Ten things you need to know about going 100% digital for primary histopathology diagnosis
Posted 21st November 2018 by Kieran Chambers
Digital pathology is based on creating a digital replica of the glass slide, called whole slide image (WSI). This image is then viewed in a computer screen, which eliminates the need for using a microscope. Can you imagine working in a glassless environment, with better ergonomics and being able to immediately find the slide you need?
At Granada University Hospitals – a network of four publicly-funded hospitals in southern Spain – our 23 pathologists have been diagnosing all our entire histopathology caseload using only digital pathology since September 2016. The microscope is a thing of the past, if you don’t do cytology! Overall, our pathologists feel better off, more efficient and happier with the change to digital diagnosis. Our experiences implementing and using digital pathology can be summarised in these 10 points.
1. Sample tracking is essential to go digital
Having at least some degree of sample tracking is mandatory to go 100% digital. Glass slides need to be tagged with Barcodes or QR codes, which permits their identification by the digital pathology system. With this, the IT system can keep track of at which stage the slide preparation is, and therefore all glass slides are accounted for. This is usually done by the laboratory information system (LIS). Tracking is the foundation upon which you build digital pathology.
2. Integration of the LIS and the digital pathology system is also essential
When digitising the large volume of slides routinely generated in clinical practice, the digital pathology system needs to be integrated with the LIS. This ensures that when a slide is scanned, it is given an identity so it can be assigned to the right case and the right patient. The integration between the digital pathology system and the LIS permits this to happen automatically.
3. Clean and Organised slides
Some changes in glass slide preparation are required. To minimise the number of scanning problems, slides need to be clean and dry, with well aligned coverslips and free of excessive mounting media. Also, the barcodes and QR codes need to be perfectly legible, to ensure the digitised WSI can be safely assigned to the right case and the right patient.
4. Getting the right scanner is vital
Going 100% digital requires a scanner with high throughput, capable of unsupervised overnight scanning, and that digitises the slide correctly the first time. Granada uses the Philips solution, whose scanner is capable of walk-away scanning, meaning no user intervention is required. Thus, histotechnicians can be freed to do other tasks in the lab. Image quality is essential, and scanning at 40x is a must for clinical use. Whereas many cases may be safely diagnosed at 20x, clinical routine practice requires the high quality images that scanning at 40x provides. This allows us to confidently rule out dysplasia or to assess intracellular structures, such as nucleoli, neuroendocrine chromatin, or to differentiate mitoses from apoptotic nuclei.
5. Consistency is vital for safe adoption
Validation. Ensuring that your diagnosis of the same lesion is consistent, whether you use digital pathology or conventional microscopy, is necessary for the safe adoption of digital pathology. Both the College of American Pathologists and the Royal College of Pathologists have published guidelines to ensure safe transition from the microscope to digital pathology. A good digital pathology system should provide clinical grade images of very high quality, so your diagnosis would be the same irrespective of whether you use a microscope or digital.
6. FDA Approved Systems
A FDA-approved system provides the peace of mind of knowing that your solution is capable of delivering clinical-grade images, and proven to be non-inferior to those of the microscope. The FDA approval process of the system in use at Granada University Hospitals demonstrated non-inferiority in challenging tasks, such as the detection of microorganisms like Helicobacter, and the diagnosis of lymph node specimens.
7. Low Power Images
Images at low power are better than what a normal microscope usually offers. The lowest power usually available in a regular microscope is 2.5x, but digital pathology can offer 0.5x or even 0.1x. Therefore, at just a glance, you get more context about the lesion, such as total extension, relationship with surgical margins, etc. This is important, since we all know that the majority of our diagnoses are made at low power.
8. It allows for a simplified working area
Pathologists prefer working digitally: clean, clutterless desks, tools that permit making easy and precise lesion and margin measurement. Also, all your slides are orderly displayed and easy to find when you need them. You can split your screen and compare several techniques at once, which is helpful when evaluating different CD expression areas in lymph node specimens or when assessing melanocytic marker expression. For these reasons, all 23 pathologists at Granada University Hospitals declared recently in an internal survey that they would rather continue using digital pathology than return to the microscope. It simply makes your life better!
9. It’s the foundation for computational pathology
Can you imagine your favourite movie in HD video and 5.1 surround sound, but then watching from a VHS videotape? The availability of a digital version of a glass slide enables the use of computational tools for image analysis, that will assist pathologists in doing their job.
10. Computational pathology will change, for the better, the practice of the profession
The use of computational and artificial intelligence tools will assist pathologists with some of the most repetitive and time consuming tasks, such as mitotic counting and sentinel lymph node screening. However, pathologists are not likely to be replaced by computers anytime soon. At the end of the day, the most valued intelligence isn’t precisely artificial.
Going 100% digital and substituting the microscope for the computer screen finally brings pathology to the digital era, which is something our colleagues in radiology did decades ago. Digitising your lab implies many challenges, so it’s best to associate with a vendor with a proven solution and a demonstrated success record. The multiple benefits associated with working digitally, plus the exciting new tools of computational pathology are changing the practice of the profession for the better. That has certainly been our experience at Granada University Hospitals. So much so, that we said goodbye to the microscope forever!
Juan Antonio Retamero Diaz is a Pathologist at Granada Hospital. He will present “Complete digital pathology for primary diagnosis: Thirty months’ experience at Granada University Hospitals, Spain” at the Digital Pathology & AI Congress.
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