William J. Chimiak

The digital radiology environment

The problems of implementing a digital radiology environment are addressed, focusing on the role of communications. Because the digital radiology environment is essentially a medical image multimedia system, the medical information industry could take advantage of recent advances in managing multimedia systems that deal with applications, such as prepress formatting and CAE/CAD/CAM. The paper describes the experience of the Bowman Gray School of Medicine of Wake Forest University relative to the digital radiology environment. Next, impediments to the implementation of a digital radiology environment are presented. Suggestions to the ACR/NEMA Digital Imaging and Communications (DICOM) Standard, a standard being jointly developed by the American College of Radiology (ACR) and the National Electronics Manufacturing Association (NEMA), are examined, and suggestions for its use in the digital radiology environment are given. A digital radiology environment architecture is proposed. >

An architecture for Naval telemedicine

Navy fleets have a defined overall objective for mission readiness impacted by the health of personnel aboard the ships. Medical treatment facilities on the ships determines the degree of mission readiness. The paper describes the concepts and technologies necessary to establish a Naval telemedicine system, which can drastically improve health care delivery. It consists of various combinations of the following components: Fleet Naval Medical Consultation and Diagnostic Centers, Shipboard Naval Medical Consultation and Diagnostic Centers (hospital ship or combatant ships with medical specialists on board), and Remote Medical Referring Centers such as a ship, a small Naval station annex, or a field hospital. This Naval telemedicine architecture delivers clinical medicine and continuing medical education (CME) by means of computers, video-conferencing systems, or telephony to enhance the quality of care through improved access to research, medical and nonmedical imaging, remote consultations, patient clinical data, and multimedia medical education programs. It integrates the informatics infrastructure and provides a medical telepresence among participants.

Architecture for a high-performance tele-ultrasound system

Clinical prototypes of digital tele-ultrasound systems at the Bowman Gray School of Medicine have provided insight into various design architectures. Until network equipment costs decrease, hybrid systems often provide good cost/feature mixes by using high-cost networking equipment only when digital networking is required. Within the hospital using remote ultrasound system, a video and audio router interconnects the video output of ultrasound modalities and technologist communications subsystems. This is done either manually or by remote signaling, depending on the size of the ultrasound infrastructure and the cost of a remote signaling subsystem. For extramural sites and in hospital areas too distant for cost- effective analog switching techniques, an appropriate coder/decoder (CODEC), with echo cancellation, is used to transfer the audio and visual information to a CODEC in the viewing station location. The CODECs can be T1 (1.544 Mbps) CODECs for areas that cannot be reached economically at asynchronous transfer mode (ATM) data rates. This is contingent upon the diagnostic quality of the output of the T1 CODECs. Otherwise, high-speed CODECs are used with 45 Mbps DS-3 or ATM transmission facilities. This system allows full use of existing hospital infrastructures while adapting to emerging data communications infrastructures being implemented.

The rural and global medical informatics consortium and network for radiology services

Telemedicine systems that provide health delivery services to rural clinics and hospitals are being demonstrated in clinical settings. This paper summarizes the research and consortia projects at the University of Arizona Medical Center. The paper describes the Rural and Global Picture Archiving and Communications (PACS) environment developed under a National Science Foundation grant. The Rural and Global PACS environment includes many workstations, database, and networking components and is treated as a large distributed system. These components are described in this paper. The multimedia services for radiology provided by the Rural and Global PACS are described and their performance is measured. Finally, the current research work using the Open Software Foundations distributed computing environment (OSF DCE) services is described. An OSF DCE testbed for the Rural and Global PACS is described and the rationale of using OSF DCE in the project is presented.

Synchronized voice and image annotation in remote consultation and diagnosis for the global PACS

A Global PACS is a medical imaging system which enables the doctors to capture, archive, and retrieve medical images over wide area networks. In previous work, we have developed a distributed software for remote consultation and diagnosis in a Global PACS environment over the Internet or NSFNET. The doctors are able to interactively perform a remote consultation with basic image annotation commands. In this paper, we present a new mechanism for adding voice to this scenario and performing synchronization of voice and image annotation in a remote consultation and diagnosis session.

An adaptive multi-disciplinary telemedicine system

Telemedicine is often assumed to apply to all medical services delivered over a telecommunications channel. However, in this paper, a dynamically adaptive multi-disciplinary workstation (DAMDW) is discussed which is usable by a significant number of specialists and primary care physicians which not only adapts to the specialty of the physician, but also to the bandwidth available to the participating health care centers. The telemedicine system architecture described easily incorporates advances in computer and communication technology that minimizes early obsolescence. In addition, the system maximizes remote logistical support, providing significant operational cost reduction. The DAMDW is a based on the Unix operating system with software components which can be used on various computer architectures that provide cost alternatives during the system acquisition process. The DAMDW incorporates informatics interfaces as well as commercial videoconferencing software and videoconferencing software obtained using anonymous FTP on the Internet.

Fault tolerant high-performance PACS network design and implementation

The Wake Forest University School of Medicine and the Wake Forest University/Baptist Medical Center (WFUBMC) are implementing a second generation PACS. The first generation PACS provided helpful information about the functional and temporal requirements of the system. It highlighted the importance of image retrieval speed, system availability, RIS/HIS integration, the ability to rapidly view images on any PACS workstation, network bandwidth, equipment redundancy, and the ability for the system to evolve using standards-based components. This paper deals with the network design and implementation of the PACS. The physical layout of the hospital areas served by the PACS, the choice of network equipment and installation issues encountered are addressed. Efforts to optimize fault tolerance are discussed. The PACS network is a gigabit, mixed-media network based on LAN emulation over ATM (LANE) with a rapid migration from LANE to Multiple Protocols Over ATM (MPOA) planned. Two fault-tolerant backbone ATM switches serve to distribute network accesses with two load-balancing 622 megabit per second (Mbps) OC-12 interconnections. The switch was sized to be upgradable to provide a 2.54 Gbps OC-48 interconnection with an OC-12 interconnection as a load-balancing backup. Modalities connect with legacy network interface cards to a switched-ethernet device. This device has two 155 Mbps OC-3 load-balancing uplinks to each of the backbone ATM switches of the PACS. This provides a fault-tolerant logical connection to the modality servers which pass verified DICOM images to the PACS servers and proper PACS diagnostic workstations. Where fiber pulls were prohibitively expensive, edge ATM switches were installed with an OC-12 uplink to a backbone ATM switches. The PACS and data base servers are fault-tolerant, hot-swappable Sun Enterprise Servers with an OC-12 connection to a backbone ATM switch and a fast-ethernet connection to a back-up network. The workstations come with 10/100 BASET autosense cards. A redundant switched-ethernet network will be installed to provide yet another degree of network fault-tolerance. The switched-ethernet devices are connected to each of the backbone ATM switches with two-load-balancing OC-3 connections to provide fault-tolerant connectivity in the event of a primary network failure.

Modeling and simulation of the USAVRE network and radiology operations

The U.S. Army Medical Command, lead by the Brooke Army Medical Center, has embarked on a visionary project. The U.S. Army Virtual Radiology Environment (USAVRE) is a CONUS-based network that connects all the Armys major medical centers and Regional Medical Commands (RMC). The purpose of the USAVRE is to improve the quality, access, and cost of radiology services in the Army via the use of state-of-the-art medical imaging, computer, and networking technologies. The USAVRE contains multimedia viewing workstations; database archive systems are based on a distributed computing environment using Common Object Request Broker Architecture (CORBA) middleware protocols. The underlying telecommunications network is an ATM-based backbone network that connects the RMC regional networks and PACS networks at medical centers and RMC clinics. This project is a collaborative effort between Army, university, and industry centers with expertise in teleradiology and Global PACS applications. This paper describes a model and simulation of the USAVRE for performance evaluation purposes. As a first step the results of a Technology Assessment and Requirements Analysis (TARA) -- an analysis of the workload in Army radiology departments, their equipment and their staffing. Using the TARA data and other workload information, we have developed a very detailed analysis of the workload and workflow patterns of our Medical Treatment Facilities. We are embarking on modeling and simulation strategies, which will form the foundation for the VRE network. The workload analysis is performed for each radiology modality in a RMC site. The workload consists of the number of examinations per modality, type of images per exam, number of images per exam, and size of images. The frequency for store and forward cases, second readings, and interactive consultation cases are also determined. These parameters are translated into the model described below. The model for the USAVRE is hierarchical in nature. There are three levels to the model: (1) Network model of the Cable Bundling Initiative (CBI) network and base networks (CUITIN), (2) Protocol model, including network, transport, and middleware protocols, such TCP/IP and Common Object Request Broker Architecture (CORBA) protocols, and (3) USAVRE Application layer model, including database archive systems, acquisition equipment, viewing workstations, and operations and management. The Network layer of the model contains the ATM-based backbone network provided by the CBI, interfaces into the RMC regional networks and the PACS networks at the medical centers and RMC sites. The CBI network currently is a DS-3 (45 Mbps) backbone consisting of three major hubs, at Ft. Leavenworth, KS, Ft. Belvoir, VA, and Ft. McPherson, GA. The medical center PACS networks are 100 Mbps and 1 Gbps networks. The RMC site networks are 100 Mbps speeds. The model is very beneficial in studying the multimedia transfer and operations characteristics of the USAVRE before it is completely built and deployed.

Multimedia features of a dynamically adaptive telemedicine system

A dynamically adaptive multidisciplinary workstation (DAMDW) architecture delivers very good multimedia telemedicine service. The DAMDW is a Unix workstation with software components that operate on various computer architectures. It adapts to the speciality of the physician and to the bandwidth available to the participating health care centers. The network flexibility of the DAMDW makes it usable in an existing telecommunications infrastructure while incorporating advances in computer and communication technology. This feature prevents early obsolescence. The DAMDW utilizes most telecommunications services. This allows multimedia features that improve with increased bandwidth without discarding capital equipment. It also simplifies connectivity to standard local area networks (LANs) in hospitals.

Multimedia architecture for teleradiology in the U.S. Army virtual radiology environment

The U.S. Army Medical Command, lead by the Brooke Army Medical Center, has embarked on a futuristic project which will revolutionize the practice of radiology in the DoD. The U.S. Army Virtual Radiology Environment (USAVRE) is a CONUS-based network that connects all the Armys major medical centers and Regional Medical Commands (RMC). The purpose of the USAVRE is to improve the quality, access, and cost of radiology services in the Army via the use of state-of-the-art medical imaging, computer, and networking technologies. The USAVRE contains multimedia-viewing workstations for static and dynamic modality cases. The storage and archiving systems are based on a distributed computing environment using Common Object Request Broker Architecture (CORBA) middleware protocols. Collaboration between archive centers and viewing workstations are managed by CORBA functions and multimedia object streams. The underlying Telecommunications network is an ATM based backbone network that connects to the RMC regional networks and PACS local networks at medical centers and RMC clinics. The U.S. Army Information Systems Engineering Command (USAISEC) at Ft. Huachuca, AZ is responsible for the ATM backbone network to the RMC sites. The virtual Radiology services in a USAVRE must be applied to several radiology modalities in a virtual network environment. In this discussion, we assume the existence of several PACS networks within a USAVRE environment that have a need to exchange multimedia images and patient information. We define a multimedia collaborative distributed computing environment (DCE) in medical imaging and radiology as a collection of collaborating PACS networks with workstations and image archive systems for the purposes of acquiring and exchanging patient static and video sequence images; storage, retrieval, and archival of those images; performing image analysis and multimedia consultation on patient cases; operation and management of the network to optimize its resources; and to improve the quality and access of the radiology services to the patients. This paper describes the open systems architecture for the USAVRE, including the PACS and Global PACS user equipment. This project is a collaborative effort between military, university, and industry centers with expertise in Teleradiology and Global PACS applications.