Whole slide images as a platform for initial diagnostics in histopathology in a medium-sized routine laboratory

Whole slide imaging is the process of digitizing glass slides and the creation of Whole Slide Images (WSI), which enable the examination of pathology samples on a computer screen in a manner comparable to light microscopy. WSI have been used for different applications in pathology but their use for primary diagnostics is still limited. Implementing WSI for primary diagnostics would be a turning point necessitating extensive validation to unravel pitfalls and difficulties that could be encountered within the routine workflow. This article is aimed to describe the gradual integration of WSI into routine pathology diagnostics in a medium-sized routine pathology laboratory.

This project was started with optimizing the digital work environment including the setting up of validation studies, scanning preferences, storing WSI and the implemented adjustments to the workflow for the laboratory and the pathologist. Afterwards scanning glass slides was initiated in the department of pathology at the Atrium Medical Center, Heerlen, The Netherlands, for performing primary diagnostics of breast biopsies. Later this was extended to other specimen types including resections.

The validation studies yielded a high concordance rate between WSI and conventional diagnoses. Routine primary WSI based diagnosis was possible in 82.1% of cases. Failure of digital diagnosis was mainly related to poor image quality and logistic problems.

The quality of the currently produced WSI is sufficient for primary diagnostics in 82.1% of the cases. Improving image quality, adequate retrieval and controlling scanning error will definitely encourage the wide adaptation in routine diagnostics.