Volume 34 Issue 4, Fall 2007, pp. 437-444

ABSTRACT

Virtual microscopy (VM) uses a computer to view digitized slides and is comparable to using a microscope to view glass slides. This technology has been assessed in human medical education for teaching histology and histopathology, but, to the authors’ knowledge, no one has evaluated its use in teaching cytopathology in veterinary medical education. We hypothesize that students will respond positively to the use of VM for viewing cytopathology preparations and that the technology can be successfully used for student assessment. To test this hypothesis, we surveyed students regarding their level of satisfaction with features of the VM system, their preference for use of VM in the curriculum, and the potential influence virtual slides may have on student study habits; student performance on a traditional cytopathology practical examination and a similar exam using VM was evaluated. Our results show that student perception of the VM system is generally very positive, with some concerns about resolution and the need for continued exposure to traditional microscopy. Within the curriculum, students indicated a preference for the option of using virtual slides for studying and take-home exercises. Overwhelmingly, students wanted either hybrid laboratory sessions or sessions using glass slides with virtual slides available for study and review. Students identified many VM test-taking features as advantageous compared with traditional glass-slide practical exams as traditionally administered. However, students indicated a strong preference for continued use of traditional microscopy for graded practical exams. Students may be more likely to study slides in preparation for practical examinations if virtual slides are available. Results also indicate that VM can be used successfully for assessment purposes, but students should receive training in using virtual slides if the technology will be used for assessment.

Virtual microscopy (VM) is the digital equivalent of traditional microscopy; rather than using a microscope to view glass specimen slides, it uses a computer to view digitized microscopic images of specimens. In order for the virtual microscope and virtual slide to be equivalent to a traditional microscope and glass slide, the system must have the following features: sufficiently high resolution to allow pertinent microscopic features to be identified; high-power magnification (equivalent of a 40× objective); the ability to change objectives or magnification; the ability to navigate on the slide (scan and find); and, for some specimens, fine focus. Digitization of the entire slide, or of a sufficiently large region for the intended purpose, is also necessary. Technology has now advanced to the point where all of these criteria can be met in a time-efficient and cost-effective manner, making the use of VM in veterinary and human medical education a viable alternative or supplement to traditional microscopy.1

VM offers some distinct educational advantages over traditional microscopy. With virtual slides, there is no loss, breakage, or fading of specimens, and large numbers of slides do not have to be prepared for teaching sets. Slide quality is uniform; all students can see the same thing. Slides can be selected for use based solely on their educational value, rather than on a combination of educational value and availability of sufficient specimen to complete a slide set. Slides that have previously been too valuable or scarce for use in teaching can now be used. Because images are digital, they can be annotated. They can also be accessed at any time outside of the laboratory setting via a high-speed Internet connection. VM may also reduce the number of microscopes an institution provides—an important consideration for programs with aging microscopes that will need replacing, programs that are expanding to accommodate larger classes, or those that have traditionally required students to purchase or rent their own microscopes.

Although VM is a very good simulation of traditional microscopy, it has two disadvantages: its inferior resolution and focusing ability and the inability of slide scanners to provide either magnification of 100× routinely or the use of oil-immersion lenses in the digitization process. Investing in the technology to produce, store, and view slides can be expensive, especially if elements such as a large networked computer laboratory are not already in place. Implementing and maintaining a storage and viewing system require expert technical support. Currently, many digitization processes and viewing systems are proprietary, leading to potential problems of incompatibility if multiple systems or scanners are used. There is also a risk that the technology will become obsolete or that the manufacturer will cease to support it. In addition, students who learn using VM may not become technically proficient with a real microscope.2, 3

Despite these potential disadvantages, more and more human medical schools are turning to VM as a supplement to or replacement for traditional microscopy for histology and pathology courses. To our knowledge, however, no one has examined the use of VM for the teaching and assessment of cytopathology within a veterinary course.4–11 We hypothesized that students would respond positively to using VM for viewing cytopathology preparations and that the technology can be successfully used for assessment of student performance in cytopathology. In order to test this, we evaluated students’ performance on a standard glass-slide practical cytopathology exam and a similar virtual exam and surveyed students regarding their level of satisfaction with various aspects of the VM system and their preferences for future use of VM within the curriculum.

Students were trained in cytopathology by the following methods:

  1. Students received instructor notes and attended six lectures in which PowerPointa presentations were used to illustrate and emphasize important concepts and cytologic interpretations. PowerPoint presentations were available to students on the course Web site.

  2. Students completed two laboratory sessions in which four instructors were available for help and questions. Within each session, students were required to work through five or six unknown cytology specimens for laboratory credit and examine six to 10 additional demonstration slides. Following each laboratory session, one complete set of glass slides was made available for after-hours study within the teaching laboratory and were available 24 hours a day, seven days a week. In addition, one set of slides from each laboratory session was set up by the instructor for the weekend prior to the glass-slide practical exam to facilitate student studying.

Exam
Glass Slide Exam

Students were given a practical cytopathology examination using glass slides and standard light microscopes. The test consisted of 20 glass slides, each assigned the same point value. Students were required to provide an interpretation for each slide; for a list of slides and interpretations, see Table 1. Two sets of 20 slides (A and B) were used in order to accommodate the constraints of class size and test duration. Sets were well matched, and the interpretations for each set were identical. A small diagnostic region of the slide representing a single 4× field of view (approximately 20 mm2) was circled by the instructor (author JN), and slides were set into this region prior to the exam. Students were instructed to remain within the circled region and could view the slide using 4×, 10×, and 40× objectives. Microscope stations consisting of a single slide per microscope were set up, and students rotated through the stations. Two minutes were allowed at each station, and students were given an additional 15 minutes at the end of the test to revisit any station. Total test time was 55 minutes. Grading was performed by the instructor.

Table

Table 1: Cytopathology practical exam specimens and interpretations

Table 1: Cytopathology practical exam specimens and interpretations

Slide # Specimen Interpretation*
1 Canine lymph node Lymphoma
2 Canine perianal mass Apocrine gland adenocarcinoma
3 Canine lymph node Metastatic carcinoma
4 Canine perianal mass Perianal gland adenoma
5 Canine pleural fluid Carcinoma
6 Canine mandibular lymph node Salivary tissue
7 Canine skin mass Mast cell tumor
8 Canine skin mass Histiocytoma
9 Canine skin mass Plasmacytoma
10 Canine subcutaneous mass Lipoma
11 Canine subcutaneous mass Epithelial/follicular cyst or tumor with follicular differentiation
12 Canine submandibular mass Mucocele
13 Canine ulcerated cutaneous lesion Blastomycosis
14 Canine subcutaneous mass Sarcoma
15 Equine abdominal fluid Septic suppurative inflammation
16 Feline lymph node Eosinophilic lymphadenitis
17 Feline mandibular mass Melanoma
18 Feline nasal mass Cryptococcosis
19 Feline pleural fluid Chylous effusion
20 Canine lymph node Reactive/hyperplastic lymph tissue

*Interpretation does not include alternative full-credit or partial-credit answers

Virtual Slide Exam

Twenty glass slides were digitized by Bacus Laboratories Inc.b using the BLISS Virtual Slide Scanning system, as previously described;12 10 slides from glass test set A and 10 slides from glass test set B were selected for scanning. All slides were scanned in their entirety for low-power viewing at magnifications of 0.16×, 0.31×, 0.63× and 1.25×. A diagnostic region of each slide was selected by the instructor for high-power scanning; selection of highest-power magnification was based on the specimen. The area scanned per slide ranged from 7.5 mm2 to 110 mm2, with an average of 39.9 mm2. Thirteen slides were scanned with a 40× objective, resulting in magnifications of 5×, 10×, 20×, and 40×; two slides were scanned with a 20× objective, for magnifications of 2.5×, 5×, 10×, and 20×; five slides were scanned with a 63× dry objective, for magnifications of 7.88×, 16×, 32×, and 63×. Three slides also had z-plane scanning for fine focusing; selection was based on the specimen.

One week after taking the glass-slide exam, but before exam results were released, students were given the opportunity to retake the same exam using VM; prior to this point, students were not aware that a second exam would be administered. The highest of the two exam grades was recorded as the official score for each participating student. The exam was administered in a secure computer laboratory setting using standard PCs and was proctored by the instructor. Students viewed the slides using WebSlide Browser software from Bacus Laboratories Inc.c Students were oriented to the software program at the time of the virtual exam and had had no previous exposure to virtual microscopy within the required coursework of the veterinary curriculum. Students were given 55 minutes to complete the exam. No time limit per slide was given, and students could review previously viewed slides at any time. Grading was carried out by the instructor using the same key constructed for the original exam.

Survey

At the end of the virtual exam, students were asked to fill out an anonymous survey, which asked them to

  • rate various VM system features (see Tables 2 and 3);

    Table

    Table 2: Student survey results for VM system features, Set I

    Table 2: Student survey results for VM system features, Set I

    Virtual microscopy system features Rating*

    1 2 3 4 5 Mean Rating
    Ease of use 43.5% 37.1% 11.3% 6.5% 1.6% 1.9
    Low-power orientation view showing area currently viewed on high power 50.8% 26.2% 13.1% 8.2% 1.6% 1.8
    Ability to use a computer instead of a microscope to view slides 24.2% 29.0% 22.6% 17.7% 6.5% 2.5
    Fine-focus feature 24.2% 22.6% 37.1% 8.1% 8.1% 2.5
    Resolution (ability to see detail) 6.5% 30.6% 30.6% 19.4% 12.9% 3.0

    *1 = excellent/I liked it a lot; 5 = poor/I didn't like it at all. Ratings of 1 or 2 are considered positive, a rating of 3 is considered neutral, and ratings of 4 or 5 are considered negative.

    Table

    Table 3: Student survey results for VM system features, Set II

    Table 3: Student survey results for VM system features, Set II

    Virtual microscopy system features Rating*

    1 2 3 4 5 Mean Rating
    Time delay when moving around on the slide 66.1% 21% 8.1% 3.2% 1.6% 1.5
    Time delay when using the fine-focus feature 65.6% 21.3% 9.8% 3.3% 0% 1.5
    Viewing the fine focus in a separate pop-up window 54.1% 26.2% 11.5% 4.9% 3.3% 1.8
    Lack of a 100× objective view 37.1% 22.6% 22.6% 11.3% 6.5% 2.3

    *1 = feature didn't bother me at all; 5 = feature bothered me a lot. Ratings of 1 or 2 are considered non-bothersome, a rating of 3 is considered neutral, and ratings of 4 or 5 are considered negative or bothersome.

  • indicate their preferences for use of glass microscopy versus VM for various course assessment activities (see Table 4);

    Table

    Table 4: Student survey results: Preference for virtual versus traditional microscopy in course assessment activities

    Table 4: Student survey results: Preference for virtual versus traditional microscopy in course assessment activities

    Activity Preference

    Virtual Glass No Preference
    Graded practical exams 16.1% 71% 12.9%
    Take-home quizzes or exercises 80.6% 17.7% 1.6%
    Studying* 72.6% 27.4% 11.3%

    *11.3% of students selected both virtual and glass.

  • indicate their preferences for use for VM and traditional microscopy for laboratory sessions (see Table 5);

    Table

    Table 5: Student survey results: Preferences for virtual versus traditional microscopy for laboratory sessions

    Table 5: Student survey results: Preferences for virtual versus traditional microscopy for laboratory sessions

    Laboratory Sessions Conducted Using Preference (%)
    Only virtual slides 4.8
    A mix of glass slides and virtual slides 45.2
    Only glass slides during sessions, with virtual slides available for studying 50.0
    Only glass both for the laboratory sessions and for studying 0.0

  • estimate the current amount of time they spent studying glass slides outside of laboratory sessions in preparation for practical exams (see Table 6);

    Table

    Table 6: Student survey results: Current study habits and projected VM study habits

    Table 6: Student survey results: Current study habits and projected VM study habits

    Study Habits Rating

    1 2 3 4 5 Mean Rating
    Time currently spent outside of scheduled lab sessions reviewing glass slides for practical exams* 3.2% 21.0% 45.2% 17.7% 12.9% 3.2
    Additional time you would spend studying outside of scheduled lab sessions if virtual slides were available** 27.4% 46.8% 16.1% 6.5% 3.2% 2.1

    *1 = I spend a lot of time outside of lab; 5 = I don't spend any time outside lab. Ratings of 1 or 2 are considered indicative of large amounts of time, a rating of 3 is considered indicative of moderate amounts of time, and ratings of 4 or 5 are considered indicative of little or no time.

    **1 = I would spend a lot more time; 5 = I wouldn't spend any more time. Ratings of 1 or 2 are considered indicative of large amounts of time, a rating of 3 is considered indicative of moderate amounts of time, and ratings of 4 or 5 are considered indicative of little or no time.

  • estimate the amount of additional time they would spend studying slides in preparation for practical exams if VM were available (see Table 6); and

  • rate various VM test-taking features (see Table 7).

    Table

    Table 7: Student survey results: VM test-taking features

    Table 7: Student survey results: VM test-taking features

    Virtual Microscopy Test Features Rating*
    1 2 3 4 5 Mean Rating
    Ability to review previously viewed slides at any time 71% 19.4% 8.1% 1.6% 0% 1.4
    Ability to choose how much time to spend on each slide 64.5% 19.4% 8.1% 6.5% 1.6% 1.6
    Ability to move freely from slide to slide 59.7% 17.7% 14.5% 4.8% 3.2% 1.7
    Ability to take the test in a more comfortable environment 38.7% 22.6% 24.2% 8.1% 6.5% 2.2
    Not having to adjust a microscope 22.6% 12.9% 21% 16.1% 27.4% 3.1

    *1 = feature is a major test-taking advantage; 5 = feature provides no test-taking advantage. Ratings of 1 or 2 are considered to indicate an advantage, a rating of 3 is considered neutral, and ratings of 4 or 5 are considered to indicate little or no advantage.

A total of 62 students (82.7% of those enrolled in the course) participated in the study; all 62 completed the survey, and 55 (73.3% of those enrolled) completed the virtual exam for grading. Seven students were unable to complete the virtual exam for grading purposes because of technical difficulties but felt able to complete the survey. All seven were offered the opportunity to retake the exam at a later date, but all declined, citing the time pressures of final exam week.

Survey Results

Tables 1 to 6 show survey results. Briefly, 80.6% of students found the VM system easy to use and 77% responded favorably to the low-power overview that locates the area of the slide currently being viewed on high power. Just over half of students responded positively to using a computer instead of a microscope, while the remaining students were divided almost equally between neutral and negative ratings; 46.8% of students gave a positive rating for the fine-focus feature, while 37.1% were neutral. Of all the various features, resolution had the lowest positive rating (37.1%) and the highest negative rating (32.3%).

The majority (87.1%) of students were not bothered by time delays while navigating on slides. Similarly high percentages of students did not mind the time delay when using the fine-focus feature (86.9% non-bothersome rating) or viewing the fine-focus feature as a separate pop-up window (80.3% non-bothersome rating). Students found the lack of a 100× objective more disagreeable: only 37.1% of students gave this feature a non-bothersome rating, and 17.8% identified it as a negative feature.

Students showed a strong preference for traditional microscopy for graded practical exams but preferred the option of VM for take-home quizzes or exercises and for studying: 71% of students preferred traditional glass microscopy for graded practical exams, 80.6% preferred the option of using VM for take-home quizzes or exercises, and 72.6% wanted to use virtual slides for studying. Students also showed a strong preference for the use of VM in the laboratory sessions, with 95.2% indicating that they would prefer some combination of glass and virtual slides; 45.2% wanted an in-laboratory mix of virtual and glass slides, while 50% preferred laboratories using only glass slides, with virtual slides available for studying. Few students wanted only VM for laboratory exercises, and no students preferred to use only glass slides for laboratory sessions as well as for studying.

Survey results indicate that most students feel they spend a moderate or large amount of time studying glass slides outside of scheduled laboratory sessions in preparation for graded practical exams, but 30.6% spend little or no time studying. Were virtual slides available, 74.2% of students projected that they would spend a large amount of additional time studying. Of the 30.6% who currently spend little or no time outside of laboratory sessions studying glass slides, 100% indicated that they thought they would spend additional time studying if virtual slides were available; 94.7% indicated they felt they would spend a large amount of additional time.

Students identified several VM test-taking features as highly advantageous. Features with high positive ratings include the ability to review previously viewed slides at any time (90.4% positive ratings), the ability to choose the amount of time spent per slide (83.9% positive ratings), and the ability to move freely from slide to slide (77.4% positive ratings). Taking the virtual exam in a more comfortable computer-laboratory environment was considered an advantage by 61.3% of students. Not having to adjust a microscope was not identified as a significant advantage; only 35.5% of respondents gave this a positive rating, while 43.5% indicated that there was no test-taking advantage to this feature.

Fifty-one students (82.3%) wrote remarks in the “additional comments” area of the survey; three main themes emerged. The most frequent statement (by 32.3% of students) was that VM would be most valuable or useful as a study aid. One-quarter (25%) of students noted that the virtual slides had poor resolution, that they were “fuzzy,” or there was poor focus at higher magnifications; some indicated that they felt this was a major disadvantage compared with glass slides. The third most common remark (from 19.4% of students) relates to the perceived need for continued exposure to traditional microscopy within the curriculum. These students felt strongly that continued practice using a microscope in the curriculum is necessary because they will need to be proficient with microscopy for private practice. Other comments ranged from very positive statements about the technology to practical statements, such as reports of “not getting seasick” while using VM and comments to the effect that students would likely become more accustomed to the system with increased exposure.

Test Results

Grade distribution and mean test scores on the glass-slide exam did not differ significantly between students who took the virtual exam and those who did not. Overall, students lost an average of 9.35 percentage points on the virtual exam; 14.5% achieved a higher score, 12.7% received the same grade, and 72.7% lost points. For those who improved their grades, improvement ranged from 5 to 22.5 percentage points, with half gaining ≤7.5 percentage points and half gaining ≥10 percentage points for an average gain of 11.9. Of students who lost points on the virtual exam, 27.3% lost 2.5–7.5 percentage points, 32.7% lost 10–22.5 percentage points, and 12.7% lost 25–45 percentage points. Half (50%) of students who performed in the bottom quarter on the glass-slide exam remained in the bottom quarter on the virtual exam; 78.6% of those who performed in the top quarter on the glass-slide exam remained in the top quarter on the virtual exam. Students in the bottom quarter on the glass-slide exam lost an average of 3.4 percentage points, while those in the top quarter lost an average of 6.6 percentage points. Students in the middle 50% had the greatest point loss, at an average of 14.7 percentage points.

A very high proportion of students found the VM system easy to use, which is significant because they had had no prior exposure to virtual slides and indicates that the technology should be easy to integrate into the curriculum. Most of the features of the VM system were perceived as positive or non-bothersome. These findings accord with those of previous studies, in which students have given high ratings to ease of use and other features of VM.4–6, 8–12

Resolution on the VM system caused some problems. Resolution of virtual slides does not yet compare with that of a good microscope. However, in the opinion of the instructors who have worked with the VM system, it is more than sufficient for slides in which very fine detail is not required for a diagnosis and was certainly sufficient for a correct interpretation on all the virtual test slides used in this study. While some previous studies have documented similar student comments regarding high-power resolution of fine detail,8 most indicate that students generally gave high or positive ratings for image quality.5, 7, 8, 10 Part of the reason for the discrepancy between previous studies and this study may relate to the specimens used: the cited studies used virtual histology and histopathology slides, whereas our specimens were cytopathology preparations. We have observed that uniform focus is more consistent with tissue sections than with cytology specimens, which often have varying levels of thickness throughout the slide.10 In addition, cytology often emphasizes fine cellular detail, whereas histology and histopathology focus more on tissue architecture, with less attention to fine high-power detail. Increased use of z-axis scanning for fine focusing does improve focus ability in cytology specimens, but it also causes a significant increase in file size and acquisition time. We anticipate that students’ concerns about resolution will lessen with increased exposure to virtual slides within the course as they become accustomed to viewing virtual slides. In addition, advances in technology that enable easier use of oil-immersion objectives in slide scanning or employ new methods for acquiring optimal focus will likely yield better resolution.

Use of VM for testing can offer some distinct advantages over traditional microscopy and has even been incorporated into the board certification exams given by the American Board of Pathology.3 From the instructor's point of view, the use of virtual slides eliminates the need for more than one set of exam slides, eliminates physical set-up and break-down of exams, and ensures that each student has the same view of the slides. However, major disadvantages include the need to administer exams in a secure setting, the need to have enough computers available for testing purposes, and the possibility of a system failure.8 Based on responses to our survey, students clearly felt that many of the features available in the virtual exam offered a major advantage over glass practical exams at our institution. This is not to say that the same features could not be provided in a traditional glass-slide exam; certainly many or all could be provided and, in fact, are provided for the American College of Veterinary Pathologists board examination (clinical and anatomic pathology). However, there can be significant difficulties in providing these features on a glass cytopathology exam for a large class of veterinary students. Enough slides would need to be available to allow each student (or, potentially, each pair of students) a complete set of slides and to allow for all students to finish testing within the allotted time frame. Often it is difficult to find more than a few high-quality, well-matched slides that exhibit classic features and are free of interfering or misleading artifacts. At our institution, this would require identifying up to 40 copies of each slide, which would significantly limit what specimens could be used for testing.

Despite identifying significant potential advantages of using VM as a testing modality, students overwhelmingly preferred glass slides for exams, primarily because they felt that testing with glass slides was more indicative of what they would need to do “in the real world” or because they felt the better resolution of the glass slide was an advantage. It is also possible that students’ preference was influenced by the difference in difficulty between the two exams and their presumably greater level of preparedness for the glass-slide exam. We anticipate that increased exposure to VM within the curriculum will result in increased student acceptance of, or even preference for, the use of VM for assessment purposes.

While students favored traditional microscopy for exams, they indicated a strong desire to have access to virtual slides for studying purposes, take-home exercises, and laboratory exercises. These results are similar to those of previous studies, in which students indicated a strong preference for virtual slides for laboratories and studying; many cited increased efficiency, ease of use, accessibility, and better student–student and student–instructor interactions as major reasons.4, 6, 10 Our results also suggest that students may spend more time studying slides (as opposed to static images) in preparation for exams if virtual slides are available.

Because the features of VM accurately simulate traditional microscopy, studying using virtual slides allows students to hone skills essential to cytopathology that cannot be easily or effectively mastered using static images: effective low-power scanning, identifying good regions for high-power examination (thin region, good stain quality, intact cells), and understanding the necessity of examining multiple regions on high power before rendering a diagnosis. We anticipate that any increase in studying of slides due to the availability of virtual slides will result in a greater ability on the part of students to examine cytopathology specimens successfully.

In most traditional microscopy systems used for teaching large numbers of students, only a single person—or two people, if using a dual-headed microscope—can easily view a slide at one time. This creates an obstacle for students trying to share information about what they are seeing on different slides and for instructors attempting to demonstrate various features of a slide to groups of students; often the result is repetitive actions such as students waiting to take turns looking at different microscopes and instructors demonstrating the same items over and over to a series of students. While this effect can be alleviated to some degree by demonstrating slides via video or digital camera, it does not facilitate small-group discussions among students or by students and instructors; rather, it is most effective for reviewing slides with the entire group. When slides are viewed on a screen, more individuals can see the slides at once, which allows students to more easily compare differences between slides and instructors to more efficiently demonstrate or discuss important features of a slide to larger numbers of students while still maintaining a small-group focus. Because of these features, we anticipate that use of virtual slides in the laboratory setting will result in greater interaction between students and between students and instructors. Such results have previously been reported.4, 6, 10 In addition, one study also documented a high level of acceptance of, and preference for, teaching with virtual slides on the part of laboratory instructors, who felt more confident in helping students using virtual slides because areas or structures of concern could be easily identified on the computer screen and because discussing slides viewed by a group of students on a screen promoted more efficient teaching.6, 8

Some students felt very strongly that continued use of traditional microscopy within the veterinary curriculum is essential, since they will need to use microscopes in clinical practice to examine a variety of in-house preparations. Previous studies of human medical students have documented similar concerns among some students4, 6, 8 but, overall, indicate a high level of acceptance of or preference for VM. It can be argued that most physicians do not routinely use microscopes within their practice, while many veterinarians evaluate a number of in-house specimens, including blood smears, cytology preparations, fecal sediments and smears, and urine sediments. Additionally, physicians who need to learn to use a microscope can do so during specialty training, whereas most veterinary students receive no specialty or advanced training prior to general practice and, therefore, need continued exposure to traditional microscopy within the curriculum. We believe that traditional microscopy is a skill that veterinary students need to master, but this does not exclude using VM as a teaching and learning tool. There are some specimens that private practitioners are unlikely to examine in practice because specialized processing equipment or advance training is needed for evaluation (e.g., histology and histopathology slides). It is possible that courses using these types of specimens could be taught using only VM, while courses such as clinical pathology and parasitology could be taught with a combination of glass and virtual slides to allow students to gain proficiency with light microscopes. It is also possible that exposure to “real” microscopy could occur primarily in the clinical year, with little or no negative impact on the ability of students to gain proficiency in using a microscope. Additional studies may be necessary to assess the impact that incorporating VM within the veterinary curriculum has on students' mastery of microscopy.

Several flaws in the study reported here prevent a true comparison of student performance on the traditional and virtual exams, but results do indicate that VM can be used for student assessment in veterinary cytopathology education. These flaws have almost certainly introduced a bias against performance on the virtual test and student preferences for graded practical exams:

  1. Students could not lower their grades by taking the virtual test, and they could only improve them, so for those who were currently satisfied with their course performance, there was no incentive to try to achieve a higher score.

  2. The overall stakes were low, as the cytopathology practical exam was worth only 3.33% of the total course grade.

  3. As the virtual exam was offered one week after the glass-slide practical exam and coincided with the first day of final exam week, it is unlikely that students devoted additional study time to preparing for the virtual exam; as a result, they may have actually been less well prepared than they were for the original exam.

  4. The technology was new; students had not been trained in cytopathology using virtual slides and did not have an opportunity to work with the computer program or with virtual slides prior to being oriented at the time of the exam.

  5. The viewing area of the slides differed between glass and virtual slides. The virtual slides typically had a larger area available for high-power viewing, sometimes up to four or five times as much. Because of this, students had to be able to navigate to a suitable region, as well as identify and interpret the cytologic findings, for the virtual exam. Thus, the virtual exam may have tested a broader (and more realistic) range of skills than the glass-slide practical exam, which tested only recognition skills and not the ability up to find appropriate regions for examination. Incorporating VM into regular coursework to allow students to train using both traditional glass microscopy and VM, followed by a crossover study, would allow a better direct comparison of student performance.

In light of these study flaws, the grades and survey results are encouraging and may be more positive than the data suggest. On the virtual exam, 54.5% of students improved their grade, achieved the same grade, or lost a small number of points, and overall student survey results were positive. Previous studies using VM, either in student assessment activities or in course preparation for exams, have found either similar grades (glass and VM) or a slight improvement with use of virtual slides.6 We anticipate similar results once use of VM is incorporated into the coursework in upcoming years.

VM is a new and powerful technology that can serve as a valuable teaching, learning, and assessment resource in veterinary medical education. We plan to expand the role of VM in teaching and assessment of veterinary cytopathology and will begin incorporating it in teaching veterinary hematology. Initial survey results are positive, and we anticipate increased student satisfaction and preference for VM with greater exposure to the technology.

ACKNOWLEDGMENTS

Funding for this project was provided by North Carolina State University's Learning in a Technology-Rich Environment (LITRE) grant program and the North Carolina State University, College of Veterinary Medicine, Educational Grant program.

NOTES

a Microsoft Corp., Redmond, WA 98052-6399 USA <http://www.microsoft.com/>.

b Bacus Laboratories, Inc., Lombard, IL 60148 USA <http://www.bacuslabs.com/>.

c Bacus Laboratories, Inc., Lombard, IL 60148 USA <http://www.bacuslabs.com/>.

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