TELEPATHOLOGY

Is the practice of pathology at a distance. It is the acquisition of histological, cytological and macroscopic images for transmission along telecommunication pathways for diagnosis, consultation or continuing medical education.1 It involves essentially, viewing images on a video monitor and rendering a diagnosis.

APPLICATIONS OF TELEPATHOLOGY

It is especially useful for a solo pathologist practicing in a remote area, who requires an immediate second opinion, for a case where subsequent management decisions would be based on his report. It can be especially useful in for frozen section consultations1. In addition, it can be used as a tool for quality assurance, teleconferencing and continuing medical education programmes2. Higher centres, which find it difficult to attend to increasingly larger numbers of patients, can use this as a tool to render their services more patients.

TELEPATHOLOGY SYSTEMS

A telepathology system is comprised by:

DYNAMIC TELEPATHOLOGY (Real Time Telepathology)^1,4,5

Is a telecommunication procedure for viewing live images or a sequence of images at real time. It includes remote operation of a microscope and examination of slides from a distance. The system has three requirements:

Advantages

Limitations

The major limitations are the cost and the necessity of a high bandwidth, to the tune of 1.54 Mb/s for transmission.

STORE AND FORWARD TELEPATHOLOGY (static telepathology)⁴

Is the practice of pathology at a distance, based on transmission through telecommunication means of still or stationary images from pathology specimens for their corresponding interpretation and diagnosis. It requires necessarily that the referring person is a competent professional pathologist with basic knowledge in pathology informatics. At the receiving centre also there is a pathologist who receives the electronic images and performs the interpretation and diagnosis.

Advantages

Limitations^1,4

Accuracy of Diagnosis ^1,6,7

Accuracy rates of 77% to 99% have been reported by various authors. The studies however, are not comparable, because different methodologies have been employed and the number of participating pathologists in each study is also variable. However, notably, the Arizona International Telemedicine Network has reported a concordance (between the Telepathology diagnosis and glass slide diagnosis) rate of 88.5% and they found a 96.5% concordance for clinically important diagnoses. Weinstein et al have reported a concordance rate of 99%.

HYBRID DYNAMIC STORE AND FORWARD SYSTEMS⁴

These systems are based on a combination of dynamic and static systems and are more cost-effective.

STATIC TELEPATHOLOGY

Static Telepathology being more relevant in the Indian context, because of lower cost of equipment and telecommunication costs and the lack of broadband linkages4, will be discussed in more detail. The workstation of a static telepathology system is comprised by :

Image Acquisition⁸

Any of the following methods of image capture may be used :

One can use conventional photography using a camera mounted on a microscope, and have the film developed and take prints of images, if that is the only method of image capture available and one does not want to invest further. In this case of course, one would end up spending extra time in having the film developed. One could also use analogue cameras or television cameras to capture images which have been used in the past for display purposes. As of today, however, digital cameras are being used increasingly since they are easy and more convenient to use and are available at increasingly economical prices. Both analogue and digital cameras capture images in the wave form (analogue images) using charged couple devices (CCDs), commonly known as microchips.

The important thing is that images have to be in the digital format in order to permit transfer to a computer, which is necessary to permit transmission of images using internet. While photographic images can be digitized using a scanner, images obtained from an analogue camera are converted into the digital format using analogue to digital converters (ADCs), digital cameras have inbuilt ADCs and therefore, give digital images immediately.

Digital Camera ^1,8

Digital cameras available these day are either single-chip cameras or three chip cameras, meaning thereby that they have either a single microchip or three chips inside. A single chip camera offers one third the luminance resolution, because the same CCD accommodates the three primary colours in alteration, whereas a three chip camera has three identical CCDs (each handling a single primary colour) and offers full resolution of an image, which is closest to the true image, this however, is almost triple the cost and there is also a proportionate increase in file size (as explained below).

It is recommended that a single chip camera with a resolution of 3 to 5 megapixels gives optimum images for routine static telepathology purposes.

Digital Imaging ^1,8

Digital images are either vector images or raster images. For Telepathology purposes, raster images (bitmaps) are use and will therefore, be discussed.

Colours and Resolution

- 16.8 (22^{4 )} million colours in a pixel (3 bytes, one each for a primary colour).

- the larger the no. of pixels captured per image, the higher the resolution.

Image Compression

Since large sized images come in the way of easy transmission, it is recommended that images of = 1 Megapixel (1MB) should be compressed. Image compression could be

lossy (20:1 or 30:1 or more, meaning thereby that significant data is lost in compression, or lossless (2:1). One of the more popular formats is the Joint Photographic Experts Group (JPEG), which is generally available with most currently available software. This is a lossy format. Other formats available are Graphics Interchange Format (GIF), Portable Network

Graphics (PNG), Tagged Image File Format (TIFF), Wavelet. However, these formats lack standardization and each one has its own applications. By and large the software that is supplied with the digital camera usually has a mode for resizing the images and compressing them. The figure shows the window for resizing in Olympus CAMEDIA software. Of late, the DICOM standards do apply to pathology imaging too.¹⁰

Processing And Optimization Of Images

Images stored in the memory/hard drive of the computer and packed in different formats can be improved or optimized. The contrast, brightness, tone of color, sharpness, size etc. using special programs such as Adobe PhotoShop, PhotoSuite, Picture It, etc. However, for diagnostic Telepathology purposes, the authors do not recommend any changes in the images after they have been captured. It is recommended that since digital cameras generally have software which allow prior changes, all adjustments should be made prior to capturing the images rather than later, for the fear that unintended artifacts may be introduced later. Image optimization should however, be practiced for improving images, when used for presentation, publication etc. The Telepathology Unit of Shree Krishna Hospital uses Olympus C4040 Zoom digital camera with the CAMEDIA MASTER software for opitimization of images.

TELEPATHOLOGY CONSULTANTS

Once imaging has been completed, the next step is to transmit the images to a Telepathology consultant. In static telepathology, it is of utmost important that there is a certain level of confidence and faith between the referring pathologist, the level of communication should also be good. This would help overcome the element of subjectivity to a large extent. Our centre has a collaboration with Tata Memorial Hospital, Mumbai and we therefore, preferentially refer our cases to this centre. There are however, a number of websites which offer Static Telepathology Services, some are free whereas, others charge for their services.

Etc.

TELECOMMUNICATION LINKS ¹¹

The advent of internet has brought about the current revolution in information technology and also therefore, medical informatics. For routine static Telepathology, a Plain Old Telephone Service (POTS) generally suffices, which is the usual dial-up connection which transmits data at 56Kb per second. This is the one mode which is easy available to most people and would especially apply to a pathologist in a remote area. Of course, the current availability of better connectivity in cities and digital subscriber lines coming in, data can be transmitted at a much faster rate. The table broadly shows various modes of obtaining internet connectivity with increasing rate of data transmission and therefore, faster speeds at which data could be transmitted. Satellite (V-SAT) is now gaining increasing popularity for effective data transmission and is also being used for the practice of telepathology.

TRANSMISSION OF IMAGES IN STATIC TELEPATHOLOGY¹

THE INDIAN SCENARIO

Telepathology is relatively new to India. A lot of efforts were put into making it popular with the launch of the website Telepathologyindia.com with prominent pathologists from all over the country on its panel. Up to 93 cases have been analyzed and rendered a telepathology diagnosis by the pathologists of Tata Memorial Hospital, Mumbai. Their rural centre being the Nargis Dutt Memorial Cancer Hospital at Barshi which is 70 kms from Solapur district and 500 kms from Mumbai. Desai et al ^12,13,14 concluded:

TELEPATHOLOGY UNIT : SHREE KRISHNA HOSPITAL

The Experience So Far

The first Telepathology Unit in the state of Gujarat was inaugurated in November 2002 at the Shree Krishna Hospital, Karamsad. The Unit was started in collaboration with Tata Memorial Hospital, Mumbai.The unit became functional in March 2002. It is equipped with an Olympus CX 41 research microscope, Olympus CAMEDIA digital camera model C 4040 Zoom with CAMEDIA MASTER software a preview monitor and PIV computer with internet connectivity. Karamsad is a village in Anand district. Geographically speaking, the hospital is at an approximate distance of 80 kilometers from Ahemdabad and 45 kilometers from Vadodara. Mumbai is at distance of 420 kilometers. The initial hurdles were related to lack of training and experience not only on part of the pathologist but also personnel supplying the equipment. Not only that, being situated in a rural area, the hospital had a dial-up connection (POTS), at that time. The year 2002, saw 3 cases being submitted for Telepathology consultation, to various centers, using an e-mail account with Indiatimes.com. However, in these three cases, the results were not encouraging and the cases invited only 'deferred diagnosis'. In fact, the cases, though they had been mailed from the account, were not received at all at one of the websites! The turn around time ran into days. In March 2003, the hospital acquired a fractionated leased line, with a bandwidth of 128 kbps. In the mean time, the pathologists at the centre also acquired better imaging skills with increasing familiarity with the software. 19 cases were submitted in the year, with a turnaround time of few hours to 3 days. There were occasions when transmission of images was difficult due to technical reasons. In 2004,till the time of this presentation, 34 cases have been submitted for a Telepathology diagnosis to Tata Memorial Hospital, with a turn around time of a few hours to 1 day in majority of the cases. Cases are sent as e-mail messages with attached images and requisition form. A substantial number of cytology cases have been submitted for diagnosis. The data is being analyzed.

THE INDIAN SCENARIO : PECULIARITIES

Indian conditions present their own peculiarities. They start with poor quality of preparation of basic material, which in fact comes in the way of routine histopathology practice. The basic requirement for the practice of Telepathology is good quality of prepared slides and a microscope with reasonably good optics. In our experience, this does come in the way of obtaining a diagnosis, when cases have to be deferred due to suboptimal quality of sections. Inadequate and inconsistent internet connectivity also comes in the way of an early diagnosis. There have been times when the server is down and it is impossible to transmit cases for technical reasons.

Utility

Is Static Telepathology useful ?

The Shree Krishna Hospital is a rural hospital with a full-fledged cancer centre. There is a young team of pathologists at the department of Pathology. There are occasions when the histopathology diagnosis does not match the clinical diagnosis, and it is desirable to have a second opinion. Many a time, a diagnosis of cancer is itself evoke a request for a second opinion by the patient. When a case is submitted for Telepathology consultation in such circumstances and the report is in agreement with that of the local pathologist, it is highly rewarding - it builds the confidence of the pathologist in himself and also of the clinician in the pathologist and of the patient in the institution. Needless to say, these patients generally stay on with the institution for further management.

There are of course, occasions when a diagnosis is difficult, under these circumstances Static Telepathology is an educational tool for the department.

The practice of Static Telepathology at the Shree Krishna Hospital has helped provide a rapid and expert diagnosis across geographic borders from the premier cancer centre of country at no extra cost rendering an economy of time and resources, which the rural poor of the region could certainly do with.

CONCLUSION

Practiced correctly, Static Telepathology is a useful tool for rendering an early, expert diagnosis (primary or second opinion) rendering substantial economy of time and resources and can prove to be a service, especially to cancer patients in rural areas, by saving them the psychological trauma of having to run from pillar to post for obtaining a diagnosis.

REFERENCES

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