Digital Whole Slide Imaging for Patient Care in Toronto

Dr. Andrew J. EvansStaff Pathologist & Associate Professor

Department of PathologyUniversity Health Network, Toronto, Ontario, Canada

Disclosure

• Leica Microsystems

• Aperio

• Vendor/client relationship only

UHN Whole Slide Imaging Telepathology

1) Primary frozen section diagnosis

2) Sub-specialty pathology service to hospitals in Northeastern Ontario

3) Maintaining 24/7 sub-specialty coverage of transplant pathology services

• No on-site pathologist

• 2-10 frozen sections

per week (mostly

neurosurgery)

University Health Network

~ 1 mile

TWH Frozen Sections: The Problems to Be Solved

• Single pathologist traveled to TWH– Inefficient process - traveling and waiting

– Disruptive to workflow – 99% of departmental activity occurs at TGH

• delays in regular sign-out affecting other UHN patients

– No possibility for consultation on difficult cases.• Compromised diagnostic accuracy• Unnecessary deferred diagnoses

Due Diligence

• In-house training and validation (18 months)

• Medical Malpractice Insurance Provider (CMPA)

• UHN Medical Advisory Committee

• Health Canada – Therapeutic Products Program– telepathology does not involve “medical devices”

• Surgeon Education

The Robotic System: November 2004-October 2006

• 350 frozen sections

• accurate

• deferral rate < 10%

• slow (~ 10 minutes/slide)

Whole-Slide Imaging: October 2006-Present

• > 1300 frozen sections

• 90% from neurosurgery

• 98.5-100% accuracy (month to month)

• 14-16 minute turnaround time

• 7.5% deferral rate

• 2 pathologists review all deferrals

Whole Slide Imaging Telepathology

• Easy consultation with colleagues – better for patient care

• Essentially no learning curve – transition from robotic in 1 month

Whole-Slide Imaging: Cases Requiring Re-Scanning

• Image quality is not a problem!

• < 2% of cases– poor-quality slide

• folds in tissue• section too thick• freezing artifact

• No difference with microscope

UHN Partnerships in Northeastern Ontario

• Timmins (2005) and Sault Ste. Marie (2006)

• Shortage of pathologists, no sub-specialists

• No pathologist in Timmins 1-2 weeks/month

• Glass slides shipped to UHN– Limitations:

• Frozen sections• Lost/damaged slides• Delays with transporting slides

Timmins & District Hospitals - April 2008

• consultations

• frozen sections> 60 patients

• completely digital

within 2 years

Google Maps 2008

> 400 miles

Sault Area Hospitals - October 2008

• consultations

Google Maps 2008

> 400 miles

Transplant Telepathology at UHN

• Orthotopic liver transplant program

• ~ 600 post-transplant biopsies/year– 2 – 5 urgent biopsies/week (same day or next

morning results)

Practical Issues: - 3 liver pathologists

- absence for CME activities

- consultation with on-call colleagues after hours

UHN Liver Transplant Whole-Slide Imaging Telepathology

• 31 biopsies– 17 for cellular rejection– 3 potential donor biopsies– 11 for non-transplant medical liver disease

• Hepatologists and surgeons highly satisfied with service

• 1 missed diagnosis: donor liver frozen section 1AT deficiency on paraffin sections requiring special stain– would not have made this diagnosis on the frozen section

with a microscope

Skin

Renal

Cardiac

Other Sub-specialty Consults

Whole Slide Imaging Telepathology:Summary of UHN Experience

• SAFE, RELIABLE and ACCURATE

• Tremendous value added:• Primary frozen section diagnoses• Consultations between colleagues• Providing timely service to remote hospitals• 24/7 support to transplant programs

• Similar “niche” applications in the United States most definitely exist.