Unruptured saccular intracranial aneurysms larger than 7 mm can be treated with endovascular occlusion using detachable coils, with or without expendable stent assistance. A new endovascular technique has recently been developed, using flow diverter stents without associated coils. Clinical results already published are encouraging but have to be confirmed. Furthermore, these medical devices are expensive in comparison to the coiling strategy. The purpose of this study is to compare the clinical efficacy, safety, and cost-effectiveness of endovascular coiling and endovascular flow diversion for unrupted saccular intracranial aneurysms.

Main Outcome Measure: Percentage of patients with an aneurysm with complete occlusion, defined as the absence of visible blood flow to the consideration of angiography performed 12 months post-endovascular intervention.

Inclusion Criteria:

• Patient's age ≥ 18 years old
• Unruptured saccular intracranial aneurysm diagnosed by angiography or CT angiography or MR angiography, located in the intra-dural area, with a neck diameter between 4 and 10 mm, with a sac diameter between 7 mm and 20 mm, with a ratio "dome/nek" greater than 1, and with a diameter of the parent artery between 2 and 5 mm.
• No prior treatment of the aneurysm
• Agreement for participating in the study and informed consent signed by the patient
• Patient affiliated to a social security scheme

Exclusion Criteria:

• Patient's age < 18 years old
• Adult patient protected by law
• Contraindications to the endovascular procedure
• Contraindications to antiplatelet or anticoagulant treatment
• Prior treatment of the aneurysm
• Presence of an arteriovenous malformation
• Extradural location of the aneurysm
• Fusiform aneurysm
• Active bacterial infection (clinical signs)
• Intracranial hemorrhage from aneurysm in the previous month
• Pregnant or breastfeeding woman