Volume 21, Issue 12

We investigate an approach based on support vector machines (SVMs) for detection of microcalcification (MC) clusters in digital mammograms, and propose a successive enhancement learning scheme for improved performance. SVM is a machine-learning method, based on the principle of structural risk minimization, which performs well when applied to data outside the training set. We formulate MC detection as a supervised-learning problem and apply SVM to develop the detection algorithm. We use the SVM to detect at each location in the image whether an MC is present or not. We tested the proposed method using a database of 76 clinical mammograms containing 1120 MCs. We use free-response receiver operating characteristic curves to evaluate detection performance, and compare the proposed algorithm with several existing methods. In our experiments, the proposed SVM framework outperformed all the other methods tested. In particular, a sensitivity as high as 94% was achieved by the SVM method at an error rate of one false-positive cluster per image. The ability of SVM to outperform several well-known methods developed for the widely studied problem of MC detection suggests that SVM is a promising technique for object detection in a medical imaging application.

我们研究了一种基于支持向量机（SVM）的方法用于数字乳腺X线图像中微钙化（MC）簇的检测，并提出了一种连续增强学习方案以提高性能。SVM是一种基于结构风险最小化原理的机器学习方法，在处理训练集之外的数据时表现良好。我们将MC检测表述为一个监督学习问题，并应用SVM开发检测算法。我们使用SVM来检测图像中每个位置是否存在MC。我们使用包含1120个MC的76例临床乳腺X线图像数据库测试了所提出的方法。我们使用自由响应接收者操作特征曲线来评估检测性能，并将所提出的算法与几种现有方法进行比较。在我们的实验中，所提出的SVM框架优于所有其他测试方法。特别是，SVM方法在每个图像一个假阳性簇的错误率下达到了高达94%的灵敏度。SVM能够优于几种为广泛研究的MC检测问题而开发的知名方法，表明SVM是医学成像应用中物体检测的一种有前景的技术。

This paper presents a new method for image-guided surgery called image-enhanced endoscopy. Registered real and virtual endoscopic images (perspective volume renderings generated from the same view as the endoscope camera using a preoperative image) are displayed simultaneously; when combined with the ability to vary tissue transparency in the virtual images, this provides surgeons with the ability...

本文提出了一种名为图像增强内窥镜的图像引导手术新方法。注册后的真实和虚拟内窥镜图像（使用术前图像从与内窥镜摄像机相同的视角生成的透视体渲染）同时显示；结合虚拟图像中改变组织透明度的能力，这为外科医生提供了...

In this paper, we introduce a concise and concrete definition of an accurate colon centerline and provide an efficient automatic means to extract the centerline and its associated branches (caused by a forceful touching of colon and small bowel or a deep fold in twisted colon lumen). We further discuss its applications on fly-through path planning and endoscopic simulation, as well as its potentia...

本文提出了一种准确结肠中心线的简洁具体定义，并提供了一种高效自动提取中心线及其相关分支（由结肠与小肠强力接触或扭曲结肠管腔深皱褶引起）的方法。我们还进一步讨论了其在飞行路径规划和内镜模拟中的应用，及其潜在...

A fully automated method for computerized detection of pulmonary embolism in spiral computed tomography angiography was developed based on volumetric image analysis. The detection method is based on segmentation of pulmonary vessels to limit the search space, and analysis of several three-dimensional features inside segmented vessel volume. The features utilized are vascular size, local contrast b...

我们开发了一种基于体积图像分析的完全自动化方法，用于在螺旋计算机断层血管造影中检测肺栓塞。该检测方法基于肺血管分割以限制搜索空间，并分析分割血管体积内的多个三维特征。所利用的特征包括血管大小、局部对比度等。

Colorectal cancer can easily be prevented provided that the precursors to tumors, small colonic polyps, are detected and removed. Currently, the only definitive examination of the colon is fiber-optic colonoscopy, which is invasive and expensive. Computed tomographic colonography (CTC) is potentially a less costly and less invasive alternative to FOC. It would be desirable to have computer-aided d...

结直肠癌可以通过检测和切除肿瘤前体——结肠小息肉来轻松预防。目前，结肠的唯一确定性检查是光纤结肠镜检查，该方法具有侵入性且昂贵。计算机断层结肠成像（CTC）可能是FOC的一种成本较低且侵入性较小的替代方案。希望有计算机辅助检测...

An automatic cortical gray matter segmentation from a three-dimensional (3-D) brain images [magnetic resonance (MR) or computed tomography] is a well known problem in medical image processing. In this paper, we first formulate it as a geometric variational problem for propagation of two coupled bounding surfaces. An efficient numerical scheme is then used to implement the geodesic active surface m...

从三维（3D）脑图像（磁共振或计算机断层扫描）中自动分割皮层灰质是医学图像处理中的一个著名问题。本文首先将其表述为两个耦合边界曲面传播的几何变分问题。然后使用高效的数值方案来实现测地活动表面...

Accurate planning of radiation therapy entails the definition of treatment volumes and a clear delimitation of normal tissue of which unnecessary exposure should be prevented. The spinal cord is a radiosensitive organ, which should be precisely identified because an overexposure to radiation may lead to undesired complications for the patient such as neuronal disfunction or paralysis. In this pape...

精准的放射治疗计划需要对治疗靶区进行定义，并明确界定正常组织以避免不必要的照射。脊髓是一个放射敏感器官，必须精确识别，因为过度照射可能导致患者出现神经功能障碍或瘫痪等不良并发症。在本文中...

A feature-guided image interpolation scheme is presented. It is an effective and improved, shape-based interpolation method used for interpolating image slices in medical applications. The proposed method integrates feature line-segments to guide the shape-based method for better shape interpolation. An automatic method for finding these line segments is given. The proposed feature-guided shape-ba...

提出了一种特征引导的图像插值方案。该方案是一种有效且改进的基于形状的插值方法，用于医学应用中的图像切片插值。该方法整合了特征线段来指导基于形状的方法，以实现更好的形状插值。给出了自动寻找这些线段的方法。所提出的特征引导的基于形状的插值方法在形状插值方面优于传统的基于形状的方法。实验中使用了几个医学实例，结果表明该方法在医学图像插值中是有效的。

We present a method for accurate image registration and motion compensation in multidimensional signals, such as two-dimensional (2-D) X-ray images and three-dimensional (3-D) computed tomography/magnetic resonance imaging volumes. The method is based on phase from quadrature filters, which makes it robust to noise and temporal intensity variations. The method is equally applicable to signals of t...

我们提出了一种在多维信号（如二维X光图像和三维计算机断层扫描/磁共振成像体积）中进行精确图像配准和运动补偿的方法。该方法基于正交滤波器的相位，使其对噪声和时间强度变化具有鲁棒性。该方法同样适用于信号等...

Over the last few decades there were dramatic improvements in ultrasound imaging quality with the utilization of harmonic frequencies induced by both tissue and echo-contrast agents. The advantages of harmonic imaging cause rapid penetration of this modality to diverse clinical uses, among which myocardial perfusion determination seems to be the most important application. In order to effectively ...

在过去的几十年里，利用组织和回声造影剂产生的谐波频率，超声成像质量有了显著提高。谐波成像的优势使其迅速渗透到各种临床应用，其中心肌灌注测定似乎是最重要的应用。为了有效...

The human cerebral cortex is topologically equivalent to a sphere when it is viewed as closed at the brain stem. Due to noise and/or resolution issues, magnetic resonance imaging may see "handles" that need to be eliminated to reflect the true spherical topology. Shattuck and Leahy (2001) present an algorithm to correct such an image. The basis for their correction strategy is a conjecture, which ...

当人类大脑皮层在脑干处闭合时，它在拓扑上等价于一个球面。由于噪声和/或分辨率问题，磁共振成像可能会看到需要消除的“手柄”，以反映真实的球面拓扑。Shattuck和Leahy（2001）提出了一种校正此类图像的算法。他们校正策略的基础是一个猜想，该……

Hybrid positron emission tomography (PET) cameras can be used to measure the distribution of positron emitting radionuclides. An important system parameter for Hybrid PET is the appropriate tomographic sampling requirements. In this paper, a previously developed theoretical formulation for quantifying sampling in continuous-to-discrete tomographic systems, termed the "crosstalk matrix," is used to...

混合正电子发射断层扫描（PET）相机可用于测量正电子发射放射性核素的分布。混合PET的一个重要系统参数是合适的断层采样要求。本文采用先前开发的用于量化连续到离散断层系统中采样的理论公式，称为'串扰矩阵'，来...

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 ...

本索引涵盖了本年度该期刊中出现的所有技术项目——论文、通信、评论等，以及往年中被评论或纠正的项目。如果部门和其他项目被认为具有存档价值，也可能被收录。作者索引包含每个项目的主要条目，列在第一作者名下...

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 ...

本索引涵盖了本年度该期刊中出现的所有技术项目——论文、通讯、评论等，以及往年在本年度被评论或更正的项目。如果部门和其他项目被判定具有存档价值，也可能被收录。作者索引包含每个项目的主要条目，列在第一作者名下……