Systems simulation - the art and science

The authors investigate whether data representing medical image sequences can be compressed more efficiently by taking into account the temporal correlation between the sequence frames. The standard of comparison is intraframe HINT, the best-known reversible decorrelation method for 2-D images. In interframe decorrelation, a distinction is made between extrapolation- and interpolation-based methods, and methods based on local motion estimation, block motion estimation, and unregistered decorrelation. These distinctions give six classes of interframe decorrelation methods, all of which are described. The methods are evaluated by applying them to sequences of coronary X-ray angiograms, ventricle angiograms, and liver scintigrams, as well as to a (nonmedical) videoconferencing image sequence. For the medical image sequences: (1) interpolation-based methods are superior to extrapolation-based methods; (2) estimation of interframe motion is not advantageous for image compression; (3) interframe compression yields entropies comparable to intraframe HINT at higher computational costs; and (4) two methods, unregistered extrapolation and interpolation, are nonetheless possibly interesting alternatives to intraframe HINT. >

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Reversible interframe compression of medical images: a comparison of decorrelation methods

The effective delivery of health care has become increasingly dependent on a wide range of medical data that includes a variety of images. Manual and computer-based medical records ordinarily do not contain image data, leaving the physician to deal with a fragmented patient record widely scattered throughout the hospital. The Department of Veterans Affairs is currently installing a prototype hospital information system workstation network to demonstrate the feasibility of providing image management and communications functionality as an integral part of an existing hospital information system. The core of this system is a data base management system adapted to handle images as a new data type. A general model for this network-based integration is discussed and various alternative architectures are examined.

https://link.springer.com/content/pdf/10.1007%2FBF03170416.pdf

Integrating medical images into hospital information systems

A Second Generation PACS Concept

Image compression by vector quantization: a review focused on codebook generation

The existence of a link between a HIS, incorporating a RIS, and a PACS is one of the most indispensible prerequisites to perform a clinical evaluation study of a PACS in practice. The two main reasons for realizing a IIIS-PACS coupling are concerned with 1) proper image management e.g. in order to achieve acceptable waiting times and 2) the user need of having all patient relevant data available in the same workstation. A first phase coupling between an existing HIS and a just installed PACS has been realized by BAZIS in the Utrecht University Hospital in the Netherlands. These activities were carried out as part of the Dutch PACS Project, a collaboration in the PACS field of BAZIS, the Utrecht University Hospital (AZU) and Philips Medical Systems. For the first phase only HIS data of the in-patients of one particular ward of Internal Medicine were transmitted using a one-way dataflow (from. HIS to PACS). In phase two the coupling will he hi-directional and more departments will be part of the experiment. In phase three of the coupling project a more general. HIS-PACS interface will be developed, independent of the HIS and PACS manufacturers. In April 1988 the first public data exchange (patient data, order data, reports) between the BAZIS/ZIS and Philips/MARCOM system has been demonstrated. This was the first working example of a HIS-PACS coupling worldwide to our knowledge. This paper gives an overview of the experimental set-up, the demonstration during the 6th EuroPACS meeting , the results and problems encountered thusfar and statistical data from daily practice.

HIS-PACS Coupling In Practice

One of the major bottlenecks in realizing a full size PACS is the image storage component. Further technological developments are necessary before sufficient capacity can be realized. It can be expected that a multi-layered storage structure will be necessary where large capacity with relatively long access times will be offered at the lowest level. The higher levels will show decreasing access times combined with decreasing capacity. Both in the judgement of images acquired in the diagnostic study and in the work of the clinician historical images of the patient concerned may be needed. If these images had to be retrieved from the lowest storage level at the moment they are needed, the service time would definitely be unacceptable. So a strategy is necessary for the anticipation of the need of access to images. In this paper a first attempt is made to identify relevant parameters to be used in such a look ahead algorithm for the activation of images to a next level. A simple algorithm is suggested; the need for further study is emphasized.

Considerations On An Algorithm For Activation Of Images In A Multi-Layered Storage System Within A PACS

In modern hospitals the attention paid to the problem of lending and archiving of images is increasing. In almost every (big) hospital complaints are heard concerning missing X-ray images and lack of storage space. The use of the computer and digital storage systems might lead to a solution of these problems. However enormous amounts of data are involved, ranging per image from 128 kbytes for a CT-scan to over 2 Mbytes for a thorax X-ray. For the Leiden university hospital (940 beds) this implies a daily production of about 8000 Mbytes of uncompressed data after digitisation. At this moment, a study is in progress carried out by the central development organisation (BAZIS) of a group of Dutch cooperating hospitals, aiming at a well founded choice of a system framework. During this study extensive use is made of the information available from the existing Hospital Information System (HIS). The acquired data will be used as input to a simulation model, which should give more insight into the behaviour and necessary characteristics of the memory configuration required. This configuration will consist of different layers.

A Layered Storage Structure For Images Confronted With The Use Of X-Ray Images In A Hospital

This paper gives a brief overview of PACS, including the basic components of a PACS system and what operations are or should be provided by it. This includes as well, a discussion of desired response time.

A. R. Bakker

Papers

HIS-PACS Coupling In Practice

Considerations On An Algorithm For Activation Of Images In A Multi-Layered Storage System Within A PACS

A Layered Storage Structure For Images Confronted With The Use Of X-Ray Images In A Hospital

Introduction to Pacs for Those Interested in Image Processing

Top-down design of a picture archiving and communications system (PACS) by means of simulation.