The purpose of this trial is to gather data on the safety and effectiveness of the Contour /Contour 021 System in the treatment of wide-necked bifurcated saccular, intracranial aneurysms for submission to FDA in support of a premarket approval application for the device.

The purpose of this trial is to gather data on the safety and effectiveness of the Contour /Contour 021 System in the treatment of wide-necked bifurcated saccular, intracranial aneurysms for submission to FDA in support of a premarket approval application for the device. This trial is a prospective, multicenter single-arm study. Up to 220 subjects will be enrolled at up to 20 participating investigational sites.

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 of 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 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.

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

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) and/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 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. 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.