Janice C. Honeyman

Teleradiology using switched dialup networks

A dialup wide-bandwidth digital teleradiology system is discussed. A laser film digitizer and a gray scale display system are used at Irwin and Munson Army Community Hospitals to digitize radiographic films and display digital images. A laser film printer at the University of Kansas Medical Center generates a film hardcopy of the transmitted digital data, and an interactive gray scale display is used to review the digital image data. The communication system consists of dialup switched multiple 56000 b/s digital channels, transmitting digital image data in parallel. Conventional radiographic films, multiformat camera films, and laser printed films from multimodality imaging systems have been successfully digitized, transmitted, and laser film recorded or gray scale displayed. It was found that the system provided clinically acceptable image quality reproductions. >

Information systems integration in radiology

Advances in information systems and technology in conjunction with outside forces requiring improved reporting are driving sweeping changes in the practice of radiology. In most academic radiology departments, there can be at least five separate information systems in daily use, a clinical picture archiving and communication system (PACS), a hospital information system (HIS), a radiology information system (RIS), a voice-recognition dictation system, and an electronic teaching/research file system. A PACS will have incomplete, incorrect, and inconsistent data if manual data entry is used. Correct routing of studies for diagnostic reporting and clinical review requires accurate information about the study type and the referring physician or service, often not easily entered manually. An HIS is a hospital-wide information system used to access patient information, reports from various services, and billing information. The RIS is typically a system specifically designed to place radiology orders, to receive interpretations, and to prepare bills for patients. Voice-recognition systems automatically transcribe the radiologist’s dictation, eliminating transcription delays. Another system that is needed in a teaching hospital holds images and data for research and education. Integration of diverse systems must be performed to provide the functionality required by an electronic radiology department and the services it supports. Health Level 7 (HL7) and Digital Imaging and Communications in Medicine (DICOM) have enabled sharing of data among systems and can be used as the building blocks for truly integrated systems, but the user community and manufacturers need to specify the types of functionality needed to build clinically useful systems. Although technology development has produced the tools for interoperability for clinical and research/educational use, more work needs to be done to define the types of interaction that needs to be performed to realize the potential of these systems.

Adaptive multiscale processing for contrast enhancement

This paper introduces a novel approach for accomplishing mammographic feature analysis through overcomplete multiresolution representations. We show that efficient representations may be identified from digital mammograms within a continuum of scale space and used to enhance features of importance to mammography. Choosing analyzing functions that are well localized in both space and frequency, results in a powerful methodology for image analysis. We describe methods of contrast enhancement based on two overcomplete (redundant) multiscale representations: (1) Dyadic wavelet transform (2) (phi) -transform. Mammograms are reconstructed from transform coefficients modified at one or more levels by non-linear, logarithmic and constant scale-space weight functions. Multiscale edges identified within distinct levels of transform space provide a local support for enhancement throughout each decomposition. We demonstrate that features extracted from wavelet spaces can provide an adaptive mechanism for accomplishing local contrast enhancement. We suggest that multiscale detection and local enhancement of singularities may be effectively employed for the visualization of breast pathology without excessive noise amplification.

Managing predefined templates and macros for a departmental speech recognition system using common software

The authors have developed a networked database system to create, store, and manage predefined radiology report definitions. This was prompted by complete departmental conversion to a computer speech recognition system (SRS) for clinical reporting. The software complements and extends the capabilities of the SRS, and 2 systems are integrated by means of a simple text file format and import/export functions within each program. This report describes the functional requirements, design considerations, and implementation details of the structured report management software. The database and its interface are designed to allow all radiologists and division managers to define and update template structures relevant to their practice areas. Two key conceptual extensions supported by the template management system are the addition of a template type construct and allowing individual radiologists to dynamically share common organ system or modality-specific templates. In addition, the template manager software enables specifying predefined report structures that can be triggered at the time of dictation from printed lists of barcodes. Initial experience using the program in a regional, multisite, academic radiology practice has been positive.

Mammographic image processing using wavelet processing techniques

Mammograms with masses corresponding to biopsy-proven cancer were processed using algorithms based on the wavelet transform. Five radiologists assessed the visibility of malignant masses in ten processed mammograms as compared with the original film images. Mammograms processed using these algorithms demonstrated some improvement in feature visualization. Wavelet-based methods of image enhancement could prove to be useful in mammography and merit further study.

Picture Archiving and Communication System (PACS) networking: Three implementation strategies

This paper outlines the diverse Picture Archiving and Communication Systems (PACS) networking implementation strategies at the University of California at Los Angeles, the University of Florida, and the University of Kansas. At the University of California at Los Angeles, a very high-speed network has been integrated into a hierarchical networking strategy, resulting in an entirely customized network for the local transmission of images. The University of Florida has chosen to implement networks for local transmission of images using commercially available equipment. The University of Kansas, specializing in teleradiology applications, uses commercial telecommunication circuits to implement long distance referral services to small hospitals.

Picture archiving and communication system bandwidth and storage requirements

The purpose of this work was to determine the requirements for image storage and network bandwidth for a total digital department in a moderate sized academic radiology department. Data from the radiology information system was combined with image production information to produce a model of image acquisition. Destinations of images to reading rooms were studied to determine the final distributions of film. All findings were used to model the flow of data that would be expected if the images in the department were completely digital. Using todays standards, the department would produce approximately 15.7 Gbytes of data per day or 3.5 Tbytes of data per year if all acquisitions were digital. The peak acquisition rate would be 1.8. Gbytes per hour with a sustained rate greater than 1 Gbyte per hour for most of the working day. The anticipated bandwidth for the total digital department exceeded the capabilities of the existing picture archiving and communication system equipment. A distributed networked archive solution was shown to optimized access to images by radiologists and referring clinicians.

A Cost-Analysis of Computed Radiography and Picture Archiving and Communication Systems in Portable Radiography

A total of 40,000 portable examinations are performed each year at Shands Hospital (Gainesville, FL), a 570-bed teaching hospital. Radiographs are obtained using a screen-film combination with the films digitized for transmission to displays in four intensive care units. A cost-analysis of replacing screen-film with computed radiography (CR) integrated into a filmless picture archiving and communication system (PACS) network was performed. Equipment requirements included two CR units, three high-resolution dual monitor displays, and an archive to store 3 months of image data. The capital costs were amortized over a 5-year period. Capital and operating costs of the proposed expansion to the existing PACS network, together with anticipated cost savings, were determined. The maximum data transfer rate for portable examinations was 150 MByte per hour and approximately 400 GByte of image data are generated each year. These figures were used to determine hhe hardware requirements for handling the acquisition, transfer, and display of the images. Annual costs of the proposed expansion were about

Nuclear medicine data communications

220,000. Cost savings were achieved by elimination of film, including its handling by technologists/library clerks, and amounted to about

Nuclear medicine PACS with an Interfile/ACR-NEMA interface and on-line medical record interface

200,000 per year.