Segmentation of aortic branches : how would you do it?

Hello everyone !
I’m looking to segment aortic, and especially mesenteric vessels from post-op CT scans after colectomy.
My senior researcher wants me to do something like this :

On a CT scan with similar constrats between portal and arteric vessels : how would you do it ?
For example, like this

In fact, I need more the arteric vessels than the portal ones.

I don’t know if i should choose local treshold or manual painting with maybe grow from seeds ?
How would you do it ?
Thanks a lot