Volume 21, Issue 3

We present a novel algorithm for fuzzy segmentation of magnetic resonance imaging (MRI) data and estimation of intensity inhomogeneities using fuzzy logic. MRI intensity inhomogeneities can be attributed to imperfections in the radio-frequency coils or to problems associated with the acquisition sequences. The result is a slowly varying shading artifact over the image that can produce errors with conventional intensity-based classification. Our algorithm is formulated by modifying the objective function of the standard fuzzy c-means (FCM) algorithm to compensate for such inhomogeneities and to allow the labeling of a pixel (voxel) to be influenced by the labels in its immediate neighborhood. The neighborhood effect acts as a regularizer and biases the solution toward piecewise-homogeneous labelings. Such a regularization is useful in segmenting scans corrupted by salt and pepper noise. Experimental results on both synthetic images and MR data are given to demonstrate the effectiveness and efficiency of the proposed algorithm.

我们提出了一种新颖的模糊分割算法，用于磁共振成像（MRI）数据的模糊分割和强度不均匀性估计。MRI强度不均匀性可归因于射频线圈的缺陷或与采集序列相关的问题。结果是在图像上产生缓慢变化的阴影伪影，这可能导致基于强度的传统分类产生误差。我们的算法通过修改标准模糊C均值（FCM）算法的目标函数来补偿这种不均匀性，并允许像素（体素）的标记受其邻近邻域标记的影响。邻域效应作为正则化器，使解偏向于分段均匀的标记。这种正则化对于分割受椒盐噪声污染的扫描图像非常有用。给出了合成图像和MR数据的实验结果，以证明所提算法的有效性和效率。

Presents a new semi-automatic method for quantifying regional heart function from two-dimensional echocardiography. In the approach, we first track the endocardial and epicardial boundaries using a new variant of the dynamic snake approach. The tracked borders are then decomposed into clinically meaningful regional parameters, using a novel interpretational shape-space motivated by the 16-segment ...

提出了一种新的半自动方法，用于从二维超声心动图量化局部心脏功能。在该方法中，我们首先使用动态蛇模型的一种新变体追踪心内膜和心外膜边界。然后，利用受16段分割启发的可解释形状空间，将追踪到的边界分解为临床上有意义的局部参数。

Factor analysis is a powerful tool used for the analysis of dynamic studies. One of the major drawbacks of factor analysis of dynamic structures (FADS) is that the solution is not mathematically unique when only nonnegativity constraints are used to determine factors and factor coefficients. In this paper, a method to correct for ambiguous FADS solutions has been developed. A nonambiguous solution...

因子分析是用于动态研究分析的强大工具。动态结构因子分析（FADS）的主要缺点之一是，当仅使用非负约束来确定因子和因子系数时，解在数学上不唯一。本文开发了一种校正模糊FADS解的方法。一个非模糊解...

Demonstration of a technique for three-dimensional (3-D) assessment of tracheal-stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT). S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonization algorithm. Orthogonal to the medial axis the LTT 3-D cross-sectional profile...

展示一种基于螺旋计算机断层扫描（S-CT）的三维（3-D）评估气管狭窄位置、长度和程度的技术。进行S-CT扫描和喉气管道的自动分割后，使用骨架化算法提取喉气管道的中心线。垂直于中心线，得到喉气管道的三维横截面轮廓...

This paper describes a pattern recognition architecture, which we term hierarchical pyramid/neural network (HPNN), that learns to exploit image structure at multiple resolutions for detecting clinically significant features in digital/digitized mammograms. The HPNN architecture consists of a hierarchy of neural networks, each network receiving feature inputs at a given scale as well as features co...

本文描述了一种称为分层金字塔/神经网络（HPNN）的模式识别架构，该架构学习利用多分辨率的图像结构来检测数字/数字化乳腺X线图像中的临床显著特征。HPNN架构由一组分层神经网络组成，每个网络在给定尺度上接收特征输入以及特征共...

A method for the determination of the contrast-agent propagation in vessel trees is presented. A standard three-dimensional (3-D) rotational angiography procedure is performed to reconstruct the morphology of the contrast-filled vessel tree in a 3-D volume. An additional fluoroscopy projection series acquired with a fixed projection angle delivers the temporal information of the bolus propagating....

提出了一种确定血管树中造影剂传播的方法。执行标准的三维旋转血管造影程序，以在三维体积中重建造影剂填充的血管树的形态。使用固定投影角度采集的额外透视投影系列提供了造影剂团块传播的时间信息。

Reconstruction algorithms for transmission tomography have generally assumed that the photons reaching a particular detector bin at a particular angle originate from a single point source. In this paper, we highlight several cases of extended transmission sources, in which it may be useful to approach the estimation of attenuation coefficients as a problem involving multiple transmission point sou...

传输断层扫描的重建算法通常假设在特定角度到达特定探测器单元的来自单个点源。本文强调了扩展传输源的几种情况，在这些情况下，将衰减系数的估计作为一个涉及多个传输点源的问题来处理可能是有用的。