Leading article Digital pathology services in acute surgical situations D. A. H. Neil 1 and A. J. Demetris 2 1 Department of Cellular Pathology, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham B15 2WB, UK, and 2 Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA (e-mail: desley.neil@uhb.nhs.uk) Published online 11 June 2014 in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.9576 The management of some acute surgical situations requires rapid microscopic tissue assessment to determine the nature of mass lesions and/or potential organ donor suitabil- ity for transplantation 1 . A substantial proportion of this work occurs either outside routine hours or without ready availability of specialized exper- tise. This requires an emergency or on-call anatomical pathology service, the staffng of which varies by hos- pital, region and country. Countries with a fee-for-service approach, such as the USA, use pathologist on-call schedules routinely prepared weeks in advance. Countries with a national or regional health service budget, such as the UK, however, do not rou- tinely have on-call pathology services, although there is variation between individual hospitals. Where on-call services are available, all hospital pathologists participate, in theory, in the on-call rotation, with some countries (for example the USA) having initial assessment by trainees or junior staff and ‘back-up’ expertise available when required. As pathologists and hospitals become increasingly subspecialized, how- ever, deskilling in specialist areas is inevitable. Service reorganizations affecting paediatrics, women’s health, cancer or organ-specifc services demand an evolution to a rotation of subspecialist pathologists who might be located at different centres versus a ‘generalist’ on-call rotation involving individuals at a specifc hospital. This produces issues related to distance between the specialist pathologist and the specimen, for which digital pathology provides the solution. Digital pathology is the creation of digital image fles that can be transmitted over the internet via a variety of formats, a concept similar to the worldwide radiology standard, Picture Archiving and Communica- tion System (PACS), which enables digital images to be viewed on remote computer monitors. A rapid, simple and cheap form of digital pathology simply requires a microscope equipped with a live camera feed connected to a mon- itor. A remote expert pathologist who has internet access can share the microscope view using secure desktop sharing software. The remote viewer, however, is reliant on the on-site person controlling the micro- scope and, for this method to work, a pathologist is usually required on site, making the system more restrictive and resource-expensive. This can be overcome by using a microscope with a robotic stage and appropriate soft- ware, so that the remote pathologist can control the microscope, although panning and changing magnifcation is time-consuming. Alternatively, whole slide images (WSIs) can be created by digi- tally scanning an entire glass slide. This requires a digital slide scanner, which is essentially a microscope and software-driven robotic stage that methodically moves the slide in the x and y axes under the microscopic lens while simultaneously optimizing the Z-plane focus and photographing each microscopic feld. Approximate scan times for biopsies depend on the scan- ning objective lens (40 × takes longer), but averages 1–5 min. The software then ‘stitches’ together the individual images, recreating a digital copy of the original slide. This virtual slide, or WSI, can then be either stored on a local server connected to the scanner or transmitted for viewing. The image quality of early scanners was inferior to that of conventional microscopes, but the optical resolu- tion (approximately 0⋅14 μm/pixel) of current-generation scanners approaches that of the conventional microscope, enabling excellent accu- racy correlation 2,3 . Consequently, regulatory agencies in some countries have certifed their use for routine diagnosis 4 . Although currently not available, a universal format of image storage and transfer, DICOM (Digital Imaging and COmmunications in Medicine) 5,6 , the international stan- dard used in PACS, is being developed to ensure compatibility of WSIs from different vendors. Secure pathways already in place for the transfer of radiology images can be adapted for pathology images. For magnifcation standardization, WSI resolution is measured in microns per pixel, rather than the objective lens magnifcation used for the scan 7 (lower micron/pixel indicates higher resolution). Proper slide preparation is impor- tant for acceptable digital image quality. Specimen artefacts and incon- sistent tissue thickness can result in suboptimal WSIs. As with glass slides, the pathologist’s assessment of the WSI is important to ensure diagnostic quality and, if judged inadequate, a new section or a repeat scan can be requested. © 2014 BJS Society Ltd BJS 2014; 101: 1185–1186 Published by John Wiley & Sons Ltd Downloaded from https://academic.oup.com/bjs/article/101/10/1185/6138042 by guest on 13 August 2022