Volume 21, Issue 7

Reconstruction-based microwave-induced thermoacoustic tomography in a spherical configuration is presented. Thermoacoustic waves from biological tissue samples excited by microwave pulses are measured by a wide-band unfocused ultrasonic transducer, which is set on a spherical surface enclosing the sample. Sufficient data are acquired from different directions to reconstruct the microwave absorption distribution. An exact reconstruction solution is derived and approximated to a modified backprojection algorithm. Experiments demonstrate that the reconstructed images agree well with the original samples. The spatial resolution of the system reaches 0.5 mm.

提出了一种基于重建的球面构型微波诱导热声断层扫描方法。由微波脉冲激发生物组织样本产生的热声波，通过一个放置在包围样本的球面上的宽带非聚焦超声换能器进行测量。从不同方向获取足够的数据以重建微波吸收分布。推导出精确的重建解，并近似为改进的反投影算法。实验表明，重建图像与原始样本吻合良好。系统的空间分辨率达到0.5毫米。

We report an exact and fast Fourier-domain reconstruction algorithm for thermoacoustic tomography in a planar configuration assuming thermal confinement and constant acoustic speed. The effects of the finite size of the detector and the finite length of the excitation pulse are explicitly included in the reconstruction algorithm. The algorithm is numerically and experimentally verified. We also de...

我们报道了一种在平面配置下假设热约束和恒定声速的热声层析成像的精确快速傅里叶域重建算法。检测器的有限尺寸和激励脉冲的有限长度的影响被明确地包含在重建算法中。该算法得到了数值和实验验证。我们还...

The quantitative estimation of regional cardiac deformation from three-dimensional (3-D) image sequences has important clinical implications for the assessment of viability in the heart wall. We present here a generic methodology for estimating soft tissue deformation which integrates image-derived information with biomechanical models, and apply it to the problem of cardiac deformation estimation...

从三维(3D)图像序列中定量估计区域心脏形变对于评估心壁活力具有重要的临床意义。我们提出了一种通用的软组织形变估计方法，该方法将图像衍生信息与生物力学模型相结合，并将其应用于心脏形变估计问题。

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。

Traditional quantitative coronary angiography is performed on two-dimensional (2-D) projection views. These views are chosen by the angiographer to minimize vessel overlap and foreshortening. With 2-D projection views that are acquired in this nonstandardized fashion, however, there is no way to know or estimate how much error occurs in the QCA process. Furthermore, coronary arteries possess a cur...

传统的定量冠状动脉造影是在二维（2-D）投影视图上进行的。这些视图由血管造影师选择，以最小化血管重叠和缩短。然而，以这种非标准化方式获取的二维投影视图，无法知道或估计QCA过程中发生的误差有多大。此外，冠状动脉具有弯曲...

This paper presents a new method of knowledge gathering for decision support in image understanding based on information extracted from the dynamics of saccadic eye movements. The framework involves the construction of a generic image feature extraction library, from which the feature extractors that are most relevant to the visual assessment by domain experts are determined automatically through ...

本文提出了一种基于眼跳运动动力学信息提取的图像理解决策支持知识收集新方法。该框架包括构建通用图像特征提取库，从中自动确定与领域专家视觉评估最相关的特征提取器……

Near-infrared (NIR) diffuse tomography is an emerging method for imaging the interior of tissues to quantify concentrations of hemoglobin and exogenous chromophores noninvasively in vivo. It often exploits an optical diffusion model-based image reconstruction algorithm to estimate spatial property values from measurements of the light flux at the surface of the tissue. In this study, mean-squared ...

近红外（NIR）漫射断层成像是一种新兴的方法，用于非侵入性地在体内成像组织内部，以量化血红蛋白和外源性色素的浓度。它通常利用基于光学扩散模型的图像重建算法，从组织表面的光通量测量中估计空间属性值。在本研究中，均方...

We compute unmeasured cone-beam projections from projections measured by a third-generation helical volumetric computed tomography system by solving a characteristic problem for an ultrahyperbolic differential equation [John (1938)]. By working in the Fourier domain, we convert the second-order PDE into a family of first-order ordinary differential equations. A simple first-order integration is us...

我们通过求解超双曲型微分方程[John (1938)]的特征问题，从第三代螺旋容积计算机断层扫描系统测量的投影中计算出未测量的锥束投影。通过在傅里叶域中工作，我们将二阶偏微分方程转换为一族一阶常微分方程。简单的一阶积分被用于...

For pt. I see ibid., vol. 21, no. 7, p. 755-63 (2002). Image error analysis of a diffuse near-infrared tomography (NIR) system has been carried out on simulated data using a statistical approach described in pt. I of this paper (Pogue et al., 2002). The methodology is used here with experimental data acquired on phantoms with a prototype imaging system intended for characterizing breast tissue. Re...

第一部分见同刊第21卷第7期第755-63页(2002年)。使用本文第一部分(Pogue等,2002)描述的统计方法，对模拟数据进行了漫射近红外断层成像(NIR)系统的图像误差分析。这里将该方法用于在旨在表征乳腺组织的原型成像系统上获取的仿体实验数据。

This paper reports on the clinical application of a system for recovering the time-varying three-dimensional (3-D) left-ventricular (LV) shape from multiview X-ray cineangiocardiograms. Considering that X-ray cineangiocardiography is still commonly employed in clinical cardiology and computational costs for 3-D recovery and visualization are rapidly decreasing, it is meaningful to develop a clinic...

本文报道了一种系统在临床中的应用，该系统从多视角X射线电影心血管造影中恢复时变三维左心室形状。考虑到X射线电影心血管造影在临床心脏病学中仍被广泛使用，且三维恢复和可视化的计算成本正在迅速降低，开发临床应用的系统具有重要意义...

The author reviews the history of medical image computing at his institute, summarizes the achievements, sketches some of the difficulties encountered, and draws conclusions that might be of interest especially to people new to the field. The origin and history section provides a chronology of this work, emphasizing the milestones reached during the past three decades. In accordance with the autho...

作者回顾了他所在研究所的医学图像计算历史，总结了取得的成就，简要描述了遇到的一些困难，并得出了可能对刚进入该领域的人特别感兴趣的结论。起源与历史部分提供了这项工作的编年史，强调了过去三十年达到的里程碑。

In this paper, errors and discrepancies in the subject paper [Cincotti et al. (2002)] are highlighted. A comment, concerning the axial resolution associated to the adopted processing procedure is also reported.

本文指出了主题论文[Cincotti等人(2002)]中的错误和差异。此外，还报告了一个关于所采用处理过程中轴向分辨率的评论。