The physiopathology of intracranial aneurysm from initiation to ruptured is incompletely understood but included inflammation. The microbiota is known to interact with brain and can promote inflammation. The objective of this study is to describe microbiota with taxonomic and metabolomic analysis. A comparison between ruptured and unruptured intracranial aneurysm will be performed. The study hypothesis is that microbiota is different between ruptured and unruptured patient.

Inclusion Criteria:

• one or more intracranial sacciform aneurysm ruptured or not in function of the inclusion group

Exclusion Criteria:

• Transient modification of microbiota: Antibiotherapy in the last 3 months, pre or probiotic in the last month, gastrostomy, ileostomy, bariatric surgery, digestive tract resection, gastro-duodenal ulcer surgery or during the last month, chronic inflammatory disease of the digestive tract (like Crohn), BMI for more than 30, Very restrictive diet (like vegan
• Specific pathologies increasing the incidence of aneurysm ( kidney autosomic dominant polycystosis, Type 1 neurofibromatosis, Rendu-Osler, MArfan
• Participation to a study with the objective of microbiota modification

adult patients with ruptured aneurysm and unruptured aneurysm