On the added benefit of virtual anatomy for dissection‐based skills

Technological approaches deploying three‐dimensional visualization to integrate virtual anatomy are increasingly used to provide medical students with state‐of‐the‐art teaching. It is unclear to date to which extent virtual anatomy may help replace the dissection course. Medical students of Johannes Kepler University attend both a dissection and a virtual anatomy course. This virtual anatomy course is based on Cinematic Rendering and radiological imaging and teaches anatomy and pathology. This study aims to substantiate student benefits achieved from this merged teaching approach. Following their dissection course, 120 second‐year students took part in objective structured practical examinations (OSPE) conducted on human specimens prior to and following a course on Cinematic Rendering virtual anatomy. Likert‐based and open‐ended surveys were conducted to evaluate student perceptions of both courses and their utility. Virtual anatomy teaching was found to be unrelated to improvements in student's ability to identify anatomical structures in anatomical prosections, yielding only a 1.5% increase in the OSPE score. While the students rated the dissection course as being more important and impactful, the virtual anatomy course helped them display the learning content in a more comprehensible and clinically applicable way. It is likely that Cinematic Rendering‐based virtual anatomy affects knowledge gain in domains other than the recognition of anatomical structures in anatomical prosections. These findings underline students' preference for the pedagogic strategy of the dissection course and for blending this classical approach with novel developments like Cinematic Rendering, thus preparing future doctors for their clinical work.


INTRODUC TI ON
Anatomical dissection is a well-established and highly effective tool to teach human anatomy. 1,2 Despite various new and emerging methods becoming available to teach anatomy, dissection has remained the most appreciated teaching tool among anatomists, especially for three-dimensional (3D) understanding. 3 Recent studies confirm the importance of the dissection course as a mainstay in anatomical teaching. 4,5 A great benefit of dissection is that it integrates multiple senses to understand anatomical facts. 6 Further benefits students receive from anatomical dissection, include, but are not restricted to skill development, coping with stress, time management, learning strategies, and the ability to work in teams during the course. 7 In addition, it is a strategy that can assist learners in relating structure, function, and pathology. 8 During the global pandemic of Covid-19 in 2020, in-person teaching was largely restricted 9 ; digital learning resources like voice-over videos and web-based training approaches, which were previously only used as additional learning material, became increasingly important as an attempt to replace anatomical dissection. [10][11][12] Also, virtual 3D models became popular among many universities. 13 Although brought to the forefront by the pandemic, these techniques that enable distance learning, particularly for anatomy were already in existence; virtual anatomy is an umbrella term for teaching methods of gross (macroscopic) anatomy that are not based on anatomical specimens, atlases, or printed media such as books. This includes 3D visualization technologies and imaging methods such as plain radiography, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and angiography. 14 According to previous studies, an effective method for teaching gross anatomy combines both radiology and classical anatomy teaching such as anatomical dissection of human post-mortem tissues. [15][16][17] Integrating radiology education early into the curriculum stimulates students' interest in anatomy, helps them engage with medical imaging, and creates a clear connection between basic and clinical sciences. 16,[18][19][20][21] Orsbon et al. 22 showed that trained doctors are in favor of vertical integration of anatomy teaching.
Another important aspect of integrating radiology into anatomy teaching is that the human body and pathologies can be shown in situ or even in vivo, while anatomical specimens are limited to a postmortem state, which is potentially accompanied by spatial distortion due to the embalming and dissection processes. 15 Small-group radiology teaching was also shown to increase students' scores in multiple-choice questions on anatomy. 23 In contrast, however, imaging methods have been unable to replace the tactile experience while working with human specimens. 15

Three-dimensional visualization technologies
Advancements in computer technologies have led to the development of virtual tools to facilitate visualization in various medical disciplines. 24,25 For example, the photo-realistic 3D visualization technology Cinematic Rendering (Siemens Healthineers, Erlangen, Germany) has already been found to be useful for preoperative planning and diagnosis of visceral pathology. 26,27 Furthermore, students are becoming increasingly interested in using 3D visualization technology for their anatomy learning, which is reflected by the growing market offering 3D technologies for anatomy users. 28,29 In a meta-analysis, including 3D visualization technology in anatomy teaching was found to be more effective than including two-dimensional (2D) representations, thus resulting in higher user satisfaction. According to the findings, the gain in spatial comprehension was consistently superior. Regarding factual knowledge, the 3D visualization methods tended to be superior. 30

Creation of renderings
The following three steps form the basis of volume rendering methods for CT-or MRI-data sets: 1. Volume formation: First, the 3D volume is created from 2D data.
2. Classification: The visual characteristics are calculated for each voxel based on the properties of the tissue it represents.
3. Image projection: Finally, the voxels are projected on the volume in a user-selected orientation, this is how the pixels of the 3D image are created. 31

Visualizing imaging data sets using the Cinematic Rendering technology
Cinematic Rendering is a new and emerging technology. 32 It comprises a 3D post-processing software provided by Siemens Healthineers (Siemens Healthcare GmbH, Erlangen, Germany), and is characterized by photorealistic 3D visualization of CT and MRI data sets. 33,34 To animate the data sets and present them in a more realistic fashion, complex interactions between light and anatomical structures are taken into account. 35 Compared to conventional 3D visualization techniques, this leads to better spatial differentiation of neighboring anatomical structures. 36 The physical simulation of light diffusion is achieved by Monte Carlo integration, 37 which is also used in the film industry. In addition, the lighting conditions of a spherical panorama are applied to the data set. In contrast, in conventional volume rendering-each pixel receives only one ray of light, thus no details such as reflections and shadows can be displayed. 33

The benefits of Cinematic Rendering as a tool in gross anatomy education
In recent studies, students rated Cinematic Rendering to be useful in anatomy education. 38,39 Visualization, along with memorization and comprehension, is seen as one of the key components to gain anatomical knowledge. 40 Consequently, 3D visualization technology seems to be a beneficial tool as it was shown to be more effective for spatial comprehension than 2D images. 30 Furthermore, Cinematic Rendering was found to be superior to other 3D visualization technologies regarding differentiation of adjacent structures, and spatial distinction. 36 Therefore, Cinematic Rendering appears to provide certain benefits in the realm of virtual anatomy teaching.

Aims and hypotheses
The aim of this given study was to (1) determine whether virtual anatomy teaching can help improve student performance in identifying anatomical structures, (2) evaluate student opinions on the added value of virtual anatomy using Cinematic Rendering merged with classical anatomy teaching, and (3) correlate potential relationships between student performance and preferred teaching methods.
It has been hypothesized that Cinematic Rendering allows students to improve their ability to identify anatomical structures in human prosections.

Course details
Anatomy is a subject taught in the first and second year at the Medical Faculty of the Johannes Kepler University (JKU) in Linz (Austria). Anatomy teaching comprises courses on histology, embryology, neuroanatomy, and gross anatomy. For the latter, the following courses are held ( Figure 1).
In the first semester, 18 hours of lectures are spent on gross anatomy. Students are taught the anatomy of the musculoskeletal system, the cardiovascular system, head and neck, trunk, upper and lower limbs, and the peripheral nervous system. This course is held in face-to-face classes based on lectures, discussions, and elearning. At the end of the course, students are assessed by a written electronic examination. Parallel to this course, 9 hours of lectures and 39 hours of seminars on the topics of the dissection course are held.
In the second semester, a four-week dissection course is held at the Medical University of Graz (Austria) for JKU students. The provision of knowledge, technology, and dissection-based classes is regulated in a memorandum of understanding between both universities.
In 94 contact hours of lectures, the basics for the upcoming dissection sessions are taught. A total of 64 hours is spent on cadaverbased dissection and another 16 hours on self-directed learning.
Students are split into two groups of 60 to 70 and dissect 10 to 12 Thiel 41 or ethanol-glycerin 42  where Cinematic Rendering is presented on a wall-filling 8K-screen.
Students are provided with 3D active shutter glasses to follow the interactive presentations given by an experienced anatomist and radiologist, who navigates through the 3D Cinematic Rendering images using a controller (Figures 2 and 3).
This course also includes lectures from surgeons, who present their clinical cases, and video broadcasts from the operation theater.

Objective structured practical examination (OSPE), student evaluation, and qualitative data assessment
Second-year medical students of JKU who had already finished the dissection course were invited to participate in this study.

F I G U R E 2
The "medSPACE" of the Johannes Kepler University, in which human anatomy is taught using Cinematic Rendering presentations. The image shows an audience being presented the anatomy of the vessels of the abdominal region alongside with the topography of the kidneys. Five-point Likert scales were used for this purpose (1 = strongly agree to 5 = strongly disagree). This survey was designed by experienced anatomists and psychologists. Pilot testing and assessment took place prior to its use for the given study. This assessment was conducted following the completion of the last OSPE.
The Likert-Survey questions assessing either the dissection course or virtual anatomy were separated for validation analyses.
These groups did not include the questions assessing whether the course could be removed from the curriculum and whether the subject matter was overwhelming, as these questions assessed negative aspects, unlike the other Likert elements. Cronbach's alpha for the dissection course group was 0.67 and 0.78 for the virtual anatomy group, indicating acceptable to a good consistency. Kendall Tau-b is presented in the appendix.
In addition, student perceptions of the virtual anatomy and dissection courses were assessed using open-ended questions to gather qualitative data. These questions used were evaluated by the same team as above and an experienced radiologist: • How was your experience with virtual anatomy teaching using Cinematic Rendering?
• Where do you see the benefit for your clinical work and the clinical part of your medical education in virtual anatomy teaching using Cinematic Rendering?
• How was your experience with the dissection course?

Demographic information
A total of 120 medical students (n = 1 20; 72 females, 48 males) at the JKU who were in the third semester of their studies and had already finished their dissection course, participated in this study.  Table 1).

The dissection course was perceived as being the more important but overwhelming part of anatomy teaching
The Likert survey indicated that the importance of the dissection course was rated significantly higher than that of virtual anatomy.
Moreover, the dissection course was significantly more likely to be rated as the best way to learn human anatomy. The increase in knowledge was rated as high in both courses with no significant difference. Moreover, students felt significantly less likely to be overwhelmed by the scope of the subject matter in virtual anatomy when compared to the dissection course. Students strongly declined the possibility to remove either of the courses from the curriculum ( Table 2).

Dissection motivates students to active learning; virtual anatomy is rated as easier to understand
According to the Likert survey, the students were significantly more likely to prepare and review the learning content parallel to the dissection course than in virtual anatomy. Moreover, virtual anatomy was rated to be significantly more likely to stimulate interest in anatomy, while both courses achieved good results in this question.
Presentation of the subject matter was ranked significantly more understandable in virtual anatomy than in the dissection course.
Additionally, students felt significantly better prepared for the clinical part of their study in virtual anatomy than in the dissection course ( Figure 5 and Table 3).

To undergraduate medical students Cinematic Rendering is interesting but offers no replacement for the dissection course
According to the Likert survey, students rate Cinematic Rendering as an interesting tool, that is easy to follow and helps to supplement anatomical knowledge. It was also rated as incapable of fully replacing the dissection course ( Figure 6 and Table 4).

Examination outcomes positively correlated with student attitudes that dissection is indispensable
Correlation analyses of the data from 81 students revealed that those students perceiving virtual anatomy as helpful to engage TA B L E 1 Pre-and post-virtual anatomy teaching results in objective structured practical examinations.

Students value the visualization provided in virtual anatomy and the haptic experience provided in the dissection course
Most of the students participating in the qualitative assessment (75%) mentioned that the virtual anatomy course is beneficial for TA B L E 2 Survey results from medical students comparing virtual anatomy and dissection course.

Virtual anatomy Mean (±SD) Dissection course Mean (±SD)
… is the most important course in anatomical teaching for learning and understanding 2.7 (±1.0) 1.9 (±0.9) The best teaching tool for anatomy is … 2. Note: Student perceptions of dissection and virtual anatomy course. 120 students responded on the five-point Likert-type scale with 1 being "strongly agree" and 5 being "strongly disagree". Results are shown as mean ± standard deviation (SD).

F I G U R E 5 Student perceptions of dissection and virtual anatomy course.
A total of 120 students responded on a 5-point Likert-type scale with 1 being "strongly agree" and 5 being "strongly disagree". Boxes indicate the mean values. Whiskers indicate standard deviation.
Blue boxes indicate the dissection course, red boxes indicate the virtual anatomy course. Significant differences are presented with the level of significance of a p < 0.001.
anatomy visualization purposes. Some students described that the proportions and spatial relationships can be shown particularly well, and that viewing anatomy from all perspectives offers benefits over dissection-based anatomy. The students found that the virtual anatomy course and the clinical lectures prepared them well for the clinical part of their studies and that a connection was established between anatomy and radiology and thus between preclinical and clinical teaching. The fact that the recognition of common pathologies in imaging is taught early in the curriculum was also noted as positive. One student mentioned that he is sure he will be able to implement the gained knowledge in the operation theater. For the dissection course, the haptic experience was mentioned as beneficial by 33% of the participants. For

DISCUSS ION
A broad range of contemporary anatomy teaching methods has become available in recent years. 45,46 Some are only used at a few universities, 47,48 and others worldwide. 49 There is a strong consensus that contemporary teaching technologies present powerful options to add to the standard anatomy curriculum. 4,50 Students appear to prefer learning with 3D tools over traditional methods to some extent. 51 The given study aimed to substantiate the added benefit of Cinematic TA B L E 3 Survey results from medical students comparing virtual anatomy and dissection course.

Virtual anatomy Mean (±SD) Dissection course Mean (±SD)
In …, I regularly prepared and repeated the learning content 3.3 (±1. Note: Student perceptions of dissection and virtual anatomy course. 120 students responded on a five-point Likert-type scale with 1 being "strongly agree" and 5 being "strongly disagree". Results are shown as mean ± standard deviation (SD).

F I G U R E 6 Student perceptions of Cinematic
Rendering-based anatomy. 120 students responded on a five-point Likert-type scale with 1 being "strongly agree" and 5 being "strongly disagree". Boxes indicate the mean values. Whiskers indicate standard deviation.

TA B L E 4
Survey results from medical students rating Cinematic Rendering.

Mean (±SD)
Cinematic Rendering-based anatomy is interesting to me 1. Note: Student perceptions of Cinematic Rendering. 120 students responded on a five-point Likert-type scale with 1 being "strongly agree" and 5 being "strongly disagree". Results are shown as mean ± standard deviation (SD).
Rendering-based virtual anatomy teaching on students' dissectionbased anatomy knowledge and to evaluate students' opinion on the courses. The virtual anatomy course at the JKU deployed a blended learning approach, utilizing radiological imaging, digital volume rendering technology Cinematic Rendering, lectures held by clinicians, and live streams delivered by anatomists from the dissection room.
This novel approach to teaching anatomy makes it possible to learn under a more integrated and encompassing approach. Students participated in a full-scale dissection course in their second semester, followed by courses in system-based integrated anatomy teaching in their third and fourth semesters. This philosophy aims at repeating, supplementing, and consolidating what has been taught in the dissection course and to create a connection to the clinical sciences.
This study aimed at assessing student knowledge and their ability to identify structures in OSPEs conducted on human prosections prior to and following one semester of virtual anatomy teaching.
Further objectives were to compare and capture student perceptions of the virtual anatomy course, the dissection course, and of Cinematic Rendering. Potential relationships between student performance and their preferred teaching methods were determined in correlation analyses.

Virtual anatomy teaching appeared to be unrelated to improved knowledge in prosection-based anatomyother learning domains may be affected
In the OSPEs assessing anatomy knowledge in prosections, students were not found to have improved their results on a significant level.
In consequence, additional teaching based on Cinematic Rendering  48 Students receiving additional teaching on radiology imaging using CT scans of the specimens on the Anatomage Table (Anatomage Inc., Silicon Valley, CA) parallel to their dissection, performed better in multiple-choice questions on basic anatomy than those with dissection alone. 49 The Anatomage

Dissection-based anatomy remains an indispensable teaching and learning tool in gross anatomy, while virtual anatomy offers a beneficial adjunct to integrate anatomy knowledge with clinical application
In the given assessment, the importance of the dissection course was rated higher than the importance of virtual anatomy teaching.
This finding helps substantiate the results from previous studies showing that students consider contemporary (virtual) techniques an adjunct but not a replacement for dissection-based anatomy. 53 Students and anatomists likewise stated that the dissection course should keep its position as the key teaching tool in anatomy. 3,5 This finding is confirmed both quantitatively in the given study, and further underlined by student comments: "The dissection course is essential to really understand anatomy." It must however be kept in mind that no single teaching tool combines all curriculum requirements for future doctors 8 and many anatomists support the integration of diverse and system-based teaching. 54 Using virtual anatomy, the participants of this study stated that the subject matter was presented in a comprehensible fashion, whereas they felt overwhelmed in the dissection course.
Moro et al. 55 confirmed that students view virtual anatomy as a tool that helps them understand anatomy. A recent study also shows that students feel more stress and fear before dissection than before virtual anatomy 52 ; exposure to stress is inevitable for future physicians; hence, it might be beneficial to learn to deal with it early on. The appreciation for this becomes apparent in this student's comment: "In the dissection course I learned how to deal with stress."

A combination of dissection-based and virtual anatomy may help form an undergraduate curriculum of the future
The Likert elements assessing whether the dissection course or virtual anatomy should be removed from the curriculum indicated that both courses were highly valued by the students to achieve their learning objectives, and thus should not be removed from the present curriculum. A small number of American institutions, which had removed the dissection course from their curriculum almost completely resumed or re-established aspects of the dissection experience. 56 Only a few universities have discontinued using dissection as a principal method of anatomy teaching. [57][58][59] A recently published study warns that anatomy lectures will perish unless the most effective pedagogical methods and interactive learning are integrated. 60 Therefore, a curriculum combining radiology and classical anatomy teaching methods 15 with modern 3D visualization techniques may be a complementary approach.

Students spend less time preparing for virtual anatomy and rated it to be more stimulating regarding interest in anatomy
Students prepared and reviewed the learning content more regularly in the dissection course than in the virtual anatomy course as seen by the five-point Likert questionnaire ( Figure 5). This may be partly ascribed to the fact that the dissection course is one of the JKU students' first exposure to anatomy. Throughout the four-week dissection course, students spent more time dealing with the subject matter outside the dissection room which likely helped them to consolidate gained knowledge and go deeper into the subject. Both the dissection course and virtual anatomy were found to stimulate interest in anatomy, with virtual anatomy reaching a better result than dissection. Triepels et al. 29 assessed medical students' perceptions of anatomy and reported that 55.6% did not find anatomy to be an attractive subject in the sense of arousing their interest. It must be critically noted that the assessment of the quality of teaching is significantly influenced by the curriculum, curricular framework conditions, and the lecturers themselves.

Students perceive virtual anatomy to be an excellent preparation for their clinical phase
The combination of anatomy with pathology offered in this course on virtual anatomy allowed students to understand the importance of anatomy by pointing out clinical relevance, which was sparsely the case in old teaching curricula. 61 Students commented: "I find it helpful and beneficial that medical students can relate to the clinical implications early in their training through this curriculum. The complicated field of radiology is brought closer to the students with exciting case studies and interactive work" and "Virtual anatomy helped us gain better orientation for surgery and profound basic knowledge in the evaluation of CT, MRI and plain radiography." Another benefit of virtual anatomy indicated by the survey is that students feel well-prepared for their clinical phase of medical education. Previous studies demonstrated that students consider the "clinical utility" of both dissection and virtual anatomy as high. 52 The dissection course on the one hand is the first contact with basic surgical instruments for most medical students, and they develop professional competence in dealing with stress, time management skills, learning strategies, and working in teams. On the other hand, virtual anatomy allows students to consolidate anatomy knowledge in a 3D environment, without being bound to the dissection room. 7

Students rate Cinematic Rendering as a highly beneficial method for anatomy teaching
The digital volume rendering technology "Cinematic Rendering" is a popular aspect of the virtual anatomy course at the JKU. Although Cinematic Rendering is deemed by the students as an interesting tool, easy to follow, and helps supplement anatomical knowledge, it is still found to be incapable of fully replacing the dissection course.
The positive results concerning Cinematic Rendering confirm the results of previous studies in which students rated this technology as highly helpful for learning anatomy. 38 While the effect on student knowledge still must be confirmed, student perception indicates that it is a beneficial tool in anatomy teaching.

Preparing and repeating subject matter in virtual anatomy led to higher improvement in the objective structured practical examinations
Correlation analyses demonstrated that there were different learning types among the participants. This might help contextualize to some extent why no improvement in OSPEs could be seen. Students who stated that the dissection course was indispensable to their curriculum could improve their performance in the OSPEs. Those who did not prepare or repeat the learning materials, in consequence, did not benefit from the course, respectively, achieved negative results, which offset the positive effect of the other group of learners.

Limitations of the study
Considering the results of the OSPEs, it must be kept in mind that the here assessed students have not had direct exposure to anatomy dissections for more than 6 months prior to the OSPEs, that the exposure to video streams was timely limited, and that there was a difference in the teaching style used in the dissection course and virtual anatomy. In addition, the OSPE questionnaire was designed to assess primarily the learning outcomes of the dissection course, whereas the learning outcomes in virtual anatomy were partly deviant, especially regarding pathological findings. Future research should try and determine the effects of virtual anatomy teaching using other examination modalities, e.g., recognizing structures in CT and MR images.

CON CLUS IONS
Cinematic Rendering seems to be a beneficial tool in virtual anatomy to supplement conventional dissection-based anatomy training.
This study shows that students are in favor of additional anatomy teaching using Cinematic Rendering and that they feel well prepared