Intracranial aneurysm - description of size and neck + calculator
Apart from giving the dimensions of an intracranial aneurysm, its size should be cathegorized according to this table.
| Description | Size |
|---|---|
| Small | ≤5mm |
| Medium | <15mm |
| Large | <25mm |
| Giant | ≥25mm |
The diameter of the neck of the aneurysm is cathegorized as well.
| Description | Size |
|---|---|
| Small neck | ≤4mm |
| Wide neck | >4mm |
In general, there are three basic types of aneurysm shapes, but reportedly, such cathegorisation has little value.
| Description | Size |
|---|---|
| Saccular aneurysm | saccular round outpouching from the artery |
| Berry aneurysm | a type of saccular aneurysm with a neck (and therefore resembling a berry) |
| Fusiform aneurysm | aneurysm without a stem, widening of a segment of an artery |
The volume of an aneurysm, whether spheroid, ellipsoid, or cylindrical, can be estimated by the following formula (extrapolation to ellipsoid):
Volume=1/6 x Pi x length x width x height
| Parameter | Value | |
|---|---|---|
| Height* | mm | |
| Width* | mm | |
| Length (if only 2D imaging then use the same value as Width)* | mm | |
* Required
Volume:
References:
1. Meyers PM, Schumacher HC, Higashida RT, Derdeyn CP, Nesbit GM, Sacks D, et al. Reporting Standards for Endovascular Repair of Saccular Intracranial Cerebral Aneurysms. Stroke. 2009 May 1;40(5):e366–e379.
2. Hacein-Bey L, Provenzale JM. Current Imaging Assessment and Treatment of Intracranial Aneurysms. American Journal of Roentgenology. 2011 Jan;196(1):32–44.