Popular Articles

Recently, foundations rooted in physics have been laid down for the goal of simulating the propagation of a guide wire inside the vasculature. At the heart of the simulation lies the fundamental task of energy minimization. The energy comes from interaction with the vessel wall and the bending of the guide wire. For the simulation to be useful in actual training, obtaining the smallest possible op...

最近，为了模拟导丝在血管内的传播这一目标，已经奠定了基于物理学的基础。模拟的核心是能量最小化这一基本任务。能量来自与血管壁的相互作用以及导丝的弯曲。为了使模拟在实际训练中有用，需要获得尽可能小的操作...

High-resolution single-photon emission computed tomography (SPECT) imaging in small animals tends to use long imaging times and large injected doses due to the poor sensitivity of single pinhole gamma cameras. To increase sensitivity while maintaining spatial resolution, we designed and constructed a multi-pinhole collimator array to replace the parallel hole collimators of a Ceraspect human SPECT...

由于单针孔伽马相机的灵敏度较低，小动物高分辨率单光子发射计算机断层扫描（SPECT）成像往往需要较长的成像时间和较大的注射剂量。为了在保持空间分辨率的同时提高灵敏度，我们设计并构建了一个多针孔准直器阵列，以替代Ceraspect人体SPECT的平行孔准直器...

A new postprocessing algorithm was developed for the diagnosis of breast cancer using electrical impedance scanning. This algorithm automatically recognizes bright focal spots in the conductivity map of the breast. Moreover, this algorithm discriminates between malignant and benign/normal tissues using two main predictors: phase at 5 kHz and crossover frequency, the frequency at which the imaginar...

开发了一种新的后处理算法，用于使用电阻抗扫描进行乳腺癌诊断。该算法自动识别乳房电导率图中的明亮焦点斑。此外，该算法使用两个主要预测因子区分恶性组织和良性/正常组织：5 kHz时的相位和交叉频率，即虚部消失的频率...

A highly automated method for the identification and quantization of maximum blood velocity curves from Doppler ultrasound flow diagrams is presented. The method uses an image processing scheme to analyze video-recorded image sequences of flow diagrams. The sequences are acquired, a sequence of images relating to chronological cardiac cycles is extracted, and a maximum blood velocity envelope is d...

提出了一种高度自动化的方法，用于从多普勒超声血流图中识别和量化最大血流速度曲线。该方法采用图像处理方案分析视频记录的流图图像序列。获取序列后，提取与时间心搏周期相关的图像序列，并确定最大血流速度包络...

In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpne...

在眼底摄影中，精细对焦是一项要求高且常常因对焦不准导致图像质量不佳的任务。数码相机的引入为实现自动对焦提供了机会。我们开发了一种能够识别最佳对焦的软件算法。自动对焦方法基于我们开发的评估图像锐度的算法……

It is argued that positron annihilation into three photons, although quite rare, could still be used as a new imaging modality of positron emission tomography. The information gained when the three decay photons are detected is significantly higher than in the case of 511 keV two-gamma annihilation. The performance of three-gamma imaging in terms of the required detector properties, spatial resolu...

有人认为，正电子湮灭成三个光子虽然相当罕见，但仍可被用作正电子发射断层扫描的一种新的成像模式。当检测到三个衰变光子时，获得的信息明显高于511 keV双伽马湮灭的情况。三伽马成像在所需探测器特性、空间分辨率等方面的性能...

A dye-edge tracking algorithm was used to determine the corresponding points in the two images (anterior-posterior and lateral) of the digital subtraction biplane angiography. This correspondence was used to reconstruct three-dimensional images of cerebral arteries in a dog experiment and a clinical observation. The method was tested by comparing the measured image of oblique view to the computed ...

中文摘要翻译待生成

For noisy X-ray fluoroscopy image sequences the authors quantitatively evaluated image quality after digital temporal filtering to reduce noise. Using an experimental paradigm called a reference/test adaptive forced-choice method the authors compared detectability of stationary low-contrast disks in filtered and un-filtered, computer-generated image sequences. In the first experiment, a low-pass f...

对于噪声较大的X射线透视图像序列，作者通过数字时间滤波来降低噪声，并对其图像质量进行了定量评估。采用一种称为参考/测试自适应强制选择方法的实验范式，作者比较了滤波和未滤波计算机生成图像序列中静止低对比度圆盘的可见性。在第一个实验中，低通滤波...

We describe a fast and globally convergent fully four-dimensional incremental gradient (4DIG) algorithm to estimate the continuous-time tracer density from list mode positron emission tomography (PET) data. Detection of 511-keV photon pairs produced by positron-electron annihilation is modeled as an inhomogeneous Poisson process whose rate function is parameterized using cubic $B$-splines. The ra...

我们描述了一种快速且全局收敛的全四维增量梯度（4DIG）算法，用于从列表模式正电子发射断层扫描（PET）数据中估计连续时间示踪剂密度。将正电子-电子湮灭产生的511 keV光子对检测建模为非齐次泊松过程，其速率函数使用三次B样条参数化。

The radial derivative of the three-dimensional (3-D) radon transform of an object is an important intermediate result in many analytically exact cone-beam reconstruction algorithms. The authors briefly review Grangeat's (1991) approach for calculating radon derivative data from cone-beam projections and then present a new, efficient method for 3-D radon inversion, i.e., reconstruction of the image...

物体的三维Radon变换的径向导数是许多解析精确锥束重建算法中的重要中间结果。作者简要回顾了Grangeat（1991）从锥束投影计算Radon导数数据的方法，然后提出了一种新的、高效的三维Radon反演方法，即图像重建...

An analytical framework of error propagation for diffusion tensor imaging (DTI) is presented. Using this framework, any uncertainty of interest related to the diffusion tensor elements or to the tensor-derived quantities such as eigenvalues, eigenvectors, trace, fractional anisotropy (FA), and relative anisotropy (RA) can be analytically expressed and derived from the noisy diffusion-weighted sign...

提出了一种针对扩散张量成像（DTI）的误差传播分析框架。利用该框架，任何与扩散张量元素或张量衍生量（如特征值、特征向量、迹、分数各向异性（FA）和相对各向异性（RA））相关的不确定性都可以从噪声扩散加权信号中解析表达和推导出来。

A method is presented for correcting PET images for the blurring caused by variations in the depth-of-interaction in position-sensitive gamma ray detectors. The method uses an empirically determined, tabulated relationship between depth-of-interaction and most probable pulse-height to estimate the unknown depth from the measured pulse-height for each detected gamma ray. In the case of one fine-cut...

中文摘要翻译待生成

The recently developed S-transform (ST) combines features of the Fourier and Wavelet transforms; it reveals frequency variation over both space and time. It is a potentially powerful tool that can be applied to medical image processing including texture analysis and noise filtering. However, calculation of the ST is computationally intensive, making conventional implementations too slow for many m...

最近开发的S变换（ST）结合了傅里叶变换和小波变换的特性；它揭示了频率在空间和时间上的变化。这是一个潜在强大的工具，可应用于医学图像处理，包括纹理分析和噪声滤波。然而，ST的计算量很大，使得传统实现对于许多医学应用而言太慢。

True three dimensional (3-D) volume reconstruction from fully 3-D data in positron emission tomography (PET) has only a limited clinical use because of its large computational burden. Fourier rebinning (FORE) of the fully 3-D data into a set of 2-D sinogram data decomposes the 3-D reconstruction process into multiple 2-D reconstructions of decoupled 2-D image slices, thus substantially decreasing ...

真正的三维（3-D）体积重建在全三维正电子发射断层扫描（PET）数据中由于巨大的计算负担而仅具有有限的临床应用。将全三维数据通过傅里叶重排（FORE）分解为一组二维正弦图数据，将三维重建过程分解为多个解耦的二维图像切片的二维重建，从而大大减少计算量。

The use of selective internal radiation therapy for treatment of hepatocellular carcinoma and liver metastases using Y-90 labeled microspheres has become an effective and widely used treatment regimen. However, dosimetric evaluations of this treatment are still primitive as uniform distribution models based only on injected activity are often used. This investigation attempts to quantify the effec...

使用Y-90标记微球的选择性内放射疗法治疗肝细胞癌和肝转移瘤已成为一种有效且广泛应用的治疗方案。然而，该治疗的剂量学评估仍然较为原始，因为通常仅基于注射活度的均匀分布模型。本研究试图量化...

Optoacoustic tomography (OAT), also known as photoacoustic tomography, is an emerging computed biomedical imaging modality that exploits optical contrast and ultrasonic detection principles. Iterative image reconstruction algorithms that are based on discrete imaging models are actively being developed for OAT due to their ability to improve image quality by incorporating accurate models of the im...

光声层析成像（OAT），也称为光声断层扫描，是一种新兴的计算生物医学成像模式，利用光学对比度和超声检测原理。基于离散成像模型的迭代图像重建算法正在积极开发中，因为它们能够通过纳入准确的成像模型来提高图像质量...

A new scheme for denoising magnetic resonance spectroscopy (MRS) signals is presented. This scheme is based on projecting noisy MRS signals in different domains, consecutively, and performing noise filtering operations in these domains. The domains are chosen such that the noise portion, which is inseparable from the desired signal in one domain, is separable in the other. A set of stable, linear,...

提出了一种用于磁共振波谱（MRS）信号去噪的新方案。该方案基于将噪声MRS信号连续投影到不同域中，并在这些域中执行噪声滤波操作。选择这些域使得在一个域中与期望信号不可分离的噪声部分在另一个域中是可分离的。一组稳定的、线性的...

In cone-beam computerized tomography (CT), projections acquired with the focal spot constrained on a planar orbit cannot provide a complete set of data to reconstruct the object function exactly. There are severe distortions in the reconstructed noncentral transverse planes when the cone angle is large. In this work, a new method is proposed which can obtain a complete set of data by acquiring con...

在锥束计算机断层扫描（CT）中，焦点在平面轨道上采集的投影无法提供完整的数据集来精确重建物体函数。当锥角较大时，重建的非中心横向平面存在严重畸变。本文提出了一种新方法，通过采集...

Identification of anatomical features is a necessary step for medical image analysis. Automatic methods for feature identification using conventional pattern recognition techniques typically classify an object as a member of a predefined class of objects, but do not attempt to recover the exact or approximate shape of that object. For this reason, such techniques are usually not sufficient to iden...

中文摘要翻译待生成

A new approach is proposed for registering a set of histological coronal two-dimensional images of a rat brain sectional material with coronal sections of a three-dimensional brain atlas, an intrinsic step and a significant challenge to current efforts in brain mapping and multimodal fusion of experimental data. The alignment problem is based on matching external contours of the brain sections, an...

提出了一种新方法，用于将一组大鼠大脑冠状组织学二维切片图像与三维脑图谱的冠状切片进行配准，这是当前脑图谱绘制和多模式实验数据融合工作中的关键一步和重大挑战。配准问题基于匹配脑切片的外部轮廓，

The ideas of parallel imaging techniques, designed to shorten the acquisition time by the simultaneous use of multiple receive coils, can be adapted for parallel transmission of a spatially selective multidimensional RF pulse. In analogy to data acquisition, a multidimensional RF pulse follows a certain trajectory in k-space. Shortening this trajectory shortens the pulse duration. The use of multi...

并行成像技术的思路，通过同时使用多个接收线圈来缩短采集时间，可以适用于空间选择性多维射频脉冲的并行传输。与数据采集类似，多维射频脉冲在k空间中遵循特定轨迹。缩短该轨迹可缩短脉冲持续时间。使用多...

Transmit $B_1^+$ field homogenization in high-field ( ${>}3.0$ T) human magnetic resonance imaging (MRI) is challenging due to radio-frequency wavelength effects. An approach based on appropriately coupling surface coils to a volume coil was investigated. Electromagnetic simulation results demonstrated the feasibility and effectiveness of this method in proton MRI of the human head at 7.0 T.

中文摘要翻译待生成

Interior-point methods have been successfully applied to a wide variety of linear and nonlinear programming applications. This paper presents a class of algorithms, based on path-following interior-point methodology, for performing regularized maximum-likelihood (ML) reconstructions on three-dimensional (3-D) emission tomography data. The algorithms solve a sequence of subproblems that converge to...

内点方法已成功应用于各种线性和非线性规划问题。本文提出了一类基于路径跟踪内点方法的算法，用于在三维发射断层扫描数据上执行正则化最大似然重建。这些算法求解一系列子问题，这些子问题收敛到...

This paper describes a region-growing algorithm for the segmentation of large lesions in T/sub 1/-weighted magnetic resonance (MR) images of the head. The algorithm involves a gray level similarity criterion to expand the region and a size criterion to prevent from over-growing outside the lesion. The performance of tile algorithm is evaluated and validated on a series of pathologic three-dimensio...

本文描述了一种用于头部T1加权磁共振（MR）图像中大病变分割的区域生长算法。该算法采用灰度相似性准则来扩展区域，并利用尺寸准则防止区域过度生长到病变外部。该算法的性能在一系列病理三维...上进行了评估和验证。

Digital image-based elasto-tomography (DIET) is a prototype system for breast cancer screening. A breast is imaged while being vibrated, and the observed surface motion is used to infer the internal stiffness of the breast, hence identifying tumors. This paper describes a computer vision system for accurately measuring 3-D surface motion. A model-based segmentation is used to identify the profile ...

基于数字图像的弹性断层扫描(DIET)是一种用于乳腺癌筛查的原型系统。在乳房振动时对其进行成像，通过观察到的表面运动来推断乳房内部硬度，从而识别肿瘤。本文描述了一种用于精确测量三维表面运动的计算机视觉系统。采用基于模型的分割来识别轮廓……