# Volumetric Analysis of Aortic Changes after TEVAR Using Three-Dimensional Virtual Modeling
## 3 Results
When evaluating the ROC curve analysis for the net volume change of the descending thoracic aorta, the cut-off point to predict TEVAR-related complications was 40.4 mL (AUC of 0.906, sensibility of 0.750, and specificity of 0.938, \(p\) = 0.001) (Figure 5). \begin{table}
\begin{tabular}{l c c c c c c} \hline  & \multicolumn{2}{c}{**TEVAR-Related**} & \multicolumn{2}{c}{**No TEVAR-Related**} & \multicolumn{2}{c}{**Complications vs. No**} \\  & \multicolumn{2}{c}{**Complications**} & \multicolumn{2}{c}{**Complications**} & \multicolumn{2}{c}{**Complications**} \\  & **(_n_ = 8)** & & **(_n_ = 16)** & & **Complications** \\ \hline \multirow{2}{*}{**Diameter Change**} & **Net** & **Relative** & **Net** & **Relative** & **Net** & \\  & **(mm)** & **(\%)** & **(mm)** & **(\%)** & **(_p_)** & **Relative** (_p_)** \\ \hline Proximal Neck (1) & 2.5 \(\pm\) 3.5 & 5.7 \(\pm\) 8.0 & 1.0 \(\pm\) 1.7 & 2.8 \(\pm\) 5.0 & n.s. & n.s. \\ Proximal Landing Zone (2) & 0.1 \(\pm\) 2.9 & 0.1 \(\pm\) 7.6 & 1.1 \(\pm\) 1.7 & 3.1 \(\pm\) 4.5 & n.s. & n.s. \\ Aneurysm (3) & 1.5 \(\pm\) 6.5 & 2.6 \(\pm\) 9.5 & \(-\)2.3 \(\pm\) 9.0 & \(-\)2.4 \(\pm\) 12.4 & n.s. & n.s. \\ Distal Landing Zone (4) & 4.3 \(\pm\) 8.4 & 10.4 \(\pm\) 18.6 & 0.2 \(\pm\) 3.2 & 0.9 \(\pm\) 8.6 & 0.049 & 0.048 \\ Distal Neck (5) & 3.4 \(\pm\) 11.3 & 8.9 \(\pm\) 25.3 & 0.5 \(\pm\) 2.4 & 2.1 \(\pm\) 6.7 & n.s. & n.s. \\ \hline \multirow{2}{*}{**Volume Change**} & **Net (mL)** & **Relative** & **Net (mL)** & **Relative** & **Net** & **Relative** (_p_)** \\ \hline Proximal Neck (1) & 6 \(\pm\) 1 & 26 \(\pm\) 31 & 2 \(\pm\) 1 & 8 \(\pm\) 4 & 0.001 & n.s. \\ Proximal Landing Zone (2) & 18 \(\pm\) 23 & 24 \(\pm\) 22 & 4 \(\pm\) 4 & 14 \(\pm\) 11 & n.s. & n.s. \\ Aneurysm (3) & 13 \(\pm\) 33 & 5 \(\pm\) 16 & \(-\)21 \(\pm\) 48 & \(-\)4 \(\pm\) 24 & 0.043 & n.s. \\ Distal Landing Zone (4) & 17 \(\pm\) 15 & 42 \(\pm\) 51 & 3 \(\pm\) 12 & 17 \(\pm\) 21 & 0.022 & n.s. \\ Distal Neck (5) & 22 \(\pm\) 23 & 72 \(\pm\) 110 & 2 \(\pm\) 8 & 5 \(\pm\) 16 & 0.030 & n.s. \\ Descending Thoracic Aorta (1, 2, 3, 4, 5) & 55 \(\pm\) 25 & 10 \(\pm\) 5 & \(-\)11 \(\pm\) 51 & 1 \(\pm\) 16 & 0.001 & 0.030 \\ \hline \end{tabular}
\end{table} 
Table 3: Diameter and volume analyses of the descending aorta after TEVAR related to subsequent complications. Both net (mm and mL) and relative (%) diameter and volume changes are reported for each segment of the descending aorta and for both groups. n.s. = not significant. Relative changes in the aortic volumes were also evaluated: only the global descending thoracic aortic volumes were significantly different between the two groups, with a 10 \(\pm\) 5% increase in the complication group and a 1 \(\pm\) 16% increase in the no-complication group (\(p\) = 0.030). The results of the ROC curve analysis for all diameters and volumes considered in the study are reported in Table 4.  
Figure 4: Example of a patient case analyzed by both methods: the conventional manual measurement from CTA imaging using MPR reconstructions orthogonal to aortic flow axis (**A**) and the new volumetric analysis (**B**), both performed at discharge and at the 12 month follow-up (FU) after TEVAR. (1) Proximal Neck; (2) Proximal Landing Zone; (3) Aneurysm; (4) Distal Landing Zone; (5) Distal Neck.