Rapid Validation of Whole-Slide Imaging for Primary Histopathology Diagnosis

Abstract

Objectives: The ongoing global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic necessitates adaptations in the practice of surgical pathology at scale. Primary diagnosis by whole-slide imaging (WSI) is a key component that would aid departments in providing uninterrupted histopathology diagnosis and maintaining revenue streams from disruption. We sought to perform rapid validation of the use of WSI in primary diagnosis meeting recommendations of the College of American Pathologists guidelines.

Methods: Glass slides from clinically reported cases from 5 participating pathologists with a preset washout period were digitally scanned and reviewed in settings identical to typical reporting. Cases were classified as concordant or with minor or major disagreement with the original diagnosis. Randomized subsampling was performed, and mean concordance rates were calculated.

Results: In total, 171 cases were included and distributed equally among participants. For the group as a whole, the mean concordance rate in sampled cases (n = 90) was 83.6% counting all discrepancies and 94.6% counting only major disagreements. The mean pathologist concordance rate in sampled cases (n = 18) ranged from 90.49% to 97%.

Conclusions: We describe a novel double-blinded method for rapid validation of WSI for primary diagnosis. Our findings highlight the occurrence of a range of diagnostic reproducibility when deploying digital methods.

Keywords: Case management software; Digital pathology; Primary digital diagnosis; SARS-CoV-2; WSI validation; Whole-slide imaging.

Figure 1

Case selection and exclusion and scanning quality control process used in the study. IHC, immunohistochemistry; WSI, whole-slide imaging.

Figure 2

Distribution of digital cases (n = 171) by small (light gray) and large (dark gray) types (A) and numbers of slides per case (B) and by subspecialties (C) across study pathologists.

Figure 3

Distribution of percentage of agreement in 90 cases (1,000 samples) drawn from total (n = 171). A, Concordance rate counting minor and major diagnostic discrepancies, with a mean of 83.66 (95% confidence interval [CI], 83.49-83.83; range, 75.56-92.22). B, Distribution of concordance counting only major discrepancies, with a mean of 94.58 (95% CI, 94.48-94.68; range, 90-100).