24   MeDiMed

The following terms, not too common in the ICT field, should be introduced here:

24.1   Introduction

The Institute of Computer Science at the Masaryk University has been cooperating closely with Brno hospitals in implementing information and communication technology in the field of taking, transporting, archiving and presenting digital picture medical data since 1999. This cooperation consists of activities and projects whose goal is a development of a metropolitan archive of medical imaging information obtained from hospital modalities, diagnostic equipment like ultrasound (US), digital mammograph (DMG), computer tomography (CT), magnetic resonance (MR), etc., as well as providing access to this archive via computer network. The goal is to improve the quality of medical operations and common medical care and to enhance the environment for medicinal research and student education by using an up-to-date information technology and medical informatics.

The project includes support of imaging data transfer between individual workplaces or hospitals which a patient visits during his/her treatment, including optional consultations by remote specialists. As a result, correct diagnosis is easier and faster to achieve, repeated checkups are eliminated, time is saved for both the patient and doctor which saves finances as well. This project can also be regarded as a pilot project for other regions in our country.

24.1.1   Recapitulation

At the end of 1999, a PACS system was purchased for real-time processing, transfer and archiving of imaging data (both static and dynamic) as a basis for the archive. In the same year, first ultrasound modalities were connected to this system. These were the workplaces within the Brno Faculty Hospital (Obilní trh - Maternity Hospital and Černopolní - Paediatric Hospital) to allow consulting the ultrasound checkups by physicians specialised in prenatal (intrauterine) diagnostics of foetuses as well as diagnostics of new-born children's organs, especially cardiologic. Data between these locations are transferred using dedicated fibres of the Brno Academic Computer Network.

Originally, the ultrasound systems used in these locations provided analogue output only; therefore, converting the analogue output to the DICOM format was necessary. During the year 2000 we learned about the properties and limitations of the installed PACS system. The system underwent various modifications according to practical usage requirements and an imaging database was being built gradually.

One of the first key results of this project was an agreement reached among all collaborating subjects on the necessity of using the DICOM standard. Afterwards, all diagnostical equipment purchased later was DICOM-conformant. In the second half of 2000, a magnetic resonance equipment located in the St. Anne University Hospital was connected to the system. This MR equipment has already contained the DICOM output. Several other DICOM-conformant modalities belonging to the Masaryk Memorial Cancer Institute were connected in 2001. These were: a digital mammograph, computer tomograph and three ultrasound devices.

24.1.2   Research fields

The complex solution of building the metropolitan archive of medical imaging information and its usage covers three basic fields: legislative, technological, and financial.

In the legislative field the key problem is securing the medical information from any abuse. This is a very sensitive problem which is scrutinised very closely by the hospitals, and the rules for securing the data both in its origin and during its transport and archival are very strict.

Because the solution of this problem could not be solved just within the scope of our project but on the other hand it was a precondition for its further development, a meeting of directors of all Brno hospitals, deputy mayor of Brno, rector of the Masaryk University, a representative from the Ministry of Health care as well as a representative of the project team from the Masaryk University Computing Centre which coordinates all activities concerning the archive project. On this meeting, basic principles were agreed upon and this allowed further coordinated development of this system.

The field of technology covers research and implementation of practical solutions in two subareas regarding the hardware and usage of the whole archiving system.

The first subarea deals with proper data archiving: archive server and its safe operation, as well as selection of archiving media with respect to their cost, functional parameters and capacity. Problems of data rate, security and reliability of network transmission, access rights etc., also belong to this subarea.

The second subarea covers video display devices. One understands that different equipment parameters may be required depending on modalities used; in general, they may differ significantly from those common in other fields. E.g., sharpness of displays necessary for the field of magnetic resonance is so high that it touches (or surpasses) the technical limits of contemporary display units. This applies, e.g., to the flat panel displays commonly available.

The Financial subarea includes search for financial resources for the system (in budgets of participating hospitals as well as in domestic and international grant programmes), but also search for a balance between requirements, technical facilities and solution costs in particular areas of deployment.

Very close collaboration with medical specialists is necessary for success because only they are able to tell which display units are appropriate and sufficient for a given purpose and modality. For example, ultrasound - unlike magnetic resonance - does not require high-quality (and costly) monitors. A similar problem is selecting an optimum archiving method which allows immediate access to stored data: depending on the modality, one checkup may generate several, tens or hundreds of images.

24.1.3   The central archive

A remarkable goal reached in 2001 was the central archival server site built in a secure area of the new ICS MU computer room at Botanická 68a street (the computer room itself with this site was officially opened on December 6, 2001). To reach a maximum physical security of sensitive data on our servers and data storage devices, this site was installed in a standalone, separate and locked section of the computer room. This site allows interconnection of diagnostic modalities located in Brno hospitals; at the time of writing this article it contained graphic documentation consisting of 980,000 images. All checkups produced 1.3 TB of data stored on 300 DVD discs of the long-term archive.

The central archive site consists of the following equipment:

24.1.4   Display devices

In parallel with development and operation of the PACS archive, evaluating the quality of available display devices is under way. For objective evaluation, a sufficient data quantity must be obtained first; this will be available only after more modalities of different types are connected during the current and next year.

Our experience confirms that an universal type of display devices or display software suitable for all modality types and areas of their use does not exist currently. In some special cases (e.g., tomography pictures of brain structures), properties of contemporary digital displays fall behind the classical snapshots.

However, the problems to be solved are not only technical: another obstacle is an inertial and conservative attitude, distrust and inflexibility of some medical specialists.

24.1.5   Current fields of collaborations

Based on practical experience, these seven partial medical applications from various medical fields were included in the metropolitan PACS archive activities:

Magnetic resonance in the Masaryk Memorial Cancer Institute (MMCI)
Transfer of MR checkup results from the St. Anne University Hospital to the MMCI radiology clinic and archival of images in context of CT diagnoses.
Mammodiagnostics
Transfer of breast DMG and US images from the MMCI to the St. Anne University Hospital, Department of Oncology.
Breast diagnostics at the MMCI
Electronic archival and transfer of selected patients' graphic documentation (studies and presentations) of the MMCI Radiology Department which includes the DMG, CT and US investigation.
Brain diagnostics at the St. Anne University Hospital
Electronic archival and transfer of graphic documentation of the central nerve system pathology (studies and presentations which include the CT, MR and AG checkup results) from the St. Anne University Hospital, Department of viewing methods. These images are shared electronically with the Departments of neurosurgery, radiation oncology and neurology of this hospital.
Paediatric oncology
Electronic archival of all paediatric oncology patients' checkup results (especially X-ray, CT, MR, AG and histology) including those found in the hospital information system, which can be shared electronically or transferred to other departments of paediatric oncology in the Czech Republic.
Neonatal cardiology
Electronic archiving of US images of newborns' heart defects which can be exported and consulted with the cardiosurgery department experts.
Pathology
Development of consultations network of pathology specialists - transport of images for consultation and second opinion between pathology specialists of member hospitals - including transfer of complex graphic documentation of selected patients.

24.1.6   Project technical solution

First medical images were transferred using a completely standalone network interconnecting only the PACS server and appropriate modalities. This solution provided a very easy solution of both security and IP addressing network plan. After these first steps we moved forward to a production environment; as a result, a need for accessing the PACS from ordinary hospital workstations in the internal hospital network followed. A problem with IP addressing followed because the private address spaces of participating hospitals overlapped. Another problem was the security of the central PACS archive. Both problems were solved by deploying NAT firewalls. An interconnection diagram of Brno hospitals is shown on the Figure.

[Figure]

Figure 24.1: Interconnection diagram of Brno hospitals

Central PACS servers are separated from the carrier infrastructure by a firewall. In addition to traffic filtering, this firewall also translates the IP addresses of central PACS servers. Therefore, each hospital can see these servers having an IP address belonging to its own address space.

Another NAT firewall is connected to the hospital network; its output is connected to the hospital border router. This ensures both the PACS system security (this firewall is under control of the MU ICS) and the hospital internal network protection from potential mistakes on our side (all traffic passes through a router under control of the hospital network specialists). This solution allows accessing both the PACS archive system and the Internet from the same user station at the same time. The hospital firewall translates the hospital IP addresses of workstations and modalities to another address space which does not overlap with that of other participants or servers.

24.2   Project progress in 2003

24.2.1   Related projects

In 2003, research and implementation of the PACS system development continued. The first part of system implementation was supported by a Ministry of Education grant project. Its main goal was to obtain authentic information on necessary bandwidth, volumes of stored data, experience with image processing, image information system features, possibilities and limitations of connecting various information resources (US, CT, MR, etc.).

The second part, funded by the Ministry of Health care grant agency, was oriented towards obtaining information about separate modalities' requirements for bandwidth and response time during routine operation, radiologists' experience with display monitors including the selection of a suitable viewer for education purposes, etc. Gradually, all of the Brno hospitals joined this project: they are connected to the central PACS archive via dedicated fibre optic lines in a star-shaped topology for security and speed. This topology diagram is shown in Figure.

[Figure]

Figure 24.2: The Brno Optical Academic Computer Network (large image)

Currently, CESNET, z. s. p. o. is significantly participating in these activities. The main reason is that other organisations outside of the Brno region connect to the metropolitan PACS archive. This brings rather high requirements on the quality of data links as well as several other problems which our project must solve. The goal is getting experience with transferring large data volumes among various modalities and remote locations over public data network where appropriate security measures must be taken using encryption and other technologies.

24.2.2   Extending beyond the Brno region

We started connecting the extra-Brno participants in 2003. The principal problem for remote hospitals is getting sufficiently fat data pipes for communication with the central PACS servers located in Brno.

The optimum solution is using the CESNET2 National Research and Education Network. This network provides sufficient bandwidth for transferring medical images. The only problem remaining is the security of transferred data. To solve this, we decided to use IPSEC tunnelling which is implemented using the Cisco PIX firewalls. On the MU ICS side, a PIX 525 is used to terminate the IPSEC tunnels from remote hospitals; it is connected to the firewall separating the PACS servers from the rest of the network. On the remote hospital side, a PIX 515E is used. Its functions are the IPSEC tunnel termination as well as network address translation and filtering the traffic between the hospital and PACS. Currently, the 3DES encryption algorithm is used; in near future, the AES algorithm should be used. A general diagram of extra-Brno hospital connection is shown in Figure.

[Figure]

Figure 24.3: Interconnection diagram of extra-Brno hospitals

In the beginning of 2003, a hospital in Kyjov, a South Moravian town, was connected to the PACS via the CESNET2 network at a 10 Mbps speed. At the same time, two display monitors were installed in this hospital allowing viewing images from this hospital's own CT as well as communication with collaborating Brno hospitals. The Kyjov district hospital is not using our PACS system for long-term archival currently but gradually, it is getting to participate in the interchange system of medical image information exchange.

The experience we had gained while connecting the Kyjov hospital became useful for connecting the hospital in Jihlava, another Moravian town. This hospital is connected via an 8 Mbps leased line. This bandwidth is not quite sufficient because this hospital stores all of its images in the central PACS archive in Brno. Therefore, a faster link using the CESNET2 network is being discussed.

All routine operation of this hospital is dependent on the central PACS system. The Jihlava hospital was equipped gradually with six diagnostic stations which can process the X-ray images as well as interchange this information with hospitals in Brno. Long-term archival is provided for the Jihlava hospital by the PACS system and we are ready to help it with eventual transition to a fully digital image processing.

24.3   Expected development

The work planned for 2004 can be divided to the following areas: connecting more participants, upgrading the network bandwidth and improving the system reliability.

24.3.1   Connecting more participants

Several new hospitals are interested in participation in our PACS system. As soon as an appropriate data link is available, the IKEM health care institute in Prague should be connected using the CESNET2 network. From the security point of view, this connection will be equivalent to using a public data network; therefore, data encryption will be necessary.

The data link used for connecting the Jihlava hospital is of insufficient bandwidth. As the bandwidth upgrade of long-distance lines is expensive, we expect that the Jihlava hospital will also use the CESNET2 network for its connection to the PACS system. The proposed topology is illustrated in Figure.

[Figure]

Figure 24.4: Connection of individual project participants

24.3.2   Reliability improvement

With respect to growing utilisation of the central PACS system and expected participation of more hospitals and health care organisations in Brno and elsewhere, improved reliability of both the PACS system itself and networking infrastructure is necessary. Reliability of the PACS system itself will be improved by building a backup PACS centre: this backup site will be situated in the Comenius Square where the university central computer hall open 24 hours is located. To minimise system downtime caused by software failures, the backup PACS system will run a different software. Data interchange between the primary and backup centre will be based on the DICOM standard.

To improve reliability of networking infrastructure, we plan to build independent fibre optics links from all Brno hospitals to both the primary and backup centres. This solution is possible owing to our own large fibre optics network. The planned topology is shown in Figure.

[Figure]

Figure 24.5: Logical network topology after the backup centre is built

The situation of health care institutions outside Brno is much more difficult. Deployment of two independent leased data links of sufficient bandwidth is too expensive. This is why we plan testing the backup capabilities of a number of dialup lines where traffic will be split in parallel. This solution will require also some kind of control provisions: as the backup connection will provide a smaller bandwidth than that of the primary data link, a suitable method for image transfer must be found so that this data will be available on a local caching system before the medicians need it.

24.3.3   New applications

In cooperation with the Multimedia transmissions project we plan to study the feasibility of on-line voice and video communications of the PACS users. We assume that we will be able to support remote consultations concerning the images stored in PACS.

24.4   Results

All of the above mentioned activities allow or will allow increasing the number of health care organisations participating in the PACS system. This will increase the amount of stored information for scientific and research tasks and of course for improvement of medical student education.

Lessons drawn from selected applications and general solutions applied in the MeDiMed project have been published and presented at domestic and foreign conferences. Publications are listed in the Appendix of this report.

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