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Rat brain images acquired with a small animal positron emission tomography (PET) camera and reconstructed with the three-dimensional (3-D) ordered-subsets expectation-maximization (OSEM) algorithm with resolution recovery have better quality when the brain is imaged by itself than when inside the head with surrounding background activity. The purpose of this study was to characterize the dependenc...

使用小动物正电子发射断层扫描（PET）相机获取并经三维有序子集期望最大化（OSEM）算法（具有分辨率恢复功能）重建的大鼠脑图像，当单独成像时比在头部内且有周围背景活动时质量更好。

An optical model for imaging the retina through cataracts has been developed. The images are treated as sample functions of stochastic processes. On the basis of the model a homomorphic Weiner filter can be designed that will optimally restore the cataractous image (in the mean-square-error sense). The design of the filter requires a priori knowledge of the statistics of either the cataract transm...

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The maximum intensity projection (MIP) is a popularly used algorithm for display of MRA images, but its performance has not been rigorously analyzed before. In this paper, four measures are proposed for the performance of the MIP algorithm and the quality of images projected from three-dimensional (3-D) data, which are vessel voxel projection probability, vessel detection probability, false vessel...

最大强度投影（MIP）是一种广泛用于显示MRA图像的算法，但其性能此前尚未得到严格分析。本文提出了四个指标来评估MIP算法的性能以及从三维（3-D）数据投影的图像质量，这些指标包括血管体素投影概率、血管检测概率、假血管...

Exact reconstruction from axially truncated cone-beam projections acquired with a helical vertex path is a challenging problem for which solutions are currently under investigation by some researchers. This paper deals with a difficult class of this problem called the long-object problem. Its purpose is to reconstruct a central region of interest (ROI) of a long object when the helical path extend...

从螺旋顶点路径获取的轴向截断锥束投影中进行精确重建是一个具有挑战性的问题，目前一些研究人员正在研究解决方案。本文讨论了该问题中的一个困难类别，称为长物体问题。其目的是在螺旋路径延伸时重建长物体的中心感兴趣区域。

High-resolution micro-computed tomography (CT) scanners now exist for imaging small animals. In particular, such a scanner can generate very large three-dimensional (3-D) digital images of the rat's hepatic vasculature. These images provide data on the overall structure and function of such complex vascular trees. Unfortunately, human operators have extreme difficulty in extracting the extensive v...

高分辨率显微计算机断层扫描（CT）扫描仪现已可用于小动物成像。特别是，这种扫描仪可以生成大鼠肝脏血管系统的非常大的三维（3-D）数字图像。这些图像提供了此类复杂血管树的整体结构和功能数据。不幸的是，人类操作员在提取广泛的血管结构时面临极大困难...

Leg ulcers are chronic skin a wounds that affect many people and take a long time to heal. The progress of wound healing and the effect of clinical treatments can he monitored partly by measuring the area of the wound. Measurements taken via manually based methods, such as using a computer pointing device to delineate the wound boundary in a digitized image, suffer from variations due to manual de...

腿部溃疡是影响许多人的慢性皮肤伤口，需要很长时间才能愈合。伤口愈合的进展和临床治疗效果可以通过测量伤口面积部分监测。通过手动方法进行的测量，例如使用计算机指点设备在数字化图像中描绘伤口边界，存在由于手动操作而导致的变异...

The authors derives an algorithm for reconstructing contours of an object from 3D cone beam X-ray data. By reducing the amount of the searched-for information, contours, or density jumps instead of the densities themselves, the authors are able to develop fast algorithms for data incomplete with respect to both the movement of the X-ray source and the detector reading. The method is related to loc...

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A new tomographic reconstruction method is proposed which permits the reconstruction of a region of interest within a slice from partially truncated scanning data. This method utilizes two types of source data, namely a series of truncated projections and the outline of the object's cross section. The principle of this algorithm is to estimate the outside area of truncation in one projection from ...

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Conventional X-ray tomosynthesis with film can provide a sagittal slice image with a single scan. This technique has the advantage of enabling reconstruction of a sagittal slice which is difficult to obtain from the X-ray CT system. However, only an image on the focal plane is obtained by a single scan. Furthermore, the image is degraded by superimpositions of the structures outside of the focal p...

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We studied dielectrical properties of canine myocardium during acute ischemia and hypoxia using dielectrical spectroscopy method at frequency spectrum from 100 kHz to 6 GHz. This study was conducted on a group of six canines with acute ischemia and seven canines with hypoxia. Hypoxia (10% for 30 min) decreases myocardial resistance (/spl rho/), while the dielectrical permittivity (/spl epsi/') of ...

我们采用介电谱方法，在100 kHz至6 GHz频率范围内研究了犬心肌在急性缺血和缺氧时的介电特性。本研究在一组六只急性缺血犬和七只缺氧犬上进行。缺氧（10% 30分钟）降低心肌电阻抗（ρ），而介电常数（ε'）...

The performance of photoacoustic microscopy (PAM) degrades due to the turbidity of the skull that introduces attenuation and distortion of both laser and stimulated ultrasound. In this manuscript, we demonstrated that a newly developed skull optical clearing solution (SOCS) could enhance not only the transmittance of light, but also that of ultrasound in the skull in vitro. Thus the photoacoustic ...

由于颅骨的混浊性导致激光和激发超声的衰减和畸变，光声显微镜（PAM）的性能下降。在本文中，我们证明了一种新开发的颅骨光学透明溶液（SOCS）不仅能增强颅骨中光的透过率，还能增强超声的透过率（体外实验）。因此，光声...

Describes a probabilistic framework for modeling single-trial functional magnetic resonance (fMR) images based on a parametric model for the hemodynamic response and Markov random field (MRF) image models. The model is fitted to image data by maximizing a lower bound on the log likelihood. The result is an approximate maximum a posteriori estimate of the joint distribution over the model parameter...

描述了一个基于血流动力学反应参数模型和马尔可夫随机场(MRF)图像模型对单次试验功能磁共振图像进行概率建模的框架。该模型通过最大化对数似然的下界来拟合图像数据。结果是对模型参数联合分布的近似最大后验估计。

Many image-reconstruction methods have been proposed to improve the spatial resolution of positron emission tomography (PET) images and, thus, to produce better quantification. However, these techniques, which are designed for static images, may be inadequate for good reconstruction from dynamic data. The authors present a simple, but effective, reconstruction approach intended specifically for dy...

已提出许多图像重建方法来提高正电子发射断层扫描（PET）图像的空间分辨率，从而产生更好的量化结果。然而，这些专为静态图像设计的技术可能不足以从动态数据中实现良好的重建。作者提出了一种简单而有效的重建方法，专门用于动态...

The ISRA of [1] is shown to be an iterative algorithm that aims to converge to the least-squares estimates of emission densities. Convergence is established in the case where a unique least-squares estimate exists that is, elementwise, strictly positive. It is pointed out that, in terms of asymptotic theory, the resulting estimators are inferior to the maximum likelihood estimators, for which the ...

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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...

A convolutional backprojection algorithm is derived for a fan beam geometry that has its center-of-rotation displaced from the midline of the fan beam. In single photon emission computed tomography (SPECT), where a transaxial converging collimator is used with a rotating gamma camera, it is difficult to precisely align the collimator so that the mechanical center-of-rotation is colinear with the m...

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This paper reports the results of a complete circumferential scan of a human tooth and its underlying dentino-enamel junction using ultrasound at frequencies in the 10-MHz range. The imagery shows clearly a two-dimensional contour of the dentino-enamel junction with a depth and lateral resolution of approximately 100 /spl mu/m and 750 /spl mu/m, respectively. The resulting sonograph is compared wi...

本文报道了使用10 MHz频率范围内的超声波对人体牙齿及其下方的牙本质-釉质连接处进行完整圆周扫描的结果。图像清晰地显示了牙本质-釉质连接的二维轮廓，深度分辨率约为100微米，横向分辨率约为750微米。生成的声像图与...进行比较。

An artificial neural network has been developed to reconstruct quantitative single photon emission computed tomographic (SPECT) images. The network is trained with an ideal projection-image pair to learn a shift-invariant weighting (filter) for the projections. Once trained, the network produces weighted projections as a hidden layer when acquired projection data are presented to its input. This h...

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A simple and yet effective method for finding the borders of tumors is presented as an initial step towards the diagnosis of skin tumors from their color images. The method makes use of an adaptive color metric from the red, green, and blue planes that contains information for discriminating the tumor from the background. Using this suitable coordinate transformation, the image is segmented. The t...

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Motion and deformation analysis of the myocardium are of utmost interest in cardiac imaging. Part of the research is devoted to the estimation of the heart function by analysis of the shape changes of the left-ventricular endocardial surface. However, most clinically used shape-based approaches are often two-dimensional (2-D) and based on the analysis of the shape at only two cardiac instants. Thr...

心肌的运动和形变分析在心脏成像中至关重要。部分研究致力于通过分析左心室内膜表面的形状变化来评估心脏功能。然而，大多数临床使用的基于形状的方法通常是二维（2-D）的，并且仅基于两个心脏瞬间的形状分析。...

Describes a method for identification of brain structures from MRI data sets. The bulk of the paper concerns an automatic system for finding the anterior and posterior commissures [(AC) and (PC)] in the midsagittal plane. These landmarks are key for the definition of the Talairach space, commonly used in stereotactic neurosurgery, in the definition of common coordinate systems for the pooling of f...

描述了一种从MRI数据集中识别脑结构的方法。论文主要涉及一个自动系统，用于在正中矢状面上寻找前连合和后连合。这些标志点对于定义Talairach空间至关重要，该空间常用于立体定向神经外科以及定义用于汇总数据的共同坐标系。

To noninvasively quantify tissue elasticity for differentiating malignancy of soft tissue, the authors previously proposed a two-dimensional (2-D) mechanical inverse problem in which simultaneous partial differential equations (PDE's) represented the target distribution globally of relative shear moduli with respect to reference shear moduli such that the relative values could be determined from s...

为了无创量化组织弹性以区分软组织恶性，作者先前提出了一个二维（2-D）力学逆问题，其中联立偏微分方程（PDE）全局地表示了相对于参考剪切模量的相对剪切模量目标分布，从而可以从应变测量确定相对值...

In medical imaging it is common to reconstruct dense motion estimates, from sparse measurements of that motion, using some form of elastic spline (thin-plate spline, snakes and other deformable models, etc.). Usually the elastic spline uses only bending energy (second-order smoothness constraint) or stretching energy (first-order smoothness constraint), or a combination of the two. These elastic s...

在医学成像中，通常使用某种形式的弹性样条（薄板样条、蛇模型和其他可变形模型等）从稀疏的运动测量中重建稠密的运动估计。通常弹性样条只使用弯曲能量（二阶平滑约束）或拉伸能量（一阶平滑约束），或两者的组合。这些弹性...

A technique for the contrast enhancement of a picture is proposed. The method is derived from the entropy concept of information theory. The originality of the algorithm rests on the use of a local contrast to define the digital entropy. The basic idea of the treatment is to enhance the contrast by transforming the global entropy. The same technique can also be used for an adaptive smoothing proce...

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It is observed that when the homogeneity property of the ramp filter is used to derive a filtered backprojection algorithm in fan-beam tomography, the reconstructed images have nonstationary frequency components and nonstationary noise. When a short focal-length is used, higher frequency components are amplified more at the edge of the image than at the center of the image, resulting in higher noi...

观察到在扇束断层扫描中，利用斜坡滤波器的同质性推导滤波反投影算法时，重建图像具有非平稳的频率分量和非平稳噪声。使用短焦距时，图像边缘的高频分量比中心放大更多，导致更高噪声...