Anterior communicating artery aneurysm

Findings

The head CT without contrast shows a region of hyper density along the anterior falx along the course of the anterior cerebral artery concerning for acute blood products. CT angiogram shows an anterior communicating artery aneurysm that splays both anterior cerebral arteries and points anteriorly No definite blood products within the suprasellar cistern are seen. There is no intraventricular hemorrhage.


Diagnosis: Anterior communicating artery (ACom) aneurysm (unruptured)


Key points

Aneurysm development and rupture risk reflect complex combination of inherited susceptibility and acquired mechanically-mediated vessel wall stresses4."
Associated with connective tissue disorders such as fibromuscular dysplasia, Ehlers-Danlos syndrome (type IV), ADPCKD
Familial intracranial aneurysms: Occur in clusters of 1st degree relatives

Location: 90% arise from circle of Willis
- 90% anterior circulation (Acom and internal carotid-com most common sites)
- 10 % posterior (Basilar artery bifurcation, PICA most common)
- 1-3% misc sites distal to COW (often traumatic, mycotic, oncotic)

Risk of rupture:
- Increased risk of rupture:
- Size
- Multilobed
- Apical "bleb"
- Length: neck aspect ratio >1.6

Giant aneurysms (>2.5cm) present both the risk of rupture and symptoms related to mass effect
15-20 % multiple
Estimated risk of rupture: 1-2% year cumulative for unruptured aneurysms

Demographics:
- F>M (especially with multiple aneurysms)
- Incidence: 1/100000 (<35yo); 44/100000 (>65yo)

Treatment: Cost-effective strategy for unruptured aneurysms
- Endovascular treatment was most cost effective for anterior circulation aneurysms 7-25 mm in size
- No treatment was most cost-effective for anterior circulation aneurysms < 7mm
- Surgical treatment was most cost effective for anterior circulation aneurysms > 25m
- Endovascular coiling has been accepted as effective treatment, though controversy still exists between surgical and endovascular therapy.

Long-term (10yr) followup of 1036 coiled aneurysms required retreatment in 7% and rebleeding in 0.5%