Getting tested for a brain aneurysm typically starts with a non-invasive imaging scan, either a CT angiography (CTA) or magnetic resonance angiography (MRA), ordered by your doctor or a neurologist. Most people don’t need routine screening, but if you have risk factors, symptoms, or a family history, specific testing pathways exist. Here’s what each option involves and how to know which one applies to you.
Who Should Get Screened
Brain aneurysm screening isn’t recommended for the general population. Most unruptured aneurysms never cause problems, and widespread testing would lead to unnecessary anxiety and procedures. But certain groups have a high enough risk that screening makes sense.
The American Heart Association and American Stroke Association recommend screening for two groups specifically: people who have two or more family members (first-degree relatives like parents or siblings) with a brain aneurysm or a type of brain bleed called subarachnoid hemorrhage, and people with autosomal dominant polycystic kidney disease. These are the strongest, most widely accepted criteria. Beyond those two categories, some specialists also recommend screening for anyone who has personally survived a prior brain bleed, since they’re at elevated risk for a second aneurysm.
If you don’t fall into these groups but are still concerned, it’s worth talking to your primary care doctor. Factors like smoking, high blood pressure, and a single family member with an aneurysm may prompt a doctor to consider testing on a case-by-case basis, even if formal guidelines don’t mandate it.
CT Angiography: The Most Common First Test
CT angiography is the test most people will encounter first. It’s fast, widely available, and produces detailed images of the blood vessels in your brain. The scan itself takes only a few minutes, though the full appointment usually runs about 30 to 60 minutes including preparation.
A contrast dye is injected through an IV in your arm, which makes your blood vessels show up clearly on the images. The dye is generally safe, but there are a few things to know before your appointment. You’ll need to fast for three hours beforehand if contrast is being used. If you have diabetes, you can eat a light meal three hours before the scan, but you may be asked to stop certain diabetes medications for 48 hours afterward. People with kidney problems should mention this ahead of time, since the contrast dye can stress the kidneys. If you’ve had an allergic reaction to contrast dye in the past, your team may give you a steroid beforehand to reduce the risk of another reaction, or they may skip contrast entirely and use an alternative approach.
You’ll be asked to remove jewelry and piercings. If you’re pregnant or think you might be, let your doctor know before scheduling.
MR Angiography: No Radiation, No Contrast
MR angiography uses magnetic fields instead of X-rays, which means no radiation exposure. Many MRA protocols also don’t require contrast dye, making this a good option for people with kidney concerns or contrast allergies. The tradeoff is that MRA takes longer (often 30 to 60 minutes inside the scanner) and can be difficult for people who are claustrophobic.
MRA is effective for detecting most aneurysms but has a known blind spot: it can miss small aneurysms under 3 millimeters, as well as aneurysms in certain hard-to-image locations. In one study comparing MRA to the gold-standard catheter angiogram, MRA correctly identified 82% of aneurysms but missed 9 out of 51, all of which were small. For routine screening in someone without symptoms, this level of accuracy is often considered acceptable. But if there’s strong clinical suspicion or if an MRA result doesn’t match your symptoms, your doctor may recommend a more definitive test.
Catheter Angiography: The Most Detailed Option
A catheter-based angiogram, called digital subtraction angiography, remains the gold standard for diagnosing brain aneurysms. It produces the most detailed images of your brain’s blood vessels and can detect aneurysms that CTA or MRA might miss.
The procedure is more involved than a scan. A thin tube (catheter) is inserted into an artery in your leg and threaded up to the blood vessels in your brain. Contrast dye is injected through the catheter while X-ray images are taken. You’ll typically be sedated but awake, and the procedure takes one to two hours. Because it’s invasive, it carries small risks including bleeding at the insertion site, stroke, or allergic reaction to the dye. For that reason, it’s not used as a first-line screening tool. Doctors reserve it for cases where non-invasive imaging was inconclusive, when detailed information is needed before treatment planning, or when a rupture is suspected.
What Happens in an Emergency
If you’re experiencing the sudden, severe headache often described as “the worst headache of your life,” along with symptoms like a stiff neck, blurred vision, nausea, or loss of consciousness, the testing process looks very different from elective screening. In an emergency room, a CT scan without contrast is typically the first step, since it can quickly detect bleeding in and around the brain.
If that initial CT scan is negative but a ruptured aneurysm is still suspected, a lumbar puncture (spinal tap) may follow. This involves collecting a small sample of the fluid surrounding your spinal cord and checking it for blood, which would confirm a bleed the CT missed. A CT angiogram or catheter angiogram is then used to locate the exact source.
How to Start the Process
If you’re not in an emergency and want to be screened, your starting point is your primary care doctor. They can evaluate your risk factors and either order a CTA or MRA directly or refer you to a neurologist. Neurologists handle the diagnostic workup and interpretation. If an aneurysm is found, you’ll likely be referred to a neurosurgeon or an interventional neuroradiologist, who specializes in treating blood vessel problems in the brain.
Insurance coverage for screening varies. If you meet the established criteria (two or more affected family members, or polycystic kidney disease), most insurers will cover the imaging. If you’re requesting screening based on general concern rather than a recognized indication, you may need to advocate for coverage or pay out of pocket. A CTA typically costs between $300 and $1,000 depending on your location and insurance, while MRA costs are in a similar range.
For people who do have a family history or other risk factors, screening is typically done once and then repeated every five to seven years if the initial scan is clean. If a small aneurysm is found, follow-up imaging is scheduled at closer intervals, often every six to twelve months initially, to monitor for any growth.