Has anyone here ever been told that they have an incomplete Circle of Willis when they received an MRA or MRI report?  I have been reading literature on the connection between swelling in the carotid artery (the one that pushes on the trigeminal nerve and causes our pain) and the inability of the missing vessels to accommodate the extra blood flow, and the possible relationship to migraine ans stroke.  My sister and I both have this.  She had a massive stroke at 42 from aneurysm on right carotid (severely disabled now); I suffer severe episodic CH; my mother suffered debilitating migraines for 55 years. 
Has anyone out there received a diagnosis of "incomplete Circle of Willis"?  I'm doing an informal survey...nothing statistical, just back-of-the-envelope.
Thanks.