Frequently it is a wide necked aneurysm with an irregular shape, incorporate parent vessels, and are associated with significant variations in vascular anatomy.
The most common site of rupture of very small intracranial aneurysms was the anterior communicating artery (ACoA). Rupture of small and very small aneurysms is unpredictable, and treatment may be considered in selected high-risk patients according to factors such as young age, ACoA location, and hypertension 4).
A1 segment hypoplasia of the anterior cerebral artery is frequently observed in patients with anterior communicating artery aneurysms. The effect of this anatomical variant on ACoA aneurysm morphology is not well understood 5).