Volume 24, Issue 10

We propose a new model to simulate the three-dimensional (3-D) growth of glioblastomas multiforma (GBMs), the most aggressive glial tumors. The GBM speed of growth depends on the invaded tissue: faster in white than in gray matter, it is stopped by the dura or the ventricles. These different structures are introduced into the model using an atlas matching technique. The atlas includes both the segmentations of anatomical structures and diffusion information in white matter fibers. We use the finite element method (FEM) to simulate the invasion of the GBM in the brain parenchyma and its mechanical interaction with the invaded structures (mass effect). Depending on the considered tissue, the former effect is modeled with a reaction-diffusion or a Gompertz equation, while the latter is based on a linear elastic brain constitutive equation. In addition, we propose a new coupling equation taking into account the mechanical influence of the tumor cells on the invaded tissues. The tumor growth simulation is assessed by comparing the in-silico GBM growth with the real growth observed on two magnetic resonance images (MRIs) of a patient acquired with 6 mo difference. Results show the feasibility of this new conceptual approach and justifies its further evaluation.

我们提出了一种新模型来模拟多形性胶质母细胞瘤（GBM）的三维生长，这是最具侵袭性的胶质肿瘤。GBM的生长速度取决于被侵袭的组织：在白质中比在灰质中更快，并且被硬脑膜或脑室阻止。我们使用图谱匹配技术将这些不同的结构引入模型中。该图谱包括解剖结构的分割和白质纤维中的扩散信息。我们使用有限元方法来模拟GBM在脑实质中的侵袭及其与被侵袭结构的机械相互作用（占位效应）。根据所考虑的组织，前者用反应-扩散或Gompertz方程建模，而后者基于线性弹性脑本构方程。此外，我们提出了一个新的耦合方程，考虑了肿瘤细胞对被侵袭组织的机械影响。通过将计算机模拟的GBM生长与一名患者间隔6个月的两张磁共振图像上观察到的实际生长进行比较，评估了肿瘤生长模拟。结果表明了这种新概念方法的可行性，并证明了其进一步评估的合理性。

We studied the performance of three-dimensional fluorescence tomography of diffuse media in the presence of heterogeneities. Experimental measurements were acquired using an imaging system consisting of a parallel plate-imaging chamber and a lens coupled charge coupled device camera, which enables conventional planar imaging as well as fluorescence tomography. To simulate increasing levels of back...

我们研究了异质性存在下漫射介质的三维荧光层析成像的性能。实验测量采用由平行板成像室和透镜耦合电荷耦合器件相机组成的成像系统获取，该系统能够进行常规平面成像以及荧光层析成像。为了模拟逐渐增加的反...

Currently, the nonadaptive delay-and-sum (DAS) beamformer is extensively used for ultrasound imaging, despite the fact that it has lower resolution and worse interference suppression capability than the adaptive standard Capon beamformer (SCB) if the steering vector corresponding to the signal of interest (SOI) is accurately known. The main problem which restricts the use of SCB, however, is that ...

目前，非自适应延迟求和（DAS）波束形成器广泛应用于超声成像，尽管如果准确知道感兴趣信号（SOI）对应的导向矢量，其分辨率和干扰抑制能力不如自适应标准Capon波束形成器（SCB）。然而，限制SCB使用的主要问题是...

Optical coherence tomography (OCT) is a novel, high-resolution diagnostic tool that is capable of imaging the arterial wall and plaques. The differentiation between different types of atherosclerotic plaque is based on qualitative differences in gray levels and structural appearance. We hypothesize that a quantitative data analysis of the OCT signal allows measurement of light attenuation by the l...

光学相干断层扫描（OCT）是一种新型的高分辨率诊断工具，能够对动脉壁和斑块进行成像。不同类型动脉粥样硬化斑块的区分基于灰度水平和结构外观的定性差异。我们假设对OCT信号进行定量数据分析可以测量光衰减...

Clustered microcalcifications (MC) in mammograms can be an important early sign of breast cancer in women. Their accurate detection is important in computer-aided detection (CADe). In this paper, we propose the use of a recently developed machine-learning technique - relevance vector machine (RVM) - for detection of MCs in digital mammograms. RVM is based on Bayesian estimation theory, of which a ...

乳腺X线图像中的簇状微钙化（MC）可能是女性乳腺癌的重要早期征兆。其准确检测在计算机辅助检测（CADe）中至关重要。本文提出使用一种最近开发的机器学习技术——相关向量机（RVM）——来检测数字乳腺X线图像中的MC。RVM基于贝叶斯估计理论，其中……

In recent years, diffusion tensor imaging (DTI) has become a popular in vivo diagnostic imaging technique in Radiological sciences. In order for this imaging technique to be more effective, proper image analysis techniques suited for analyzing these high dimensional data need to be developed. In this paper, we present a novel definition of tensor "distance" grounded in concepts from information th...

近年来，弥散张量成像（DTI）已成为放射科学中一种流行的体内诊断成像技术。为了使这种成像技术更加有效，需要开发适合分析这些高维数据的适当图像分析技术。在本文中，我们提出了一种基于信息论概念的张量"距离"的新定义。

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important source of information to aid cancer diagnosis. Nevertheless, due to the multi-temporal nature of the three-dimensional volume data obtained from DCE-MRI, evaluation of the image data is a challenging task and tools are required to support the human expert. We investigate an approach for automatic localization an...

动态对比增强磁共振成像（DCE-MRI）已成为辅助癌症诊断的重要信息来源。然而，由于从DCE-MRI获得的三维体积数据具有多时相性，图像数据的评估是一项具有挑战性的任务，需要工具来支持人类专家。我们研究了一种用于自动定位...

The analysis of the three-dimensional (3-D) structure of tumoral invasion fronts of carcinoma of the uterine cervix is the prerequisite for understanding their architectural-functional relationship. The variation range of the invasion patterns known so far reaches from a smooth tumor-host boundary surface to more diffusely spreading patterns, which all are supposed to have a different prognostic r...

分析宫颈癌肿瘤侵袭前沿的三维结构是理解其结构与功能关系的前提。目前已知的侵袭模式变化范围从光滑的肿瘤-宿主边界表面到更弥散的扩散模式，所有这些都被认为具有不同的预后意义...

Vibro-acoustography (VA) is an imaging technique that uses the dynamic (oscillatory) radiation force of two continuous-wave (CW) ultrasound to image objects at low frequency (within the kHz range). In this technique, the dynamic radiation force is created by means of a confocused transducer emitting two ultrasound beams at slightly-shifted frequencies f/sub 1/ and f/sub 2/=f/sub 1/+/spl Delta/f. I...

振动声学成像（VA）是一种利用两个连续波（CW）超声的动态（振荡）辐射力在低频（kHz范围内）对物体进行成像的技术。在该技术中，动态辐射力通过一个共聚焦换能器产生，该换能器发射两个频率略有偏移的超声波束 f1 和 f2=f1+Δf。

While ultrasound- and magnetic resonance-based elastography techniques have proved to be powerful biomedical imaging tools, most approaches assume isotropic material properties. In this paper, a general framework is developed for tomography-based anisotropic elastography. An anatomically well- motivated piece-wise homogeneous model is proposed to represent a class of biological objects consisting ...

虽然基于超声和磁共振的弹性成像技术已被证明是强大的生物医学成像工具，但大多数方法假设各向同性材料属性。本文提出了一种基于层析成像的各向异性弹性成像的一般框架。提出了一个解剖学上合理的分段均匀模型来表示一类生物对象，包括……

We propose a novel method for voxel-based morphometry (VBM), which we call graphical-model-based morphometric analysis (GAMMA), to identify morphological abnormalities automatically, and to find complex probabilistic associations among voxels in magnetic-resonance images and clinical variables. GAMMA is a fully automatic, nonparametric morphometric-analysis algorithm, with high sensitivity and spe...

我们提出了一种新颖的基于体素的形态测量方法，称为基于图模型的形态测量分析（GAMMA），用于自动识别形态异常，并发现磁共振图像中体素与临床变量之间的复杂概率关联。GAMMA是一种全自动、非参数的形态测量分析算法，具有高灵敏度和特异性。

We describe a new approach to the problem of collimator optimization in nuclear medicine; our methodology is illustrated for the challenging case of gallium-67 imaging. Collimator-design methods based on empirical rules, such as specification of an allowable level of single-septal penetration (SSP) at a fixed energy, are especially inappropriate for radionuclides characterized by an abundance of h...

我们描述了一种解决核医学中准直器优化问题的新方法；我们的方法在具有挑战性的镓-67成像案例中得到了说明。基于经验规则的准直器设计方法，例如在固定能量下规定允许的单隔穿透水平，对于以丰富的高能光子为特征的放射性核素尤其不合适...

Geometric and intensity distortions due to the presence of metallic implants in magnetic resonance imaging impede the full exploitation of this advanced imaging modality. The aim of this study is to provide a method for (a) quantifying and (b)reducing the implant distortions in patient images. Initially, a set of reference images (without distortion) was obtained by imaging a custom-designed three...

磁共振成像中金属植入物导致的几何和强度失真阻碍了这种先进成像技术的充分利用。本研究旨在提供一种方法，用于(a)量化和(b)减少患者图像中的植入物失真。首先，通过成像一个定制设计的三...

This paper investigates an accurate reconstruction method to invert the attenuated Radon transform in nonparallel beam (NPB) geometries. The reconstruction method contains three major steps: 1) performing one-dimensional phase-shift rebinning; 2) implementing nonuniform Hilbert transform; and 3) applying Novikov's explicit inversion formula. The method seems to be adaptive to different settings of...

本文研究了一种精确的重建方法，用于反演非平行束（NPB）几何中的衰减拉东变换。该方法包含三个主要步骤：1）执行一维相移重排；2）实现非均匀希尔伯特变换；3）应用诺维科夫显式反演公式。该方法似乎适用于不同的设置...

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