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System requirements, the use of telepathology in diagnostic pathology and its application to quality assurance programmes
Current Diagnostic Pathology (1997) 4, 65-72
9 1997 Pearson Professional Ltd
Mini-symposium: Telepathology
System requirements, the use of telepathology in diagnostic pathology and its application to quality assurance programmes
C. S o w t e r and C. A. W e l l s
INTRODUCTION
system is dependent on its application, the basic system can be considered as four component groups: hardware, software, the user interface, and the user. This review will explain, in general terms, the setup, implementation and the application of telepathology systems to pathology. Only the use of telepathology for breast quality assurance will be discussed in detail.
The concept of using video microscopy to provide diagnostic services to remote locations was first described in the USA in 1968, when monochrome images were transmitted in real time. The communication protocol was a dedicated point-to-point microwave link. Eighteen years later, in 1986, a prototype commercial system using colour images, computer controlled microscopy, highdefinition television and satellite communication was described. It was not, however, until 1990 that a commercial telepathology system became available. I Since 1990, the development of telepathology has led to its routine use in some countries. There are no technological problems to be solved. The high-speed communication costs needed for remote diagnosis and remote consultation are, however, very expensive. These costs are a major obstacle to the routine application of telepathology within the UK. The multimedia computers now available at very low prices can be used as the basis of telepathology systems. Such systems can be used for remote consultation of experts or consensus diagnosis using microscope teleconferencing. Both require real-time performance. Other applications such as quality assurance, continuing medical education (CME) and teaching do not need a realtime capability and the lower purchase and running costs of such telepathology systems should make them cost effective. Telepathology should help to streamline quality assurance and improve diagnostic accuracy. Although the exact specification of a telepathology
I N T E R N A T I O N A L I N T E R E S T IN TELEPATHOLOGY Some pathologists believe that telepathology is too expensive and that it does not have a useful role in routine pathology. However, there has been increasing interest in its use throughout the world. In 1992, the 1st European Symposium on Telepathology was held in Heidelberg. 2 Many aspects of telepathology were presented including an introduction to telepathology, technical specifications, standardization, legal aspects and expert consultation. Telepathology was used, at that time, in Scandinavia for remote diagnosis of frozen sections 3'4 and also in France, Greece 5'6 and later in Japan 7 and the U S A s for histology and cytology. A recent literature search from 1995 to 1996 indicated that there was world-wide interest in the research, development and application of telepathology.919 In October 1996, an article in The Guardian newspaper, entitled 'Second opinions from space,' described the use of telepathology at the Norwegian Radium Hospital, a cancer treatment centre in Oslo. 2~ it was claimed that such technology could be used to boost the accuracy of cancer tests, thus relieving patients from the trauma of an incorrect diagnosis, and indeed, in January 1997, a whole edition of a major pathology journal was
C. Sowter and C. A. Wells, Department of Histopathology,St Bartholomew's Hospital, Royal Hospitals Trust, London ECIA 7BE, UK. (Requests for offprints to C. Sowter). 65
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CURRENT DIAGNOSTIC PATHOLOGY
devoted to telepathology. In the meantime, a European Union research project (EUROPATH) involving many of the member states began in 1996. It is clear that many feel that there is a role for telepathology in the field of diagnostic histopathology and cytology. SYSTEM C O M P O N E N T S Before discussing the application and use of telepathology in routine pathology, it is necessary to consider the hardware and software which together produce a telepathology system. Telepathology systems require a microscope, a television (TV) camera, an adaptor to connect it to the microscope, a computer, a high-resolution monitor, a communication device and appropriate software. Images can be incorporated into the system as macro or micro images. For remote-controlled consultation the microscope must be fully automated and computer controlled. The images are captured, digitized and displayed using TV technology. A 'receive only' system, as used by the quality assurance project, does not need a microscope or a camera. Images are transmitted and received between telepathology systems by using one of the following protocols; telephone services, networks or satellite links.
A BASIC TELEPATHOLOGY SYSTEM The component parts of any telepathology system are: (i) camera: (ii) camera adaptor; (iii) computer; and (iv) display console, telepathology software and communications.
Camera There are currently three types of TV camera in general use; analogue, digital and mixed analogue and digital. Traditionally TV cameras were analogue devices. A few years ago, digital cameras were introduced which provided very high-quality images. These cameras are slow and expensive. Last year new digital cameras were introduced. Many were hybrid devices with both analogue and digital outputs. They would appear to offer the advantages of both analogue and digital cameras for less expense then a fully digital camera. Analogue cameras
These cameras are either single chip or three chip. Single chip cameras are cheaper and usually provide poorer quality images. The colour image is obtained by using three electronic filters to obtain the red, green and blue image information needed to produce a colour image. Three chip cameras collect the red, green and blue data directly from each chip. Prices range from about s 000 to s 000. The output from these cameras needs to be digitized before it can be stored in the memory of the computer. A frame grabber is needed to digitize and capture the image. The size of a digitized image is usually
512 x 512, 640 • 480 or 768 x 512 pixels. Some frame grabbers are able to capture and display images while others are simple devices that require an additional display card. The computer monitor requires a screen resolution of 1 024 x 768 or better and be able to display at least 256 colours. It an additional graphics display card is fitted then a screen resolution of 1 280 x 1 024 and 16.7 million colours is possible. It should be noted that not all cards will work with all computers and not all cards may be supported by future versions of computer hardware and software. Digital cameras
Digital cameras can provide very high-quality images and, because their output is digital, they do not require a frame grabber. However, a specific image input board may still be needed. At present digital cameras are too slow for real-time applications and are expensive. For example, a ProgRes digital camera costs approximately s 000. Hybrid cameras
The new generation of hybrid cameras which can be switched from lower resolution analogue mode to higher resolution digital mode may provide a good compromise for routine use. Sony, Fuji and other manufacturers sell this type of camera, prices are currently believed to be s 000. Generally these cameras are too new for there to be any definite information regarding their performance or cost effectivness for telepathology. Important considerations for choosing a camera are: speed, image resolution, image quality, ease of set-up and cost.
Camera adaptor The camera must be attached to a lens for macro work or to a microscope. Important considerations are the image size relevant to the microscope field and the physical link between the camera and the lens or microscope, Some adaptors may only allow 60-70% of the microscope field to be captured by the camera. It is clear that the remote pathologist, looking at the TV screen would not have the same information, on which to base an opinion, as the pathologist using the microscope. Without a wide-field adaptor both pathologists would not be able to see the same fields unless they worked entirely from the TV monitor screens. There are adaptors available that produce a camera field which is close in size to the microscope field. With some of these, however, unacceptable levels of distortion may be seen in the image. Ultra-wide field adaptors are relatively expensive, costing up to s 000 at today's prices and should be checked for suitability for the application before purchase. All adaptors should have a focus adjustment to enable the microscope image to be co-focal with the camera image.
AN OVERVIEWOF TELEPATHOLOGY 67 There are two types of camera fitting; the 'C' mount and bayonet. The 'C' mount is a universal adaptor but there are several different types of bayonet fitting. Cameras which use 'bayonet' fittings can be more of a problem because different manufacturers use different fittings and, therefore, several adaptors may be needed if more than one camera/lens/microscope combination is to be used.
Such software is always relatively expensive because of the number of months or years of labour needed to produce it and the small market into which it has to be sold. If telepathology systems do become widely used different commercial systems will need to communicate with each other. It will be necessary for systems to exchange images of different formats and be able to support several communication protocols.
Computer
Telecommunications
The rate of development of the personal computer (PC) shows no sign of diminishing. Performance increases and price reductions occur almost on a monthly basis. PCs currently for sale offer a performance undreamed of even 5 years ago. The speed of data transmission, storage capacity and video display quality means that these computers can be taken 'off the shelf' and used for telepathology applications. For example, a Pentiumbased PC with 166 MHz or better CPU (central processing unit), 32 Mb RAM (random access memory), 4 Mb video memory and 2 Gb of disc storage will cost s 500 or less. For an additional s a small computer systems interface (SCSI) can be purchased. A SCSI hard disk is faster than a standard hard disk and the SCSI interface allows up to seven devices to be attached. SCSI can use the TWAIN software interface which allows images to be acquired from several different sources such as digital and hybrid cameras. Additional graphics cards can provide pixel resolutions of 1 280 x 1 024 with 256 colours. A card with suficient memory to display 16.7 million colours will provide the best possible image quality for a mere s
The telecommunication protocols available are: public service telephone network (PSTN), integrated services digital network (ISDN), Internet, LAN and satellite. A search of the literature indicates that ISDN is probably the most widely used protocol, although in the UK it is expensive to install and use.
Display monitor The display monitor supplied with today's PCs will support a display resolution of at least 1 024 x 768 pixels and 256 colours. Display monitors should have a screen size of at least 17". Such monitors increase the cost of a computer by about s Even better image displays can be obtained using high-resolution monitors with larger screens 20-21". These are available from manufacturers such as Sony and Mitsubishi at costs of up to s 000.
PSTN STD telephones are analogue devices and require the use of a 'modem' (modulator/demodulator). A modem is needed on both the transmitting system and the receiving system to convert digital signals to analogue signals prior to transmission and then to convert the analogue signal back to a digital signal on receipt. The speed of data transfer is measured as kilobits per second (Kbps). Last year the standard transmission speed for a modem was raised from 14.4 Kbps to 28.8 Kbps and then 33.6 Kbps by the end of the year. The next generation of modems is claimed to have a potential data transmission speed of 57.6 Kbps or even 64 Kbps. This improvement in speed coupled with image compression has renewed interest in this inexpensive form of data transmission. Image transfer of 100 Kb (800 Kbps) when connected at about 22 Kbps takes about 36 sec for high-quality transmission and 20 sec for medium-quality transmission. The next generation of modems may reduce the transmission time to approximately 15 sec and 6 sec, respectively. Modems are required only when analogue to digital (and vice versa) conversions are needed. They are not needed for digital transmissions using ISDN. 2~ ISDN
Computer software for telepathology Commercial software packages are available for telepathology. The software requirements vary immensely with different telepathology applications and many factors influence the software required for specific uses within a routine pathology environment. The basic requirements are: 9 Well-designed user interface 9 Simple set-up procedure for the communication system 9 Simple selection and set-up procedure for the camera 9 Easy image storage and retrieval 9 Easy creation and use of case documents.
There are two different ISDN services available in the UK; (i) BRI, the basic rate interface; and (ii) PR1, the primary rate interface. Generally, the BRI ISDN service can be 2 or 6 channels, each of 64 Kbps; transmission speeds, therefore, are 128 and 384 Kbps. These are known as ISDN 2, and ISDN 6. Thus ISDN 2 is twice as fast as the new PSTN modem of 64 Kbps. ISDN is used to transmit both voice and data. With ISDN 2 one channel may be used for voice and the other used for data. Such a configuration is, therefore, no better than using two standard telephone lines and image transmission times would be similar to PSTN using the next generation of modems. It is possible to upgrade from ISDN 2 to ISDN 6 which, using image
68 CURRENT DIAGNOSTIC PATHOLOGY
resolutions previously described, could provide image transmission in almost real time. A new installation is needed for PRI. The maximum speed of PRI (ISDN 30) is 2 megabits/sec. The installation cost of ISDN, however, is considerably higher than PSTN and the line rental for laboratories using this only occasionally would be totally unjustifiable. Networks
There is widespread use of networks for communication particularly the Internet. This service provides a method of communication which is extremely inexpensive even over long distances. The disadvantages of the Internet are security, access: for NHS hospitals and the variable speed of data transmission. Nevertheless, there are some telepathology applications which are suited to this protocol. Area networks. Local area networks exist in universities and hospitals. They can be very fast enabling real-time communications and the cost to individual departments is negligible. A major disadvantage is that academic networks and clinical networks may not be allowed to link with each other due to security considerations. Internet. This is a well-known example of a network. The disadvantages of it are that the speed of data transfer varies continuously and there are questions about its security. The construction of other networks, such as the London Metropolitan Area network has already started. The aim of these networks is to offer users a sustainable bandwidth able to provide individual users with highspeed data links and greater levels of security. Satellite links
Satellite links offer the highest data transmission speeds, but their very high operational costs prevent them from being in common use.
TELEPATHOLOGY SYSTEMS IN USE The system consists of a sender (laboratory) site and a Laboratory
,,,,,,
i
remote receiving site. At the remote site, a microscope is fitted with a high-quality digital camera. The digital camera has a base resolution of approximately 800 • 600 pixels and is capable of capturing 24-bit (true colour) still images. The microscope has remote control for the stage, focus, objective nosepiece, field and condenser irises, condenser and light source. Somewhat lower cost remote microscopes where only the stage and focus are motorized do exist and could be used with a person at the remote site to change objectives and load and unload slides (Fig. 1). The software running on the remote work-station interprets control signals from the laboratory workstation and controls the microscope, camera and stage. The laboratory work-station displays the captured images and provides a user-friendly way of issuing commands to the remote microscope and camera. Marking tools, annotating images and 'dual' cursors are already available. These enable the users at each site to indicate areas of interest within the specimen. This is an example of a real-time system. For such a system the communication link must be primary rate ISDN, ATM or satellite. Image transmission becomes faster when image size is reduced using a compression technique. Images can be compressed using hardware or, more commonly, software. One method of image compression, JPEG (Joint Photographic Experts Group) reduces the size of a 640 x 480 pixel image with 24 bits per pixel of colour information from about 900 Kb to 90 Kb, o r l 0 : 1. I t may be possible to have real-time communications using ISDN 6 if a standard microscope is used instead of a fully automated computer controlled system. In such circumstances instructions in the use of the microscope would be given verbally. Data transmission speeds of less than ISDN 6 cannot be used for real-time data transfer. However, they are substantially cheaper and can be used when speed is not a priority (e.g. teaching, quality assurance and accessing databases). These systems may be used when there are international time differences or for 'earliest convenience' diagnosis, when images can be sent prior to consultation. Remote Site
J
,
o~mlunication
!
i ooo I Link
Fig. 1--An example of a two-way link-up using high quality images.
AN OVERVIEWOF TELEPATHOLOGY 69
TELEPATHOLOGY APPLICATIONS The integration of multimedia telecommunication between pathologists is designed to improve quality assurance and diagnostic accuracy in routine practice. Practical objectives of telepathology are: 9 Enable expert opinions to be sought on the interpretation of the microscopic appearances of biopsy or cytology samples 9 Provide better medical education and thus improve diagnostic accuracy by providing access to international cancer databases 9 Continue postgraduate education by developing reference banks of quality assured images 9 Maximise cost efficiency by disseminating information to a wide audience within a short period. Research projects currently using telepathology are: (1) Implementation of multimedia databases for: (i) pathology case reports and jurisprudence; (ii) reference macro- and microscopic images; (iii) markers provided by cytometry, cytogenetics and biochemistry (2) Design of inter-operability standards and guidelines for: (i) remote consultation; (ii) remotely driven microscopy (3) Remote diagnosis, referrals, consensus tele-conferences, quality assurance and teaching. Continued medical education (CME) programmes are currently being developed for many specialities and one side-effect of the protocol would be that a reference bank of quality assured images would be developed. These images would be available for future teaching and CME programmes. These materials can then be accessed at will by interested pathologists. The Medline reference system is a simple example where this type of system works well. Q U A L I T Y ASSURANCE BREAST S C R E E N I N G . H I S T O P A T H O L O G Y AND C Y T O L O G Y Telepathology can be used for quality assurance (QA), thus increasing proficiency and consistency of diagnosis, particularly in the UK Breast and Cervical Screening Programmes. 22 The traditional way of doing QA in pathology is time consuming and inefficient. In practice, one round of QA in the UK Breast Screening Programme takes 6 months to complete. External quality assurance (EQA) within the Breast Screening Programme has demonstrated the problems of using the postal services to circulate sets of slides to different hospital laboratories. Queries from laboratories who have not received the slides must be investigated. Delays occur during holiday periods. In the UK people are permanently employed in each region to physically visit each cytology laboratory with cytology slides and examine the proficiency of each cytologist in situ. This is necessary because it is impossible to make duplicate slides of cytology samples and slides can often
be irretrievably broken in transit. Duplicate images of any sample can be made by telepathology hence eliminating this practical bottleneck. The microscopic appearance of a lesion may vary from section to section depending on the site of the section. For example, a small focus of cancer developing in a benign lesion may be present only on some of the sections. Under these circumstances consistency of diagnosis is impossible. Further, the introduction of 'Caiman' cancer units and 'Caiman' cancer centres has demonstrated a clear need for consistent pathological diagnosis. EQA by telepathology would enable the scheme to be extended to all Caiman cancer unit pathologists, and permit a national circulation of slides to be used as a learning tool. The need for such an EQA scheme will increase as pathologists inexperienced in this field are faced with breast cytodiagnosisY Telepathology enables interactive feedback by which QA cases can be discussed and thus increase the diagnostic accuracy of pathologists involved. It will also enable the interactive discussion of referral cases leading to more secure pathological diagnosis in difficult cases. Ultimately seeking a specialist opinion on cases of difficulty will be quicker and easier. EQA pilot study using telepathology A small telepathology project in the North Thames region to evaluate the use of telepathology for EQA in histopathology and cytopathology began in December 1996. 24 The aims of the project are to: 9 Set up a small telepathology network by selecting sites for the development of telepathology throughout the region including some of the possible Caiman cancer units 9 Use this network to test whether QA in pathology is possible by telepathology 9 Compare the results of diagnosis by telepathology with the returns to the Cancer Screening Evaluation Unit for breast diagnosis on the National EQA Scheme 9 Identify the problems of using this technology for QA. 9 Extend the system to test breast and cervical cytology EQA. The project consists of three parts: (i) setting up the network; (ii) validation of the protocols used; and (iii) evaluation of the results. The resource implications are not great. The cost of receiving stations is about s 600 per laboratory plus telephone line costs. A full telepathology system equipped to send and receive documents and images is less then s 000 plus running costs.
Setting up the network The specification of the receiving stations to be set up in pathology laboratories has been determined. These systems comprise PCs running at 133 MHz or 166 MHz,
70 CURRENTDIAGNOSTIC PATHOLOGY an enhanced display adaptor board, an external modem and telepathology software. These systems do not require cameras and frame grabbers although they could be fitted at a later date to upgrade the system to a full telepathology specification. Six remote installations were used. On-site installation of the system and training in its use took 1 day. Image transmissions were made to all receiving stations to re-establish familiarity with the use of the system and validate the recording of data. The five remote sites were contacted in turn and six test cases were transmitted. One remote site was unable to establish a good telephone link which increased the transmission time for one case. Nevertheless, 29/30 case documents were transmitted; good telephone connections taking between 15 and 30 min/case. The cases can also be accessed from the Internet. These cases are available for assessment by all interested pathologists with Internet access. Facilities exist for returning opinions anonymously. A typical screen display of the same case is illustrated viewed from the telepathology system (Fig. 2) and the Internet (Fig. 3). Test cases for the quality assurance trials were taken from slides used in the National Breast Screening Quality Assurance = scheme and representative images from these slides were digitized by the Regional Breast Screening Pathology Co-ordinator. Images showing the
Fig. 2--A typical display from the SAMBA telepathology system.
Fig. 3 - - A typical Internet display from the quality assurance programme.
diagnostic features in the view of the co-ordinator were interspersed with other images from the same case which were not definitively diagnostic. Approximately 15-17 images were taken for each case including one of the whole slide area; 10 high-power views of different areas were included for all cases as they were needed for grading on the cancers. Not to include them for the benign cases would have biased the opinion of the remote pathologist. The initial reactions to the images by the participating pathologists in the study was generally favourable with comments such as 'The pictures on high power are very clear and of high quality' and 'I do not think it will be impossible for the diagnostic pathologist to make a judgement on any of these cases'. Some comments reflected problems in the system at present such as 'There is no need to send 10 high-power images on a benign case', 'There is no way to make a size estimation of the tumour' and 'The low power is not so clear but that is comparable to p i c t u r e s . . , taken under the ordinary microscope'. All of these criticisms were all relatively minor and are being addressed. The objective results are still under analysis. DISCUSSION Some pathologists have expressed doubts about the use of telepathology and have questioned whether the need exists. Others have doubted if computer monitors can be used for making a diagnosis, although results have demonstrated no significant difference between pathologist performance using a microscope compared with a video imageY Moreover, such systems are not accepted as being affordable or cost effective by many working in routine pathology. Many pathologists believe, however, that fast access to expert opinion is the key to reducing the numbers of diagnostic errors. In the European Union about 200 million histological and cytological preparations a year are examined by highly dedicated specialists in 3 000 laboratories for a cost of 2 000 million ECUs. A less well-known European statistic suggesting that up to 5% of cancer diagnoses could be wrong was cited in a report in The Guardian, October 1996, which also claimed that Europe will have about 1 million errors in cancer diagnosis. Although most of these are not necessarily critical to the patient, some could be. 2~ In spite of the objections to telepathology, the numerous initiatives making use of telematics in pathology indicate the potential of this technology. Of the problems which remain to be solved when using telepathology, few are technological. The high purchase cost of a fully automated remote diagnosis system, high running costs and potentially infrequent use are the major obstacles to using telepathology. There are still problems in the application and use of this technology which require further research and development; for example, the user interface, image selection and its effect upon diagnosis, and the legal implications.
AN OVERVIEW OF TELEPATHOLOGY
At present telepathology systems for cancer diagnosis appear to be directed at remote frozen-section diagnosis using low-resolution images. This may not be the appropriate application, however, since frozen sections make up only a small percentage of laboratory cases and the rate is falling. Nevertheless, there are several fields where telepathology can provide a useful service. For example, databases for case reports, reference images and tumour markers may be useful for diagnostic pathology. Telepathology could provide a means of combining referral and CME. It is accepted that still there are many unknown factors which may reduce the usefulness of telepathology; for example: 9 the number of images to be sent for all applications? 9 the type of image (resolution, magnification, field area)? 9 under remote control, which microscope functions need to be directly controlled? 9 what are acceptable methods to assess quality assurance/training? 9 what is needed to form an adequate portfolio of images for diagnosis? 9 what are the priorities, likely demands and acceptable costs? THE W A Y F O R W A R D Many of the concerns expressed about the use of telepathology are not derived from knowledge. There is a need to involve as many pathologists as possible in the use of these systems, particularly pathologists working in routine service roles. Such a wide user base would enable speedier dissemination of information. Pathologists seeking expert opinion would be able to derive the same benefits from a consultation as those using nmltiheaded microscopes. There are few technological problems remaining; a lack of funding is the major problem to the implementation of telepathology. It is difficult or impossible for many laboratories to consider the use of telematics due to cost. This situation seems unlikely to change in the UK. High costs combined with the relatively infrequent use of telepathology systems has renewed the interest in the use of the public service telephone network. Recent improvements in the performance of modems could result in a potential four times increase in data transmission speed. For many applications of telepathology this may be considered a cost-effective solution although it is still very slow in comparison with even the basic rate interface for ISDN. Therefore, there is a pressing need to develop telepathology systems at the lower end of the market which utilize cheap communications such as standard telephone lines. Such systems can form the basis for: (1) Quality assurance schemes which offer the advantages of: (i) no specimen/slide loss; (ii) almost simultaneous circulation of QA cases; (iii) consistency of diagnostic features on every image sent to each laboratory
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(2) Referral schemes (3) Remote diagnosis (4) Teaching. There is still a need to improve the speed of data transmission without significant increase in cost. This may result from improved image compression techniques. It is claimed that Fairfield Telepathology, UK, compression software which can reduce the digital image size by about 50 times without eroding the picture quality. Research is still needed to determine the usability and the accuracy of diagnosis using a dynamic digital telepathology system.
ACKNOWLEDGEMENTS The Quality Assurance project described is funded by a grant from the North Thames Breast Screening Quality Assurance Unit (QA Manager Dr N. Perry). The European Pathology Assisted by Telematics for Health (EUROPATH project No HC-1038 of DGXIII) is supported by the European Union (Project Co-ordinator Professor G. Brugal, Grenoble).
REFERENCES 1. Weinstein R S. Telepathology comes of age in Norway. Hum Pathol 1991; 22: 511-513. 2. Proceedings ofthe 1st European Symposium on Telepathology. Zentralbl Pathol 1992; 138. 3. Nordrum I, Engum B, Eivind R, et al. Remote section service: a telepathology project in northern Norway. Hum Pathol 1992; 22: 514-518. 4. Tor J E, Nordrum 1. Frozen section service via the telenetwork in northern Norway Zentralbl Pathnl 1992; 138: 405~407. 5. Martin E, Dusserre P, Fages A, Hauri P, Viellefond A, Bastien H. Telepathology: A new tool of pathology? Presentation of a French national network. Zentralbl Pathol 1992; 138:419423. 6. Miaoulis G, Protopappa E, Skourlas C, Deldis G. Telepathology in Greece. Experience of the Metaxas Cancer Institute. Zentralbl Pathol 1992; 138: 425~428. 7. lto H, Adachi H, Taniyama F, Fukada Y, Dohi K. Telepathology is available for transplantation pathology: experience in Japan using an integrated low cost and high quality system. Mod Pathol 1994; 7: 80t-805. 8. Weinstein R S, Bhattacharyya A, Yu Y P e t al. Pathology consultation services via the Arizona: International Telemedicine network. Archives de Anatomie et de Cytologie Pathologiques 1995; 43:219 226. 9. Martin E D, Dusserre P, Flandrin G, Got C, Vieillefond A, Vacher-Lavenu M C. Contribution of computers and telepathology in cancerologic pathology. Bulletin du Cancer 1995; 82: $565-568. 10. Weinberg D S. How is telepathology being used to improve patient care? Clinical Chemistry 1996; 42:831 835. 11. Raab S S, Zaleski M S, Thomas P A, Niemann T H, Isacson C, Jensen C S. Telecytology: diagnostic accuracy in cervical-vaginal smears. Am J Clin Pathol 1996; 105: 599-603. 12. Weinberg D S, Allaert F A, Dusserre P e t al. Telepathology diagnosis by means of digital still images: an international validation study. Hum Pathol. 1996; 27:11-18. 13. Alleart F A, Weinberg D, Dussetre P, Yvon P J, Dusserre L, Cotran P. Evaluation of a telepathology system between Boston (USA) and Dijon (France): glass slides versus telediagnostic TV monitor. Proceedings of the Annual Symposium on Computer Applications in Medical Care 1995; 596-600. 14. Fujita M, Suzuki Y, Takahashi M, Tsukamoto K, Nagashima K. The validity of intraoperative frozen section diagnosis based on video-microscopy (telepathology). Gen Diag Pathol 1995; 141: 105-110. 15. Richter H A, Danaei M, Maurin N, Minermayer C. Multimedic system for telepathology and interdisciplinary councils between doctors and various hospitals. Archives d' Anatomie et de Cytologie Pathologiques 1995; 43: 296-299. 16. Goncalves L, Cunha C. Telemedicine project in the Azores
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Islands. Archives d' Anatomie et de Cytologie Pathotogiques 1995; 43: 285-287. Danilovic Z, Dzubur A, Seiwerth S. Concept of telepathology in Croatia. Archives d' Anatomie et de Cytologie Pathologiques 1995; 43: 282-284. Boeryd B R. Experience with distant pathology demonstrations for clinicians in hospitals without local pathologists through the Swedish telepathology work station. Archives d' Anatomie et de Cytologie Pathologiques 1995; 43: 266-267. Busch C, Olsson S. Future strategy for telepathology in Sweden: higher resolution, real-time transmission in a multipurpose work station for diagnostic pathology. Archives d' Anatome et de Cytologie Pathologiques 1995; 43: 242-245. Marks P. Second opinions from space. The Guardian, 16 October, 1996.
21. British Telecommunications Information. ISDN many applications: a single tool. British Telecommunications 1993. 22. UK National Coordinating Group for breast screening pathology. Consistency of histological reporting of breast lesions detected by screening: Findings of the UK National External Quality Assessment (EQA) Scheme. Eur J Cancer 1994; 30: 1414-1419. 23. Wells C A. Quality assurance in breast cancer screening cytology: A review of the literature and a report on the UK national cytology scheme. Eur J Cancer 1995; 31: 273-280. 24. Sowter C, Domizio P, Wells C A, Lowe D G. Quality Assurance using telepathology and standard telecommunications: a viable alternative to the post office? J Pathol 1997; 181(Suppl.): 27. 25. Swets J A, Pickett R M, Whitehead S E et al. Assessment of diagnostic technologies. Science 1979; 205: 753-759.
9 1997 Pearson Professional Ltd
Mini-symposium: Telepathology
System requirements, the use of telepathology in diagnostic pathology and its application to quality assurance programmes
C. S o w t e r and C. A. W e l l s
INTRODUCTION
system is dependent on its application, the basic system can be considered as four component groups: hardware, software, the user interface, and the user. This review will explain, in general terms, the setup, implementation and the application of telepathology systems to pathology. Only the use of telepathology for breast quality assurance will be discussed in detail.
The concept of using video microscopy to provide diagnostic services to remote locations was first described in the USA in 1968, when monochrome images were transmitted in real time. The communication protocol was a dedicated point-to-point microwave link. Eighteen years later, in 1986, a prototype commercial system using colour images, computer controlled microscopy, highdefinition television and satellite communication was described. It was not, however, until 1990 that a commercial telepathology system became available. I Since 1990, the development of telepathology has led to its routine use in some countries. There are no technological problems to be solved. The high-speed communication costs needed for remote diagnosis and remote consultation are, however, very expensive. These costs are a major obstacle to the routine application of telepathology within the UK. The multimedia computers now available at very low prices can be used as the basis of telepathology systems. Such systems can be used for remote consultation of experts or consensus diagnosis using microscope teleconferencing. Both require real-time performance. Other applications such as quality assurance, continuing medical education (CME) and teaching do not need a realtime capability and the lower purchase and running costs of such telepathology systems should make them cost effective. Telepathology should help to streamline quality assurance and improve diagnostic accuracy. Although the exact specification of a telepathology
I N T E R N A T I O N A L I N T E R E S T IN TELEPATHOLOGY Some pathologists believe that telepathology is too expensive and that it does not have a useful role in routine pathology. However, there has been increasing interest in its use throughout the world. In 1992, the 1st European Symposium on Telepathology was held in Heidelberg. 2 Many aspects of telepathology were presented including an introduction to telepathology, technical specifications, standardization, legal aspects and expert consultation. Telepathology was used, at that time, in Scandinavia for remote diagnosis of frozen sections 3'4 and also in France, Greece 5'6 and later in Japan 7 and the U S A s for histology and cytology. A recent literature search from 1995 to 1996 indicated that there was world-wide interest in the research, development and application of telepathology.919 In October 1996, an article in The Guardian newspaper, entitled 'Second opinions from space,' described the use of telepathology at the Norwegian Radium Hospital, a cancer treatment centre in Oslo. 2~ it was claimed that such technology could be used to boost the accuracy of cancer tests, thus relieving patients from the trauma of an incorrect diagnosis, and indeed, in January 1997, a whole edition of a major pathology journal was
C. Sowter and C. A. Wells, Department of Histopathology,St Bartholomew's Hospital, Royal Hospitals Trust, London ECIA 7BE, UK. (Requests for offprints to C. Sowter). 65
66
CURRENT DIAGNOSTIC PATHOLOGY
devoted to telepathology. In the meantime, a European Union research project (EUROPATH) involving many of the member states began in 1996. It is clear that many feel that there is a role for telepathology in the field of diagnostic histopathology and cytology. SYSTEM C O M P O N E N T S Before discussing the application and use of telepathology in routine pathology, it is necessary to consider the hardware and software which together produce a telepathology system. Telepathology systems require a microscope, a television (TV) camera, an adaptor to connect it to the microscope, a computer, a high-resolution monitor, a communication device and appropriate software. Images can be incorporated into the system as macro or micro images. For remote-controlled consultation the microscope must be fully automated and computer controlled. The images are captured, digitized and displayed using TV technology. A 'receive only' system, as used by the quality assurance project, does not need a microscope or a camera. Images are transmitted and received between telepathology systems by using one of the following protocols; telephone services, networks or satellite links.
A BASIC TELEPATHOLOGY SYSTEM The component parts of any telepathology system are: (i) camera: (ii) camera adaptor; (iii) computer; and (iv) display console, telepathology software and communications.
Camera There are currently three types of TV camera in general use; analogue, digital and mixed analogue and digital. Traditionally TV cameras were analogue devices. A few years ago, digital cameras were introduced which provided very high-quality images. These cameras are slow and expensive. Last year new digital cameras were introduced. Many were hybrid devices with both analogue and digital outputs. They would appear to offer the advantages of both analogue and digital cameras for less expense then a fully digital camera. Analogue cameras
These cameras are either single chip or three chip. Single chip cameras are cheaper and usually provide poorer quality images. The colour image is obtained by using three electronic filters to obtain the red, green and blue image information needed to produce a colour image. Three chip cameras collect the red, green and blue data directly from each chip. Prices range from about s 000 to s 000. The output from these cameras needs to be digitized before it can be stored in the memory of the computer. A frame grabber is needed to digitize and capture the image. The size of a digitized image is usually
512 x 512, 640 • 480 or 768 x 512 pixels. Some frame grabbers are able to capture and display images while others are simple devices that require an additional display card. The computer monitor requires a screen resolution of 1 024 x 768 or better and be able to display at least 256 colours. It an additional graphics display card is fitted then a screen resolution of 1 280 x 1 024 and 16.7 million colours is possible. It should be noted that not all cards will work with all computers and not all cards may be supported by future versions of computer hardware and software. Digital cameras
Digital cameras can provide very high-quality images and, because their output is digital, they do not require a frame grabber. However, a specific image input board may still be needed. At present digital cameras are too slow for real-time applications and are expensive. For example, a ProgRes digital camera costs approximately s 000. Hybrid cameras
The new generation of hybrid cameras which can be switched from lower resolution analogue mode to higher resolution digital mode may provide a good compromise for routine use. Sony, Fuji and other manufacturers sell this type of camera, prices are currently believed to be s 000. Generally these cameras are too new for there to be any definite information regarding their performance or cost effectivness for telepathology. Important considerations for choosing a camera are: speed, image resolution, image quality, ease of set-up and cost.
Camera adaptor The camera must be attached to a lens for macro work or to a microscope. Important considerations are the image size relevant to the microscope field and the physical link between the camera and the lens or microscope, Some adaptors may only allow 60-70% of the microscope field to be captured by the camera. It is clear that the remote pathologist, looking at the TV screen would not have the same information, on which to base an opinion, as the pathologist using the microscope. Without a wide-field adaptor both pathologists would not be able to see the same fields unless they worked entirely from the TV monitor screens. There are adaptors available that produce a camera field which is close in size to the microscope field. With some of these, however, unacceptable levels of distortion may be seen in the image. Ultra-wide field adaptors are relatively expensive, costing up to s 000 at today's prices and should be checked for suitability for the application before purchase. All adaptors should have a focus adjustment to enable the microscope image to be co-focal with the camera image.
AN OVERVIEWOF TELEPATHOLOGY 67 There are two types of camera fitting; the 'C' mount and bayonet. The 'C' mount is a universal adaptor but there are several different types of bayonet fitting. Cameras which use 'bayonet' fittings can be more of a problem because different manufacturers use different fittings and, therefore, several adaptors may be needed if more than one camera/lens/microscope combination is to be used.
Such software is always relatively expensive because of the number of months or years of labour needed to produce it and the small market into which it has to be sold. If telepathology systems do become widely used different commercial systems will need to communicate with each other. It will be necessary for systems to exchange images of different formats and be able to support several communication protocols.
Computer
Telecommunications
The rate of development of the personal computer (PC) shows no sign of diminishing. Performance increases and price reductions occur almost on a monthly basis. PCs currently for sale offer a performance undreamed of even 5 years ago. The speed of data transmission, storage capacity and video display quality means that these computers can be taken 'off the shelf' and used for telepathology applications. For example, a Pentiumbased PC with 166 MHz or better CPU (central processing unit), 32 Mb RAM (random access memory), 4 Mb video memory and 2 Gb of disc storage will cost s 500 or less. For an additional s a small computer systems interface (SCSI) can be purchased. A SCSI hard disk is faster than a standard hard disk and the SCSI interface allows up to seven devices to be attached. SCSI can use the TWAIN software interface which allows images to be acquired from several different sources such as digital and hybrid cameras. Additional graphics cards can provide pixel resolutions of 1 280 x 1 024 with 256 colours. A card with suficient memory to display 16.7 million colours will provide the best possible image quality for a mere s
The telecommunication protocols available are: public service telephone network (PSTN), integrated services digital network (ISDN), Internet, LAN and satellite. A search of the literature indicates that ISDN is probably the most widely used protocol, although in the UK it is expensive to install and use.
Display monitor The display monitor supplied with today's PCs will support a display resolution of at least 1 024 x 768 pixels and 256 colours. Display monitors should have a screen size of at least 17". Such monitors increase the cost of a computer by about s Even better image displays can be obtained using high-resolution monitors with larger screens 20-21". These are available from manufacturers such as Sony and Mitsubishi at costs of up to s 000.
PSTN STD telephones are analogue devices and require the use of a 'modem' (modulator/demodulator). A modem is needed on both the transmitting system and the receiving system to convert digital signals to analogue signals prior to transmission and then to convert the analogue signal back to a digital signal on receipt. The speed of data transfer is measured as kilobits per second (Kbps). Last year the standard transmission speed for a modem was raised from 14.4 Kbps to 28.8 Kbps and then 33.6 Kbps by the end of the year. The next generation of modems is claimed to have a potential data transmission speed of 57.6 Kbps or even 64 Kbps. This improvement in speed coupled with image compression has renewed interest in this inexpensive form of data transmission. Image transfer of 100 Kb (800 Kbps) when connected at about 22 Kbps takes about 36 sec for high-quality transmission and 20 sec for medium-quality transmission. The next generation of modems may reduce the transmission time to approximately 15 sec and 6 sec, respectively. Modems are required only when analogue to digital (and vice versa) conversions are needed. They are not needed for digital transmissions using ISDN. 2~ ISDN
Computer software for telepathology Commercial software packages are available for telepathology. The software requirements vary immensely with different telepathology applications and many factors influence the software required for specific uses within a routine pathology environment. The basic requirements are: 9 Well-designed user interface 9 Simple set-up procedure for the communication system 9 Simple selection and set-up procedure for the camera 9 Easy image storage and retrieval 9 Easy creation and use of case documents.
There are two different ISDN services available in the UK; (i) BRI, the basic rate interface; and (ii) PR1, the primary rate interface. Generally, the BRI ISDN service can be 2 or 6 channels, each of 64 Kbps; transmission speeds, therefore, are 128 and 384 Kbps. These are known as ISDN 2, and ISDN 6. Thus ISDN 2 is twice as fast as the new PSTN modem of 64 Kbps. ISDN is used to transmit both voice and data. With ISDN 2 one channel may be used for voice and the other used for data. Such a configuration is, therefore, no better than using two standard telephone lines and image transmission times would be similar to PSTN using the next generation of modems. It is possible to upgrade from ISDN 2 to ISDN 6 which, using image
68 CURRENT DIAGNOSTIC PATHOLOGY
resolutions previously described, could provide image transmission in almost real time. A new installation is needed for PRI. The maximum speed of PRI (ISDN 30) is 2 megabits/sec. The installation cost of ISDN, however, is considerably higher than PSTN and the line rental for laboratories using this only occasionally would be totally unjustifiable. Networks
There is widespread use of networks for communication particularly the Internet. This service provides a method of communication which is extremely inexpensive even over long distances. The disadvantages of the Internet are security, access: for NHS hospitals and the variable speed of data transmission. Nevertheless, there are some telepathology applications which are suited to this protocol. Area networks. Local area networks exist in universities and hospitals. They can be very fast enabling real-time communications and the cost to individual departments is negligible. A major disadvantage is that academic networks and clinical networks may not be allowed to link with each other due to security considerations. Internet. This is a well-known example of a network. The disadvantages of it are that the speed of data transfer varies continuously and there are questions about its security. The construction of other networks, such as the London Metropolitan Area network has already started. The aim of these networks is to offer users a sustainable bandwidth able to provide individual users with highspeed data links and greater levels of security. Satellite links
Satellite links offer the highest data transmission speeds, but their very high operational costs prevent them from being in common use.
TELEPATHOLOGY SYSTEMS IN USE The system consists of a sender (laboratory) site and a Laboratory
,,,,,,
i
remote receiving site. At the remote site, a microscope is fitted with a high-quality digital camera. The digital camera has a base resolution of approximately 800 • 600 pixels and is capable of capturing 24-bit (true colour) still images. The microscope has remote control for the stage, focus, objective nosepiece, field and condenser irises, condenser and light source. Somewhat lower cost remote microscopes where only the stage and focus are motorized do exist and could be used with a person at the remote site to change objectives and load and unload slides (Fig. 1). The software running on the remote work-station interprets control signals from the laboratory workstation and controls the microscope, camera and stage. The laboratory work-station displays the captured images and provides a user-friendly way of issuing commands to the remote microscope and camera. Marking tools, annotating images and 'dual' cursors are already available. These enable the users at each site to indicate areas of interest within the specimen. This is an example of a real-time system. For such a system the communication link must be primary rate ISDN, ATM or satellite. Image transmission becomes faster when image size is reduced using a compression technique. Images can be compressed using hardware or, more commonly, software. One method of image compression, JPEG (Joint Photographic Experts Group) reduces the size of a 640 x 480 pixel image with 24 bits per pixel of colour information from about 900 Kb to 90 Kb, o r l 0 : 1. I t may be possible to have real-time communications using ISDN 6 if a standard microscope is used instead of a fully automated computer controlled system. In such circumstances instructions in the use of the microscope would be given verbally. Data transmission speeds of less than ISDN 6 cannot be used for real-time data transfer. However, they are substantially cheaper and can be used when speed is not a priority (e.g. teaching, quality assurance and accessing databases). These systems may be used when there are international time differences or for 'earliest convenience' diagnosis, when images can be sent prior to consultation. Remote Site
J
,
o~mlunication
!
i ooo I Link
Fig. 1--An example of a two-way link-up using high quality images.
AN OVERVIEWOF TELEPATHOLOGY 69
TELEPATHOLOGY APPLICATIONS The integration of multimedia telecommunication between pathologists is designed to improve quality assurance and diagnostic accuracy in routine practice. Practical objectives of telepathology are: 9 Enable expert opinions to be sought on the interpretation of the microscopic appearances of biopsy or cytology samples 9 Provide better medical education and thus improve diagnostic accuracy by providing access to international cancer databases 9 Continue postgraduate education by developing reference banks of quality assured images 9 Maximise cost efficiency by disseminating information to a wide audience within a short period. Research projects currently using telepathology are: (1) Implementation of multimedia databases for: (i) pathology case reports and jurisprudence; (ii) reference macro- and microscopic images; (iii) markers provided by cytometry, cytogenetics and biochemistry (2) Design of inter-operability standards and guidelines for: (i) remote consultation; (ii) remotely driven microscopy (3) Remote diagnosis, referrals, consensus tele-conferences, quality assurance and teaching. Continued medical education (CME) programmes are currently being developed for many specialities and one side-effect of the protocol would be that a reference bank of quality assured images would be developed. These images would be available for future teaching and CME programmes. These materials can then be accessed at will by interested pathologists. The Medline reference system is a simple example where this type of system works well. Q U A L I T Y ASSURANCE BREAST S C R E E N I N G . H I S T O P A T H O L O G Y AND C Y T O L O G Y Telepathology can be used for quality assurance (QA), thus increasing proficiency and consistency of diagnosis, particularly in the UK Breast and Cervical Screening Programmes. 22 The traditional way of doing QA in pathology is time consuming and inefficient. In practice, one round of QA in the UK Breast Screening Programme takes 6 months to complete. External quality assurance (EQA) within the Breast Screening Programme has demonstrated the problems of using the postal services to circulate sets of slides to different hospital laboratories. Queries from laboratories who have not received the slides must be investigated. Delays occur during holiday periods. In the UK people are permanently employed in each region to physically visit each cytology laboratory with cytology slides and examine the proficiency of each cytologist in situ. This is necessary because it is impossible to make duplicate slides of cytology samples and slides can often
be irretrievably broken in transit. Duplicate images of any sample can be made by telepathology hence eliminating this practical bottleneck. The microscopic appearance of a lesion may vary from section to section depending on the site of the section. For example, a small focus of cancer developing in a benign lesion may be present only on some of the sections. Under these circumstances consistency of diagnosis is impossible. Further, the introduction of 'Caiman' cancer units and 'Caiman' cancer centres has demonstrated a clear need for consistent pathological diagnosis. EQA by telepathology would enable the scheme to be extended to all Caiman cancer unit pathologists, and permit a national circulation of slides to be used as a learning tool. The need for such an EQA scheme will increase as pathologists inexperienced in this field are faced with breast cytodiagnosisY Telepathology enables interactive feedback by which QA cases can be discussed and thus increase the diagnostic accuracy of pathologists involved. It will also enable the interactive discussion of referral cases leading to more secure pathological diagnosis in difficult cases. Ultimately seeking a specialist opinion on cases of difficulty will be quicker and easier. EQA pilot study using telepathology A small telepathology project in the North Thames region to evaluate the use of telepathology for EQA in histopathology and cytopathology began in December 1996. 24 The aims of the project are to: 9 Set up a small telepathology network by selecting sites for the development of telepathology throughout the region including some of the possible Caiman cancer units 9 Use this network to test whether QA in pathology is possible by telepathology 9 Compare the results of diagnosis by telepathology with the returns to the Cancer Screening Evaluation Unit for breast diagnosis on the National EQA Scheme 9 Identify the problems of using this technology for QA. 9 Extend the system to test breast and cervical cytology EQA. The project consists of three parts: (i) setting up the network; (ii) validation of the protocols used; and (iii) evaluation of the results. The resource implications are not great. The cost of receiving stations is about s 600 per laboratory plus telephone line costs. A full telepathology system equipped to send and receive documents and images is less then s 000 plus running costs.
Setting up the network The specification of the receiving stations to be set up in pathology laboratories has been determined. These systems comprise PCs running at 133 MHz or 166 MHz,
70 CURRENTDIAGNOSTIC PATHOLOGY an enhanced display adaptor board, an external modem and telepathology software. These systems do not require cameras and frame grabbers although they could be fitted at a later date to upgrade the system to a full telepathology specification. Six remote installations were used. On-site installation of the system and training in its use took 1 day. Image transmissions were made to all receiving stations to re-establish familiarity with the use of the system and validate the recording of data. The five remote sites were contacted in turn and six test cases were transmitted. One remote site was unable to establish a good telephone link which increased the transmission time for one case. Nevertheless, 29/30 case documents were transmitted; good telephone connections taking between 15 and 30 min/case. The cases can also be accessed from the Internet. These cases are available for assessment by all interested pathologists with Internet access. Facilities exist for returning opinions anonymously. A typical screen display of the same case is illustrated viewed from the telepathology system (Fig. 2) and the Internet (Fig. 3). Test cases for the quality assurance trials were taken from slides used in the National Breast Screening Quality Assurance = scheme and representative images from these slides were digitized by the Regional Breast Screening Pathology Co-ordinator. Images showing the
Fig. 2--A typical display from the SAMBA telepathology system.
Fig. 3 - - A typical Internet display from the quality assurance programme.
diagnostic features in the view of the co-ordinator were interspersed with other images from the same case which were not definitively diagnostic. Approximately 15-17 images were taken for each case including one of the whole slide area; 10 high-power views of different areas were included for all cases as they were needed for grading on the cancers. Not to include them for the benign cases would have biased the opinion of the remote pathologist. The initial reactions to the images by the participating pathologists in the study was generally favourable with comments such as 'The pictures on high power are very clear and of high quality' and 'I do not think it will be impossible for the diagnostic pathologist to make a judgement on any of these cases'. Some comments reflected problems in the system at present such as 'There is no need to send 10 high-power images on a benign case', 'There is no way to make a size estimation of the tumour' and 'The low power is not so clear but that is comparable to p i c t u r e s . . , taken under the ordinary microscope'. All of these criticisms were all relatively minor and are being addressed. The objective results are still under analysis. DISCUSSION Some pathologists have expressed doubts about the use of telepathology and have questioned whether the need exists. Others have doubted if computer monitors can be used for making a diagnosis, although results have demonstrated no significant difference between pathologist performance using a microscope compared with a video imageY Moreover, such systems are not accepted as being affordable or cost effective by many working in routine pathology. Many pathologists believe, however, that fast access to expert opinion is the key to reducing the numbers of diagnostic errors. In the European Union about 200 million histological and cytological preparations a year are examined by highly dedicated specialists in 3 000 laboratories for a cost of 2 000 million ECUs. A less well-known European statistic suggesting that up to 5% of cancer diagnoses could be wrong was cited in a report in The Guardian, October 1996, which also claimed that Europe will have about 1 million errors in cancer diagnosis. Although most of these are not necessarily critical to the patient, some could be. 2~ In spite of the objections to telepathology, the numerous initiatives making use of telematics in pathology indicate the potential of this technology. Of the problems which remain to be solved when using telepathology, few are technological. The high purchase cost of a fully automated remote diagnosis system, high running costs and potentially infrequent use are the major obstacles to using telepathology. There are still problems in the application and use of this technology which require further research and development; for example, the user interface, image selection and its effect upon diagnosis, and the legal implications.
AN OVERVIEW OF TELEPATHOLOGY
At present telepathology systems for cancer diagnosis appear to be directed at remote frozen-section diagnosis using low-resolution images. This may not be the appropriate application, however, since frozen sections make up only a small percentage of laboratory cases and the rate is falling. Nevertheless, there are several fields where telepathology can provide a useful service. For example, databases for case reports, reference images and tumour markers may be useful for diagnostic pathology. Telepathology could provide a means of combining referral and CME. It is accepted that still there are many unknown factors which may reduce the usefulness of telepathology; for example: 9 the number of images to be sent for all applications? 9 the type of image (resolution, magnification, field area)? 9 under remote control, which microscope functions need to be directly controlled? 9 what are acceptable methods to assess quality assurance/training? 9 what is needed to form an adequate portfolio of images for diagnosis? 9 what are the priorities, likely demands and acceptable costs? THE W A Y F O R W A R D Many of the concerns expressed about the use of telepathology are not derived from knowledge. There is a need to involve as many pathologists as possible in the use of these systems, particularly pathologists working in routine service roles. Such a wide user base would enable speedier dissemination of information. Pathologists seeking expert opinion would be able to derive the same benefits from a consultation as those using nmltiheaded microscopes. There are few technological problems remaining; a lack of funding is the major problem to the implementation of telepathology. It is difficult or impossible for many laboratories to consider the use of telematics due to cost. This situation seems unlikely to change in the UK. High costs combined with the relatively infrequent use of telepathology systems has renewed the interest in the use of the public service telephone network. Recent improvements in the performance of modems could result in a potential four times increase in data transmission speed. For many applications of telepathology this may be considered a cost-effective solution although it is still very slow in comparison with even the basic rate interface for ISDN. Therefore, there is a pressing need to develop telepathology systems at the lower end of the market which utilize cheap communications such as standard telephone lines. Such systems can form the basis for: (1) Quality assurance schemes which offer the advantages of: (i) no specimen/slide loss; (ii) almost simultaneous circulation of QA cases; (iii) consistency of diagnostic features on every image sent to each laboratory
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(2) Referral schemes (3) Remote diagnosis (4) Teaching. There is still a need to improve the speed of data transmission without significant increase in cost. This may result from improved image compression techniques. It is claimed that Fairfield Telepathology, UK, compression software which can reduce the digital image size by about 50 times without eroding the picture quality. Research is still needed to determine the usability and the accuracy of diagnosis using a dynamic digital telepathology system.
ACKNOWLEDGEMENTS The Quality Assurance project described is funded by a grant from the North Thames Breast Screening Quality Assurance Unit (QA Manager Dr N. Perry). The European Pathology Assisted by Telematics for Health (EUROPATH project No HC-1038 of DGXIII) is supported by the European Union (Project Co-ordinator Professor G. Brugal, Grenoble).
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Islands. Archives d' Anatomie et de Cytologie Pathotogiques 1995; 43: 285-287. Danilovic Z, Dzubur A, Seiwerth S. Concept of telepathology in Croatia. Archives d' Anatomie et de Cytologie Pathologiques 1995; 43: 282-284. Boeryd B R. Experience with distant pathology demonstrations for clinicians in hospitals without local pathologists through the Swedish telepathology work station. Archives d' Anatomie et de Cytologie Pathologiques 1995; 43: 266-267. Busch C, Olsson S. Future strategy for telepathology in Sweden: higher resolution, real-time transmission in a multipurpose work station for diagnostic pathology. Archives d' Anatome et de Cytologie Pathologiques 1995; 43: 242-245. Marks P. Second opinions from space. The Guardian, 16 October, 1996.
21. British Telecommunications Information. ISDN many applications: a single tool. British Telecommunications 1993. 22. UK National Coordinating Group for breast screening pathology. Consistency of histological reporting of breast lesions detected by screening: Findings of the UK National External Quality Assessment (EQA) Scheme. Eur J Cancer 1994; 30: 1414-1419. 23. Wells C A. Quality assurance in breast cancer screening cytology: A review of the literature and a report on the UK national cytology scheme. Eur J Cancer 1995; 31: 273-280. 24. Sowter C, Domizio P, Wells C A, Lowe D G. Quality Assurance using telepathology and standard telecommunications: a viable alternative to the post office? J Pathol 1997; 181(Suppl.): 27. 25. Swets J A, Pickett R M, Whitehead S E et al. Assessment of diagnostic technologies. Science 1979; 205: 753-759.