- >25mm (giant)
- Risk of rupture 6%/yr
- Reasons why giant aneurysm have poorer outcomes
- Aneurysm’s intimate association with small perforators,
- The broad aneurysm neck,
- Intraluminal thrombosis,
- Atherosclerosis in the aneurysm neck or dome.
- Types
- Saccular (berry)
- Fusiform
- Numbers
- 3% of all intracranial aneurysm
- 30-60 yrs Peak age of presentation
- Female to male: 3: 1
- Presentation
- 35% haemorrhage
- Bleeding rate is <2% per year (nongiant is 2%/yr)
- TIA by emboli or flow reduction
- Mass compression
- Causing CN3 palsy
- Brainstem compression
- Radiology
- Angiogram
- Often underestimates the size of the lesion due to thrombosed regions of the aneurysm
- CT scan
- May show contrast enhancement surrounding the aneurysm: aneurysm inflammation —> sign of inc. vascularity
- Required to visualise thrombosed places of aneurysm
- MRI scan
- Turbulence within —> complicated T1W1 image
- Pulsation artefact: linear distortion radiation through aneurysm on MRI can differentiate giant aneurysm from solid or cystic lesion
- Treatment
- Endovascular treatment
- Has high recanalization rate with coiling (ISAT: 90% for giant aneurysm)
- Direct surgical clipping: only possible in 50% cases
- High- flow bypass surgery
- Trapping
- Proximal artery ligation (hunterian ligation): used for vertebral-basilar aneurysm results in improvement of CN nerve deficit
- Wrapping
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