Persistent trigeminal artery detected with standard MRI.

The trigeminal artery is the most common of the primitive carotid-basilar anastomoses to persist into adulthood. Prior to the introduction of MRI, the diagnosis of persistent trigeminal artery (PTA) could only be made at cerebral angiography. This study compares angiography and standard brain MRI in 11 cases of PTA. Nine of the 11 PTAs were identified with MRI. Axial imaging gave the best definition of the course of the PTA.