Can small brain aneurysms be safely watched instead of treated?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria : * UIA (Unruptured Intracranial Aneurysms) located in an intradural position, with confirmed presence on CT (Computed Tomography) angiography or conventional cerebral angiography. * Largest diameter between 2 mm and 7.9 mm inclusive in height or width (excluding oblique measurements). * Patients with one or more UIAs, provided that at least one aneurysm (index aneurysm) fulfills all inclusion criteria and is selected for study evaluation. * Patients aged ≥ 35 years to 75 years. * Patients must have signed informed consent. * Patients must be affiliated with the French healthcare system. Exclusion Criteria : * Aneurysms deemed inoperable by endovascular or surgical techniques, and patients with absolute contraindications to anaesthesia. * Patients with a disease reducing life expectancy to less than 3 years. * Patients with a mRS score of ≥2. * Patients with a history of prior treatment for a cerebral aneurysm (ruptured or unruptured). * History of unexplained SAH (Subarachnoid Haemorrhage). * UIA discovered in the context of a recent thunderclap or exertional headache. * Fusiform, mycotic, or intracavernous UIAs. * Infundibulum of the posterior communicating artery (PcomA) and choroidal artery. * Very distal saccular UIAs: A3/A4, M3/M4, P3/P4. * UIA associated with brain AVM (Arteriovenous Malformation). * Patients presenting with multiple UIAs in whom at least one aneurysm measures ≥ 8 mm, in order to avoid inclusion of patients at higher overall rupture risk not compatible with the study population. * Pregnancy or a desire for pregnancy during the study period. * Patients with autosomal dominant polycystic kidney disease (ADPKD), hereditary connective tissue disorders (HCTDs), or sickle cell disease (SCD). * Current participation in another interventional research study. * Patients likely to fail to attend follow-up visits or adhere to the protocol. * Allergy to iodinated contrast material. * Severe renal impairment (Glomerular Filtration Rate (GFR) \< 30 mL/min/1.73m2).