Volume 22, Issue 1

We have implemented and validated an algorithm for three-dimensional positron emission tomography transmission-to-computed tomography registration in the chest, using mutual information as a similarity criterion. Inherent differences in the two imaging protocols produce significant nonrigid motion between the two acquisitions. A rigid body deformation combined with localized cubic B-splines is used to capture this motion. The deformation is defined on a regular grid and is parameterized by potentially several thousand coefficients. Together with a spline-based continuous representation of images and Parzen histogram estimates, our deformation model allows closed-form expressions for the criterion and its gradient. A limited-memory quasi-Newton optimization algorithm is used in a hierarchical multiresolution framework to automatically align the images. To characterize the performance of the method, 27 scans from patients involved in routine lung cancer staging were used in a validation study. The registrations were assessed visually by two expert observers in specific anatomic locations using a split window validation technique. The visually reported errors are in the 0- to 6-mm range and the average computation time is 100 min on a moderate-performance workstation.

我们实现并验证了一种用于胸部三维正电子发射断层扫描传输到计算机断层扫描配准的算法，使用互信息作为相似性准则。两种成像协议固有的差异导致两次采集之间存在显著的非刚性运动。采用刚性变形结合局部三次B样条来捕捉这种运动。变形定义在规则网格上，并由可能数千个系数参数化。结合基于样条的图像连续表示和Parzen直方图估计，我们的变形模型允许准则及其梯度的闭式表达式。在分层多分辨率框架中使用有限记忆拟牛顿优化算法自动对齐图像。为了表征该方法的性能，在验证研究中使用了来自常规肺癌分期患者的27次扫描。两位专家观察者使用分割窗口验证技术在特定解剖位置对配准进行视觉评估。视觉报告的误差在0至6毫米范围内，在中档性能工作站上的平均计算时间为100分钟。

Accurate brain tissue segmentation by intensity-based voxel classification of magnetic resonance (MR) images is complicated by partial volume (PV) voxels that contain a mixture of two or more tissue types. In this paper, we present a statistical framework for PV segmentation that encompasses and extends existing techniques. We start from a commonly used parametric statistical image model in which ...

基于磁共振（MR）图像强度的体素分类进行精确的脑组织分割，由于部分容积（PV）体素包含两种或多种组织类型的混合而变得复杂。在本文中，我们提出了一种用于PV分割的统计框架，该框架包含并扩展了现有技术。我们从常用的参数统计图像模型开始...

Recent studies have shown that the surface of the brain is deformed by up to 20 mm after the skull is opened during neurosurgery, which could lead to substantial error in commercial image-guided surgery systems. We quantitatively analyze the intraoperative brain deformation of 24 subjects to investigate whether simple rules can describe or predict the deformation. Interventional magnetic resonance...

近期研究表明，神经外科手术中打开颅骨后，脑表面可变形多达20毫米，这可能导致商业图像引导手术系统出现重大误差。我们定量分析了24名受试者的术中脑变形，以探究简单规则能否描述或预测变形。介入磁共振...

We present a method of constructing a database of intraoperatively observed human subcortical electrophysiology. In this approach, patient electrophysiological data are standardized using a multiparameter coding system, annotated to their respective magnetic resonance images (MRIs), and nonlinearly registered to a high-resolution MRI reference brain. Once registered, we are able to demonstrate clu...

我们提出了一种构建术中观察到的皮层下人体电生理学数据库的方法。该方法采用多参数编码系统对患者电生理数据进行标准化，标注到各自的磁共振图像（MRI）上，并通过非线性配准到高分辨率MRI参考脑。一旦配准，我们能够展示集群...

Locally adaptive image binarization with a sliding-window threshold can be an effective tool for various image processing tasks. We have used the method for the detection of bone ridges in radiotherapy portal images. However, a straight-forward implementation of sliding-window processing is too time consuming for routine use. Therefore, we have developed a new thresholding criterion suitable for i...

局部自适应图像二值化使用滑动窗口阈值可以有效地处理各种图像处理任务。我们已将该方法用于放疗门户图像中骨脊的检测。然而，滑动窗口处理的直接实现对于常规使用来说过于耗时。因此，我们开发了一种新的阈值化准则，适用于...

The period of the Medical Image Display and Analysis Group (MIDAG) so far is 1974-2002: more than 27 years. We began with a focus on two-dimensional (2-D) display: contrast enhancement, display scale choice, and display device standardization. We co-invented adaptive histogram equalization and later improved it to contrast-limited AHE, and we were perhaps the first to show that adaptive contrast e...

到目前为止，医学图像显示与分析小组（MIDAG）的时期是1974年至2002年：超过27年。我们最初专注于二维显示：对比度增强、显示尺度选择和显示设备标准化。我们共同发明了自适应直方图均衡化，后来改进为对比度受限的自适应直方图均衡化，并且我们可能是第一个展示自适应对比度增强的...

Presents a new spectral signature detection approach to magnetic resonance (MR) image classification. It is called constrained energy minimization (CEM) method, which is derived from the minimum variance distortionless response in passive sensor array processing. It considers a bank of spectral channels as an array of sensors where each spectral channel represents a sensor and object spectral sign...

提出了一种新的光谱特征检测方法用于磁共振图像分类。该方法称为约束能量最小化（CEM）方法，源自被动传感器阵列处理中的最小方差无失真响应。它将一组光谱通道视为一个传感器阵列，其中每个光谱通道代表一个传感器，目标光谱特征...

For patient setup verification in external beam radiotherapy (EBRT) of prostate cancer, we developed an information theoretic registration framework, called the minimax entropy registration framework, to simultaneously and iteratively segment portal images and register them to three-dimensional (3-D) computed tomography (CT) image data. The registration framework has two steps, the max step and th...

为了在前列腺癌的外束放疗中验证患者摆位，我们开发了一种信息论配准框架，称为极小极大熵配准框架，以同时并迭代地分割门控图像并将其配准到三维计算机断层扫描(CT)图像数据。该配准框架有两个步骤，最大步和最小步。

Monitoring of cerebral diseases associated with a change of morphology (e.g., stroke) requires unprecedented accuracy for quantification of its morphological progression for each voxel. The purpose of this paper is to provide a technique [voxel-guided morphometry (VGM)] to quantify macroscopic anatomical differences. VGM consists of four steps: 1) coarse linear alignment by the extended principle ...

监测与形态变化相关的脑部疾病（如卒中）需要前所未有的准确性来量化每个体素的形态进展。本文旨在提供一种技术（体素引导的形态测量学，VGM）来量化宏观解剖差异。VGM包括四个步骤：1）通过扩展原理进行粗线性对齐...

Although distributed models are generally accepted as being more realistic than compartment models, use of simpler compartment models is pervasive in nuclear medicine applications, particularly in positron emission tomography (PET). Here, we report on comparisons made between distributed and compartment model outputs to address the question of whether differences between them are sufficient to jus...

尽管分布式模型通常被认为比房室模型更真实，但在核医学应用中，特别是在正电子发射断层扫描（PET）中，使用更简单的房室模型非常普遍。在此，我们报告了分布式模型和房室模型输出之间的比较，以解决它们之间的差异是否足以证明...的问题。

Magnetic resonance (MR) imaging has faced a dramatic increase in real-time capabilities over the last years. However, the application of fast pulse sequences still suffers from low signal-to-noise ratios (SNRs), which can be the limiting factor for the actual acquisition speed. In MR fluoroscopy, filtering along the time and/or spatial domain can be applied to increase the image quality. In this p...

磁共振（MR）成像在过去几年中经历了实时能力的显著提升。然而，快速脉冲序列的应用仍然受到低信噪比（SNR）的影响，这可能是实际采集速度的限制因素。在MR透视中，可以沿时间和/或空间域进行滤波以提高图像质量。在这篇...