AAA ultrasound: what to expect
An abdominal aortic aneurysm (AAA) is a bulge in the main artery in the belly. Screening is one ultrasound of the abdomen, done once: it uses sound waves, no radiation, and usually takes less than 30 minutes. Your doctor decides whether you need it. (USPSTF, 2019) (MedlinePlus, 2024)
Who is offered the scan
- Men 65 to 75 who have ever smoked (100 or more cigarettes): one-time screening, grade B. (USPSTF, 2019)
- Men 65 to 75 who have never smoked: offered selectively rather than to all, weighing medical and family history, other risk factors and personal values (grade C). (USPSTF, 2019)
- Women 65 to 75 who have ever smoked or have a family history of AAA: the evidence is insufficient to recommend for or against (I statement). (USPSTF, 2019)
- Women who have never smoked and have no family history: the USPSTF recommends against screening (grade D). (USPSTF, 2019)
The NHLBI lists some wider groups that may be screened, for example men 65 to 75 with a first-degree relative (parent, sibling or child) who had an AAA, and people with peripheral artery disease. (NHLBI, 2022) The USPSTF notes that a family history in a first-degree relative doubles the risk. (USPSTF, 2019) Full details: AAA screening.
How to prepare
- You will likely be asked not to eat or drink for several hours before the scan; your provider will tell you what to do. (MedlinePlus, 2024) (RadiologyInfo, 2024)
- Wear loose, comfortable clothes and leave jewelry at home. You may be asked to wear a gown. (RadiologyInfo, 2024)
What happens during the scan
You lie down, and a clear, water-based gel is spread on your belly; it may feel a little cold and wet. A handheld probe (transducer) is moved over the skin, and the sonographer may press it against your abdomen. You may be asked to change position or hold your breath for a few seconds. (MedlinePlus, 2024) A Doppler setting may be used to look at blood flow through the aorta. (RadiologyInfo, 2024) Most of the time it takes less than 30 minutes. (MedlinePlus, 2024)
There is no needle and no ionizing radiation, and there is no known risk. It may be briefly uncomfortable but should not be painful. (MedlinePlus, 2024) (RadiologyInfo, 2024) Gas in the bowel or a larger body can sometimes block part of the view of the aorta. (RadiologyInfo, 2024) (RadiologyInfo, 2024)
How accurate it is
The USPSTF says ultrasound is simple, noninvasive and finds AAA with high sensitivity (94% to 100%) and specificity (98% to 100%). A doctor feeling the belly is far less accurate and is not recommended for screening. (USPSTF, 2019)
What the result means
A radiologist reads the images and sends a report to the doctor who ordered the scan, who shares the results with you. (RadiologyInfo, 2024) The scan measures the width (diameter) of the aorta:
- Normal width: no aneurysm found. The USPSTF recommendation is for one-time screening. (USPSTF, 2019)
- 3.0 centimeters or wider: this is the usual definition of an AAA. (USPSTF, 2019) (NHLBI, 2022) The USPSTF says 90% or more of aneurysms found by screening are small, and the standard of care for stable small ones is to keep checking them with ultrasound at regular intervals, because the risk of rupture is small. (USPSTF, 2019) How often depends on the size; ask your provider what applies to you. (MedlinePlus, 2025) (NHLBI, 2022) You may also have a CT scan or MRI for more detail. (NHLBI, 2022)
An AAA usually grows slowly over many years and rarely causes symptoms, which is why it is screened for. (RadiologyInfo, 2024) RadiologyInfo says a rupture causes intense belly or back pain, dizziness, nausea or shortness of breath. (RadiologyInfo, 2024) What each size band means and how often scans repeat: AAA screening results. Next steps after any screening result: after an abnormal screening result.
Cost and coverage
Medicare covers one AAA screening ultrasound in your lifetime if you are at risk: a family history of AAA, or a man 65 to 75 who has smoked at least 100 cigarettes. You need a referral from your provider, and you pay nothing if your provider accepts assignment. (Medicare.gov) For private plans, see preventive screenings covered by insurance.
Questions people ask
Do I need to fast before an AAA ultrasound?
Often, yes. MedlinePlus says you will likely be asked not to eat or drink for several hours before an abdominal ultrasound, and RadiologyInfo says your doctor will tell you whether to. Follow the instructions you are given. (MedlinePlus, 2024) (RadiologyInfo, 2024)
How long does an AAA screening ultrasound take?
MedlinePlus says an abdominal ultrasound most often takes less than 30 minutes. (MedlinePlus, 2024)
Does an aortic ultrasound use radiation?
No. Ultrasound uses sound waves, not ionizing radiation, and has no known risk. It may feel briefly uncomfortable when the probe is pressed on your belly, but it should not be painful. (MedlinePlus, 2024) (RadiologyInfo, 2024)
What size counts as an abdominal aortic aneurysm?
An AAA is usually defined as an abdominal aorta 3.0 centimeters or larger across. What happens next depends on the size, so your doctor will explain your result. (USPSTF, 2019) (NHLBI, 2022)
Does Medicare pay for AAA screening?
Medicare covers one screening ultrasound in your lifetime if you are at risk: a family history of AAA, or a man 65 to 75 who has smoked at least 100 cigarettes. You need a referral, and you pay nothing if your provider accepts assignment. (Medicare.gov)