Volume 24, Issue 12

This paper presents a validation study on statistical nonsupervised brain tissue classification techniques in magnetic resonance (MR) images. Several image models assuming different hypotheses regarding the intensity distribution model, the spatial model and the number of classes are assessed. The methods are tested on simulated data for which the classification ground truth is known. Different noise and intensity nonuniformities are added to simulate real imaging conditions. No enhancement of the image quality is considered either before or during the classification process. This way, the accuracy of the methods and their robustness against image artifacts are tested. Classification is also performed on real data where a quantitative validation compares the methods' results with an estimated ground truth from manual segmentations by experts. Validity of the various classification methods in the labeling of the image as well as in the tissue volume is estimated with different local and global measures. Results demonstrate that methods relying on both intensity and spatial information are more robust to noise and field inhomogeneities. We also demonstrate that partial volume is not perfectly modeled, even though methods that account for mixture classes outperform methods that only consider pure Gaussian classes. Finally, we show that simulated data results can also be extended to real data.

本文对磁共振（MR）图像中无监督统计脑组织分类技术进行了验证研究。评估了几种基于不同假设的图像模型，这些假设涉及强度分布模型、空间模型和类别数量。这些方法在已知分类真实标签的模拟数据上进行测试。添加了不同的噪声和强度不均匀性以模拟真实的成像条件。在分类过程之前或期间不考虑图像质量增强。这样，测试了方法的准确性及其对图像伪影的鲁棒性。还在真实数据上进行了分类，通过定量验证将方法的结果与专家手动分割的估计真实标签进行比较。使用不同的局部和全局度量来评估各种分类方法在图像标记和组织体积方面的有效性。结果表明，依赖强度和空间信息的方法对噪声和场不均匀性更鲁棒。我们还表明，即使考虑混合类别的方法优于仅考虑纯高斯类别的方法，部分体积也没有被完美建模。最后，我们展示了模拟数据的结果也可以推广到真实数据。

The segmentation of the human airway tree from volumetric computed tomography (CT) images builds an important step for many clinical applications and for physiological studies. Previously proposed algorithms suffer from one or several problems: leaking into the surrounding lung parenchyma, the need for the user to manually adjust parameters, excessive runtime. Low-dose CT scans are increasingly ut...

从体层计算机断层扫描（CT）图像中分割人体气道树，是许多临床应用和生理学研究的重要步骤。先前提出的算法存在一个或多个问题：泄漏到周围肺实质、需要用户手动调整参数、运行时间过长。低剂量CT扫描正越来越多地被用于...

Prostatic adenocarcinoma is the most commonly occurring cancer among men in the United States, second only to skin cancer. Currently, the only definitive method to ascertain the presence of prostatic cancer is by trans-rectal ultrasound (TRUS) directed biopsy. Owing to the poor image quality of ultrasound, the accuracy of TRUS is only 20%-25%. High-resolution magnetic resonance imaging (MRI) has b...

前列腺腺癌是美国男性最常见癌症，仅次于皮肤癌。目前，确定前列腺癌存在的唯一确切方法是经直肠超声（TRUS）引导活检。由于超声图像质量差，TRUS的准确率仅为20%-25%。高分辨率磁共振成像（MRI）已...

Matching of corresponding branchpoints between two human airway trees, as well as assigning anatomical names to the segments and branchpoints of the human airway tree, are of significant interest for clinical applications and physiological studies. In the past, these tasks were often performed manually due to the lack of automated algorithms that can tolerate false branches and anatomical variabil...

在两个人类气道树之间匹配相应的分支点，并为人类气道树的段和分支点分配解剖名称，对于临床应用和生理研究具有重要意义。过去，由于缺乏能够容忍假分支和解剖变异性的自动化算法，这些任务通常手动完成。

It has recently become possible to simulate aneurysmal blood flow dynamics in a patient-specific manner via the coupling of three-dimensional (3-D) X-ray angiography and computational fluid dynamics (CFD). Before such image-based CFD models can be used in a predictive capacity, however, it must be shown that they indeed reproduce the in vivo hemodynamic environment. Motivated by the fact that ther...

最近，通过将三维X射线血管造影与计算流体动力学（CFD）相结合，已经能够以患者特异性的方式模拟动脉瘤血流动力学。然而，在这种基于图像的CFD模型用于预测之前，必须证明它们确实再现了体内血流动力学环境。受此激励...

Recent advances in micro-magnetic resonance imaging have shown the possibility of in vivo assessment of trabecular bone architecture. However, the small feature size and relatively low signal-to-noise ratio (SNR) achievable in vivo cause the intensity histogram to be unimodal. The critical first step in the processing of these images is the extraction of bone volume fraction for each voxel. Here, ...

微磁共振成像的最新进展表明，体内评估骨小梁结构成为可能。然而，体内可达到的小特征尺寸和相对较低的信噪比导致强度直方图呈单峰分布。处理这些图像的关键第一步是提取每个体素的骨体积分数。这里，...

Traditional chromosome imaging has been limited to grayscale images, but recently a 5-fluorophore combinatorial labeling technique (M-FISH) was developed wherein each class of chromosomes binds with a different combination of fluorophores. This results in a multispectral image, where each class of chromosomes has distinct spectral components. In this paper, we develop new methods for automatic chr...

传统的染色体成像仅限于灰度图像，但最近开发了一种5荧光团组合标记技术（M-FISH），其中每类染色体结合不同的荧光团组合。这产生了多光谱图像，其中每类染色体具有不同的光谱成分。本文发展了新的自动染色体...方法。

For the 2-class detection problem (signal absent/present), the likelihood ratio is an ideal observer in that it minimizes Bayes risk for arbitrary costs and it maximizes the area under the receiver operating characteristic (ROC) curve [AUC]. The AUC-optimizing property makes it a valuable tool in imaging system optimization. If one considered a different task, namely, joint detection and localizat...

对于二类检测问题（信号不存在/存在），似然比是一种理想观测器，因为它能在任意代价下最小化贝叶斯风险，并且最大化接收者操作特征（ROC）曲线下面积[AUC]。AUC最大化性质使其成为成像系统优化中的宝贵工具。如果考虑不同的任务，即联合检测和定位...

The effects of penetration are included in the formulas for the prediction of the resolution of pinhole collimators through the use of effective diameters. Expressions of the resolution-effective diameter for pinholes with a double-knife-edge (DKE) profile are available in the literature. In this paper the expressions applicable to asymmetric-knife-edge (AKE) profiles, which include the important ...

穿透效应包含在预测针孔准直器分辨率的公式中，通过使用有效直径。文献中已有双刀边（DKE）轮廓针孔的有效直径表达式。本文推导了适用于非对称刀边（AKE）轮廓的表达式，其中包括重要的...

We are attempting to develop expressions for the coordinates of points on the three-class ideal observer's receiver operating characteristic (ROC) hypersurface as functions of the set of decision criteria used by the ideal observer. This is considerably more difficult than in the two-class classification task, because the conditional probabilities in question are not simply related to the cumulati...

我们试图给出三分类理想观察者接收者操作特征（ROC）超曲面上点的坐标表达式，这些表达式作为理想观察者使用的决策准则集的函数。这比二分类任务要困难得多，因为所涉及的条件概率与累积概率的关系并不简单...

This paper reports a new delay subspace decomposition (DSD) algorithm. Instead of using the canonical zero-delay correlation matrix, the new DSD algorithm introduces a delay into the correlation matrix of the subspace decomposition to suppress noises in the data. The algorithm is applied to functional magnetic resonance imaging (fMRI) to detect the regions of focal activities in the brain. The eff...

本文报道了一种新的延迟子空间分解（DSD）算法。与传统的零延迟相关矩阵不同，新的DSD算法在子空间分解的相关矩阵中引入延迟，以抑制数据中的噪声。该算法应用于功能磁共振成像（fMRI），以检测大脑中的局灶活动区域。实验结果表明...

Provides a listing of current staff, committee members and society officers.

提供当前工作人员、委员会成员和学会官员的列表。

Presents the table of contents for this issue of the periodical.

呈现本期期刊的目录。

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author's ...

本索引涵盖了该期刊在年内发表的所有技术性文章——论文、通讯、评论等，以及此前年份发表但在本年内被评论或更正的文章。如果部门和其它项目被认为具有存档价值，也可能被收录。作者索引列出了每篇文章的主要条目，按第一作者姓名排列……

This page or pages intentionally left blank.

本页或这些页故意留为空白。

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

热忱邀请有意投稿的作者提交新的、未发表的手稿，以收录于本次征稿通知所描述的即将举行的活动中。

Provides instructions and guidelines to prospective authors who wish to submit manuscripts.

为希望提交稿件的新作者提供说明和指南。