Intracranial aneurysm are frequent with a prevalence estimated over 2-5% in the general population. These are focal dilatations occuring in the cerebral vessels. They usually remain silent until complications occur. Complications associated with intracranial aneurysms include mass effect on adjacent structures and rupture. Rupture is the most severe complication with a mortality rate of 35-50% and a high rate of morbidity including long-term disability. It incidence is estimated about 1% per year for aneurysm smaller than 1 cm.

However, preventative treatments have their own risk of complication and morbi-mortality rate including stroke and hemorrhage. Actual guidelines for treatment planning are mainly designed with the size, the location and the age of the patient. This is why working on the identification of imaging markers of aneurysmal instability is relevant.

Dynamic CTA (Computed Tomography Angiography) acquisition allow to study the variation of metrics such as dome height, dome length, ostium width, ostium area, and volume during the cardiac cycle. The goal of this study is to assess different aneurysmal metrics to determine those which may vary the most during the cardiac cycle and to assess it as an imaging marker of aneurysmal instability.

Inclusion Criteria:

• Patient with an intracranial aneurysm assessed with a 4D CTA

Exclusion Criteria:

• Minor
• Refusal to participate

Patients suffering from at least one intracranial aneurysm and who benefited from a 4D CTA in our institution.