van der Kamp LT, Rinkel GJE, Verbaan D, et al. - For intracranial aneurysms with growth detected during follow-up, occurrence of rupture within 1 year after growth detection was evident in approximately 1 of 25 aneurysms. This study affords the triple-S risk prediction model that can be employed to estimate absolute risk of rupture for the initial period after detection of growth.

• This is a cohort study involving 312 patients with intracranial aneurysms with growth.

• Rupture occurred in 25 (7.6%) of these aneurysms during 864 aneurysm-years of follow-up.

• Post-growth-detection, the absolute risk of rupture was 2.9%, 4.3%, and 6.0% at 6 months, 1 year, and 2 years, respectively.

• Factors predictive for rupture included size (7 mm or larger hazard ratio, 3.1), shape (irregular hazard ratio, 2.9), and site (middle cerebral artery hazard ratio, 3.6; anterior cerebral artery, posterior communicating artery, or posterior circulation hazard ratio, 2.8).

• One-year risk of rupture ranged from 2.1% to 10.6% in the triple-S (size, site, and shape) prediction model.