## 3 Results
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Intra- and interobserver analysis of the hemodynamic parameters demonstrated a good reproducibility in the validation cohort for normalized flow displacement and flow jet angle (LoA \(\leq\)4.8% and \(\leq\)8.7\({}^{\circ}\) respectively, COV = 16-32%, r = 0.70-0.92, ICC = 0.80-0.94), an excellent reproducibility for vorticity norm (LoA \(\leq\)2779 s\({}^{-1}\cdot\)mL\({}^{-1}\), COV = 3-10%, r = 0.96-1.00, ICC = 0.96-1.00), and a very good reproducibility for absolute WSS\({}_{\rm mag}\), WSS\({}_{\rm ax}\), WSS\({}_{\rm cir}\), WSS\({}_{\rm angle}\), absolute helicity and volumes with increased absolute LNH (LoA \(\leq\)242 mPa, \(\leq\)244 mPa, \(\leq\)103 mPa, \(\leq\)8.9\({}^{\circ}\), \(\leq\)631 m\(\cdot\)s\({}^{-2}\cdot\)mL\({}^{-1}\) and \(\leq\)8.4 mL, respectively; COV = 3-26%, r = 0.86-1.00, ICC = 0.86-1.00). See Supplementary Materials Figures S1-S9 for the corresponding Bland–Altman plots. These plots demonstrated no striking dependency of the measured differences relative to the mean for the analyses and hemodynamic parameters. Intra- and interobserver analysis of the morphologic parameters demonstrated a very good reproducibility in the validation cohort for volume and centerline length (LoA \(\leq\)15.7 mL and \(\leq\)12.2 mm, respectively; COV = 8-22%, r = 0.89-0.98, ICC = 0.90-0.98), and an excellent reproducibility for diameter (LoA \(\leq\)5.0 mm, COV = 3-7%, r = 0.98-0.99, ICC = 0.96-0.99) and a good reproducibility for curvature radius (LoA \(\leq\)46.4 mm, COV = 21-35%, r = 0.72-0.87, ICC = 0.90-0.92). See Supplementary Materials Figures S10-S13 for the corresponding Bland–Altman plots. These plots demonstrated no dependency of the measured differences relative to the mean for most analyses and morphologic parameters, except for the maximal diameter, which had a slightly increasing difference relative to the mean for the interobserver analyses. The intra- and interobserver reproducibility results per anatomical segment are presented in Supplementary Materials Tables S3 and S4, respectively. The intra- and interobserver analysis showed for the validation cohort a similar reproducibility for most morphologic and hemodynamic parameters per segment. However, the reproducibility was slightly decreased within the aortic root for several parameters (i.e., flow displacement, WSS\({}_{\rm mag}\), WSS\({}_{\rm ax}\), absolute helicity, volumes with increased absolute LNH, aortic segment volume, centerline length, and curvature radius). Furthermore, the reproducibility of the maximal diameter was slightly decreased within the proximal part of the aorta (i.e., the aortic root, proximal and distal ascending aorta) compared to the other anatomical segments further distally to the ascending aorta (intraobserver LoA \(\leq\)2.7 and \(\leq\)1.8 mm; interobserver LoA \(\leq\)7.6 and \(\leq\)3.3 mm, respectively). Moreover, the reproducibility of WSS\({}_{\rm angle}\) was slightly decreased within the proximal and distal descending aorta. Figure 3: Aortic segments and hemodynamic parameters. Example of a patient (male, 71 years old) with an ascending aorta aneurysm with a diameter of 48 mm. (**A**) Anatomical segments with centerline (black color) and flow displacement line (blue color). (**B**) Vorticity norm. (**C**) Absolute helicity. Positive and negative magnitudes indicate a clockwise and anti-clockwise rotation, respectively. (**D**) Wall shear stress magnitude. (**E**) Axial wall shear stress. (**F**) Circumferential wall shear stress. Abbreviations: AoR—aortic root, pAA—proximal ascending aorta, dAA—distal ascending aorta, AoA—aortic arch, pDA—proximal descending aorta, dDA—distal descending aorta, and WSS—wall shear stress. Compared to the training cohort, the validation cohort demonstrated reduced LoA over all analyses for morphologic and hemodynamic parameters (LoA\({}_{\text{diff}}=-12\) [\(-26\)-\(3\)]%). This improvement was more evident for the morphologic parameters compared to the hemodynamic parameters (LoA\({}_{\text{diff}}=-20\) [\(-41\)--\(6\)]% and \(-9\) [\(-21\)-\(5\)]%, respectively).