Digital Whole Slide Imaging Compared With Light Microscopy for Primary Diagnosis in Surgical Pathology

Abstract

Context.— The adoption of digital capture of pathology slides as whole slide images (WSI) for educational and research applications has proven utility. Objective.— To compare pathologists' primary diagnoses derived from WSI versus the standard microscope. Because WSIs differ in format and method of observation compared with the current standard glass slide microscopy, this study is critical to potential clinical adoption of digital pathology. Design.— The study enrolled a total of 2045 cases enriched for more difficult diagnostic categories and represented as 5849 slides were curated and provided for diagnosis by a team of 19 reading pathologists separately as WSI or as glass slides viewed by light microscope. Cases were reviewed by each pathologist in both modalities in randomized order with a minimum 31-day washout between modality reads for each case. Each diagnosis was compared with the original clinical reference diagnosis by an independent central adjudication review. Results.— The overall major discrepancy rates were 3.64% for WSI review and 3.20% for manual slide review diagnosis methods, a difference of 0.44% (95% CI, −0.15 to 1.03). The time to review a case averaged 5.20 minutes for WSI and 4.95 minutes for glass slides. There was no specific subset of diagnostic category that showed higher rates of modality-specific discrepancy, though some categories showed greater discrepancy than others in both modalities. Conclusions.— WSIs are noninferior to traditional glass slides for primary diagnosis in anatomic pathology.

Validation of a digital pathology system including remote review during the COVID-19 pandemic

“…A Q-probe study performed by the College of American Pathologists analyzed self-reported laboratory discrepancy frequencies by prospective secondary review of glass slides to be a median of 5.1%, for anatomic pathology [33]. In addition, as previously published and accepted by the Food and Drug Administration in two other studies, the major discordance rate compared to a reference diagnosis was 4.9% for whole slide images and 4.6% using glass slides in one study [2]; and 3.6% for whole slide images and 3.2% for glass slides in another study [1]. In our study, the reference standard was designated as conventional light microscopy.…”

“…At MSK, whole slide scanners from multiple vendors and custom viewer software haven been implemented and validated to support clinical workflow. The aims of this study include: (1) to assess operational feasibility supporting remote review and primary reporting of pathology specimens using digital pathology systems; (2) to evaluate remote access performance and usability for pathologist remote signout; (3) to validate a digital pathology system for remote primary diagnostic use.…”

Digital Pathology During the COVID-19 Outbreak in Italy: Survey Study (Preprint)

“…Moreover, recent studies have consistently reported high, intermediate, and low discordant rates for bladder, breast, and gastrointestinal tract specimens, respectively [41,42]-a finding suggesting intrinsic difficulties of specific areas. In contrast, we observed 4%, 8%, and 12% of discrepancies for urology, gastrointestinal tract, and breast specimens.…”

“…A more recent review, covering studies published until 2018, reported a disagreement ranging from 1.7% to 13% [10]. Two multicentric, randomized, non-inferiority studies reported major discordant rates of 4.9% [41] and 3.6% [42] between diagnoses done by digital and glass slides. Furthermore, a study from a single, large academic center reported an overall diagnostic equivalency of 99.3% [43].…”

Rapid Validation of Telepathology by an Academic Neuropathology Practice During the COVID-19 Pandemic

“…32 Several published studies have reported low major and minor discrepancy rates, demonstrating that diagnoses rendered by WSI are not inferior to primary diagnoses via traditional histopathology. [33][34][35][36][37][38][39][40][41][42][43][44][45] Per the College of American Pathologists (CAP; GEN.52920), each laboratory must validate WSS/WSI platforms for each clinical diagnostic usage by performing its own validation study. 46 Owing to the COVID-19 pandemic, CAP initiated advocacy efforts geared toward a temporary waiver of current regulations limiting remote review of pathology slides in sites physically outside of the Clinical Laboratory Improvement Amendments (CLIA)-accredited laboratory as set by the Centers for Medicare & Medicaid Services (CMS) and the Department of Health and Human Services.…”