Aneurysm Packing With the Expandable TrelliX Coil System - A Prospective Safety Study

Inclusion Criteria: * Subject age ≥18 and ≤80 years with a diagnosis of a ruptured or unruptured intracranial aneurysm judged suitable for selective endovascular treatment by coil occlusion during single procedure * Aneurysm size \[largest measurement from the cross sectional images to determine overall aneurysm size, not just the lumen) ≥5 mm and ≤16mm * If ruptured aneurysm: either WFNS grade 1 or 2, or Hunt and Hess 1 or 2 * If unruptured aneurysm: Subject grade Modified Rankin Scale mRS 0 - 2 * Investigator plans to use ≥70% in volume TrelliX coils to fill target aneurysm Exclusion Criteria: * Prior treatment (surgical or endovascular) of the target aneurysm * Planned treatment of multiple aneurysms in index procedure * Planned use of other modified coils (Matrix, HydroCoil or fibered coils) * Planned use of liquid embolic material * Life expectancy less than 12 months * Presence of arteriovenous malformation * Fusiform, mycotic, traumatic, or tumoral aneurysms * Intended or planned aneurysm treatment by parent vessel occlusion * Clipping or endovascular treatment of another intracranial aneurysm performed within 30 days before or planned within 30 days following the index procedure