Volume 17, Issue 1

A novel approach to correcting for intensity nonuniformity in magnetic resonance (MR) data is described that achieves high performance without requiring a model of the tissue classes present. The method has the advantage that it can be applied at an early stage in an automated data analysis, before a tissue model is available. Described as nonparametric nonuniform intensity normalization (N3), the method is independent of pulse sequence and insensitive to pathological data that might otherwise violate model assumptions. To eliminate the dependence of the field estimate on anatomy, an iterative approach is employed to estimate both the multiplicative bias field and the distribution of the true tissue intensities. The performance of this method is evaluated using both real and simulated MR data.

描述了一种用于校正磁共振（MR）数据中强度不均匀性的新方法，该方法无需组织类别模型即可实现高性能。其优势在于可在自动数据分析的早期阶段、在获得组织模型之前应用。该方法被称为非参数非均匀强度归一化（N3），...

A robust fully automatic method for segmenting the brain from head magnetic resonance (MR) images has been developed, which works even in the presence of radio frequency (RF) inhomogeneities. It has been successful in segmenting the brain in every slice from head images acquired from several different MRI scanners, using different-resolution images and different echo sequences. The method uses an ...

一种鲁棒的全自动方法已经被开发用于从头部磁共振（MR）图像中分割脑部，该方法甚至在存在射频（RF）不均匀性的情况下也能工作。它已成功地从使用不同分辨率的图像和不同回波序列的多个不同MRI扫描仪获取的头部图像的每个切片中分割出脑部。该方法使用一种……

The authors present a new algorithm for identifying the distribution of different material types in volumetric datasets such as those produced with magnetic resonance imaging (MRI) or computed tomography (CT). Because the authors allow for mixtures of materials and treat voxels as regions, their technique reduces errors that other classification techniques can create along boundaries between mater...

作者提出了一种新算法，用于识别体积数据集中不同材料类型的分布，例如通过磁共振成像（MRI）或计算机断层扫描（CT）产生的数据。由于作者允许材料混合并将体素视为区域，他们的技术减少了其他分类技术在材料边界处可能产生的错误...

The authors analyzed the noise characteristics of two-dimensional (2-D) and three-dimensional (3-D) images obtained from the GE Advance positron emission tomography (PET) scanner. Three phantoms were used: a uniform 20-cm phantom, a 3-D Hoffman brain phantom, and a chest phantom with heart and lung inserts. Using gated acquisition, the authors acquired 20 statistically equivalent scans of each pha...

作者分析了从GE Advance正电子发射断层扫描（PET）扫描仪获得的二维（2-D）和三维（3-D）图像的噪声特性。使用了三个体模：一个均匀的20厘米体模，一个3-D Hoffman脑体模，以及一个带有心脏和肺部插入物的胸部体模。使用门控采集，作者获得了每个相位的20个统计上等效的扫描...

This paper describes the usefulness of computer assistance in the acquisition of "good" images for stenosis diagnosis and quantification in coronary angiography. The system recommends the optimal viewpoints from which stenotic lesions can be observed clearly based on images obtained from initial viewpoints. First, the viewpoint dependency of the apparent severity of a stenotic lesion is experiment...

本文描述了计算机辅助在冠状动脉造影中获取用于狭窄诊断和量化的“良好”图像方面的实用性。该系统根据从初始视点获取的图像，推荐能够清晰观察狭窄病变的最佳视点。首先，通过实验研究了狭窄病变表观严重程度的视点依赖性...

Presents a computerized method for automated detection of the boundary of the os calcis on in vivo ultrasound parametric images, using an active dynamic contour model. The initial contour, defined without user interaction, is an iso-contour extracted from the textural feature space. The contour is deformed through the action of internal and external forces, until stability is reached. The external...

提出了一种计算机化方法，用于在体内超声参数图像上自动检测跟骨边界，该方法采用主动动态轮廓模型。初始轮廓无需用户交互，从纹理特征空间中提取等值线。通过内部和外部力的作用使轮廓变形，直至达到稳定。外部力基于图像梯度等。

The spatially varying geometric response of the collimator-detector system in single photon emission computed tomography (SPECT) causes loss in resolution, shape distortions, reconstructed density nonuniformity, and quantitative inaccuracies. A projection space image reconstruction algorithm is used to correct these reconstruction artifacts. The projectors F use strip functions to calculate pixels...

单光子发射计算机断层扫描（SPECT）中准直器-探测器系统的空间变化几何响应会导致分辨率损失、形状畸变、重建密度不均匀以及定量不准确。采用投影空间图像重建算法来纠正这些重建伪影。投影器F使用条带函数计算像素...

This paper deals with the development of standards in the field of medical imaging and picture archiving and communication systems (PACS's), and notably concerning the interworking between PACS's and hospital information systems (HIS). It explains, in detail, how a conceptual model of the management of medical images, such as the medical image management in an open system architecture (MIMOSA) mod...

本文论述了医学影像和图像存档与通信系统（PACS）领域标准的发展，特别是关于PACS与医院信息系统（HIS）之间的互操作。它详细解释了如何构建一个医学图像管理的概念模型，例如开放系统架构中的医学图像管理（MIMOSA）模型……

Optimal filters for the detection of coronary arteries with a diameter range of 0.5-6.0 mm in digital X-ray images are derived using a computational approach. This approach is based on the two requirements for optimal detection. First, the filter should maximize the number of detected true edges and minimize the number of detected false edges. Second, if an edge has been detected, its position sho...

本文通过计算方法推导了用于在数字X射线图像中检测直径范围为0.5-6.0毫米的冠状动脉的最优滤波器。该方法基于最优检测的两个要求。首先，滤波器应最大化检测到的真实边缘数量并最小化检测到的虚假边缘数量。其次，如果检测到边缘，其位置应...

An efficient new method, termed as the cross-reference weighted least square estimate (WLSE) [CRWLSE], is proposed to integrate the incomplete local smoothness information to improve the reconstruction of positron emission tomography (PET) images in the presence of accidental coincidence events and attenuation. The algebraic reconstruction technique (ART) is applied to this new estimate and the co...

提出了一种新的高效方法，称为交叉参考加权最小二乘估计（CRWLSE），用于在存在偶然符合事件和衰减的情况下，整合不完全的局部平滑信息以改善正电子发射断层成像（PET）图像的重建。代数重建技术（ART）应用于这一新估计，并...

Maximum likelihood (ML) methods are widely used in acoustic parameter estimation. Although ML methods are often unbiased, the variance is unacceptably large for many applications, including medical imaging. For such cases, Bayesian estimators can reduce variance and preserve contrast at the cost of an increased bias. Consequently, including prior knowledge about object and noise properties in the ...

最大似然（ML）方法广泛用于声学参数估计。尽管ML方法通常是无偏的，但其方差在许多应用中（包括医学成像）大到无法接受。对于这种情况，贝叶斯估计器可以减小方差并以增加偏差为代价保持对比度。因此，在参数估计中包含关于目标和噪声特性的先验知识...