Purpose: Recanalization of the aneurysm sac is a major drawback of endovascular embolization that often necessitates retreatment. Recent evidence suggests that increased packing density of coils within the aneurysm sac may lower recanalization rates. The DeltaPaq microcoil system (Micrus Endovascular, San Jose, California, USA), designed to increase aneurysm packing density, features an initial wind design with a triangular profile and microscopic rotating rings which provides the coil with a low moment of inertia and the ability to easily change the coil's angular motion. Here, we performed safety and packing density analysis of DeltaPaq coils in the treatment of ruptured …