Volume 21, Issue 9

A model-based method for three-dimensional image segmentation was developed and its performance assessed in segmentation of volumetric cardiac magnetic resonance (MR) images and echocardiographic temporal image sequences. Comprehensive design of a three-dimensional (3-D) active appearance model (AAM) is reported for the first time as an involved extension of the AAM framework introduced by Cootes et al. The model's behavior is learned from manually traced segmentation examples during an automated training stage. Information about shape and image appearance of the cardiac structures is contained in a single model. This ensures a spatially and/or temporally consistent segmentation of three-dimensional cardiac images. The clinical potential of the 3-D AAM is demonstrated in short-axis cardiac MR images and four-chamber echocardiographic sequences. The method's performance was assessed by comparison with manually identified independent standards in 56 clinical MR and 64 clinical echo image sequences. The AAM method showed good agreement with the independent standard using quantitative indexes of border positioning errors, endo- and epicardial volumes, and left ventricular mass. In MR, the endocardial volumes, epicardial volumes, and left ventricular wall mass correlation coefficients between manual and AAM were R/sup 2/=0.94,0.97,0.82, respectively. For echocardiographic analysis, the area correlation was R/sup 2/=0.79. The AAM method shows high promise for successful application to MR and echocardiographic image analysis in a clinical setting.

开发了一种基于模型的三维图像分割方法，并在容积心脏磁共振（MR）图像和超声心动图时间序列图像的分割中评估了其性能。首次完整地设计了三维主动外观模型（AAM），作为Cootes等人提出的AAM框架的扩展。该模型的行为在自动训练阶段从手动描记的分割示例中学习。心脏结构形状和图像外观的信息包含在一个单一模型中，确保了三维心脏图像在空间和/或时间上的一致分割。在短轴心脏MR图像和四腔超声心动图序列中展示了3-D AAM的临床潜力。通过与56个临床MR和64个临床超声图像序列中手动识别的独立标准进行比较，评估了方法的性能。使用边界定位误差、心内膜和心外膜容积以及左心室质量的定量指标，AAM方法与独立标准显示出良好的一致性。在MR中，手动与AAM的心内膜容积、心外膜容积和左心室壁质量相关系数分别为R²=0.94、0.97、0.82。对于超声心动图分析，面积相关系数为R²=0.79。AAM方法在临床环境中成功应用于MR和超声心动图图像分析方面显示出很高的前景。

A novel method is introduced for the generation of landmarks for three-dimensional (3-D) shapes and the construction of the corresponding 3-D statistical shape models. Automatic landmarking of a set of manual segmentations from a class of shapes is achieved by 1) construction of an atlas of the class, 2) automatic extraction of the landmarks from the atlas, and 3) subsequent propagation of these l...

介绍了一种用于三维形状地标生成及相应三维统计形状模型构建的新方法。通过1)构建该类形状的图谱，2)从图谱中自动提取地标，3)随后将这些地标传播到...来实现对一类形状的手动分割的自动地标标记。

In this paper, the current status of cardiac image registration methods is reviewed. The combination of information from multiple cardiac image modalities, such as magnetic resonance imaging, computed tomography, positron emission tomography, single-photon emission computed tomography, and ultrasound, is of increasing interest in the medical community for physiologic understanding and diagnostic p...

本文综述了心脏图像配准方法的现状。结合多种心脏图像模态的信息，如磁共振成像、计算机断层扫描、正电子发射断层扫描、单光子发射计算机断层扫描和超声，在医学界越来越受到关注，用于生理学理解和诊断等目的。

This paper describes a quantitative assessment of respiratory motion of the heart and the construction of a model of respiratory motion. Three-dimensional magnetic resonance scans were acquired on eight normal volunteers and ten patients. The volunteers were imaged at multiple positions in the breathing cycle between full exhalation and full inhalation while holding their breath. The exhalation vo...

本文描述了对心脏呼吸运动的定量评估以及呼吸运动模型的构建。对八名正常志愿者和十名患者进行了三维磁共振扫描。志愿者在屏气状态下于完全呼气和完全吸气之间的呼吸周期多个位置进行成像。呼气卷...

Ultrasonic imaging is the noninvasive clinical imaging modality of choice for diagnosing heart disease. At present, two-dimensional ultrasonic grayscale images provide a relatively cheap, fast, bedside method to study the morphology of the heart. Several methods have been proposed to assess myocardial function. These have been based on either grayscale or motion (velocity) information measured in ...

超声成像是诊断心脏疾病的首选无创临床成像方式。目前，二维超声灰度图像提供了一种相对廉价、快速、床边的方法来研究心脏形态。已经提出了几种评估心肌功能的方法。这些方法基于灰度或运动（速度）信息测量...

In this paper, we apply the channelized Hotelling observer (CHO) using a defect detection task to the optimization and evaluation of three-dimensional iterative reconstruction-based compensation methods for myocardial perfusion single-photon emission computed tomography (SPECT). We used a population of 24 mathematical cardiac-torso phantoms that realistically model the activity and attenuation dis...

本文中，我们使用缺陷检测任务的信道化Hotelling观察者（CHO）应用于心肌灌注单光子发射计算机断层扫描（SPECT）的三维迭代重建补偿方法的优化与评估。我们使用了24个数学心脏躯干体模群体，其真实模拟了活度和衰减分布...

Activation time (AT) imaging from electrocardiographic (ECG) mapping data has been developing for several years. By coupling ECG mapping and three-dimensional (3-D) + time anatomical data, the electrical excitation sequence can be imaged completely noninvasively in the human heart. In this paper, a bidomain theory-based surface heart model AT imaging approach was applied to single-beat data of atr...

通过心电图（ECG）标测数据对激活时间（AT）进行成像已发展数年。结合ECG标测和三维（3-D）+时间解剖数据，可以在人体心脏中完全无创地成像电兴奋序列。本文应用基于双域理论的表面心脏模型AT成像方法，处理房颤...的单搏数据。

The application of level set techniques to echocardiographic data is presented. This method allows semiautomatic segmentation of heart chambers, which regularizes the shapes and improves edge fidelity, especially in the presence of gaps, as is common in ultrasound data. The task of the study was to reconstruct left ventricular shape and to evaluate left ventricular volume. Data were acquired with ...

介绍了水平集技术在超声心动图数据中的应用。该方法允许半自动分割心腔，能够规则化形状并提高边缘保真度，尤其是在超声数据中常见的间隙存在时。研究的任务是重建左心室形状并评估左心室容积。数据采集使用...

Quantitative functional analysis of the left ventricle plays a very important role in the diagnosis of heart diseases. While in standard two-dimensional echocardiography this quantification is limited to rather crude volume estimation, three-dimensional (3-D) echocardiography not only significantly improves its accuracy but also makes it possible to derive valuable additional information, like var...

左心室定量功能分析在心脏疾病的诊断中起着非常重要的作用。在标准的二维超声心动图中，这种量化仅限于较为粗略的容积估计，而三维超声心动图不仅显著提高了其准确性，还可以获得有价值的额外信息，例如...

This paper is concerned with the three-dimensional (3-D) reconstruction of coronary vessel centerlines and with how distortion of X-ray angiographic images affects it. Angiographies suffer from pincushion and other geometrical distortions, caused by the peripheral concavity of the image intensifier (II) and the nonlinearity of electronic acquisition devices. In routine clinical practice, where a f...

本文关注冠状动脉中心线的三维重建以及X射线血管造影图像畸变对其的影响。血管造影存在枕形畸变和其他几何畸变，这些畸变由图像增强器（II）的周围凹度和电子采集设备的非线性引起。在常规临床实践中，由于...（原文后续内容未提供）

Image processing was used as a fundamental tool to derive motion information from magnetic resonance (MR) images, which was fed back into prospective respiratory motion correction during subsequent data acquisition to improve image quality in coronary MR angiography (CMRA) scans. This reduces motion artifacts in the images and, in addition, enables the usage of a broader gating window than commonl...

图像处理被用作从磁共振（MR）图像中提取运动信息的基本工具，这些信息被反馈到后续数据采集过程中的前瞻性呼吸运动校正中，以改善冠状MR血管造影（CMRA）扫描的图像质量。这减少了图像中的运动伪影，此外，还允许使用比通常更宽的门控窗口...

Wavelet-based methods have become most popular for the compression of two-dimensional medical images and sequences. The standard implementations consider data sizes that are powers of two. There is also a large body of literature treating issues such as the choice of the "optimal" wavelets and the performance comparison of competing algorithms. With the advent of telemedicine, there is a strong in...

基于小波的方法已成为压缩二维医学图像和序列的最流行方法。标准实现考虑数据大小为2的幂。还有大量文献讨论了如“最优”小波的选择以及竞争算法的性能比较等问题。随着远程医疗的出现，对...

A four-dimensional mapping (three spatial dimensions + time) of myocardial strain-rate would help to describe the mechanical properties of the myocardium, which affect important physiological factors such as the pumping performance of the ventricles. Strain-rate represents the local instantaneous deformation of the myocardium and can be calculated from the spatial gradients of the velocity field. ...

心肌应变率的三维映射（三个空间维度+时间）有助于描述心肌的力学特性，这些特性影响重要的生理因素，如心室的泵血功能。应变率代表心肌的局部瞬时变形，可以从速度场的空间梯度计算得出。...

A new method is proposed to reconstruct and analyze the left ventricle (LV) from multiple acoustic window three-dimensional (3-D) ultrasound acquired using a transthoracic 3-D rotational probe. Prior research in this area has been based on one acoustic window acquisition. However, the data suffers from several limitations that degrade the reconstruction and reduce the clinical value of interpretat...

提出了一种新方法，利用经胸三维旋转探头从多声窗三维超声中重建和分析左心室。先前的研究基于单一声窗采集。然而，该数据存在若干限制，降低了重建质量及其临床解读价值。

A major barrier for using 3-D echocardiography for quantitative analysis of heart function in routine clinical practice is the absence of accurate and robust segmentation and tracking methods necessary to make the analysis automatic. In this paper, we present an automated three-dimensional (3-D) echocardiographic acquisition and image-processing methodology for assessment of left ventricular (LV) ...

在常规临床实践中，使用三维超声心动图进行心脏功能定量分析的一个主要障碍是缺乏准确且稳健的分割和跟踪方法，而这些方法对于实现分析自动化是必要的。在本文中，我们提出了一种自动化的三维超声心动图采集和图像处理方法，用于评估左心室…

Magnetic resonance (MR) tagging is a technique for measuring heart deformations through creation of a stripe grid pattern on cardiac images. In this paper, we present a maximum a posteriori (MAP) framework for detecting tag lines using a Markov random field (MRF) defined on the lattice generated by three-dimensional (3-D) and four-dimensional (4-D) (3-D+t) uniform sampling of B-spline models. In t...

磁共振标记是一种通过在心脏图像上创建条纹网格图案来测量心脏变形的技术。在本文中，我们提出了一个最大后验框架，用于检测标记线，该框架使用定义在由三维和四维（三维+时间）均匀采样B样条模型生成的网格上的马尔可夫随机场。在t...

Echocardiography (cardiac ultrasound) is today the predominant technique for quantitative assessment of cardiac function and valvular heart lesions. Segmentation of cardiac structures is required to determine many important diagnostic parameters. As the heart is a moving organ, reliable information can be obtained only from three-dimensional (3-D) data over time (3-D + time = 4-D). Due to their si...

超声心动图（心脏超声）是目前用于定量评估心功能和瓣膜心脏病变的主要技术。为了确定许多重要的诊断参数，需要对心脏结构进行分割。由于心脏是一个运动器官，只有从随时间变化的三维（3-D）数据（3-D + 时间 = 4-D）才能获得可靠的信息。由于它们的...

This paper presents a virtual tagging framework for measuring, as well as visualising, myocardial deformation using magnetic resonance (MR) velocity imaging. Tagging grids are allocated artificially according to the deformation gradient with varying shapes and densities. The control points are then deformed such that the difference between the induced deformation velocity and that of actually meas...

本文提出了一种虚拟标记框架，用于利用磁共振（MR）速度成像测量和可视化心肌变形。标记网格根据变形梯度人工分配，具有不同的形状和密度。然后对控制点进行变形，使得诱导变形速度与实际测量的速度之间的差异...

The major obstacle of three-dimensional (3-D) echocardiography is that the ultrasound image quality is too low to reliably detect features locally. Almost all available surface-finding algorithms depend on decent quality boundaries to get satisfactory surface models. We formulate the surface model optimization problem in a Bayesian framework, such that the inference made about a surface model is b...

三维超声心动图的主要障碍是超声图像质量太低，无法可靠地局部检测特征。几乎所有可用的表面查找算法都依赖于质量尚可的边界来获得满意的表面模型。我们在贝叶斯框架下制定表面模型优化问题，使得关于表面模型的推断是...