PACS pitfalls are mostly created from human error, whereas bottlenecks are due to imperfect design in either the PACS or image acquisition devices. These drawbacks can only be realized through accumulated clinical experience. Pitfalls due to human error are often initiated at imaging acquisition devices and at workstations. Three major errors at the acquisition devices are entering wrong input parameters, stopping an image transmission process improperly, and incorrect patient positioning. The error occurring most often at the workstation happens when the user enters too many key strokes or clicks the mouse too often before the workstation can respond. Other pitfalls at the workstation unrelated to human error are missing location markers in a CT or MR scout view, images displayed with unsuitable look-up-tables, and white boarders in CR images due to x-ray collimation. Pitfalls created due to human intervention can be minimized by a better quality assurance program and periodic in-service training, and by interfacing image acquisition devices to the HIS/RIS. Bottlenecks affecting the PACS operation include network contention; CR, CT, and MR images stacked up at acquisition devices; slow response from workstations; and long delays for image retrieval from the long term archive. Bottlenecks can be alleviated by improving the system architecture, re- configuring the networks, and streamlining operational procedures through a gradual understanding of the clinical environment. We have identified most of the pitfalls and bottlenecks discussed above in our hospital-integrated PACS based on the past two years of clinical experience. This paper categorizes some of these problems, illustrates their effect on PACS operations, and suggests methods for circumventing them.

The technology for building workstations suitable for the display of most medical images has existed for almost a decade. Yet the diagnostic interpretation process has not shifted form film to such workstations in early as large numbers as had been predicted. While, in a large part, this is due to the high costs for acquisition of picture archiving and communications system equipment, there is also the aspect of physician acceptance. Since the workstation serves as the primary system-to-person interface, an examination of the way in which workstations are designed and the way in which radiologists actually work yields some insight into the relative lack of penetration of workstations into the diagnostic image interpretation task.

The Baltimore Veterans Affairs Medical Center relocated onto the campus ofthe University of Maryland at Baltimore campus and opened in January 1993. Although the original bed capacity was 300, the hospital is currently operating approximately 200 beds. The imaging department currently performs approximately 60,000 examinations per year (up from 34,000 in 1993). Both the hospital and radiology departments were designed for digital rather than conventional imaging. The Picture Archival and Communication System (PACS) has been in operation for three and a halfyears. Radiologists have been reading imaging studies in a "soft-copy" mode using computer workstations for approximately 3 years. One hundred percent ofthe imaging studies are currently archived to the PACS. However conventional film/screen is still used as the acquisition modality for mammography and for primary interpretation of mammograms by the radiologists. These mammograms are then digitized into the PACS and are thus available for clinicians for soft-copy review.

The SNUH started a project to innovate the hospital information facilities. This project includes installation of high sped hospital network, development of new HIS, OCS, RIS and PACS. This project aims at the implementation of the first total hospital information system by seamlessly integrating these systems together. To achieve this goal, we took three-tiered systems integration approach: network level, database level, and workstation level integration. There are 3 loops of networks in SNUH: proprietary star network for host computer based HIS, Ethernet based hospital LAN for OCS and RIS, and ATM based network for PACS. They are linked together at the backbone level to allow high speed communication between these systems. We have developed special communication modules for each system that allow data interchange between different databases and computer platforms. We have also developed an integrated workstation in which both the OCS and PACS application programs run on a single computer in an integrated manner allowing the clinical users to access and display radiological images as well as textural clinical information within a single user environment. A study is in progress toward a total hospital information system in SNUH by seamlessly integrating the main hospital information resources such as HIS, OCS, PACS. With the three-tiered systems integration approach, we could successfully integrate the systems from the network level to the user application level.

Interoperability among healthcare applications goes beyond connectivity to allow components to exchange structured information, and to work together in a predictable, coordinated fashion. To facilitate building an interoperability infrastructure an Enterprise Communication Framework (ECF) was developed by the members of the Andover Working Group for Healthcare Interoperability. The ECF consists of four models, (1) the use case model, (2) the domain information model, (3) the interaction model, and (4) the message model. To realize this framework, a software component called the enterprise communicator is used. In this paper we will demonstrate the use of the framework in interoperating a PACS with a radiology information system.

Many retrievals of images from a PACS archive do not require the full spatial resolution at which the images were originally acquired. Savings in retrieval times could be realized if images were retrieved at the lower resolution required for each display need. A PACS archive was constructed wherein images are stored and may be retrieved at lower than the originally-acquired resolution. Incoming images from the modality devices are minified by successive factors of two, down to 128 X 128. A DICOM extended private attribute was defined which enabled the reduced resolution images to be retrieved with a modified DICOM move requests. The reduced resolution images can be received by a standard DICOM workstation without the need for special workstation software. Multi-resolution storage requires approximately 30 percent more space. This additional media cost is deemed acceptable for this archive, in which data are stored on low cost magnetic tape.

While they are many, one of the inhibitors to the wide spread diffusion of PACS systems has been robust, cost effective digital archive storage solutions. Moreover, an automated Nearline solution is key to a central, sharable data repository, enabling many applications such as PACS, telemedicine and teleradiology, and information warehousing and data mining for research such as patient outcome analysis. Selecting the right solution depends on a number of factors: capacity requirements, write and retrieval performance requirements, scaleability in capacity and performance, configuration architecture and flexibility, subsystem availability and reliability, security requirements, system cost, achievable benefits and cost savings, investment protection, strategic fit and more.This paper addresses many of these issues. It compares and positions optical disk and magnetic tape technologies, which are the predominant archive mediums today. Price and performance comparisons will be made at different archive capacities, plus the effect of file size on storage system throughput will be analyzed. The concept of automated migration of images from high performance, high cost storage devices to high capacity, low cost storage devices will be introduced as a viable way to minimize overall storage costs for an archive. The concept of access density will also be introduced and applied to the selection of the most cost effective archive solution.

The University of Pennsylvania Radiology Department has developed a suite of Web based applications for clinicians and radiologists to provide wide spread, cost-effective and easy access to radiological information. The Image Viewer application provides clinicians and radiologists access to all diagnostic reports and digital images performed in the last week for all Emergency Dept., Intensive Care Unit and Neuro/CT studies. Image control options including zoom/pan, rotate, flip, and window/level are all available. The image mover/viewer application gives radiologists and technologists the ability to both move studies between any DICOM Storage Class Provider (SCP) and DICOM storage class user (SCU) and to view studies from any DICOM displayed. Web server support requires integration using Perl based CGI scripts with our DICOM/PACS and the MIR/CTN for images and our IDXrad/RIS for reports. Targeted images and reports are automatically routed from the PACS and RIS for storage on the web server. All images sent to the web server are modality specific per-processed to reduce size and improve contrast. After processing, all images are stored in DICOM and GIF formats. Client support requires web browsers with JavaScript and frame support.

The Multimedia Medical Data Archive and Retrieval Server has been installed at the imaging science and information systems (ISIS) center in Georgetown University Medical Center to provide medical data archive and retrieval support for medical researchers. The medical data includes text, images, sound, and video. All medical data is keyword indexed using a database management system and placed temporarily in a staging area and then transferred to a StorageTek one terabyte tape library system with a robotic arm for permanent archive. There are two methods of interaction with the system. The first method is to use a web browser with HTML functions to perform insert, query, update, and retrieve operations. These generate dynamic SQL calls to the database and produce StorageTek API calls to the tape library. The HTML functions consist of a database, StorageTek interface, HTTP server, common gateway interface, and Java programs. The second method is to issue a DICOM store command, which is translated by the system's DICOM server to SQL calls and then produce StorageTek API calls to the tape library. The system performs as both an Internet and a DICOM server using standard protocols such as HTTP, HTML, Java, and DICOM. Users with proper authentication can log on to the server from anywhere on the Internet using a standard web browser resulting in a user-friendly, open environment, and platform independent solution for archiving multimedia medical data. It represents a complex integration of different components including a robotic tape storage system, database, user-interface, WWW protocols, and TCP/IP networking. The user will only deal with the WWW and DICOM server components of the system, the database and robotic tape library system are transparent and the user will not know that the medical data is stored on magnetic tapes. The server provides the researchers a cost-effective tool for archiving and retrieving medical data across a TCP/IP network environment. It will serve as a medium to exchange information between researchers at Georgetown University and those from other institutions.

The purpose of this presentation is to point out the issues of incorporating digital libraries (DL) technologies into picture archiving and communication systems (PACS). The DL technologies can be used to increase the knowledge content and utilities of PACS and associated medical information systems in providing a broader range of medical services. We further illustrate certain potential application areas with examples from a research prototype developed on top of the hospital-integrated PACS of UCSF.

Researchers using biomedical images have data management needs which are oriented perpendicular to clinical PACS. The image BOSS system is designed to permit researchers to organize and select images based on research topic, image metadata, and a thumbnail of the image. Image information is captured from existing images in a Unix based filesystem, stored in an object oriented database, and presented to the user in a familiar laboratory notebook metaphor. In addition, the ImageBOSS is designed to provide an extensible infrastructure for future content-based queries directly on the images.

We have developed an ATM network-based system to collect and catalogue cardio-angiogram videos from the source at a Kaiser central facility and make them available for viewing by doctors at primary care Kaiser facilities. This an example of the general problem of diagnostic data being generated at tertiary facilities, while the images, or other large data objects they produce, need to be used from a variety of other locations such as doctor's offices or local hospitals. We describe the use of a highly distributed computing and storage architecture to provide all aspects of collecting, storing, analyzing, and accessing such large data-objects in a metropolitan area ATM network. Our large data-object management system provides network interface between the object sources, the data management system and the user of the data. As the data is being stored, a cataloguing system automatically creates and stores condensed versions of the data, textural metadata and pointers to the original data. The catalogue system provides a Web-based graphical interface to the data. The user is able the view the low-resolution data with a standard Internet connection and Web browser. If high-resolution is required, a high-speed connection and special application programs can be used to view the high-resolution original data.

In this paper, Georgetown University Medical Center's (GUMC) experience with utilizing ATM technology in a telemedicine application will be presented. This application involves 3D radiation treatment planning where radiological imaging, calculation of the treatment plan, and 3D display all take place at different sites. To do this, GUMC must exchange large amounts of radiology images and data with other institutions in real time. A high speed network consisting of an ATM infrastructure and satellite links was created to connect seamlessly the three sites, GUMC, University of Hawaii, and Ohio Supercomputing Center, which are thousands of miles apart. This paper studies the performance of the ATM network between GUMC and Goddard Space Flight Center, which provides satellite service to link partners in this project. The steps required to test and evaluate the ATM system will be presented. A performance comparison between ATM and Internet-LAN connections will be featured in the presentation. In particular, the theoretical speed of 155 Mbps is hard to reach due to the lack of ATM-native protocols in the transport level of the communication structure.

Medical information systems are acquiring the ability to collect and deliver many different types of medical information. In support of the increased network demands necessitated by these expanded capabilities, asynchronous transfer mode (ATM) based networks are being deployed in medical care systems. While ATM supplies a much greater line rate than currently deployed networks, the management and standards surrounding ATM are yet to mature. This paper explores the management and control issues surrounding an ATM network supporting medical information systems, and examines how management impacts network performance and robustness. A multivendor ATM network at the BJC Health System/Washington University and the applications using the network are discussed. Performance information for specific applications is presented and analyzed. Network management's influence on application reliability is outlined. The information collected is used to show how ATM network standards and management tools influence network reliability and performance. Performance of current applications using the ATM network is discussed. Special attention is given to issues encountered in implementation of hypertext transfer protocol over ATM internet protocol (IP) communications. A classical IP ATM implementation yields greater than twenty percent higher network performance over LANE. Maximum performance for a host's suite of applications can be obtained by establishing multiple individually engineered IP links through its ATM network connection.

The Home Teleradiology Server system has been developed and installed at the Department of Radiology, Georgetown University Medical Center. The main purpose of the system is to provide a service for on-call physicians to view patients' medical images at home during off-hours. This service will reduce the overhead time required by on-call physicians to travel to the hospital, thereby increasing the efficiency of patient care and improving the total quality of the health care. Typically when a new case is conducted, the medical images generated from CT, US, and/or MRI modalities are transferred to a central server at the hospital via DICOM messages over an existing hospital network. The server has a DICOM network agent that listens to DICOM messages sent by CT, US, and MRI modalities and stores them into separate DICOM files for sending purposes. The server also has a general purpose, flexible scheduling software that can be configured to send image files to specific user(s) at certain times on any day(s) of the week. The server will then distribute the medical images to on- call physicians' homes via a high-speed modem. All file transmissions occur in the background without human interaction after the scheduling software is pre-configured accordingly. At the receiving end, the physicians' computers consist of high-end workstations that have high-speed modems to receive the medical images sent by the central server from the hospital, and DICOM compatible viewer software to view the transmitted medical images in DICOM format. A technician from the hospital, and DICOM compatible viewer software to view the transmitted medical images in DICOM format. A technician from the hospital will notify the physician(s) after all the image files have been completely sent. The physician(s) will then examine the medical images and decide if it is necessary to travel to the hospital for further examination on the patients. Overall, the Home Teleradiology system provides the on-call physicians with a cost-effective and convenient environment for viewing patients' medical images at home.

Veterans Affairs Health Care has become more decentralized with the creation of local Veteran Integrated Service Networks (VISN). The purpose of this study was to analyze the design and cost of a wide-area-network (WAN) for teleradiology in a local VISN. The Southern California VISN includes 4 large and 3 small medical centers. Only one of the 7 medical centers has an operational PACS. Data were collected on the radiologist workloads and patient and image flow within and between the 7 medical centers. This was used to estimate the size and cost of local PACS at each medical center and the need for teleradiology services. A simplified cost-analysis model was used to estimate potential cost- savings by gong filmless. Asynchronous transfer mode (ATM) technology was selected for the WAN between the medical centers. A realistic cost-savings model was developed. Cost- effectiveness of a PACS/Teleradiology system was established. Based on this model, a PACS/Teleradiology configuration for the VISN was successfully designed and partially implemented. The ATM-based WAN provides instantaneous access to PACS at each centers. Cost-analysis of the design and implementation of a PACS/teleradiology network in a VISN is possible and important when planning such system. The experience gained will serve a model for future similar projects nationwide.

The VA has developed a set of DICOM capabilities in MUMPS as an integral part of its hospital/radiology information system (HIS/RIS). DICOM is being used at the VA to transfer text and image data between the HIS/RIS to download patient study information to the commercial medical imaging equipment and to obtain digitized images from them. Our general experience with the commercial DICOM offerings that we have tested has been very favorable. These products were developed using toolkits that are quite mature, and interfacing to them has been fairly easy. The use of DICOM has the potential to reduce costs by allowing open systems solutions consisting of in-house and commercial multi-vendor offerings.

One ofthe biggest challenges in either a PACS or teleradiology environment is the requirement for accurate and rapid identification ofpatient examinations. Despite the major advances in DICOM and modality interfaces, this challenge has become an important and often frustrating issue at most PACS sites. The use of a DICOM interface does not ensure that the images will be properly matched with the correct patient or study.

One of the purposes of the DICOM standard is to promote the communication of digital image information, regardless of device manufacturer. There are numerous examples of how DICOM has made manufacturer interconnectivity a reality. While DICOM has made cross-vendor connectivity much easier to achieve, applications often depend on vendor specific information for optimal performance. Our experience in implementing DICOM's Print Management Meta SOP Classes is used to examine this concept. Indeed, DICOM has made it much easier to print to many manufacturer's imagers. However, most imagers require some unique information in order to print high quality images. Although DICOM has facilitated the simple act of printing it has also put an added burden on the developer of Print Management applications. They must supply applications that are flexible enough to provide each imager with the information necessary for diagnostic quality images. Without this type of flexibility, applications may be DICOM conformant and operational, but they will not be useful in a clinical environment.

Image communication between PACS applications and radiologic imaging equipment has always been difficult due to the proprietary communication protocols and data formats used by the individual manufacturers. With the introduction of DICOM, image communication among PACS components and radiologic imaging devices becomes feasible. We have integrated our PACS into a DICOM-compliant system that facilitates the communication of radiologic images between individual PACS components and radiologic imaging equipment. The image communication software implemented in our PACS was based on the Mallinckrodt's central test node software with several enhanced features. These features included dual network interface support, adjustable TCP buffer size, prioritizing job control, and computer host verification. The enhanced DICOM-based communication software has demonstrated a reliable yet efficient transfer for images in a PACS environment. This paper describes our implementation strategy of adapting DICOM to the UCSF PACS and the utilization of DICOM in the PACS operation.

PACS implementations require IS data for efficient operation and coherent information management. The images contributing to a radiology report in a practical multi-vendor PACS implementation may be derived from more than one DICOM study, and it is the Radiology Information System (RIS) that is responsible for the report. Flows of existing RIS-based information were studied and the required set of messages between the PACS archive and the RIS was defined. An archive providing the required functionality using standard and extended DICOM protocols was specified and acquired. The DICOM interface for the RIS was developed in-house using the M(MUMPS) programming language native to the RIS. We found that close integration of a RIS and PACS can be provided using DICOM protocols employing extensions compatible with the standard. The DICOM interfaces for textural data can be implemented in a MUMPS-based RIS without the need for an external interface 'box'.

This paper represents the discussions at the DICOM workshop for the digital imaging communications in medicine (DICOM) standard, which was orchestrated as a 'point-counterpoint' discussion. Real life issues with DICOM compatibility were posed by a user advocate to an expert panel consisting of people who participate in the DICOM standardization effort. The issue statement is described, followed by the answer by the panel.

How should hospital administrators compare the security risks of paper-based and computerized patient record systems. There is a general tendency to assume that because computer networks potentially provide broad access to hospital archives, computerized patient records are less secure than paper records and increase the risk of breaches of patient confidentiality. This assumption is ill-founded on two grounds. Reasons exist to say that the computerized patient record provides better access to patient information while enhancing overall information system security. A range of options with different trade-offs between access and security exist in both paper-based and computerized records management systems. The relative accessibility and security of any particular patient record management system depends, therefore, on administrative choice, not simply on the intrinsic features of paper or computerized information management systems.

As clinical data is more widely stored in electronic patient record management systems and transmitted over the Internet and telephone lines, it becomes more accessible and therefore more useful, but also more vulnerable. Computer systems such as PACS, telemedicine applications, and medical research networks must protect against accidental or deliberate modification, disclosure, and violation of patient confidentiality in order to be viable. Conventional wisdom in the medical field and among lawmakers legislating the use of electronic medical records suggests that, although it may improve access to information, an electronic medical record cannot be as secure as a traditional paper record. This is not the case. Information security is a well-developed field in the computer and communications industry. If medical information systems, such as PACS, telemedicine applications, and research networks, properly apply information security techniques, they can ensure the accuracy and confidentiality of their patient information and even improve the security of their data over a traditional paper record. This paper will elaborate on some of these techniques and discuss how they can be applied to medical information systems. The following systems will be used as examples for the analysis: a research laboratory at Georgetown University Medical Center, the Deployable Radiology system installed to support the US Army's peace- keeping operation in Bosnia, a kidney dialysis telemedicine system in Washington, D.C., and various experiences with implementing and integrating PACS.

Telemedical services rely on the digital transfer of large amounts of data in a short time. The acceptance of these services requires therefore new hard- and software concepts. The fast exchange of data is well performed within a high- speed ATM-based network. The fast access to the data from different platforms imposes more difficult problems, which may be divided into those relating to standardized data formats and those relating to different levels of data security across nations. For a standardized access to the formats and those relating to different levels of data security across nations. For a standardized access to the image data, a DICOM 3.0 server was implemented.IMages were converted into the DICOM 3.0 standard if necessary. The access to the server is provided by an implementation of DICOM in JAVA allowing access to the data from different platforms. Data protection measures to ensure the secure transfer of sensitive patient data are not yet solved within the DICOM concept. We investigated different schemes to protect data using the DICOM/JAVA modality with as little impact on data transfer speed as possible.

A new method for data integrity on ATM protocol is proposed. The algorithm represents image data via a new transform called the Mojette. The transform and its inverse are in order of complexity of the fast Fourier transform. An object oriented model for image and sequence are presented. The method is tested on videoendoscopic sequences. This source- channel coding avoids any additional protocol over ATM to secure data and provide real-time possibilities.

Privacy and integrity of medical records is expected by patients. This privacy and integrity is often mandated by regulations. Traditionally, the security of medical records has been based on physical lock and key. As the storage of patient record information shifts from paper to digital, new security concerns arise. Digital cryptographic methods provide solutions to many of these new concerns. In this paper we overview new security concerns, new legislation mandating secure medical records and solutions providing security.

The Imaging Science and Information Systems (ISIS) Center of the Department of Radiology at Georgetown University Medical Center recently collaborated with the US Army in developing an off-the-shelf teleradiology network for Operation Joint Endeavor, the peace-keeping mission in Bosnia-Herzegovina. The network is part of Operation Primetime III, a project to deploy advanced communications and medical equipment to provide state-of-the-art medical care to the 20,000 US troops stationed there. The network encompasses three major sites: the 212th Mobile Army Surgical Hospital (MASH) near Tuzla, Bosnia-Herzegovina; the 67th Combat Support Hospital (CSH) in Taszar, Hungary; and the Landstuhl Regional Medical Center (LRMC) in Landstuhl, Germany. Planning for the project began in January 1996, and all three sites were operational by April 1996. Since the system was deployed, computed radiography (CR) has been sued almost exclusively at the MASH and CSH for all general x-ray exams. From mid- May to September 1996, over 2700 CR images were acquired at the MASH and over 1600 at the CSH. Since there was not a radiologist a the MASH, the images were transferred to the CSH for primary diagnosis and archiving. In the same time period, over 550 patient folders were sent from the MASH to the CSH.

In cooperation with the US Army, Georgetown University Medical Center (GUMC) deployed a teleradiology network to sites in Bosnia-Herzegovina, Hungary, and Germany in early 1996. This deployment was part of Operation Primetime III, a military project to provide state-of-the-art medical care to the 20,000 US troops stationed in Bosnia-Herzegovina.In a three-month time frame from January to April 1996, the Imaging Sciences and Information Systems (ISIS) Center at GUMC worked with the Army to design, develop, and deploy a teleradiology network for the digital storage and transmission of radiology images. This paper will discuss some of the problems associated with sending large files over communications networks with significant delays such as those introduced by satellite transmissions.Radiology images of up to 10 megabytes are acquired, stored, and transmitted over the wide area network (WAN). The WAN included leased lines from Germany to Hungary and a satellite link form Germany to Bosnia-Herzegovina. The communications links provided at least a T-1 bandwidth. The satellite link introduces a round-trip delay of approximately 500 milliseconds. This type of high bandwidth, high delay network is called a long fat network. The images are transferred across this network using the Transmission Control Protocol (TCP/IP). By modifying the TCP/IP software to increase the window size, the throughput of the satellite link can be greatly improved.

The ISIS Center at Georgetown University was the systems integrator for a project to design, develop, and implement a commercial off-the-shelf teleradiology system to support the US troops in Bosnia-Herzegovina. Computed radiography (CR), computed tomography (CT), film digitization (FD), and ultrasound (US) were the modalities to connect to the network. Dry laser printing and multiple display workstations were also part of the network. All systems were integrated into this network using the Digital Imaging Communications (DICOM) 3.0 standard. The modalities communicate to the workstations using the DICOM 3.0 standard and the workstations send images to the printers and other vendors' workstations using DICOM 3.0. Among the seven DICOM implementations encountered for this project, none were connected without modification to configuration files, changes or patches by vendors, or operational changes by the user. Some problems encountered include missing or ignored required data elements, padding data values, unique study identifiers to differentiate studies and images, and the use of application entity titles. This paper will discuss multi- vendor connectivity and describe the DICOM 3.0 inconsistencies which were encountered. It will also detail the problems encountered and how they were resolved, including the operational changes which were required and software fixes.

The SNUH has started a PACS project with three main goals: to develop a fully hospital-integrated PACS, to develop a cost effective PACS using open systems architecture, and to extend PACS' role to the advanced application such as image guided surgery, multi-media assisted education and research. In order to achieve these goals, we have designed a PACS architecture which takes advantage of client-server computing, high speed communication network, computing power of up-to-date high-end PC, and advanced image compression method. We have installed ATM based communication network in radiology department and in-patient wards, and implemented DICOM compliant acquisition modules, image storage and management servers, and high resolution display workstations based on high-end PC and Microsoft Windows 95 and Windows NT operating systems. The SNUH PACS is in partial scale operation now, and will be expanded to full scale by the end of 1998.

The hospital at Brooke Army Medical Center in San Antonio, Texas has an essentially filmless radiology department. Mammography is one of the few services still using film. The radiology department at Brooke takes advantage of a very capable Lockheed Martin PACS to achieve the filmless operation. The old hospital has been replaced by a new hospital, the new Brooke Army Medical Center. As a basis for predictions of activity at new Brooke, the activities at the old Brooke Army Medical Center were examined. The heart of the PACS at Brooke is the image server with an associated database. The image server has the performance required to keep the radiologist from returning to film for diagnosis. A directly connected workstation can present a full screen of images in less than two seconds, even during the busiest hour of the day for this large hospital. In addition the database is used to organize the workflow for the radiology examinations through the hospital. Information about the activity at the new Brooke hospital is used to predict the utilization of the short term storage and the long term storage. In particular, the time that an examination will be retained on the new Brooke short term storage is measured. The Brooke medical complex generates 384.8 exams per day on a typical weekday. The number of exams on a weekend is 40 percent of the exams on the weekday. The storage required is 18.3 gigabytes per day in the short term storage of the Image Storage Unit (ISU) and 9.7 gigabytes per day in the archive. The 256 gigabytes of the ISU will hold 11.7 weeks or about 2.5 months of exams. The archive will hold four years of exams in tow jukeboxes. A working year will have an effective 300 days of equivalent weekday radiology load. By ten years from now the hospital complex can be expected to handle to load that is estimated to be about 160 percent of the current load. With the changes in the storage of disks and archive media that will have occurred by that time, the number of weeks of storage will be greater than that held now.

A PACS workstation grants to Intensive Care Unit (ICU) staff direct and convenient access to radiographic images. The special requirements of access to, and display of radiographic images in the ICU were considered in the design of a PACS workstation for the ICU. and implemented as an extension of the Image Management and Communication Systems (IMACS) network at McMaster University Medical Center. The majority of radiographic exams performed in the ICU are portable chest x-ray exams. These images are processed by Computed Radiography and immediately directed towards online storage on the ICU workstation's local disk. Our image display software interface for the workstation was specially designed for the ICU to provide patient data entry, fast thumbnail viewing of all images for the occupied beds, full resolution display, and image manipulation, all in a user- friendly graphical interface. The workstation has been in place in the ICU for 1.5 years. While there are upgrades still to be made to the computer and monitors, and changes to the workflow to be made, the workstation has established itself as a n important part of the ICU.

Surgical treatment of temporal lobe epilepsy requires the localization of the epileptogenic zone for surgical resection. Currently, clinicians utilize electroencephalography, various neuroimaging modalities, and psychological tests together to determine the location of this zone. We investigate how a multimedia neuroimaging workstation built on top of the UCSF Picture Archiving and Communication System can be used to aid surgical planning of epilepsy and related brain diseases. This usage demonstrates the ability of the workstation to retrieve image and textural data from PACS and other image sources, register multimodality images, visualize and render 3D data sets, analyze images, generate new image and text data from the analysis, and organize all data in a relational database management system.

This study examines an image navigation system designed for a digital workstation supported by a high-capacity, high performance video frame buffer. We compare the time required for mammographers to identify and assess changes in targets imbedded in digital mammograms viewed on the workstation compared to the time required for the same task on laser printed film viewed on a multiviewer. Preliminary results indicate that mammography screening studies can be analyzed as quickly on softcopy as on hardcopy. However, affordable hardware that supports this type of image navigation remains an important problem.

A review console displaying digital radiographs should automatically display the chest images in proper orientation to save radiologists' time. To accomplish this feat, the authors have developed a simple, rapid algorithm that can be implemented in hardware. Linear regression is used on two orthogonal profiles to determine the top of the image. The edge of the heart is found to make sure the image is not displayed as a mirror image. The algorithm was 90.4 percent successful on 115 chest images.

This paper presents the key post-processing algorithms for CR images used in our second generation PACS and its software implementation based on the algorithm features, fault tolerance and multilevel adaptive control, which can enable the benefits of image processing, good performance, speed and reliability.

Both computed radiography systems at our institution offer control over the tonal and spatial frequency characteristics of the images. Our radiologists considered the default processing parameters to be suboptimal for many examinations, but the range of possible combination is tremendous. Our purpose was to develop an efficient methodology for determining the optimal processing parameters to achieve the desired image appearance for specific examinations and display types.

Soft-copy display is emerging as a practical means of efficiently interpreting portable computed radiography exams. This study comparing the soft and hard-copy presentation of portable chest radiographs was undertaken to evaluate radiologist preference and confidence prior to implementing filmless soft-copy reading of portable chest radiographs. Seven radiologists with substantial previous experience interpreting portable chest radiographs directly compared 126 hard- and soft-copy presentations of computed radiography chest radiographs obtained over a two week period from a cardiac care unit. The radiologists first viewed the soft-copy on 1k X 1k monitors, using magnification and windowing tools when desired. Immediately following interpretation, a hard-copy produced from the same 2k data set and processed with identical parameters was reviewed and subjective comparisons recorded regarding the visibility and definition of lung pathology, soft tissues, bone detail and catheters. The use of magnification and windowing tools was recorded. The resulting data showed little perceived difference between the hard- and soft-copy images. The unmodified soft-copy images were considered equivalent for diagnostic purposes in regards to lung pathology in 78 percent, soft tissue 84 percent, bone detail 68 percent and catheters 76 percent. The hard-copy was more frequently considered better for bone detail and catheter visualization. The soft-copy was more frequently considered better for visualizing lung pathology and soft tissue structures. Changing the window settings and magnification comparison of images eased their concerns about the adequacy of soft-copy presentation of computed radiography chest images at least the equivalent of hard-copy for depiction of normal anatomy and pathologic features in most categories. The next step is to optimize the soft-copy display parameters for routine viewing and then for specific clinical questions.

Digital Video Fluorography (DVF) has been developed over the past fifteen years. Although much emphasis has been placed upon digital subtraction angiography (DSA) the concept has been extended to gfluoroscopic examinations. Indeed, 1024 x 1024 DVF systems are currently being marketed by all major equipment manufacturers. In spite of these developments there are many in the Radiology Community who exhibit reservations which can, on occasion, manifest as outright antagonism to this new technology.

Congenital heart disease is infrequent and often is apparent in the immediate newborn period. Accurate diagnosis delivered in real-time or near-real-time is important to provide appropriate care to avoid patient morbidity and mortality. Color-flow Doppler echocardiograms are an essential part of the diagnostic assessment of the newborn, however, few hospitals have the staff to interpret these studies appropriately. Transmission of these studies to a regional center with subspecialists will allow interpretation of the studies by physicians with expertise in this subspecialty. Transmission of these studies to a regional center with subspecialists will allow interpretation of the studies by physicians to appropriately and rapidly triage neonates with high-risk congenital heart disease. To make a teleradiology service affordable in the near future, the 73 million bit per second transmission speed must be reduced to affordable bandwidths using compression. The purpose of this study is to evaluate the impact of motion JPEG on the diagnostic quality of pediatric echocardiograms.

The goal of this project was to evaluate the overall use and effectiveness of a teleradiology system linking the Department of Radiology at the University of Arizona with a rural site 100 miles away. Workstations were installed at the referring and consulting sites with connections to al major imaging modalities. 83 percent of the time the correct type and number of images were sent to reach a diagnosis; 17 percent needed more images or had technical problems. Image quality was judged to be adequate for 85 percent of the cases. The consulting radiologists were every or somewhat confident in their decisions 88 percent of the time. Low confidence was directly related to judged image quality or number of images available. Consultation sessions lasted 7.73 min on average and 95 percent were judged to occur in a timely manner. 95 percent of the sessions were judged to be successful overall in terms of speed and diagnostic accuracy. The current teleradiology system provides a much needed service to a rural population of patients. Overall, both the consulting and referring radiologists are satisfied with the performance of the system and with their own diagnostic performance.

The technical purposes of this work were to develop improvements in the methodology for assessing the physical performance of CRT monitors and display controller systems and to explore image processing techniques to make soft- and hard-copy image quality visually similar. The clinical purpose was to determine whether, with proper image processing, soft-copy presentations of digital chest radiographs could become equivalent to hard-copy for visualizing normal and pathological features. The luminance characteristic curve, luminance uniformity, modulation transfer function, and noise power spectra of the CRT monitors as well as video waveforms of a display controller were measured. Posteroanterior and lateral chest radiographs were acquired by a dedicated thorax imaging system with a selenium detector and processed using a previously optimized algorithm for printing on film. A Laplacian pyramid filter was employed to compensate for the mid- to high-frequency contrast losses in the soft-copy presentation. Five chest radiologists directly compared the soft- and hard-copy presentations in eighteen patients with CT-proven pathologies. Based on 99 percent confidence intervals, the soft-copy images were preferred for seven of the fourteen anatomic categories and image contrast, and the hard-copy images were preferred for brightness and image granularity. There were no preferences for the depiction of pathologies, spatial resolution, and the remaining anatomic categories. After determining the physical properties of the CRT monitors, image processing operations can be defined to produce soft-copy renditions of soft-copy displays for primary diagnosis to make digital radiography more cost- effective and to encourage additional development of filmless image interpretation and management in a PACS.

Full-field direct digital mammography has many advantages over the conventional film/screen imaging detector. Among these are larger dynamic range, lower scattering noise, and the possibility of using it for telemammography applications to alleviate the shortage of expert mammographers. We are in the process of developing a full-field direct digital telemammography imaging chain to investigate its usefulness for telediagnosis, teleconsultation, and telemanagement. This paper describes the first phase of a three-year research program to set up a full-field direct digital mammography (FFDDM) imaging chain at the Breast Imaging Section connecting the University of California, San Francisco Medical Center and the Mt. Zion Hospital in the San Francisco Bay area. The chain consists of two FFDDM system, and two 2,500 line two-monitor workstations. An OC-3 155 Mbits/sec asynchronous transfer mode (ATM) communication network is used to connect the FFDDM and the two workstations. The FFDDM is based on a slot scan CCD detector which can image a full breast with 3,100 X 3,870 pixels, and produce a direct digital image with 50 micron pixel size. Preliminary results of the FFDDM demonstrate that it has a greater dynamic range and lower detector noise than that of a film-screen detector, and that the scattered radiation is reduced without using a grid. However, the spatial resolution is less than that of the conventional screen/film system. The 2K workstation can display simultaneously any two or four full-view mammographic images by either scrolling or subsampling on the two monitors. Display of an image takes about 1.5 seconds from the RAID disks. The ATM can transmit a 32 Mbyte digital mammogram from the FFDDM to the workstation in 3-4 seconds.

The authors have been operating an ultrasound miniPACS for approximately two years. In the last six months, the system was more than doubled in size with inclusion of a teleradiology component and connection to PACS hardware from other vendors. This paper presents the engineering, operational, and clinical challenges posed by this integration and the logistical and systems approaches to meeting those challenges.

Evaluation of radiologist and non-radiologist physician acceptance of computed radiography (CR) as an alternative to film-based radiography in an emergency department (ED) is performed. All emergency department radiographs are performed using photostimulable phosphor plates and rad by a computed radiography laser reader placed in the former emergency department darkroom. Soft copy images are simultaneously transmitted to high- and medium-resolution dual-monitor display stations located in radiology and ED reading rooms respectively. The on-call radiologist is automatically paged by the Radiology Information System (RIS) upon exam completion, to read the new ED imaging study. Patient demographic information including relevant clinical history is conveyed to the radiologist via the RIS. A 'wet read' preliminary radiology report is immediately transmitted back to the ED. Radiology and ED physicians are surveyed to ascertain preferences for CR or traditional screen-film, based on system implementation, image viewing and clinical impact issues. Preliminary results indicate a preference for filmless CR among the ED physicians if digital reliability and speed issues are met. This preference appears to be independent of physician level of experience. Inexperienced radiologists-in-training appear to have less comfort with softcopy reading for primary diagnosis. However, additional training in softcopy reading techniques can improve confidences. Image quality issues are most important tot he radiologist, while speed and reliability are the major issues for ED physicians. Reasons for CR preference include immediate access to images on display stations, near-zero exam retake rates, and improved response time and communication between radiology and the emergency department clinician.

One side effect of installing a clinical PACS Is that users become dependent upon the technology and in some cases it can be very difficult to revert back to a film based system if components fail. The nature of system failures range from slow deterioration of function as seen in the loss of monitor luminance through sudden catastrophic loss of the entire PACS networks. This paper describes the quality control procedures in place at the University of Florida and the automatic notification system that alerts PACS personnel when a failure has happened or is anticipated. The goal is to recover from a failure with a minimum of downtime and no data loss. Routine quality control is practiced on all aspects of PACS, from acquisition, through network routing, through display, and including archiving. Whenever possible, the system components perform self and between platform checks for active processes, file system status, errors in log files, and system uptime. When an error is detected or a exception occurs, an automatic page is sent to a pager with a diagnostic code. Documentation on each code, trouble shooting procedures, and repairs are kept on an intranet server accessible only to people involved in maintaining the PACS. In addition to the automatic paging system for error conditions, acquisition is assured by an automatic fax report sent on a daily basis to all technologists acquiring PACS images to be used as a cross check that all studies are archived prior to being removed from the acquisition systems. Daily quality control is preformed to assure that studies can be moved from each acquisition and contrast adjustment. The results of selected quality control reports will be presented. The intranet documentation server will be described with the automatic pager system. Monitor quality control reports will be described and the cost of quality control will be quantified. As PACS is accepted as a clinical tool, the same standards of quality control must be established as are expected on other equipment used in the diagnostic process.

The functionality and performance expectations of all PACS components must be specified at the time of purchase and tested completely upon delivery to assure customer satisfaction and successful adoption of the new technology. This process may be more elaborate if the customer agrees to serve as a Beta test site for a new component or a new revision of an existing component.A carefully designed test plan will save time at installation, will allow the customer and vendor to agree on expectations, and will assure that the installation will proceed as planned. This paper describes the test procedure used at the University of Florida to accept each PACS component, either a commercial product, or one developed in house. A set of documents contain descriptions of the pre-installation environment, sets of studies to be used in the test, installation checklist, functional usage reports, subjective evaluations, and problem reporting forms. Training and user documentation is also reviewed and 'help lists' are created to help users perform the most common functions. Although details in the documents are changed to match the type of component being tested, the general form of the test remains the same. A formal procedure for testing the functionality and performance of new equipment can save time for both the vendor and the customer and, if specified at the time of purchase, can serve to document the expectations of the customer. Following these procedures will assure a successful installation and improve customer satisfaction.

Incremental costs are determined for a department-wide implementation of picture archiving and communication systems and computed radiography (PACS/CR). This analysis involves determination of all capital and operational costs associated with PACS implementation over an eight-year time horizon. Economic effects are identified, adjusted for time value, and used to calculate Net Present Values (NPV) for each section of the Department of Radiology and for the department as a whole. NPV indicates the full economic impact of a project. Results indicate that a full PACS/CR implementation would not be cost-saving for a large, subspecialized department.However, the cost-savings produced when CR is removed from the analysis indicates that PACS implementation will produce a positive economic impact for departments which have CR already implemented or are committed to CR implementation. Departments that predominantly produce digital images should experience a greater economic savings from using PACS. Furthermore, lossy long-term archive compression rates of 10:1 or greater also produce cost-savings versus conventional imaging equipment.

Investigate the availability and use of radiographic reports both with and without a PACS workstation and investigate physician's opinions on using a workstation. The availability and use of radiographic reports and related patient care were evaluate in a randomized prospective study. Data from a 20 week period of collection, when images were displayed on multiviewers was compared to a 16 week period of data collection, when images were available on an image workstation in the clinical area. Patient care was evaluated by comparing clinical actions. A survey was distributed to the clinical staff to clinical area. Patient care was evaluated by comparing clinical actions. A survey was distributed to the clinical staff to determine their opinion of the image workstation. During periods without the workstation the clinical staff obtained reports o n 90 percent of the exams. During the PACS periods reports were obtained on 51 percent of exams. Sixty four percent of the surveyed clinicians reported a low to moderate level of confidence in interpreting images on the workstation. The percentage of image based clinical actions taken without radiology input increased from 12 percent during periods without the workstation to 74 percent during PACS. A PACS workstation in the clinical area decreases consultation if not supported with timely radiographic reports and may not benefit patient care.

Given today's competitive economic environment, maximization ofproductivity is essential to decrease operational costs and maximize patient throughput. A large scale PACS offers the potential to achieve lower operating costs, increased efficiency, and improved quality of care. A Picture Archival and Communications System (PACS) permits direct display of digital images. Such a system may reduce the need for time consuming processing associated with conventional film based systems

This paper describes the Orthoscope, an equipment for acquisition, processing, and archiving of images of patients mouth or skin. The equipment can capture and process images of single tooth, group of teeth or the whole dental arc. A dentist can easily observe the situation in mouth, demonstrate intended plan of treatment to patient and document its results. A dermatologist can evaluate treatment progress. Unlike other methods, our device shows geometrically undistorted calibrated image.The presented equipment is intended for daily practice. The image processing module is connected to an insurance office system and medical archives. This eliminates time consuming literal description of the patient dental/dermatological status. The images can be used later checking of the diagnosis and treatment.

A system to archive large image sets, such as cardiac cine runs, with near realtime response must address several functional and performance issues, including efficient use of a high performance network connection with standard protocols, an architecture which effectively integrates both short- and long-term mass storage devices, and a flexible data management policy which allows optimization of image distribution and retrieval strategies based on modality and site-specific operational use. Clinical experience with such as archive has allowed evaluation of these systems issues and refinement of a traffic model for cardiac angiography.

The DICOM standard contains information object definitions (IODs) for images generated by each modality type. In order to test if a specific image conforms to its specification it is necessary to formalize the IODs, their mandatory and optional aspects, including the associated natural language conditions. The approach described in this paper is to define a IOD language capable of representing the attribute collections and conditional expressions found in DICOM IODs. The syntax of the IOD language retains as far as possible the familiar tabular form of the DICOM documents allowing easy translation. The set of condition primitives contained in the IOD language is based on an analysis of the types of conditions found in DICOM IODs. The testing of a specific image follows a two level process. First, the description of each IOD defined using the IOD language is compiled into an efficient representation. Second, an image instance is compared against the compiled IOD representation by an image parser and a detailed description of any errors is generated. Formal IOD descriptions have been constructed for CT, MR and SC DICOM IODs and used to evaluate several sets of test images generated by a range of manufacturers during the period 1993 to 1996. All images of the same type, produced using the same software version, normally contain the same kind of errors. We found that overall 92 percent of CT studies, 91 percent of MR studies and 64 percent of SC studies contained at least one violation of their corresponding IOD. Most errors are caused by only a small number of common situations.

The purpose of this paper is to describe the transition of a 1,100 beds tertiary hospital from 50 percent softcopy operation to full PACS operation. For the past 2 years, radiologists and clinicians have been using PACS to provide softcopy services to the outpatient clinics and inpatient wards of orthopedics surgery, neurosurgery and neurology as well as emergency room, surgical intensive care unit, medical intensive unit, pediatrics intensive care unit and neonatal intensive care unit. The examinations requested by these departments account for about 50 percent of hospital's radiological exams. In September 1996, we began the second phase of PACS implementation and installed additional workstations in the remaining wards and clinics, interfaced to PACS additional imaging modalities, and increased the capacity of both the image server and optical juke boxes. As of January 1997, we are in the final phase of moving away from conventional film system to full PACS operation.

The original ACR/NEMA standard, and the more recent DICOM 3.0 standard, address the issue of exchanging images over point-to-point interfaces or across a network. They did not envisage the exchange of images on media. Subsequently the DICOM standard was expanded to define an extensible mechanism for recording images and associated information on interchange media. Interoperability is achieved by defining application specific profiles that specify which medium, which recording format, and what kind of images may be recorded.

We have developed a new teleradiology system that provides a fast response and secure data transmission while using N- ISDN communication and an ISC magneto-optical disk that is specialized for medical use. The system consists of PC-based terminals connected to a N-ISDN line and the ISC disk. The system uses two types of data: the control data needed for various operational functions and the image data. For quick response, only the much smaller quantity of control data is sent through the N-ISDN during the actual conference. The bulk of the image data is sent to each site on duplicate ISC disks before the conference. The displaying and processing of images are executed using the local data on the ISC disk. We used this system for a trial teleconsultation between two hospitals. The response time needed to display a 2-Mbyte image was 4 seconds. The telepointer could be controlled with no noticeable delay by sending only the pointer's coordinates. Also, since the patient images were exchanged via the ISC disks only, unauthorized access to the patient images through the N-ISDN was prevented. Thus, this trial provides a preliminary demonstration of the usefulness of this system for clinical use.

Optimizing limited short term storage (STS) resources requires gradual, systematic changes, monitored and modified within an operational PACS environment. Optimization of the centralized storage requires a balance of exam numbers and types in STS to minimize lengthy retrievals from long term archive. Changes to STS parameters and work procedures were made while monitoring the effects on resource allocation by analyzing disk space temporally. Proportions of disk space allocated to each patient category on STS were measured to approach the desired proportions in a controlled manner. Key factors for STS management were: (1) sophisticated exam prefetching algorithms: HIS/RIS-triggered, body part-related and historically-selected, and (2) a 'storage onion' design allocating various exam categories to layers with differential deletion protection. Hospitals planning for STS space should consider the needs of radiology, wards, outpatient clinics and clinicoradiological conferences for new and historical exams; desired on-line time; and potential increase in image throughput and changing resources, such as an increase in short term storage disk space.

Communication data systems play a central role in medical imaging. Both PACS internal image networks and teleradiology systems need a very large bandwidth to operate. Until recently, industrial standardized protocols have proved to be inadequate to meet the requirements of image transfer at a speed compatible with patient-care needs. PACS vendors, especially when using a shared memory architecture, have developed and inserted proprietary protocols in their systems, causing the well known drawbacks of not standardized environments. Recent technological advances provide potential solutions to these constraints. ATM, above all, provides the aggregate bandwidth and throughput that may be satisfactory to the medical imaging community. At the moment there are no references of working PACS using ATM but several experiments have been reported. This work reports the experience acquired using ATM as a backbone for a distributed medical imaging system under development at CRS4. The attention is focused, in particular, on the performance of DICOM over ATM. It is well know that the transmission subset of DICOM typically uses TCP/IP protocols. A protocol stack is created for running over ATM, where each layer segments and reassembles data according to its rules. This configuration has the great advantage of allowing ATM communication without any change in the DICOM protocol. Moreover it allows the optimization of different networks segments, using different low level protocols, within a single DICOM environment. As a drawback, an overload of protocol data is introduced, lowering the throughput to values far below the nominal ones.

Large hospitals require many viewing stations for image access by referring doctors and personnel from the operating rooms and emergency room. We propose to discuss our experience in providing such review stations with inexpensive PC-based workstations, fast switched Ethernet and a client-server architecture within a large hospital. The bulk of computing processes overhead such as data acquisition, formatting, archiving, database management, routing was performed by large servers and 2 Ethernet giga- switches which are part of our PACS. PC-based workstations performed data retrieval and display functions with user configurable software. Ultrasound, MRI, CT, Angiography and digitized x-ray images were available on the servers. Referring doctors in ICU, CCU were very receptive to this technology. Film use decreased somewhat for hose services using this new technology. PC-based workstations can provide an economically viable solution for image data access by referring physicians and other staff.

This paper describes an innovative framework for a scalable, secure, transparent and distributed medical image-database system which functions in a heterogeneous computer environment using CORBA and DCOM. The framework is designed for implementing telemedicine applications with maximal resource reusability and load balancing. This will enable an existing computer system to be adapted easily to the new system with minimal effort and cost. We have developed a heterogeneous distributed image-database system called MIRage, composed of three subsystems and ORB, based on the CORBA specification as underlying middleware. The ORB, which is a distributed demon structure, enables a cluster of heterogeneous computers to be seen as a single MIRage system, regardless of location and operating system.

At the University of Arizona, software development for image viewing tasks use object-oriented techniques for scalability, portability, cost and the ability to adapt rapidly to changing technology. Object orientation facilitates object-based decomposition, rapid development, code reuse and portability. These techniques were used developing software for a diagnostic system for the Pulmonary Section of Toshiba General Hospital, Tokyo, Japan. Object-oriented analysis and design were based on the Grady Booch method. Implemented used visual C++. Software components are implemented as cooperating objects. The resulting Toshiba-Arizona Viewing Station (TAVS) software system was installed in Tokyo in July 1996 for clinical evaluation. The host system provides 1760 X 2140, grey scale resolution. HIS/RIS integration allows HIS/RIS workstations to control the TAVS. TAVS code has been demonstrated on systems ranging from 'palm-top' computers to high-performance desktop systems. TAVS software objects were then modified and a TAVS system was installed in the University Medical Center, Tucson, Arizona supporting diagnostic image viewing tasks in the Emergency Department. This approach has demonstrated support for rapid development and adaptability to diverse end-user requirements and produced software which can operate across platforms.

Diagnosing nasopharyngeal carcinoma in its early stage plays an important role in the treatment of this disease. We have developed a teleconsultation system to assist rural clinician diagnose the carcinoma under the help of radiologist at metropolitan hospital. In November 1996, we put the system into clinical environment for trial. The purpose is, from the radiologist and physician's points of view, to compare our teleconsultation system to the traditional travel-based consultation. Two hospitals were involved in the trial. We deployed a teleconsultation expert center (TEC) and remote clinician's workstation connected to TEC through publish telephone networks. Three radiologists and one clinician were involved in the three-week trial collecting 35 cases. For each case in our trial, two kinds of consultation were performed: the teleconsultation and then the travel-based one. We, for both ways of consultation, (1) collected all pairs of reports, (2) calculated financial expenditure, and (3) recorded time involved. We also asked the professionals involved for their impression of the system. Data collected from the evaluation has indicated a sanguine feature for diagnosing nasopharyngeal carcinoma using teleconsultation system: the diagnosis accuracy is excellent, the cost and the consultation delay were significantly reduced.

It is shown in the paper that nasopharyngeal carcinoma is commonly encountered in southeastern China and we, considering the urgent need to diagnose the tumor as early as possible and the lack of enough expert radiologists throughout the province, have launched a project to develop a teleconsultation systems with the expert radiologist center at the Zhejiang Cancer Hospital serving rural hospitals in Zhejiang Province. Our client/server teleconsultation system consists of three subsystems: a mini PACS-based Teleconsultation Expert Center, the remote referring physician's workstation and networking subsystem connecting not only LAN but also remote workstation. The software facilities include Preparation Manager, Archiving Manager, Consultation Manager, Report Wizard and Query Manager, all of which simulates a step of the traditional travel-based consultation. In this paper, we also discuss briefly the systems performance and future improvement consideration.

Although PACS has been studied in industrial countries for more than sixteen years, few effort has been made so far to apply PACS technology to such developing areas as most rural regions in CHina. Engineering and clinical problems raised from installing PACS in undeveloped areas has brought many challenges to our system design. In this study, we try to analyze the clinical need of the Chinese hospitals and find out a solution to meet most hospitals' requirements from engineering and clinical points of view, such as system cost, ease of deployment, user interface, maintenance difficulty, etc., thus provide patients with better medical serve at affordable cost. First of all, we analyzed data collected from Zhejiang Cancer Hospital (ZCH) and take hospitals' financial situation into consideration. then according to the analysis, we made our choices for hardware and software platform, digitizer and storage device. The development of mini PACS is interacted by clinicians and radiologists from ZCH. They showed great interest in the downsizing PACS that does not risk much of the system performance. It is promising that our solution will be accepted in developing areas.

Lockheed Martin (Loral) has installed PACS with associated teleradiology in several tens of hospitals. The PACS that have been installed have been the basis for a shift to filmless radiology in many of the hospitals. the basic structure for the PACS and the teleradiology that is being used is outlined. The way that the PACS are being used in the hospitals is instructive. The three most used areas for radiology in the hospital are the wards including the ICU wards, the emergency room, and the orthopedics clinic. The examinations are mostly CR images with 20 percent to 30 percent of the examinations being CT, MR, and ultrasound exams. The PACS are being used to realize improved productivity for radiology and for the clinicians. For radiology the same staff is being used for 30 to 50 percent more workload. For the clinicians 10 to 20 percent of their time is being saved in dealing with radiology images. The improved productivity stems from the high performance of the PACS that has been designed and installed. Images are available on any workstation in the hospital within less than two seconds, even during the busiest hour of the day. The examination management functions to restrict the attention of any one user to the examinations that are of interest. The examination management organizes the workflow through the radiology department and the hospital, improving the service of the radiology department by reducing the time until the information from a radiology examination is available. The remaining weak link in the PACS system is transcription. The examination can be acquired, read, an the report dictated in much less than ten minutes. The transcription of the dictated reports can take from a few hours to a few days. The addition of automatic transcription services will remove this weak link.

A network of hospitals is planned that will be able to share radiology services. The hospitals and clinics involved will be related in four different ways: (1) Outlying clinics using a hospital radiology service; (2) Multiple cooperating radiology services with one administration; (3) Multiple cooperating radiology services with separate administrations; (4) Shared archive services on the network. The expected operation in each of the scenarios is discussed including an estimate of the amount of shared traffic between the providers. The services provided by a single administration will result in the largest sharing of radiology exams and the greatest utilization of the communication network. Separate administrations are expected to share patients and exams much less frequently. The network archive can be used to reduce the cost of an installation with somewhat reduced archive performance. The sharing of services is facilitated by an effective interaction between the separate imaging systems. A shared administration means that one database can be used to organize data flow and workflow around the hospitals. The interaction of two databases when there are two separate administrations changes the level of cooperation that is possible. A distributed PACS will be installed in several hospitals: clinics associated with the DeWitt Hospital at Ft. Belvoir, Virginia; The DeWitt Army Hospital at Ft. Belvoir, Virginia; Walter Reed Army Medical Center, Bethesda, Maryland; National Naval Medical Center, Bethesda, Maryland. DeWitt, its clinics and Walter Reed Army Medical Center are under one administration. The National Naval Medical Center is under a separate administration. The ability to cooperate in providing radiology services across these institutions will be established and the level of sharing across the institutions will be measured. The archive node will provide archive services for those hospitals without an archive, will provide archive services for those radiological exams that are older than are retained on local archives, and will provide a backup archive in case of catastrophic failure at a hospital.

The rapid and dramatic shifts within the US healthcare industry have created unprecedented needs to implement changes in the delivery systems. These changes must not only address the access to healthcare, but the costs of delivery, and outcomes reporting. The resulting vision to address these needs has been called the Integrated Healthcare Solution whose core is the Electronic Patient Record. The integration of information by itself is not the issue, nor will it address the challenges in front of the healthcare providers. The process and business of healthcare delivery must adopt, apply and expand its use of technology which can assist in re-engineering the tools for healthcare. Imaging is becoming a larger part of the practice of healthcare both as a recorder of health status and as a defensive record for gatekeepers of healthcare. It is thus imperative that imaging specialists adopt technology which competitively integrates them into the process, reduces the risk, and positively effects the outcome.

This paper investigates the design and implementation of a multimedia telemedicine application being undertaken by the Imaging Science and Information Systems Center of the Department of Radiology and the Division of Nephrology of the Department of Medicine at the Georgetown University Medical Center (GUMC). The Renal Dialysis Patient Monitoring network links GUMC, a remote outpatient dialysis clinic, and a nephrologist's home. The primary functions of the network are to provide telemedicine services to renal dialysis patients, to create, manage, transfer and use electronic health data, and to provide decision support and information services for physicians, nurses and health care workers. The technical parameters for designing and implementing such a network are discussed.

At the National Library of Medicine we are developing a digital atlas to serve as a reference tool for the interpretation of cervical and lumbar spine x-rays. The atlas contains representative images for four grades of severity for cervical/lumbar spondylolisthesis. A prototype version of the atlas has been built using images for which expert rheumatologist readers reached exact agreement in grading. The atlas functionality includes the ability to display cervical and lumbar anatomy, display of single images or multiple simultaneous images, image processing functions, and capability to ad user-defined images to the atlas. Images are selected for display by the user specifying feature and grade. Currently, the atlas runs on a Sun SPARC workstation under the Solaris operating system. THe initial use of the atlas is to aid in reading a collection of 17,000 NHANES II digitized x-rays. The atlas may also be used as a general digital reference tool for the standardized interpretation of digital x-rays for osteoarthritis. We are investigating further development of the atlas to accommodate a wider set of images, to operate on multiple platforms, and to be accessible via the WWW.

Managed care continues to drive healthcare providers in search of systems that improve productivity and reduce costs. The integration and centralization of information and image management systems are the central design theme of many evolving enterprise solutions. One of the major value drivers of these integrated image and information systems is the time and location independence of the clinical decision. Images and information being presented consistently and independent of the device or workstation is crucial to the enterprise's productivity improvements. This is true for information used for primary clinical decisions as well as for secondary or follow-up treatment. A system must deliver clinical information consistently, location to location as well as over time. The reliability of the system and consistency of the information are crucial design criteria. The integration and distribution of medical imagery increase the complexity of attaining and maintaining information consistency. The design of these enterprise systems implies the need for display devices to be monitored, controlled and maintained. The methods that have evolved break into three classifications. (I) Assume a standard response. (II) Measure the local display response and locally correct the display device. (III) Measure the local display response and transmit this information encapsulated in a device profile. The specific architecture will dictate the appropriate method for establishing display consistency. In all cases, establishing display consistency requires that one measure or model the response of the display device. The ability of an image management system to deliver the productivity goals of an enterprise depends on this basic functionality.

The technology is not the bottleneck anymore in PACS implementation, it has become clear that the key to the success of PACS is understanding the current process, the end-user requirements, and how these processes will change with the introduction of PACS. We will discuss how implementation of PACS changed the working procedures in the Radiology department of Visby Hospital. Visby Hospital in Gotland, Sweden has approximately 160 beds. The Radiology department performs approximately 33,000 examinations per year and is capable of offering a broad range of diagnostic imaging services including CT and MRI. When a new facility was built in 1994, the decision was made to go for filmless operation and a modern information infrastructure. The new facility went operational by the end of 1994, in August 1995 almost filmless operation was reached. Continuing effort and attention is being paid to further simplify the workflow and working procedures in the Radiology department, and to improve the services offered to referring physicians. Although the project aimed at filmless operation, the main goal was to organize for efficient operation and excellent service, thereby maintaining high quality standards and employee satisfaction.

Significant clinical value can result from the transparent integration ofpatient information, including medical images, test results, clinical reports and administrative data, to provide a unified patient record in a format that is well-suited to use by clinical specialists and subspecialists. The development of such a capability, however, has often been hampered by the existence of legacy systems that store such data in proprietary formats and by the development of technology-driven products that do not reflect the needs ofthe clinicians that will use them. The Berlin Medical (BERMED) system addresses these issues through the use of the meta-patient record, an integration layer that provides both directory services and retrieval services for distributed, heterogeneous patient information. The system currently integrates CT, MR. digital angiography and computed radiography modalities along with a hospital information system and a text-based information system used for the reporting of clinical observations, diagnoses and test results. A multi-media video conferencing and collaboration capability is also provided to support consultation, teaching and other types of interaction among clinicians at different BERMED sites. The BERMED system has been developed incrementally since 1992 and is currently in routine clinical use by a wide community of users. Keywords: Electronic medical records, computerized patient records, medical informatics.

Our objective is to offer clinicians wider access to evolving medical image processing (MIP) techniques, crucial to improve assessment and quantification of physiological processes, but difficult to handle for non-specialists in MIP. Based on artificial intelligence techniques, our approach consists in the development of a knowledge-based program supervision system, automating the management of MIP libraries. It comprises a library of programs, a knowledge base capturing the expertise about programs and data and a supervision engine. It selects, organizes and executes the appropriate MIP programs given a goal to achieve and a data set, with dynamic feedback based on the results obtained. It also advises users in the development of new procedures chaining MIP programs.. We have experimented the approach for an application of factor analysis of medical image sequences as a means of predicting the response of osteosarcoma to chemotherapy, with both MRI and NM dynamic image sequences. As a result our program supervision system frees clinical end-users from performing tasks outside their competence, permitting them to concentrate on clinical issues. Therefore our approach enables a better exploitation of possibilities offered by MIP and higher quality results, both in terms of robustness and reliability.

DICOM semantics refers to the specification of meaning of DICOM messages exchanged between two DICOM-compliant systems. DICOM-compliant PACS networks may fail to achieve interoperability due to different variations in allowable DICOM semantics used by different implementors. We have specified the beginnings of a DICOM reference architecture by designing a generic PACS network, selecting certain PACS functions commonly implemented in DICOM application entities and making explicit assignments of various DICOM service classes to carry out the selected application level functionality. A generic PACS based on the reference architecture presented here is being implemented with the intention off providing Internet access to it for interoperability testing.

This paper attempts to forecast tow to five years to understand the future PACS environment and is the result of reviews of literature and interviews with nearly thirty organization sand individuals representing the PACS community. Two to five years was set as a realistic limit to projections although thoughts for the future of digital medical imaging beyond five years are included. The variance in projections even in the short term is significant and any projection beyond five years will be even more uncertain. The organizations that contributed to the interviews include academic centers, the federal government, consultants and vendors of PACS technology. The vendor products span the industry to include capture of images at the modality level, image management and distribution systems, services, and speech recognition. This paper will place the changes that will occur in PACS within the context of the larger changes that are occurring in health care, the practice of image acquisition and interpretation, and information systems. Selected technologies that will influence PACS are reviewed in more depth with a view towards the affect that they will have on PACS and the interpretation of images.

Business process automation utilizing information technology is a requirement today for business survival. This will also become true within the radiology department. Operational changes within the radiology department, supported or enabled by PACS, will be essential to every radiology department. Operational changes outside the radiology department are also supported or enabled by PACS, but in a different manner. Outside the radiology department, images are an element of information content utilized in the decision process. As such, PACS is an element of the computerized patient record (CPR). This paper will explore how business processes can be optimized utilizing information technology automation in constructing a CPR. AN object-oriented methodology is proposed to consistently and precisely describe both the business process and the required automation to be provided by the CPR. By customizing the CPR user interfaces, the information technology department is able to support the creation of truly optimized automated business processes. The underlying technical foundation that enables creating fully customized user interfaces into the CPR is the system architecture. It also provides access to CPR functionality and information independent of a predefined, static, user interface.

In 1993 in Time Magazine Lance Morrow wrote a seminal article entitled The Tempting of America. "America has entered the age of the contingent, ",he says - "ofthe just-in-time work force - fluid,flexible, disposable. . This is the future." In actual fact, this is not the future, this has been and is an ever-present reality -we have not only failed to take advantage of it , we have even refused to recognize it for the tool that it is or the advantages it confers. From time immemorial, for conquerors and their armies who achieved success after unqualified success, it was this ethic of flexibility that formed the underpinnings of their every winning strategy. The commander who could mass huge armies or resort to small commando groups was the one who trounced the opposition. fluidity and adaptability translated directly into his ability to succeed -allowinghim to deal with varying contingencies successfully. .Themore agile and versatile his army, the more varied his armamentarium the more likely he was to win a skirmish, a battle or a war.