Volume 22, Issue 8

An overview is presented of the medical image processing literature on mutual-information-based registration. The aim of the survey is threefold: an introduction for those new to the field, an overview for those working in the field, and a reference for those searching for literature on a specific application. Methods are classified according to the different aspects of mutual-information-based registration. The main division is in aspects of the methodology and of the application. The part on methodology describes choices made on facets such as preprocessing of images, gray value interpolation, optimization, adaptations to the mutual information measure, and different types of geometrical transformations. The part on applications is a reference of the literature available on different modalities, on interpatient registration and on different anatomical objects. Comparison studies including mutual information are also considered. The paper starts with a description of entropy and mutual information and it closes with a discussion on past achievements and some future challenges.

本文对基于互信息的医学图像配准文献进行了概述。本综述旨在三个方面：为初入该领域者提供介绍，为领域内工作者提供概览，为寻找特定应用文献者提供参考。方法根据基于互信息配准的不同方面进行分类。主要分为方法论和应用两个方面。方法论部分描述了在图像预处理、灰度插值、优化、互信息测度的适应性调整以及不同类型的几何变换等方面的选择。应用部分提供了关于不同模态、患者间配准及不同解剖对象的文献参考。还包括了涉及互信息的比较研究。文章从熵和互信息的描述开始，以对过去成就和未来挑战的讨论结束。

We describe an automated method to locate the optic nerve in images of the ocular fundus. Our method uses a novel algorithm we call fuzzy convergence to determine the origination of the blood vessel network. We evaluate our method using 31 images of healthy retinas and 50 images of diseased retinas, containing such diverse symptoms as tortuous vessels, choroidal neovascularization, and hemorrhages...

我们描述了一种自动定位眼底图像中视神经的方法。该方法使用一种我们称之为模糊收敛的新算法来确定血管网络的起点。我们使用31张健康视网膜图像和50张患病视网膜图像评估了该方法，这些图像包含各种症状，如迂曲血管、脉络膜新生血管和出血等。

In this paper, we show how the concept of statistical deformation models (SDMs) can be used for the construction of average models of the anatomy and their variability. SDMs are built by performing a statistical analysis of the deformations required to map anatomical features in one subject into the corresponding features in another subject. The concept of SDMs is similar to statistical shape mode...

本文展示了如何利用统计变形模型（SDM）的概念来构建平均解剖模型及其变异性。SDM通过对将一个受试者的解剖特征映射到另一个受试者相应特征所需的变形进行统计分析来构建。SDM的概念类似于统计形状模型...

The lungs exchange air with the external environment via the pulmonary airways. Computed tomography (CT) scanning can be used to obtain detailed images of the pulmonary anatomy, including the airways. These images have been used to measure airway geometry, study airway reactivity, and guide surgical interventions. Prior to these applications, airway segmentation can be used to identify the airway ...

肺部通过气道与外界交换空气。计算机断层扫描（CT）可用于获取包括气道在内的肺部解剖结构的详细图像。这些图像已被用于测量气道几何形状、研究气道反应性以及指导手术干预。在这些应用之前，气道分割可用于识别气道...

In this paper, a method of acquiring intraoperative data using a laser range scanner (LRS) is presented within the context of model-updated image-guided surgery. Registering textured point clouds generated by the LRS to tomographic data is explored using established point-based and surface techniques as well as a novel method that incorporates geometry and intensity information via mutual informat...

本文在模型更新图像引导手术的背景下，提出了一种使用激光范围扫描仪（LRS）获取术中数据的方法。探讨了将LRS生成的纹理点云与断层图像数据配准的方法，包括现有的基于点和表面的技术，以及一种通过互信息结合几何和强度信息的新方法。

In recent years, several methods have been proposed for constructing statistical shape models to aid image analysis tasks by providing a priori knowledge. Examples include principal component analysis of manually or semiautomatically placed corresponding landmarks on the learning shapes [point distribution models (PDMs)], which is time consuming and subjective. However, automatically establishing ...

近年来，已经提出了几种方法来构建统计形状模型，通过提供先验知识来辅助图像分析任务。例子包括对学习形状上手动或半自动放置的对应地标进行主成分分析[点分布模型（PDMs）]，这既耗时又主观。然而，自动建立...

A method is presented to extract and track the position of a guide wire during endovascular interventions under X-ray fluoroscopy. The method can be used to improve guide-wire visualization in low-quality fluoroscopic images and to estimate the position of the guide wire in world coordinates. A two-step procedure is utilized to track the guide wire in subsequent frames. First, a rough estimate of ...

提出了一种在X射线透视下提取和跟踪血管内介入过程中导丝位置的方法。该方法可用于改善低质量透视图像中的导丝可视化，并估计导丝在世界坐标中的位置。采用两步法在后续帧中跟踪导丝。首先，粗略估计...

The aim of the study was to provide mathematical descriptors for the border of pigmented skin lesion images and to assess their efficacy for distinction among different lesion groups. New descriptors such as lesion slope and lesion slope regularity are introduced and mathematically defined. A new algorithm based on the Catmull-Rom spline method and the computation of the gray-level gradient of poi...

该研究旨在为色素性皮肤病变图像的边界提供数学描述符，并评估其在不同病变组别区分中的有效性。引入了新的描述符，如病变斜率和病变斜率规律性，并给出了数学定义。提出了一种基于Catmull-Rom样条方法和灰度梯度计算的新算法...

Many imaging experiments involve acquiring a time series of images. To improve imaging speed, several "data-sharing" methods have been proposed, which collect one (or a few) high-resolution reference(s) and a sequence of reduced data sets. In image reconstruction, two methods, known as "Keyhole" and reduced-encoding imaging by generalized-series reconstruction (RIGR), have been used. Keyhole fills...

许多成像实验涉及获取一系列时间图像。为了提高成像速度，提出了几种“数据共享”方法，这些方法收集一个（或几个）高分辨率参考图像和一系列缩减数据集。在图像重建中，使用了两种方法，即“钥匙孔”和基于广义级数重建的缩减编码成像（RIGR）。钥匙孔填充...

We explore a new paradigm for the analysis of event-related functional magnetic resonance images (fMRI) of brain activity. We regard the fMRI data as a very large set of time series x/sub i/(t), indexed by the position i of a voxel inside the brain. The decision that a voxel i/sub 0/ is activated is based not solely on the value of the fMRI signal at i/sub 0/, but rather on the comparison of all t...

我们探索了一种分析大脑活动的事件相关功能磁共振成像（fMRI）数据的新范式。我们将fMRI数据视为一组非常庞大的时间序列x_i(t)，这些序列由大脑内体素的位置i索引。判断体素i_0是否被激活不仅基于i_0处fMRI信号的值，还依赖于所有t...

A novel single-shot trapezoidal-gradient-based Lissajous trajectory is described and implemented on a 3-tesla magnetic resonance (MR) scanner. A feature of this trajectory is that its sampling points are located on a nonequidistant rectangular grid, which permits the usage of one-dimensional optimal algorithms to increase the robustness and speed of image reconstruction. Another advantage of the t...

描述并实现了一种基于梯形梯度的新型单次激发利萨如轨迹，在3特斯拉磁共振（MR）扫描仪上。该轨迹的一个特点是其采样点位于非等距矩形网格上，这允许使用一维优化算法来提高图像重建的鲁棒性和速度。该轨迹的另一个优势是...