I am trying to extract only the arteries from brain CT-Angiography. I tried a few things (Grow from seeds, vessel segmentation module etc. ) but nothing seems to work. Even if I could only get all the vessels would be a help.
The trick is to extract the brain as soft tissue first.
You may use HD-BET, SwissSkullStripper or TotalSegmentator for this. Once you have a masked volume, tools line FloodFilling or GrowFromSeeds may extract the arteries from a contrast enhanced CT angio with fewer artifacts. The final masked volume may require some manual editing. I found that fewer editing is required with TotalSegmentator.
In any case, the result will be sub-optimal. Veins have intensity ranges that are quite close to those in arteries. Further manual editing will be required.
If you just want to view the arteries quickly without segmenting, VolumeRendering is very good.