Aims Digital pathology offers the potential for significant benefits in diagnostic pathology, but currently the efficiency of slide viewing is a barrier to adoption. We hypothesised that presenting digital slides for simultaneous viewing of multiple sections of tissue for comparison, as in those with immunohistochemical panels, would allow pathologists to review cases more quickly. Methods Novel software was developed to view synchronised parallel tissue sections on a digital pathology workstation. Sixteen histopathologists reviewed three liver biopsy cases including an immunohistochemical panel using the digital microscope, and three different liver biopsy cases including an immunohistochemical panel using the light microscope. The order of cases and interface was fully counterbalanced. Time to diagnosis was recorded and mean times are presented as data approximated to a normalised distribution. Results Mean time to diagnosis was 4 min 3 s using the digital microscope and 5 min 24 s using the light microscope, saving 1 min 21 s (95% CI 16 s to 2 min 26 s; p=0.02), using the digital microscope. Overall normalised mean time to diagnosis was 85% on the digital pathology workstation compared with 115% on the microscope, a relative reduction of 26%. Conclusions With appropriate interface design, it is quicker to review immunohistochemical slides using a digital microscope than the conventional light microscope, without incurring any major diagnostic errors. As digital pathology becomes more integrated with routine clinical workflow and pathologists increase their experience of the technology, it is anticipated that other tasks will also become more time-efficient.

This article describes the design and evaluation of two generations of an interface for navigating datasets of gigapixel images that pathologists use to diagnose cancer. The interface design is innovative because users panned with an overview:detail view scale difference that was up to 57 times larger than established guidelines, and 1 million pixel “thumbnail” overviews that leveraged the real estate of high-resolution workstation displays. The research involved experts performing real work (pathologists diagnosing cancer), using datasets that were up to 3,150 times larger than those used in previous studies that involved navigating images. The evaluation provides evidence about the effectiveness of the interfaces and characterizes how experts navigate gigapixel images when performing real work. Similar interfaces could be adopted in applications that use other types of high-resolution images (e.g., remote sensing or high-throughput microscopy).

We thank Rojo and Bueno for their thoughtful commentary on our study of the effect of display resolution on diagnostic speed. Display resolution is a critical factor in digital pathology efficiency. Our design decisions are described in detail elsewhere,[1,2] but were deliberately based on what is known about microscopy (the space-bandwidth product of a typical diagnostic microscope is 5–50 megapixels, and the angular field of view is approximately 50–70°) and human physiology (the angular resolution of the eye is approximately 0.5–1 arc-minute per pixel at the fovea). The three screen system in this work was designed to mimic these parameters as closely as possible with the displays available to us at the time. Rojo and Bueno raise the question of whether the particular NVIDIA Quadro graphics cards used would enable optimal performance but do not state what they mean by “optimal.” In our view, the most important factor is that a graphics card is capable of driving the displays at their native resolution and refresh rate, and this was the case for the graphics card/displays combination used in our study. The maximum refresh rates quoted for both displays are for analog inputs. In our study, we used digital inputs for both displays. In both cases, the maximum refresh rate is 60 Hz for digital inputs. NVIDIA Quadro graphics cards are designed with GPU intensive three-dimensional CAD-type applications in mind and are not stressed by two-dimensional applications such as ours. One must be careful when comparing the contrast ratio of different displays. There is no industry standard test for measuring contrast ratios of displays and the figures are often manipulated for marketing purposes and may not be directly comparable. The environment in which the display is located can also affect the contrast ratio. The input images used eight bits per channel (16.7 million colors), so no advantage would have been gained of the extra colors available on the Dell display. Rojo and Bueno also raise the question of the level of experience of the pathologists who participated in the study. Experience is an important issue, and unfortunately we do not have access to data regarding our participants’ years of experience. However, the use of a crossover design, with all participants reviewing slides in each condition, protects against the variation in participants’ level of experience introducing bias. Rojo and Bueno reflect on the increasing popularity of high-resolution displays in digital pathology. In our most recent work,[2] we combined two high-resolution medical grade screens, a Barco 6.7 megapixel Coronis Fusion and a 3.1 megapixel Nio screen, to provide an almost 10 megapixel display [Figure 1]. The slide is viewed in detail on the 6.7 megapixel screen, although the 3.1 megapixel screen provides an overview of the slide currently being viewed as well as an overview of all slides in the case. This removed any problems caused by bezels or users focusing on the central screen. Using this set up, combined with a unique design that enables real-time rendering of slides, although providing a quick and intuitive means of navigation via the slide overviews, we were able to show no significant difference in time to diagnosis between digital and glass slides. Figure 1 The Leeds virtual microscope Finally, we would like to clarify a point about our methodology. All participants reviewed the same slides, with the slide set used in each condition counterbalanced. This means that, while there were 81 trials, only nine slides were used, not 81. Financial Support and Sponsorship The work described here is independent research commissioned by the National Institute for Health Research (NIHR) under the New and Emerging Applications of Technology (NEAT) programme. The authors acknowledge the support of the NIHR, through the Comprehensive Clinical Research Network. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Conflicts of Interest There are no conflicts of interest.

Performing diagnoses using virtual slides can take pathologists significantly longer than with glass slides, presenting a significant barrier to the use of virtual slides in routine practice. Given the benefits in pathology workflow efficiency and safety that virtual slides promise, it is important to understand reasons for this difference and identify opportunities for improvement. The effect of display resolution on time to diagnosis with virtual slides has not previously been explored. The aim of this study was to assess the effect of display resolution on time to diagnosis with virtual slides. Nine pathologists participated in a counterbalanced crossover study, viewing axillary lymph node slides on a microscope, a 23-in 2.3-megapixel single-screen display and a three-screen 11-megapixel display consisting of three 27-in displays. Time to diagnosis and time to first target were faster on the microscope than on the single and three-screen displays. There was no significant difference between the microscope and the three-screen display in time to first target, while the time taken on the single-screen display was significantly higher than that on the microscope. The results suggest that a digital pathology workstation with an increased number of pixels may make it easier to identify where cancer is located in the initial slide overview, enabling quick location of diagnostically relevant regions of interest. However, when a comprehensive, detailed search of a slide has to be made, increased resolution may not offer any additional benefit.

Digital pathology promises a number of benefits in efficiency in surgical pathology, yet the longer time required to review a virtual slide than a glass slide currently represents a significant barrier to the routine use of digital pathology. We aimed to create a novel workstation that enables pathologists to view a case as quickly as on the conventional microscope. The Leeds Virtual Microscope (LVM) was evaluated using a mixed factorial experimental design. Twelve consultant pathologists took part, each viewing one long cancer case (12-25 slides) on the LVM and one on a conventional microscope. Total time taken and diagnostic confidence were similar for the microscope and LVM, as was the mean slide viewing time. On the LVM, participants spent a significantly greater proportion of the total task time viewing slides and revisited slides more often. The unique design of the LVM, enabling real-time rendering of virtual slides while providing users with a quick and intuitive way to navigate within and between slides, makes use of digital pathology in routine practice a realistic possibility. With further practice with the system, diagnostic efficiency on the LVM is likely to increase yet more.

Aims: To create and evaluate a virtual reality (VR) microscope that is as efficient as the conventional microscope, seeking to support the introduction of digital slides into routine practice.Methods and results: A VR microscope was designed and implemented by combining ultra‐high‐resolution displays with VR technology, techniques for fast interaction, and high usability. It was evaluated using a mixed factorial experimental design with technology and task as within‐participant variables and grade of histopathologist as a between‐participant variable. Time to diagnosis was similar for the conventional and VR microscopes. However, there was a significant difference in the mean magnification used between the two technologies, with participants working at a higher level of magnification on the VR microscope.Conclusions: The results suggest that, with the right technology, efficient use of digital pathology for routine practice is a realistic possibility. Further work is required to explore what magnification is required on the VR microscope for histopathologists to identify diagnostic features, and the effect on this of the digital slide production process.

Large, high-resolution displays allow orders of magnitude more data to be visualized at a time than ordinary computer displays. Previous research is inconclusive about the circumstances under which large, high-resolution displays are beneficial and lacks behavioural data to explain inconsistencies in the findings. We conducted an experiment in which participants searched maps for densely or sparsely distributed targets, using 2-million-pixel (0.4 m × 0.3 m), 12-million-pixel (1.3 m × 0.7 m) and 54-million-pixel (3.0 m × 1.3 m) displays. Display resolution did not affect the speed at which dense targets were found, but participants found sparse targets in easily identifiable regions of interest 30% faster with the 54-million-pixel display than with the other displays. This was because of the speed advantage conferred by physical navigation and the fact that the whole dataset fitted onto the 54-million-pixel display. Contrary to expectations, participants found targets at a similar speed and interacted in a similar manner (mostly short panning movements) with the 2- and 12-million-pixel displays even though the latter provided more opportunity for physical navigation, though this may have been because panning used velocity-based control. We are applying these findings to the design of a virtual microscope for the diagnosis of diseases such as cancer.

Histopathologists diagnose cancer and other diseases by using a microscope to examine glass slides containing thin sections of human tissue. Technological advances mean that it is now possible to digitise the slides so that they can be viewed on a computer, promising a number of benefits in terms of both efficiency and safety. Despite this, uptake of digital microscopy for diagnostic work has been slow, and research suggests scepticism and uncertainty amongst histopathologists. In order to design a successful digital microscope, one which fits with the work practices of histopathologists and which they are happy to use within their daily work, we have undertaken a workplace study of a histopathology department. In this paper, we present the findings of that study and discuss the implications of these findings for the design of a digital microscope. The findings emphasise the way in which a diagnosis is built up as particular features on the glass slides are noticed and highlighted and the various information sources that are drawn on in the process of making a diagnosis.

The Leeds Virtual Microscope is an interactive visualization system, capable of rendering gigapixel virtual slides onto high-resolution, wall-sized displays. We describe the evaluation of this technology for teaching pathology to undergraduate medical students, providing insights into the use of high-resolution, wall-sized displays in an educational context. Students were quickly able to become confident in using the technology, collaboratively exploring virtual slides in order to understand the mechanisms of disease. Being able to point with a finger to features on virtual slides promoted multi-way interaction between the students and tutor, led to the spontaneous expansion of the tutorial's scope, and was indicative of a high level of engagement. Students were very positive about being able to interact with the virtual slides and described their increased enthusiasm for pathology as a subject.

Aims: To study the current work practice of histopathologists to inform the design of digital microscopy systems.Methods and results: Four gastrointestinal histopathologists were video-recorded as they undertook their routine work. Analysis of the video data shows a range of activities beyond viewing slides involved in reporting a case. There is much overlapping of activities, supported by the 'eyes free' nature of the pathologists' interaction with the microscope. The order and timing of activities varies according to consultant.Conclusions: In order to support the work of pathologists adequately, digital microscopy systems need to provide support for a range of activities beyond viewing slides. Digital microscopy systems should support multitasking, while also providing flexibility so that pathologists can adapt their use of the technology to their own working patterns.

The use of Virtual Environments has been widely reported as a method of teaching anatomy. Generally such environments only convey the shape of the anatomy to the student. We present the Bangor Augmented Reality Education Tool for Anatomy (BARETA), a system that combines Augmented Reality (AR) technology with models produced using Rapid Prototyping (RP) technology, to provide the student with stimulation for touch as well as sight. The principal aims of this work were to provide an interface more intuitive than a mouse and keyboard, and to evaluate such a system as a viable supplement to traditional cadaver based education.