Volume 28, Issue 2

We propose an integral concept for tractography to describe crossing and splitting fibre bundles based on the fibre orientation distribution function (ODF) estimated from high angular resolution diffusion imaging (HARDI). We show that in order to perform accurate probabilistic tractography, one needs to use a fibre ODF estimation and not the diffusion ODF. We use a new fibre ODF estimation obtained from a sharpening deconvolution transform (SDT) of the diffusion ODF reconstructed from q -ball imaging (QBI). This SDT provides new insight into the relationship between the HARDI signal, the diffusion ODF, and the fibre ODF. We demonstrate that the SDT agrees with classical spherical deconvolution and improves the angular resolution of QBI. Another important contribution of this paper is the development of new deterministic and new probabilistic tractography algorithms using the full multidirectional information obtained through use of the fibre ODF. An extensive comparison study is performed on human brain datasets comparing our new deterministic and probabilistic tracking algorithms in complex fibre crossing regions. Finally, as an application of our new probabilistic tracking, we quantify the reconstruction of transcallosal fibres intersecting with the corona radiata and the superior longitudinal fasciculus in a group of eight subjects. Most current diffusion tensor imaging (DTI)-based methods neglect these fibres, which might lead to incorrect interpretations of brain functions.

我们提出了一种用于描述基于高角分辨率扩散成像（HARDI）估计的纤维取向分布函数（ODF）的交叉和分裂纤维束的追踪综合概念。我们展示了为了进行准确的概率性纤维追踪，需要使用纤维ODF估计而不是扩散ODF。我们使用了从q-ball成像（QBI）重建的扩散ODF的锐化反卷积变换（SDT）获得的新纤维ODF估计。这种SDT提供了对HARDI信号、扩散ODF和纤维ODF之间关系的新见解。我们证明SDT与经典球面反卷积一致，并提高了QBI的角分辨率。本文的另一个重要贡献是利用通过纤维ODF获得的全多方向信息，开发了新的确定性和新的概率性纤维追踪算法。在人类脑数据集上进行了广泛的比较研究，比较了我们在复杂纤维交叉区域的新确定性和概率性追踪算法。最后，作为我们新的概率性追踪的应用，我们在八名受试者中量化了与放射冠和上纵束相交的跨胼胝体纤维的重建。目前大多数基于扩散张量成像（DTI）的方法忽略了这些纤维，这可能导致对脑功能的错误解释。

Metal implants such as hip prostheses and dental fillings produce streak and star artifacts in the reconstructed computed tomography (CT) images. Due to these artifacts, the CT image may not be diagnostically usable. A new reconstruction procedure is proposed that reduces the streak artifacts and that might improve the diagnostic value of the CT images. The procedure starts with a maximum a poster...

金属植入物如髋关节假体和牙科填充物会在重建的计算机断层扫描（CT）图像中产生条纹和星状伪影。由于这些伪影，CT图像可能无法用于诊断。提出了一种新的重建过程，可减少条纹伪影，并可能提高CT图像的诊断价值。该过程从最大后验开始...

The goal of this work is to perform a segmentation of the intimamedia thickness (IMT) of carotid arteries in view of computing various dynamical properties of that tissue, such as the elasticity distribution (elastogram). The echogenicity of a region of interest comprising the intima-media layers, the lumen, and the adventitia in an ultrasonic B-mode image is modeled by a mixture of three Nakagami...

本工作的目的是对颈动脉内中膜厚度（IMT）进行分割，以计算该组织的各种动态特性，例如弹性分布（弹性图）。超声B模式图像中感兴趣区域（包括内中膜层、管腔和外膜）的回声性由三个Nakagami分布的混合模型建模...

Postacquisition denoising of magnetic resonance (MR) images is of importance for clinical diagnosis and computerized analysis, such as tissue classification and segmentation. It has been shown that the noise in MR magnitude images follows a Rician distribution, which is signal-dependent when signal-to-noise ratio (SNR) is low. It is particularly difficult to remove the random fluctuations and bias...

磁共振（MR）图像的后采集去噪对于临床诊断和计算机化分析（如组织分类和分割）非常重要。研究表明，MR幅度图像中的噪声服从Rician分布，当信噪比（SNR）较低时，该分布是信号依赖的。去除随机波动和偏差尤其困难...

The human lungs are divided into five distinct anatomic compartments called the lobes, which are separated by the pulmonary fissures. The accurate identification of the fissures is of increasing importance in the early detection of pathologies, and in the regional functional analysis of the lungs. We have developed an automatic method for the segmentation and analysis of the fissures, based on the...

人类肺部分为五个不同的解剖隔室，称为肺叶，由肺裂分隔。准确识别肺裂在病理早期检测和肺部区域功能分析中日益重要。我们开发了一种基于...的自动方法用于肺裂的分割和分析。

This work presents an iterative expectation-maximization (EM) approach to the maximum a posteriori (MAP) solution of segmenting tissue mixtures inside each image voxel. Each tissue type is assumed to follow a normal distribution across the field-of-view (FOV). Furthermore, all tissue types are assumed to be independent from each other. Under these assumptions, the summation of all tissue mixtures ...

本文提出了一种迭代期望最大化（EM）方法，用于求解每个图像体素内分割组织混合物的最大后验（MAP）解。假设每个组织类型在视场（FOV）内服从正态分布。此外，所有组织类型相互独立。在这些假设下，所有组织混合物的总和...

A novel approach is proposed for quantitatively characterizing the spatial patterns of activation statistics in functional magnetic resonance imaging (fMRI) activation maps. Specifically, we propose using 3-D invariant moment descriptors, as opposed to the traditionally-employed magnitude-based features such as mean voxel statistics or percentage of activated voxels, to characterize the task-speci...

提出了一种新方法，用于定量表征功能磁共振成像（fMRI）激活图中激活统计的空间模式。具体而言，我们建议使用三维不变矩描述符，而不是传统采用的基于幅度的特征（如平均体素统计量或激活体素百分比），来表征任务特异性的激活模式。

The decomposition of magnetic resonance imaging (MRI) data to generate water and fat images has several applications in medical imaging, including fat suppression and quantification of visceral fat. We introduce a novel algorithm to overcome some of the problems associated with current analytical and iterative decomposition schemes. In contrast to traditional analytical schemes, our approach is ge...

磁共振成像（MRI）数据分解生成水和脂肪图像在医学成像中有多种应用，包括脂肪抑制和内脏脂肪量化。我们引入了一种新颖的算法来克服当前分析和迭代分解方案相关的一些问题。与传统的分析方案相比，我们的方法是...

The use of microarray expression data in state-of-the-art biology has been well established. The widespread adoption of this technology, coupled with the significant volume of data generated per experiment, in the form of images, has led to significant challenges in storage and query retrieval. In this paper, we present a lossless bitplane-based method for efficient compression of microarray image...

在现代生物学中，微阵列表达数据的应用已得到充分证实。该技术的广泛采用，加上每次实验以图像形式产生的大量数据，给存储和查询检索带来了重大挑战。在本文中，我们提出了一种基于无损位平面的方法，用于高效压缩微阵列图像...

We describe a matched subspace detection algorithm to assist in the detection of small tumors in dynamic positron emission tomography (PET) images. The algorithm is designed to differentiate tumors from background using the time activity curves (TACs) that characterize the uptake of PET tracers. TACs are modeled using linear subspaces with additive Gaussian noise. Using TACs from a primary tumor r...

我们描述了一种匹配子空间检测算法，用于辅助动态正电子发射断层扫描（PET）图像中小肿瘤的检测。该算法旨在通过表征PET示踪剂摄取的时间活动曲线（TAC）来区分肿瘤与背景。TAC使用具有加性高斯噪声的线性子空间建模。利用原发肿瘤的TAC...

We propose a new model-based algorithm for the automated tracking of vascular networks in 2-D digital subtraction angiograms. Consecutive scanline profiles are fitted by a parametric imaging model to estimate local vessel center point, radius, edge locations and direction. An adaptive tracking strategy is applied with appropriate termination criteria to track each vessel segment. When tracking sto...

我们提出了一种新的基于模型的算法，用于自动跟踪二维数字减影血管造影图像中的血管网络。通过参数化成像模型拟合连续的扫描线轮廓，以估计局部血管中心点、半径、边缘位置和方向。采用自适应跟踪策略并设置适当的终止准则来跟踪每个血管段。当跟踪停止时...

Functional magnetic resonance imaging (fMRI) data that are corrupted by temporally colored noise are generally preprocessed (i.e., prewhitened or precolored) prior to functional activation detection. In this paper, we propose likelihood-based hypothesis tests that account for colored noise directly within the framework of functional activation detection. Three likelihood-based tests are proposed: ...

功能磁共振成像（fMRI）数据通常受到时间有色噪声的干扰，在进行功能激活检测之前，一般会进行预处理（即预白化或预着色）。在本文中，我们提出了基于似然比的假设检验，该检验直接在功能激活检测框架内考虑有色噪声。提出了三种基于似然比的检验方法：...

In order to describe multiclass classification performance, several figures of merit (FOM) have been proposed. Among the earliest and most widely known of these is the three-class Hotelling trace (3-HT). The goal of this paper is to present theoretical and empirical data demonstrating the failure of 3-HT as a measure of three-class task performance. To help do this, we contrast it to a newly propo...

为了描述多类分类性能，已经提出了几种性能指标（FOM）。其中最早且最广为人知的是三阶Hotelling迹（3-HT）。本文旨在通过理论和实验数据证明3-HT作为三阶任务性能度量的失效。为帮助说明这一点，我们将其与新提出的...

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