In recent years, endovascular treatment of intracranial aneurysms has seen remarkable growth, now surpassing traditional surgical approaches in terms of frequency of use. However, this transition to endovascular methods is not without its challenges. This type of procedure requires careful selection of the device to be implanted, a decision that is still based on manual two-dimensional measurements. This method is questionable, as it does not always take into account the complexity and specificities of certain aneurysms, where three-dimensional geometry can play a crucial role. As a result, these procedures carry significant risks, such as the need for additional maneuvers to remove or reposition devices, or even deploy another support device, which potentially increases the risk of perioperative complications, the duration of surgery, and the amount of radiation required for imaging. Beyond the impact on the patient, these complications also result in additional costs for the healthcare system, expenses that could likely be avoided if more precise and appropriate tools were used from the outset of the procedure. In this context, optimizing the choice of endovascular devices could have both clinical and economic impacts. Innovative technology such as Sim&Size, which supports healthcare professionals in their therapeutic decisions and choice of the appropriate endovascular device, should therefore improve the effectiveness and efficiency of endovascular treatments.

Sim&Size is a Software as a Medical Device (SaMD) intended to provide a 3D view of the final placement of neurovascular implantable medical devices of the following types: flow diverters, intrasaccular devices, stent devices, and coils. It uses an actual image of the patient produced by 3D rotational angiography. It offers physicians the possibility of simulating the deployment of implantable medical devices in the artery to be treated and predicts the final placement and the extent of apposition of the implant. Sim&Size has CE marking and FDA clearance.

This study is a prospective, randomized, multicenter study whose main objective is to show that the use of Sim&Size during the standard endovascular procedure, compared with a standard endovascular procedure without Sim&Size, reduces both the actual costs of the hospital stay and the rate of perioperative complications.

Inclusion Criteria:

• Patients aged ≥18 years planned to be treated endovascularly for unruptured intracranial aneurysms.
• Planned implantable device models is available in the Sim&Size simulation database and used following their approved indications.
• Affiliated with the French social security system.
• Signed the information and consent form

Exclusion Criteria:

• Patients scheduled to undergo endovascular treatment with stents only
• Patients presenting for treatment of a ruptured aneurysm
• Patients who have already been treated in the planned deployment area and whose previous treatment presents a potential contact with the new implant.
• Giant intracranial aneurysm resulting in poor-quality reconstruction in the potential deployment area of the implant during 3DRA acquisition
• Presence of artifacts on the 3DRA in the potential deployment area of the implant
• Patients with multiple aneurysms whose treatment is planned during a single procedure and who require separate individual therapeutic strategies. Examples of individual therapeutic strategies excluded from the study: placement of two separate flow diverters without telescopic technique, individual coiling of each aneurysm.
• Patients for whom pre-planning was performed using Sim&Cure software prior to patient randomization.
• Pregnant or breastfeeding women.
• Patients under guardianship or conservatorship.
• Emergency situations.