Recent results in color compositing of three-parameter magnetic resonance scans as a preoperative aid to the management of upper limb sarcomas

We report on improved image quality and some recent clinical results with volume-rendered, color composite, multiparameter, magnetic resonance (MR) datasets and their color histograms. In a previous article we demonstrated the major components of an interative visualization environment for multiparameterT ₁-,T ₂-, PD-weighted MR volume datasets. These are compositing of the three parametric volumes, color volume rendering of the resulting composite, interactive segmentation of the tissues based on color cluster statistics derived from display of the three-dimensional (3D) histogram, and head-tracking stereo diplay. We herein review the system design and describe improvements to the quality of the color volume rendering, in the display of the 3D color histogram data, and in the specification of the volume enderer’s opacity function. Finally, we report on some recent clinical results using our system.     

针对颈椎扩散张量成像数据的分析处理系统

针对颈椎病已成为我国常见病之一,并且扩散张量成像在临床诊断上得到越来越广泛应用的现状,提出基于ITK（insight segmentation and registration toolkit）和VTK（visualization toolkit）针对颈椎扩散张量成像数据特点构建分析处理平台,主要包含：数据输入模块、多平面显示模块、面绘制模块、DTI数据计算模块和交互模块.系统涵盖了扩散张量成像数据的计算、感兴趣区域选取、计算各向异性分数临床诊断指标等MRI图像处理流程,特别是在交互模块中,结合VTK与经典Snake算法给出了一种感兴趣区半自动选取的方法,为颈部扩散张量成像的后续图像处理奠定了基础.     

Prospective Real-Time Slice-by-Slice Motion Correction for fMRI in Freely Moving Subjects

Subject motion is still the major source of data quality degradation in functional magnetic resonance imaging (fMRI) studies. Established methods correct motion between successive repetitions based on the acquired imaging volumes either retrospectively or prospectively. A fast, highly accurate, and prospective real-time correction method for fMRI using external optical motion tracking has been implemented. The head position is determined by means of an optical stereoscopic tracking system. The method corrects motion during the acquisition of an fMRI time series on a slice-by-slice basis by continuously updating the imaging volume position to follow the motion of the head. This method allows the measurement of fMRI data in the presence of significant motion during the acquisition of a single volume. Even without intentional motion, fMRI signal stability is maintained and higher sensitivity to detect activation is achieved without reducing specificity. With significant motion, only the proposed approach allowed detection of brain activation. The results show that the new method is superior to image-based correction methods, which fail in the case of fast or excessive motion.     

Graph theoretical analysis of structural and functional connectivity MRI in normal and pathological brain networks

Graph theoretical analysis of structural and functional connectivity MRI data (ie. diffusion tractography or cortical volume correlation and resting-state or task-related (effective) fMRI, respectively) has provided new measures of human brain organization in vivo. The most striking discovery is that the whole-brain network exhibits “small-world” properties shared with many other complex systems (social, technological, information, biological). This topology allows a high efficiency at different spatial and temporal scale with a very low wiring and energy cost. Its modular organization also allows for a high level of adaptation. In addition, degree distribution of brain networks demonstrates highly connected hubs that are crucial for the whole-network functioning. Many of these hubs have been identified in regions previously defined as belonging to the default-mode network (potentially explaining the high basal metabolism of this network) and the attentional networks. This could explain the crucial role of these hub regions in physiology (task-related fMRI data) as well as in pathophysiology. Indeed, such topological definition provides a reliable framework for predicting behavioral consequences of focal or multifocal lesions such as stroke, tumors or multiple sclerosis. It also brings new insights into a better understanding of pathophysiology of many neurological or psychiatric diseases affecting specific local or global brain networks such as epilepsy, Alzheimer’s disease or schizophrenia. Graph theoretical analysis of connectivity MRI data provides an outstanding framework to merge anatomical and functional data in order to better understand brain pathologies.     

Cardiovascular phenotype characterization in mice by high resolution magnetic resonance imaging

9. Conclusion Due to its high temporal and spatial resolution, magnetic resonance imaging meets the requirements for accurate and robust in vivo visualization of the murine cardiovascular system. As an intrinsically three-dimensional imaging technique, it allows for quantification of LV volumes without relying on geometric models. Therefore, MRI is uniquely suited for the investigation of morphologic and functional changes in models of heart failure. The potential application of MRI in the mouse comprises visualization of cardiovascular anatomy and pathology in newborn and adult mice, detection of LV geometric and functional changes both acutely and chronically, visualization of cardiac microstructures such as cardiac valves and coronary arteries, and characterization and quantification of arteriosclerotic plaques in major murine arteries. Furthermore, MR spectroscopy applied to the mouse heart can give important information on in vivo myocardial metabolism. Thus, we feel confident that high resolution MRI may substantially contribute to the understanding of the basic mechanisms of a variety of cardiovascular diseases.     

Volumetric analysis of mice lungs in a clinical magnetic resonance imaging scanner

Small animal models are widely used to study various pathologies. Magnetic resonance imaging (MRI) allows investigation of these animals in a non-invasive way. Therefore, the aim of our study was to develop and evaluate a low-cost approach to measure lung volumes in small animal MRI using a clinical scanner and a specially designed RF coil. Five mice (three of an established emphysema model and two controls) were investigated in a 1.0-T clinical scanner using a specially built small animal saddle coil and three different three-dimensional sequences; overall imaging time was approximately 16 min. Lung volumes were calculated from these images using an interactive watershed transform algorithm for semi-automatic image segmentation. The gold standard for the volume measurement was water displacement after surgical explantation. MRI measured volumes correlated significantly with ex vivo measurements on the explanted lungs (r = 0.99 to 0.89; p < 0.05). Mean lung volume in emphysema model mice was larger than in controls. High-resolution, small animal MRI using a clinical scanner is feasible for volumetric analysis and provides an alternative to a dedicated small animal scanner.     

Open magnetic and electric graphic analysis.

The OMEGA software provides an analysis platform for user-independent, fast, and reproducible multimodal data analysis in one single software environment. Synergetic interactions pursued between the two functional imaging techniques fMRI and MEG use the morphological MRI recording as a basis for a common coordinate frame. In this way, direct interchange, comparison, and integration among the results of the different modalities have become feasible. The fMRI data analysis provides information about the localization of functional activity with low temporal resolution, whereas the MEG recording complements the corresponding time evolution with a high temporal resolution. The implementation of OMEGA allows the analyst to receive comprehensive MEG/fMRI results in a matter of minutes after the measurements have been completed. With OMEGA, the clinical researcher gets comprehensive information in a quick and standardized approach about the sites and the time course of neurological activation, which is useful for clinical applications and diagnostics.     

Surface and volume rendering techniques to display 3-D data

An overview of 3-D rendering techniques of medical data is presented. It is pointed out that volume rendering, and especially ray tracing, can be considered to be the most sophisticated and general method to display 3-D medical data. However, surface rendering still remains the most relevant technique for displaying noncommensurate information such as anatomical atlases. Hence, one of the main practical issues is to select the most appropriate image rendering method, based on the data acquisition modes and the medical relevance. The future of 3-D medical imaging is also discussed     

Graph-based semi-supervised learning

The recent years have witnessed a surge of interests in graph-based semi-supervised learning (GBSSL). In this paper, we will introduce a series of works done by our group on this topic including: 1) a method called linear neighborhood propagation (LNP) which can automatically construct the optimal graph; 2) a novel multilevel scheme to make our algorithm scalable for large data sets; 3) a generalized point charge scheme for GBSSL; 4) a multilabel GBSSL method by solving a Sylvester equation; 5) an information fusion framework for GBSSL; and 6) an application of GBSSL on fMRI image segmentation.     

Measurements of left ventricular dimensions using real-time acquisition in cardiac magnetic resonance imaging: comparison with conventional gradient echo imaging

This study investigates the use of real-time acquisition in cardiac magnetic resonance imaging (MRI) for measurements of left ventricular dimensions in comparison with conventional gradient echo acquisition. Thirty-one subjects with a variety of left ventricular morphologies to represent a typical clinical population were studied. Short-axis data sets of the left ventricle (LV) were acquired using a conventional turbo-gradient echo and an ultrafast hybrid gradient echo/echo planar sequence with acquisition in real-time. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) and left ventricular mass (LV mass) were measured. The agreement between the two acquisitions and interobserver, intraobserver and interstudy variabilities were determined. The bias between the two methods was 5.86 ml for EDV, 0.23 ml for ESV and 0.94% for EF. LV mass measurements were significantly lower with the real-time method (mean bias 14.38 g). This is likely to be the result of lower spatial resolution and chemical shift artefacts with the real-time method. Interobserver, intraobserver and interstudy variabilities were low for all parameters. In conclusion, real time acquisition in MRI can provide accurate and reproducible measurements of LV dimensions in subjects with normal as well as abnormal LV morphologies, but LV mass measurements were lower than with conventional gradient echo imaging. Presented in abstract form at the International Society of Magnetic Resonance in Medicine meeting in Denver, Colorado in April 2000.     

基于Google Earth的输电线路巡视无人机地面站监控系统

通过研究Google Earth电子地图的GIS二次开发技术,构造了无人机地面站电子地图显示与交互环境,结合无人机的物理-数学模型,定制无线数据通信协议,在Google Earth视图中对无人机进行三维飞行仿真和航迹实时跟踪显示,实现了地面站对空中无人机执行输电线路巡视飞行姿态和航路的全过程实时监控。     

Circuit Master: turnkey software for the introductory electricalengineering curriculum

A turnkey software system for the introductory electrical engineering curriculum is described in detail from a user's perspective. The system, Circuit Master, provides a structured, interactive, menu-driven environment that allows students to explore basic concepts in circuit and signal theory without requiring a background in computer programming. The system's interactive user interface and visual presentation format simultaneously display relationships between circuit components, pole-zero patterns. Bode plots, initial conditions, input/output signal waveforms, and input/output signal spectra for periodic and aperiodic signals. Simultaneous display of information for two sets of circuit components allows physical relationships, parametric changes, and sensitivity issues to be examined easily     

用电量数据的可视化研究综述

可视化技术是挖掘用电量数据中所蕴含丰富信息的关键技术手段,其相关研究热点集中在四个方面。用电量可视化分析形式主要有堆叠面积图等标准图表和一些自定义图表。用电量监控的可视化系统常用于建筑群和工业过程的能耗分析,其可以在用电行为纠正等方面发挥作用。用电异常的可视化包括异常计量用电数据和异常用电行为两个方面,以从源头提高计量数据质量,减少防窃电工作量。用电量数据挖掘的可视化研究集中在用电量预测中更实时的交互手段和用电用户分类中聚类分析算法的过程展现。以往各项的研究仍存在数据量较小、数据维度不高、未考虑外部因素等不足。未来应提升数据量级、扩大时空范围、融合多源数据、建立更细颗粒度用电数据模型。     

基于SVG的电力调度图形支撑平台设计与实现

可伸缩矢量图(SVG)是一种基于文本的标准图形描述语言,研究和建立一套基于SVG的图形系统是调度自动化系统图形信息共享和标准化的关键课题之一。基于图形数据一体化的思想提出了面向调度应用的图形模型,实现不同图形格式向SVG标准的转换及拓扑结构的自动生成,并探讨了SVG在调度可视化中的应用。基于SVG的图形系统可以作为不同系统间图形信息共享的平台,同时保证了图形发布的实时性,也为调度可视化提供了基础。     

fMRI neuroinformatics.

Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction, rudimentary analysis, and visualization tools are implemented in software controlling modern MRI scanners. Research in advanced methods for analysis of subtle activation patterns, realistic physiological modeling, or integration of data from multiple subjects is the basis for a lively research field and has led to the development of a large number of tools.     

High-resolution,high-throughput magnetic resonance imaging of mouse embryonic anatomy using a fast gradient-echo sequence

Embryonic development in normal and genetically modified mice is commonly analysed by histological sectioning. This procedure is time-consuming, prone to artefact, and results in the loss of three-dimensional (3D) information. Magnetic resonance imaging (MRI) of embryos has the potential of noninvasively acquiring a complete 3D data set. Published methods have used spin-echo techniques with inherently high signal-to-noise ratio (SNR); however, they required either perfusion of the embryo with a contrast agent, or prolonged acquisition times to improve contrast and resolution. Here, we show that a standard preparation (i.e. paraformaldehyde fixation) of 15.5 days post-coitum embryos followed by MRI using a fast gradient-echo sequence with T(1)-weighting achieves high resolution and high throughput for investigating mouse embryonic anatomy. 3D data sets were acquired in overnight experiments (<9 h) with an experimental resolution of approximately 25 microm(3). This spatial resolution is twofold higher than the values reported previously for comparable paraformaldehyde-fixed embryos, and it was obtained in less than a quarter of the time with sufficient SNR. Our approach combines speed, high resolution and contrast with a simple preparation technique and minimal operator time (<1 h). It allows rapid routine 3D characterisation of normal and abnormal mouse embryonic anatomy.     

Design of a haptic data visualization system for people with visual impairments.

Data visualization is a technique used to explore real or simulated data by representing it in a form more suitable for comprehension. This form is usually visual since vision provides a means to perceive large quantities of spatial information quickly. However, people who are blind or visually impaired must rely on other senses to accomplish this perception. Haptic interface technology makes digital information tangible, which can provide an additional medium for data exploration and analysis. Unfortunately, the amount of information that can be perceived through a haptic interface is considerably less than that which can be perceived through vision, so a haptic environment must be enhanced to aid the comprehension of the display. This enhancement includes speech output and the addition of object properties such as friction and texture. Textures are generated which can be modified according to a characteristic or property of the object to which it is applied. For example, textures can be used as an analog to color in graphical displays to highlight variations in data. Taking all of these factors into account, methods for representing various forms of data are presented here with the goal of providing a haptic visualization system without the need for a visual component. The data forms considered include one-, two-, and three-dimensional (1-D, 2-D, and 3-D) data which can be rendered using points, lines, surfaces, or vector fields similar to traditional graphical displays. The end result is a system for the haptic display of these common data sets which is accessible for people with visual impairments.     

Principles and methods for automatic and semi-automatic tissue segmentation in MRI data

The development of magnetic resonance imaging (MRI) revolutionized both the medical and scientific worlds. A large variety of MRI options have generated a huge amount of image data to interpret. The investigation of a specific tissue in 3D or 4D MR images can be facilitated by image processing techniques, such as segmentation and registration. In this work, we provide a brief review of the principles and methods that are commonly applied to achieve superior tissue segmentation results in MRI. The impacts of MR image acquisition on segmentation outcome and the principles of selecting and exploiting segmentation techniques tailored for specific tissue identification tasks are discussed. In the end, two exemplary applications, breast and fibroglandular tissue segmentation in MRI and myocardium segmentation in short-axis cine and real-time MRI, are discussed to explain the typical challenges that can be posed in practical segmentation tasks in MRI data. The corresponding solutions that are adopted to deal with these challenges of the two practical segmentation tasks are thoroughly reviewed.     

智能配网调度支持系统设计与应用(二)

针对配电网中生产管理信息的“不全面、不一致、不及时、不准确”以及受制于GIS的瓶颈问题,设计了一套基于可视化技术的配电网调度支持系统.在以调度员思维模式为框架、以可视化界面为功能模范、以互动计算为系统核心的系统功能设计实现的基础上,对系统的操作界面包括基本图形显示、接线图管理、图形功能等,以及系统数据接口方式进行了详细...     

信息运行可视化平台的设计与实现

在分析了目前青海省电力公司信息运行工作对可视化监控及经营成果展示实际需求的基础上,根据信息系统运行监控的特点,设计并实现了可视化平台。平台采用了组件化的设计思路和面向对象技术,以Java作为后台服务开发工具,以微软最新的WPF作为前台界面展现工具,数据集成接口开发遵循SOA规范,通过配合大屏幕展现,可实现信息、通信系统运行状况实时监控并兼顾公司经营成果展示,对提高公司信息、通信运行管理水平有很大的现实意义。