Picture archiving and communication in radiology: An American perspective

Computers provide an excellent tool for handling the task of organizing a radiology teaching file. Currently available computerized teaching files are either film-based, slide-based, or use laser-disc video technology for image display. There are obvious advantages to having the management of radiologic images under the control of a computer, and the need for a higher resolution alternative to video laser-disc technology becomes apparent when one tries to computerize a chest radiology teaching file. We describe the prototype of such a system, named MIRTLE, (the Mallinckrodt Institute of Radiology Teaching and Learning Environment) which was designed to integrate text under the control of a custom data base with high-resolution digital images from a Picture Archiving and Communications System. This system with its easy-to-use windows environment should allow a significant increase in the use of the radiology teaching file.     

Picture archiving and communication system bandwidth and storage requirements

The purpose of this work was to determine the requirements for image storage and network bandwidth for a total digital department in a moderate sized academic radiology department. Data from the radiology information system was combined with image production information to produce a model of image acquisition. Destinations of images to reading rooms were studied to determine the final distributions of film. All findings were used to model the flow of data that would be expected if the images in the department were completely digital. Using today's standards, the department would produce approximately 15.7 Gbytes of data per day or 3.5 Tbytes of data per year if all acquisitions were digital. The peak acquisition rate would be 1.8. Gbytes per hour with a sustained rate greater than 1 Gbyte per hour for most of the working day. The anticipated bandwidth for the total digital department exceeded the capabilities of the existing picture archiving and communication system equipment. A distributed networked archive solution was shown to optimized access to images by radiologists and referring clinicians.     

Clinical impact of picture archiving and communication systems: Evaluation of a prototype system

Opinion surveys were gathered before and 6 months after installation of a prototype picture archiving and communication system (PACS) (PACS/1, Siemens Medical Systems, Iselin, NJ). Median turnaround times and the percent of delayed or missing reports were calculated for 1,026 baseline and 8,438 follow-up studies at 6 months. Neuroradiological (neuro) computed tomography (CT) used PACS, while neuro magnetic resonance (MR), body CT, and body MR served as controls. The opinion surveys showed improved service in all categories, including those not directly affected by PACS. PACS images favorably impressed 86% of respondents, but most considered the system too slow, unreliable, and the storage capacity too low. A majority of 81% recommended against purchase of PACS now. There was an overall increase in the median report turnaround time for both neuro CT and the controls. Neuro CT showed a 41% decrease in delayed or missing reports, but controls also showed similar decreases. The effects of this prototype PACS on turnaround time or on report delivery could not be distinguished from section-wide changes in CT and MR services. Future improvements in PACS should vigorously address increased speed, reliability, and storage capacity.     

Introduction to SCAR 97: The 14th symposium for computer applications in radiology: Picture archiving and communication systems in practice

The effectiveness of a hospital information system (HIS) and a radiological information system (RIS) was evaluated to optimize preparation for the planned full clinical operation of a picture archiving and communication system (PACS), which is now linked experimentally to the HIS and the RIS. One thousand IC (integrated circuit) cards were used for time studies and flow studies in the hospital. Measurements were performed on image examination order entry, image examination, reporting, and image delivery times. Even though after the HIS and the RIS operation only a small amount of time savings were realized in each time fraction component, such as in the patient movement time, examination time, and film delivery time, the total turn-around time was shortened markedly, by more than 23 hours on average. It was verified that the HIS and the RIS was beneficial in the outpatient clinics of the orthopedic department. Our method of measurement employing IC cards before and after HIS and RIS operations can be applied in other hospitals.     

Picture archiving and communication system activities at the Mayo Clinic Rochester

This report summarizes Mayo Clinic Rochester’s experience with a picture archiving and communication system (PACS) to date and discusses the principles that have guided implementation.     

Content-based retrieval in picture archiving and communication systems

A COntent-Based Retrieval Architecture (COBRA) for picture archiving and communication systems (PACS) is introduced. COBRA improves the diagnosis, research, and training capabilities of PACS systems by adding retrieval by content features to those systems. COBRA is an open architecture based on widely used health care and technology standards. In addition to regular PACS components, COBRA includes additional components to handle representation, storage, and content-based similarity retrieval. Within COBRA, an anatomy classification algorithm is introduced to automatically classify PACS studies based on their anatomy. Such a classification allows the use of different segmentation and image-processing algorithms for different anatomies. COBRA uses primitive retrieval criteria such as color, texture, shape, and more complex criteria including object-based spatial relations and regions of interest. A prototype content-based retrieval system for MR brain images was developed to illustrate the concepts introduced in COBRA.     

Picture archiving and communication system design issues: The importance of modelling and simulation

Picture archiving communication system (PACS) development turns out to be very complex. Due to both the vast amount of data and the complexity of hospital organizations, currently only small-scale systems have been realized. And although the experiences obtained with these systems are essential, there is a risk for underestimating the complexity and requirements inherent in hospital-wide PACS systems. In this paper, it is advocated that modelling and simulation be used as tools to obtain insight into the behavior and structure of future PACS systems. Modelling and simulation can also be used to actively support the design of PACS, especially its software. In order to capture the full complexity of PACS in a simulation model, and to take full advantage of simulation as a design tool, the development of a new modelling method has begun. This method is based on semantic data models and decision processes, and can be used for both system analysis and design. The first systems modelled with this method were imaging procedures in a hospital and a computer network. The resulting simulation models are a direct reflection of reality, and have a high degree of modularity. Consequently, in spite of the complexity of the systems, their models are easy to understand and maintain.     

Evolution of picture archiving and communication systems—1989

Several areas of partial picture archiving and communication systems (PACS) applications such as teleradiology, nuclear medicine, archiving modules, and systems for handling computed tomography and magnetic resonance digital data are mentioned prior to the discussion of a fully functional PACS system. Some of the present and future social implications of PACS are reviewed. Experience to date with a pilot system called MicroRSTAR at the Massachusetts General Hospital is described.

     

Picture archiving and communication system training for physicians: Lessons learned at the Baltimore VA Medical Center

Physicians practicing at the “filmless” Baltimore VA Medical Center need to be proficient in the use of the picture archiving and communication system (PACS) to be able to view radiologic images and accompanying reports. PACS training is necessary to assure optimal patient care and to satisfy potential medicolegal requirements. Providing such training is the responsibility of both the Imaging Department and the hospital. Training in the use of the PACS at the Baltimore VA is conducted by an on-site application specialist. Data were collected from interviews with the trainer, training log sheets, and physician surveys. Although 100% of radiologists received formal training, only 22% of nonradiologists were formally trained; 32% of these physicians identified themselves as having been trained by their peers and 41% stated they were self-trained. We identified two goals of a PACS training program. The first is to teach physicians how to retrieve images and reports from current as well as prior studies and display them on a computer workstation. Secondly, the training should include instruction on the use of the various workstation tools to enhance image interpretation. Imaging requirements and usage by different physician groups vary, and PACS training should be tailored accordingly. Difficulties in the scheduling of training sessions during working hours and the widespread use of a “generic” log-on identification have contributed to the low (22%) compliance of nonradiologists with the formal training program. Although we believe that one-on-one training is most effective and can be best tailored to the needs and computer expertise of an individual particular physician, computer based training (both on and off-line) may provide an acceptable, and in some cases, a preferred alternative.     

A methodology for the economic assessment of picture archiving and communication systems

Most economic studies of picture archiving and communication systems (PACS) to date, including our own, have focused on the perspectives of the radiology department and its direct costs. However, many researchers have suggested additional cost savings that may accrue to the medical center as a whole through increased operational capacity, fewer lost images, rapid simultaneous access to images, and other decreases in resource utilization. We describe here an economic analysis framework we have developed to estimate these potential additional savings. Our framework is comprised of two parallel measurement methods. The first method estimates the cost of care actually delivered through online capture of charge entries from the hospital’s billing computer and from the clinical practices’ billing database. Multiple regression analyses will be used to model cost of care, length of stay, and other estimates of resource utilization. The second method is the observational measurement of actual resource utilization, such as technologist time, frequency and duration of film searches, and equipment utilization rates. The costs associated with changes in resource use will be estimated using wage rates and other standard economic methods. Our working hypothesis is that after controlling for the underlying clinical and demographic differences among patients, patients imaged using a PACS will have shorter lengths of stay, shorter exam performance times, and decreased costs of care. We expect the results of our analysis to explain and resolve some of the conflicting views of the cost-effectiveness of PACS.     

A modular method for evaluating the performance of picture archiving and communication systems

Modeling can be used to predict the performance of picture archiving and communication system (PACS) configurations under various load conditions at an early design stage. This is important because choices made early in the design of a system can have a significant imapct on the performance of the resulting implementation. Because PACS consist of many types of components, it is important to do such evaluations in a modular manner, so that alternative configurations and designs can be easily investigated. Stochastic activity networks (SANs) and reduced base model construction methods can aid in doing this. SANs are a model type particularly suited to the evaluation of systems in which several activities may be in progress concurrently, and each activity may affect the others through the results of its completion. Together with SANs, reduced base model construction methods provide a means to build highly modular models, in which models of particular components can be easily reused. In this article, we investigate the use of SANs and reduced base model construction techniques in evaluating PACS. Construction and solution of the models is done using UltraSAN, a graphic-oriented software tool for model specification, analysis, and simulation. The method is illustrated via the evaluation of a realistically sized PACS for a typical United States hospital of 300 to 400 beds, and the derivation of system response times and component utilizations.     

Trauma center imaging problems: Proposed solution with picture archiving communication systems

Radiologic support for trauma center activities presents special problems that are discussed. This article proposed the use of a picture archiving communication system (PACS) as a potential solution. A sample PACS for this purpose is described to illustrate this approach.     

Experience and design recommendations for picture archiving and communication systems in the surgical setting

An analysis of the efficacy of a picture archiving and communication system (PACS) in the surgical domain was undertaken at the Baltimore Veterans Affairs Medical Center. Interviews with surgeons and staff were conducted and supplemented by direct radiologist observation in the operating room (OR) and surgical outpatient clinic to determine patterns of routine clinical PACS use, levels of satisfaction both within and outside of the OR, and perceptions of the relative efficacy of the system in comparison to film. These data as well as suggestions from the surgical staff members were used to make recommendations for specific modifications in PACS design and operation to improve the current system and to help prescribe design improvements for future PAC systems. A high level of satisfaction with the system was found and the use of PACS was favored over film by a majority of surgeons and their staff. Findings of this study suggest that the design of a hospital-wide PAC system must have the flexibility to accommodate the specific requirements of a wide variety of end-users in their unique hospital environments.     

A literature review on communication between picture archiving and communication systems and radiology information systems and/or hospital information systems

The purpose of this literature review is to present the concepts surrounding the issue of communication between imaging systems and information systems in radiology and the literature about them. Picture archiving and communication systems (PACS) were developed to combine viewing of modality images, archiving, and distribution of images. When PACS is integrated/interfaced with radiology information systems (RIS) or hospital information systems (HIS), it can merge patient demographics, medical records, and images. To address several issues surrounding communication between PACS and HIS/RIS and to make interface development easier and faster, various organizations have developed standards for the formatting and transfer of clinical data. Additional work continues to better handle these issues. Communication protocol Health Level 7 (HL7) is a standard application protocol used for electronic text data exchange in health care by most HIS/RIS. The imaging communication protocol for PACS is the Digital Imaging and Communications in Medicine (DICOM) standard specification protocol that describes the means of formatting and exchanging images and associated information.     

The reality of picture archiving and communication systems (PACS): A survey

Toward the end of 1997 vendors were succeeding in installing picture, archiving and communication systems (PACS) in larger numbers. It was hard to separate fact from fiction at times. This survey was undertaken by 2 members of the academic community to confirm what was operational, how well the installed systems worked, and what they were doing. Fax questionnaires were sent to nearly 1,000 facilities worldwide to identify PACS of any size in clinical operation on a date certain, February 1, 1998. A total of 177 PACS were identified. Facilities furnished responses during the first survey period from May 1 to November 1, 1998. A second survey, done in February and March of 2000, sought long-term follow-up data. Many systems operated 5 or more types of modalities. Computed tomography (CT) was the most common modality type at 83%, but the distribution of the rest held surprises. There also was an unexpectedly large use of soft copy reading and filmless operation in 1998. Clear trends toward increased use of computed radiography and digital radiography and a significant expansion on the percentage of all of a facility's examinations on the PACS were seen over the 2 years. Satisfaction with original PACS vendors was relatively high. Eighty-nine percent remained with their original vendor. Only 10 sites reported they changed vendors, and 4 facilities said they abandoned their system. The users reported their expectations of the PACS had been met in 81% of cases. Some (65%) declared their systems were cost effective. The most striking response was that 97% of the users would recommend PACS to others.     

Data clustering and other archive retrieval strategies for teleradiology and picture archiving and communication systems

A key advantage in the conversion from film-based to digital radiology is the possibility of a long-term on line electronic archival of patient studies. The popular approach based on optical disk jukeboxes for the long-term archive and magnetic disk storage for data caching is not economically attractive because of the cost of both the jukebox and the medium. Strategies for extending the archival system design with a tape jukebox have been studied. The proposed strategy calls for the use of high-ratio lossy compression together with low-cost tape storage to make long-term on line archiving more affordable. An intelligent prefetching algorithm based on hospital information system and radiologic information system triggers, which in turn are augmented by manual case preparation, can effectively overcome the longer latency of ad hoc retrievals. This longer latency is caused by both system-level bottlenecks and the sequential access constraint of the tape drive. Strategies for image clustering and tape allocation by patient classification also enhance retrieval efficiency. This archival design using image compression, prefetching, and clustering could be implemented in many of the existing teleradiology and picture archiving and communication systems.