Persistent Trigeminal Artery
FINDINGS:
3D TOF MRA of Circle of Willis shows a large vessel arising
from the posterior aspect of the right cavernous C4 segment and connecting
with the mid basilar artery. Left PCOM is absent or hypoplastic.
DISCUSSION:
Persistent trigeminal artery is the most common of persistent
primitive carotid-vertebrobasilar anastomosis, and is seen in approximately
0.5% of all angiograms performed. Other rare primitive connections include
proatlantal intersegmental artery, Otic artery, and Hypoglossal artery.