Creation of a Radiological Image Library

Ralph Lawson-Smith, Division of Imaging, Westmead Hospital

Morris Ross, Information Services Western Sydney Area Health Service

Introduction

Westmead Hospital is one of seven hospitals forming the Western Sydney Area Health Service. It is also a major teaching hospital for the University of Sydney and, as such, reviews the effectiveness of its teaching methods regularly.

Background and problem

The traditional method for radiological teaching of medical and postgraduate students using images was that documentation was prepared for each film and attached to the bag containing the X-rays. The films were copied and distributed to the teaching centres

The problems with this approach were:

the preparation was time consuming;
the preparation was labour-intensive, and costly;
maintenance of teaching files at each facility was labour-intensive, time consuming and expensive;
only one copy of a film was available at each clinical school;
the cases tended to deteriorate over time with handling;
class sizes were limited as a result of limited available material; and
private study by students was very limited.

A different approach towards teaching within the Radiology discipline was required which offered:

easier preparation of teaching files;
reduced costs in preparation;
reduced costs in administration and maintenance of problems at each teaching centre;
availability of problems to ALL students;
improved quality of teaching by increasing the number and availability of problems to each student;
greatly increased cost effectiveness ;
options for new techniques of teaching.

The options explored had to be able to meet the following criteria:

no limit on class sizes;
option of private study available to all students;
quality of teaching results at least comparable with existing methods;
no increase in the costs of problem preparation;
"capped" costs for problem preparation in the future;
offer options for other teaching alternatives; and
make use of existing technology to package the disparate media involved in the teaching problems.

Method

We decided that we should establish a website at Westmead and use existing Web technology to deliver our cases.
To set up a WWW site at the hospital we needed:

Server
Film digitiser/scanner
Image manipulation Software
Database software
Access to the Internet
HTML editing facilities
Manpower

Server selection

The Issues

The decision to install a Web Server at Westmead posed a number of problems:

Security

World-wide access to a Web server could compromise the integrity and security of the Westmead Hospital computer network.

Operation

Support for operation of network Servers within WSAHS was focused primarily on Novell. Web Server operation and experience throughout the world appeared to be mainly UNIX-based, with some use of Windows NT. Almost no one was using Novell as a base for Web operation. Communication lines into Westmead were restricted in bandwidth. For the chosen solution to work, it was realised that it had to be able to fit into the normal operational culture within Westmead.

Storage

Westmead Hospital has a large film library of approximately 4,000 "interesting" cases . There would be 10,000 images associated with these cases. We also have 1,000 teaching cases available to medical students and the University has over 100 teaching cases. To make best use of these resources the information needs to be available on computer

Images take up an extraordinary amount of storage space. A chest X-ray can be 5Mb when scanned and up to 25Mb if collected electronically from the PAX network. The storage needed for these images is in excess of 50Gb and as the library grows more storage will be needed.

Access

Another problem that we have is that not all students have full Internet access. The Hospital has only a class C licence (255 Addresses) so some system of sharing IP addresses has to be considered.

The Proposal

It was decided to install a Web Server at Westmead, with the following characteristics:

Novell operating system -- this ensured that the system would operate effectively on the WSAHS network, with support from the existing network technicians
Mirror site established at Sydney University -- this allowed world-wide access to the material on the Server, without allowing "foreign" users on our network. It also ensured that the communication lines into Westmead were not impacted.
Installation of a Server with moderate processing speed, with large capacity, high availability disks.

The selection of the server hardware and software was one of the most difficult procedures of the whole process. As we were complete novices in the Web we had to rely on other people's expertise. Our requirements were:

Large storage capacity (16Gb+)
Short access times
Ease of set-up and maintenance
Reliability
Compatability with the existing WAN and ISD Requirements

Intially we looked at Unix, MacIntosh and PC-based systems.

A Unix system would have done the job very well. However, there is very little Unix expertise in the Hospital and none in the set up group. As there are many flavours of Unix, this selection itself would be a big job.

Macintosh was considered but again there was little expertise in the hospital and possibly a personal bias against blackbox technology.

The third alternative was a PC based server running under Novell 3.12 using an NLM Web server. This was the final decision as this was the system that we had the most experience with and in which our Information Services Department (ISD) has considerable expertise.

The installed Server had the following configuration:

Compaq ProLinea Server -- Pentium 75
64Mb RAM
16 Gb hard disk -- "hot swappable" drives (RAID configuration with 5 x 4Gb drives -- this has proved useful with failing drives, as they can be replaced without interruption to the Service)
GLACI-HTTPD Web software for the Server

The server was installed in a rack mount and placed in the data centre. All routine maintenance of the server is conducted by ISD.

The Web server we intended to use was the GLACI-HTTPD v1.04 from The Great Lakes Area Commercial Internet, however this has proved less than satisfactory. The security features did not work, there is no ability to write CGI programs and back-up from the company has been less than satisfactory. It is possible that the system will be reconfigured to run Windows NT and a Windows based server or we will use the new server recently released by Novell. At present we are running as a mirror site based at Sydney University. Unfortunately this site does not lend itself to CGI database access.

Image Scanning and Storage

Current images in the library are stored on film and have to be scanned and stored as an image file. A Rayven X-ray scanner was purchased for this purpose. All the images are scanned at the maximum resolution and saved initially as TIF files. These images are later manipulated in consultation with a Radiologist and stored as JPG images. As the images are for teaching purposes they can be stored compressed. Compression ratios of 15 to 1 have been achieved with no discernable loss of image quality.

Accessing the information

Initally, each case was marked up individually with images scanned and the text written specifically for the web. This, however, proved too time consuming as each case took over a day to mark up.

We did however have a large number of registrar teaching cases with documentation already prepared. This information could be easily entered into a database and mark-up done with the use of CGI scripts.

A Microsoft Access database was created to handle the information for each case. This system has been in use, for all new cases, for the last 12 months with a hard copy of the information being pasted to the outside of the film storage bag. Information is also being entered retrospectively for the older cases.

The database has the following fields:

ID Unique ID
ACR _NO American College of Radiologists diagnosis code
DIAGNOSIS Diagnosis
AGE Age
SEX Sex
PREPARED BY Doctor preparing information
CLINICAL DETAILS Clinical information
RADIOLOGY Radiological findings
DISCUSSION Case discussion
REFERENCES References to clinical texts
IMAGE1 File name of the First image
IMADGE1D Description of first image
IMAGE2
IMAGE2D
IMAGE3
IMAGE3D
IMAGE4
IMAGE4D
IMAGE5
IMAGE5D
IMAGE6
IMAGE6D

Each case can have up to six images with the file name and brief description (up to 255 character) stored in the database.

Temporarily all CGI scripting is being developed on a DOS machine using a Windows httpd (Windows version is V1.4c). This package, "Windows httpd", was developed by Robert B.Denny. The CGI scripts are written in Visual Basic and must run in a Windows environment. Provided with the server is a Visual Basic script to interpret form data (CGI.bas). There are three separate parts to retrieving data from the Access Database.

Setting up the queries inside the database and initialising the parameters to be sent from Visual Basic.
The Basic coding that interrogates the database and returns the info to the Basic program.
The Basic routine that returns the information to the server in a HTML format.

At present we have routines that will search the database by ACR code and by subject. We plan to expand the search ability greatly perhaps even to searching for text strings in the diagnosis or radiology fields. The only limitation on our searching ability is whether it is useful to search those fields.

Security

Security is an ongoing problem in a hospital environment. To allow unrestricted access to the hospital's WAN would be irresponsible owing to the nature of the information contained thereon. The concept of restricting information is against the spirit of the web but in our case is essential for the working of a Hospital.

When the site is fully functional, it will be protected by a firewall and the onsite server will only accept requests from the IP addresses available to hospital staff and students. The site will continue to be mirrored at Sydney University.

Samples

Chest

Paediatric

Genitourinary Tract

Musculo- skeletal

Current stage

We have been able to establish a small but growing library of cases for publication on the Web. These cases cover a broad range of topics of interest to Registrars and medical students. As well, we are building a library of X-ray images suitable for inclusion in the problem based learning medical course to be introduced in 1997.

Discussion

We have found that this is a very effective way of making images available. The access times from our internal server have been quite satisfactory for teaching. This is quite an important feature as 30-40 sec waiting in front of a screen seems an age. However there have been some unexpected problems:

The scanning of films has been much more complicated than expected.
The area of interest on each film had to be identified.
Each X-ray had to be individually manipulated for contrast and brightness.
All films had to be checked and "tweaked" by a radiologist before final compression into a JPG format.

Future

The growth potential for the project is enormous. We hope to use multimedia to enhance our teaching files, including sound for better description and to cover loading delays. Some of the more recent techniques in imaging are dynamic and a video image could simply and cheaply present this to students.

There is also the potential to set up a newsgroup-like function to allow discussion between students about various cases and to allow input from radiologists about the films; almost like an on-line tutorial.

As the project progresses, there will be a growing database of images and other material to use as a resource for the problem-based learning teaching methods being adopted at Sydney University.

Copyright

Ralph Lawson-Smith & Morris Ross © 1996. The authors assigns to Southern Cross University and other educational and non-profit institutions a non-exclusive licence to use this document for personal use and in courses of instruction provided that the article is used in full and this copyright statement is reproduced. The authors also grants a non-exclusive licence to Southern Cross University to publish this document in full on the World Wide Web and on CD-ROM, and for the document to be published on mirrors on the World Wide Web. Any other usage is prohibited without the express permission of the author.

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