The digital imaging workstation

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

Three years'' experience with an all-digital nuclear medicine department

We describe our all-digital, filmless, department of nuclear medicine, which has been fully operational for 3 years. The approach to the design and implementation of a nuclear medicine picture archiving and communication system (PACS) is discussed, as well as enhancements found to be necessary or desirable during our 3 years of experience using the system. Studies are initially viewed on remote monitors in the reading room, and transferred from multiple vendor's computers to the PACS by floppy disc network. Scans are analyzed on networked image workstations using a variety of software imaging tools. Reports are dictated into a digital voice storage system, allowing the referring physician immediate telephone access. The dictated report is typed into a computer, electronically edited, reviewed, billed, and printed for appropriate distribution on an integrated medical information system. The final report is stored on the PACS, along with the scan image and other patient information on 1-gigabyte removable optical discs. Two networked optical disc drives allow us to have approximately 3 years of our department's studies available instantly, allowing recall of previous studies for comparison with the current scan. Emergency night and weekend studies are sent via modern over normal phone lines to the on-call physician, who has a similar image workstation at home. Digital image storage allows for easy manipulation of the data, such as gray scale manipulation and cine (movie) display. Cost analysis shows significant savings compared with a film-based department. We conclude that an all-digital nuclear medicine department is practical, cost effective, and beneficial to both patients and staff.     

PACS workstation design

This paper covers some of the recent concepts in designing a digital imaging workstation in a multimodality Picture Archiving and Communications Systems (PACS) network. A workstation in a multimodality PACS network must access, display, and analyze digital images from different imaging modalities with very different formats. The user interface should allow clinicians with minimal or no computer manipulation skills to use complex analysis tools. General guidelines of a graphics oriented user interface, based on windows and icons, are proposed. Instantaneous (real-time) response in the primary display and processing functions is vital for user acceptance. The hardware architectural concepts to achieve such a performance speed are described. Finally, a workstation environment conducive to comfortable viewing by the radiologists is discussed.     

The electronic viewbox

OBJECTIVE: We describe an effective, resource-free method for facilitating the comparison of film-based and PACS-based radiographic studies. CONCLUSION: Side-by-side comparison of film-based and PACS-based radiographic studies is often inconvenient because of the absence of an ergonomically satisfactory viewbox near the workstation. With a simple maneuver, any PACS display monitor can be used as a rudimentary viewbox, providing a convenient and ergonomically effective alternative.     

Integrating digital systems: commitment and collaboration

One year ago, the radiology department at Ball Memorial Hospital, a 350-bed facility in Muncie, IN, was completely film-based. The need to support a new all-digital, 35-room emergency department (ED) hastened the facility's transition to a digital environment. Today, with the exception of mammography, the hospital's imaging services are now digital. To develop and implement the project, the hospital formed an internal implementation team. An independent consultant was also hired to evaluate the impact of these new technologies and to provide an estimated cost payback. After research, site visits, and vendor demonstrations, the hospital selected a single vendor for its picture archiving and communication system (PACS), digital radiography (DR), computed radiography (CR), and overall project management. The DR system was installed in the ED to provide digital image capture for a full range of trauma exams. The ED also initially began utilizing a Web-based PACS distribution originally implemented for after-hours teleradiology. The majority of the hospital's imaging studies are captured with 2 multi-cassette CR systems that serve 7 exam rooms in the radiology department. The hospital also installed remote operations panels to expedite entry of patient and exam information. Technologists readily embraced both CR and DR systems. The Web distribution system now transmits images to hospital-based computers and to 150 remote referring physicians. The PACS platform automatically e-mails key images and radiology reports to referring physicians. Authorized physicians can also request reports and images on an as-needed basis. The PACS vendor had previously performed multiple integrations with the radiology information system (RIS) vendor; the integration of PACS and RIS was extremely smooth. One of the critical components of a successful conversion is experienced, dedicated management. The hospital retained professional project management services to facilitate implementation and to ensure adequate training for all users.     

PACS adoption

Once the decision has been made to adopt PACS instead of a film-based radiology practice, there are a number of hurdles to jump. Users need to be aware of the impact the change will make on end users and be prepared to address issues that arise before they become problems. Someone who understands the technology of PACS must be identified to help make an informed decision about vendor selection, network architecture, workstation functionality, and archives. A PACS administrator should have the tools available to avoid problems with the system after implementation and should be able to repair the inevitable mistakes that will happen. Hopefully, this article can serve as a starting point for a potential new PACS adoption.     

医学影像存档与通讯系统的开发与初步应用

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

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

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

An automated PACS workstation interface: a timesaving enhancement

OBJECTIVE: Interface design is a key element in the efficient use of a picture archiving and communication system (PACS) workstation. In many cases, multiple mouse clicks or keyboard commands are required to open and close a case, to mark it as complete, and to retrieve and allocate screen positions to the next case. We evaluated the work flow effect of software designed for automated image display in which all of these operations are consolidated in a single mouse click. CONCLUSION: Automated image display increases efficiency in image interpretation and remedies the normally cluttered presentation environment. At our institution, acceptance of automated image display has been overwhelmingly positive. In fact, automated image display has improved radiologist productivity.     

超声PACS系统构建问题的探讨

目的:探讨有关超声PACS系统构建问题.材料和方法:对PACS系统在华山医院超声医学科的应用进行评估.结果:成功建立超声PACS系统,并在临床应用中取得良好效果.结论:构建PACS系统需要解决多方面的问题.PACS在超声医学领域有着良好的前景.     

The impact of a picture archiving and communication system (PACS) upon an intensive care unit

OBJECTIVE: The aim of the study was to assess the effect of the introduction of PACS (Picture Archiving and Communication System) upon image availability in an Intensive Care Unit (ICU) and the consequent impact upon the behaviour of the ICU physicians, in terms of the initiation of image-based clinical actions. DESIGN: A before and after study was used to compare the speed of image availability prior to, and following, the implementation of a hospital-wide PACS. SETTING: The research was part of an economic evaluation of PACS at Hammersmith Hospital, West London. PATIENTS AND PARTICIPANTS: All ICU patients who were X-rayed during two pre-PACS and one post-PACS data collection periods were included within the study. MEASUREMENTS: The times of: the X-ray request; acquisition; availability on ICU; and of any image-based clinical action taken by the ICU physician were recorded by radiographers and ICU physicians. RESULTS: PACS significantly reduced the time between request and image availability on ICU for routine X-rays but did not have any measurable impact upon the time clinical actions were initiated by ICU physicians. The data on non-routine images were statistically inconclusive. CONCLUSIONS: This study shows that PACS significantly improves the speed of delivery of routine images to the ICU, but it appears that the instigation of image-based clinical actions is determined by other organisational factors in ICU, such as ward rounds, rather than the availability of the image for viewing. Further work is required on non-routine X-rays to clarify the impact of PACS on physician behaviour in clinically urgent situations.     

Comparison of full-field digital mammography workstation and conventional picture archiving and communication system in image quality and diagnostic performance

The object of this study was to compare of full-field digital mammography (FFDM) workstation and conventional picture archiving and communication systems (PACS) in image quality and diagnostic performance. We assembled 80 masses and 80 microcalcifications. Images were displayed on workstation, 5M, and 3M PACS monitors. The image quality for mammograms on workstation was significantly better than that for mammograms on PACS monitors. The sensitivity and NPV for microcalcifications on workstation were higher than those on PACS monitors. The conventional PACS cannot substitute for a FFDM workstation for mammographic evaluation.     

Picture archiving and communication systems: an overview.

Organizational techniques that enable small departments to function efficiently often fail as departments become larger. With the recent growth in imaging technology, the capacity of film-based systems to meet the increasing needs of radiology departments has decreased. Electronic picture archiving and communication systems (PACS) have been developed in an attempt to provide economical storage, rapid retrieval of images, access to images acquired with multiple modalities, and simultaneous access at multiple sites. Input to a PACS may come from digital or analog sources (when the latter have been digitized). A PACS consists primarily of an image acquisition device (an electronic gateway to the system), data management system (a specialized computer system that controls the flow of information on the network), image storage devices (both short- and long-term archives), transmission network (which serves local or wide areas), display stations (which include a computer, text monitor, image monitors, and a user interface), and devices to produce hard-copy images (currently, a multiformat or laser camera). The goals of PACS are to improve operational efficiency while maintaining or improving diagnostic ability.     

Evaluation of a PACS workstation for assessment of body CT studies

Conventional hardcopy images from 266 body CT studies were compared with those provided at a commercially available picture archiving communication system (PACS) workstation. Unprocessed PACS images were larger but otherwise precisely duplicated hardcopy images. The PACS images were evaluated before and after application of various image processing/display features. Approximately three-quarters of the cases were depicted equally well with PACS and hardcopy, but in one quarter of the cases, diagnostic features were judged to be shown more clearly at the PACS workstation. When PACS images were viewed first, change in diagnosis after subsequent hardcopy inspection was infrequent (confidence change: 4%; different findings: 2%). Conversely, when hardcopy images were viewed first, change in diagnosis after subsequent PACS inspection was more frequent (confidence change: 19%; different findings: 8%). Specialized image manipulation available on PACS was critical for its performance. Review of cases with new findings discovered during the second inspection showed the majority of them to be clinically significant, true-positives discovered by PACS. We conclude that PACS is a useful modality for interpretation of body CT images.     

Infrastructure design of a picture archiving and communication system.

A picture archiving and communication system (PACS) infrastructure is the necessary framework to integrate distributed and heterogeneous imaging systems, provide intelligent data-base management of all radiology-related information, arrange an efficient means of viewing, analyzing, and documenting study results, and furnish a mechanism for effectively communicating study results to the referring physician. The PACS infrastructure consists of a basic skeleton of hardware components integrated by standardized, flexible software subsystems. This review describes these concepts and basic building blocks drawn from our original investigation, past experience, and the current clinical system in our radiology department.     

A PACS-based interactive teaching module for radiologic sciences.

This article describes an interactive teaching module, linked to a picture archiving and communications system (PACS) data base, for teaching radiology. The module is currently tailored to MR images but can be adapted to any other imaging technique. An algorithm has been developed that allows the use of MR images acquired with routine clinical protocols and stored in the data base to yield, in real time, images at any other arbitrary TE and TR. In the browse mode, the user can study either the effect of different scan parameters or clinical cases on synthesized or acquired images. The quiz mode has multiple-choice questions and answers, accompanied by images. In the teaching mode, the instructor has access to the clinical data base and WRITE privileges for setting up the browse or quiz mode. The module achieves considerable flexibility when linked to the PACS, with access to all archived images and the ability to subsequently synthesize MR images at arbitrary TE and TR values in real time. The module is also "dynamic" in character, in that the instructor can easily add new cases and comments to the teaching files, both to enhance its clinical aspects and to reflect advances in technology.     

Personal computer versus workstation display: observer performance in detection of wrist fractures on digital radiographs

PURPOSE: To retrospectively compare the accuracy of observer performance with personal computer (PC) compared with that with dedicated picture archiving and communication system (PACS) workstation display in the detection of wrist fractures on computed radiographs. MATERIALS AND METHODS: This study was conducted according to the principles of the Declaration of Helsinki (2002 version) of the World Medical Association. The institutional clinical board approved the study; informed consent was not required. Seven observers independently assessed randomized anonymous digital radiographs of the wrist from 259 subjects; 146 had fractures, and 113 were healthy control subjects (151 male and 108 female subjects; average age, 33 years). Follow-up radiographs and/or computed tomographic scans were used as the reference standard for patients with fractures, and follow-up radiographs and/or clinical history data were used as the reference standard for controls. The PC was a standard hospital machine with a 17-inch (43-cm) color monitor with which Web browser display software was used. The PACS workstation had two portrait 21-inch (53-cm) monochrome monitors that displayed 2300 lines. The observers assigned scores to the radiographs on a scale of 1 (no fracture) to 5 (definite fracture). Receiver operating characteristic (ROC) curves, sensitivity, specificity, and accuracy were compared. RESULTS: The areas under the ROC curves were almost identical for the PC and workstation (0.910 vs 0.918, respectively; difference, 0.008; 95% confidence interval: -0.029, 0.013). The average sensitivity with the PC was almost identical to that with the workstation (85% vs 84%, respectively), as was the average specificity (82% vs 81%, respectively). The average accuracy (83%) was the same for both. CONCLUSION: The results of this study showed that there was no difference in accuracy of observer performance for detection of wrist fractures with a PC compared with that with a PACS workstation.     

From Being a Radiologist to Watching a Radiologist: Impact of Filmless Operation on the Training of Radiology Residents

RATIONALE AND OBJECTIVES: The authors performed this study to investigate the impact of changing from a film-based image interpretation system to one using digital image workstations on the training of radiology residents in the interpretation of radiographs. MATERIALS AND METHODS: Data were collected during a period when a conventional system of image interpretation with hard-copy images and multiviewers was used and during a period when digital image workstations were used. During each period, it was noted whether the first interpretation of the radiographs was performed by a radiology resident, by an attending radiologist, or as a group effort including both an attending radiologist and a radiology resident(s). In addition, it was noted whether a radiology resident or an attending radiologist dictated the report. RESULTS: The proportion of images first interpreted by the radiology resident alone decreased from 38% (53 of 139) when using the conventional system to 17% (34 of 199) after the switch to interpreting images on the workstations (P = .001). During the film-based period, radiology residents dictated 45% of reports (141 of 312), but during the workstation period, radiology residents dictated only 4% of reports (24 of 667; P = .001). CONCLUSION: The authors observed a decrease in autonomous participation by radiology residents in image interpretation and dictation of reports and an increase in "group reading" after the switch from a film-based system to a workstation system.     

Accuracy of interpretation of CT scans: comparing PACS monitor displays and hard-copy images

OBJECTIVE: The purpose of this study was to determine the relative diagnostic accuracy of radiologists in the interpretation of CT scans using a computer workstation in comparison with using film. MATERIALS AND METHODS: Four board-certified radiologists with extensive soft-copy experience interpreted 117 CT scans in four anatomic regions using films displayed on an alternator and images displayed on a four-monitor workstation. The radiologists were asked to interpret the scans in their usual fashion and were aware that both the time required to review the study and the accuracy of the reports were being assessed. The radiologists' diagnostic impressions were compared with those of a consensus panel and scored for accuracy. RESULTS: Soft-copy interpretation using computer workstations was found to produce statistically significant improvement in combined measurements of sensitivity, specificity, and overall accuracy for chest, brain, and chest-abdominal CT scans compared with film interpretation. CONCLUSION: PACS (picture archiving and communication system) offers radiologists the potential for improved accuracy in CT interpretation compared with traditional film-based interpretation.     

Enhanced visualization processing: effect on workflow.

RATIONALE AND OBJECTIVES: Soft-copy viewing of digital radiographs allows for image processing to improve visualization of anatomy and lesions, but it can take more time than film-based viewing. Enhanced visualization processing (EVP) was developed to increase the latitude of an image without reducing the vital contrast, potentially reducing the need for the radiologist to manipulate images. This study examined the influence of processing radiographic images with EVP on workflow in a picture archiving and communications system (PACS). MATERIALS AND METHODS: Portable computed radiographic chest images were obtained and processed either with EVP or without. A security camera with a videocassette recorder was positioned above the PACS workstation. Four radiologists reviewed the images during their normal work schedule. The current diagnostic image was used to determine if the case contained EVP or non-EVP images. The videotapes of the sessions were reviewed to determine diagnostic viewing times and how zoom and/or window and level manipulation was used. RESULTS: Viewing time was significantly longer for the non-EVP than the EVP cases. The difference occurred with all readers. Window and level manipulation was used on 35% of the EVP and 41% of the non-EVP images. Zoom was used on 64% of the EVP and 69% of the non-EVP images. Average time spent using zoom and window and level manipulation was significantly shorter with the EVP than with the non-EVP images. CONCLUSION: EVP of chest images displayed on PACS monitors significantly improved workflow as measured by viewing time. EVP decreased use of window and level manipulation and zooming and the amount of time each one was used.