accuracy of 100% for the segmented malignant masses with a false-positive rate of 1.8 per full breast image. This system has a sensitivity of 92% for locating malignant ROI's. The database contains 272 images (12 b, 100 /spl mu/m) with 36 malignant and 53 benign mass images. The results demonstrate that the MBV approach provides a structured order of integrating complex stages into a system for radiologists.

提出了一种新的基于模型的视觉（MBV）算法，用于在数字化乳腺X光片中识别与肿块对应的感兴趣区域（ROI），并将肿块分类为恶性/良性。该MBV算法由5个模块组成，用于结构性地识别可疑ROI、消除假阳性，并将剩余的分类为恶性或良性。注意力聚焦模块使用高斯差...

This article presents a detailed description of an algorithm for the automatic detection of the mid-sagittal plane in three-dimensional (3-D) brain images. The algorithm seeks the plane with respect to which the image exhibits maximum symmetry. For a given plane, symmetry is measured by the cross-correlation between the image sections lying on either side. The search for the plane of maximum symme...

本文详细介绍了一种用于三维脑图像中矢状面自动检测的算法。该算法寻找使图像表现出最大对称性的平面。对于给定平面，对称性通过两侧图像区域之间的互相关来测量。寻找最大对称性平面的搜索...

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 article presents a new method for analyzing the spreading of skin erythemas. These occur as a result of the cutaneous vascular axon reflex which can be evoked by a noxious stimulation of the skin. Series of true-color images of the observed skin patch were recorded using a video camera. The images were digitized and stored on computer disk. The delineation of the reddening was segmented for e...

本文介绍了一种分析皮肤红斑扩散的新方法。这些红斑是由于皮肤血管轴突反射引起的，可通过皮肤的有害刺激诱发。使用摄像机记录观察到的皮肤斑块的一系列真彩色图像。图像被数字化并存储在计算机磁盘上。红斑的轮廓被分割以进行...

The use of anatomical information to improve the quality of reconstructed images in positron emission tomography (PET) has been extensively studied. A common strategy has been to include spatial smoothing within boundaries defined from the anatomical data. The authors present an alternative method for the incorporation of anatomical information into PET image reconstruction, in which they use segm...

利用解剖信息改善正电子发射断层扫描（PET）重建图像质量的方法已被广泛研究。一种常见策略是在由解剖数据定义的边界内进行空间平滑。作者提出了一种将解剖信息纳入PET图像重建的替代方法，其中他们使用分割...

Phase contrast magnetic resonance imaging (MRI) can provide in vivo myocardial velocity field measurements. These data allow densely spaced material points to be tracked throughout the whole heart cycle using, for example, the Fourier tracking algorithm. To process the tracking results for myocardial deformation and strain quantification, the authors developed a method that is based on fitting the...

相位对比磁共振成像（MRI）可以提供体内心肌速度场测量。这些数据允许使用例如傅里叶跟踪算法在整个心动周期中追踪密集分布的物质点。为了处理追踪结果以量化心肌变形和应变，作者开发了一种基于拟合...的方法。

Many image-reconstruction methods have been proposed to improve the spatial resolution of positron emission tomography (PET) images and, thus, to produce better quantification. However, these techniques, which are designed for static images, may be inadequate for good reconstruction from dynamic data. The authors present a simple, but effective, reconstruction approach intended specifically for dy...

已提出许多图像重建方法来提高正电子发射断层扫描（PET）图像的空间分辨率，从而产生更好的量化结果。然而，这些专为静态图像设计的技术可能不足以从动态数据中实现良好的重建。作者提出了一种简单而有效的重建方法，专门用于动态...

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。

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...

Fractal dimension (FD) is a feature which is widely used to characterize medical images. Previously, researchers have shown that FD separates important classes of images and provides distinctive information about texture. The authors analyze limitations of two principal methods of estimating FD: box-counting (BC) and power spectrum (PS). BC is ineffective when applied to data-limited, low-resoluti...

分形维数是一种广泛用于表征医学图像的特征。先前的研究表明，分形维数能够区分重要的图像类别并提供关于纹理的独特信息。作者分析了两种主要分形维数估计方法的局限性：盒计数法和功率谱法。盒计数法在数据有限、低分辨率的情况下无效……

A novel method to automatically recognize and remove background signals in computed radiography (CR) images caused by X-ray collimation during projection radiographic examinations is presented. There are three major steps in this method. In the first step, a statistical curve is derived based on many hierarchical CR sample images as a first approximation to loosely separate image and background pi...

提出了一种新方法，用于自动识别并去除在投影X射线检查中由X射线准直引起的计算机放射（CR）图像中的背景信号。该方法包括三个主要步骤。第一步，基于多个分层CR样本图像推导出一条统计曲线，作为粗略分离图像和背景的初步近似...

A number of segmentation algorithms have been developed, but those algorithms are not effective on volume reconstruction because they are limited to operating only on two-dimensional (2-D) images. Here, the authors propose the volumetric object reconstruction method using the three-dimensional Markov random field (3D-MRF) model-based segmentation. The 3D-MRF model is known to be one of the most ef...

已经开发了许多分割算法，但这些算法对体积重建效果不佳，因为它们仅限于在二维（2-D）图像上操作。在此，作者提出了使用基于三维马尔可夫随机场（3D-MRF）模型分割的体积目标重建方法。3D-MRF模型被认为是最高效...

Four scatter-compensation schemes are considered. The 4 schemes are all based on a previously developed two-dimensional (2-D) scatter model. Reconstruction is achieved using the iterative expectation-maximization maximum-likelihood (EM-ML) algorithm. The schemes consist of: (1) including the model in both the forward and back projector; (2) just including the model in the forward projector; (3) an...

考虑了四种散射补偿方案。这四种方案均基于先前开发的二维（2-D）散射模型。使用迭代期望最大化最大似然（EM-ML）算法实现重建。这些方案包括：（1）在前向和反向投影仪中都包含模型；（2）仅在前向投影仪中包含模型；（3）……

Reconstructing vasculature in three dimensions is a challenging problem. Early approaches concentrated on coronary vasculature in X-ray images, recent work uses magnetic resonance imagery of cerebral vasculature. In both cases a priori information has been used, and often the way this is represented has proven limiting to the scope of applications supported. For example, a particular representatio...

三维重建血管网络是一个具有挑战性的问题。早期方法集中在X射线图像中的冠状动脉血管，最近的工作使用脑部血管的磁共振成像。在这两种情况下，都使用了先验信息，而通常这种表示方式限制了所支持的应用范围。例如，一种特定的表示...

Digitizing high-quality microscopic images and developing input/output technology for displaying those results is critical to telepathology in which pathological microscopic images are transferred to remote locations where they are diagnosed by specialists. Here, the authors discuss the results achieved by directly digitizing (nonfilm process) pathological microscopic images at a 2 k/spl times/2 k...

将高质量显微图像数字化并开发用于显示这些结果的输入/输出技术对远程病理学至关重要，远程病理学将病理显微图像传输到远程位置，由专家进行诊断。在此，作者讨论了通过直接数字化（非胶片工艺）2k×2k...病理显微图像所获得的结果。

Simple chest X-rays on film are the most common type of image in medical diagnosis. However, amongst the various types of medical X-ray images, they require the highest level of display quality due to the fact that the body structures they capture on film have varying degrees of permeability to X-rays. Conventional high-definition digital display technology has not always been able to match the qu...

简单胸部X光胶片是医学诊断中最常见的图像类型。然而，在各种类型的医学X射线图像中，它们对显示质量的要求最高，因为它们在胶片上捕捉到的身体结构对X射线的渗透程度不同。传统的高清数字显示技术并不总能匹配其质量要求...