Posters. P3 North west non‐gynaecological cytology EQA pilot CD ROM scheme 2002–2003

The 8th circulation of this scheme was preceded by a CD ROM circulation of selected digital images and presented as individual JPEG file images in a single folder on the CD ROM. The number of images per case ranged from three to eight. The delegates will have an opportunity to assess these themselves prior to uncovering the consensus diagnosis provided by the participants. Of the 76, 29 participants of the scheme provided a completed answer sheet for the image‐based circulation. To date, 19 have now also supplied answers on the actual slide circulation. The same diagnosis on image and slide circulation varied from 5/19 to 19/19 with a mode of 14/19. The case that provided the poorest correlation was because of a generalized undercall of suspicious in a case which achieved almost complete consensus on the slide circulation. It had been the most difficult to photograph. The case that provided the next poorest correlation 11/19 was the case that had the poorest consensus diagnosis on the slide circulation. The two cases that provided the best correlation 18/19 and 19/19 were two cases that provided 100% consensus diagnosis on the slide‐based circulation. Comments were received from 20 participants about the image circulation ranging from ‘great’ to ‘awful’ with the majority of 12 participants not happy for their diagnostic capability to be assessed on such images alone. Two stated that the CD was easier to use on their home computer than their NHS one. In conclusion an image circulation overcomes many of the inherent problems with a slide circulation for EQA purposes and can provide an overall 70% correlation with a slide circulation but a significant number of pathologists do not find this an acceptable method for EQA.     

COST Action “EuroTelepath”: digital pathology integration in electronic health record,including primary care centres

INTRODUCTION: Digital pathology includes the information technology that allows for the management of information, including data and images, generated in an anatomic pathology department. COST ACTION IC0604: The integration of digital slides in the electronic health record is one of the main objectives of COST Action IC0604 "Telepathology Network in Europe" (EURO-TELEPATH). Fostering use of medical informatics standards and adapting them to current needs is needed to manage efficiently extremely large medical images, like digital slide files. DIGITAL SLIDES IN PATHOLOGY: Digital slides can play a role in disease prevention, primary diagnosis, and second opinion. In all these tasks, automated image analysis can also be a most valuable tool. INTEROPERABILITY IN PATHOLOGY INFORMATION SYSTEMS: In order to achieve an efficient interoperability between pathology information systems with other clinical information systems, obtaining a seamless integration of pathology images (gross pictures and digital slides) with LIS-Pathology Information system in a web environment is an important task. Primary care information systems should also be included in the integration, since primary care centres play an essential role in the generation of clinical information and specimen collection. A common terminology, based in SNOMED CT is also needed. CONCLUSIONS: Main barrier in the integration of digital slides in pathology workflow and eHealth record is the cost of current digital slide scanners. Pathology information system vendors should participate in standardization bodies.     

Accuracy and perceptions of virtual microscopy compared with glass slide microscopy in cervical cytology

A. Evered and N. Dudding Accuracy and perceptions of virtual microscopy compared with glass slide microscopy in cervical cytology Objective: To evaluate virtual microscopy in terms of diagnostic performance and acceptability among practising cytologists. Methods: Twenty‐four experienced cytologists were recruited to examine 20 SurePath® cervical cytology slides by virtual microscopy. Diagnostic accuracy was compared with glass slide microscopy using an unbiased crossover experimental design. Responses were allocated a score of one for a correct identification of normal or abnormal (borderline/atypical changes in squamous or glandular cells or worse) and a score of zero for an incorrect response (a normal slide reported as abnormal or vice versa). Perceptions of virtual microscopy were assessed by questionnaire analysis. Results: Participants yielded a total of 285 responses for the virtual slide set and 300 for the glass slide set. The approximate time to screen a virtual slide was 18 minutes, compared with 8 minutes or less for a glass slide. Overall there was no significant difference between virtual microscopy and glass slide microscopy in terms of diagnostic accuracy (P = 0.22). Virtual microscopy under‐performed when images were captured over a narrow focal range (P = 0.01). Diagnostic accuracy of virtual microscopy equalled that of glass slide microscopy when participants were able to focus through the full thickness of the slide images (P = 0.07). The most common difficulties experienced by participants with virtual microscopy were freezing of the computer screen during image download, slow response of the computer during slide movement and, in some instances, ‘fuzzy’ images. Cytologists have a strong preference for glass slides over virtual microscopy despite the overall equal diagnostic performance of the two viewing modalities. Conclusions: Diagnostic accuracy of virtual microscopy can equal that of glass slide microscopy. However, without good computer network connections, wide focal range and software that permits effortless navigation across virtual slides, cytologists are unlikely to be convinced of the utility of this technology for cytology screening and diagnosis.     

An update on the validation of whole slide imaging systems following FDA approval of a system for a routine pathology diagnostic service in the United States

Pathologists have used light microscopes and glass slides to interpret the histologic appearance of normal and diseased tissues for more than 150 years. The quality of both microtomes used to cut tissue sections and microscopes has improved significantly during the past few decades, but the process of rendering diagnoses has changed little. By contrast, major advances in digital technology have occurred since the introduction of hand held electronic devices, including the development of whole slide imaging (WSI) systems with software packages that can convert microscope images into virtual (digital) slides that can be viewed on computer monitors and via the internet. To date, however, these technological developments have had minimal impact on the way pathologists perform their daily work, with the exception of using computers to access electronic medical records and scholarly web sites for pertinent information to assist interpretation of cases. Traditional practice is likely to change significantly during the next decade, especially since the Federal Drug Administration in the USA has approved the first WSI system for routine diagnostic practice. I review here the development and slow acceptance of WSI by pathology departments. I focus on recent advances in validation of WSI systems that is required for routine diagnostic reporting of pathology cases using this technology.     

The effect of reducing the number of cells scored on the performance of the in vivo rat liver UDS assay

The most labour-intensive feature of the in vivo rat liver UDS assay is the scoring of hepatocyte autoradiograms by microscope. Even with image analyser and computer equipment the scoring phase of a full study might require half of the technical effort applied. Practice recommended by guidelines has been to score 50 cells/slide and two slides per animal. Now sufficient data have been accumulated, an evaluation was made to observe whether this procedure was necessary. An analysis of the accumulated UDS database in our laboratory was made to determine the sources of variability of mean net nuclear grain count, [N - C]. It was observed that the two largest components of variation in negative control animal mean [N - C]. were between-day and interanimal variability. The contribution from sampling error during slide scoring was relatively small. Theoretical calculations showed that the greater sampling error derived from scoring 30 rather than 50 cells/slide would result in only a marginal increase in total assay variation. To test this, 30 cells/slide were randomly selected from the 50 cells scored originally in negative control animals in each of 18 studies over an 18-month period. It was confirmed that reducing the number of cells had a negligible effect on the variation of negative control animal mean [N - C] values. Furthermore, analysis of data from 10 more studies confirmed that within-study variation would be essentially unaffected by scoring 30 cells/slide. The use of 30 rather than 50 cells per slide (a total of 60 cells per animal) has therefore been adopted for all current studies and scoring procedures modified to avoid operator bias during the selection of a smaller number of cells.     

Whole slide images and digital media in pathology education, testing, and practice: the Oklahoma experience

Examination of glass slides is of paramount importance in pathology training. Until the introduction of digitized whole slide images that could be accessed through computer networks, the sharing of pathology slides was a major logistic issue in pathology education and practice. With the help of whole slide images, our department has developed several online pathology education websites. Based on a modular architecture, this program provides online access to whole slide images, still images, case studies, quizzes and didactic text at different levels. Together with traditional lectures and hands-on experiences, it forms the back bone of our histology and pathology education system for residents and medical students. The use of digitized whole slide images has a.lso greatly improved the communication between clinicians and pathologist in our institute.     

Telecytologic diagnosis of breast fine needle aspiration biopsies. Intraobserver concordance

OBJECTIVE: To determine the intraobserver concordance between telecytologic and glass slide diagnosis of breast fine needle aspirates. STUDY DESIGN: Twenty-five cases, originally received in consultation, were each examined by three cytopathologists. An average of seven compressed digital images per case were presented, together with a brief clinical history, using the http protocol and an internet browser. RESULTS: Agreement between the telecytologic and glass slide diagnosis ranged from 80% to 96%. Nevertheless, two cases that had been unequivocally diagnosed as malignant based upon video images were considered to be benign by the same pathologist when reviewing the glass slides. Both diagnostic confidence and self-concordance were higher for one pathologist having significant previous video microscopy experience. CONCLUSION: Although intraobserver concordance between telecytologic and glass slide diagnoses of breast fine needle aspirates is high, refinement of existing criteria for diagnosis of malignancy, taking account of the particular limitations associated with telecytologic diagnosis, may be prudent prior to widespread use of telecytology for fine needle aspiration evaluation.     

The Yorkshire slide exchange external quality assessment (EQA) scheme

A slide circulation scheme measuring cervical screening performance of individual cytologists in 15 laboratories in Yorkshire Regional Health Authority is described. The advantages and disadvantages are compared with the current National Proficiency Testing (NPT) scheme. The results indicate that a slide circulation scheme can be successfully used in cervical cytology external quality assessment (EQA). Levels of participation are better than those currently achieved by regional variations of the NPT scheme, and the use of laboratory consensus in the selection of scoring slides appears to be no less valid than the use of a pre‐selected slide pool assembled by an expert panel. The volume of data accumulated in one round is considerably greater than that achieved by proficiency testing and the educational value is regarded as high. However, the scheme is very time consuming for participants and consequently expensive for laboratories. The lack of external supervision increases the risk of unfair practices within individual laboratories. Because of these problems, Yorkshire has now switched to an NPT scheme.     

Toward implementation of a regional quality assurance program in cytopathology: the Hong Kong experience

OBJECTIVE: To develop a local quality assurance program in cytopathology based on circulation of patient specimens on glass slides, with limited resources. STUDY DESIGN: A working group was set up for design and running of the program. Participation is on a laboratory basis. The scope and frequency of testing are defined. Well-documented cases (including gynecologic, nongynecologic and fine needle aspiration cytology) with commonly encountered diagnoses are collected. Consensus concerning the diagnosis, interpretive menu and scoring system is sought before the actual slide circulations using express mail. After returning their answers to the program organizer, the participating laboratories receive immediate feedback on their scores, with reference answers, explanatory notes, "whole-mount" images of glass slides and cumulative responses of peer laboratories for on-site checking. At the end of each year, an electronic file containing representative photomicrographs of all cases examined is provided to individual laboratories for their permanent records and training purposes. RESULTS: The program was launched in mid-2003. There were 24 and 27 participating laboratories from Hong Kong (and Macau) in 2003 and 2004, respectively. To date, >150 well-documented cytology cases are available in the slide pool and ready for circulation. As the revenue is mainly to cover the expenses of express mail, the program can be carried out at a relatively low cost. CONCLUSION: In order to have any cytology quality assurance program accepted by local laboratories, it has to be fair and practical. Strict confidentiality needs to be observed throughout the process. This program emphasizes both performance assessment and educational value. Adequate representation from experienced local cytology workers, detailed documentation support from authorities and assistance from dedicated staff are essential to the success of any external proficiency testing scheme. Regular review and evaluation are also necessary for continuous improvement. The Hong Kong experience can serve as an example of running a glass slide-based cytology quality assurance program in a small region with limited resources.     

Inadequate cervical smears: results of an educational slide exchange scheme

Fifty-six slides, predominantly inadequate and of varying difficulty, were circulated to 12 laboratories as an educationally based slide exchange scheme. Three slides failed to achieve an agreed majority consensus opinion. Seventy percent of participants agreed with the consensus opinion in 80% of slides. Of the slides originally reported as inadequate, the consensus diagnosis was inadequate in 78%, negative in 12% and abnormal in 10%. The latter included two cases of high-grade dyskaryosis. There was good agreement for the two most frequent causes of inadequacy in submitted slides (obscured and poor cellularity). There was poor consistency in reporting the presence or absence of endocervical and immature squamous metaplastic cells, to an extent that questions their use in the assessment of smear adequacy. Three inadequate slides on consensus opinion were associated with subsequent cervical intraepithelial neoplasia (grade III) or invasive squamous cell carcinoma. In the latter case, the slide had originally been reported as negative by the submitting laboratory.     

An abbreviated method for the quality control of pollen counters

We present an abbreviated method for conducting large scale quality control (QC) exercises over limited time periods, which was used for examining the proficiency of technicians involved in the electronic Pollen Information Network (ePIN). The goal was for technicians to have their analysis skills evaluated at least twice: (1) by having at least one of their slides successfully checked by other counters in the ePIN network and (2) by successfully examining at least one additional slide from other sites. Success was judged as a relative difference (RDif %) ≤ 30% between the two daily average pollen concentrations. A total of 21 sites participated in the ePIN QC exercise. All of the results for total pollen had RDif % < 30%. Only five results had RDif > 30%, three for Betula and two for Poaceae pollen. Of these, three were slides containing < 40 pollen/m³ daily average and two were for sites that had microscopes with small fields of view and examined < 10% of the slide surface. More than 80% of the participants had at least two slides successfully checked by someone else in the network, and all of the participants had one slide successfully examined. The latter is comparable to a traditional ring test where only one slide is sent to participating sites. The method described here enabled a large number of technicians to be examined in a short period of time and represents a viable alternative to other approaches that can take many months to complete.     

Proficiency testing in cytology laboratories in Ontario, Canada: a decade of experience. II. Results of initial surveys

The results of the initial surveys in the cytology proficiency testing of the medical laboratories in the Province of Ontario, Canada, showed a high correlation between the opinions of the testing committee and the participants in the categories of "no abnormal cells," "metaplasia" and forms of "benign atypia." The proportion of times that slides were tested in the categories of dysplasia and malignancy in the surveys increased from 38% by the end of survey 3 to 46% by the end of survey 5. A progressive improvement in the diagnostic accuracy was demonstrated in the categories of malignancy and severe dysplasia while results were more variable in the categories of moderate and mild dysplasia. Several educational activities were initiated following survey 3, including development and circulation of demonstration sets of marked glass slides for repeated circulation to participants as well as copies of a slide/tape presentation describing the program and specific case material.     

Five years of experience teaching pathology to dental students using the WebMicroscope

Background

We describe development and evaluation of the user-friendly web based virtual microscopy - WebMicroscope for teaching and learning dental students basic and oral pathology. Traditional students microscopes were replaced by computer workstations.

Methods

The transition of the basic and oral pathology courses from light to virtual microscopy has been completed gradually over a five-year period. A pilot study was conducted in academic year 2005/2006 to estimate the feasibility of integrating virtual microscopy into a traditional light microscopy-based pathology course. The entire training set of glass slides was subsequently converted to virtual slides and placed on the WebMicroscope server. Giving access to fully digitized slides on the web with a browser and a viewer plug-in, the computer has become a perfect companion of the student.

Results

The study material consists now of over 400 fully digitized slides which covering 15 entities in basic and systemic pathology and 15 entities in oral pathology. Digitized slides are linked with still macro- and microscopic images, organized with clinical information into virtual cases and supplemented with text files, syllabus, PowerPoint presentations and animations on the web, serving additionally as material for individual studies. After their examinations, the students rated the use of the software, quality of the images, the ease of handling the images, and the effective use of virtual slides during the laboratory practicals. Responses were evaluated on a standardized scale. Because of the positive opinions and support from the students, the satisfaction surveys had shown a progressive improvement over the past 5 years. The WebMicroscope as a didactic tool for laboratory practicals was rated over 8 on a 1-10 scale for basic and systemic pathology and 9/10 for oral pathology especially as various students’ suggestions were implemented. Overall, the quality of the images was rated as very good.

Conclusions

An overwhelming majority of our students regarded a possibility of using virtual slides at their convenience as highly desirable. Our students and faculty consider the use of the virtual microscope for the study of basic as well as oral pathology as a significant improvement over the light microscope.

     

Current state of whole slide imaging use in cytopathology: Pros and pitfalls

Whole slide imaging (WSI) allows generation of large whole slide images and their navigation with zoom in and out like a true virtual microscope. It has become widely used in surgical pathology for many purposes, such as education and training, research activity, teleconsultation, and primary diagnosis. However, in cytopathology, the use of WSI has been lagging behind histology, mainly due to the cytological specimen's characteristics, as groups of cells of different thickness are distributed throughout the slide. To allow the same focusing capability of light microscope, slides have to be scanned at multiple focal planes, at the cost of longer scan times and larger file size. These are the main technical pitfalls of WSI for cytopathology, partly overcome by solutions like liquid‐based preparations. Validation studies for the use in primary diagnosis are less numerous and more heterogeneous than in surgical pathology. WSI has been proved effective for training students and successfully used in proficiency testing, allowing the creation of digital cytology atlases. Longer scan times are also a barrier for use in rapid on‐site evaluation, but WSI retains its advantages of easy sharing of images for consultation, multiple simultaneous viewing in different locations, the possibility of unlimited annotations and easy integration with medical records. Moreover, digital slides set the laboratory free from reliance on a physical glass slide, with no more concern of fading of stain or slide breakage. Costs are still a problem for small institutions, but WSI can also represent the beginning of a more efficient way of working.     

Web-based scoring of the dicentric assay,a collaborative biodosimetric scoring strategy for population triage in large scale radiation accidents

In the case of a large scale radiation accident high throughput methods of biological dosimetry for population triage are needed to identify individuals requiring clinical treatment. The dicentric assay performed in web-based scoring mode may be a very suitable technique. Within the MULTIBIODOSE EU FP7 project a network is being established of 8 laboratories with expertise in dose estimations based on the dicentric assay. Here, the manual dicentric assay was tested in a web-based scoring mode. More than 23,000 high resolution images of metaphase spreads (only first mitosis) were captured by four laboratories and established as image galleries on the internet (cloud). The galleries included images of a complete dose effect curve (0–5.0 Gy) and three types of irradiation scenarios simulating acute whole body, partial body and protracted exposure. The blood samples had been irradiated in vitro with gamma rays at the University of Ghent, Belgium. Two laboratories provided image galleries from Fluorescence plus Giemsa stained slides (3 h colcemid) and the image galleries from the other two laboratories contained images from Giemsa stained preparations (24 h colcemid). Each of the 8 participating laboratories analysed 3 dose points of the dose effect curve (scoring 100 cells for each point) and 3 unknown dose points (50 cells) for each of the 3 simulated irradiation scenarios. At first all analyses were performed in a QuickScan Mode without scoring individual chromosomes, followed by conventional scoring (only complete cells, 46 centromeres). The calibration curves obtained using these two scoring methods were very similar, with no significant difference in the linear-quadratic curve coefficients. Analysis of variance showed a significant effect of dose on the yield of dicentrics, but no significant effect of the laboratories, different methods of slide preparation or different incubation times used for colcemid. The results obtained to date within the MULTIBIODOSE project by a network of 8 collaborating laboratories throughout Europe are very promising. The dicentric assay in the web based scoring mode as a high throughput scoring strategy is a useful application for biodosimetry in the case of a large scale radiation accident.     

Color standardization and optimization in Whole Slide Imaging

Introduction

Standardization and validation of the color displayed by digital slides is an important aspect of digital pathology implementation. While the most common reason for color variation is the variance in the protocols and practices in the histology lab, the color displayed can also be affected by variation in capture parameters (for example, illumination and filters), image processing and display factors in the digital systems themselves.

Method

We have been developing techniques for color validation and optimization along two paths. The first was based on two standard slides that are scanned and displayed by the imaging system in question. In this approach, one slide is embedded with nine filters with colors selected especially for H&;E stained slides (looking like tiny Macbeth color chart); the specific color of the nine filters were determined in our previous study and modified for whole slide imaging (WSI). The other slide is an H&;E stained mouse embryo. Both of these slides were scanned and the displayed images were compared to a standard. The second approach was based on our previous multispectral imaging research.

Discussion

As a first step, the two slide method (above) was used to identify inaccurate display of color and its cause, and to understand the importance of accurate color in digital pathology. We have also improved the multispectral-based algorithm for more consistent results in stain standardization. In near future, the results of the two slide and multispectral techniques can be combined and will be widely available.We have been conducting a series of researches and developing projects to improve image quality to establish Image Quality Standardization. This paper discusses one of most important aspects of image quality – color.

     

iPathology cockpit diagnostic station: validation according to College of American Pathologists Pathology and Laboratory Quality Center recommendation at the Hospital Trust and University of Verona

Background

Validation of digital whole slide images is crucial to ensure that diagnostic performance is at least equivalent to that of glass slides and light microscopy. The College of American Pathologists Pathology and Laboratory Quality Center recently developed recommendations for internal digital pathology system validation. Following these guidelines we sought to validate the performance of a digital approach for routine diagnosis by using an iPad and digital control widescreen-assisted workstation through a pilot study.

Methods

From January 2014, 61 histopathological slides were scanned by ScanScope Digital Slides Scanner (Aperio, Vista, CA). Two independent pathologists performed diagnosis on virtual slides in front of a widescreen by using two computer devices (ImageScope viewing software) located to different Health Institutions (AOUI Verona) connected by local network and a remote image server using an iPad tablet (Aperio, Vista, CA), after uploading the Citrix receiver for iPad. Quality indicators related to image characters and work-flow of the e-health cockpit enterprise system were scored based on subjective (high vs poor) perception. The images were re-evaluated two weeks apart.

Results

The whole glass slides encountered 10 liver: hepatocarcinoma, 10 renal carcinoma, 10 gastric carcinoma and 10 prostate biopsies: adenocarcinoma, 5 excisional skin biopsies: melanoma, 5 lymph-nodes: lymphoma. 6 immuno- and 5 special stains were available for intra- and internet remote viewing. Scan times averaged two minutes and 54 seconds per slide (standard deviation 2 minutes 34 seconds). Megabytes ranged from 256 to 680 (mean 390) per slide storage. Reliance on glass slide, image quality (resolution and color fidelity), slide navigation time, simultaneous viewers in geographically remote locations were considered of high performance score. Side by side comparisons between diagnosis performed on tissue glass slides versus widescreen were excellent showing an almost perfect concordance (0.81, kappa index).

Conclusions

We validated our institutional digital pathology system for routine diagnostic facing with whole slide images in a cockpit enterprise digital system or iPad tablet. Computer widescreens are better for diagnosing scanned glass slide that iPad. For urgent requests, iPad may be used. Legal aspects have to be soon faced with to permit the clinical use of this technology in a manner that does not compromise patient care.

     

Digital images for interobserver variability comparison in cervicovaginal cytology

OBJECTIVE: To assess whether digital images can be useful in evaluating interobserver variability in cervical-vaginal cytology. STUDY DESIGN: In phase 1 of the study, to measure interobserver variability, a set of 160 digital images was submitted to 192 cytologists with experience ranging from 2 to > 30 years. The set was preceded by two days of immersion in lessons and practical exercises with digital images. In phase 2, to compare different procedures of interobserver variability, two different sets of slides and one set of digital images were used. RESULTS: In phase 1, kappa and weighted kappa w values computed against both the consensus and the target diagnosis showed good agreement, with few exceptions. In phase 2, the consensus and target diagnoses obtained on the slide sets and digital set were compared. Mean k and kw values obtained with the digital images in phase 2 were significantly lower as compared to those in phase 1. CONCLUSION: A set of digital images can be a useful tool for evaluating and improving interobserver reproducibility. A two-day course on digital images could be an ideal modality for introducing this new technology.     

P‐15COMPARISON OF RESULTS FOR A NON‐GYNAECOLOGICAL CYTOLOGY EQA SCHEME

The problems encountered with a glass slide circulation are legion but timely circulation is a major problem and is an inherent deficiency of our Non‐gynaecological EQA scheme. This applies not only to consultants but also to specialist registrars (SpRs) and technical staff that are not formally included in the circulation list. In 2005 only 7 technical staff and 4 out of 47 SpRs took part on a formal basis, their participation being dependant on access to slides during their cytology attachment. The results for the 2005 circulation have been analysed and despite the small numbers of participating technical staff and SpRs their answers concur with the consultant body. To address the issues of timeliness and circulation problems a pilot teaching set has been developed by SlidePath into a virtual microscope web based circulation and sent to all SpRs in our region. They have recorded their answers and been given immediate access to the consensus consultant opinion with illustrations of follow up histology. A questionnaire was completed to evaluate the scheme. The facility of immediate feedback of consultant consensus is particularly pertinent to the educational element of the scheme and use of virtual microscopy addresses the issue of timely circulation. If further funding was made available technical staff could also be given the opportunity to try this web‐based circulation.     

Utility of 2-D and 3-D virtual microscopy in cervical cytology education and testing

OBJECTIVE: To evaluate the effectiveness of 3-D vs. 2-D virtual microscopy as adjuncts to education and assessment in cervical cytology. STUDY DESIGN: Five cervical cytology slides were acquired in 2-D; then the identical area of the slide was acquired in 3-D, resulting in 2 sets of virtual slides for comparison with the original glass slide. Seventy-nine paid volunteer cytologists and cytotechnology students participated. Approximately half were sent the 2-D set of slides via the Web, and the others a 3-D set of slides on a DVD. Evaluators examined the virtual slides and committed to an interpretation. After receipt of the original glass slides, a second interpretation was made, if different from the virtual slide interpretation. RESULTS: Diagnostic accuracy using virtual cytology slides was similar to that for glass slides (94% vs. 96%). There was no difference in diagnostic accuracy between 2-D and 3-D slides (p = 0.28); however, the ability to focus 3-D slides in the z-axis was strongly endorsed by the participants because of the uncertainty and frustration of having some cells out of focus on 2-D virtual slides. CONCLUSION: There was consensus that virtual cervical cytology slides would be a useful augmentation to education and testing.