A main concern of endovascular treatment is the long-term durability of treatment, that is to say that it is possible for the aneurysm to recanalize (recur) after it has been treated with coils [9]. Some factors in recanalization are incomplete initial occlusion, large aneurysm size, ruptured aneurysm, partially thrombosed aneurysm, and compaction of the coil mass within the aneurysm [9 10]. In a Study by Nguyen [11], incomplete initial aneurysm occlusion, rupture and large aneurysm size were all associated with significant recanalization. Johnston [12] concluded the degree of occlusion after initial treatment to be a strong predictor of the risk of subsequent rupture, which justified attempts to completely occlude aneurysms. Two series of small unruptured intracranial aneurysms [13 14] found recurrence rates between 5.9% and 16.9% with retreatment rates of 1.7% and 2.9%. The majority of retreatments were in small wide necked aneurysms. However, the recurrence rates of small aneurysms is much less than those of large aneurysms (71% vs 35%) [15].