Fast Forward: Digital Pathology Enhances Speed of Slide Review

Consultant Pathologist, Dr. Rebecca Millican-Slater

Rob Monroe, Chief Medical Officer, Leica Biosystems

It’s time to dispel the myth that slide review is slow with digital pathology, says consultant pathologist Dr. Rebecca Millican-Slater, the Lead Clinician for Cellular Pathology at the St. James’s University Hospital, Leeds, UK.

More than 5 years after first integrating digital into her routine clinical practice, Dr. Millican-Slater is surprised that some pathologists still think digital slide review is slower than with a traditional microscope.

“There is absolutely no way that you will find me going back to using a traditional microscope for routine reporting,” she says. “I would probably spend double the amount of time looking at a case if I had to use my microscope versus how quick and efficient I now am with our current digital reporting platform.”

Her perspective emerged from her experience in pilot studies at St. James’s, Leeds Teaching Hospitals NHS Trust (Leeds), which is part of the National Pathology Imaging Co-operative. Leeds began investigating the viability of using digital pathology for routine diagnostics in 2017, a time when the efficiency of digital slide review was an open question.

In the pilot studies, Dr. Millican-Slater and her colleagues closely examined digital’s impact on slide review activities, including primary diagnosis, second opinions, measurements, mitotic counts and annotations.

Case Review

Pathologists often quickly look through a case and decide which slides are most relevant to the diagnosis, then go back to [those slides] to take measurements and to perform a more detailed high-power review, explains Dr. Millican-Slater.

“Digital pathology uses viewing software that puts everything in focus simply by scrolling the wheel on my mouse or pressing a key on my keyboard,” said Dr. Millican-Slater. “Navigating is much quicker than using a traditional microscope, which requires a lot of physical manipulation of the glass slides: picking them up, placing them carefully on the microscope stage, changing the magnification lens and fine-tuning the focus, among other actions.”

With multi-slide cases, the time saved moving between the digitized slides is paramount. “I no longer have the time-consuming process of constantly swapping out slides. Rather, I can move from slide to slide by clicking a button and marking any areas that I find interesting with various annotation tools. The speed with which I navigate through all the slides of a case has proven to be transformational.”

Annotations

Another area of importance highlighted by Dr. Millican-Slater is how digital pathology enables quicker and clearer annotation and collaboration.

“I can mark areas of potential interest for our colleagues. For example, I can put a circle around an area of interest with a note to alert my colleague to the bit of the slide that I want them to look at or highlight in a report,” she says.

Side-by-Side Image Comparison

In addition to accelerating the pace of case review, the pilot studies found that digital pathology offers benefits not possible with traditional microscopy, such as side-by-side slide comparison.

“With digital pathology, I can be certain that I’m looking at exactly the same area of cells when doing a comparison as I can visualize more than one slide at the same time. On a traditional microscope, that’s simply not possible,” she notes. “Consider a common instance when a side-by-side view is warranted – when you see tiny foci of suspicious cells on a slide surrounded by normal or benign cells. In such an instance, immunohistochemistry is likely needed; when you interpret the immunohistochemistry as positive or negative, it is critical to look at the suspicious cells and not the background cells. With a standard microscope, I need to look at both slides multiple times in order to match up the correct area. Using digital pathology allows you to line up the slides perfectly and then scan round them simultaneously so you are very quickly assessing the correct cells – this is an important, timesaving benefit.”

Geoff Punshon, Training Manager, Cellular Pathology, The Leeds Teaching Hospitals NHS Trust

Transforming and Enhancing Pathology

Another benefit of digital pathology is its ability to support quick, accurate and reproduceable measurements and mitotic counts.

“One thing that we use a lot in histopathology reporting is measurements. With digital, I can quickly make multiple measurements, to find the nearest margin for example, and save them for later reference, compared to spending many minutes trying to get that degree of accuracy and that number of measurements with a light microscope.” She adds, “We also spend a lot of time searching and counting mitotic figures in tumors. Early in the roll-out of digital pathology, there was a concern that mitotic figures might be harder and more time-consuming to identify using a digital platform. This may still be the case with certain scanners and screens but without current set up at Leeds, I am 100 percent confident that any mitotic figures that I can see on a glass slide using my light microscope I can also see on the whole slide image on my computer screen.”

A 2022 review article examining the integration of digital pathology into clinical practice supports this perspective, highlighting “…evidence exists to show the non-inferiority of whole slide images to glass slides, however the real value in using digital pathology is not merely to replicate the microscope, but to offer ready access to digital slides from any location, innovative workflows, advancing pathology through clinical transformative solutions using machine learning and decision support tools.”[1]

Practically speaking, there are a number of actions to take if pathologists find digital review too slow, Dr. Millican-Slater advises. “For example, I would suggest they change their viewer (because there are viewers out there that are ready and optimized for clinical use), ensure network connections are up to speed, and experiment with various different hardware options (for example, a gaming mouse, a trackball mouse, a programmable gaming keyboard).”

The Leeds team documented their learnings and insights in the Leeds Guide to Digital Pathology volumes 1 and 2.

“Fairly quickly in our adoption of digital, it became apparent that we had a viewing platform that was responsive enough to be equivalent to a traditional microscope. When set up properly, there should be no reason why anyone would find digital pathology slower in comparison to a traditional microscope,” Dr. Millican-Slater concludes.


National Pathology Imaging Co-operative, NPIC (Project no. 104687) supported by a £50m investment from the Data to Early Diagnosis and Precision Medicine challenge, managed and delivered by UK Research and Innovation (UKRI)

[1] Matthew G. Hanna, Orly Ardon, Victor E. Reuter, Sahussapont Joseph Sirintrapun, Christine England, David S. Klimstra, Meera R. Hameed,Integrating digital pathology into clinical practice,Modern Pathology,Volume 35, Issue 2, 2022, Pages 152-164, ISSN 0893-3952, https://doi.org/10.1038/s41379-021-00929-0.

Dr. Rob Monroe

Dr. Rob Monroe is a pathologist currently serving as Chief Medical Officer for Leica Biosystems and Chief Scientific Officer, Oncology for Danaher Diagnostics. Prior to Danaher, Dr. Monroe served as Chief Medical Officer of Bio-Techne following the acquisition of Advanced Cell Diagnostics in 2016. Prior to Advanced Cell Diagnostics, Rob served in successive roles as Chief Medical Officer at BioImagine, a digital pathology start-up acquired by Roche in 2010, and VP of Laboratory Operations & Medical Director at Veracyte. During his industry career, Rob also co-founded OncoMDx, a molecular diagnostics laboratory subsequently acquired by Core Diagnostics in 2012 where he served as Chief Medical Officer of the molecular lab and an international digital pathology service. Before joining industry, Rob practiced pathology in the Central Coast of California following a Medical Scientist Training Program Scholarship at Harvard Medical School and residency training in Anatomic Pathology at UCLA and Clinical Pathology at Stanford. Rob is board certified in Cytopathology, Anatomic Pathology, and Clinical Pathology and holds a PhD in Genetics.

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