The endovascular treatment of intracranial aneurysms has become an accepted alternative to surgical repair given the many recent advances with neurointerventional devices and procedures. The introduction of GDC coils in 1993 provided physicians and their patients a less invasive treatment option. Additionally, the results of two large international trials, ISAT and ISUIA, have shown the benefits of endovascular treatment over surgery for treatment of specific types of aneurysms. One limitation of endovascular coil embolization is aneurysm recurrence or recanalization which is not infrequently observed angiographically at follow up. Aneurysm recanalization may be a result of aneurysm morphology, anatomic location and flow orientation, aneurysm regrowth or the degree of coil compaction. Despite the widespread adoption of endovascular aneurysm coiling, there remains much to be learned about the efficacy and optimization of this treatment modality.