Intracranial Aneurysm Embolization Using Interlocking Detachable Coils. Correlation between Volume Embolization Rate and Coil Compaction.

The relationship between volume embolization ratio . and coil compaction on the intracranial aneurysm occluded using interlocking detachable coils (IDCs) was determined. From February 1994 to October 1996, 7 intracranial aneurysms were embolized using IDCs. Aneurysm capacity (volume) was calculated assuming that aneurysms are ellipsoid of the diameter in 3 planes. Coil volume was calculated assuming that IDCs are cylinders of primary coil. Coil compaction was observed in aneurysms embolized at a volume embolization ratio under 25%. There was no coil compaction in aneurysms embolized at a volume embolization ratio of over 25%. Measurement of the volume embolization ratio is useful to predict coil compaction. Intracranial aneurysms should be embolized at a volume embolization ratio of 25-33%.