Simultaneous query and retrieve from multiple DICOM image archives using a proxy server

PURPOSE: DICOM clients could not access more than one archive simultaneously in the previous PACS systems. We developed a proxy server which makes it possible for clients to query and retrieve images from multivendor DICOM archives simultaneously. METHODS: We used a Web server that supports the DICOM query and retrieve(Q/R) service class as a proxy server. This system consisted of two DICOM servers and six DICOM clients of different vendors in the Radiology Department. Through Web browsers on the clients, requests for Q/R were transmitted to the proxy server by hypertext transfer protocol. The proxy server communicated with DICOM servers by DICOM Q/R Service Class(C-FIND, C-MOVE), and then DICOM servers directly transmitted images to DICOM clients by DICOM Storage Service Class(C-STORE). RESULTS: DICOM clients could transmit Q/R requests to two DICOM servers simultaneously via the proxy server and receive requested images promptly. Confirmation of conformance among the proxy server, DICOM archives, and DICOM clients became much easier than previously. CONCLUSION: A Web server working as a proxy server of the DICOM Q/R Service Class is an effective solution for allowing DICOM clients to communicate with multiple DICOM archives.     

Evaluation of radiological workstations and web-browser-based image distribution clients for a PACS project in hands-on workshops

The methodology and outcome of a hands-on workshop for the evaluation of PACS (picture archiving and communication system) software for a multihospital PACS project are described. The following radiological workstations and web-browser-based image distribution software clients were evaluated as part of a multistep evaluation of PACS vendors in March 2001: Impax DS 3000 V 4.1/Impax Web1000 (Agfa-Gevaert, Mortsel, Belgium); PathSpeed V 8.0/PathSpeed Web (GE Medical Systems, Milwaukee, Wis., USA); ID Report/ID Web (Image Devices, Idstein, Germany); EasyVision DX/EasyWeb (Philips Medical Systems, Eindhoven, Netherlands); and MagicView 1000 VB33a/MagicWeb (Siemens Medical Systems, Erlangen, Germany). A set of anonymized DICOM test data was provided to enable direct image comparison. Radiologists (n=44) evaluated the radiological workstations and nonradiologists (n=53) evaluated the image distribution software clients using different questionnaires. One vendor was not able to import the provided DICOM data set. Another vendor had problems in displaying imported cross-sectional studies in the correct stack order. Three vendors (Agfa-Gevaert, GE, Philips) presented server-client solutions with web access. Two (Siemens, Image Devices) presented stand-alone solutions. The highest scores in the class of radiological workstations were achieved by ID Report from Image Devices (p<0.005). In the class of image distribution clients, the differences were statistically not significant. Questionnaire-based evaluation was shown to be useful for guaranteeing systematic assessment. The workshop was a great success in raising interest in the PACS project in a large group of future clinical users. The methodology used in the present study may be useful for other hospitals evaluating PACS.     

Distributing medical images with internet technologies: a DICOM web server and a DICOM java viewer.

With the advent of filmless radiology, it becomes important to be able to distribute radiologic images digitally throughout an entire hospital. A new approach based on World Wide Web technologies was developed to accomplish this objective. This approach involves a Web server that allows the query and retrieval of images stored in a Digital Imaging and Communications in Medicine (DICOM) archive. The images can be viewed inside a Web browser with use of a small Java program known as the DICOM Java Viewer, which is executed inside the browser. The system offers several advantages over more traditional picture archiving and communication systems (PACS): It is easy to install and maintain, is platform independent, allows images to be manipulated and displayed efficiently, and is easy to integrate with existing systems that are already making use of Web technologies. The system is user-friendly and can easily be used from outside the hospital if a security policy is in place. The simplicity and flexibility of Internet technologies makes them highly preferable to the more complex PACS workstations. The system works well, especially with magnetic resonance and computed tomographic images, and can help improve and simplify interdepartmental relationships in a filmless hospital environment.     

Integration of a multimedia teaching and reference database in a PACS environment.

In one radiology department, a computerized authoring and editing environment was developed and integrated with the picture archiving and communication systems (PACS) for creation of image-based electronic teaching files to replace a collection of printed film images. This multimedia database and authoring environment allows physicians to create reference databases for teaching and research directly from clinical cases being reviewed on PACS diagnostic workstations. The database engine allows users to generate stand-alone CD-ROMs (compact disks, read-only memory) and World Wide Web-based teaching files. The system is fully compliant with the Digital Imaging and Communications in Medicine (DICOM) standard and supports a large number of standard multimedia image file formats. The focus of the development was on convenience and ease of use of a generic system adaptable to all users. The software was integrated on the PACS workstations to allow users to add new cases to the database at any time and anywhere in the department. A pilot system was implemented in clinical operation, with a central server and several client units.     

医学影像学信息系统工作站配置方案的探讨

目的：探讨适合国情的医学影像学信息系统工作站配置方案及实现方式。方法：工作站逻辑上分别医学影像存储与传输系统（PACS）工作站和放射学信息系统（RIS）工作站。PACS工作站包括CT和MR影像诊断、常规X线影像诊断，以及高分辨灰阶显示等3类工作站组成；RIS工作站则根据其用途分为诊断报告、登录、报告打印与分发、管理等多种功能类别。结果：影像诊断报告工作站采用单机双屏构型，物理地集成PACS和RIS的影像诊断过程的操作。CT、MR等低像素影像诊断过程配置对角线17in(1in=2.54cm）彩色显示顺作为操作界面，常规X线影像诊断操作则采用21i彩色或灰阶肖像式显示器配置，对于未涉及影像操作的工作站类型，如IRS登录、报告分发、管理等，全部采用普通PC机实现。结论：满足医学影像诊断的基本需求并符合节约投资的要求是进行医学影像学信息系统工作站规划所遵循的基本原则，单机双显配置可以成为医学影像学诊断工作站构型设计的首选方案。     

WINDOWS环境下DICOM医学图像显示方法的初步研究

目的：探讨WINDOWS环境下显示DICOM格式图像的方法.方法：通过自编程序读出DICOM图像的相关数据,实现DICOM格式图像在WINDOWS下的显示.结果：选取MR、CT、DR等不同模态的DICOM图像进行实验,均可正确显示.结论：针对DICOM图像文件存储的格式编制的程序,实现了DICOM图像文件的读取显示.本程序运行于WINDOWS环境,不依赖于具体的DICOM工作站,便于科研教学使用.     

医学影像存档与通讯系统的开发与初步应用

目的 通过组建简便医学影像存档与通讯系统（ｐｉｃｔｕｒｅ ａｒｃｈｉｖｉｎｇ ａｎｄ ｃｏｍｍｕｎｉｃａｔｉｏｎ ｓｙｓｔｅｍｓ,ＰＡＣＳ）实现影像诊断设备的网络化,诊断报告书写计算机化,标准化。方法 ＣＴ,ＭＲＩ和Ｓｕｎ Ａｄｖａｎｔａｇｅ Ｗｉｎｄｏｗｓ１２．０工作站连接成医学数字影像传输（ＤＩＣＯＭ）网络;ＤＩＣＯＭ 与各图像浏览及诊断报告书写终连接成以太网网络;二者再通过集线器连接成ＰＡＣ     

Design and development of a secure DICOM-Network Attached Server

It is not easy to connect a Web-based server with an existing DICOM server, and using a Web-based server on the Internet has risks. In this study, we designed and developed a secure DICOM-Network Attached Server (DICOM-NAS) through which the DICOM server in a hospital LAN was connected to the Internet. After receiving a client's image export request, the DICOM-NAS sent it to the DICOM server using the DICOM protocol. The server then provided DICOM images to the DICOM-NAS, which transferred them to the client, using HTTP. The DICOM-NAS plays an important role between the DICOM protocol and HTTP, and stores the requested images only temporarily. The DICOM server keeps all of the original DICOM images. If an unauthorized user attempts to access the DICOM-NAS, medical images cannot be accessed because images are not stored in the DICOM-NAS. Furthermore, the DICOM-NAS has features related to reporting and MPR. Therefore, the DICOM-NAS does not require a large storage capacity, but can greatly improve information security.     

Detection rates in pediatric diagnostic imaging: A picture archive and communication system compared with a web-based imaging system.

OBJECTIVE: This prospective study assesses whether there are differences in accuracy of interpretation of diagnostic images among users of a picture archive and communication system (PACS) diagnostic workstation, compared with a less costly Web-based imaging system on a personal computer (PC) with a high-resolution monitor. METHODS: One hundred consecutive pediatric chest or abdomen and skeletal X-rays were selected from hospital inpatient and outpatient studies over a 5-month interval. They were classified as normal (n = 32), obviously abnormal (n = 33), or having subtle abnormal findings (n = 35) by 2 senior radiologists who reached a consensus for each individual case. Subsequently, 5 raters with varying degrees of experience independently viewed and interpreted the cases as normal or abnormal. Raters viewed each image 1 month apart on a PACS and on the Web-based PC imaging system. McNemar tests were used to compare accuracy of interpretation across both imaging systems. Confidence intervals (CIs) were calculated for differences in the proportion assessed incorrectly on the PACS, compared with the Web-based PC imaging system. RESULTS: There was no relation between accuracy of detection and the system used to evaluate X-ray images (P = 0.92). The total percentage of incorrect interpretations on the Web-based PC imaging system was 23.2%, compared with 23.6% on the PACS (P = 0.92). For all raters combined, the overall difference in proportion assessed incorrectly on the PACS, compared with the PC system, was not significant at 0.4% (95%CI, -3.5% to 4.3%). CONCLUSION: The high-resolution Web-based imaging system via PC is an adequate alternative to a PACS clinical workstation. Accordingly, the provision of a more extensive network of workstations throughout the hospital setting could have potentially significant cost savings.     

PACS系统的应用体会

目的：介绍我院影像医学存档与通讯系统（ＰＡＣＳ）应用的经验。材料与方法：将所有Ｂ超、ＣＴ、Ｘ线机和一台ＩＢＭ服务器、四台奔腾Ⅱ档次的工作站及惠普光盘塔连接成医学数字影像传输（ＤＩＣＯＭ）网络;ＤＩＣＯＭ服务器与各种图像浏览终端羞以太网络;通过ＨＵＢ连接成ＰＡＣＳ系统。结果：将常规放射图像的模拟信号通过数字转换器转换为数字信号后,与ＣＴ等数字成像系统的数字信号一并输入光盘塔,并进行诊断。将数字图像和诊断报告一起舆到医院各个图像浏览终端,使其可通过ＷＥＢ界面系统及咨询平台进行查询。ＰＡＣＳ投入使用２年来,效果良好。结论：ＰＡＣＳ的应用明显提高了放射科及相关科室的工作效率,方便了工作、教学、科研和会诊。     

Wunsch und Wirklichkeit bei der Installation einer abteilungsübergreifenden Bild- und Befunddistribution

PROBLEM: This report describes the problems that can occur in the representation of the radiological workplace in a digital environment. On one hand the radiologist can sometimes access good equipment in "stand-alone" surroundings (CT, laser printer, workstations,...); on the other hand, the existing insufficient communication between different components is only rarely qualified to support the radiological workflow. This unsatisfactory framework handicaps the required clinic-wide distribution of radiological information. METHODS: From the beginning we defined user groups requiring different radiological data closely associated with specific hard- and software: The radiological workstation in the department for reporting and image processing. The demonstration workstation in wards/outpatient departments for clinicians involved in treatment. Standard PCs with access to the digital medical document for clinicians involved in treatment. At all workstations the medical as well as the legal unity of digital radiological images and the corresponding report is ensured. RESULTS: Only the first two user groups have unrestricted access to the RIS database and to the PACS archive. We have decided that the RIS should be the master of the RIS/PACS-System. For an effective master/slave relationship between RIS and PACS archive and PACS workstations we suggest to mark images and/or series of images. CONCLUSION: The third user group depends on the information exported by the radiologist from PACS. After the report is written and signed by the radiologist, the digital report is transferred from the RIS to the HIS. The report is automatically attached to these images. Authorized personnel at the wards and outpatient are able to read the combination of validated report and exported radiological images as part of the digital medical record with an intranet browser on standard PCs.     

CAD-PACS integration tool kit based on DICOM secondary capture, structured report and IHE workflow profiles.

Computer aided diagnosis/detection (CAD) goes beyond subjective visual assessment of clinical images providing quantitative computer analysis of the image content, and can greatly improve clinical diagnostic outcome. Many CAD applications, including commercial and research CAD, have been developed with no ability to integrate the CAD results with a clinical picture archiving and communication system (PACS). This has hindered the extensive use of CAD for maximum benefit within a clinical environment. In this paper, we present a CAD-PACS integration toolkit that integrates CAD results with a clinical PACS. The toolkit is a software package with two versions: DICOM (digital imaging and communications in medicine)-SC (secondary capture) and DICOM-IHE (Integrating the Healthcare Enterprise). The former uses the DICOM secondary capture object model to convert the screen shot of the CAD results to a DICOM image file for PACS workstations to display, while the latter converts the CAD results to a DICOM structured report (SR) based on IHE Workflow Profiles. The DICOM-SC method is simple and easy to be implemented without ability for further data mining of CAD results, while the DICOM-IHE can be used for data mining of CAD results in the future but more complicated to implement than the DICOM-SC method.     

Development of a low-cost DICOM-server for teaching and research purposes

PURPOSE: This paper describes our experience in developing a DICOM (Digital Imaging and Communications in Medicine) server based on widely available personal computers enabling to use X-ray digital images for teaching and scientific purposes. MATERIALS AND METHODS: The system is based on a DICOM server running on a widely used personal computer. The selected DICOM images are collected directly from the radiological equipment or from a dedicated 3D image processing workstation through a LAN connection and converted into one of the standard formats (JPEG or GIF) to allow their direct importing into multimedia presentations for teaching or scientific purposes. RESULTS: This system allows fast and easy collection of radiological images in DICOM format directly from the diagnostic equipment or from the graphical workstation. These images may be used for scientific and teaching presentations without loss of image quality and colour characteristics in 3D images as there is no off-line acquisition process. CONCLUSIONS: The extensive possibilities of implement the system described on widely used PCs makes the system extremely versatile and facilitates the preparation of teaching material and scientific publications.     

Integration of computer assisted bone age assessment with clinical PACS.

Computer assisted bone age assessment (BAA) integrated with a clinical PACS is described. The image analysis is performed on a DICOM compliant workstation able to accept images from a PACS server or directly from an image modality (digital radiography or film scanner). Images can be processed in two modes. If the image is acquired from a normally developed subject, it can be added to the digital hand atlas. An image may also be subjected only to a diagnostic analysis for the BAA without archiving the features in the database. The image analysis is performed in three steps. A location of six region of interest is followed by their segmentation and feature extraction. The features analysis results in retrieving the closest image match from the standard database. Based on currently analyzed image data in the hand atlas, the standard deviation of the assessment bone age does not exceed 1 yr of age.     

Success with Web-based image access

The University of Mississippi Medical Center in Jackson, Miss., is the only medical school in the state. We performed 235,000 procedures in the 2001-02 fiscal year. All imaging services within the radiology department are networked to a PACS and are filmless. The elimination of film required that we decentralize our traditional file room to allow easy access to our radiology network across the campus. In our facility, there are three levels of image access: Diagnostic Quality, Review Quality and Web Access. Diagnostic Quality requires top-of-the-line workstations and monitors and is the most expensive. Review Quality workstations represent some savings over Diagnostic and are used in the ICU, orthopedics and surgery. Web Access appears to satisfy most areas outside the main diagnostic department. The account set-up procedure is simple because it uses our intranet email system. Images are easily pasted into presentation applications for articles and conferences. However, the main advantage of Web Access is the low cost. The downside of Web Access is that the images are for review only and are limited by the quality of the monitor in use. It is also somewhat cumbersome to retrieve old or comparison images via this method. The Web only holds approximately 45 days of the most recent images, therefore older studies may not be available. The deployment of this Web-based service has aided in our efforts to reduce the amount of film we print and has also been beneficial in improving patient care through faster service.     

Integrating postprocessed functional MR images with picture archiving and communication systems

We describe a method of converting postprocessed functional MR images to the Digital Imaging and Communications in Medicine (DICOM) standard and sending these DICOM images directly into any picture archiving and communication system (PACS) or stand-alone DICOM database. This method provides system-wide access and archiving of previously research-only applications, it permits the clinical review of postprocessed data on DICOM-compliant workstations, and it can be used to move functional MR data onto intraoperative neuronavigational workstations for surgical guidance. The procedure can be used with any MR postprocessed dataset, and it can be extended to other imaging modalities.     

A practical approach to soft-copy display consistency for PC-based review workstations

The use of non-permanent, digital image display, i.e. soft-copy display, is increasing within hospitals due to the growth in the use of digital modalities and picture archiving and communication systems (PACS). Non-dedicated image review using standard PCs is being employed as a cost-effective method of image access. These workstations do not have specialized display systems and are likely to suffer from inconsistent image presentation. The Digital Imaging and Communications in Medicine (DICOM) Working Group 11 has developed a display function standard (part 14) to standardize the display of grey scale images. Although this standard is starting to be adopted by manufacturers of proprietary reporting systems it is not easily applied to the existing number of non-dedicated, PC-based review systems. The aim of this work was to investigate whether display consistency could be achieved simply and reproducibly on these systems, outside of the DICOM standard: part 14, by adjusting monitor brightness and contrast settings and using the Society of Motion Picture and Television Engineers (SMPTE) digital test pattern. The study showed that by adjusting the brightness and contrast settings alone it was possible to approximate the display characteristic curves to the grey scale standard display function (GSDF) defined in the DICOM standard: part 14, but only at unacceptably low luminances. Intradisplay and interdisplay consistency could be achieved using a simple monitor set-up procedure and the SMPTE test pattern.     

The digital imaging workstation

Picture archiving and communication systems (PACS) are expected to convert film-based radiology into a computer-based digital environment, with associated cost savings and improved physician communication. The digital workstation will be used by physicians to display these "soft-copy" images; however, difficult technical challenges must be met for the workstation to compete successfully with the familiar viewbox. Issues relating to image perception and the impact on physicians' practice must be carefully considered. The spatial and contrast resolutions required vary according to imaging modality, type of procedure, and class of user. Rule-based software allows simple physician interaction and speeds image display. A consensus appears to be emerging concerning the requirements for the PACS workstation. Standards such as the American College of Radiology/National Electrical Manufacturers' Association Digital Imaging and Communication Standard are facilitating commercial applications. Yet much careful study is needed before PACS workstations will be fully integrated into radiology departments.