The effect of image processing on chest radiograph interpretations in a PACS environment

The question of whether image processing affects a radiologist's diagnostic performance is becoming more important as the digital modalities proliferate. In the multi-observer study reported, the performance of radiologists who interpret a series of posteroanterior digitized chest images displayed on a high-resolution workstation, with and without a set of image processing options, is determined. These include brightness, contrast, reverse look-up tables (black-bone), and two edge enhancement options. Three hundred images were evaluated twice (once in each mode) by each of seven board-certified radiologists, who recorded their confidence ratings for the presence or absence of one or more of the following abnormalities: interstitial disease, nodule, and pneumothorax. The original, unprocessed digital image was available for reference for those sessions in which the processing options were available. With the exception of one reader, receiver operating characteristic (ROC) analysis showed no statistically significant difference between the two modes (with and without processing) for the detection of any of the different abnormalities by individual readers. Likewise, the group as a whole showed no significant difference (P less than .05) for detection of any of the three abnormalities between the two reading modes.     

Enterprise PACS and image distribution.

Around the world now, because of the need to improve operation efficiency and better cost effective healthcare, many large-scale healthcare enterprises have been formed. Each of these enterprises groups hospitals, medical centers, and clinics together as one enterprise healthcare network. The management of these enterprises recognizes the importance of using PACS and image distribution as a key technology in cost-effective healthcare delivery in the enterprise level. As a result, many large-scale enterprise level PACS/image distribution pilot studies, full design and implementation, are underway. The purpose of this paper is to provide readers an overall view of the current status of enterprise PACS and image distribution. reviews three large-scale enterprise PACS/image distribution systems in USA, Germany, and South Korean. The concept of enterprise level PACS/image distribution, its characteristics and ingredients are then discussed. Business models for enterprise level implementation available by the private medical imaging and system integration industry are highlighted. One current system under development in designing a healthcare enterprise level chest tuberculosis (TB) screening in Hong Kong is described in detail.     

Trends in PACS image storage and archive.

PACS is widely used in hospitals and is considered a mission critical system for around-the-clock daily clinical operation. Scheduled or unscheduled downtime of the main PACS archive storage or server could potentially cripple the entire PACS operation. This is especially the case in a filmless hospital environment. Therefore, in a downtime event, it is most desirable for users to have only a minimal performance impact without interruption of clinical data flow or loss of data and to have available historical PACS studies. This paper summarizes some of the developments in the design and implementation of a reliable PACS that insures maximum uptime for end users while preserving the integrity of the PACS data and making it available during downtime events. It also details strategy for developing proper clinical workflow contingency procedures when a scheduled downtime event to the main archive storage and server occurs. Specifically, the design and implementation of a fault-tolerant (FT) main archive server, the development of a FT back-up archive using an application service provider (ASP) model, and the clinical experiences while upgrading a main archive server and migrating the stored PACS data to new storage media will be discussed.     

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

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

PACS and Web-based image distribution and display.

Picture archiving and communication system (PACS) delivers images to the display workstations mostly through digital image communication in medicine (DICOM) protocols in radiology departments, and there are lots of medical applications in healthcare community needing to access PACS images for different application purposes. In this paper, we first reviewed a hospital-integrated PACS image data flow and typical diagnostic display software architecture, and discussed some Web technologies and Web-based image application server architectures, as well as image accessing and viewing methods in these architectures. Then, we present one approach to develop component-based image display architecture and use image processing and display component to build a diagnostic display workstation, and also, give a method to integrate this component into Web-based image distribution server to enable users using Web browsers to access, view and manipulate PACS DICOM images as easy as with PACS display workstations. Finally, we test and evaluate the performance of image loading and displaying by using the diagnostic display workstation and the component-based Web display system, the experimental results show that the image distribution and display performance from the Web server to browser clients is similar with that of the image loading and displaying procedure of the diagnostic workstation as more browser clients accessing the Web server at same time. We also discuss the advantages and disadvantages of the Web-based image distribution and display in different medical applications.     

Primary CT diagnosis of abdominal masses in a PACS environment

Whether the display medium--film versus cathode ray tube (CRT)--affects observer performance during interpretation of computed tomographic (CT) images is an important research issue in these times of implementation and growth of picture archiving and communications systems in radiology. The authors performed a multiobserver receiver operating characteristic (ROC) study to determine the performance of radiologists who read abdominal CT studies displayed on film, as well as on a high-resolution workstation (video monitor) that made use of three different display modes. A total of 166 examinations were evaluated by eight radiologists, who recorded their ordinal confidence ratings of the demonstration of presence or absence of abdominal masses. ROC analysis showed small differences in the confidence ratings assigned by individual readers for the detection and interpretation tasks. Results for the group as a whole showed no significant reduction or improvement in observer performance when ratings for any one of the workstation display modes were analyzed. The results of this study demonstrate that current CRT display technology is adequate for enabling the primary detection of abdominal masses with CT examinations.     

Medical evacuation in a low intensity conflict environment.

Medical evacuation is one of the major missions of the Medical Element, Joint Task Force-Bravo (ME-JTF-B) in Honduras, which operates in a low intensity conflict environment. ME-JTF-B conducted 10 missions during the primary author's deployment. Critical examination of these missions led to several performance improvements. The most important is that of deploying on all missions an emergency medical evaluation team with TACSAT (a field portable transmitter-receiver which can communicate via satellite over long distances). The second most important is that of close command and control of every mission by the hospital commander and the chief administrator. Other performance improvements are listed below.     

The effect of clinical history on chest radiograph interpretations in a PACS environment

The effect that accompanying patient information has on diagnostic accuracy in radiologic interpretation has been studied by many researchers but remains a matter of contention. Experiments in the past emphasized the chest film because this procedure is the one done most frequently in radiology. However, with the increasing importance of digital imaging, the role of patient history in these procedures should be assessed. The use of a model computerized patient history in the interpretation of digitized chest images that were displayed on a high-resolution workstation was studied. Two hundred forty-seven selected posteroanterior chest images that indicated disease and that indicated no disease were interpreted in random sequence by five board-certified radiologists, with and without accompanying patient histories. Readers were prompted by the response forms to evaluate images for the possible occurrence of interstitial diseases, nodules, or pneumothorax. No significant differences (P = .05) in the detection of these abnormalities were noted between case readings with and without history for any of the radiologists or for the group as a whole. However, this methodology reflects a direct interpretation approach. The results of this study may not necessarily be applicable to individual prompts, different imaging procedures, or other abnormalities.     

医学影像存储与传输系统中影像数据流的管理及其实现方式

目的：探讨医学影像存储与传输系统（PACS）影像数据流程的管理模式和实现过程。方法：作者医院PACS经过2期建设完成了全数字化改造，所有影像设备均已接入PACS系统。系统采用中央存储管理模式，并通过对系统工作流和影像数据流的控制和管理，提高了影像诊断执行过程的系统响应速率。作者将着重基于全数字化改造后PACS影像流程运行环境和管理模式，分析影像数据流程类型、过程及实现方式。结果：作者医院PACS系统影像数据流程管理主要涉及2类：影像归档存储过程的影像转存（forward）过程。前者采用集中管理模式，对不同的影像类型根据诊断过程的需求采用各异的归档存储时间表，如CT、MR等影像类型执行集中一次性存档，而对需要立即完成诊断过程的常规X线影像则执行即刻归档存储操作；后者通过PACS中央管理服务器上运行的工作流管理软件实现，即对完成归档存储的影像，通过自动路由的过程将其进一步送往具体实施诊断过程的部门和位置。结论：影像数据流管理是影响PACS系统功能执行效率的关键因素，应根据用户特定的运行环境、任务和需求进行设计和实现。     

PACS及其在影像科图像管理中的应用

目的初步探讨图像存档及通信系统(PACS)应用于影像科图像管理的价值。方法比较影像科PACS与传统法两种完全不同的图像管理模式。结果通过比较显露出传统胶片管理模式的诸多缺点,PACS是目前最好的图像管理模式。结论随着现代化医院影像科的发展,PACS图像管理模式必将取代传统的胶片管理模式,医学影像的“无胶片”时代已悄然来临。     

PACS中医学影像质量控制系统的研究与设计

目的解决PACS系统使用而带来的质量保证问题。方法研究设计用于影像设备和图像采集网关之间的医学影像质量控制系统。结果医学影像质量控制系统可以部分解决PACS的质量保证问题。结论医学影像质量控制系统可以在最大程度上做到对错误影像或低质量影像早发现、早修改,从而进一步提高PACS中医学信息和医学影像的准确性。     

PACS development in Asia.

First, history of PACS in Japan from 1982 to 2002 has been investigated. By 2002 total of 1468 PACS units have been installed. Of these, 1174 are small-size PACS with less than four image display terminals, 203 are medium-size with 5-14 terminals, and 91 are large-size with 15 up to 1300 terminals. The main nine large-size PACS of 91 have been retrospectively investigated from 1984 for PACS experiments and from 1989 for PACS operation. Most of these nine hospitals have increased the number of PACS terminals by installing additional PACS units, instead of reinforcing the existing single PACS. The use of DICOM interfaces has increased the number of modalities connected to PACS and influenced the spreading of PACS installations in Japan. The status of HIS and RIS coupling to PACS, and the use of PACS in primary diagnosis or in image referral are discussed. Assessment of PACS is now in an early stage. Baseline studies of HIS/RIS/PACS effectiveness have been carried out to assess quantitatively the PACS merit. Second, history of PACS development in Korea is described. Very acute climbing up of filmless PACS diffusion was observed from 2000 to 2002. The reasons seem to be lack of domestic X-ray film industry, economic crisis in 1997 and PACS Reimbursement Act in health insurance in Korea. Third, the Hong Kong Wide Area Image Distribution/PACS Project is reported. It is now under phase 1 of design and partial implementation employing the latest and the highest ends of advanced technology such as failure resilience.     

PACS developments in Europe.

Although the concept of picture archiving and communications systems (PACS) was developed in Europe during the latter part of the 1970s, no working system was completed at that time. The first PACS implementations took place in the United States in the early 1980s, e.g. at Pennsylvania University, UCLA, and Kansas City University. Some more or less successful PACS developments also took place in Europe in the 1980s, particularly in the Netherlands, Belgium, Austria, the United Kingdom, France, Italy, Scandinavia, and Germany. Most systems could be characterized by their focus on a single department, such as radiology or nuclear medicine. European hospital-wide PACS with high visibility evolved in the early 1990s in London (Hammersmith Hospital) and Vienna (SMZO). These were followed during the latter part of the 1990s by approximately 10-20 PACS installations in each of the major industrialized countries of Europe. Wide-area PACS covering several health care institutions in a region are now in the process of being implemented in a number of European countries. Because of limitations of space, some countries, for i.e. Switzerland, Denmark, Finland, Spain, Greece, as well as Eastern European countries, etc. could not be appropriately represented in this paper.