"Visualization matters" - stereoscopic visualization of 3D graphic neuroanatomic models through AnaVu enhances basic recall and radiologic anatomy learning when compared with monoscopy

Abstract

Background: The authors had previously developed AnaVu, a low-resource 3D visualization tool for stereoscopic/monoscopic projection of 3D models generated from pre-segmented MRI neuroimaging data. However, its utility in neuroanatomical education compared to conventional methods (specifically whether the stereoscopic or monoscopic mode is more effective) is still unclear.

Methods: A three-limb randomized controlled trial was designed. A sample (n = 152) from the 2022 cohort of MBBS students at Government Medical College, Thiruvananthapuram (GMCT), was randomly selected from those who gave informed consent. After a one-hour introductory lecture on brainstem anatomy and a dissection session, students were randomized to three groups (S - Stereo; M - Mono and C - Control). S was given a 20-min demonstration on the brainstem lesson module in AnaVu in stereoscopic mode. M was given the same demonstration, but in monoscopic mode. The C group was taught using white-board drawn diagrams. Pre-intervention and post-intervention tests for four domains (basic recall, analytical, radiological anatomy and diagram-based questions) were conducted before and after the intervention. Cognitive loads were measured using a pre-validated tool. The groups were then swapped -S→ M, M →S and C→S, and they were asked to compare the modes.

Results: For basic recall questions, there was a statistically significant increase in the pre/post-intervention score difference of the S group when compared to the M group [p = 0.03; post hoc analysis, Bonferroni corrections applied] and the C group [p = 0.001; ANOVA test; post hoc analysis, Bonferroni corrections applied]. For radiological anatomy questions, the difference was significantly higher for S compared to C [p < 0.001; ANOVA test; post hoc analysis, Bonferroni corrections applied]. Cognitive load scores showed increased mean germane load for S (33.28 ± 5.35) and M (32.80 ± 7.91) compared with C (28.18 ± 8.17). Subjective feedbacks showed general advantage for S and M compared to C. Out of the S and M swap cohorts, 79/102 preferred S, 13/102 preferred M, and 6/102 preferred both.

Conclusions: AnaVu tool seems to be effective for learning neuroanatomy. The specific advantage seen when taught with stereoscopy in basic recall and radiological anatomy learning shows the importance of how visualization mode influences neuroanatomy learning. Since both S and M are preferred in subjective feedbacks, these results have implications in choosing methods (stereoscopic - needs 3D projectors; monoscopic - needs web based or hand-held devices) to scale AnaVu for anatomy teaching in medical colleges in India. Since stereoscopic projection is technically novel and cost considerations are slightly higher compared to monoscopic projection, the specific advantages and disadvantages of each are relevant in the Indian medical education scenario.

Keywords: Anatomical visualization; Anatomy education; Computer assisted learning; Monoscopic projection; Neuroanatomy; Spatial learning; Stereoscopic projection; Technology enhanced learning.

Fig. 1

Hardware of AnaVu. a Showing the dual output through HDMI from the CPU used for the AnaVu software system. b Showing the two projectors stacked one above the other, mounted within a projector cage. Polarization filters are also seen in front of the projectors. c Showing the silver screen used for the stereoscopic projection

Fig. 2

Screenshots from AnaVu user interface. a Shows the graphic user interface of AnaVu, which consists of 3 main vertical panels. The basal ganglia and the ventricles are visualized in the middle and right panels. Left panel shows the ‘buttons’ and controls for selecting lessons, structures, modifying opacity, and selecting monoscopic or stereoscopic visualisation modes. Middle panel shows the 3D viewport for 3D image demonstration. Right panel shows the three canonical 2D sections (axial, coronal, and sagittal sections of T1-MRI images) in that order from top to bottom, and the 2D sections of the 3D model (shown in the middle panel) colored correspondingly. These sections are scrollable by cursor. b Shows the right globus pallidus (pallidum) being selected when the label pops up

Fig. 3

Figure panel showing the functionalities of AnaVu. a Showing a 3D right antero-lateral view of the brainstem and spinal cord along with its different parts highlighted using distinct colors. b Showing an MRI of the axial section of the brainstem at the level of midbrain in the central panel with the 3D image of the same in the right panel. c Showing a 3D postero-supero-lateral view of the midbrain and pons. Better visualisation of the internal structures has been ensured by the reduction of opacity of the gross framework of midbrain. d Showing the 3D posterior view of the pons and medulla. Opacity of the part of pons and medulla has been reduced to show the internal structures. (The above pictures are screenshots from AnaVu. All labellings in this figure have been made using Adobe Photoshop)

Fig. 4

Number of questions of various domains (indicated as colors) at different Modified Bloom’s (MB) Taxonomy (consensus between two authors)

Fig. 5

Flow diagram depicting the sequence of the current study protocol. S, stereoscopy; M, monoscopy; C, control. Weighing scales at the bottom indicates that those students were allowed to compare the S to M (limb 1); M to S (limb 2); and C to S (limb 3) and tell what they preferred in the survey questionnaire that was given

Fig. 6

Hybrid table showing different interventions. The second column of the panel contains the photographs -a,b and c from sessions that were held for the three groups – S,M and C respectively

Fig. 7

Graphical representation of the mean values of the 5-point Likert scale responses to statements as part of subjective feedback. Bars—Purple for Stereo, Blue for Mono, and Green for Control—show the mean values. Error bars are also shown (± SD). The statements with *Only S had statistically significant difference from C; **Both S and M had statistically significant difference