Volume 22, Issue 2

We propose a shape-based approach to curve evolution for the segmentation of medical images containing known object types. In particular, motivated by the work of Leventon, Grimson, and Faugeras (2000), we derive a parametric model for an implicit representation of the segmenting curve by applying principal component analysis to a collection of signed distance representations of the training data. The parameters of this representation are then manipulated to minimize an objective function for segmentation. The resulting algorithm is able to handle multidimensional data, can deal with topological changes of the curve, is robust to noise and initial contour placements, and is computationally efficient. At the same time, it avoids the need for point correspondences during the training phase of the algorithm. We demonstrate this technique by applying it to two medical applications; two-dimensional segmentation of cardiac magnetic resonance imaging (MRI) and three-dimensional segmentation of prostate MRI.

我们提出了一种基于形状的曲线演化方法，用于分割包含已知物体类型的医学图像。具体来说，受Leventon、Grimson和Faugeras（2000）工作的启发，我们通过对训练数据的一组有符号距离表示进行主成分分析，推导出分割曲线隐式表示的参数模型。然后操作该表示的参数以最小化分割的目标函数。该算法能够处理多维数据，处理曲线的拓扑变化，对噪声和初始轮廓放置具有鲁棒性，并且计算效率高。同时，它避免了在算法训练阶段需要点对应。我们通过将该技术应用于两个医学应用来证明其有效性：心脏磁共振成像（MRI）的二维分割和前列腺MRI的三维分割。

In magnetic resonance imaging, magnetic field inhomogeneities cause distortions in images that are reconstructed by conventional fast Fourier transform (FFT) methods. Several noniterative image reconstruction methods are used currently to compensate for field inhomogeneities, but these methods assume that the field map that characterizes the off-resonance frequencies is spatially smooth. Recently,...

在磁共振成像中，磁场不均匀性会导致通过常规快速傅里叶变换（FFT）方法重建的图像出现畸变。目前，有几种非迭代图像重建方法用于补偿场不均匀性，但这些方法假设表征偏共振频率的场图在空间上是平滑的。最近，...

Breast cancer is the most frequently diagnosed malignancy and the second leading cause of mortality in women . In the last decade, ultrasound along with digital mammography has come to be regarded as the gold standard for breast cancer diagnosis. Automatically detecting tumors and extracting lesion boundaries in ultrasound images is difficult due to their specular nature and the variance in shape ...

乳腺癌是女性中最常诊断的恶性肿瘤，也是导致女性死亡的第二大原因。在过去十年中，超声与数字乳腺X线摄影一起被视为乳腺癌诊断的金标准。由于超声图像的镜面性质以及形状的变异，自动检测肿瘤并提取病变边界是困难的...

Presents a novel method for validation of nonrigid medical image registration. This method is based on the simulation of physically plausible, biomechanical tissue deformations using finite-element methods. Applying a range of displacements to finite-element models of different patient anatomies generates model solutions which simulate gold standard deformations. From these solutions, deformed ima...

提出了一种验证非刚性医学图像配准的新方法。该方法基于使用有限元方法模拟物理上合理的生物力学组织变形。对不同的患者解剖结构的有限元模型施加一系列位移，生成模拟黄金标准变形的模型解。从这些解中，得到变形图像...

The phase correlation method (PCM) is known to provide straightforward estimation of rigid translational motion between two images. It is often claimed that the original method is best suited to identify integer pixel displacements, which has prompted the development of numerous subpixel displacement identification methods. However, the fact that the phase correlation matrix is rank one for a nois...

相位相关法（PCM）能够直接估计两幅图像之间的刚性平移运动。通常认为原始方法最适合识别整数像素位移，这促使了众多亚像素位移识别方法的发展。然而，相位相关矩阵对于无噪声情况是秩为1的...

Inhaled hyperpolarized helium-3 (/sup 3/He) gas is a new magnetic resonance (MR) contrast agent that is being used to study lung functionality. To evaluate the total lung ventilation from the hyperpolarized /sup 3/He MR images, it is necessary to segment the lung cavities. This is difficult to accomplish using only the hyperpolarized /sup 3/He MR images, so traditional proton (/sup 1/H) MR images ...

吸入超极化氦-3（/sup 3/He）气体是一种新型磁共振（MR）对比剂，正在被用于研究肺功能。为了从超极化/sup 3/He MR图像中评估总肺通气量，需要分割肺腔。仅使用超极化/sup 3/He MR图像难以完成，因此传统质子（/sup 1/H）MR图像...

We investigate the introduction of cortical constraints for non rigid intersubject brain registration. We extract sulcal patterns with the active ribbon method, presented by Le Goualher et al. (1997). An energy based registration method (Hellier et al., 2001), which will be called photometric registration method in this paper, makes it possible to incorporate the matching of cortical sulci. The lo...

我们研究了引入皮质约束用于非刚性个体间脑部配准。我们使用Le Goualher等人（1997）提出的活动带方法提取沟模式。一种基于能量的配准方法（Hellier等人，2001），在本文中称为光度配准方法，使得整合皮质沟的匹配成为可能。该方法...

We quantitatively compare filtered backprojection (FBP), expectation-maximization (EM), and Bayesian reconstruction algorithms as applied to the IndyPET scanner-a dedicated research scanner which has been developed for small and intermediate field of view imaging applications. In contrast to previous approaches that rely on Monte Carlo simulations, a key feature of our investigation is the use of ...

我们定量比较了滤波反投影（FBP）、期望最大化（EM）和贝叶斯重建算法在IndyPET扫描仪上的应用——这是一种专为小视野和中视野成像应用而开发的研究专用扫描仪。与以往依赖蒙特卡洛模拟的方法不同，我们研究的一个关键特征是使用了…

Breast cancer diagnosis through ultrasound tissue characterization was studied using receiver operating characteristic (ROC) analysis of combinations of acoustic features, patient age, and radiological findings. A feature fusion method was devised that operates even if only partial diagnostic data are available. The ROC methodology uses ordinal dominance theory and bootstrap resampling to evaluate...

通过超声组织定征进行乳腺癌诊断的研究，采用接受者操作特征（ROC）分析声学特征、患者年龄和放射学发现的组合。设计了一种特征融合方法，即使在只有部分诊断数据可用时也能运行。ROC方法使用序数优势理论和自助重采样来评估...

In this paper, a model-based approach to medical image analysis is presented. It is aimed at understanding the influence of the physiological (related to tissue) and physical (related to image modality) processes underlying the image content. This methodology is exemplified by modeling first, the liver and its vascular network, and second, the standard computed tomography (CT) scan acquisition. Af...

本文提出了一种基于模型的医学图像分析方法。旨在理解生理（与组织相关）和物理（与图像模态相关）过程对图像内容的影响。该方法首先通过建模肝脏及其血管网络，然后建模标准计算机断层扫描（CT）采集过程来举例说明。Af...

This paper characterizes factors affecting the accuracy of the correlation coefficient (CC) template matching algorithm, as applied to motion tracking from two-dimensional real-time coronary artery magnetic resonance images. The performance of this algorithm is analyzed in the presence of both random and systematic error. In the presence of random error, it is shown that a necessary and sufficient...

本文描述了影响相关系数模板匹配算法准确性的因素，该算法应用于二维实时冠状动脉磁共振图像的运动跟踪。分析了该算法在随机误差和系统误差存在下的性能。在随机误差存在下，表明充分且必要的...

We present a new class of approaches for rigid-body registration and their evaluation in studying multiple sclerosis (MS) via multiprotocol magnetic resonance imaging (MRI). Three pairs of rigid-body registration algorithms were implemented, using cross-correlation and mutual information (MI), operating on original gray-level images, and utilizing the intermediate images resulting from our new sca...

我们提出了一类新的刚体配准方法及其在通过多协议磁共振成像（MRI）研究多发性硬化（MS）中的评估。

A technique, based on echo planar imaging (EPI)-based phase modulation factor maps, is described for correction of EPI distortions resulting from field inhomogeneity. In this paper, a phase modulation factor was employed to remove the distortions. The phase modulation factor was obtained experimentally by collecting EPI images with a spin-echo (TE) spacing, /spl Delta/TE, equal to the inter-echo t...

描述了一种基于回波平面成像（EPI）相位调制因子图的技术，用于校正由场不均匀性引起的EPI畸变。本文采用相位调制因子来消除畸变。通过收集自旋回波（TE）间隔ΔTE等于回波间时间...的EPI图像，实验获得相位调制因子。