A retrospective analysis including CT angiograms obtained from October 2011 to October 2012 and reported by neuroradiologists senior at our institution was performed.
We classified the images findings in normal variants or vascular anomalies.
Fig. 18
The most frequent findings in the Circle of Willis are:
1) Normal variants: hypoplasias (25,8%),
fetal presentation of the posterior cerebral artery (12,3%) .
2) Anomalies: anterior communicating complex anomalies as anterior cerebral artery azygos or bihemispheric,
abnormalities of the origin of the middle cerebral artery and fenestrations.
Fig. 19: Fenestration of basilar artery asociated with aneurysm.
A. Before interventional procedure.
B. After embolization
Fig. 20: Azygos. DSA.
A.AP view. Right carotid artery angiogram.
B.AP view. Left carotid artery angiogram.
At SAT our analysis found:
1) Normal variants,
common hypoplasia of the vertebral artery (VA) (8,6 %),
a common SAT trunk and origin of left VA in aorta.
2) Anomalies were aberrant subclavian artery and retropharyngeal internal carotid.
Fig. 21: Retropharyngeal carotid associated with dissecant aneurysms
Fig. 22: Retropharyngeal carotid associated with dissecant aneurysms
We also detected uncommon anomalies in literature,
such as embryonic anastomosis like persistent trigeminal artery or persistent hypoglossal artery,
aberrant internal carotid artery or posteroinfeior cerebellar artery originated from internal carotid artery.
Fig. 23: Temporal anterior branch originated in ICA, associated with aneurysm
Fig. 24: A. PICA with origin in ICA.
B. In this patient was asociated with AVM.