## 3 Results
On a scale of 1-5 (with 1 being \"not at all\" and 5 being \"very much\"), the mean values were above average for each question listed in Table 4. The SD values indicate a high variability in all responses, which may be due to the low sample size. Following the demonstration of the 3 DPMs, the sonographers indicated that their confidence, understanding, and ability to spatially visualise the PCI increased in proportion to the PCI complexity, as illustrated in Table 4 and Figures 2-4. \begin{table}
\begin{tabular}{l l l l} \hline
**Question:** & **Mean** & **SD** \\
**Have the 3 DPMs Improved Your.** & & **3.84** & 1.14 \\ \hline Confidence in assessing NCI with ultrasound & & 3.73 & 1.28 \\ \hline Confidence in assessing MCI with ultrasound & & 3.84 & 1.23 \\ \hline Confidence in assessing a VCI with ultrasound & & 4.36 & 0.89 \\ \hline Understanding of the structural relationship between the placenta and NCI & & 3.33 & 1.34 \\ \hline Understanding of the structural relationship between the placenta and MCI & & 3.82 & 1.26 \\ \hline Understanding of the structural relationship between the placenta and VCI & & 4.45 & 0.90 \\ \hline Ability to spatially visualise the placenta and NCI & & 3.64 & 1.41 \\ \hline Ability to spatially visualise the placenta and MCI & & 3.94 & 1.25 \\ \hline Ability to spatially visualise the placenta and VCI & & 4.39 & 1.00 \\ \hline \end{tabular}
\end{table} 
Table 4: Mean ratings of the 3 DPMs based on participants’ responses (n = 33). \begin{table}
\begin{tabular}{l l l l l l} \hline
**PCI Type** & \multicolumn{3}{c}{**Ranking 1 n (\%)**} & **Ranking 2 n (\%)** & **Ranking 3 n (\%)** & \(p\)**-Value** \\ \hline NCI & Image & 27 (81.8) & 3 (9.1) & 3 (9.1) & 0.348 \\ \hline  & Video & 3 (9.1) & 23 (69.7) & 7 (21.2) & 0.785 \\ \hline  & Model & 3 (9.1) & 7 (21.2) & 23 (69.7) & 0.862 \\ \hline MCI & Image & 26 (78.8) & 5 (15.2) & 2 (6.1) & 0.341 \\ \hline  & Video & 3 (9.1) & 24 (72.7) & 6 (18.2) & 0.824 \\ \hline  & Model & 4 (12.1) & 4 (12.1) & 25 (75.8) & 0.452 \\ \hline VCI & Image & 28 (84.8) & 2 (6.1) & 3 (9.1) & 0.483 \\ \hline  & Video & 0 & 29 (87.9) & 4 (12.1) & 0.492 \\ \hline  & Model & 5 (15.2) & 2 (6.1) & 26 (78.8) & 0.586 \\ \hline  & PCI: placental cord insertion. NCI: normal cord insertion, MCI: marginal cord insertion, VCI: velamentous cord insertion. & & & \\ \end{tabular}
\end{table} 
Table 3: Ranking for method of demonstration for each PCI type with \(p\)-values shown, (n = 33). Figure 3: Rating of the 3 DPMs in improving the understanding of the structural relationships between the PCI and placenta (%). The values 1–5 represent the Likert scale, while the numbers in the y-axis indicate the percentage of participants providing these scores. NCI: normal cord insertion, MCI: marginal cord insertion, VCI: velamentous cord insertion. Figure 2: Rating of the 3 DPMs in improving confidence in assessing the PCI (%). The values 1–5 represent the Likert scale, while the numbers in the y-axis indicate the percentage of participants providing these scores. NCI: normal cord insertion, MCI: marginal cord insertion, VCI: velamentous cord insertion. There was no significant association between a sonographer's years of experience and the 3 DPMs in terms of improving their confidence, understanding, or ability to spatially visualise the placenta and PCI (Table 5). Most sonographers indicated they felt the models of each PCI type would be useful in ultrasound education (Figure 5) with 75.8%, 84.8%, and 97% indicating the models of normal, marginal, and velamentous cord insertions, respectively, would be extremely useful. Participants were also asked how likely they would be to recommend the models as an educational device with 69.7%, 72.7%, and 81.8% indicating they would recommend normal, marginal, and velamentous cord insertion models, respectively (Figure 6). Figure 4: Rating of the 3 DPMs in improving ability to spatially visualise the placenta and PCI (%). 1–5 indicates Likert scale. NCI: normal cord insertion, MCI: marginal cord insertion, VCI: velamentous cord insertion.