title: Rare saccular aneurysm in a medial type persistent trigeminal artery trunk and literature review.
abstract: OBJECTIVE
  We report an extremely rare case of saccular aneurysm in the left medial type persistent trigeminal artery (PTA) trunk and discuss its clinical importance.
  
  
  METHODS
  A 77-year-old woman who had symptom suggestive of vertebrobasilar insufficiency underwent cerebral magnetic resonance (MR) imaging and non-contrast three dimensional time-of-flight MR angiography (3D TOF MRA) using a 3 T scanner.
  
  
  RESULTS
  3D TOF MRA images revealed a left medial type PTA originated from the left internal carotid artery C5 portion, through cavernous sinus and connected to the basilar artery with a saccular aneurysm in the mid portion of its trunk. The basilar artery (BA) under the union was hypoplastic. The bilateral posterior communicating arteries were absent.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of a medial type PTA associated with a saccular aneurysm in the PTA trunk. Being aware of this is crucial in clinical, because they can influence surgical and interventional procedures.
authors.affiliation: Department of Radiology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng, Shandong, 252000, P.R. China, baimin11@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Bai
authors.forename: Qian
authors.initials: Q
authors.lastname: Guo
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000368:Aged; D000783:Aneurysm / Q000473:pathology*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology; D018810:Magnetic Resonance Angiography