Volume 19, Issue 11

The problem of providing surgical navigation using image overlays on the operative scene can be split into four main tasks-calibration of the optical system; registration of preoperative images to the patient; system and patient tracking, and display using a suitable visualization scheme. To achieve a convincing result in the magnified microscope view a very high alignment accuracy is required. The authors have simulated an entire image overlay system to establish the most significant sources of error and improved each of the stages involved. The microscope calibration process has been automated. The authors have introduced bone-implanted markers for registration and incorporated a locking acrylic dental stent (LADS) for patient tracking. The LADS can also provide a less-invasive registration device with mean target error of 0.7 mm in volunteer experiments. These improvements have significantly increased the alignment accuracy of the authors' overlays. Phantom accuracy is 0.3-0.5 mm and clinical overlay errors were 0.5-1.0 mm on the bone fiducials and 0.5-4 mm on target structures. The authors have improved the graphical representation of the stereo overlays. The resulting system provides three-dimensional surgical navigation for microscope-issisted guided interventions (MAGI).

通过图像叠加在手术场景上提供手术导航的问题可以分为四个主要任务：光学系统的校准；术前图像与患者的配准；系统和患者的跟踪；以及使用合适的可视化方案进行显示。为了在放大的显微镜视野中获得令人信服的结果，需要非常高的对准精度。作者模拟了整个图像叠加系统，以确定最主要的误差来源，并改进了所涉及的每个阶段。显微镜校准过程已实现自动化。作者引入了骨植入标记物进行配准，并采用了可锁定的丙烯酸牙科支架（LADS）进行患者跟踪。在志愿者实验中，LADS还可以作为一种侵入性较小的配准装置，平均目标误差为0.7毫米。这些改进显著提高了作者叠加图像的对准精度。体模精度为0.3-0.5毫米，临床叠加误差在骨基准点上为0.5-1.0毫米，在目标结构上为0.5-4毫米。作者改进了立体叠加的图形表示。最终系统为显微镜辅助引导干预（MAGI）提供了三维手术导航。

Presents a dual-energy (DE) transmission computed tomography (CT) reconstruction method. It is statistically motivated and features nonnegativity constraints in the density domain. A penalized weighted least squares (PWLS) objective function has been chosen to handle the non-Poisson noise added by amorphous silicon (aSi:H) detectors. A Gauss-Seidel algorithm has been used to minimize the objective...

提出了一种双能量（DE）透射计算机断层扫描（CT）重建方法。该方法基于统计原理，具有密度域非负约束的特点。选择惩罚加权最小二乘（PWLS）目标函数来处理非晶硅（aSi:H）探测器引入的非泊松噪声。采用高斯-赛德尔算法来最小化目标函数...

Mapping of functional magnetic resonance imaging (fMRI) to conventional anatomical MRI is a valuable step in the interpretation of fMRI activations. One of the main limits on the accuracy of this alignment arises from differences in the geometric distortion induced by magnetic field inhomogeneity. This paper describes an approach to the registration of echo planar image (EPI) data to conventional ...

将功能磁共振成像（fMRI）映射到常规解剖MRI是解释fMRI激活的重要步骤。这种配准准确性的主要限制之一是由磁场不均匀性引起的几何畸变差异。本文描述了一种将回波平面成像（EPI）数据配准到常规...的方法。

This paper presents a generalized statistical texture analysis technique for characterizing and recognizing typical, diagnostically most important, vascular patterns relating to cervical lesions from colposcopic images. The contributions of the research include: (1) the introduction of a generalized texture analysis technique based on the combination of the conventional statistical and structural ...

本文提出了一种广义统计纹理分析技术，用于从阴道镜图像中表征和识别与宫颈病变相关的典型、诊断上最重要的血管模式。该研究的贡献包括：（1）引入了基于传统统计和结构相结合的广义纹理分析技术...

From a set of longitudinal three-dimensional scans of the same anatomical structure, the authors have accurately modeled the temporal shape and size changes using a linear shape model. On a total of 31 computed tomography scans of the mandible from six patients, 14,851 semilandmarks are found automatically using shape features and a new algorithm called geometry-constrained diffusion. The semiland...

作者利用一组同一解剖结构的纵向三维扫描，通过线性形状模型精确模拟了时间上的形状和大小变化。基于六名患者的31次下颌骨CT扫描，使用形状特征和一种名为几何约束扩散的新算法自动找到了14851个半地标。半地标...

The ability to estimate a surface from a set of cross sections allows calculation of the enclosed volume and the display of the surface in three-dimensions. This process has increasingly been used to derive useful information from medical data. However, extracting the cross sections (segmenting) can be very difficult, and automatic segmentation methods are not sufficiently robust to handle all sit...

从一组截面估计表面的能力使得可以计算包围的体积并在三维中显示表面。这一过程越来越多地被用于从医学数据中提取有用信息。然而，提取截面（分割）可能非常困难，且自动分割方法不够鲁棒，无法处理所有情况...

A radial search technique is presented for detecting skin tumor borders in clinical dermatology images. First, it includes two rounds of radial search based on the same tumor center. The first-round search is independent, and the second-round search is knowledge-based tracking. Then a rescan with a new center is used to solve the blind-spot problem. The algorithm is tested on model images with exc...

提出了一种用于临床皮肤科图像中皮肤肿瘤边界检测的径向搜索技术。首先，该方法包括基于同一肿瘤中心的两轮径向搜索。第一轮搜索是独立的，第二轮搜索是基于知识跟踪的。然后，使用新中心进行重新扫描以解决盲点问题。该算法在模型图像上进行了测试...

A regularized color clustering algorithm is proposed to solve the color clustering problem in medical image database. By incorporating both measures of cluster separability and cluster compactness, regularized color clustering allows the automatic extraction of significant color groups with varying populations. Experimental results in different color spaces show that the regularized color clusteri...

提出了一种正则化颜色聚类算法来解决医学图像数据库中的颜色聚类问题。通过同时考虑聚类分离度和聚类紧致度，正则化颜色聚类能够自动提取具有不同种群数量的重要颜色组。在不同颜色空间中的实验结果表明，正则化颜色聚类...

In many transmission imaging geometries, the transmitted "beams" of photons overlap on the detector, such that a detector element may record photons that originated in different sources or source locations and thus traversed different paths through the object. Examples include systems based on scanning line sources or on multiple parallel rod sources. The overlap of these beams has been disregarde...

在许多透射成像几何中，传输的“光束”在探测器上重叠，使得一个探测器元件可能记录来自不同源或源位置、从而穿过物体不同路径的光子。例子包括基于扫描线源或多平行棒源的系统。这些光束的重叠被忽略...

A common challenge for automated segmentation techniques is differentiation between images of close objects that have similar intensities, whose boundaries are often blurred due to partial-volume effects. The authors propose a novel approach to segmentation of two-dimensional images, which addresses this challenge. Their method, which they call intrinsic shape for segmentation (ISeg), analyzes iso...

自动分割技术的一个常见挑战是区分具有相似强度的邻近物体图像，这些物体的边界常常因部分容积效应而模糊。作者提出了一种新的二维图像分割方法，称为内在形状分割（ISeg），通过分析等高线图来解决这一挑战。