This is a prospective multicenter international single-arm observational study to demonstrate that use of stent-assisted coiling with LVIS™ Evo™ and HydroCoil® Embolic System (HES) in intracranial aneurysm treatment is effective and safe when assessed at 1 year after the procedure

Patient treatment and follow-up will be performed as per standard of care. The study will evaluate the proportion of aneurysms with complete occlusion based on Raymond-Roy occlusion classification (RROC) at 12 ± 6-months, as well as other effectiveness and safety endpoints such as the occurence of stent stenosis or parent artery occlusion, the occurence of retreatment and recanalization, the rate of major ipsilateral stroke or neurological death, the proportion of patients with good functional clinical outcome, the occurence of SAH, aneurysm rupture, procedural complications, serious adverse events...

Sample size: 200 patients

Inclusion Criteria:

• IC 1. Patient whose age is 18 years old or above;
• IC 2. Patient (or legal representative, where applicable) who understands the study requirements and the treatment procedures and provides written informed consent before any study-specific procedures are performed;
• IC 3. Patient eligible for the treatment with LVIS™ Evo™ and HydroCoil® Embolic System (HES);
• IC 4. Patient whose target aneurysm is unruptured or ruptured (> 30 days since occurrence);
• IC 5. Patient whose target aneurysm size is less than or equal to 12 mm;
• IC 6. Patient willing to comply with all planned follow-ups and evaluations.

Exclusion Criteria:

• EC 1 Patient who has suffered an intracerebral hemorrhage within 30 days prior to the procedure;
• EC 2. Patient whose target aneurysm is a fusiform aneurysm;
• EC 3. Patient whose target aneurysm has previously been treated with a stent;
• EC 4. Patient whose target aneurysm is partially thrombosed;
• EC 5. Patient whose target aneurysm requires Y stenting;
• EC 6. Patient whose target aneurysm is associated with an arteriovenous malformation (cAVM), or any other lesion that could lead to hemorrhagic complications;
• EC 7. Patient who has more than one aneurysm to be treated during the same procedure, (except in case of an adjacent aneurysm that could be treated with the same stent);
• EC 8. Patient for whom the treatment with another stent than LVIS™ Evo™ or in addition to LVIS™ Evo™ is planned;
• EC 9. Patient with a planned treatment of other aneurysm in the same vascular territory within 12 months;
• EC 10. Patient who has a known allergy to contrast agents (that cannot be adequately premedicated) and/or to the study device or procedure-required concomitant medications or procedures (e.g. contraindication to antiplatelet and/or anticoagulants, allergy to Nickel-titanium or contraindication to MRI/MRA or angiography);
• EC 11. Patient who has one of the following (as assessed prior to the index procedure): Other serious medical illness (e.g., cancer or any severe or fatal comorbidity) with estimated life expectancy of less than the study duration, OR Planned procedure that may cause non-compliance with the protocol or confound data interpretation;
• EC 12. Patient who is participating or intends to participate in another study that changes the site practice (interventional) within the study time period;
• EC 13. Pregnant or breastfeeding woman.

Patients presenting with an unruptured or ruptured (> 30 days since occurrence) intracranial aneurysm eligible for endovascular treatment using LVIS™ Evo™ and HydroCoil® Embolic System (HES)