Azygos anterior cerebral artery
An azygos anterior cerebral artery is an uncommon to rare variant seen in approximately 0.4 -1% of the population in which the two A1 segments of the ACA join to form a single trunk. As a result no anterior communicating artery is present. This organization is similar to that seen in lower primates .
It is associated with numerous abnormalities, including:
• dysgenesis of the corpus callosum
• lobar holoprosencephaly
• septooptic dysplasia
• porencephalic cysts
• arteriovenous malformations (AVM)
Berry aneurysms are often seen at the eventual bifurcation of the single vessel, due to either altered haemodynamics or congenitally abnormal wall or both. The reported incidence varies widely from 13 to 71% .
As there is frequent a) hypoplasia of the ACOM and b) contralateral supply of the medial surface of the hemispheres by the ACA branches, confirmation of an azygos ACA can be difficult on angiography . Cross compression views can be helpful.
References
http://radiopaedia.org/articles/azygos-anterior-cerebral-artery
No comments:
Post a Comment