Facing the Digital Future of Pathology

Digital pathology is making its presence felt all over the world. For some pathologists, it’s life; for others it is something to be viewed with skepticism.

Earlier this year England’s National Health Service (NHS) published an overview of its National Pathology Program: “Digital First: Clinical Transformation through Pathology Innovation”(1). The document sets out how healthcare could apply new technology to help meet increasing demand, which is particularly pertinent for a health system that is financially stressed. Jo Martin (national clinical director of pathology for NHS England, and professor of pathology at Queen Mary University of London) prefaces by stating, “Pathology is leading the way in the use of digital technology, with the automated disciplines at the leading edge.” Martin highlights how, in her own practice, technology has had a huge impact on improving communications, procedures, workload and quality.

The document is full of examples and references that support use of the technology, but it is clear that bridges must be crossed before we witness widespread adoption.

The plus points

You can do a lot more with digital pathology than you can with manual microscopy: instant sharing of results with multiple departments and colleagues; being able to include digital images with your pathology report; using computerized quantitative analysis for prognostic scores; removing the danger of breaking glass slides in transit; remotely interpreting frozen sections and so on. These advantages can all help speed up diagnostic accuracy or turnaround times.

It goes without saying that quality assurance (QA) is much improved with the technology – manual errors are reduced through its ability to perform automatic case reviews and tracking of slide assessments for completeness. Image analysis efficiency, precision and reproducibility are also much improved compared with manual microscopy (2, 3).

But, it’s not only those of you who work in the clinical setting who have gained. For example, the inherent robustness and longevity of digital slide teaching sets are a big advancement on glass slides, which can fade, break or be misplaced. Other advantages include the ability to scan a single tissue sample to provide slides for numerous teaching classes; it also enables students to experience a wider range of cases.

Whichever way you look at it, digital pathology technology is significant and the market for it is growing (see “The Digital Pathology Market” below). The big question: why is there an apparent reluctance to implement it in every hospital? It seems there is no single, clear-cut answer. Indeed, The Pathologist welcomes your comments, which we hope you will be happy to share with the whole pathology community.

Problems and challenges

Pulmonary pathologist Timothy Craig Allen goes some way to explaining the apparent reluctance by highlighting a number of challenges that face digital pathology, including legal, privacy, security, confidentiality, and standard of care issues, in a recent article (4).

In practical terms, however, one of the first hurdles to overcome is the amount of bench space needed to site a system. Also, the workflow is something quite different; it isn’t simply a matter of scanning slides, digitizing them, adding meta data and sending them to a computerized library to share with others. The very high resolution, highly detailed images result in huge files (think gigabytes rather than megabytes), so storage is also a real challenge. And because most files are in proprietary formats, you can’t open them using standard software.

In addition, you have to consider how you make the files viewable to others and whether or not another pathologist will see the slides in exactly the same way, if they are using different monitors.

Perhaps more fundamentally, the quality of the image may not be assured. For example, the scale of an image displayed on a computer monitor is different to the same image viewed through a path lab microscope. And optical resolution is different from digital resolution, so correct equipment setup is a priority. The benefit of using a monitor, however, is a better field of view and the ability to view more slides at once, as well as being readily able to move them around to see more of the tissue directly on screen.

The strain on a lab’s IT system – and the other systems it connects with – is another area of concern, with reliable network and Internet bandwidth being important factors.

Burgeoning patents

Patents have created unwanted obstacles too. As new technologies emerge, inventors and developers scramble to protect intellectual property. Even now, digital pathology patents run into several hundred according to research by Ioan. Cucoranu et al. (5). The group’s investigation shows that the number of patents has quadrupled over the last 10 years, which goes hand in hand with developments in the field. Telepathology and whole slide imaging (WSI) account for the majority and there is a growth in digital image analysis and CAD. The researchers found that although the process of securing a patent can be lengthy, the abandonment rate was 10.6 percent, which is relatively low.

The problem is the potential conflict between patents and standards that may arise when the implementation of standards necessitates use of technology protected by patents. As the market expands, we should expect to see growth in the number of patents too, and that will not help the problem. On a positive note, some manufacturers have recognized the need for an open playing field in terms of standards. Leica, for example, is helping to clear the way by making its Aperio technology patents, which cover technology included within international standards, available free of charge to other manufacturers.

The need for standardization

In general, pathologists are very good at implementing standardized technology, and a lot of what is already done in the path lab is automated. For example, barcoding helps with accurate labeling and identification of samples and with workflow. Laboratory information management systems (LIMS) are the norm and allow primary and secondary care clinicians to order tests, and view the results, electronically.

In terms of standards for digital medical images and related information, DICOM (Digital Imaging and Communications in Medicine) is the recognized international standard and is identical to ISO 12052. Published in 1993, the standard is implemented in almost every radiology, cardiology imaging, and radiotherapy device and increasingly in devices in other medical domains (for example, ophthalmology and dentistry). DICOM Supplement 145 is applied to WSI and defines the archiving and storing of image files. Integrating the Healthcare Enterprise (IHE) is an anatomic pathology group initiative that has also defined a standard that covers the manner in which systems communicate with each other.

Though some progress is being made in the development of standards, an open digital image format standard is yet to emerge, with vendors locked into proprietary imaging technologies. This creates problems with compatibility both backwards and forwards, which is something that Marcial Garcia Rojo discusses in “The Digital Pathologist’s View”, here.