Image storage,transmission and manipulation

Summary

Medical imaging is the study of human functions and anatomy through pictorial information. During the past 15 years all new medical imaging modalities introduced are digital-based systems. Firstly the concept of digital imaging, the meaning of spatial and density resolutions, and signal-to-noise ratio is reviewed. Based on these definitions, the current technology in image storage and transmission is discussed including the magnetic disk, the parallel transfer disk, the optical disk, Ethernet, the fibre distributed data interface (FDDI), and Ultranet.

Among many image manipulation functions, two simple types which are commonly used in clinical applications are discussed, one for visualization enhancement and the other for quantification.     

CR与普通X线摄影在诊断中的比较

目的 探讨CR在诊断中较普通X线摄影的优势。方法 50例(胸片10例：其中床旁胸片3例、小孩胸片2例，鼻骨8例，腹部平片7例：其中小孩3例，脊柱15例：其中床旁1例，四肢关节10例：其中床旁1例、小孩1例)行CR检查．所有病例同时行普通X线检查。结果 ①50例病人行CR检查时的诊断准确率高于普通X线检查。CR检查时的诊断准确率为92％．而普通X线检查时的诊断准确率为80％。CR检查时的阳性率为52％，普通X线检查时的阳性率为44％。②)CR检查的漏诊与不确定诊断率低于普通X线检查。全部病人行CR检查时无漏诊、不确定诊断病例2例．全部病人行普通X线检查时有1份漏诊．不确定诊断病例5例。③CR检查的重拍率低于普通X线检查．其中以床旁拍片与小孩拍片为甚。全部病例行CR检查时重拍1例．普通X线检查重拍5例。④2例病人做胸片检查在行CR处理时发现有肾结石，而普通X线检查显示不出来。结论 CR检查在诊断中的效果优于普通X线检查，     

Supporting Adaption to Body Image Disruption

Nurses in hospitals, rehabilitation, and community settings often provide care for clients who are adjusting to significant alterations in their physical appearance or function. A grounded theory of reimaging provides guidelines for understanding the process of adaptation and the implications for supportive care after body image disruptions.     

脊椎图像分割和配准的研究进展

脊柱结构非常复杂,位置极其重要,脊柱手术不仅手术风险性大,而且对医生熟练程度要求高。利用图像导航系统进行脊柱外科手术能够降低风险、减少术后并发症,而脊柱图像分割和配准是其中的关键步骤。本文归纳总结脊柱图像分割和配准方法并对其进行分类,并在分析现行方法基础上指出这一领域存在的不足,并展望未来的发展。     

医学图像融合技术及其应用

医学图像融合技术在临床诊断和治疗、计算机辅助诊断、远程医疗、放射治疗及制定手术计划等方面有着广泛的应用前景,本文详细介绍了医学图像融合的意义、融合技术的内涵、分类、主要方法和步骤以及应用发展概况,并在此基础上分析了医学图像融合的技术难点和目前亟需解决的问题,最后对医学图像融合技术的发展前景作了展望.     

Tumor Malignancy Detection Using Histopathology Imaging

Image segmentation and classification in the biomedical imaging field has high worth in cancer diagnosis and grading. The proposed method classifies the images based on a combination of handcrafted features and shape features using bag of visual words (BoW). The multistage segmentation technique to localize the nuclei in histopathology images includes the stain decomposition and histogram equalization to highlight the nucleus region, followed by the nuclei key point extraction using fast radial symmetry transform, normalized graph cut based on the nuclei region estimation, and nuclei boundary estimation using modified gradient. Subsequently, features from localized regions termed as handcrafted features and the shape features using BoW are extracted for classification. The experiments are performed using both the handcrafted features and BoW to take the advantages of both local nuclei features and globally spatial features. The simulation is performed on the Bisque and BreakHis data sets (with corresponding average accuracies of 93.87% and 96.96%, respectively) and confirms better diagnosis performance using the proposed method.     

慢性肾病的彩色多普勒研究

目的观察慢性肾病患者的彩色(CDFI)及能量多普勒血流图(CDPI)变化并与病理结果进行对照分析.材料与方法分别对临床确诊并经肾穿刺活检病理证实的80例肾实质弥漫性疾病患者及40例正常对照进行二维超声,观察肾实质回声情况,CDFI、CDPI显示肾血流灌注状况并计算肾血管阻力指数(RI).结果病变在肾间质的肾脏RI为0.70±0.02,在肾小球的RI为0.53±0.05,在肾血管的RI为0.76±0.02,三者间有显著差异.肾脏回声异常与否在RI间元显著差异.CDPI在肾功能的不同时期可表现为充满型、边缘缺损型、星点型及无血流型.结论影响多普勒信号的主要因素在于肾脏原发病的位置,小管间质及血管疾病其RI升高,病变局限于肾小球的RI正常.CDPI对判断肾功能状态及预后估计有一定意义.     

计算机图像处理技术在舌像特征提取中的应用

本文综合运用数字图像处理和计算机视觉技术,应用VC++开发环境和Matlab程序设计语言,以舌像为具体研究对象,通过舌形、颜色、边缘、纹理等表面特征的提取与分析,研究计算机图像处理技术在舌像特征提取中的应用.开发的软件功能齐全,界面友好,使用方便.本文为中医舌像的模式识别提供了特征数据,是下一步对舌像进行识别的基础.     

Visual display technology for endoscopic surgery

Summary

Recent technical developments have substantially changed operating equipment for laparoscopic surgery. New devices offer a variety of functions, but also increase technical complexity in the operating room (OR), as well as the overall costs for equipment. In most cases, these are multiple, discrete, single-function devices which cannot be handled and controlled entirely and directly by the surgeon. The ‘OR Server’ is a new approach to the concept of an integrated single-unit workstation for minimally invasive surgery. It has been designed by industrial designers, in cooperation with surgeons and engineers, to incorporate the idea of ‘maximum use and minimum overall cost at maximum ergonomics’. It offers direct adjustment and control of: pressure-controlled gas insufflation; infinitely variable high frequency surgery; suction and temperature-controlled irrigation; electronically-controlled light source; on-demand video documentation and transmission into lecture rooms; telecommunication; data and device networks [1]. The clearly arranged all-in-one device aims to reduce the surgeon's stress by directly providing all relevant information and control. A central user interface offers consistent, coherent handling and simplifies the ‘devices’ use, cutting down both surgery time and error rates (and therefore saving money). The ‘OR Server’ presents itself as an integral part of a future ‘fully networked’ surgery, allowing all surgical data to be used for documentation, simulation, training, remote applications, pre-programming and constant improvement of all procedures.     

B超在尿路体外震波碎石术中的应用

本文对498例尿路结石体外震波碎石术行B超定位观察,可见碎石声像有摊长型、扩散型和扩大型并比较碎石疗效有显著差别。各组结石碎石疗效经统计学分析优劣势有明显差异。从而提出在尿路结石碎石术中的B超能准确定位、有效地选择治疗冲击波途径及全程观察判断碎石程度,B超作碎石术前疗效预计及适应症筛选有其显像学优点。认为B超作为体外震波碎石的定位观察系统更利于碎石治疗的推广。     

A 3D computer graphics approach to brachytherapy planning

Intravascular brachytherapy (IVB) can significantly reduce the risk of restenosis after interventional treatment of stenotic arteries, if planned and applied correctly. In order to facilitate computer-based IVB planning, a three-dimensional reconstruction of the stenotic artery based on intravascular ultrasound (IVUS) sequences is desirable. For this purpose, the frames of the IVUS sequence are properly aligned in space, possible gaps inbetween the IVUS frames are filled by interpolation with radial basis functions known from scattered data interpolation. The alignment procedure uses additional information which is obtained from biplane X-ray angiography performed simultaneously during the capturing of the IVUS sequence. After IVUS images and biplane angiography data are acquired from the patient, the vessel-wall borders and the IVUS catheter are detected by an active contour algorithm. Next, the twist (relative orientation) between adjacent IVUS frames is determined by a sequential triangulation method. The absolute orientation of each frame is established by a stochastic analysis based on anatomical landmarks. Finally, the reconstructed 3D vessel model is visualized by methods of combined volume and polygon rendering. The reconstruction is then used for the computation of the radiation-distribution within the tissue, emitted from a beta-radiation source. All these steps are performed during the percutaneous intervention.     

基于K-Means及K-NN的磁共振颅脑图像分割初探

目的对K-均值聚类(K-Means)和K-最近邻规则(K-NN)方法在MR颅脑图像分割中的应用进行研究,分析二者优缺点并提出改进。方法利用K-Means算法和K-NN算法对脑组织进行分割。为了减少人脑的劳动使算法自动进行,提出使用K-Means方法提取K-NN方法的训练样本。结果 K-Means与K-NN及改良后的K-NN算法(KMN)能很好地从大脑结构中分割白质(white matter,WM)、灰质(grey matter,GM)和脑脊液(cerebrospinal fluid,CSF)。结论实验表明K-Means与K-NN能快速有效地分割脑组织,改进后的K-NN方法减少了人工参与,并能获得较好的分割效果。     

Self-concept and body-image disturbance: Which self-beliefs predict body size overestimation?

Two studies investigated the relation between self-concept and body-image disturbance in selected female undergraduates. In each study, high- and low-body-shape-concerned women completed a set of self-concept assessments, including both appearance-specific questions and a measure of general self-discrepancies. One month later, they participated in an experiment in which they made judgments comparing the sizes of body silhouettes to their own bodies. Signal detection analysis indicated that the groups differed significantly on the criterion for deciding that a silhouette was larger than their own bodies (bias) but not on the ability to accurately discriminate among silhouettes (sensitivity). Among self-concept measures, overall actual:ideal self-discrepancy was the best predictor of subjects' biases in estimating their own body sizes. We are grateful to several anonymous reviewers for their comments, critiques, and suggestions on an earlier version of this paper. Also, we thank Melissa Arnett, Brigit Campbell, Laura Green, Marey Jaskowski, Kimberly Norden, Elizabeth Sacks, and Sandy Strutt for their invaluable assistance as experimenters. The research was supported by a grant from the UW-Madison Graduate School Research Committee.     

超声图像预处理方法的改进研究

目的在对超声图像传统预处理方法进行处理后效果对比分析的基础上,提出一些改进措施。方法以超声医学影像为关键点,分析其噪声,提取噪声特征,从空间域处理技术来阐述超声医学影像的预处理方法。结果生物医学图像预处理技术是医学图像系统中最关键的技术之一,直接影响医生的正确诊断,以及后期的医学数据分析。对原始图像经过双精度处理,图像整体亮度会被拉低。变换图像窗口,选择感兴趣的灰度区域进行灰度提升,增强图像的灰度可视信息,对比未做双精度处理前的实验。结论采用新的灰度处理方法后的图像,具有平滑的边缘,清晰的细节,能更好地保留细节信息,具有一定的现实意义和实用价值。     

Ultrasonographic evaluation using the internal echo in normal and cirrhotic livers: Comparison of accuracy of gray-scale and binary black-and-white images and their intraobserver reproducibility and interobserver agreement

We attempt to determine the possibility of classifying normal and cirrhotic livers by their internal echo texture alone, without using such basic ultrasonographic information as shape and surface character of the liver. We also assessed intraobserver reproducibility and interobserver agreement obtained using this classification to ascertain the diagnostic usefulness of the method. In this evaluation, we used both regional magnified B-mode images and binary black-and-white images, both derived from conventional B-mode images obtained from 10 patients with normal livers and 10 with cirrhotic livers. These 20 echograms were randomly divided into two groups and evaluated independently on two occasions by 12 observers who used the unaided eye and took only internal echo texture into consideration. Accuracy in distinguishing between normal and cirrhotic livers ranged from 41.7 percent to 100 percent. The intraobserver correlation coefficient r1 between evaluations of the regional magnified B-mode images was 0.63, while that for the binary black-and-white images was 0.80. Agreement between the decisions of the 12 observers in the first and second evaluations of the binary black-and-white images showedk values between 0 and 1.0 for binary black-and-white images and between −0.32 and 0.29 for regional magnified B-mode images. Subjective evaluation of normal and cirrhotic livers based on internal echo texture alone was possible: intraobserver correlation was good; and unexpectedly, agreement with black-and-white images was greater than that with the regional magnified B-mode images.     

Body image: A cognitive self-schema construct?

Body image has been a useful construct for understanding eating disorders. In that capacity, body image has been defined in many ways: One concept of body image is as an internalized view of one's appearance that drives behavior and influences information processing. This cognitive schema definition of body image was tested in a series of studies. Other recent studies have investigated cognitive processes with body image information, but they have focused on weight-related body image. A combination of Higgins' self-discrepancy theory and Markus' self-schema theory were used to describe a modern interpretation of body image as an internalized self-representation. Both of these theories predict specific information processing consequences of an organized cognitive representation. In turn, these consequences confirm the existence of that representation. Several studies were conducted to test a specific schema-like view of body image. In Study 1 body image schema variables were correlated with traditional measures of body image. In Study 2 subjects exposed to schema relevant contents showed information processing consequences consistent with self-representation theory. Finally, in Study 3 instructional set was shown to modify the schema activation effect. These effects give evidence of body image schema and yield limited information about the nature of that representation.Studies 1 and 2 were included in the first author's doctoral dissertation submitted in partial fulfillment of doctoral requirements, 1991. Portions of these data were also presented at the Annual Meeting of the Association for the Advancement of Behavior Therapy, 1992.     

医学影像存档与通讯系统影像诊断客户机的硬件配置对调用图像速度的影响

目的：分析影响医学影像存档与通讯系统(picture archiving and communication system，PACS)影像诊断客户机调用图像速度的关键因素，以选择适合的硬件配置方案。材料与方法：通过调换两组不同档次的中央处理器(central processing unit，CPu)、随机存储器(内存，random access memory，RAM)、显卡、硬盘和主板来测试计算机各部分配件对速度的影响。结果：cPu和主板对速度的影响最大，硬盘和内存对速度的影响较小，显卡对速度没有影响。结论：在配置客户机时应将主要资金投入到cPu和主板上，硬盘和内存只要容量够用即可，显卡则不用投入过多资金。     

Statistical image reconstruction methods for randoms-precorrected PET scans

Positron emission tomography (PET) measurements are usually precorrected for accidental coincidence events by real-time subtraction of the delayed-window coincidences. Randoms subtraction compensates on average for accidental coincidences but destroys the Poisson statistics. We propose and analyze two new approximations to the exact log-likelihood of the precorrected measurements, one based on a 'shifted Poisson' model, the other based on saddle-point approximations to the measurement of probability mass function (PMF). The methods apply to both emission and transmission tomography; however, in this paper we focus on transmission tomography. We compare the new models to conventional data-weighted least-squares (WLS) and conventional maximum-likelihood methods [based on the ordinary Poisson (OP) model] using simulations and analytic approximations. The results demonstrate that the proposed methods avoid the systematic bias of the WLS method, and lead to significantly lower variance than the conventional OP method. The saddle-point method provides a more accurate approximation to the exact log-likelihood than the WLS, OP and shifted Poisson alternatives. However, the simpler shifted Poisson method yielded comparable bias-variance performance to the saddle-point method in the simulations. The new methods offer improved image reconstruction in PET through more realistic statistical modeling, yet with negligible increase in computation time over the conventional OP method.