In 1998 we surveyed our radiologists on teleradiology satisfaction. Results were generally positive. In 2002 we experienced a sevenfold case increase in teleradiology volume. The present study surveyed the radiologists again. The hypothesis was that, with increased case volume and radiologist experience with the system, ratings would increase. Image quality was excellent/good, although plain film and ultra sound (US) had more fair/poor ratings. Monitors, navigation, image processing, and Web-based reporting were rated as excellent/good. The voice-recognition system was rated poorly. Diagnostic confidence was about the same as for film. Exceptions were magnetic resonance imaging (MRI) US, and plain film. Up to 10% of cases are unreadable because of poor image quality, not enough images, or inadequate patient history. Overall, the radiologists are satisfied, although some improvements can be made.

The Arizona Telemedicine Program was established in July 1996 by the Arizona state legislature. The organizational center for the program is the Arizona Health Sciences Center in Tucson. Key goals for the program include increased access to specialty services for rural, underserved populations; development of cost-effective telemedicine services; and expansion of opportunities for education of health professionals in rural areas. The program provides several levels of services based on both store-and-forward and real-time interactive applications. The telecommunication infrastructures is provided by two methods: The first is a private asynchronous transfer mode network established and operated by program personnel. The second is dial-up access via the public switched telephone network. After an extensive period of organization and vendor evaluations, most of the private network was implemented between June and December 1997. This paper describes experiences establishing the asynchronous transfer mode network.

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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 Organization's 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.

Extension ofthe infrastructure supporting Network-centric operations to the Tactical Edge relies primarily on wireless communications. The nature of these communications ensures that the channel will vary dramatically due to environmental and propagation effects, as well as potential interferers. Tactical operations introduce additional impairment due to mobility. With convergence to Internet Protocol (IP) centric networking, voice communications at the tactical edge will be increasingly dependent on Voice over IP (VoIP). In a packet-based protocol such as IP, two critical factors affecting latency sensitive applications such as VoIP are end-to-end delay and packet loss. Making a tradeoff between these two factors is of prime consideration in designing the jitter buffer playout scheme. Since voice packets are delayed in the network randomly, the jitter buffer is required to maintain consistently spaced playout of voice samples. A deep buffer protects against packet loss due to late arrival ofpackets. However, a deep buffer introduces mouth-to-ear delay that ultimately degrades the perceived voice quality. We describe an algorithm for dynamically estimating network delay using time series models. This enables the VoIP application to manage the jitter buffer to maintain a minimum playout buffer, while keeping the packet loss rate above a minimal threshold to maintain consistent voice quality. Our proposed algorithm limits sensitivity to short-term delay jitter and is very reactive to bursty network traffic. Simulation results show an improvement of II% to 15% using metrics based on the subjective ITU E-model (R-factor) when compared against currently used playout methods. The improvement gain from the proposed method may be of particular significance for the challenges of supporting bursty dynamic changing wireless communication channel.

zona has been operating a teleradiology program for almost 2 years. The goal of this project was to characterize the types of cases reviewed, to assess radiologists" satisfaction with the program, and to examine case turnaround times. On average, about 50 teleradiology cases ate interpreted each month. Computed tomography (CT) cases are the most common type of case, constituting 65% of the total case volume. Average turnaround time (to generate a "wet read" once a case is received) is about 1.3 hours. Image quality was rated as generally good to excellent, and the user interface as generally good. Radiologists" confidence in their diagnostic decisions is about the same as reading films in the clinical environment. The most common reason for not being able to read teleradiology images is poor image quality, followed by lack of clinical history and not enough images. Copyright 9 1999 by W.B. Saunders CompanyT HE PRACTICE OF RADIOLOGY has been changing dramatically over the past few years. Teleradiology is becoming more prevalent as a means of reaching patients in rural areas. ~-3 As the practice of teleradiology grows, so does the need to maintain good quality control and assessment procedures. Some important aspects of quality control are: how quickly are teleradiology cases read anda report generated for the referring site, how confident are the radiologists in their diagnostic decisions, and how do the radiologists rate the quality of the images and the teleradiology system. The goal of this study was to assess these variables in the context of the teleradiology application of the Arizona Telemedicine Program. 4 The teleradiology program provides specialist support to rural hospitals and other radiology departments associated with the University Medical Center. Four sites in Arizona are currently supported with a dedicated teleradiology system: two local hospitals within the city of Tucson, and two rural hospitals in eastern central Arizona. Services include specialty consul- Telemedicine Network. Two of the dial-up sites will convert to high-speed transmission in the near future. In general, the residents in the Radiology Department do the wet read and provide an initial report for the referring site. Staff radiologists over read all cases and compile the final report. Teleradiology cases are read 24 hours a day, 7 days a week. Most cases are received in the evening and night hours, but a number of cases are received for interpretation during the day. MATERIALS AND METHODSTo evaluate turnaround times (time from receiving a case to the time a wet read is conducted), we examined the teleradiology log book kept by the department. This log book records every teleradiotogy case that is sent to the Radiology Department for consult, and includes the type of case, number of images, date, and time received. The date and time each case is read out is recorded on the wet read report form that is generated for each case and faxed back to the sending site. To evaluate how the radiologists feel about the teleradiology syste...

In this paper we describe our experience applying the Producible Adaptive Model-based Software (PAMS) technology to the development of safety critical flight control software. PAMS is based on the state of the art Model Integrated Computing (MIC) environment from Vanderbilt University and represents a highly evolvable model-based software development methodology and tool suite that is revolutionary in its ability to address software adaptation. In particular, PAMS is an adaptation framework that introduces support for model transformations, co-evolution of models and modeling tools, and self-adaptation of systems. Analogous to delayed binding in compiler technology, PAMS enables binding software updates statically at design-time, on a configuration basis at load-time, and dynamically at run-time. The focus of this paper will be the application of PAMS to designtime evolution.

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