James L. Lehr

COMPUTER ALGORITHMS FOR THE DETECTION OF BRAIN SCINTIGRAM ABNORMALITIES.

Abstract Algorithms for computer analysis of digitized brain scintigrams are described. A technique of variable thresholding and region enumeration is used to detect abnormalities which project clear of the calvarium, while a metric comparison detects distortions of the brain outline. The methods have been employed to process scintigrams digitized by means of an image dissector camera operating under control of an SEL-840A computer. It is felt that the algorithms will be equally applicable to brain scintigrams digitized by other means and that they may prove adaptable to the analysis of other organ system images.

Radiate—Updated and Redesigned for Multiple Cathode-Ray Tube Terminals

The concept of a computer system for on-line, real time synthesis and transmission of radiological consultations has been described (6, 7). Automatic coding and storing of the radiological report is a by-product of this system. Dictionaries for diagnostic examinations (240 entries), anatomic sites (1,007 entries), and diagnosis (1,354 entries) have been developed and expanded. Initially, a typewriter type terminal served to interface the computer with the radiologist. Now, a cathode-ray tube (CRT) with alphanumeric keyboard gives the radiologist the ability to seek, receive, acknowledge, or alter information from the computer memory or the established data base. During the past three years RADIATE has been broadened and tested on various computers on a research basis. Recently the system, though unchanged in basic concept, has been completely redesigned for the IBM 360 Series computers so that greater flexibility and faster information transaction could be achieved. The present RADIATE system provides for...

Impact Of Manual And Computer-Assisted PACS For Automated PACS

Considerations of totally electronic picture archiving system (PACS) often neglect the fact that every radiology practice currently has some system for storing and retrieving images and related alphanumeric data. Although these systems are usually manual, many departments now use on-line computers to help manage film flow. In either event, the creation of electronic PACS can be viewed as a classic data processing problem of automating an existing system, and the conversion should proceed through the usual steps of documenting the existing system in detail, and conducting feasibility studies and cost-benefit analyses. Documenting current systems should be facilitated by computer-assisted PACS - particularly documenting transaction volumes which can be provided as a by-product of radiology information management systems. Similarly cost-benefit analysis should be facilitated, although the cost/benefit ratio may be less favorable when comparing automated to computer-assisted PACS. Finally, information management features such as those provided by current on-line radiology systems provide a framework necessary to realize the full benefits of automated PACS.

Overview Of ACR-NEMA Digital Imaging And Communication Standard

This presentation is to outline the American College of Radiology (ACR) and National Electrical Manufacturers Associa-tion (NEMA) Digital Imaging and Communica-tion Standard (ACR-NEMA Digital Imaging and Communication), which is a creation of joint effort of many fine knowledgeable people on the ACR-NEMA Digital Imaging and Communication Standards Committee, especially Allen Edwin and Gwilym Lodwick, Co-Chairman and Laura Murphy, Executive of the Committee. We hope that the ACR-NEMA Standard will be useful in the development of digital diagnostic imaging and medical information.

The ACR/NEMA Standard Data Dictionary: A Radiologist's Perspective

The ACR-NEMA Standard provides mechanisms by which a considerable amount of non-image information can be transmitted along with an image. Much of this information is similar to data currently managed by radiology information systems. However, the Standard does not provide methods by which the accuracy and consistency of these data can be maintained at a level that makes them usable for such important functions as billing or statistical analysis. A strategy by which extended versions of existing radiology information systems can be implemented with an ACR-NEMA-compatible PACS to provide data accuracy and consistency is discussed. The Standard also provides a mechanism to transmit the location and orientation of planar cross-sectional images. This will simplify obtaining measurements such as those necessary for stereotoxic techniques in CT, MRI or PET. However, the mechanism is not adequate to deal with the geometrical complexities of projection images. This creates an awkward situation for localizer images in CT and MRI. Extending the Standard to deal with projection images would not only remove this defect but also encourage the development of new quantitative applications in digital radiography.

Update Of The ACR-NEMA Standard Committee

In January, 1984, the American College of Radiology (ACR) representing the users of imaging equipment and the National Electrical Manufacturers Association (NEMA) representing the manufacturers of imaging equipment joined forces to create a committee that could solve the compatibility issues surrounding the exchange of digital medical images. This committee, the ACR-NEMA Digital Imaging and Communication Standards Committee was composed of radiologists and experts from industry who addressed the problems involved in interfacing different digital imaging modalities. In just two years, the committee and three of its working groups created an industry standard interface, ACR-NEMA Digital Imaging and Communications Standard, Publication No. 300-1985. The ACR-NEMA interface allows digital medical images and related information to be communicated between different imaging devices, regardless of manufacturer or use of differing image formats. The interface is modeled on the International Standards Organizations Open Systems Interconnection sever-layer reference model. It is believed that the development of the Interface was the first step in the development of standards for Medical Picture Archiving and Communications Systems (PACS). Developing the interface Standard has required intensive technical analysis and examination of the future trends for digital imaging in order to design a model which would not be quickly outmoded. To continue the enhancement and future development of image management systems, various working groups have been created under the direction of the ACR-NEMA Committee.

Do’s and don’ts of installing a RIS

This report reviews several important issues relating to the acquisition of a radiology information system (RIS). It emphasizes the importance of defining specific goals for computerizing a department and for understanding that department’s manual operations. It then outlines methods to request proposals from prospective vendors and to evaluate their responses. Suggestions for negotiating a favorable arrangement with a vendor follow. Finally, the summary lists five do’s and three don’ts for selecting and installing a RIS.

The Acr-Nema Exchange Media Standards: Progress And Future Directions

Working Group V of the ACR-NEMA Digital Imaging and Communications Standards Committee has developed a standard for the exchange of ACR-NEMA formatted data on magnetic tape. This standard makes use of the message structure provided in the ACR-NEMA Digital Imaging and Communications Standard (NEMA 300-1985), and formats it in an ANSI standard label and file structure so as to be compatible with one-half inch magnetic tape systems and software which comply with the ANSI standards. The ACR-NEMA magnetic tape standard has evolved since the preliminary information was presented at the SPIE Medicine XIV/PACS IV in 1986. At present, the standard has been circulated for comment, and will soon be balloted. This paper will present the magnetic tape standard in its final form and will also discuss the future direction of the Working Group. The Working Group is strongly considering the use of a media-independent standard for use with the ACR-NEMA message structure so as to accomodate a diverse set of exchange media.

The ACR-NEMA Magnetic Tape Standard

The ACR-NEMA Digital Imaging and Communications Standards Committee has published its Standard for an interface to medical imaging equipment. Various groups are now working on implementing this Standard, and the need for an exchange medium other than the electrical one of the Standard was forseen as necessary for software development. Working Group V was formed to examine this issue, and proposed to work first on a magnetic tape standard as magnetic tape drives are present on many imaging devices. The message format of the Standard was felt to be readily adaptable to magnetic tape. The physical specification has been chosen to conform to the ANSI standards for unrecorded and recorded magnetic tape, The logical specification is being developed with an attempt to adhere to the ANSI Standard for Magnetic Tape Labels and File Structure (1). This paper will discuss the reasons for developing a new format instead of using existing image interchange standards, explain the need for, and problems raised by tape directories, and explain the tape Standard as it currently exists.

Comparison Exam: Impact On PACS

Reviewing previously acquired images of a patient when interpreting newly acquired ones is an important aspect of clinical radiology that has received relatively little attention in specifying requirements for automated picture archiving and communications systems (PACS). This paper examines reasons that reviewing comparison images plays an essential role in radiology, and it attempts to describe the range of policies currently employed by radiology departments. Data acquired from the use of the Missouri Automated Radiology System (MARS) at the University of Chicago are presented to quantify the number of comparison examinations that exist in this patient population. The implications of storing, retrieving and displaying these comparison images are discussed under different policies for both current film file systems and PACS.