Epidemiological Insights Into the Formation, Progression, and Rupture of Intracranial Aneurysms: A Retrospective, Multi-Center Hospital-Based Study in China

Inclusion Criteria: 1. IA diagnosis (ruptured or unruptured) or exclusion by digital subtractive angiography (DSA) or by cranial computed tomography angiography (CTA) / magnetic resonance angiography (MRA); 2. Aged ≥ 18 and ≤ 18 years old; 3. With complete demographic data including age and sex; 4. With medical record archiving officially. Exclusion Criteria: 1. Missing data of age, sex or hypertensive status; 2. Age \<18 or \>80 years; 3. Pregnancy; 4. With a history of intracranial arteriovenous malformation, Moyamoya, polycystic kidney disease, Ehlers-Danlos syndrome, Gronblad-Strandberg syndrome, or Marfan syndrome; 5. Suspicion for dissecting or mycotic aneurysms or aneurysm-like lesions that were indistinguishable from the infundibulum, fenestration, dilation, or atherosclerotic remodeling on structural imaging scans.