Digital Image Virtual Microscopy: Experiences at the NTP with Peer Review and PWGs
Rapid technical advances in the quality of digital scanning of glass microscope slides, image processing and digital storage, combined with high speed networking and improved personal computers, is making remote evaluation of digitally imaged tissue sections an increasingly viable option in histopathology evaluation. It is relatively easy to scan whole tissues on microscopic slides and store vast amounts of image information and metadata efficiently. In 1997, the National Toxicology Program (NTP) staff began the transition from film based technology to digital based technology to capture images of lesions in tissue sections. In 2002, the NTP started using whole slide scanning technology. NTP’s digital images have been used for production of training materials, to aid efforts in standardizing NTP nomenclature and to support international harmonization efforts. Digital images have also been used to illustrate lesions during NTP Pathology Working Groups (PWGs), poster presentations at meetings, in journal publications, at workshops, and for use in monograph (supplement) publications.
Recently, the NTP evaluated the use of digital imaging technology during peer review and PWG reviews. Digital image evaluation can enhance the PWG process either as a complement to the microscopic slide examination or as a possible replacement for direct microscopic examination of slides. The potential benefits include availability of scanned digital images for review prior to the PWG; quick and accurate demonstration of key lesions to all PWG participants; and participation and voting by experts and other participants unable to travel to the PWG. The main drawbacks include technical limitations of the hardware and software which sometimes results in prolonged waiting times for images to appear; and inability to control depth of field or to evaluate features such as subtle color variation (e.g., hepatocellular foci) and intracellular changes (e.g., renal hyaline droplet accumulation). In conclusion, the results of these investigations suggest that digital reviews may be a useful, productive stage in the PWG process. However, the use of this technology in the PWG or peer review process should be limited, specific and should always be supported by thorough evaluation of the glass slides.
Source: EPL, Inc.
