Table 1.

The manufacturing process. Summary of the steps of our manufacturing process for vascular 3D printing with clear and flexible resin, used in this case series

Step	Description
1. CT scan	Standard protocol CT angiography in arterial phase with axial reconstructions in 1-mm slice thickness Note that a larger slice thickness will cause a loss of detail and the formation of steps in the vascular models
2. Segmentation	ImageJ (open-source software) was used for segmentation and the included 3D-Viewer plugin for creating surface models in form of STL files Note that any segmentation and 3D-modelling software can be used, but has to be focused on a high grade of detail of the procedure-relevant vascular system
3. 3D modeling	Blender (open-source software) was used for digital post-processing (removing residual non-vascular structures) and creating the vessel walls (1 mm) for each STL file
4. 3D printing	PreForm (included software, Formlabs) was used for 3D printing at a resolution of 0.1 mm and with automatic generation of external supports at a density of 0.8 and touching point size of 0.4 mm Note that it is important that internal (intraluminal) support structures are deactivated, because they cannot be removed from the inside of small vessels afterward
5. Cleaning	The printed models were at first cleaned automatically for 10 min in isopropanol (Form Wash, Formlabs) and second by hand using isopropanol in a syringe to flush and fully clean the small structures Note that it is important that all vessels are free from residual resin to prevent permanent vessel blockages from final curing in ultraviolet light (step 7)
6. Support removal	Support structures were carefully, but easily removed by hand, right after cleaning Note that support structures are much easier and safer to remove before curing (step 7)
7. Curing	The models were finally cured in ultraviolet light for 10 min with 40 °C (Form Cure, Formlabs) Note that the models are ready to be used for simulation immediately after curing