Whole‐slide imaging at primary pathological diagnosis: Validation of whole‐slide imaging‐based primary pathological diagnosis at twelve Japanese academic institutes

TLDR

Whole‑slide imaging has been used for primary pathological diagnosis, yet no Asian studies have reported on its validation. The study retrospectively analyzed 1070 WSI specimens from 900 biopsies and small surgeries across nine hospitals, with nine trained pathologists reviewing digitized images and then conventional glass slides, and discrepancies were evaluated and re‑reviewed. Major discrepancies occurred in 0.9% of cases and minor in 3.5%, but most major discrepancies agreed with microscopy, and no factors influenced discrepancy rates, supporting routine use of WSI for primary diagnosis.

Abstract

Several reports have demonstrated the use of whole‐slide imaging (WSI) for primary pathological diagnosis, but no such studies have been published from Asia. We retrospectively collected 1070 WSI specimens from 900 biopsies and small surgeries conducted in nine hospitals. Nine pathologists, who participated in this study, trained for the College of American Pathologists guidelines, reviewed the specimens and made diagnoses based on digitized, 20× or 40× optically magnified images with a WSI scanner. After a washout interval of over 2 weeks, the same observers reviewed conventional glass slides and diagnosed them by light microscopy. Discrepancies between microscopy‐ and WSI‐based diagnoses were evaluated at the individual institutes, and discrepant cases were further reviewed by all pathologists. Nine diagnoses (0.9%) showed major discrepancies with significant clinical differences between the WSI‐ and microscopy‐based diagnoses, and 37 (3.5%) minor discrepancies occurred without a clinical difference. Eight out of nine diagnoses with a major discrepancy were considered concordant with the microscopy‐based diagnoses. No association was observed between the level of discrepancy and the organ type, collection method, or digitized optical magnification. Our results indicate the availability of WSI‐based primary diagnosis of biopsies and small surgeries in routine daily practice.