Whole-Slide Imaging: The Future Is Here

In this issue of Veterinary Pathology, the first validation study on the diagnostic use of whole-slide imaging in veterinary pathology is available. While this first veterinary validation study of whole-slide imaging is fresh off the press, the technology is nothing new in our field. Over the years, veterinary pathology conferences have annually featured workshops addressing all aspects of digital imaging, covering subjects from digital imaging basics in the early 1990s to the employment of automated evaluation and analysis of biomarkers in digital slides in recent years. In 2007, the Department of Veterinary Pathology at the Armed Forces Institute of Pathology helped to introduce the technology of whole-slide imaging on a global basis within its Wednesday Slide Conference and Virtual Systemic Pathology Online (VSPO) programs (http://www.askjpc.org/vetpath), as an adjunct to the static images that had accompanied this material since 1994. In the late 2000s, veterinary schools around the world began exchanging student microscopes for digital slide scanners, incorporating whole slides into pathology and histology curricula, and facilitating both small group study as well as fiscal rewards. Today, whole-slide images are integral parts of all fields of veterinary pathology, including diagnosis, education, and research. Validation studies such as Bertram et al are critical not only for increased acceptance of the technology but also to continue the gains experienced in each of these diverse areas. These growing pains are not unique to our field. They have also been encountered in human pathology and have been overcome with a long series of validation studies, in research and diagnostic settings. A major milestone was recently achieved when the first digital pathology solution for primary diagnosis was approved by the Food and Drug Administration (FDA). The findings in this study closely parallel the early experience of commercial diagnostic laboratories that first deployed digital microscopy (DM) almost a decade ago. At that time, whole-slide imaging technology precluded efficient scanning at 400 ; 200 was used instead. Internal validation studies comparing quality of diagnosis based on DM vs light microscopy (LM) at 200 showed high concordance but, similar to the study reported here, were slightly diminished in the diagnosis of round cell tumors. During initial deployment, the willingness among pathologists to transition from LM to DM varied considerably. In general, the more LM experience that a pathologist had, the more reluctant he or she was to move away from the reliance on glass slides. Alternatively, younger pathologists tended to have a higher comfort level with digital technology, and the transition to DM was easier and more readily accepted. Today, improvements in whole-slide imaging technology allow efficient 400 scanning and have allowed commercial laboratories to transition anatomic pathology diagnosis completely to DM. The ability to distribute workload easily across the organization’s entire virtual workforce, regardless of geographic location, has improved turnaround time while simultaneously realizing cost savings from minimizing physical transport of glass slides. The digital connection also promotes simple realtime consultation between pathologists, improving the overall quality of the diagnostic service. Finally, as DM enables pathologists to work in virtual environments or at home, it provides the ability to recruit experienced diagnostic pathologists, provide greater work-life balance, and free up office space in the laboratory. As previously discussed, the operational efficiencies of scanned slides in education—the ability to share regional, emerging, or otherwise rare case material widely and efficiently—has proven to be extremely valuable in the education of pathologists of all levels of expertise. Today’s students, regardless of geographic location, are able to view scans of uniform content that may additionally be annotated for ease of review and interpretation. The use of databases that permit searching and sorting digital slides further facilitates their utility. Digital archiving of scans protects against potential breakage or loss of the corresponding glass slides. New educational applications mirror the improvement of whole-slide imaging technology and the decrease in storage expense—professional