Carotid-vertebrobasilar anastomosis: magnetic resonance and computed tomographic angiographic demonstration

Jpn J Radiol. 2019 Aug;37(8):565-578. doi: 10.1007/s11604-019-00847-x. Epub 2019 Jun 18.


Carotid-vertebrobasilar (VB) anastomoses are rare and usually found incidentally, but they can have clinical significance. Their variance can represent aneurysm formation at the origin of the anomalous artery, cerebral ischemia due to unique blood flow, or other complications. Thus, recognition and correct diagnosis of these anomalous vessels are important when interpreting magnetic resonance (MR) and computed tomography (CT) angiography. This pictorial essay presents MR and CT angiographic images of several types of persistent fetal carotid-VB anastomoses, including those involving the proatlantal, hypoglossal, and trigeminal arteries as well as their variants. Images depict types 1 and 2 proatlantal arteries, persistent second cervical intersegmental artery, persistent hypoglossal artery (PHA), PHA of external carotid origin, two types of the PHA variant, posterior inferior cerebellar artery arising from the jugular branch of the ascending pharyngeal artery, lateral and medial types of persistent trigeminal arteries (PTAs), and four types of PTA variants.

Keywords: Carotid-vertebrobasilar anastomosis; Cerebral arterial variations; Persistent hypoglossal artery; Persistent trigeminal artery; Proatlantal artery.

Publication types

  • Review

MeSH terms

  • Adult
  • Basilar Artery / abnormalities*
  • Basilar Artery / diagnostic imaging
  • Carotid Arteries / abnormalities*
  • Carotid Arteries / diagnostic imaging
  • Computed Tomography Angiography / methods*
  • Female
  • Humans
  • Magnetic Resonance Angiography / methods*
  • Male
  • Vertebral Artery / abnormalities*
  • Vertebral Artery / diagnostic imaging