The purpose of this study is to gather safety and effectiveness data on Stryker Neurovascular's Next Generation Target Detachable Coil (hereafter referred to as the Citadel Embolization Device), when used with Target Detachable Coils, in the treatment of wide-neck intracranial aneurysms.

In this study, use of the Citadel Embolization Device will be limited to a population of patients with unruptured or ruptured wide-neck aneurysms who meet all study eligibility criteria. The Citadel Embolization Device is intended to endovascularly obstruct or occlude blood flow in intracranial aneurysms.

Inclusion Criteria:

1. Age is ≥18 and ≤80 years
2. Has a single, unruptured or ruptured target intracranial aneurysm that is suitable for endovascular treatment. Definition: For the purposes of this study, a ruptured intracranial aneurysm is defined as one with CT/MRI/LP evidence of subarachnoid hemorrhage attributed to the index aneurysm within the last 60 days.
3. Aneurysm morphology is saccular
4. Aneurysm size is between 6-12 mm
5. Has a wide-neck, saccular aneurysm, either bifurcation or sidewall, with a dome to neck ratio <2 or neck ≥4 mm
6. If the target intracranial aneurysm is classified as ruptured, patient must be neurologically stable with a Hunt & Hess Score of 1 or 2.
7. Must be willing to comply with protocol required procedures and follow up
8. Subject or LAR must be willing to sign and date an IRB approved written informed consent prior to initiation of any screening or study procedures

Exclusion Criteria:

1. Target aneurysm has been previously treated
2. Target aneurysm is in any extradural location, including the extradural cavernous segment
3. Has vessel characteristics, tortuosity or morphology or unfavorable aneurysm morphology (e.g., determined from baseline or preprocedure imaging, or which may be evidenced by excessive resistance felt during the procedure) that would preclude safe endovascular access to the target aneurysm necessary for treatment with the study device
4. Has significant intracranial atherosclerotic disease or stenosis determined from baseline or pre-procedure imaging
5. If the target intracranial aneurysm is classified as ruptured, patient is neurologically unstable or has a Hunt & Hess Score of ≥ 3
6. Has a history of intracranial vasospasm not responsive to medical therapy
7. Has undergone coiling or stenting of a non-target intracranial aneurysm within 30 days prior to study treatment or has a non-target intracranial aneurysm that is expected to be treated within 12 months following the treatment of the target aneurysm
8. Treatment with flow diverting stent implant is anticipated
9. A planned, staged procedure is anticipated
10. Has Moya-Moya disease, arteriovenous malformation(s), arteriovenous fistula(e), intracranial tumor(s), intracranial hematoma(s), any other intracranial vascular malformation, or any previous major intracranial surgery
11. Has had a recent (within 90 days) ischemic stroke, TIA, or intracranial hemorrhage
12. Has a baseline mRS score ≥2
13. Has a known coagulopathy or is on chronic anticoagulant therapy
14. Is pregnant or intends to become pregnant during the study or is breastfeeding
15. Is concurrently involved in another study that could affect outcomes of IA treatment
16. Has evidence of active cancer, terminal illness, high risk of embolic stroke, unstable atrial fibrillation, significant co-morbidities, major surgery ≤ 30 days pre-procedure, psychiatric disorders, substance abuse, or a life expectancy of less than 5 years
17. Has a contraindication to angiography, radiographic contrast agents, or any medications that are typically used during the procedure, and any other contraindications listed in the Investigational DFU
18. Has a confirmed allergy to platinum, tungsten, nickel (e.g. nitinol), or other elements used in the manufacturing of the investigational device