Department Wide Validation in Digital Pathology—Experience from an Academic Teaching Hospital Using the UK Royal College of Pathologists’ Guidance

Abstract

Aim: we describe our experience of validating departmental pathologists for digital pathology reporting, based on the UK Royal College of Pathologists (RCPath) “Best Practice Recommendations for Implementing Digital Pathology (DP),” at a large academic teaching hospital that scans 100% of its surgical workload. We focus on Stage 2 of validation (prospective experience) prior to full validation sign-off. Methods and results: twenty histopathologists completed Stage 1 of the validation process and subsequently completed Stage 2 validation, prospectively reporting a total of 3777 cases covering eight specialities. All cases were initially viewed on digital whole slide images (WSI) with relevant parameters checked on glass slides, and discordances were reconciled before the case was signed out. Pathologists kept an electronic log of the cases, the preferred reporting modality used, and their experiences. At the end of each validation, a summary was compiled and reviewed with a mentor. This was submitted to the DP Steering Group who assessed the scope of cases and experience before sign-off for full validation. A total of 1.3% (49/3777) of the cases had a discordance between WSI and glass slides. A total of 61% (30/49) of the discordances were categorised as a minor error in a supplementary parameter without clinical impact. The most common reasons for diagnostic discordances across specialities included identification and grading of dysplasia, assessment of tumour invasion, identification of small prognostic or diagnostic objects, interpretation of immunohistochemistry/special stains, and mitotic count assessment. Pathologists showed similar mean diagnostic confidences (on Likert scale from 0 to 7) with a mean of 6.8 on digital and 6.9 on glass slide reporting. Conclusion: we describe one of the first real-world experiences of a department-wide effort to implement, validate, and roll out digital pathology reporting by applying the RCPath Recommendations for Implementing DP. We have shown a very low rate of discordance between WSI and glass slides.

Artificial Intelligence-Based Quality Assessment of Histopathology Whole-Slide Images within a Clinical Workflow: Assessment of ‘PathProfiler’ in a Diagnostic Pathology Setting

“…Furthermore, there is likely a degree of subjectivity as to what a pathologist would consider a 'suboptimal' WSI that will in part be specimen-dependent and reflective of the degree of scrutiny required for diagnosis. In our own practice, we noted a 2.6% rate of technical failure for digitised WSI during a study on the department-wide DP validation process, which was multifactorial but largely contributed to by focus issues [3]; however, this figure is from the early phases of DP implementation and may not reflect current practice. However, the figure of 2.7% of flagged WSI from non-resection cases in our study cohort would seem therefore to be in keeping with the expected number of suboptimal images in clinical practice, which is reassuring.…”

“…This study took place within a fully digitised Cellular Pathology laboratory which has accreditation for the use of DP under the United Kingdom Accreditation Service (UKAS) ISO:15189 (Medical Laboratory Accreditation-ISO 15189 (ukas.com, accessed on 30 April 2024), operating a digital pathology set up (Philips Image Management System, Philips Ultrafast Scanner version 3) since 2018, with full digitisation of our surgical pathology workload since 2020 [3,23]. The installed DP solution has no fully automated QC process and currently our QC pathway for WSI relies upon our time-pressured trained laboratory staff and is thus limited to a simple check of the scanned image for major issues flagged by the scanner and block-checking WSI prior to release of the image on the Information Management System (IMS) to the pathologist for diagnosis.…”

“…Quality of WSI of histopathology slides is recognised as a key factor in the acceptability of DP to Diagnostics 2024, 14, 990 2 of 17 practising histopathologists. Accurate diagnosis is reliant upon the histological features seen, and whilst there are recognised 'pitfalls' in digital diagnosis of which a pathologist must be aware [1][2][3], the WSI quality must not be inferior to glass slides (GS) for making clinical diagnoses.…”