Volume 22, Issue 11

Nonrigid registration of medical images is important for a number of applications such as the creation of population averages, atlas-based segmentation, or geometric correction of functional magnetic resonance imaging (IMRI) images to name a few. In recent years, a number of methods have been proposed to solve this problem, one class of which involves maximizing a mutual information (Ml)-based objective function over a regular grid of splines. This approach has produced good results but its computational complexity is proportional to the compliance of the transformation required to register the smallest structures in the image. Here, we propose a method that permits the spatial adaptation of the transformation's compliance. This spatial adaptation allows us to reduce the number of degrees of freedom in the overall transformation, thus speeding up the process and improving its convergence properties. To develop this method, we introduce several novelties: 1) we rely on radially symmetric basis functions rather than B-splines traditionally used to model the deformation field; 2) we propose a metric to identify regions that are poorly registered and over which the transformation needs to be improved; 3) we partition the global registration problem into several smaller ones; and 4) we introduce a new constraint scheme that allows us to produce transformations that are topologically correct. We compare the approach we propose to more traditional ones and show that our new algorithm compares favorably to those in current use.

医学图像的非刚性配准对于许多应用非常重要，例如创建人口平均值、基于图谱的分割或功能磁共振成像（fMRI）图像的几何校正等。近年来，已经提出了许多方法来解决这个问题，其中一类方法涉及在规则的样条网格上最大化基于互信息的目标函数。这种方法取得了良好的结果，但其计算复杂度与配准图像中最细微结构所需的变换的顺应性成正比。在这里，我们提出了一种允许空间自适应变换顺应性的方法。这种空间自适应允许我们减少整体变换的自由度，从而加快过程并改善其收敛特性。为了开发这种方法，我们引入了几个新颖之处：1）我们依赖径向对称基函数，而不是传统用于建模变形场的B样条；2）我们提出了一种度量来识别配准不良且需要改进变换的区域；3）我们将全局配准问题分解为几个小问题；4）我们引入了一种新的约束方案，使我们能够产生拓扑正确的变换。我们将我们提出的方法与更传统的方法进行了比较，并表明我们的新算法优于当前使用的方法。

Motivated by the problem of retinal image registration, this paper introduces and analyzes a new registration algorithm called Dual-Bootstrap Iterative Closest Point (Dual-Bootstrap ICP). The approach is to start from one or more initial, low-order estimates that are only accurate in small image regions, called bootstrap regions. In each bootstrap region, the algorithm iteratively: 1) refines the ...

受视网膜图像配准问题的启发，本文介绍并分析了一种新的配准算法，称为双引导迭代最近点（Dual-Bootstrap ICP）。该方法从一个或多个初始的低阶估计开始，这些估计仅在小图像区域（称为引导区域）内准确。在每个引导区域内，算法迭代地：1) 细化...

We present a gradient-based method for rigid registration of a patient preoperative computed tomography (CT) to its intraoperative situation with a few fluoroscopic X-ray images obtained with a tracked C-arm. The method is noninvasive, anatomy-based, requires simple user interaction, and includes validation. It is generic and easily customizable for a variety of routine clinical uses in orthopaedi...

我们提出了一种基于梯度的刚性配准方法，用于将患者术前计算机断层扫描（CT）与其术中情况（通过跟踪C臂获取的少量荧光透视X光图像）进行配准。该方法具有非侵入性、基于解剖结构、需要简单的用户交互，并包含验证。它具有通用性，易于定制，适用于骨科中的多种常规临床用途。

A crucial part of image-guided therapy is registration of preoperative and intraoperative images, by which the precise position and orientation of the patient's anatomy is determined in three dimensions. This paper presents a novel approach to register three-dimensional (3-D) computed tomography (CT) or magnetic resonance (MR) images to one or more two-dimensional (2-D) X-ray images. The registrat...

图像引导治疗的关键部分是术前和术中图像的配准，通过配准可以确定患者解剖结构的三维精确位置和方向。本文提出了一种新颖的方法，将三维（3-D）计算机断层扫描（CT）或磁共振（MR）图像与一张或多张二维（2-D）X射线图像进行配准。配准...

We propose a new method for aligning three-dimensional (3-D) magnetic resonance angiography (MRA) with 2-D X-ray digital subtraction angiograms (DSA). Our method is developed from our algorithm to register computed tomography volumes to X-ray images based on intensity matching of digitally reconstructed radiographs (DRRs). To make the DSA and DRR more similar, we transform the MRA images to images...

我们提出了一种新方法，用于将三维磁共振血管造影（MRA）与二维X射线数字减影血管造影（DSA）进行对齐。该方法基于我们之前开发的通过数字重建放射影像（DRR）强度匹配来将CT体积与X射线图像配准的算法。为了使DSA和DRR更加相似，我们将MRA图像转换为图像...

We describe a registration and tracking technique to integrate cardiac X-ray images and cardiac magnetic resonance (MR) images acquired from a combined X-ray and MR interventional suite (XMR). Optical tracking is used to determine the transformation matrices relating MR image coordinates and X-ray image coordinates. Calibration of X-ray projection geometry and tracking of the X-ray C-arm and table...

我们描述了一种配准与跟踪技术，用于集成从联合X射线和MR介入套间(XMR)采集的心脏X射线图像和心脏磁共振图像。光学跟踪用于确定MR图像坐标与X射线图像坐标之间的变换矩阵。校准X射线投影几何以及跟踪X射线C臂和床...

Mammogram registration is an important technique to optimize the display of cases on a digital viewing station, and to find corresponding regions in temporal pairs of mammograms for computer-aided diagnosis algorithms. Four methods for mammogram registration were tested and results were compared. The performance of all registration methods was measured by comparing the distance between annotations...

乳腺X线图像配准是一项重要技术，用于优化数字阅片站上病例的显示，并找到计算机辅助诊断算法所需的时间序列乳腺X线图像对中的对应区域。测试了四种乳腺X线图像配准方法，并比较了结果。通过比较注释之间的距离来衡量所有配准方法的性能……

In order to demonstrate the growth of the medical image registration field over the past decades, this paper presents the number of journal publications on this topic since 1988 until 2002. In a similar manner, trends in topics within the field of medical image registration are detected. Publications on computed tomography (CT) and magnetic resonance imaging (MRI) are rather constant through the y...

为了展示过去几十年医学图像配准领域的发展，本文介绍了1988年至2002年间关于该主题的期刊发表数量。类似地，检测了医学图像配准领域内的主题趋势。关于计算机断层扫描（CT）和磁共振成像（MRI）的出版物数量多年来相当稳定...

A freehand scanning protocol is the only way to acquire arbitrary large volumes of three-dimensional ultrasound (US) data. For some applications, multiple freehand sweeps are required to cover the area of interest. Aligning these multiple sweeps is difficult, typically requiring nonrigid image-based registration as well as the readings from the spatial locator attached to the US probe. Conventiona...

自由手扫描协议是获取任意大体积三维超声数据的唯一方法。对于某些应用，需要多次自由手扫描以覆盖感兴趣区域。对齐这些多次扫描是困难的，通常需要基于图像的非刚性配准以及附着在超声探头上的空间定位器的读数。传统上...

A three-dimensional wavelet-based algorithm for nonlinear registration of an elastic body model of the brain is developed. Surfaces of external and internal anatomic brain structures are used to guide alignment. The deformation field is represented with a multiresolution wavelet expansion and is modeled by the partial differential equations of linear elasticity. A progressive estimation of the reg...

提出了一种基于三维小波的弹性体脑模型非线性配准算法。利用脑外部和内部解剖结构的表面引导配准。变形场用多分辨率小波展开表示，并由线性弹性偏微分方程建模。逐步估计配准...

We propose a voxel-based nonrigid registration algorithm for temporal subtraction of two-dimensional thorax X-ray computed radiography images of the same subject. The deformation field is represented by a B-spline with a limited number of degrees of freedom, that allows global rib alignment to minimize subtraction artifacts within the lung field without obliterating interval changes of clinically ...

我们提出了一种基于体素的非刚性配准算法，用于同一受试者二维胸部X射线计算机放射摄影图像的时间减影。变形场由具有有限自由度的B样条表示，允许全局肋骨对齐，以最小化肺野内的减影伪影，同时不消除临床上的间隔变化...

Brain shift during open cranial surgery presents a challenge for maintaining registration with image-guidance systems. Ultrasound (US) is a convenient intraoperative imaging modality that may be a useful tool in detecting tissue shift and updating preoperative images based on intraoperative measurements of brain deformation. We have quantitatively evaluated the ability of spatially tracked freehan...

开颅手术中的脑移位对保持与图像引导系统的配准提出了挑战。超声是一种方便的术中成像方式，可能是一种有用的工具，用于检测组织移位并根据术中脑变形测量更新术前图像。我们定量评估了空间追踪自由手...

Flow-mediated dilation (FMD) offers a mechanism to characterize endothelial function and, therefore, may play a role in the diagnosis of cardiovascular diseases. Computerized analysis techniques are very desirable to give accuracy and objectivity to the measurements. Virtually all methods proposed up to now to measure FMD rely on accurate edge detection of the arterial wall, and they are not alway...

血流介导的扩张（FMD）提供了一种表征内皮功能的机制，因此可能在心血管疾病的诊断中发挥作用。计算机化分析技术非常理想，可以给测量带来准确性和客观性。迄今为止，几乎所有提出的测量FMD的方法都依赖于动脉壁的精确边缘检测，但它们并不总是……

Registration using the least-squares cost function is sensitive to the intensity fluctuations caused by the blood oxygen level dependent (BOLD) signal in functional MRI (fMRI) experiments, resulting in stimulus-correlated motion errors. These errors are severe enough to cause false-positive clusters in the activation maps of datasets acquired from 3T scanners. This paper presents a new approach to...

使用最小二乘代价函数进行配准对功能MRI（fMRI）实验中血氧水平依赖（BOLD）信号引起的强度波动敏感，导致刺激相关的运动误差。这些误差严重到足以在从3T扫描仪获取的数据集的激活图中引起假阳性簇。本文提出了一种新方法……

In many cases the combined assessment of three-dimensional anatomical and functional images [single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT)] is necessary to determine the precise nature and extent of lesions. It is important, prior to performing the addition, subtraction, or any other combinatio...

在许多情况下，需要对三维解剖和功能图像[单光子发射计算机断层扫描（SPECT）、正电子发射断层扫描（PET）、磁共振成像（MRI）和计算机断层扫描（CT）]进行联合评估，以确定病变的精确性质和范围。重要的是，在执行加法、减法或任何其他组合之前...