Niche Adoption of Digital Pathology at UHN: From Frozen Sections to Primary Diagnosis

Dr. Andrew Evans MD PhD FRCPC

Staff Pathologist, Director of Telepathology

University Health Network, Toronto, ON, Canada

Overview

• WSI telepathology at University Health Network

how we started and why

how we have expanded our use of the technology

enabling sub-specialty pathology

• What we need to keep moving forward with this technology

• Move slides?

• Move pathologists?

• Telepathology? • Transmission of pathology images and patient

information for various clinical applications • Expanding list of clinical applications at UHN:

• Frozen sections (2004-present) • Consultation - local and international • Supporting transplant pathology programs • Quality assurance • Primary diagnosis (2012 - present)

Multi-Site Sub-Specialty Pathology

• Yes • 20% of my service work is done by WSI

• 80% is done with glass slides and a microscope

• WSI is used for clinical purposes on a regular basis by 40% of UHN pathologists

• We are living the adoption challenges!

Does UHN Still Use Microscopes?

• Full departmental consolidation at Toronto General Hospital (TGH) in early 2006

• No regular on-site pathologist at Toronto Western Hospital (TWH) as of 2004

TWH Frozen Sections: Challenges • Single pathologist traveling from TGH to TWH

• Inefficient - traveling and waiting • Disruptive to regular workflow at TGH • No consultation on difficult cases

Driven by a need - not a business opportunity with ROI

Telepathology at UHN: History

TWH Whole-Slide Imaging: October 2006-Present

• > 4000 frozen sections/3500 patients

• > 90% from neurosurgery

• 0-2% discrepancy rate

• 14-16 minute total turnaround time

• < 1-5% deferral rate

- 2 pathologists review all deferrals

10-12 minutes

1-3 minutes

Intra-Operative Consultations: Work Flow for Single Block Frozen Sections

Why Has This Worked at UHN?

• Started with a single clearly-defined application neurosurgical frozen sections

• Uncomplicated frozen section work flow

• Long development period with due diligence 18 months from initial meetings to go-live

time to build confidence and trust

• Implementation team

• Standard Operating Procedure (SOP)

Image Quality: The Importance of Good Histology

Poor slides = Poor image quality

20x scans – ask for 40x when necessary

• 10 episodes (0.2% of cases to date) requiring a pathologist to go to TWH

• Small pale pieces of tissue (x2)

• Excess mounting media (x1)

• Burned out light bulb (x1)

• Calibration errors (x5)

faded H&E test slides

aging light bulb

Episodes of Mid-Case System Failure:

www.blog.al.com/spotnews/2009

System Failure: Plan B

• Pathologist informs surgeon and goes to TWH if issue not resolved in 5 minutes

• A second pathologist works with the TWH histotechnologist in case the issue is resolved.

Frozen Section Telepathology: Remote Sites

©Google Maps 2008

Timmins: Variety of cases No on-site pathologist Two scanners Multiple connectivity

routes

Kingston: Neuropathology frozen

sections. Other pathologists on-site.

Transplant Telepathology at UHN: 2007-Present

Liver and kidney Ultra-rush biopsies, all hours of day and night Highly-nuanced reporting is expected Two pathologists cover each service

Kuwait Cancer Control Center (2012)

• First diagnosis made on scanned slide images (H&E, special stains/immunohistochemistry)

• Diagnostic information becomes part of the patient record

• Treatment decisions to be made based on this information

Primary Diagnosis By WSI

• American Telemedicine Association (2014)

• Royal College of Pathologists in Britain (2013)

• Canadian Association of Pathologists (2013)

• College of American Pathologists WSI Validation (2013)

• Others (Japan 2005)

Digital Pathology Guidelines

Self-Validation Studies: What is Learned?

• WSI can be used for making accurate and complete diagnoses

• What needs to be optimized in the histopathology laboratory to facilitate digital sign out

• Limitations • cases that require re-scanning

• cases to scan at 40X

• cases requiring deferral to glass slide review 5%

65 km/40 miles

Lakeridge Health-UHN • Sub-specialty reporting model • Common LIS with WSI integration • 300-400 slides/day sent to UHN • 50% done by WSI as of 2012

• Regional cancer centre • 25000 surgical

accessions/year • 5-8 pathologists on

site

Phased Implementation Strategy

• Start with most experienced users • GU, endocrine, liver, head and neck

• Attempt to scan all cases for these groups

• Review digital slides and sign out • request glass slides whenever it is required to sign

out a given case

WSI: Primary Diagnosis

758

10,430

22,271

239 2,211

4,385

0

5000

10000

15000

20000

25000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

# slides # cases

• October 2012 - October 2014 • 4385 cases (22,271 slides) scanned for primary diagnosis by WSI

2012 2013 2014

Transurethral Resection of Bladder Tumor

pT2

CIS LVI

Deferral to Glass Slides = 5% of Cases

• Learning curve issues/difficult cases - pathologists still establishing comfort level (80% of deferred cases)

• IT performance issues (15%)

• Sub-optimal image quality/soft focus in area of importance (4%)

• Things you cannot do digitally the way you would with a microscope (1%) - mitotic figures/HPF

Growing Pains So Far

1. IT infrastructure and computing power

2. Viewer stability and viewing speeds

3. Scanner issues

4. WSI – LIS interface and barcode issues

5. Hybrid glass slide – WSI workflow

Hybrid Glass Slide – WSI Workflow

• Varying levels of pathologist experience with WSI diagnosis • some defer to glass more frequently than others • pathologist duty roster changes

• Culture change - learning to use electronic work lists

• Special stains • when are they ready for review? • some special stains cannot be done at Lakeridge

Potential to forget about digital cases

Challenges Moving Forward

1. Cost

2. Getting past the hybrid work flow

3. Pathologist perception of inferior performance in terms of speed “it’s too slow and I’m too busy”

in part, due to inefficient use of the viewer

Use of WSI at UHN To Date

• We have used computer screens the same way we use microscopes. visual interpretation of H&E morphology

visual interpretation of immunohistochemsitry

• We need to introduce image analysis

do what cannot be done with human eyes and microscope

faster and more thorough - better patient care

Slide Review 36.0%

Other 16.0%

Reporting 34.6%

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 Time & Motion Study: Glass Slide Review (Stratman et al)

• Problematic for large cases and/or slides requiring a lot of panning and zooming

Input Devices

Concept of “pCAD” Automated, systematic slide review Construct a report as slides are reviewed Reduce the time spent on non-diagnostic work

Summary

• WSI telepathology at University Health Network

enabling sub-specialty pathology

how we started

how we have expanded our use of the technology

• What we need to keep moving forward with this technology

Acknowledgements

• Pathologists all of my colleagues Dr. Sylvia Asa – brought vision of telepathology to UHN

• Histotechnologists at UHN and its partner sites

• UHN IT, Lab Management and LIS Support – Michele Henry and Brad Davis – Peter Woo, Cecilia Lagmay-Traya and Hung Chow

• Lakeridge Staff – Alan Wolff, Jessica Hutton and Grant Johnson