Volume 18, Issue 10

Describes a fully automated method for model-based tissue classification of magnetic resonance (MR) images of the brain. The method interleaves classification with estimation of the model parameters, improving the classification at each iteration. The algorithm is able to segment single- and multi-spectral MR images, corrects for MR signal inhomogeneities, and incorporates contextual information by means of Markov random Fields (MRF's). A digital brain atlas containing prior expectations about the spatial location of tissue classes is used to initialize the algorithm. This makes the method fully automated and therefore it provides objective and reproducible segmentations. The authors have validated the technique on simulated as well as on real MR images of the brain.

描述了一种完全自动化的方法，用于对脑部磁共振（MR）图像进行基于模型的组织分类。该方法将分类与模型参数估计交错进行，每次迭代均改进分类。该算法能够分割单谱和多谱MR图像，校正MR信号不均匀性，并利用马尔可夫随机场（MRF）纳入上下文信息。使用包含组织类别空间位置先验知识的数字脑图谱来初始化算法。这使得该方法完全自动化，从而提供客观且可重复的分割结果。作者已在模拟和真实脑部MR图像上验证了该技术。

The authors propose a model-based method for fully automated bias field correction of MR brain images. The MR signal is modeled as a realization of a random process with a parametric probability distribution that is corrupted by a smooth polynomial inhomogeneity or bias field. The method the authors propose applies an iterative expectation-maximization (EM) strategy that interleaves pixel classifi...

作者提出了一种基于模型的方法，用于全自动校正MR脑图像的偏置场。MR信号被建模为一个随机过程的实现，该过程具有参数化概率分布，并受到平滑多项式非均匀性或偏置场的干扰。作者提出的方法应用了迭代期望最大化（EM）策略，该策略交错进行像素分类...

This paper presents a new technique for the automatic model-based segmentation of three-dimensional (3-D) objects from volumetric image data. The development closely follows the seminal work of Taylor and Cootes on active shape models, but is based on a hierarchical parametric object description rather than a point distribution model. The segmentation system includes both the building of statistic...

本文提出了一种新的自动模型分割三维物体来自体积图像数据的技术。该发展紧密遵循Taylor和Cootes在主动形状模型方面的开创性工作，但基于分层参数化对象描述而非点分布模型。分割系统包括统计...

Quantification of the degree of stenosis or vessel dimensions are important for diagnosis of vascular diseases and planning vascular interventions. Although diagnosis from three-dimensional (3-D) magnetic resonance angiograms (MRA's) is mainly performed on two-dimensional (2-D) maximum intensity projections, automated quantification of vascular segments directly from the 3-D dataset is desirable t...

量化狭窄程度或血管尺寸对于诊断血管疾病和规划血管介入治疗非常重要。尽管从三维（3-D）磁共振血管造影（MRA）图像进行诊断主要基于二维（2-D）最大强度投影，但直接从三维数据集自动量化血管段是理想的...

A model of object shape by nets of medial and boundary primitives is justified as richly capturing multiple aspects of shape and yet requiring representation space and image analysis work proportional to the number of primitives. Metrics are described that compute an object representation's prior probability of local geometry by reflecting variabilities in the net's node and link parameter values,...

提出了一种由中轴和边界基元网络构成的对象形状模型，该模型能够丰富地捕捉形状的多个方面，同时所需的表示空间和图像分析工作量与基元数量成正比。描述了通过反映网络节点和链接参数值的变异性来计算对象表示局部几何先验概率的度量。

The cortex is the outermost thin layer of gray matter in the brain; geometric measurement of the cortex helps in understanding brain anatomy and function. In the quantitative analysis of the cortex from MR images, extracting the structure and obtaining a representation for various measurements are key steps. While manual segmentation is tedious and labor intensive, automatic reliable efficient seg...

皮层是大脑最外层的薄层灰质；皮层的几何测量有助于理解大脑解剖和功能。在MR图像的皮层定量分析中，提取结构并获取用于各种测量的表示是关键步骤。手动分割繁琐且劳动密集，而自动、可靠、高效的分割...

The study presented in this paper tests the hypothesis that the combination of a global similarity transformation and local free-form deformations can be used for the accurate segmentation of internal structures in MR images of the brain. To quantitatively evaluate the authors' approach, the entire brain, the cerebellum, and the head of the caudate have been segmented manually by two raters on one...

本文提出的研究检验了以下假设：全局相似性变换与局部自由形式变形的结合可用于精确分割脑部MR图像中的内部结构。为了定量评估作者的方法，由两名评估者对一名...上的整个大脑、小脑和尾状核头进行了手动分割。

Deformable models, which include deformable contours (the popular snakes) and deformable surfaces, are a powerful model-based medical image analysis technique. The authors develop a new class of deformable models by formulating deformable surfaces in terms of an affine cell image decomposition (ACID). The authors' approach significantly extends standard deformable surfaces, while retaining their i...

可变形模型，包括可变形轮廓（流行的蛇形模型）和可变形曲面，是一种强大的基于模型的医学图像分析技术。作者通过仿射细胞图像分解（ACID）来构建可变形曲面，从而开发了一类新的可变形模型。作者的方法显著拓展了标准可变形曲面，同时保留了其...

A better knowledge of the kinematics behavior of total knee replacement (TKR) during activity still remains a crucial issue to validate innovative prosthesis designs and different surgical strategies. Tools for more accurate measurement of in vivo kinematics of knee prosthesis components are therefore fundamental to improve the clinical outcome of knee replacement. In the present study, a novel mo...

更好地了解全膝关节置换术（TKR）在活动中的运动学行为仍然是验证创新假体设计和不同手术策略的关键问题。因此，用于更准确测量膝关节假体组件体内运动学的工具对于改善膝关节置换的临床结果至关重要。在本研究中，一种新颖的...

A three-dimensional (3-D) representation of cerebral vessel morphology is essential for neuroradiologists treating cerebral aneurysms. However, current imaging techniques cannot provide such a representation. Slices of MR angiography (MRA) data can only give two-dimensional (2-D) descriptions and ambiguities of aneurysm position and size arising in X-ray projection images can often be intractable....

三维（3-D）脑部血管形态表示对于治疗脑动脉瘤的神经放射学家至关重要。然而，当前的成像技术无法提供这样的表示。磁共振血管成像（MRA）数据的切片只能提供二维（2-D）描述，而X射线投影图像中出现的动脉瘤位置和大小的歧义往往难以处理……

Image-guided neurosurgery relies on accurate registration of the patient, the preoperative image series, and the surgical instruments in the same coordinate space. Recent clinical reports have documented the magnitude of gravity-induced brain deformation in the operating room and suggest these levels of tissue motion may compromise the integrity of such systems. The authors are investigating a mod...

图像引导神经外科依赖于患者、术前图像序列和手术器械在相同坐标空间中的精确配准。最近的临床报告记录了手术室中重力诱导脑变形的程度，并表明这种组织运动水平可能损害此类系统的完整性。作者正在研究一种模型更新图像引导方法，该方法通过使用患者特定的有限元模型预测变形，将术前图像与手术中的实际情况进行配准。本文报告了该方法在脑肿瘤手术中的初步临床应用，并讨论了当前实施中的挑战和观察结果。

The accuracy of image-guided neurosurgery generally suffers from brain deformations due to intraoperative changes. These deformations cause significant changes of the anatomical geometry (organ shape and spatial interorgan relations), thus making intraoperative navigation based on preoperative images error prone. In order to improve the navigation accuracy, the authors developed a biomechanical mo...

图像引导神经外科的准确性通常受到术中变化导致的脑变形的影响。这些变形会引起解剖几何（器官形状和空间器官间关系）的显著变化，从而使基于术前图像的术中导航容易出错。为了提高导航精度，作者开发了一种生物力学模型...

Accurate delineation of the volumetric motion of the left ventricle (LV) of the heart from tagged magnetic resonance imaging (MRI) is an important area of research. The authors have built a system that takes extracted tag line features from short axis (SA) and long axis (LA) image sequences as input and fits a four-dimensional (4-D) time-varying B-spline model to the data by simultaneously fitting...

从标记磁共振成像（MRI）准确描绘心脏左心室（LV）的体积运动是一个重要的研究领域。作者构建了一个系统，该系统将短轴（SA）和长轴（LA）图像序列中提取的标记线特征作为输入，并通过同时拟合数据来拟合一个四维（4-D）时变B样条模型。

A method for extraction and labeling of the coronary arterial tree (CAT) using minimal user supervision in single-view angiograms is proposed. The CAT structural description (skeleton and borders) is produced, along with quantitative information for the artery dimensions and assignment of coded labels, based on a given coronary artery model represented by a graph. The stages of the method are: (1)...

提出了一种在单视角血管造影图中使用最小用户监督提取和标记冠状动脉树的方法。该方法生成冠状动脉树的结构描述（骨架和边界），以及动脉尺寸的定量信息和基于给定冠状动脉模型（以图形表示）的编码标签分配。该方法的阶段包括：(1)...

Computerized analysis of the tongue surface movement can provide valuable information to speech and swallowing research. Ultrasound technology is currently the most attractive modality for the tongue imaging mainly because of its high video frame rate. However, problems with ultrasound imaging, such as noise and echo artifacts, refractions, and unrelated reflections pose significant challenges for...

舌头表面运动的计算机化分析可以为言语和吞咽研究提供有价值的信息。超声技术目前是舌头成像最具吸引力的模态，主要因为其高视频帧率。然而，超声成像的问题，如噪声和回声伪影、折射以及无关反射，给...带来了重大挑战。

For pt. I see ibid., vol. 18, no. 10, p. 909-16 (1999). Studies aimed at quantifying neuroanatomical differences between populations require the volume measurements of individual brain structures. If the study contains a large number of images, manual segmentation is not practical. This study tests the hypothesis that a fully automatic, atlas-based segmentation method can be used to quantify atrop...

第一部分见于同刊第18卷第10期第909-916页（1999年）。旨在量化人群之间神经解剖学差异的研究需要测量单个大脑结构的体积。如果研究中包含大量图像，手动分割并不实用。本研究测试了以下假设：一种全自动的、基于图谱的分割方法可用于量化萎缩...

A method is proposed for the automatic, rapid, and stable identification and measurement of objects in three-dimensional (3-D) images. It is based on local shape properties derived statistically from populations of medial primitives sought throughout the image space. These shape properties are measured at medial locations within the object and include scale, orientation, endness, and medial dimens...

提出了一种在三维图像中自动、快速且稳定地识别和测量目标的方法。该方法基于从图像空间中搜索的中轴原始形状的统计局部形状属性。这些形状属性在目标内部的中轴位置测量，包括尺度、方向、末端性和中轴维度。

A method has been developed to reconstruct three-dimensional (3-D) surfaces from two-dimensional (2-D) projection data. It is used to produce individualized boundary element models, consisting of thorax and lung surfaces, for electro- and magnetocardiographic inverse problems. Two orthogonal projections are utilized. A geometrical prior model, built using segmented magnetic resonance images, is de...

开发了一种从二维投影数据重建三维表面的方法。该方法用于生成个性化的边界元模型，包括胸部和肺部表面，用于心电和心磁逆问题。利用两个正交投影。使用分割的磁共振图像构建的几何先验模型...

The endovascular coil embolization of intracranial saccular aneurysms requires a set of specific X-ray images with which to view the aneurysm during coiling. These two-dimensional (2-D) images, known as working projections, should be optimal for measuring the aneurysm sac diameter, inserting the first coil, and checking coil overhang into the surrounding vessels. At present the gantry tilt that pr...

颅内囊状动脉瘤的血管内线圈栓塞需要一组特定的X射线图像，以便在栓塞过程中观察动脉瘤。这些二维（2D）图像，称为工作投影，应最优用于测量动脉瘤囊直径、插入第一个线圈以及检查线圈突出到周围血管的情况。目前，机架倾斜...

Microcalcifications can be one of the earliest signs of breast cancer. Unfortunately, their appearance in mammograms can be mimicked by dust and dirt entering the imaging process and this has been shown previously to lead to false positives. The authors use a model of the imaging process and, in particular, the blurring functions inherent within it to detect the film-screen artifacts caused by dus...

微钙化可能是乳腺癌最早的体征之一。不幸的是，它们在乳腺X线照片中的表现可能被进入成像过程的灰尘和污垢所模仿，而此前已有研究表明这会导致假阳性结果。作者使用了成像过程模型，尤其是其中固有的模糊函数，来检测由灰尘引起的胶片-屏幕伪影...