Under the microscope: Exploring the potential of digital pathology

The term digital pathology describes the acquisition, management, sharing, and interpretation of pathology information — including slides and data — in a digital environment. Digital pathology is centered around the use of high-resolution digital slide images which are created using whole slide imaging scanners and then viewed on computer screens or mobile devices. Over the last two decades, regulatory and technological advancements have made it easier than ever for pathology labs to embrace the opportunities offered by digital pathology.^1,2,3

While the earliest digital microscope systems took over 24 hours to scan a single slide,⁴ a modern digital pathology scanner can produce high-resolution, high-quality images in under 1 minute per slide.⁵ Furthermore, ancillary technologies that support the digital pathology workflow, such as data storage and computational technologies have become more sophisticated and less expensive.^1,6

A series of parallel developments spearheaded by regulatory bodies in the US and the EU, including the approval for primary diagnosis to be conducted on computer monitors using digital pathologic images, have provided additional momentum to the digital pathology movement.^2,3

Looking to the future, digital pathology companies are working on sophisticated artificial intelligence (AI) algorithms designed to further enhance the digital pathology workflow. These developments are expected to create a paradigm shift in the way that pathologists carry out their day-to-day work.

While much of the current discussion around digital pathology looks towards its partnership with artificial intelligence, digital pathology offers a wide range of benefits. 

1. Remote slide access and facilitated collaboration: A pivotal benefit of digital pathology, with important repercussions for patients, is the ability for digitalized slides to be viewed both locally and remotely.⁷ With digital pathology, cases can be shared rapidly between pathologists, allowing an expert secondary opinion to be gained in seconds.⁸ This is especially important in areas where few specialists are available, as it supports pathologists in making an accurate diagnosis.^7,8 Furthermore, eliminating the need to package and send slides between institutions cuts waiting times for patients.^9,10
2. Integrated data management: Labs employing digital pathology can expect meaningful increases in efficiency and a streamlined workflow compared with traditional approaches.^7,11,12 A substantial portion of these increases can be attributed to the use of digital pathology software supported by complimentary features like slide barcoding.⁷ Digital pathology software streamlines the organization, storage, and retrieval of digital slides and associated patient data. It can be used to assist laboratory managers with managing and assigning workloads.⁷ Concurrent use of slide barcoding reduces the risk of slide misidentification and allows specimens to be tracked electronically through the laboratory.⁷
   
3. Enhanced image analysis capabilities: Digital pathology imaging offers the ability to zoom and explore multiple-angle views of slides. Slides can also be viewed side by side to facilitate their interpretation.¹⁰ Digital annotations can be added to slides by the pathology team, with the compiled annotations appearing in a convenient dashboard view. Advanced image analysis and pattern recognition algorithms are also shown directly on screen and areas of interest are automatically identified. Image analysis tools can also assist pathologists in measuring biomarkers and providing quantitative data. These functions support pathologists in performing rapid, accurate and objective evaluation of samples.⁷
4. Archiving and long-term preservation: Digital slides can be securely stored and archived in digital repositories, reducing concerns about loss or degradation of physical slides. While this ensures pathology specimens can be preserved over the long-term, it also supports teaching.¹⁴ Efficient digital archiving also enables easy access to historical cases, facilitating retrospective studies and quality assurance initiatives.

Due to the increases in efficiency and operational utility associated with digital pathology workflows, laboratories can realize significant cost savings following their implementation.^7,10,11,15 A study from a high-volume tertiary care cancer center in the US estimated $1.3 million of savings over a 5-year period following implementation of digital pathology workflow.¹¹ In another recent study from a Russian laboratory, profitability was demonstrated 2 years following the implementation of a digital pathology workflow, with an average operating margin of 40%.¹⁵

Primarily, savings arise as the management and administration work associated with the use of glass slides is drastically reduced.^7,11 In addition to reduced labor costs, vendor services such as transport of slides are decreased and a reduction in the requests for ancillary services such as immunohistochemical staining have been observed.^7,11 As pathologists have the opportunity to work remotely, savings related to reductions in laboratory and office space may be achieved. Another element of cost savings can be attributed to fewer occurrences of under- or over-treatment by oncologists, as digital pathology improves their ability access to second opinions from remote specialists.⁹

AI-based image analysis has already shown potential in the radiology and cardiology fields and its application to pathology is an active area of research.⁶ The wealth of information provided by digital images, including the presence of color and the availability of information at different scales are likely to make pathology a frontrunner in using AI to support clinical decision making.⁶ Taking oncology as an example, AI algorithms are already able to identify estrogen receptor positive and negative tumor cells and determine HER2 gene status using digital slides.¹⁶

A major advantage of AI in the anatomical pathology lab is that it can free up highly trained pathologists from routine and repetitive work.¹³ Examples of areas in which AI could assist pathologists include searching lymph nodes for cancer, time-consuming quantification and qualification tasks such as quantifying fat in the liver, or automated ordering of further tests on specimens prior to pathologist review.^7,13

The optimization of the digital pathology workflow using AI is also being explored. For example, AI will be used to perform color normalization of digital slides, or to identify out of focus areas on slides and prompt the slide scanner to add additional focal points in these regions.⁶

Perhaps the biggest impact of AI in the digital pathology workflow will be its ability to connect slide data to other complementary sources of clinical information, including medical history.^6,17 While supporting more accurate diagnoses and positioning pathologists at the forefront of precision medicine, it could also push the development of novel diagnostic and prognostic tools.^6,17

Digital pathology is an exciting frontier that offers a wealth of benefits for pathologists, healthcare institutions and patients alike. In addition to supporting pathologists with clinical decision making, digital pathology workflows offer significant efficiency and cost savings. 

In the future, digital pathology in combination with AI will orient the pathologist to the forefront of precision medicine, providing them with cutting-edge tools and marking a new era in the pathology profession.