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Year : 2019  |  Volume : 62  |  Issue : 1  |  Page : 84-90
Randomized cross-over study and a qualitative analysis comparing virtual microscopy and light microscopy for learning undergraduate histopathology

1 Department of Pathophysiology, Windsor University School of Medicine, St. Kitts and Nevis
2 Department of Public Health and Preventive Medicine, St. George's University School of Medicine, St. George's, Grenada

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Date of Web Publication31-Jan-2019


Background: Virtual microscopy (VM) use in teaching and learning is increasing worldwide. However, there is a paucity of information comparing it to light microscopy (LM) in learning undergraduate histopathology. We investigated whether VM or LM had a higher impact on student learning and performance in histopathology. In addition, we investigated whether students preferred VM over LM, and whether VM use provided a platform to fulfill the Accreditation Council for Graduate Medical Education core competencies. Materials and Methods: We used a sequential exploratory mixed method study design. A qualitative phase inquiring about student preference for VM or LM was followed by a randomized cross-over study. Student preference was measured by an online survey based on a Likert scale. In the cross-over study, students were randomized to either the VM or the LM arm, and their mean scores in standardized exams were compared after using VM and LM. Results: A total of 152 students completed the qualitative study and a total of 64 students participated in the cross-over study. Eighty-three percent (83%) of the students preferred to use VM over LM. Students who used VM scored significantly (P < 0.001) higher [(87.1% vs. 72.4%) and (85.3% vs. 76.1%)], respectively, in both phases of the cross-over study compared to those who used LM. Conclusions: Using VM to learn histopathology has significantly increased student learning and performance compared to using LM.

Keywords: Competency-based education, digital histopathology, light microscopy, undergraduate medical education, virtual microscopy, whole slide imaging

How to cite this article:
Nauhria S, Ramdass P. Randomized cross-over study and a qualitative analysis comparing virtual microscopy and light microscopy for learning undergraduate histopathology. Indian J Pathol Microbiol 2019;62:84-90

How to cite this URL:
Nauhria S, Ramdass P. Randomized cross-over study and a qualitative analysis comparing virtual microscopy and light microscopy for learning undergraduate histopathology. Indian J Pathol Microbiol [serial online] 2019 [cited 2021 Dec 1];62:84-90. Available from: https://www.ijpmonline.org/text.asp?2019/62/1/84/251241

   Introduction Top

The primary objective of medical education is to foster a learning environment for interactive discussion, independent thinking, and self-directed learning. This approach is necessary to produce competent diagnostic clinicians who will be able to function effectively as leaders and team members. Several programs around the world have stringently adopted the competency-based education (CBE) system for imparting undergraduate medical education.[1],[2],[3],[4] The core competencies outlined by the Accreditation Council for Graduate Medical Education (ACGME) include patient care, medical knowledge, communication skills, professionalism, practice-based learning improvement, and systems-based practice.[5] The Medical Council of India (MCI) also has proposed adoption of competencies in medical education.[6]

And the increasing use of electronic media in teaching programs has paved a path to address some of these core competencies in both undergraduate and postgraduate programs.[7],[8] Virtual microscopy (VM) is one facet that has revolutionized learning histopathology worldwide. Whole slide imaging (WSI) technique allows digitization of glass slides in a high-resolution format which can be conveniently viewed using specialized software on a computer or handheld tablet devices. VM software produces high-quality images with meticulous clarity, and also has additional features that allow students to highlight, annotate, and pan and zoom (up to a maximum of ×100) WSI.[9]

Areas of VM use in undergraduate pathology education encompass various active learning activities like small-group discussions, laboratory sessions, integrated case-based discussions (ICD), and problem-based learning (PBL). It has also been adopted in the field of cytology, hematology, and for continuing medical education (CME).[10] Several studies have shown the positive impact of VM in various learning environments, and there is ample evidence that indicates high acceptability and adaptability by several medical schools across the globe.[11],[12],[13]

The transition from conventional light microscopy (LM) to VM use has reshaped the agenda for undergraduate medical education as per the Liaison Committee on Medical Education (LCME) which requires all US medical schools to outline their curriculum regarding educational objectives.[4],[14] The accrediting bodies for US medical schools are the LCME and ACGME, which play a vital role in residency training for many students from medical schools in the Caribbean. However, the utilization of VM is entirely new to medical schools in the Caribbean as well as most Indian medical colleges. To date, no data are available on VM and WSI use for teaching undergraduate medical education in these regions.

Thus, we aim to compare student performance in standardized exams after learning histopathology with either LM or VM. In addition, we investigated whether students had a preference for LM or VM in learning histopathology and whether VM use provided a platform to fulfill the ACGME core competencies. We hypothesized that students who use VM will score higher in exams compared to those who use LM and that they will prefer to use VM over LM.

We also wanted to assess the cost of implementation of such a system for teaching purposes.

   Materials and Methods Top

Study design and participants

We used a sequential exploratory mixed method study design. The study was approved by the university institutional review board and was conducted by the Department of Pathophysiology from January 2017 to March 2018. Data were obtained from second-year medical students (semesters three and four) in the undergraduate pathology course. Informed consent was obtained from all students.

Data collection

The initial phase of the study involved qualitative data collection from one group of students from January 2017 to December 2017. This was followed by a quantitative study, which took the form of a randomized cross-over study with a different group of students from January 2018 to March 2018.

Qualitative data

Students completed an online survey delivered via Google forms after using the VM software for interactive histopathology sessions. Each student attended an average of four interactive sessions. Students had experience with LM in earlier semesters during histology sessions. The survey included questions on students' preference for either VM or LM, ease of use and benefits of VM, and statements on the six ACGME core competencies. A total of 18 statements were included in the survey. All questions in the survey were scored on a 5-point Likert scale (5: strongly agree, 4: agree, 3: neutral, 2: disagree, and 1: strongly disagree). A comments section was also included in the survey to explore students' experiences of the VM and their learning approaches.

Quantitative data

Students were stratified by sex, age, geographical region of origin, academic performance [based on previous National Board of Medical Examiners (NBME) average exam scores], and semester, and were then randomized into two groups. The study consisted of two phases: phase one (T1) and phase two (T2) [Figure 1]. During T1, 32 students were placed into the VM group and 32 students were placed into the LM group. This was followed by T2, in which students from the VM group were placed in the LM group, and vice versa. During each interactive session, both study arms viewed an average of five histopathology slides (LM group: glass slides; VM group: WSI). Clinical information related to each slide (history, clinical and lab findings, radiographs) was presented to all students via an online learning management system based on Moodle platform.[15] Each student completed two interactive sessions during T1 and two interactive sessions during T2, and the mean scores for each two-session phase were calculated.
Figure 1: Randomization and assessment protocol for virtual microscopy/light microscopy groups

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Before the start of the interactive sessions for both T1 and T2, students were given an assessment (pretest score) and were asked to score the level of difficulty of the questions (pretest difficulty). After all interactive sessions, students were also given an assessment (posttest score) and were also asked to score the level of difficulty of the questions (posttest difficulty). The difficulty rating was on a Likert scale from 1–10 (1: very easy; 10: very difficult). The questions used for the study were from an existing question bank with similar difficulty to the NBME questions. The assessment consisted of multiple choice questions and short-answer type questions regarding the microscopic description, differential diagnosis, or clinical features of the disease that measured different aspects of learning: knowledge, combined comprehension and application, and problem-solving ability.

Students in the VM group were provided with access to the new VM module, and the LM group was provided with access to existing LM resources.

Virtual microscopy module

Students in the VM group were given a live demonstration on how to use the VM software by the pathology faculty at the beginning of the interactive learning sessions. During these sessions, VM group students had hands-on experience with the VM software. A high-quality whole slide image set (average image size: 500 megabytes), acquired from the University of Iowa, was used for these sessions. The images were set up on a regular low cost server system and the students were given access to the same from individual computers which were connected via local networking. The images were then viewed via Leica Biosystems Aperio ImageScope free software which provided rapid access to the WSI.[16] With this software, students were able to adjust magnification, pan and zoom, annotate, perform image analysis, and compare different stains [Figure 2].
Figure 2: A working virtual microscopy session

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Light microscopy module

The LM group was provided with a set of glass slides depicting findings from the similar cases as provided to the VM group. These were viewed using Nikon E100 LED binocular microscopes.

Data analysis were performed to compare the mean exam scores and the mean exam difficulty using the independent samples t-tests. The Chi-squared test was used to compare categorical socio-demographic variables. A P value of <0.05 was considered statistically significant. All data were analyzed with IBM SPSS statistics software v24.0.

   Results Top

The mixed method design allowed us to explore the extent to which qualitative data (online survey) complemented the quantitative data (knowledge test scores). A total of 152 students completed the qualitative phase and a total of 64 students participated in the quantitative phase of the study.

Qualitative phase

The response rate for the survey was >90%. Eighty-three percent (83%) of students preferred to use VM over LM, while 17% were neutral. The majority (more than 70%) of students also reported that they agreed VM is easy to use and will benefit them in preparing for the NBME exams [Figure 3]. At least 60% of students indicated that they agreed VM use is vital in preparing them for all ACGME core competencies, except for patient care (50%). Professionalism (average 78%) and communication skills (average 75%) were the two core competencies that students reported will be impacted the most as a result of VM use [Figure 4].
Figure 3: Overall student preferences (virtual microscopy vs. light microscopy)

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Figure 4: Student preferences concerning Accreditation Council for Graduate Medical Education core competencies

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Comments by students were as follows: “The lab sessions are very productive”, “This is a cost-effective method that enhances students learning in pathology”, “The slides are very clear, and this system helps students learn more effectively”, “I like being able to apply the information that was obtained in the classroom lectures”, “I like observing pathology slides much more on the computer versus using a microscope”, “I find that I can see better details by using the software on the computer”, “I don't have to focus a real microscope”, “It is fun”.

The pathology faculty commented: “This teaching system saved a lot of time and effort.”

The Cronbach Alpha reliability statistics score of the questionnaire used for the feedback survey was 0.96. Item analysis for the questionnaire responses is shown in [Table 1].
Table 1: Item analysis for the questionnaire responses

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Quantitative phase

The two groups had a total of 32 students each in both phases of the cross-over study. There was no statistical difference between the two groups regarding demographic variables and academic performance (during T1 and T2). In addition, the mean pretest exam scores and pretest difficulty scores were similar for the VM group and the LM group during T1 and T2. However, the VM group achieved a significantly higher mean percentage score (87.1%; P < 0.001) and (85.3%; P < 0.001), compared to the LM group (72.4%) and (76.1%), in T1 and T2, respectively. Students also scored significantly lower in posttest difficulty for the VM group compared to the LM group in both T1 and T2 [Table 2] and [Table 3].
Table 2: Results for T1 phase

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Table 3: Results for T2 phase

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Percentage improvement from pretest to posttest during T1 phase was 41.4% for the VM group as compared to 22.1% improvement in the LM group. Similarly, result during T2 phase the improvement from pretest to posttest was 30.8% for the VM group as compared to 14.2% for the LM group.

   Discussion Top

Our study showed that students preferred to use VM over LM when learning histopathology and quantitative data (knowledge test scores) concurred with the qualitative data (online survey opinion). Recent studies have shown the increasing use of VM as an effective method to teach histopathology.[17],[18] The use of VM for teaching medical students has become widespread and remarkably successful.[19],[20] Previous studies have also reported that both students and instructors enjoy using WSI as a teaching-learning aid.[11]

Data from our study also revealed that a significant proportion of students agreed that VM could also be adapted to meet the requirements of ACGME core competencies. Professionalism and communication were among the top selected core competencies from our findings.

Researchers at other institutions have also reported findings similar to our study.[21] With the use of VM, laboratory or interactive learning sessions can incorporate clinical cases and problem-based learning (PBL). These formats will challenge the students by presenting a vignette that includes patient history and clinical findings, along with gross and microscopic images of different disease conditions. VM use in PBL and clinical case sessions can also aid in developing a multidisciplinary approach to attempt questions. This strategy could reinforce the essential concepts from other courses as well, possibly paving a path for both horizontal and vertical integration. Though this competency can be achieved by use of LM as well, VM makes it more interesting and easier. In the basic science curriculum, system-based practice is one of the most challenging competencies to teach and assess, as often students are inadequately exposed to patients in a hospital or clinical setting.[22] However, the United States Food and Drug Administration (USFDA) has recently approved the use of VM for diagnostic purposes.[23] Thus, VM can provide a modality that will help bridge the gap for students with inadequate clinical exposure.

There are numerous well-documented advantages of using VM for teaching. Significant benefits include high efficiency, easy accessibility, and cost reduction. With ample free online resources and websites hosting WSI over a cloud-based system, access is easy. Students can access these images at their convenience, even on their tablet computers and smartphones. Biolucida viewer and Recutclub are excellent online resources which provide access to an archive of clinical cases based on WSI.[24],[25] Efficiency is also increased as one faculty can manage learning sessions with the use of VM, which would have otherwise taken several faculty members to manage. This will lead to a reduction in faculty workload for conducting these activities. Several studies from other universities have shown a reduction of time spent in conducting laboratory sessions.[7],[26]

The transition from LM to VM for our university was a straightforward process, similar to various undergraduate medical universities.[27] VM use for teaching histopathology also reduced our ongoing expenditure. The implementation merely requires the acquisition of pre-prepared WSI run on a local network server as compared to maintenance of light microscopes along with large sets of fragile glass slides depicting similar pathological features. The only expenditure was to purchase the online slide box (IOWA Virtual Slide Box; around 1000 WSI) which is a very cheap option available for teaching use. The Aperio ImageScope software is available as a free download from the internet.[16]

Other advantages of VM are that students can easily navigate the images, highlight areas of interest, and create a thumbnail view or location boxes for tracking navigation. VM also wholly simulates the panning and zooming features of LM.

Furthermore, medical schools may want to transition to VM because traditional microscopes require adequate lighting, stage adjustments, and manual focusing. Glass slides fade over time, which will require replacement. However, if glass slides are converted to WSI, which is a one-time process, they can be backed-up on hard drives and memory clouds and repeatedly used for an indefinite period. The high cost of slide scanners and storage of images on a high end fast server is still a distant option for most pathology labs in India due to exorbitant costs. On contrary, acquisition of WSI for teaching purposes is a viable option and is already being used in medical schools worldwide.

In addition to its proven benefits in the academic setting, WSI for diagnostic purposes has been shown to have comparable accuracy and reliability to LM.[28] Researchers have found in their blinded, randomized study that there is a high concordance between VM and LM when making a diagnosis.[29],[30] Moreover, the WSI and VM system allows specialists from anywhere in the world to collaborate and consult with each other in making a diagnosis. Thus, early exposure to VM will prepare students to work efficiently with advanced patient health information systems, in which they will be able to view histopathology images and reports of patients. Recently, the USFDA has authorized the marketing of the Philips IntelliSite Pathology Solution (PIPS), which is the first WSI system for interpreting digital surgical pathology slides from biopsy tissue samples.[23] Thus, with the increasing use of VM for histopathology diagnosis, it is imperative that students become proficient in using these systems.

Despite convincing evidence of the benefits of VM use in an academic setting, a disadvantage is that complete transition from LM to VM may be difficult. Some medical schools may not have the technology that is required to implement this system. Another disadvantage that can result from a complete transition from LM to VM is that students will miss out on learning an essential skill of handling a light microscope and preparing glass slides.

   Conclusions Top

VM use has proven to be a practical solution for the challenges of teaching histopathology and has the potential to transform the process of both teaching and learning histopathology. The use of VM can also enhance the medical curriculum in a CBE system. Students can develop competencies primarily in medical knowledge along with professionalism, self-directed learning, and problem-solving and communication. It can also provide a challenging and motivating atmosphere for learning pathology. VM is one such facet that can provide an avenue to help accomplish these competencies in undergraduate medical education. In the future, VM use may become widespread and may even replace the traditional LM as a method to teach histopathology in undergraduate courses in medical schools. However, learning to prepare glass slides and operating a light microscope should not be neglected.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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Correspondence Address:
Samal Nauhria
Windsor University School of Medicine, P.O. Box 1621, Brighton's Estate, Cayon
St. Kitts and Nevis
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_241_18

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  [Table 1], [Table 2], [Table 3]

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