Verification and Validation of Digital Pathology (Whole Slide Imaging) for Primary Histopathological Diagnosis: All Wales Experience

M Babawale; A Gunavardhan; J Walker; T Corfield; P Huey; A Savage; A Bansal; M Atkinson; H Abdelsalam; E Raweily; A Christian; I Evangelou; D Thomas; J Shannon; E Youd; P Brumwell; J Harrison; I Thompson; M Rashid; G Leopold; A Finall; S Roberts; D Housa; P Nedeva; A Davies; D Fletcher; Muhammad Aslam

doi:10.4103/jpi.jpi_55_20

Verification and Validation of Digital Pathology (Whole Slide Imaging) for Primary Histopathological Diagnosis: All Wales Experience

J Pathol Inform. 2021 Jan 23:12:4. doi: 10.4103/jpi.jpi_55_20. eCollection 2021.

Authors

M Babawale¹, A Gunavardhan¹, J Walker², T Corfield¹, P Huey¹, A Savage¹, A Bansal¹, M Atkinson¹, H Abdelsalam¹, E Raweily¹, A Christian³, I Evangelou³, D Thomas³, J Shannon⁴, E Youd⁴, P Brumwell⁴, J Harrison⁵, I Thompson⁵, M Rashid⁵, G Leopold⁶, A Finall^{6

7}, S Roberts⁸, D Housa⁹, P Nedeva⁹, A Davies¹, D Fletcher¹, Muhammad Aslam¹

Affiliations

¹ Department of Cellular Pathology, Glan Clwyd Hospital, Betsi Cadwaladr University Health Board, Bodelwyddan, Wales.
² Department of Anaesthetics, Gwynedd Hospital, Betsi Cadwaladr University Health Board, Bangor, Wales.
³ Department of Histopathology, University Hospital of Wales, Cardiff and Vale University Health Board, Cardiff, Wales.
⁴ Department of Histopathology, Royal Glamorgan Hospital, Cwm Taf University Health Board, Rhondda Cynon Taff, Wales.
⁵ Department of Histopathology, Royal Gwent Hospital, Aneurin Bevan University Health Board, Newport, Wales.
⁶ Department of Cellular Pathology, Morriston Hospital Swansea Bay University Health Board, Port Talbot, Wales.
⁷ Abertawe Bro Morgannwg Health Board, Port Talbot, Wales.
⁸ Department of Cellular Pathology, Singleton Hospital, Abertawe Bro Morgannwg Health Board, Port Talbot, Wales.
⁹ Department of Histopathology, Glangwilli Hospital, Hywel Dda University Health Board, Carmarthen, Wales.

Abstract

Aims: The study is aimed to verify Aperio AT2 scanner for reporting on the digital pathology platform (DP) and to validate the cohort of pathologists in the interpretation of DP for routine diagnostic histopathological services in Wales, United Kingdom.

Materials methods and results: This was a large multicenter study involving seven hospitals across Wales and unique with 22 (largest number) pathologists participating. 7491 slides from 3001 cases were scanned on Leica Aperio AT2 scanner and reported on digital workstations with Leica software of e-slide manager. A senior pathology fellow compared DP reports with authorized reports on glass slide (GS). A panel of expert pathologists reviewed the discrepant cases under multiheader microscope to establish ground truth. 2745 out of 3001 (91%) cases showed complete concordance between DP and GS reports. Two hundred and fifty-six cases showed discrepancies in diagnosis, of which 170 (5.6%) were deemed of no clinical significance by the review panel. There were 86 (2.9%) clinically significant discrepancies in the diagnosis between DP and GS. The concordance was raised to 97.1% after discounting clinically insignificant discrepancies. Ground truth lay with DP in 28 out of 86 clinically significant discrepancies and with GS in 58 cases. Sensitivity of DP was 98.07% (confidence interval [CI] 97.57-98.56%); for GS was 99.07% (CI 98.72-99.41%).

Conclusions: We concluded that Leica Aperio AT2 scanner produces adequate quality of images for routine histopathologic diagnosis. Pathologists were able to diagnose in DP with good concordance as with GS.

Strengths and limitations of this study: Strengths of this study - This was a prospective blind study. Different pathologists reported digital and glass arms at different times giving an ambience of real-time reporting. There was standardized use of software and hardware across Wales. A strong managerial support from efficiency through the technology group was a key factor for the implementation of the study.

Limitations: This study did not include Cytopathology and in situ hybridization slides. Difficulty in achieving surgical pathology practise standardization across the whole country contributed to intra-observer variations.

Keywords: Concordance; diagnosis; digital pathology; glass slides; ground truth; light microscopy; scanned slides/whole slide imaging; validation; variances/discrepancies; verification.