The goal of this clinical trial is to collect additional data to demonstrate if the Contour Neurovascular System (CNS) is a safe and effective treatment of wide-necked, saccular, intracranial aneurysms.

Participants will:

Undergo treatment with the Contour Neurovascular System Complete follow-up visits at 1month, 12months, and 24 months, following their procedure Report any adverse events to their study team

Inclusion Criteria:

1. Patient is 18-75 years of age at the time of screening.

2. Patient has a single ruptured or unruptured IA requiring treatment. If the patient has an additional IA requiring treatment, the additional IA must not require treatment within 60 days after the index procedure.

3. The target IA must have the following characteristics:

   • Saccular morphology
   • Located at a bifurcation in the anterior or posterior circulation
   • Aneurysm neck diameter between 2 and 10 mm and aneurysm equatorial diameter between 2 and 10.5 mm
   • Wide-necked, defined as neck size ≥ 4 mm or a dome/neck ratio < 2

4. Patient may be treated with Contour without the use of additional implanted devices.

5. Patient is able to comply with all aspects of the screening, evaluation, treatment, and the post-procedure follow-up schedule.

6. Patient or legally authorized representative has signed and dated an institutional review board (IRB)/Ethics Committee (EC)-approved written informed consent prior to initiation of any study procedures.

   FOR PATIENTS WITH UNRUPTURED ANEURYSM

7. Patient meets the criteria outlined in the "Guidelines for the Management of Patients With Unruptured Intracranial Aneurysms" as published by the AHA/ASA^6

   FOR PATIENTS WITH RUPTURED ANEURYSM

8. Patient meets the criteria outlined in the "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage: A Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association" as published by the AHA/ASA.^6

9. Patient must be neurologically stable with Hunt & Hess Score of I, II or III.

(^6: 6 https://www.ahajournals.org/doi/full/10.1161/STR.0000000000000070)

Exclusion Criteria:

1. Anatomy or physiology considered unsuitable for endovascular treatment with the Contour device by the implanting physician and/or the Patient Selection Committee
2. Target IA contains other devices/implants (e.g., coils) that could interfere with the correct placement of the Contour device
3. Subject has a known, untreatable hypersensitivity to contrast dye, iodine, or any component of the treatment device.
4. Contraindication to anticoagulants or anti-platelet medications
5. Stenosis of the target IA's parent vessel is >50%
6. Anticoagulation medications (e.g., warfarin) that cannot be discontinued
7. Acute / chronic renal failure (unless on dialysis) or creatinine > 2.00 mg/dl or > 182 μmol/L
8. Vascular disease or other vascular anomaly that precluded the necessary access to the aneurysm for use of the study device.
9. Clinical, angiographic or computed tomography (CT) evidence of vasospasm, vasculitis, an intracranial tumor (except small meningioma) or any other intracranial vascular malformations on presentation.
10. Conditions placing them at high risk for ischemic stroke or had exhibited ischemic symptoms such as transient ischemic attacks, minor strokes, or stroke-in-evolution within the prior 60-days.
11. Any circulatory, neurovascular, cardiovascular, or neurologic conditions that can result in unstable neurological symptoms (e.g., multiple sclerosis, established seizure disorder).
12. Modified Rankin Scale (mRS) score ≥ 2 prior to presentation or rupture (as applicable).
13. Subarachnoid hemorrhage (SAH) from a non-index aneurysm or any other intracranial hemorrhage within 90 days.
14. Physical, neurologic or psychiatric conditions which precluded his/her ability to comply with all aspects of the screening, evaluation, treatment, and the post-procedure follow-up schedule.
15. Pregnant, breastfeeding or planning pregnancy in the next 2 years
16. Subject is enrolled in another device or drug study in which participation could confound study results.
17. Life expectancy of less than 2 years due to an illness or condition other than the index intracranial aneurysm.