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The adaptive contrast enhancement (ACE) algorithm, which uses contrast gains (CGs) to adjust the high-frequency components of images, is a well-known technique for medical image processing. Conventionally, the CG is either a constant or inversely proportional to the local standard deviation (LSD). However, it is known that conventional approaches entail noise overenhancement and ringing artifacts....

自适应对比度增强（ACE）算法利用对比度增益（CG）调整图像的高频分量，是一种众所周知的医学图像处理技术。传统上，CG要么是常数，要么与局部标准差（LSD）成反比。然而，众所周知，传统方法会导致噪声过度增强和振铃伪影...

Mixture models are commonly used in the statistical segmentation of images. For example, they can be used for the segmentation of structural medical images into different matter types, or of statistical parametric maps into activating and nonactivating brain regions in functional imaging. Spatial mixture models have been developed to augment histogram information with spatial regularization using ...

混合模型常用于图像的统计分割。例如，它们可用于将结构医学图像分割成不同的物质类型，或将统计参数图分割为功能成像中的激活和非激活脑区域。空间混合模型已被开发出来，通过空间正则化增强直方图信息，使用...

A computationally efficient technique is described for the simultaneous removal of ghosting and geometrical distortion artifacts in echo-planar imaging (EPI) utilizing a multiecho, gradient-echo reference scan. Nyquist ghosts occur in EPI reconstructions because odd and even lines of k-space are acquired with opposite polarity, and experimental imperfections such as gradient eddy currents, imperfe...

描述了一种计算效率高的技术，用于利用多回波梯度回波参考扫描同时消除回波平面成像（EPI）中的鬼影和几何失真伪影。奈奎斯特鬼影出现在EPI重建中，因为k空间奇偶行以相反的极性采集，并且由于梯度涡流等实验缺陷，不完美的...

Motivated by the observation that the diagonal pattern of intensity nonuniformity usually associated with linearly polarized radio-frequency (RF) coils is often present in neurological scans using circularly polarized coils, a theoretical analysis has been conducted of the intensity nonuniformity inherent in imaging an elliptically shaped object using 1.5-T magnets and circularly polarized RF coil...

受观察到的现象启发，即通常与线性极化射频线圈相关的强度非均匀性的对角模式常常出现在使用圆极化线圈的神经扫描中，我们对使用1.5T磁体和圆极化射频线圈对椭圆形状物体进行成像时固有的强度非均匀性进行了理论分析...

Gastrointestinal (GI) tract examination with spiral/helical computed tomography (CT) is currently performed by slice-based inspection of axial images. CT colography is a recent advance which allows an intraluminal visualization of the colon, similar to endoscopy. Various rendering algorithms have been developed with promising results, however navigation through the complex, tortuous anatomy of the...

目前，螺旋/螺旋计算机断层扫描（CT）检查胃肠道是通过逐层检查轴向图像进行的。CT结肠成像是一项最新进展，它允许像内窥镜检查一样对结肠进行腔内可视化。已经开发了各种渲染算法，并取得了有希望的结果，然而在复杂、曲折的解剖结构中导航……

The aim of the experiments was to check the feasibility of pulmonary perfusion imaging by functional electrical impedance tomography (EIT) and to compare the EIT findings with electron beam computed tomography (EBCT) scans. In three pigs, a Swan-Ganz catheter was positioned in a pulmonary artery branch and hypertonic saline solution or a radiographic contrast agent were administered as boli through the distal or proximal openings of the catheter. During the administration through the proximal opening, the balloon at the tip of the catheter was either deflated or inflated. The latter case represented a perfusion defect. The series of EIT scans of the momentary distribution of electrical impedance within the chest were obtained during each saline bolus administration at a rate of 13/s. EBCT scans were acquired at a rate of 3.3/s during bolus administrations of the radiopaque contrast material under the same steady-state conditions. The EIT data were used to generate local time-impedance curves and functional EIT images showing the perfusion of a small lung region, both lungs with a perfusion defect and complete both lungs during bolus administration through the distal and proximal catheter opening with an inflated or deflated balloon, respectively. The results indicate that EIT imaging of lung perfusion is feasible when an electrical impedance contrast agent is used.

实验的目的是检验通过功能性电阻抗断层成像（EIT）进行肺灌注成像的可行性，并将EIT结果与电子束计算机断层扫描（EBCT）进行比较。在三头猪体内，将Swan-Ganz导管置于肺动脉分支，并通过导管的远端或近端开口注射高渗盐水溶液或放射造影剂。通过近端开口注射时，导管尖端的球囊要么放气要么充气。后一种情况代表灌注缺损。在每次盐水团注过程中，以13次/秒的速率获取胸部内电阻抗瞬时分布的EIT扫描序列。在相同稳态条件下，以3.3次/秒的速率获取注射放射造影剂团注时的EBCT扫描。EIT数据用于生成局部时间-阻抗曲线和功能性EIT图像，这些图像分别显示了在通过导管远端和近端开口（球囊充气或放气）注射团注时，小肺区域、双肺伴灌注缺损以及完整双肺的灌注情况。结果表明，当使用电阻抗造影剂时，EIT肺灌注成像是可行的。

Examines the use of the algebraic reconstruction technique (ART) and related techniques to reconstruct 3-D objects from a relatively sparse set of cone-beam projections. Although ART has been widely used for cone-beam reconstruction of high-contrast objects, e.g., in computed angiography, the work presented here explores the more challenging low-contrast case which represents a little-investigated...

研究了使用代数重建技术（ART）及相关技术从相对稀疏的锥束投影中重建三维物体。尽管ART已广泛应用于高对比度物体的锥束重建，例如在计算机断层血管造影中，但本文探讨了更具挑战性的低对比度情况，这是一个研究较少的领域。

A new class of acquisition schemes for helical cone-beam computed tomography (CB-CT) scanning is introduced, and their effect on the reconstruction methods is analyzed. These acquisition schemes are based on a new detector shape that is bounded by the helix. It will be shown that the data acquired with these schemes are compatible with exact reconstruction methods, and the adaptation of exact reco...

介绍了一类用于螺旋锥束计算机断层扫描（CB-CT）的新型采集方案，并分析了它们对重建方法的影响。这些采集方案基于一种由螺旋线界定的新型探测器形状。将证明这些方案采集的数据与精确重建方法兼容，并且精确重建方法的适应...

Grayscale inhomogeneities in magnetic resonance (MR) images confound quantitative analysis of these images. Homomorphic unsharp masking and its variations have been commonly used as a post-processing method to remove inhomogeneities in MR images, However, little data is available in the literature assessing the relative effectiveness of these algorithms to remove inhomogeneities, or describing how...

磁共振（MR）图像中的灰度不均匀性会干扰这些图像的定量分析。同态反锐化掩膜及其变体常被用作后处理方法以消除MR图像中的不均匀性，然而，文献中关于评估这些算法在消除不均匀性方面的相对有效性，或描述如何……的数据很少。

Deformable models, which include deformable contours (the popular snakes) and deformable surfaces, are a powerful model-based medical image analysis technique. The authors develop a new class of deformable models by formulating deformable surfaces in terms of an affine cell image decomposition (ACID). The authors' approach significantly extends standard deformable surfaces, while retaining their i...

可变形模型，包括可变形轮廓（流行的蛇形模型）和可变形曲面，是一种强大的基于模型的医学图像分析技术。作者通过仿射细胞图像分解（ACID）来构建可变形曲面，从而开发了一类新的可变形模型。作者的方法显著拓展了标准可变形曲面，同时保留了其...

Magnetic particle imaging allows to determine the spatial distribution of magnetic nanoparticles in vivo. The system matrix in magnetic particle imaging is commonly acquired in a tedious calibration scan and requires to measure the system response at numerous positions in the field-of-view. In this paper, we propose a method that significantly reduces the number of required calibration scans. It e...

磁粒子成像能够确定体内磁性纳米颗粒的空间分布。磁粒子成像中的系统矩阵通常通过繁琐的校准扫描获取，需要在视场中的多个位置测量系统响应。在本文中，我们提出了一种显著减少所需校准扫描次数的方法。它...

For pt. I see ibid., vol. 21, no. 7, p. 823-8 (2002). Microwave-induced thermoacoustic tomography (TAT) in a cylindrical configuration is developed to image biological tissue. Thermoacoustic signals are acquired by scanning a flat ultrasonic transducer. Using a new expansion of a spherical wave in cylindrical coordinates, we apply the Fourier and Hankel transforms to TAT and obtain an exact freque...

第一部分见同刊，第21卷，第7期，第823-8页（2002年）。开发了圆柱配置下的微波诱导热声层析成像（TAT）以对生物组织成像。通过扫描平面超声换能器获取热声信号。利用柱坐标下球面波的新展开式，我们将傅里叶变换和汉克尔变换应用于TAT，并获得了精确的频域重建公式。

Single photon emission computed tomography (SPECT) imaging with /sup 201/Tl or /sup 99m/Tc agent is used to assess the location or the extent of myocardial infarction or ischemia. A method is proposed to decrease the effect of operator variability in the visual or quantitative interpretation of scintigraphic myocardial perfusion studies. To effect this, the patient's myocardial images (target case...

使用/sup 201/Tl或/sup 99m/Tc试剂的单光子发射计算机断层扫描(SPECT)成像用于评估心肌梗死或缺血的位置或程度。提出了一种方法以减少操作员变异性在闪烁心肌灌注研究的视觉或定量解释中的影响。为了实现这一点，患者的心肌图像(目标病例...)

A better knowledge of the kinematics behavior of total knee replacement (TKR) during activity still remains a crucial issue to validate innovative prosthesis designs and different surgical strategies. Tools for more accurate measurement of in vivo kinematics of knee prosthesis components are therefore fundamental to improve the clinical outcome of knee replacement. In the present study, a novel mo...

更好地了解全膝关节置换术（TKR）在活动中的运动学行为仍然是验证创新假体设计和不同手术策略的关键问题。因此，用于更准确测量膝关节假体组件体内运动学的工具对于改善膝关节置换的临床结果至关重要。在本研究中，一种新颖的...

This paper deals with an automated method for the simultaneous correction of patient motion and gray values prior to subtraction in digitized angiography. The algorithm consists of maximizing the deterministic sign change (DSC) criterion with respect to three registration parameters (two translational shifts and one constant value added to the pixel values of the image with contrast medium). This ...

中文摘要翻译待生成

Lossless compression techniques are essential in archival and communication of medical images. Here, a new segmentation-based lossless image coding (SLIC) method is proposed, which is based on a simple but efficient region growing procedure. The embedded region growing procedure produces an adaptive scanning pattern for the image with the help of a very-few-bits-needed discontinuity index map. Alo...

无损压缩技术对于医学图像的存档和通信至关重要。本文提出了一种新的基于分割的无损图像编码（SLIC）方法，该方法基于一个简单但高效的区域生长过程。嵌入的区域生长过程借助一个只需极少比特的不连续性指标图，为图像生成自适应扫描模式。

A method is presented that uses a vectorial multiscale feature image for wave front propagation between two or more user defined points to retrieve the central axis of tubular objects in digital images. Its implicit scale selection mechanism makes the method more robust to overlap and to the presence of adjacent structures than conventional techniques that propagate a wave front over a scalar image representing the maximum of a range of filters. The method is shown to retain its potential to cope with severe stenoses or imaging artifacts and objects with varying widths in simulated and actual two-dimensional angiographic images.

提出了一种方法，利用矢量多尺度特征图像在两个或多个用户定义点之间进行波前传播，以获取数字图像中管状物体的中心轴。其隐含的尺度选择机制使得该方法比传统技术在波前传播于表示滤波器范围最大值的标量图像时，更能抵抗重叠和相邻结构的存在。该方法在模拟和实际二维血管造影图像中显示出处理严重狭窄、成像伪影以及宽度变化物体的潜力。

The authors propose a new 2-D point source scattering deconvolution method. The cross-plane scattering is incorporated into the algorithm by modeling a scattering point source function. In the model, the scattering dependence on axial and transaxial directions is reflected in the exponential fitting parameters, and these parameters are directly estimated from a limited number of measured point res...

中文摘要翻译待生成

This paper reports a novel method for fully automated segmentation that is based on description of shape and its variation using point distribution models (PDM's). An improvement of the active shape procedure introduced by Cootes and Taylor (1997) to find new examples of previously learned shapes using PDM's is presented. The new method for segmentation and interpretation of deep neuroanatomic str...

本文报告了一种基于点分布模型（PDM）的形状及其变异描述的全自动分割新方法。提出了对Cootes和Taylor（1997）引入的主动形状过程的改进，以使用PDM发现先前学习形状的新实例。介绍了用于深部神经解剖结构分割和解释的新方法...

This paper addresses the long object problem in helical cone-beam computed tomography. The authors present the PHI-method, a new algorithm for the exact reconstruction of a region-of-interest (ROI) of a long object from axially truncated data extending only slightly beyond the ROI. The PHI-method is an extension of the Radon-method, published by Kudo et al. in Phys. in Med. and Biol., vol. 43, p. ...

本文解决了螺旋锥束计算机断层扫描中的长物体问题。作者提出了PHI方法，这是一种新算法，用于从仅略超出感兴趣区域（ROI）的轴向截断数据中精确重建长物体的感兴趣区域。PHI方法是Radon方法的扩展，由Kudo等人在《Phys. in Med. and Biol.》第43卷中发表。

Iterative maximum likelihood (ML) transmission computed tomography algorithms have distinct advantages over Fourier-based reconstruction, but unfortunately require increased computation time. The convex algorithm is a relatively fast iterative ML algorithm but it is nevertheless too slow for many applications. Therefore, an acceleration of this algorithm by using ordered subsets of projections is ...

迭代最大似然（ML）透射计算机断层扫描算法相比基于傅里叶的重建具有明显优势，但不幸的是需要增加计算时间。凸算法是一种相对快速的迭代ML算法，但对于许多应用而言仍然太慢。因此，通过使用投影的有序子集来加速该算法...

Computerized analysis of the tongue surface movement can provide valuable information to speech and swallowing research. Ultrasound technology is currently the most attractive modality for the tongue imaging mainly because of its high video frame rate. However, problems with ultrasound imaging, such as noise and echo artifacts, refractions, and unrelated reflections pose significant challenges for...

舌头表面运动的计算机化分析可以为言语和吞咽研究提供有价值的信息。超声技术目前是舌头成像最具吸引力的模态，主要因为其高视频帧率。然而，超声成像的问题，如噪声和回声伪影、折射以及无关反射，给...带来了重大挑战。

Due to vessel overlap and foreshortening, multiple projections are necessary to adequately evaluate the coronary tree with arteriography. Catheter-based interventions can only be optimally performed when these visualization problems are successfully solved. The traditional method provides multiple selected views in which overlap and foreshortening are subjectively minimized based on two dimensional (2-D) projections. A pair of images acquired from routine angiographic study at arbitrary orientation using a single-plane imaging system were chosen for three-dimensional (3-D) reconstruction. After the arterial segment of interest (e.g., a single coronary stenosis or bifurcation lesion) was selected, a set of gantry angulations minimizing segment foreshortening was calculated. Multiple computer-generated projection images with minimized segment foreshortening were then used to choose views with minimal overlapped vessels relative to the segment of interest. The optimized views could then be utilized to guide subsequent angiographic acquisition and interpretation. Over 800 cases of coronary arterial trees have been reconstructed, in which more than 40 cases were performed in room during cardiac catheterization. The accuracy of 3-D length measurement was confirmed to be within an average root-mean-square (rms) 3.5% error using eight different pairs of angiograms of an intracoronary guidewire of 105-mm length with eight radiopaque markers of 15-mm interdistance. The accuracy of similarity between the additional computer-generated projections versus the actual acquired views was demonstrated with the average rms errors of 3.09 mm and 3.13 mm in 20 LCA and 20 RCA cases, respectively. The projections of the reconstructed patient-specific 3-D coronary tree model can be utilized for planning optimal clinical views: minimal overlap and foreshortening. The assessment of lesion length and diameter narrowing can be optimized in both interventional cases and studies of disease progression and regression.

由于血管重叠和缩短，需要多个投影来充分评估冠状动脉造影图像。只有当这些可视化问题得到成功解决时，基于导管的介入治疗才能最佳地进行。传统方法提供多个选定视图，在这些视图中，基于二维投影主观地最小化重叠和缩短。选择常规血管造影研究中使用单平面成像系统以任意方向获取的一对图像进行三维重建。在选定感兴趣的动脉段（例如，单个冠状动脉狭窄或分叉病变）后，计算一组最小化段缩短的机架角度。然后使用多个计算机生成的投影图像（具有最小化的段缩短）来选择相对于感兴趣段具有最小重叠血管的视图。然后可以利用优化视图来指导后续的血管造影采集和解释。已经重建了超过800例冠状动脉树，其中超过40例在心脏导管插入术期间在手术室中进行。三维长度测量的准确性通过使用八对不同长度的冠状动脉内导丝（105毫米，8个不透射线标记，间隔15毫米）的血管造影图得到确认，平均均方根误差为3.5%。附加计算机生成投影与实际获取视图之间的相似性准确性通过20例左冠状动脉和20例右冠状动脉病例的平均均方根误差分别为3.09毫米和3.13毫米得到证明。重建的患者特异性三维冠状动脉树模型的投影可用于规划最佳临床视图：最小重叠和缩短。病变长度和直径狭窄的评估可以在介入病例以及疾病进展和退化的研究中得到优化。

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...

A method is presented which aids the clinician in obtaining quantitative measures and a three-dimensional (3-D) representation of vessels from 3-D angiographic data with a minimum of user interaction. Based on two user defined starting points, an iterative procedure tracks the central vessel axis. During the tracking process, the minimum diameter and a surface rendering of the vessels are computed...

提出了一种方法，帮助临床医生以最少的用户交互从三维血管造影数据中获取血管的定量测量和三维表示。基于两个用户定义的起始点，迭代过程追踪血管中心轴线。在追踪过程中，计算血管的最小直径并生成表面渲染。