Demand for digital pathology

There are three regional hospitals in Jönköping county, Sweden, but only one of them, the Ryhov Hospital in Jönköping, has a histopathology department. The other two hospitals (in Eksjö and Värnamo) do not have histopathology departments on site, but they perform breast surgery using modern intraoperative sentinel node sampling (with frozen section).

The distance made it impossible to do frozen section examinations, so a digital pathology system was implemented. Sweden, like many other countries, is short on pathologists so several histopathology departments try to recruit specialists from abroad as a last resort. In the majority of cases, this raises other (primarily integration) issues, in WORKING SMARTER 40 January 2015 Number 169 The Bulletin of The Royal College of Pathologists particular if the specialist pathologist has a family. One of this article’s authors is András Zábó as a Swedish-speaking Hungarian pathologist who came to work in in Ryhov Hospital in 2007. For the first two years, he worked three weeks every month in the hospital as a locum and spent one week with my family. Although the hospital offered a full-time post, it was declined because of his family, and in 2010 he returned to Hungary with his family. However, he proposed to do his tasks from Hungary by means of telepathology and the hospital accepted the proposal.

Technical background

A VPN connection SITHS-card authentication was set up. This allowed open use of the Council’s own Windows desktop, folders and applications, effectively equivalent to the user working on site. The only drawback with that is that the bandwidth could cause limitations in the user experience, in particular when using locally installed applications on the working computer, with high dependency on fast database communication.

We used a Citrix solution to access the laboratory information system with dictation support (Speech Mike). The slides were scanned by a Scanscope XT scanner, at magnification of x20 lens, but were rescanned using x40 later if requested. Sections for Helicobacter identification were scanned at x40 magnification.

The database interface (Spectrum) is a web-based tool for administration and a user interface for opening the scanned slides with ImageScope thin client. Storage for scanned slides was a 3.5 TB SANsolution, enabling slides to be kept for three months, although it is possible to expand the storage capacity.

To simplify the user experience and expand the possibility of distance work, we are now looking for a solution where the user is not tied to a specific computer and is able to access slides directly from LIS in our Citrix environment. The remote reporting station was a laptop with a 24” monitor (1920x1200), dock, mouse and keyboard, with a webcam to facilitate clinicopathological conferences. A 25 MBps boadband connection was set up.

The work process

Histology sections are put through the scanner by an administrator, who also completes a case list in Excel format, which will be used by the remote pathologist for reporting. The request forms are accessed from the pathology database, where the previous histology results are also accessible. After checking, the case is dicated by the pathologist, then transcribed by typists and finally authorised remotely by the reporting pathologist. If the case requires further work, it is requested via the Excel case list.

The potential requests include requests for re-scanning for technical reasons (blurred, out of focus image, incomplete scan), if further work is needed (special stains, immunohistochemistry) or if specialist (e.g dermatopathologist) opinion is needed.

The department has three priority categories:

1. urgent, to be reported instantly or ASAP

2. to be reported within 5 to 10 working days

3. to be reported within 10 to 20 working days.

Priority 1 (urgent) cases are not assigned to the remote pathologist. The vast majority of such cases require immunhistochemical tests (probably in multiple and sequential steps, where multipleslide scanning may significantly impact the turnaround time.

Priority 2 cases (to be replied within 5 to 10 working days) are highlighted in bold and red, so the remote pathologist can prioritise those cases.

Case consultation There are cases where pathologists are required to consult with their colleagues. At the host department this is conducted in the traditional manner: either by handing over the slides or by personal or conference-type discussion of the cases, usually daily. This can be difficult with telepathology, but the difficulties are solved by technology.

It is usually done via email, and getting the original slides to the other pathologist from the departmental archive. In certain biopsy cases (primary malignant diagnosis leading to extensive surgery), we operate a double-reporting system for quality control. If this is the case, the remote pathologist requests peer review from a colleague the same way as second-opinion requests.

The colleague’s consent is recorded in the departmental database. If there is no agreement, the case will be referred for internal consultation. If the diagnostic issue cannot be resolved by an internal consultation, the case will be referred to a tertiary specialist (usually a university institution).

Their opinion is also entered and documented in the histopathology database. The administrator then informs the remote pathologist, who reviews the findings and opinions, and compiles the final diagnosis. Special considerations of digital pathology reporting Due to the lack of physical presence in the pathology department, the remote pathologist is unable to participate in some of the activities, such as autopsy, cut up and clinicopathological conferences. Where possible, we aim to adhere to the principle of ‘everyone reports their own cutup’. This is especially applicable to large excision specimens, where the macroscopy is essential for the correct reporting.

So what cases are left for remote pathologists?

There are cases which do not require the pathologist’s physical presence for macroscopic assessment (i.e. where cut up or putting specimens into casettes is performed by biomedical scientists or advanced practitioners). These include gastrointestinal biopsies, skin excisions, thick-needle prostate biopsies, gynaecological curettings, biopsies and cervical loop excisions, head and neck (ENT) or pulmonary biopsies, bladder biopsies, lymph nodes as well as appendectomy, cholecystectomy, myomectomy and uterine prolapse. All of the above can be also referred to as minor interventions. In addition, we assign technicians to perform cut up on total prostatectomy specimens in accordance with the protocol. However, as they contain full cross-sections, which are large, they cannot be scanned.

Can digital pathology be used as a daily routine?

Based on five years of experience, our answer is yes, it can be used. But what are the advantages and drawbacks?

Benefits 

• It maybe be a potential solution for helping local pathologists: connection can be established between two locations (in our case, two countries) or neighbouring institutions to facilitate instant consultation. However, it is important that both participants should also be experienced in assessment of digital slides.
• Ergonomic work conditions: we know of a pathology department in a Swedish hospital which has opted to digitalise about 85% of the annual histological materials because one pathologist had difficulties sitting at the microscope in a stiff posture due to cervical hernia. This solution enabled him to return fully to his job.
• Accurate measurement (even to a precision of 0.001 mm if needed) when measuring excision margins, malignant melanoma thickness, prostate cancer dimension, or distance between a tumour and the resection line.
• It facilitates easier identification of features on sections that require discussion.
• It makes orientation and navigation of the whole section easier.
• It also makes demonstration easier and faster at clinicopathological conferences.

Drawbacks

Disadvantages may include the following.

• Work pattern: some pathologists are used to their own microscopes, and like to work in isolation to resolve complex cases in their own office. Although this process allows examination of microscopic detail in depth, the vast majority (ca. 90–95%) of the person’s field of view is filled by what is seen through the microscope. In other words, 90–95% of the information perceived covers the section itself and nothing else. In comparison, a histological image projected to a screen occupies less than 20% of the field of view, causing a false perception of the amount of information, the view seen on the monitor not being sufficient or detailed enough. But if we turn this around, what you see in a microscope as a dot may be enlarged on a screen, appearing as big as 1 cm.
• Resolution: people can and should get used to digital views. It is essential to identify the same area and cells both in the microscope and on the screen and they have to be compared against each other. It might show differences in shape, colour, hue and colour intensity, but these can be learnt and adapted to, just like people get used to new microscopes.
• It is impossible to adjust sharpness/depth using the micrometre knob. But is that necessary at all? Nonetheless, that’s a good point – a virtual section cannot give you the same feeling. However, this concept is currently under development, and some systems offer z-stacking.
• How is the digital image so sharp? During the scanning process, the scanner program constantly adjusts the focus to all areas. This helps to eliminate the unevenness/bumpiness of the surface of the section. The program then merges these captured tiles (which are individually sharp) into a sharp composite image.
• Large investment is required for virtual section storage – though one may disagree. The need for digital image storage possibly originates from radiology practices where the original test subject (i.e. the patient) leaves the clinic, so the digital image should be preserved for years. When it comes to pathology, the original ‘subject’ (i.e. the slide or the block) can be retrieved from the department’s archive at any time. We digitally archive cases for approximately three months. All original sections are archived just as we have done in the past, but this may be subject to change with storage getting cheaper year on year.

The work done in the the past five years included 11490 histological tests (35500 digital slides) under the circumstances described above. From our experience, more than 1000 km distance between Jönköping and Budapest has not slowed down the work process, nor has it revealed any professional issues directly attributable to the digitisation technology itself. Based on the above arguments, we believe that telepathology as a digital histological method can effectively be implemented in hospitals’ daily routine.