Kris Maloney

Evaluation of the ACR-NEMA standard for communications in digital radiology

An implementation and evaluation of a prototype multivendor communications system which complies with the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) standard for communications in digital radiology is discussed. The system allows communications between interfaces from different manufacturers within a networked environment. The implementation includes network software compatible with the International Standards Organizations Open Systems Interconnect standard. The experience of the implementation effort and the evaluation of the system provide the basis for a critique of the ACR-NEMA standard. It is concluded that the ACR-NEMA standard is not well suited for application to the networked environment of picture archiving and communications systems. Two possible solutions are recommended for this problem. The first is a major revision of the existing standard. The second is the development of a family of network communications standards for digital radiology.

Comparison Of Digital Workstations And Conventional Reading For Evaluation Of User Interfaces In Digital Radiology

The User Interface Study Group at the University of Arizona is investigating the interaction of Radiologists with digital workstations. Using the Arizona Viewing Console we have conducted an experiment to compare a digital workstation with a particular conventional reading process used for cases from a local Health Maintenance Organization. A model consisting of three distinct phases of activity was developed to describe conventional reading process. From this model software was developed for the Arizona Viewing Console to approximate the process. Radiologists were then video taped reading similar sets of cases at each workstation and the tapes were analyzed for frequency of hand movements and time required for each phase of the process. This study provides a comparison between conventional reading and a digital workstation. This paper describes the reading process, the model and its approximation on the digital workstation, as well as the analysis of the video tapes.

Comparison Of A Digital Workstation And A Film Alternator

In the Department of Radiology at the University of Arizona investigation of the interaction of Radiologists with digital workstations is conducted by the User Interface Study Group. Using the Arizona Viewing Console we have conducted an experiment to compare one digital workstation with reading done at a film alternator (also known as a rotator). A model consisting of distinct phases of activity was developed to describe alternator reading process. From this model software was developed for the Arizona Viewing Console to approximate the process. Radiologists were then video taped reading similar sets of cases at each workstation and the tapes were analyzed for frequency of hand movements and time required for each phase of the process. The information gathered provides a comparison between alternator reading and reading at a digital workstation. This paper describes the reading process, the model and its approximation on the digital workstation, as well as the analysis of the video tapes.

Network software for picture archiving and communications systems

Realization of the full potential of picture archiving and communications system in radiology requires a well-designed, flexible software architecture. The architecture must be well designed to accommodate the high volume and short response times required of the system. It must be flexible to allow the software to be layered upon a variety of existing technologies and easily migrated onto emerging technology. A software architecture for a prototype network was designed. This software was originally intended to support communications across an ACR-NEMA standard interface. However, it has been designed according to ISO/OSI and most of the layers are completely independent of the physical communications media. This implementation has demonstrated the benefits of adhering to a well-accepted standard. The authors are planning to migrate the software onto Ethernet and are looking toward ISDN.<<ETX>>

A Fiber-Optic Network System for PACS

This paper describes installing the first two portions of a fiber-optic based image-transmission network. The network topology is a star. The system is controlled by logical circuit switching of broadcast signals. High-speed operation is attained by two means: First, the signalling speed of the network is 144 Megabits/second. Second, wavelength multiplexing is used to separate the control signals and image-transmission signals. This paper describes the installation and integration of two arms of the network star. The arms include: the star coupler (SC), two network interface units (NIU), two interface translation units (NIU), and two units of imaging equipment (IE). Development of the system components was done separately at the Department of Radiology, University of Arizona (UofA) in the U.S.A. and at the Toshiba Medical Imaging Laboratories in Japan. The SC and NIUs were constructed by Toshiba while the ITUs and IEs were constructed by the UofA. The system integration was done at the University of Arizona by a team with members from both locations.

Comparison Of Film/Screen To Electronic Review Consoles: Phase II

This paper describes the psychophysical evaluation of a prototype electronic viewing console developed by the Toshiba Corporation. The evaluation consisted of two phases. In the first phase, four radiologists viewed 10 pediatric images. Each image was viewed first with no enhancement, second with window and level, and third with pan and zoom. A diagnosis and certainty was recorded for each of these viewings. The areas under the curve (AUC) were 0.80, 0.86, and 0.91 for no enhancement, window and level, and pan and zoom, respectively, compared to an AUC of 0.90 for film. The second phase was a clinical comparison of the capabilities of this electronic system to those of conventional film and computed radiography using cholangiography studies of the biliary system. Thirty-six images were viewed by five radiologists, and free use of enhancement functions was allowed. The areas under the curve for the images seen on the viewing console, conventional film, and computed radiography film images were 0.84, 0.84, and 0.83, respectively. The authors conclude that for examinations of these anatomic regions, pediatric chest and cholangiograms, each of them depicting a variety of pathologic processes, electronic viewing consoles seem to convey the needed information for accurate diagnosis.

Evaluation of radiologist performance using telemedicine services

Observer performance of radiologists using a telemedicine service was evaluated. Diagnoses between the rural and consulting radiologists agreed 84% of the time. The main reason for disagreement was extent of lesion rather than type or absence/presence. Consulting times and image quality were considered adequate.

Design of the Interface Between the Intensive Care Unit and Hospital/Radiology Information Systems a

This paper discusses the design and the implementation of the interface between the Medical Image Access System for the Intensive Care Unit (MIAS/ICU) and the hospital/radiology information systems (HIS/RIS) operated by Information Systems Services (ISS) of the University Medical Center, Tucson, Arizona. The report addresses the problem of obtaining current status information on patients to be used in the MIAS/ICU system. Hospital information systems operated by ISS exchange patient information using Health Level 7 (HL7) messages over the hospital Ethernet network. The MIAS/ICU consists of 5 components: an image reader to read image plates from portable x-ray units; Image Server to store images; Data Server which is a database for patient information; Viewing Workstation a commercial workstation with two monitors used by physicians at ICU for early, uno cial viewing of images; these components are integrated by an FDDI network. These images need to be supplemented by patients current status information. A gateway was designed and implemented to extract useful data from HL7 messages and pass them to the data server. Most medical information exchange interface designs tend to be proprietary, hard-wired, and application speci c. This design and implementation is open; can be easily customizable to suit di erent medical institutions; allowed us to exibly experiment with di erent con gurations; and is operating reliably in a clinical setting. It is a generic design for interfaces between medical information applications. This paper brie y reviews the HL7 standard. It then provides an overview of the MIAS/ICU project, the gateway software architecture, the gateway software implementation, and design limitations. This gateway is currently operational within the MIAS/ICU system at University Medical Center, Tucson, Arizona. 1 2 1 This work is supported by: a gift from Fuji Medical Systems U.S.A., funding and support from University Medical Center, and an equipment grant from Digital Equipment Corporation. 2 International Phoenix Conference on Computers and Communications (IPCCC), Phoenix, Arizona, April 12-15, 1994

Assessing the impact of a medical image access system

We have developed and installed a Medical Image Access System in an intensive care unit. Images are acquired and transmitted automatically to this system, thus expanding on the previous results of Shile et. al. It is our goal to determine what effect regular, sustained availability of image data in the clinic has on the Intensive Care Unit and the Department of Radiology. Our system is installed and has been in regular use in the hospital since late August of 1993. Since the time of installation we have been collecting usage information from both the manual and automated systems. From this data we are performing the standard measures established by DeSimone et. al. Our initial results support the original findings that image availability in the clinic leads to earlier patient care decision based on the image data. However, our findings do not seem to indicate that there is a breakdown of communication between the clinician and the radiologist as a result of the use of the clinical display system. In addition to the established measure we are investigating other criteria to measure time saved by both the clinician and radiologist. The results are reported in this paper.

Maximizing End-to-End Throughput in Image Communication Systems

We describe two systems designed and constructed in the Radiology Department of the University of Arizona.