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David Snead on The use of digital pathology in the primary diagnosis of histopathology samples.

Recent developments in digital pathology enable the rapid scanning of microscope slides at high resolution, making the digitisation of histopathology slides for routine diagnosis purposes feasible. An important initial step in the wider adoption of this technology is the establishment of validation data assessing how effective pathologists are using digital workstations in comparison to conventional light microscopes and glass slides when examining cases for primary diagnosis. I will report on the first study sufficiently powered to demonstrate a statistically valid equivalent (i.e. non-inferior) performance of digital pathology (DP) against standard glass slide (GS) microscopy. This study examined a total of 3,017 cases were included, generating 10,138 slides, which when scanned resulted in a digital archive of 2.45 terabytes. As well as demonstrating non-inferiority of digital in comparison to glass slides the study was useful in establishing rules for slide scanning and identifying areas where digital pathology has limitations and needs to be used with caution.
Finally the presentation covers the impact adopting digital pathology will have on diagnostic laboratories, the economics of these changes and where these changes are most likely to benefit patients.

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David Snead on The use of digital pathology in the primary diagnosis of histopathology samples.

  1. 1. Digital pathology in routine diagnostic histopathology Dr David Snead University Hospitals of Coventry and Warwickshire NHS Trust and Centre of Excellence for Digital Pathology Coventry, UK.
  2. 2. Conflict of interests • Omnyx funding for validation trial • Omnyx/GE funding UHCW Digital Pathology Centre of Excellence
  3. 3. Introduction • 2011 UHCW entered an engagement with Omnyx Digital pathology • Whole slide imaging solution for diagnostic histopathology • Based on high throughput digital slide scanners and networked diagnostic workstations • Beta system tested in 2012 • Full system designed around the UHCW workload 2012
  4. 4. Requirements of a digital pathology solution • Rapid scanning • Integration with the laboratory LIMS • Stable • Fast data transfer for real time reporting • Validation - proven equity to light microscopy • International standard for digital archiving
  5. 5. Why digital pathology at UHCW? • Innovation • Local pathology network needs • Home working and remote reporting • Academic potential • Synergy with the University of Warwick computer science department • Enthusiastic consultant workforce • Training opportunities
  6. 6. Immediate challenges • Cost and return on investment • Validation • FDA decreed DP is not class 1 exempt. Pre-market testing is required • CPA require validation against existing technology • None inferiority study designed • Audit meeting variations used as benchmark of internal variation
  7. 7. Slide Review 36.0% (1:56:13) Other 16.0% (0:51:43) Reporting 34.6% (1:51:38) Organizing Cases 24.1% (0:10:25) Querying for Cases 18.5% (0:07:59) Waiting for Delivery 11.2% (0:04:49) Matching 10.5% (0:04:32) Searching for Cases 9.4% (0:04:04) Transporting Cases 9.2% (0:03:58) Other 17.0% (0:07:21) Workflow Opportunities 100% (0:43:09) 13.4 % Pathologist T&M Study Results Breakdown of Workflow Opportunities
  8. 8. Pre-allocation of specimens Push system
  9. 9. Improved workflow efficiency Pull system
  10. 10. CWPS MDT review
  11. 11. Validation study power calculation
  12. 12. Validation study design • Double reporting • Glass first digital second • Minimum of 3 week washout period • Compare reports to detect differences • Steering group meets fortnightly to assess and classify differences • “Ground truth” assigned to one or other platform • Study closed when3014 cases were double reported
  13. 13. Validation study methods • Sequential cases in all subspecialties selected from filing • Slides received • Cleaned / re-coverslipped • Scanned • Released to individual pathologists work bench and subspecialty benches • 14 pathologists involved • 1/3 cases reported by the same pathologist 2/3 by different pathologists
  14. 14. Cases 3,017 Slides scanned @ x40 (0.274um/pixel) 10,138 Slides scanned @ x60 (0.137um/pixel) 1,384 Data 2.45 TB Estimated annual slide archive size 22TB Scan speed per slide 90 seconds
  15. 15. 96 97 98 99 100 Percentage All data Same pathologists Different pathologists All data Same pathologists Different pathologists 3017 1009 2008 3017 1009 2008 99.3 (99, 99.6) 99.1 (98.5, 99.7) 99.4 (99.1, 99.7) 97.6 (97.1, 98.2) 97.2 (96.2, 98.2) 97.8 (97.2, 98.4) Data used n Percentage (95% Confidence interval) Completete concordance or no clinical difference Completete concordance
  16. 16. X60 (0.137um/pixel) X40 (0.274um/pixel)
  17. 17. Problems • Speed of streaming • Tiles out of focus • Colour reproduction with DPAS stains • Screen fatigue
  18. 18. Challenges for routine practice • Front and back end interface with LIMS needed • Develop scanning rules • Re-work laboratory protocols • Improve section quality and tissue mounting • Maintain streaming speed within the departmental security protocol • Some things will still need glass • Polarisation • Cytology • Over sized blocks • Low grade dysplasia • X100 oil (scanty organisms)
  19. 19. Positives • Scan speed excellent mean around 90 seconds per slide • Image quality • Workflow software • Very easy to use system • Fits well in laboratory workflow • Stable • Excellent support
  20. 20. What does digital pathology offer? • Economic advantages • Increase efficiency of pathologists • Reduce turn around time to report cases • Improved review of cases including MDT/Tumour board review • Quality advantages • Reduced error rate • Increased subspecialisation • IHC scoring and indexing • Tumour grading / dysplasia grading • Cancer finder
  21. 21. Remote reporting • RAS token remote login • Ultra and Omnyx accessed through VRN • Dragon voice recognition installed • Backlogged cases available to report • Report entered in and authorised • Additional requests made via Ultra
  22. 22. Flexible workforce • 39,000 surgicals • 17 consultants (2,300 per wte) • 14 in post (12.5 wte) (3,120 per wte) • Outsourcing backlog to locums • £30 per case • Avoids employment costs i.e. PDP, appraisal, prospective cover, sick leave, maternity leave etc.
  23. 23. Algorithms in development • Improved accuracy and patient safety • Cancer grading tool prostate, breast, and bladder cancers • Cancer finding tool, region of interest alert • Alerts for slides or tissue samples not examined • Overlay tool intelligently identifies regions of interest in sequentially cut sections • Automation downstream quantitative ICC e.g. ER, PR, Ki67, HER2 • Quantification of tumour volume for molecular analysis
  24. 24. Digital pathology centre of excellence • Mitotic count tool 3rd AMIDA Grand Challenge Nagoya 2013 • Nuclear grading tool 1st MITOS-Atypia 2014 Challenge • Gland segmentation competition (GlaS) MICCAI Munich Conference Oct 2015 • Tumour grading tool • Cancer finding tool • IHC slides with quantitative scores • Resection margin, depth of invasion exported directly to report Korsuk SirinukunwattanaNasir Rajpoot Adnan Mujahid Violeta Kovacheva Nick Trahearn
  25. 25. Acknowledgements • Aisha Meskiri • Yee Wah Tsang • Klaus Chen • Bidisa Sinha • Sari Suortamo • Yen Yeo • Elaine Blessing • Shatrugan Sah • Kishore Goparlakrishnan • Emma Simmons • Hesham El Daly • Emma Simmons • Sarah Read Jones • Ian Cree • Peter Kimani • Ric Crossman

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