Volume 20, Issue 9

Guidance systems designed for neurosurgery, hip surgery, spine surgery and for approaches to other anatomy that is relatively rigid can use rigid-body transformations to accomplish image registration. These systems often rely on point-based registration to determine the transformation and many such systems use attached fiducial markers to establish accurate fiducial points for the registration, the points being established by some fiducial localization process. Accuracy is important to these systems, as is knowledge of the level of that accuracy. An advantage of marker-based systems, particularly those in which the markers are bone-implanted, is that registration error depends only on the fiducial localization and is, thus, to a large extent independent of the particular object being registered. Thus, it should be possible to predict the clinical accuracy of marker-based systems on the basis of experimental measurements made with phantoms or previous patients. For most registration tasks, the most important error measure is target registration error (TRE), which is the distance after registration between corresponding points not used in calculating the registration transform. Here, the authors derive an approximation to the distribution of TRE; this is an extension of previous work that gave the expected squared value of TRE. They show the distribution of the squared magnitude of TRE and that of the component of TRE in an arbitrary direction. Using numerical simulations, the authors show that their theoretical results are a close match to the simulated ones.

设计用于神经外科、髋关节手术、脊柱手术及其他相对刚性解剖结构入路的导航系统可利用刚体变换实现图像配准。这些系统通常依赖于基于点的配准来确定变换，且许多此类系统使用附着式基准标记来建立用于配准的精确基准点，这些点通过某些基准定位过程确定。准确性对这些系统至关重要，了解准确性的水平也同样重要。基于标记的系统（尤其是标记植入骨内的系统）的一个优点是，配准误差仅取决于基准定位，因此在很大程度上独立于所配准的具体对象。因此，基于标记系统的临床准确性应可通过使用体模或先前患者的实验测量来预测。对于大多数配准任务，最重要的误差指标是目标配准误差（TRE），即配准后未用于计算配准变换的对应点之间的距离。在此，作者推导了TRE分布的近似值；这是先前工作的扩展，先前工作给出了TRE的期望平方值。他们展示了TRE平方幅度以及TRE沿任意方向分量的分布。通过数值模拟，作者表明他们的理论结果与模拟结果紧密吻合。

Presents a system for detecting retinal boundaries in optical coherence tomography (OCT) B-scans. OCT is a relatively new imaging modality giving cross-sectional images that are qualitatively similar to ultrasound. However, the axial resolution with OCT is much higher, on the order of 10 /spl mu/m. Objective, quantitative measures of retinal thickness may be made from OCT images. Knowledge of reti...

介绍了一种在光学相干断层扫描（OCT）B扫描中检测视网膜边界的系统。OCT是一种相对较新的成像模态，可提供与超声定性相似的横截面图像。然而，OCT的轴向分辨率要高得多，大约为10微米。可以从OCT图像中获取视网膜厚度的客观、定量测量值。对视网膜的了解...

This editorial reviews the history and summarizes achievements, describes current activities, indicates future directions, and finally suggests some keys to success of the Biomedical Imaging Resource (BTR) at Mayo Clinic/Foundation. The origin and history section provides a chronological description, with associated references, emphasizing progress and milestones over the past three decades. Sever...

这篇社论回顾了历史并总结了成就，描述了当前的活动，指出了未来的方向，最后提出了一些梅奥诊所/基金会生物医学成像资源（BTR）成功的关键。起源和历史部分提供了按时间顺序的描述，并附有相关参考文献，重点介绍了过去三十年来的进展和里程碑。

This paper presents a procedure for the analysis of left-right (bilateral) asymmetry in mammograms. The procedure is based upon the detection of linear directional components by using a multiresolution representation based upon Gabor wavelets. A particular wavelet scheme with two-dimensional Gabor filters as elementary functions with varying tuning frequency and orientation, specifically designed ...

本文提出了一种分析乳腺X线图像中左右（双侧）不对称性的方法。该方法基于使用Gabor小波的多分辨率表示来检测线性方向分量。一种特定的二维Gabor滤波器作为基本函数的方案，具有变化的调谐频率和方向，专门设计...

It is well understood that the optimal classification decision variable is the likelihood ratio or any monotonic transformation of the likelihood ratio. An automated classifier which maps from an input space to one of the likelihood ratio family of decision variables is an optimal classifier or "ideal observer." Artificial neural networks (ANNs) are frequently used as classifiers for many problems...

众所周知，最优分类决策变量是似然比或似然比的任意单调变换。一种将输入空间映射到似然比族决策变量之一的自动分类器是最优分类器或“理想观察者”。人工神经网络（ANN）经常被用作许多问题的分类器...

A reconstruction technique for breast tissue elasticity modulus is described. This technique assumes that the geometry of normal and suspicious tissues is available from a contrast-enhanced magnetic resonance image. Furthermore, it is assumed that the modulus is constant throughout each tissue volume. The technique, which uses quasi-static strain data, is iterative where each iteration involves mo...

描述了一种用于乳腺组织弹性模量的重建技术。该技术假设正常和可疑组织的几何形状可从对比增强磁共振图像获得。此外，假设模量在每个组织体积内是恒定的。该技术使用准静态应变数据，是迭代的，每次迭代涉及...

Presents two methods developed to extract quantitative information from video recordings of neonatal seizures in the form of temporal motion strength and motor activity signals. Motion strength signals are extracted by measuring the area of the body parts that move during the seizure and the relative speed of motion using a combination of spatiotemporal subband decomposition of video, nonlinear fi...

提出了两种方法，通过时空运动强度信号和运动活动信号的形式，从新生儿癫痫的视频记录中提取定量信息。运动强度信号通过测量癫痫发作期间身体部位移动的面积以及使用视频的时空子带分解、非线性滤波等组合方法提取相对运动速度。

Objective testing of centerline extraction accuracy in quantitative coronary angiography (QCA) algorithms is a very difficult task. Standard tools for this task are not yet available. The authors present a simulation tool that generates synthetic angiographic images of a single coronary artery with predetermined centerline and diameter function. This simulation tool was used creating a library of ...

定量冠状动脉造影（QCA）算法中中心线提取精度的客观测试是一项非常困难的任务。目前尚无标准工具可完成此任务。作者提出了一种模拟工具，可生成具有预定中心线和直径函数的单支冠状动脉合成造影图像。该模拟工具用于创建数据库……

The identification of bronchi on Computed Tomography (CT) images of the lungs provides valuable clinical information in patients with suspected airways diseases including bronchiectasis, emphysema, or constrictive obliterative bronchiolitis. The automated recognition of the airways is, therefore, an important part of a diagnosis aid system for resolving potential ambiguities associated with intens...

在肺部计算机断层扫描（CT）图像上识别支气管，为疑似气道疾病（包括支气管扩张、肺气肿或缩窄性闭塞性细支气管炎）患者提供了有价值的临床信息。因此，气道自动识别是诊断辅助系统的重要组成部分，用于解决与强度相关的潜在歧义...

One of the primary drawbacks in the application of magnetic resonance spectroscopic imaging is the long acquisition times required to obtained the desired resolution. When region of support information is available, the number of phase-encoding steps and thus time can be reduced without loss of information if the k-space locations are chosen well. The authors propose to select locations using a re...

磁共振波谱成像应用的主要缺点之一是获取所需分辨率所需的长时间采集。当支撑区域信息可用时，如果k空间位置选择得当，可以在不丢失信息的情况下减少相位编码步数，从而减少时间。作者提出使用...