Implementation of large-scale routine diagnostics using whole slide imaging in Sweden: Digital pathology experiences 2006-2013

TLDR

Recent advances in whole‑slide imaging scanner quality and storage cost reductions have made routine digital pathology feasible. This study reports experiences from two Swedish sites that deployed large‑scale WSI for primary review and surveys pathologists on their use of digital slides. Digitization began in 2006 to improve ergonomics, with all slides scanned and optionally reviewed on screen or microscope, remote case reporting and outsourcing of ~150 weekly cases, and a web questionnaire used to assess pathologist workflow choices. Over 500,000 slides were scanned since 2008, 38 ± 28 % of cases were diagnosed digitally, pathologists reported improved ergonomics and sufficient image quality, yet they frequently switch between digital and conventional microscopy,.

Abstract

Recent technological advances have improved the whole slide imaging (WSI) scanner quality and reduced the cost of storage, thereby enabling the deployment of digital pathology for routine diagnostics. In this paper we present the experiences from two Swedish sites having deployed routine large-scale WSI for primary review. At Kalmar County Hospital, the digitization process started in 2006 to reduce the time spent at the microscope in order to improve the ergonomics. Since 2008, more than 500,000 glass slides have been scanned in the routine operations of Kalmar and the neighboring Linköping University Hospital. All glass slides are digitally scanned yet they are also physically delivered to the consulting pathologist who can choose to review the slides on screen, in the microscope, or both. The digital operations include regular remote case reporting by a few hospital pathologists, as well as around 150 cases per week where primary review is outsourced to a private clinic. To investigate how the pathologists choose to use the digital slides, a web-based questionnaire was designed and sent out to the pathologists in Kalmar and Linköping. The responses showed that almost all pathologists think that ergonomics have improved and that image quality was sufficient for most histopathologic diagnostic work. 38 ± 28% of the cases were diagnosed digitally, but the survey also revealed that the pathologists commonly switch back and forth between digital and conventional microscopy within the same case. The fact that two full-scale digital systems have been implemented and that a large portion of the primary reporting is voluntarily performed digitally shows that large-scale digitization is possible today.