This is a retrospective, hospital-based and multi-center study aiming at investigating the potential exposures associated with the formation, progression, and rupture of intracranial aneurysms in Chinese population.

A striking conflict exists between the fatal rupture of intracranial aneurysms (IA) and the passive approach to detecting IA through cerebrovascular examinations. This is attributed to a limited understanding of risk factors for IA incidence and the resulting lack of cost-effective IA screening.

This study aims to gain epidemiological insights into the exposures associated with the risk of IA incidence, including formation, progression, and rupture in the Chinese population. It integrates multi-modal data based on large-scale electronic medical records from high-volume stroke centers across China to investigate potential associations between various exposures and IA incidence.

Patients with anonymous and unique IDs were screened for the presence of IA by formal readings from digital subtraction angiography (DSA), cranial computed tomography angiography (CTA), or magnetic resonance angiography (MRA) conducted by two radiologists, which were then confirmed by two treating neurosurgeons using the raw images. Using natural language processing in conjunction with medical records and multi-modal data, patient exposures were extracted and assumed to be absent if no documentation was found across the databases.

Through a series of retrospective analyses, we aim to identify the exposures associated with IA incidence as much as possible to gather valuable insights for future prospective research.

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.

The study population underwent cerebrovascular examinations, with the majority conducted in clinical settings and the minority for health screening purposes, sourced from real-world electronic medical record databases.