# Clinical Validation of a New Enhanced Stent Imaging Method
## 3 Results
### Quantitative Analysis  
Out of 93 lesions, reliable QCA analysis could be performed on the final PCI result in 90 lesions. Foreshortening or the overlap of branches precluded the analysis in five lesions. The mean stent diameter on QCA after stent implantation was 2.74 \(\pm\) 0.53 mm and differed significantly from the predicted chart diameter (\(p<\) 0.05). On average, the predicted chart diameter upon stent implantation was 0.44 \(\pm\) 0.44 mm larger than the mean stent diameter on QCA (95% CI; 0.34 to 0.53). This was also found upon comparison of mean stent diameter by QCA and maximal achieved post-dilation balloon diameter (\(p<\) 0.001). The stents diameters found by QCA tended to be 0.74 \(\pm\) 0.48 mm smaller than  
Figure 3: Linear regression between SNRs of StentBoost and StentEnhancer on 53 different frames. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & **SE** & **SB** & **Kendall Coefficient** \\ \hline \multirow{4}{*}{**S**} & **Stent underexpansion (\%)** & 71.5 & 73.9 & 61 \\  & **Calcifications (\%)** & 64.0 & 43.8 & 58 \\  & **Stent underexpansion (\%)** & 47.0 & 47.0 & 92 \\  & **Calcifications (\%)** & 63.9 & 62.7 & 91 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of rates of calcifications and underexpansion by SE and SB. the maximal achieved balloon diameter upon post-dilation (95% CI; 0.62 to 0.84). The remaining stents could not be quantified due to vessel overlapping. A quantitative SE analysis could be performed in more stents (n = 91) using both orthogonal views after deployment of the stent and following post-dilation (Figure 4). The mean stent diameter post-implantation was 2.96 \(\pm\) 0.45 mm (90% of predicted chart diameter) which was statistically different from the expected chart diameter (_p_ < 0.001). The expected chart diameter was on average 0.31 \(\pm\) 0.30 mm larger than the SE diameter (95% CI; 0.25 to 0.38). There was no statistically significant difference between the measured mean stent diameters and the measured diameters at the maximal stent underexpansion point between the two orthogonal views upon implantation (2.95 \(\pm\) 0.46 mm vs. 2.95 \(\pm\) 0.49 mm and 2.39 \(\pm\) 0.46 mm vs. 2.44 \(\pm\) 0.47 mm, respectively; \(p\) > 0.05). The mean stent diameter after post-dilation by SE was 3.13 \(\pm\) 0.49 mm (84% of predicted balloon diameter) and was, on average, 0.47 \(\pm\) 0.31 mm smaller than the balloon diameter (95% CI; 0.39 to 0.56). The mean maximal stent underexpansion upon deployment was 19 \(\pm\) 9% and 16 \(\pm\) 7% after post-dilation. There was no statistically significant difference in the measured mean stent diameters between the two orthogonal views after post-dilation (3.11 \(\pm\) 0.48 mm vs. 3.18 \(\pm\) 0.55 mm; \(p\) > 0.05); however, a statistically significant difference was noted for the measured diameter at the site of maximal stent underexpansion point between the two views after post-dilation (2.58 \(\pm\) 0.52 mm vs. 2.69 \(\pm\) 0.52; \(p\) = 0.004). The achieved mean diameter by SE after post-dilation was more in line with the expected chart diameter upon implantation with a mean difference of 0.13 \(\pm\) 0.32 mm (95% CI; 0.04 to 0.21). A statistically significant diameter gain of 0.23 \(\pm\) 0.23 mm was noted at the site of maximal stent underexpansion after balloon post-dilation was noted upon comparison of mean minimal stent diameters upon implantation and after post-dilation (2.41 \(\pm\) 0.44 mm vs. 2.63 \(\pm\) 0.49 mm, respectively; \(p\) < 0.001). The detailed quantitative analysis results can be found in Table 6. The mean stent diameters after stent deployment by SE were, on average, 0.41 \(\pm\) 0.44 mm [95% CI; 0.06 to 0.23] larger than the mean stent diameters by QCA (_p_ < 0.05) and were 0.32 \(\pm\) 0.38 mm [95% CI; 0.05 to 0.22] larger after post-dilation (_p_ < 0.05).