Brain aneurysm screening if it runs in the family
A brain aneurysm is a swelling in a blood vessel in the brain. If it bursts it can cause a bleed on the brain, but this is rare. (NHS) MedlinePlus says 1 in 50 people has one, that only a small number cause symptoms or burst, and that family history is a risk factor. (MedlinePlus) This page covers who guidance says may be offered a scan because of family history, not treatment. For aneurysm scans in polycystic kidney disease, see screenings for people with polycystic kidney disease.
The main guidance
The American Heart Association and American Stroke Association (AHA/ASA) guideline on the primary prevention of stroke (2014) has recommendations on screening for unruptured brain aneurysms by family history and some inherited conditions. (AHA/ASA, 2014) The AHA/ASA guideline on unruptured intracranial aneurysms (2015) also covers screening, but its full text is not openly available. (AHA/ASA, 2015) The Korean guideline on bleeding from brain aneurysms (2018) gives its own recommendation and quotes the AHA/ASA 2012 and European Stroke Organisation (ESO) 2013 advice. (Korean guideline, 2018) The ESO guideline on unruptured aneurysms (2022) says the risk of having or developing one is considerably higher in people with two or more first-degree relatives who had a bleed from a burst aneurysm, and in people with polycystic kidney disease. (ESO, 2022)
Who may be offered a scan
| Situation | What guidance says | Source |
|---|---|---|
| Two or more first-degree relatives with an aneurysm or a bleed from one | Screening might be reasonable (AHA/ASA); recommended (Korean guideline); should be considered (ESO 2013) | (AHA/ASA, 2014)(Korean guideline, 2018) |
| Only one relative with an aneurysm or a bleed | Not recommended (AHA/ASA 2014); in general not advised (ESO 2013) | (AHA/ASA, 2014)(Korean guideline, 2018) |
| Polycystic kidney disease (ADPKD) with a relative with ADPKD and an aneurysm or bleed | Screening may be considered; see the polycystic kidney disease page for KDIGO 2025 | (AHA/ASA, 2014) |
| Every carrier of ADPKD or vascular Ehlers-Danlos (type IV) | Screening of every carrier is not recommended | (AHA/ASA, 2014) |
| Fibromuscular dysplasia of the neck arteries | Screening may be considered | (AHA/ASA, 2014) |
| A past bleed from a brain aneurysm | Regular scans for new aneurysms are a screening group in the Korean guideline on unruptured aneurysms | (Kim, 2021) |
The AHA/ASA 2014 guideline says brain aneurysms are a feature of some inherited conditions, including ADPKD and vascular Ehlers-Danlos syndrome, and occur in about 8 percent of people with ADPKD and 7 percent with fibromuscular dysplasia of the neck arteries. (AHA/ASA, 2014) The NHS also lists a close relative with a brain aneurysm, ADPKD and Ehlers-Danlos syndrome among the things that raise the chance of having one. (NHS) See family history and screening and how to collect your family health history.
Which scan
The AHA/ASA 2014 recommendations are for noninvasive screening. (AHA/ASA, 2014) In the Dutch family screening cohort, magnetic resonance angiography (MRA) or CT angiography (CTA) was used. (Bor, 2014) The Korean guideline says MRA is widely used as a screening test because its sensitivity is comparable to catheter angiography and it is less invasive. (Korean guideline, 2018) MedlinePlus lists CTA and MRI or MRA among the tests used to find a brain aneurysm. (MedlinePlus)
From what age and how often
The AHA/ASA 2014 guideline does not set an age or an interval. (AHA/ASA, 2014) In a Dutch cohort of people with two or more first-degree relatives with a bleed or an aneurysm, screening was done from age 16 to 18 up to 65 to 70, and after a clear scan people were advised to come back after 5 years. Aneurysms were found in 11 percent at the first screen, 8 percent at the second and 5 percent at the third and fourth. Of people with no past aneurysm and two clear scans, 3 percent had a new aneurysm at a later screen, and 5 percent of those screened before 30 had one. (Bor, 2014) The authors advocate long-term repeat screening in this group, while noting the risk of a bleed between scans is not removed. (Bor, 2014) The Dutch study authors write that for people with only one first-degree relative who had a bleed, screening twice, at 40 and 55, may be considered, with about 4 percent found at the first screen. (Mensing, 2023)
Why most people are not screened
The ESO guideline says up to 3 percent of adults have an unruptured brain aneurysm. (ESO, 2022) The Dutch study authors write that screening can have downsides, including effects on quality of life and the risks of treatment for an aneurysm that may never burst, so it should ideally only be done in people with a high lifetime risk of a bleed. (Mensing, 2023) In their study of 461 parents, brothers, sisters and children of people with an unruptured aneurysm and no family history of a bleed, about 5 percent had an aneurysm; all were small with a low risk of bursting, and none needed treatment. They do not currently advise screening in that group. (Mensing, 2023) For whole-body scans offered to anyone, see full-body MRI screening.
Routine age-based screening
These scans are added to, not instead of, the routine screenings for your age; see screenings by age and gender.
When to contact a provider
MedlinePlus, aneurysm in the brain, when to contact a medical professional: (MedlinePlus)
- Go to the emergency room or call 911 or the local emergency number if you have a sudden or severe headache, especially if you also have nausea, vomiting, seizures, or any other nervous system symptom.
- Also call if you have a headache that is unusual for you, especially if it is severe or your worst headache ever.
Where they differ:
- Only one affected relative. The AHA/ASA 2014 guideline says screening is not recommended (AHA/ASA, 2014) and ESO 2013 says it should in general not be advised, while the AHA/ASA 2012 aSAH guidance quoted in the Korean guideline says it may be reasonable to offer it after a bleed in at least one first-degree relative. (Korean guideline, 2018) A 2021 systematic review argues in favor of screening people with one affected first-degree relative. (Van Hoe, 2021)
- How strong the advice is for two or more relatives. The AHA/ASA 2014 guideline says screening might be reasonable, a weak recommendation; (AHA/ASA, 2014) the Korean guideline says a screening test is recommended. (Korean guideline, 2018)
- Repeat scans. The AHA/ASA 2014 guideline sets no interval; (AHA/ASA, 2014) the Dutch cohort advised coming back after 5 years and found new aneurysms even after two clear scans. (Bor, 2014)
- Polycystic kidney disease. The AHA/ASA 2014 guideline ties screening to a relative with ADPKD and an aneurysm or bleed; (AHA/ASA, 2014) the newer KDIGO 2025 advice is on the polycystic kidney disease page.
Your doctor decides what your result means for you.
Questions people ask
My parent had a brain aneurysm. Should I be screened?
With only one affected relative, the AHA/ASA 2014 stroke prevention guideline says screening is not recommended, and the ESO 2013 guidance quoted in the Korean guideline says it should in general not be advised. The AHA/ASA 2012 guidance quoted there says it may be reasonable to offer it after a bleed from an aneurysm in at least one first-degree relative. Your doctor decides with you. (AHA/ASA, 2014) (Korean guideline, 2018)
Who is usually offered a scan?
People with two or more first-degree relatives (parents, brothers, sisters or children) who had a brain aneurysm or a bleed from one. The AHA/ASA 2014 guideline says screening might be reasonable for them, and the Korean 2018 guideline recommends it. (AHA/ASA, 2014) (Korean guideline, 2018)
What scan is used?
A noninvasive scan: magnetic resonance angiography (MRA) or CT angiography (CTA). The Korean guideline says MRA is widely used for screening because its sensitivity is comparable to catheter angiography and it is less invasive. (AHA/ASA, 2014) (Korean guideline, 2018) (Bor, 2014)
If my first scan is clear, is that the end of it?
Not always. In a Dutch cohort of people with two or more affected first-degree relatives, aneurysms were found in 8 percent at the second screen and 5 percent at the third and fourth, and 3 percent of people with two clear scans later had a new one. People were advised to come back after 5 years. (Bor, 2014)
Why is everyone not screened?
Up to 3 percent of adults have an unruptured brain aneurysm, and only a small number burst. The Dutch study authors write that screening should ideally only be done in people with a high lifetime risk of a bleed, because many aneurysms found carry a low risk and finding them has downsides. (ESO, 2022) (Mensing, 2023) (MedlinePlus)