## 4 Discussion
As supported by our participants' responses, assessment of the PCI with ultrasound becomes more difficult with increasing complexity of the PCI, with an NCI being the most straightforward to visualise, and a VCI, due to its intricate anatomy, the most problematic to assess. [PERSON] et al. investigated the effect a 3 DPM of an orbit had on optometry students' education. The response of their participants was extremely positive, with the students indicating the model enhanced their ability to spatially visualise anatomical relationships, preferring the 3D models over traditional resources [4]. In the present study, most participants indicated the 3 DPMs would be beneficial in ultrasound education, increasing their confidence in assessment and spatial awareness of the PCI. Interestingly, statistical significance was not achieved when comparing these responses and years of experience, suggesting the 3 DPMs may be beneficial for sonographers with varying levels of practice. In their literature review, [PERSON] et al. found that 14 of 16 studies included in their review demonstrated that 3D modelling applications enhanced student education in ultrasound [33]. [PERSON] et al. showed that 3D models enhanced the understanding of and contributed significantly to anatomical education [34]. Interestingly, a study by [PERSON] et al. that evaluated the educational value of 3 DPMs, 3D images, and 2D images in assessing the ventricular system of the brain showed that not only did their participants rate their 3 DPMs higher than 3D images, but the models distinctly increased interest and enthusiasm among the students in their research [37]. Our findings, in conjunction with the current literature, support a positive role for 3 DPMs in ultrasound education. The free-text section of our questionnaire introduced new concepts for the use of 3D models in obstetric ultrasound education with two participants suggesting 3 DPMs of placental location and placental developmental variation would be beneficial. Our 3 DPMs could also provide enhanced patient understanding of placental and PCI anatomy and pathology. In 2022, [PERSON] et al. explored the concept of virtual reality (VR) in education of congenital heart disease with reported comparable benefits of 3 DPMs and VR models [24]. VR was preferred over 3 DPMs in a 2023 study by [PERSON] et al. [38]. As a future direction, it would be interesting to investigate the role of VR models in ultrasound education of the PCI. Long-term retention studies would also be prudent. As with all advancements in medical education, cost and feasibility must be considered when assessing the practicality of introducing 3 DPMs into ultrasound education. Three-dimensional printing technology is being used increasingly in medical and educational applications, with manufacturing costs varying greatly. The current literature describes decreasing costs [4; 7; 18]; however, the expenditure is relative to the model being created and the materials used. Perhaps the most significant cost is time, with the printing process sometimes taking days to complete. In our study, the print time for the individual components of the models ranged from 1.0 to 28.5 h, according to the size of the part (Supplementary Table S5), with a total cost of approximately AUD 50 per model, inclusive of materials and printing, making our models an affordable and readily accessible adjunct to ultrasound education. A further consideration is receipt of approval of the 3 DPMs from educational facilities. We would like to acknowledge some limitations of our study. As a small cohort from a single private radiology practice in Western Australia was recruited through convenience sampling, our results may not be representative of the entire population of sonographers employed at this practice or indeed sonographers employed by other ultrasound facilities.